CN116995863A - Oil-cooled linear motor and free piston power generation system - Google Patents

Abstract

The present disclosure provides an oil-cooled linear motor and a free piston power generation system. The linear motor includes a casing assembly, a stator assembly, a mover assembly and a cooling assembly. A first oil passage is provided in the stator assembly, and the first oil passage has at least one At the first outlet, the cooling assembly is sleeved on the stator assembly. There are multiple annular oil passages in the cooling assembly. The multiple annular oil passages are arranged along the axial direction. Each annular oil passage is connected in turn. The cooling assembly is provided with an oil inlet. The oil inlet and the oil outlet are connected to the annular oil channel, the oil outlet is connected to the first oil channel, and the first outlet is set above the mover assembly so that the cooling oil can pass through the outlet under pressure drive. The oil port flows through the first oil passage and then reaches the mover assembly by gravity. The cooling oil passage passes through the casing, stator and mover in sequence, which can cool the stator, winding, mover, bearing and other heating components to keep the linear motor temperature space. The distribution is more uniform and the heat dissipation effect is obvious, ensuring the power generation performance of the linear motor.

Description

Oil-cooled linear motor and free piston power generation system

Technical Field

The disclosure relates to the technical field of motors, and in particular relates to an oil-cooled linear motor and a free piston power generation system.

Background

At present, the linear motor has the problems of larger internal loss and quicker temperature rise in some application occasions. For example, the output thrust of a linear motor is closely related to the winding current, and higher current densities in the stator windings can produce a significant amount of copper losses, resulting in higher winding temperatures. If the temperature exceeds the allowable temperature rise limit of the motor material, the problems of insulation failure, structural deformation and the like of the winding of the motor can be caused. For permanent magnet machines, exceeding the permanent magnet temperature tolerance limit will induce irreversible demagnetization. Therefore, a cooling structure with reasonable design is required to cool the linear motor, and the running safety, stability and reliability of the linear motor are ensured.

Disclosure of Invention

To address at least one of the above-mentioned issues, the present disclosure provides an oil-cooled linear motor and a free piston power generation system.

The first aspect of the present disclosure proposes an oil-cooled linear motor, the linear motor comprising: the stator assembly is installed in the shell assembly, the rotor assembly and the stator assembly are at a certain distance in the radial direction, the rotor assembly can be driven to perform relative movement with the stator assembly, a first oil duct is arranged in the stator assembly, and the first oil duct is provided with at least one first outlet; the cooling assembly is sleeved on the stator assembly, a plurality of annular oil ducts are arranged in the cooling assembly, the annular oil ducts are axially distributed, the annular oil ducts are sequentially communicated, the cooling assembly is provided with at least one oil inlet and at least one oil outlet, the oil inlet and the oil outlet are communicated with the annular oil ducts, the at least one oil outlet is communicated with the first oil duct, part or all of the first outlet is arranged above the rotor assembly, so that cooling oil passes through the oil outlet under pressure driving, flows through the first oil duct and then reaches the rotor assembly through gravity.

According to one embodiment of the disclosure, the oil inlet is arranged radially outside the cooling assembly.

According to one embodiment of the present disclosure, at most one of the annular oil passages is in direct communication with one of the oil inlets.

According to one embodiment of the disclosure, at least part of the oil inlet is arranged at the highest position of the cooling assembly.

According to one embodiment of the present disclosure, the cooling assembly is provided with two oil inlets that are respectively in direct communication with annular oil passages located at both ends in the axial direction among the plurality of annular oil passages.

According to one embodiment of the disclosure, the oil outlet is arranged at the highest position of the cooling assembly radially inside.

According to one embodiment of the present disclosure, the cooling assembly is provided with only one of the oil outlets that is in direct communication with an annular oil passage that is axially located at an intermediate position among the plurality of annular oil passages.

According to one embodiment of the disclosure, the first oil passage includes at least one axial oil passage and a plurality of radial oil passages, each of the axial oil passages communicates with a plurality of the radial oil passages, the at least one oil outlet communicates with the at least one axial oil passage, and an outlet of each of the radial oil passages is one of the first outlets.

According to one embodiment of the present disclosure, the stator assembly includes a stator yoke, an outer wall surface of which is provided with an axial groove, and the axial oil passage is formed by the axial groove and an inner wall surface of the cooling assembly.

According to one embodiment of the disclosure, the connection of the oil outlet and the axial oil passage is located at the center of the axial oil passage.

According to one embodiment of the present disclosure, the stator assembly includes a plurality of stator windings axially arranged inside the stator yoke, the at least one radial oil passage being disposed between the stator windings.

According to one embodiment of the present disclosure, the first oil passage includes only one of the axial oil passages.

According to one embodiment of the disclosure, the inner side of the bottom of the casing assembly is provided with an oil receiving groove and at least one oil return port, and the at least one oil return port is communicated with the oil receiving groove and is used for forming a communication channel between the inside and the outside of the linear motor so that cooling oil can be discharged to the outside of the linear motor.

According to one embodiment of the disclosure, the housing assembly includes an oil return pan, the oil return pan is disposed at the bottom of the housing assembly, and the oil receiving groove and the at least one oil return port are both disposed on the oil return pan.

A second aspect of the present disclosure proposes a free piston power generation system comprising: the oil-cooled linear motor according to any one of the embodiments described above; one end of the oil delivery pipeline is connected with the cooling oil outlet of the linear motor, and the other end of the oil delivery pipeline is connected with the oil inlet of the linear motor; the driving part is arranged on the oil conveying pipeline and is used for adjusting the pressure in the oil conveying pipeline so as to drive cooling oil to flow from the cooling oil outlet to the oil inlet; and a heat exchange assembly disposed between the cooling oil discharge port and the driving part.

According to one embodiment of the present disclosure, at least one end of the mover assembly of the linear motor is connected with a link assembly, and the driving part includes: at least one plunger assembly, the plunger assembly cover is located link assembly, every plunger assembly is formed with the plunger inner chamber, the internal pressure in plunger inner chamber changes along with the rectilinear motion of mover assembly, the change of internal pressure forms can drive the cooling oil and flows in the drive power of defeated oil pipe way.

According to one embodiment of the disclosure, each plunger assembly includes a plunger and a plunger cylinder, the plunger is disposed on the connecting rod assembly, the plunger cylinder is disposed on the outer side of the casing assembly of the linear motor, the linear motor moving part formed by the mover assembly and the connecting rod assembly penetrates through the plunger inner cavity, and the plunger can move in the plunger cylinder under the drive of the linear motor moving part.

According to one embodiment of the present disclosure, the oil delivery line includes: the heat exchange assembly is arranged on the public pipeline; one end of the first branch pipeline is connected with the outlet of the public pipeline, and the other end of the first branch pipeline is connected with the inlet of the driving part; and one end of the second branch pipeline is connected with the driving part, and the other end of the second branch pipeline is connected with the oil inlet of the linear motor.

According to one embodiment of the present disclosure, the first branch pipe is provided with a first check valve, an inlet of the first check valve is connected with the cooling oil discharge port, and an outlet of the first check valve is connected with the driving part; the second branch pipeline is provided with a second one-way valve, an inlet of the second one-way valve is connected with the driving part, and an outlet of the second one-way valve is connected with the oil inlet.

According to one embodiment of the disclosure, the oil delivery line further comprises a tank assembly and a filter, the tank assembly and the filter being disposed on the common line.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the disclosure and together with the description serve to explain the principles of the disclosure.

Fig. 1 is a schematic diagram of a structure of an oil-cooled linear motor according to one embodiment of the present disclosure.

Fig. 2 is a schematic fluid space diagram of an internal oil gallery of a cooling assembly according to one embodiment of the present disclosure.

Reference numerals:

1-a shell component, 11-a cooling component, 111-an annular oil duct, 112-an oil inlet, 113-an oil outlet, 114-a communication section, 12-an oil return bottom shell, 13-an oil return port and 14-an oil receiving groove;

2-stator assembly, 21-axial oil duct, 22-radial oil duct, 23-stator winding;

3-a mover assembly;

4-linkage assembly, 41-first linkage, 42-first plunger, 43-second linkage, 44-second plunger;

5-oil tank assembly, 51-filter, 52-heat exchange assembly, 53-first plunger cylinder, 531, 541-first check valve, 532, 542-second check valve, 54-second plunger cylinder.

Detailed Description

The present disclosure is described in further detail below with reference to the drawings and the embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the relevant content and not limiting of the present disclosure. It should be further noted that, for convenience of description, only a portion relevant to the present disclosure is shown in the drawings.

In addition, embodiments of the present disclosure and features of the embodiments may be combined with each other without conflict. The technical aspects of the present disclosure will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

Unless otherwise indicated, the exemplary implementations/embodiments shown are to be understood as providing exemplary features of various details of some ways in which the technical concepts of the present disclosure may be practiced. Thus, unless otherwise indicated, features of the various implementations/embodiments may be additionally combined, separated, interchanged, and/or rearranged without departing from the technical concepts of the present disclosure.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, when the terms "comprises" and/or "comprising," and variations thereof, are used in the present specification, the presence of stated features, integers, steps, operations, elements, components, and/or groups thereof is described, but the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof is not precluded. It is also noted that, as used herein, the terms "substantially," "about," and other similar terms are used as approximation terms and not as degree terms, and as such, are used to explain the inherent deviations of measured, calculated, and/or provided values that would be recognized by one of ordinary skill in the art.

The oil-cooled linear motor and free piston power generation system of the present disclosure are described below with reference to the accompanying drawings.

Fig. 1 is a schematic diagram of a structure of an oil-cooled linear motor according to one embodiment of the present disclosure. Referring to fig. 1, this embodiment provides an oil-cooled linear motor, which includes: a housing assembly 1, a stator assembly 2, a mover assembly 3 and a cooling assembly 11. The stator assembly 2 is mounted within the housing assembly 1. The mover assembly 3 is radially spaced from the stator assembly 2. The mover assembly 3 can be driven in a relative movement with the stator assembly 2. A first oil passage is provided in the stator assembly 2, the first oil passage having at least one first outlet. The cooling assembly 11 is sleeved on the stator assembly 2. A plurality of annular oil passages 111 are provided in the cooling assembly 11. All the annular oil passages 111 are axially arranged. The annular oil passages 111 are sequentially communicated with each other. The cooling module 11 is provided with at least one oil inlet 112 and at least one oil outlet 113, each oil inlet 112 and each oil outlet 113 communicating with the above-mentioned plurality of annular oil passages 111. Part or all of the first outlet is provided above the sub-assembly 3 so that the cooling oil reaches the sub-assembly 3 by gravity after flowing through the first oil passage through the oil outlet 113 under pressure.

According to the oil-cooled linear motor provided by the embodiment of the disclosure, the cooling oil circuit comprising the annular oil channel and the first oil channel is arranged in the linear motor, and the cooling oil circuit sequentially passes through the shell, the stator and the rotor, so that heating parts such as the stator, the winding, the rotor and the bearing can be cooled, the temperature space distribution of the linear motor is more uniform, the heat dissipation effect is obvious, the magnetic performance of the permanent magnet is improved, and the power generation performance of the linear motor is ensured.

The housing assembly 1 is a housing of a linear motor, a cavity is formed inside the housing, and the stator assembly 2 and the mover assembly 3 can be installed in the cavity of the housing assembly 1. The outer wall of the stator assembly 2 may be connected with the inner wall of the housing assembly 1. The stator assembly 2 may be cylindrical. The stator assembly 2 is centered by an axially extending cylindrical cavity. The housing assembly 1 may be provided with bearings on both axial sides, and the mover assembly 3 may be partially or entirely located in the cylindrical cavity itself by direct or indirect connection with the bearings. The two ends of the mover assembly 3 in fig. 1 are located outside the stator assembly 2, and the center portion is located in the cylindrical cavity of the stator assembly 2. An air gap is provided between the stator assembly 2 and the mover assembly 3.

The linear motor in the present embodiment may be operated in a motor mode to convert electric energy into mechanical energy, or may be operated in a generator mode to convert mechanical energy into electric energy. The linear motor can mainly work in a generator mode to generate electricity. When the linear motor is in an operating state, the rotor assembly 3 makes linear reciprocating motion along the axial direction, and the stator assembly 2 keeps the position of the stator assembly in the casing assembly 1.

A first oil passage is formed in the stator assembly 2. The first oil passage has one or more first outlets. The first outlet may be disposed on an inner wall of the stator assembly 2, and a communication portion between the first oil passage and the oil outlet 113 may be disposed on an outer wall of the stator assembly 2, so that an oil passage line of the first oil passage may cover the stator assembly 2 in a radial direction, and a cooling range of the stator assembly 2 may be increased.

Fig. 2 is a schematic fluid space diagram of an internal oil gallery of a cooling assembly according to one embodiment of the present disclosure. Referring to fig. 2, the cooling assembly 11 may be mounted to the housing assembly 11 as part of a linear motor housing. A plurality of annular oil passages 111 are provided in the cooling module 11. The annular oil passage 111 may have a circular annular cross section in the axial direction and a rectangular cross section in the circumferential direction. The inner diameter of each annular oil passage 111 may be the same, and the outer diameter may be the same. The annular oil passages 111 are arranged along the axial direction of the stator assembly 2 so that the overall space formed by all the annular oil passages is in a ring-like column shape. Accordingly, the cooling module 11 may also be a circular cylinder, so that the flow resistance of the cooling oil is substantially equal everywhere within the cooling module 11.

The inner wall surface of the circular column can be connected with the stator assembly 2, and the end surfaces of the two ends can be connected with the shell assembly 11. The annular oil channels 111 are sequentially communicated in the axial direction, the annular oil channels 111 at two ends are adjacent to and communicated with one annular oil channel, and the other annular oil channels 111 are adjacent to and communicated with two annular oil channels at two sides of the annular oil channel respectively.

Communication segments 114 may be provided between the annular oil passages 111, each communication segment 114 connecting two adjacent annular oil passages 111 together such that a parallel relationship is formed between all annular oil passages 111. The cross section of the communication section 114 in the circumferential direction may be the same size and shape as the cross section of the annular oil passage 111 in the circumferential direction. The positions of the respective communication segments 114 in the circumferential direction of the annular oil passage 111 may not be identical so that the annular oil passage 111 connected to two adjacent communication segments at the same time is a common oil passage, and the positions of the two adjacent communication segments in the circumferential direction may be located on opposite sides of the common oil passage in the circumferential direction.

The cooling module 11 has one or more oil inlets 112 and one or more oil outlets 113. As shown by the arrow in the linear motor in fig. 1, after cooling oil enters from the oil inlet 112 under the drive of pressure, the cooling oil reaches the oil outlet 113 through the annular oil duct 111, and heat conducted from the outer wall of the stator assembly 2 to the cooling assembly 11 is absorbed, so that self cooling and indirect cooling of the stator assembly 2 are realized. The cooling oil enters the first oil duct from the oil outlet 113, and then flows out from the first outlet, so that heat generated by the windings and other parts of the stator assembly 2 is directly absorbed, and direct cooling of the stator assembly 2 is realized.

A part of the first outlets of the stator assembly 2 may be disposed directly above the mover assembly 3, or all of the first outlets may be disposed directly above the mover assembly 3. When the cooling oil reaches the oil outlet 113, the cooling oil can freely fall onto the rotor assembly 3 from the first outlet, and the problem that heat is difficult to dissipate due to the fact that an air gap with low heat conductivity coefficient exists between the permanent magnet on the rotor assembly 3 and the stator assembly 2 is solved by utilizing direct contact type oil cooling, so that the cooling requirement of the rotor assembly 3 is met.

The rotor assembly 3 can throw the cooling oil on the rotor assembly to the bearings at two sides of the rotor assembly 3 in the moving process, so that the bearings are cooled. The cooling oil may then flow out of the housing assembly 1 from the oil return passage of the housing assembly 1.

It can be appreciated that the cooling oil is used as the cooling medium, so that the cooling medium can directly enter the linear motor to cool the heat generating component in a direct contact manner, for example, enter the stator assembly 2 and pass through the rotor assembly 3, thereby cooling the stator assembly 2 and the rotor assembly 3, and compared with indirect cooling by water cooling, the cooling effect is better.

For example, referring to FIG. 2, the oil inlet 112 may be disposed radially outward of the cooling module 11. For example, the oil inlet 112 is disposed at a position on the upper half of the cooling assembly 11 and faces away from the center of the annular oil duct 111, so as to facilitate injection of cooling oil. The axial position of the oil inlet 112 may be the same as the axial position of one of the annular oil passages 111, so that the path of the oil inlet 112 to the annular oil passage 111 is shortest.

The same annular oil passage 111 is at most in direct communication with one oil inlet 112. That is, at most one oil inlet 112 is corresponding to the radial outer side of the same annular oil duct 111, so that the oil inlets 112 can be uniformly distributed on the cooling assembly 11, thereby facilitating uniform distribution of cooling effect and expansion of cooling range.

At least a portion of the oil inlet 112 may be disposed at the highest position of the cooling module 11. The highest position here means that the oil inlet 112 is located at the highest position of all positions of the cooling module 11 radially outside in the stationary state or in the operating state of the linear motor, for example, at the top of the outer ring of the cooling module 11, with the oil inlet 112 facing directly above. In each oil inlet 112, only one oil inlet 112 may be located at the highest position of the cooling module 11, only a part of the oil inlets 112 may be located at the highest position of the cooling module 11, or all the oil inlets 112 may be located at the highest position of the cooling module 11, where all the oil inlets 112 are linearly arranged.

The cooling module 11 may be provided with two oil inlets 112 in total, and the two oil inlets 112 are respectively in direct communication with the annular oil passages 111 at both ends in the axial direction among all the annular oil passages 111. The cooling assembly 11 is provided with a corresponding oil inlet 112 at the outermost annular oil passage 111 at each end, and the total of two oil inlets 112, cooling oil can enter the cooling assembly 11 from the end sides through the two oil inlets 112 to form two paths of oil paths, and the two paths of oil paths flow to the oil outlets 113 from two different directions, so that the cooling range can completely cover the stator assembly 2 in the axial direction.

The oil outlet 113 may be provided at the radially inner highest position of the cooling module 11. The highest position here means that the oil outlet 113 is located at the highest position of all positions of the cooling assembly 11 radially inside in the stationary state or in the operating state of the linear motor, for example, at the top of the inner ring of the cooling assembly 11, with the oil outlet 113 facing directly below. The oil inlet 112 and the oil outlet 113 correspond to different annular oil passages 111, respectively, so as to increase the length of the oil passage and further enlarge the coverage of the cooling range.

The cooling assembly 11 may be provided with only one oil outlet 113, the oil outlet 113 being in direct communication with the annular oil passage 111 located at an axially intermediate position among the annular oil passages 111. This enables the lengths of the oil passages from the different oil inlets 112 to the oil outlets 113 to be the same, so that the flow resistance of the cooling oil is substantially equal everywhere within the cooling assembly 11, and equalization of the heat radiation effect is achieved. At this time, the oil inlet 112 at one end passes through the three annular oil passages 111 to reach the annular oil passage 111 located in the center corresponding to the oil outlet 113, thereby reaching the oil outlet 113, the oil inlet 112 at the other end passes through the other three annular oil passages 111 to reach the annular oil passage 111 located in the center corresponding to the oil outlet 113, thereby reaching the oil outlet 113, the cooling oil flow directions of the two oil passages are opposite in the axial direction, and the cooling ranges of the two oil passages are added together, thereby being able to cover the entire stator assembly 2.

For example, referring to fig. 1, the first oil passage may include at least one axial oil passage 21 and a plurality of radial oil passages 22, each axial oil passage 21 may communicate with the plurality of radial oil passages 22, the at least one oil outlet 113 may communicate with the at least one axial oil passage 21, and an outlet of each radial oil passage 22 is a first outlet.

The axial oil passages 21 are axially extending oil passages, each axial oil passage 21 being circumferentially arranged along the stator assembly 2. The number of the oil outlets 113 may be the same as the number of the axial oil passages 21, and each oil outlet 113 corresponds to each axial oil passage 21 one by one. It will be appreciated that the number of oil outlets 113 may also be greater than the number of axial oil passages 21 such that at least some of the axial oil passages 21 have a plurality of oil outlets 113 for supplying oil, or the number of oil outlets 113 may also be less than the number of axial oil passages 21 such that at least some of the axial oil passages 21 share and split cooling oil provided by one of the oil outlets 113.

The radial oil passages 22 may be oil passages extending in the radial direction, and each radial oil passage 22 may be linearly arranged in the axial direction or may be arranged in an array. The axes of the radial oil passages 22 that connect with the same axial oil passage 21 may be parallel to each other. Assuming that the first oil passage includes n axial oil passages 21, each of the n axial oil passages 21 is connected to the oil outlet 113, and each of the axial oil passages 21 is connected to m radial oil passages, the first oil passage includes n×m first outlets in total. The length of the axial oil passage 21 may be set depending on the number of connected radial oil passages 22, and the length of the axial oil passage 21 is generally greater than or equal to the distance between the radial oil passages 22 at both axial ends of all the radial oil passages 22 connected thereto.

The stator assembly 2 may include a stator yoke, an outer wall surface of which is provided with an axial groove, through which an axial oil passage 21 is formed with an inner wall surface of the cooling assembly 11. The stator assembly 2 may include a stator core that is assembled on an inner sidewall surface of the cooling assembly 11, including a stator tooth portion and a stator yoke portion. The outer wall surface groove of the stator yoke forms the bottom and side walls of the axial oil passage 21, and the inner wall of the cooling assembly 11 forms the top wall of the axial oil passage 21. The wall surface groove is used as the axial oil duct 21, so that the axial oil duct 21 is conveniently opened, and the oil outlet 113 and the axial oil duct 21 are not required to be butted by arranging redundant parts, so that the tightness between the stator assembly 2 and the cooling assembly 11/the shell assembly 1 is only required to be ensured.

The junction of the oil outlet 113 and the axial oil passage 21 may be located at the center of the axial oil passage. Since the heat dissipation requirement of the axial intermediate position is greater than that of the axial both end positions, the alignment of the oil outlet 113 to the intermediate position of the axial oil passage 21 can enhance the cooling effect to the intermediate position of the stator assembly 2. At this time, the oil outlet 113 is located at the axial center position of both the cooling module 11 and the stator module 2.

The stator assembly may include a plurality of stator windings 23, each stator winding 23 being axially arranged inside the stator yoke, each radial oil passage 22 being disposed between the stator windings 23.

The stator core may further include a plurality of stator teeth and a plurality of stator windings 23, the stator teeth and the stator windings 23 being arranged in a staggered manner in the axial direction, the stator teeth being spaced apart on an inner circumference of the stator yoke, and the stator windings 23 being also spaced apart on the inner circumference of the stator yoke. One end of the radial oil passage 22 is connected to the axial oil passage 21, and the other end penetrates the inner side wall of the stator core. A radial oil passage 22 may be provided between each two stator windings 23, the radial oil passage 22 being provided in the stator teeth. The stator teeth may be arranged axially, and a stator slot may be formed between every two stator teeth, and the stator winding 23 is disposed at the stator slot. By providing the radial oil passage 22 in the stator core, the heat generation amount of the core and the winding can be taken away, and the core and the winding can be efficiently cooled.

The first oil passage may include only one axial oil passage 21. At this time, the cooling assembly 11 is correspondingly provided with two oil inlets 112 and one oil outlet 113, the annular oil duct 111, the axial oil duct 21 and the radial oil duct 22 are sequentially communicated, and after cooling oil enters from the oil inlets 112, the cooling oil can rapidly flow to the axial oil duct 21 through the annular oil duct 111 and the oil outlet 113 and then flow to different radial oil ducts 22.

The bottom inside of the casing assembly 1 may be provided with an oil receiving groove 14 and at least one oil return port 13, the oil return port 13 communicating with the oil receiving groove 14 for forming a communication passage between the inside and the outside of the linear motor so that the cooling oil can be discharged to the outside of the linear motor.

The casing assembly 1 may include an oil return bottom shell 12, the oil return bottom shell 12 is disposed at the bottom of the casing assembly 1, and the oil return port 13 and the oil receiving groove 14 may be disposed on the oil return bottom shell 12. The oil return pan 12 may be separate from other structural parts of the housing assembly 1, and the housing assembly 1 is formed by mounting the oil return pan 12 to the other structural parts. As shown by the arrows in the linear motor in fig. 1, after the cooling oil flows out of the radial oil passage 22 and drops onto the mover assembly 3, part of the oil directly flows down from the mover assembly 3, and the other part of the oil is thrown off onto the bearing and flows down along the wall surface of the casing assembly 1, and these oil eventually flow into the oil receiving groove 14.

The oil receiving groove 14 may be an axial groove, and the length in the axial direction may be set to be greater than or equal to the distance between two wall surfaces provided with bearings, so that oil can normally flow into the oil receiving groove 14 without staying at other positions, and the length in the radial direction of the oil receiving groove 14 may be set to cover both the radial position of the mover assembly 3 and the radial position of the bearings, so that the oil flowing out of the radial oil passage 22 is ensured to flow back into the oil receiving groove 14.

The return opening 13 is a through hole and may be directed to a horizontal side or to a lower side. The oil return port 13 is used for providing a communication channel between the oil receiving groove 14 and the outside to the oil receiving groove 14, so that oil can flow out of the linear motor from the oil receiving groove 14 through the oil return port 13. The oil return port 13 may be provided in one or more. The oil return port 13 is disposed at one side of the oil receiving groove 14, and may be disposed at one side of the housing assembly 1. The oil receiving groove 14 may be provided as a curved surface or a plane having a certain inclination angle, and the oil return port 13 may be located at a lower position or a lowest position of the surface of the oil receiving groove 14, so that formation of a dead zone on the oil receiving groove 14 such that oil is retained in the dead zone and cannot flow out is avoided.

For example, the inner side wall surface of the oil return bottom shell 12 is the bottom surface of the casing assembly 1, the oil receiving groove 14 is located at the middle part of the oil return bottom shell 12 and penetrates through the oil return bottom shell 12 in the axial direction, and the bottom surface of the oil receiving groove 14 is a plane inclined towards the direction of a certain vertex of the inner space of the casing assembly 1. The oil return port 13 may be provided at the lowest position of the oil receiving groove 14, that is, at a position of the oil receiving groove 14 nearest to the apex. The oil flowing to the oil receiving groove 14 will be influenced by gravity and all flow to the direction of the vertex, so the oil will all flow to the oil return opening 13, so that the oil return opening 13 can collect all the oil in the oil receiving groove 14, and then the oil is discharged out of the linear motor. For another example, the oil return bottom shell 12 is in an inverted cone shape, the oil receiving groove 14 is in a reverse cone shape, and the oil receiving opening 13 is positioned at the cone tip of the reverse cone.

With continued reference to fig. 1, this embodiment proposes a free-piston power generation system, which may be a free-piston internal combustion power generation system. The free piston power generation system includes: the device comprises a linear motor, an oil pipeline, a driving part and a heat exchange assembly. The linear motor is the oil-cooled linear motor according to any one of the embodiments described above. The linear motor includes: a housing assembly 1, a stator assembly 2, a mover assembly 3 and a cooling assembly 11. The stator assembly 2 is mounted within the housing assembly 1. The mover assembly 3 is radially spaced from the stator assembly 2. The mover assembly 3 can be driven in a relative movement with the stator assembly 2. A first oil passage is provided in the stator assembly 2, the first oil passage having at least one first outlet. The cooling assembly 11 is sleeved on the stator assembly 2. A plurality of annular oil passages 111 are provided in the cooling assembly 11. All the annular oil passages 111 are axially arranged. The annular oil passages 111 are sequentially communicated with each other. The cooling module 11 is provided with at least one oil inlet 112 and at least one oil outlet 113, each oil inlet 112 and each oil outlet 113 communicating with the above-mentioned plurality of annular oil passages 111. Part or all of the first outlet is provided above the sub-assembly 3 so that the cooling oil reaches the sub-assembly 3 by gravity after flowing through the first oil passage through the oil outlet 113 under pressure.

One end of the oil delivery pipeline is connected with a cooling oil outlet of the linear motor, and the other end of the oil delivery pipeline is connected with an oil inlet of the linear motor. When the linear motor discharges the cooling oil, which has performed endothermic cooling of the stator assembly 2 and the mover assembly 3, through the oil return port 13, the cooling oil discharge port corresponds to the oil return port 13.

The driving part is arranged on the oil conveying pipeline and used for adjusting the pressure in the oil conveying pipeline so as to drive the cooling oil to flow from the cooling oil outlet to the oil inlet.

The heat exchange assembly 52 is disposed between the cooling oil discharge port and the driving portion.

According to the free piston power generation system provided by the embodiment of the disclosure, the heat-absorbed cooling oil discharged by the linear motor is radiated through the heat exchange component through the oil conveying pipeline, and the cooled cooling oil is conveyed to the oil inlet again for circulating flow cooling, so that the oil cost is reduced and the radiating effect is ensured.

After cooling oil enters the linear motor from the oil inlet 112, the cooling oil passes through the annular oil duct 111, the axial oil duct 21 and the radial oil duct 22, is finally collected by the oil receiving groove 14 and is collected at the oil return port 13, the cooling oil is sucked into the oil conveying pipeline under negative pressure, and firstly, the cooling oil is subjected to heat dissipation through the heat exchange component 52, and the heat exchange component 52 can be a heat exchanger with heat dissipation fins on the surface. Then the cooling oil flows through the driving part and then is pushed to flow to the oil inlet 112 by positive pressure, so that the cooling oil is conveyed outside the linear motor, and one complete cycle of the cooling oil is completed. The driving forces of the negative pressure suction and the positive pressure pushing are all from the driving part, the driving part provides negative pressure suction force for the oil pipeline between the driving part and the oil return port 13, and the driving part provides positive pressure pushing force for the oil pipeline between the driving part and the oil inlet 112.

When the cooling module 11 of the linear motor is provided with a plurality of oil inlets 112 and the linear motor is provided with only one oil return port 13, the oil delivery pipe may be provided with a common pipe and a plurality of branch pipes. Taking the cooling module 11 as an example, two oil inlets 112 are provided, and two branch pipes are correspondingly provided. One end of the common pipeline is connected with the oil return port 13, and the heat exchange assembly 52 is arranged on the common pipeline, so that each path of cooling oil dissipates heat through the same heat exchange assembly 52. The other end of the public pipeline is connected with one end of the two branch pipelines. The other ends of the two branch pipes are respectively connected with two oil inlets 112. The driving parts may be provided in two correspondingly, each of which is provided on one of the branch pipes. It will be appreciated that the oil delivery lines may be provided without a common line, in which case each oil delivery line is provided with a respective heat exchange assembly 52.

It should be noted that, details not disclosed in the free piston power generation system of the present embodiment may refer to details disclosed in the oil-cooled linear motor of the above embodiment provided in the present invention, and will not be described herein.

Illustratively, at least one end of the mover assembly 3 of the linear motor may be connected with a link assembly 4. The driving part may include at least one plunger assembly, the plunger assemblies are sleeved on the connecting rod assembly 4, each plunger assembly is formed with a plunger inner cavity, the linear motion of the inner pressure follow-up sub-assembly of the plunger inner cavity changes, and the change of the inner pressure forms a driving force capable of driving the cooling oil to flow in the oil conveying pipeline.

According to the free piston power generation system provided by the embodiment of the disclosure, the power driving cooling oil circuit of the reciprocating motion output by the free piston engine of the free piston power generation system can be directly used for circulating, cooling oil is conveyed to the annular oil duct cooling structure on the linear motor shell component through the plunger inner cavity, an additional power device is not needed, and the connecting rod between the rotor component and the piston can be cooled through the cooling oil flowing through the plunger component, so that heat transfer from the high-temperature piston to the linear motor rotor is effectively blocked.

The linkage assembly 4 may include one or more links. Continuing with the example of the cooling module 11 being provided with 2 oil inlets 112, the connecting rod assembly 4 may include two connecting rods, a first connecting rod 41 and a second connecting rod 43, respectively. The first link 41 may be connected to one end of the mover assembly 3, and the second link 43 may be connected to the other end of the mover assembly 3. The first link 41, the second link 43 and the mover assembly 3 form a linear motor moving part, and the first link 41 and the second link 43 move together with the mover assembly 3. The free piston power generating system may include a free piston engine, and the connecting rod assembly 4 may be connected to a moving part of the free piston engine and perform a linear reciprocating motion according to the movement of the moving part.

The number of the plunger assemblies may correspond to the number of the oil inlets 112, and the number of the plunger assemblies is two at this time, wherein one plunger assembly is sleeved on the first connecting rod 41, and the other plunger assembly is sleeved on the second connecting rod 43. Each plunger assembly defines a plunger cavity, which may be a closed cavity. After the cooling oil completes at least one cooling cycle, the plunger inner cavity is filled with the cooling oil. When the mover assembly moves in the first direction, the first plunger cavity increases in pressure with movement of the mover assembly, and the second plunger cavity decreases in pressure with movement of the mover assembly. When the mover assembly moves in a second direction opposite to the first direction, the first plunger cavity experiences a pressure decrease as the mover assembly moves, and the second plunger cavity experiences a pressure increase as the mover assembly moves. For cooling oil in the oil delivery line, the cooling oil may be caused to flow toward the oil inlet 112 whether the pressure of the plunger bore in the oil delivery line is increasing or decreasing.

The high-temperature piston and the linear motor rotor conduct heat through the connecting rod, the heat load of the high-temperature piston directly acts on the linear motor rotor to affect the performance of the linear motor, and cooling oil flows through the plunger assembly, so that the connecting rod section positioned in the inner cavity of the plunger can be cooled by the cooling oil, and heat conduction from the connecting rod to the rotor assembly is blocked.

Each plunger assembly can comprise a plunger and a plunger cylinder body, the plunger is arranged on the connecting rod assembly 4, the plunger cylinder body is arranged on the outer side of the casing assembly 1 of the linear motor, a linear motor moving part formed by the rotor assembly 3 and the connecting rod assembly 4 penetrates through the plunger inner cavity, and the plunger can move in the plunger cylinder body under the driving of the linear motor moving part.

When the free piston power generation system is configured with two plunger assemblies, the two plunger assemblies are a first plunger assembly and a second plunger assembly, respectively. The two plunger assemblies respectively correspond to two oil conveying pipelines, wherein one of the plunger assemblies is a first oil conveying pipeline, and the other plunger assembly is a second oil conveying pipeline. Each oil line is assumed to be provided with a dedicated heat exchange assembly 52. The first plunger assembly is arranged on the first oil pipeline, and the second plunger assembly is arranged on the second oil pipeline.

The first plunger assembly comprises a first plunger 42 and a first plunger cylinder 53, the first plunger 42 is fixedly sleeved on the first connecting rod 41, the first plunger cylinder 53 is fixedly installed on one side of the shell assembly 1 facing the first connecting rod 41, and the first plunger 42 and the first plunger cylinder 53 form a closed first plunger inner cavity. The first link 41 extends through the first plunger bore.

The second plunger assembly comprises a second plunger 44 and a second plunger cylinder 54, the second plunger 44 is fixedly sleeved on the second connecting rod 43, the second plunger cylinder 54 is fixedly mounted on one side of the casing assembly 1 facing the second connecting rod 43, and the second plunger 44 and the second plunger cylinder 54 form a closed second plunger inner cavity. The second link 43 extends through the second plunger bore.

When the mover assembly 3 moves in the left direction in fig. 1, the first plunger 42 moves leftwards, the volume of the inner cavity of the first plunger increases to cause the pressure to decrease, the second plunger 44 moves leftwards, the volume of the inner cavity of the second plunger decreases to cause the pressure to increase, and at this time, in the first oil delivery pipeline, the cooling oil in the pipeline from the heat exchange assembly 52 to the first plunger cylinder 53 flows to the first plunger cylinder 53 by the driving force of negative pressure suction; in the second oil delivery line, the cooling oil in the line from the second plunger cylinder 54 to the oil inlet 112 flows toward the oil inlet 112 by the driving force of the positive pressure pushing.

When the rotor assembly 3 moves to the right direction in fig. 1, in the first oil conveying pipeline, the cooling oil in the pipeline from the first plunger cylinder 53 to the oil inlet 112 flows to the oil inlet 112 under the driving force of positive pressure pushing; in the second oil delivery line, the cooling oil in the line from the heat exchange unit 52 to the second plunger cylinder 54 flows toward the second plunger cylinder 54 by the driving force of suction of negative pressure. Thus, both oil delivery pipelines realize the flow of cooling oil towards the oil inlet 112, so that the cooling oil is conveyed to the annular oil passage cooling structure on the linear motor shell through the plunger cylinder body on the rotor connecting rod in each stroke.

Each oil delivery line may include: a common line, at least one first branch line and at least one second branch line. The heat exchange assembly 52 is disposed on a common line. One end of the first branch pipeline is connected with an outlet of the public pipeline, and the other end of the first branch pipeline is connected with an inlet of the driving part. One end of the second branch pipeline is connected with the driving part, and the other end of the second branch pipeline is connected with an oil inlet 112 of the linear motor. In this case, the individual heat exchange elements 52 are not provided for each oil line, but share the same heat exchange element 52.

The cooling oil passes through the heat exchange assembly 52 of the common pipeline after exiting from the oil return port 13, then enters the corresponding first branch pipeline from the common pipeline under pressure driving, then enters the second branch pipeline, and finally enters the corresponding oil inlet 112.

The first branch pipe may be provided with a first check valve, an inlet of which is connected with the cooling oil discharge port, and an outlet of which is connected with the driving part. The second branch pipeline can be provided with a second one-way valve, the inlet of the second one-way valve is connected with the driving part, and the outlet of the second one-way valve is connected with the oil inlet.

Of the two oil delivery pipelines in fig. 1, a first branch pipeline of the left oil delivery pipeline is provided with a first check valve 531, a second branch pipeline of the left oil delivery pipeline is provided with a second check valve 532, a first branch pipeline of the right oil delivery pipeline is provided with a first check valve 541, and a second branch pipeline of the right oil delivery pipeline is provided with a second check valve 542.

Reverse flow of oil is avoided by the check valve so that when the mover assembly 3 moves in the left direction in fig. 1, the second check valve 532 prevents the cooling oil in the second branch line on the left side from flowing back into the first plunger cylinder 53, and the first check valve 541 prevents the cooling oil in the second plunger cylinder 54 on the right side and the cooling oil in the first branch line from flowing back into the common line; and such that when the mover assembly 3 moves in the right direction in fig. 1, the first check valve 531 causes the cooling oil in the first plunger cylinder 53 on the left side and the cooling oil in the first branch line not to flow back into the common line, and the second check valve 542 causes the cooling oil in the second branch line on the right side not to flow back into the second plunger cylinder 54.

The oil delivery line may further comprise a tank assembly 5 and a filter 51, the tank assembly 5 and the filter 51 being arranged on a common line.

The oil tank assembly 5, the filter 51 and the heat exchange assembly 52 may be connected in sequence, the oil tank assembly 5 is located at the most upstream of the common pipeline, the cooling oil first enters the oil tank assembly 5 after exiting from the oil return port 13, then enters the filter 51 for filtering, then enters the heat exchange assembly 52 for heat dissipation, and then starts to enter the first branch pipeline on the left side or the first branch pipeline on the right side.

The cooling principle of the free piston power generation system of the present embodiment is as follows:

in the steady operation process of the free piston linear power generation system, cylinders at the left side and the right side are sequentially combusted and ignited, and the rotor assembly 3 and the connecting rod assembly 4 reciprocate to drive the first plunger 42 and the second plunger 44 fixedly connected with the rotor assembly to move so as to increase the inner cavity volume of the first plunger cylinder body 53/the second plunger cylinder body 54. Due to the action of the atmospheric pressure, the cooling oil flows from the oil tank assembly 5 through the filter 51 and the heat exchange assembly 52 alternately into the inner cavities of the first plunger cylinder 53 and the second plunger cylinder 54, and the oil absorption process is completed. And the cooling oil is not returned from the cooling unit 11 into the first plunger cylinder 53/second plunger cylinder 54 due to the second check valve 532/second check valve 542. When the mover assembly 3 and the connecting rod assembly 4 drive the first plunger 42 and the second plunger 44 to move so that the inner cavity volume of the first plunger cylinder 53/the second plunger cylinder 54 is reduced, the oil path flowing from the first plunger cylinder 53/the second plunger cylinder 54 to the oil tank assembly 5 is blocked due to the action of the first check valve 531/the third check valve 541, and the cooling oil enters the cooling structure of the linear motor cooling assembly 11 through the pipeline under the pressure.

The cooling oil enters from the upper oil inlet 112 of the cooling component 11 of the linear motor shell 1, and passes through the annular oil duct 111, the oil outlet 113 at the middle inner side of the cooling component 11, the axial oil duct 21 and the radial oil duct 22 in sequence to cool the linear motor stator component 2 sufficiently, and drops on the surface of the rotor component 3 through the radial oil duct 22 on the stator core teeth to cool the linear motor rotor. Part of the cooling oil is thrown to the sliding bearing due to the reciprocating motion of the rotor 3, so that the bearing can be cooled, and the cooling oil can also lubricate the internal components. The cooling oil drops in the oil return bottom shell 12 below under the action of gravity, flows back to the oil tank 5 through the oil return port 13, and finally completes the cooling circulation process.

In the description of the present specification, a description referring to the terms "one embodiment/mode," "some embodiments/modes," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment/mode or example is included in at least one embodiment/mode or example of the present disclosure. In this specification, the schematic representations of the above terms are not necessarily the same embodiments/modes or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments/modes or examples. Furthermore, the various embodiments/implementations or examples described in this specification and the features of the various embodiments/implementations or examples may be combined and combined by persons skilled in the art without contradiction.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present disclosure, the meaning of "a plurality" is at least two, such as two, three, etc., unless explicitly specified otherwise.

It will be appreciated by those skilled in the art that the above-described embodiments are merely for clarity of illustration of the disclosure, and are not intended to limit the scope of the disclosure. Other variations or modifications will be apparent to persons skilled in the art from the foregoing disclosure, and such variations or modifications are intended to be within the scope of the present disclosure.

Claims (10)

1. An oil-cooled linear motor, the linear motor comprising: the stator assembly is installed in the shell assembly, the rotor assembly and the stator assembly are at a certain distance in the radial direction, the rotor assembly can be driven to perform relative movement with the stator assembly, a first oil duct is arranged in the stator assembly, and the first oil duct is provided with at least one first outlet;

The cooling assembly is sleeved on the stator assembly, a plurality of annular oil ducts are arranged in the cooling assembly, the annular oil ducts are axially distributed, the annular oil ducts are sequentially communicated, the cooling assembly is provided with at least one oil inlet and at least one oil outlet, the oil inlet and the oil outlet are communicated with the annular oil ducts, the at least one oil outlet is communicated with the first oil duct, part or all of the first outlet is arranged above the rotor assembly, so that cooling oil passes through the oil outlet under pressure driving, flows through the first oil duct and then reaches the rotor assembly through gravity.

2. The linear motor of claim 1, wherein the oil outlet is disposed at a highest position of the cooling assembly radially inward.

3. The linear electric machine of claim 1, wherein the first oil passage includes at least one axial oil passage and a plurality of radial oil passages, each of the axial oil passages being in communication with a plurality of the radial oil passages, the at least one oil outlet being in communication with the at least one axial oil passage, the outlet of each of the radial oil passages being one of the first outlets.

4. A linear motor according to claim 3, wherein the stator assembly includes a stator yoke, an outer wall surface of the stator yoke being provided with an axial groove, the axial oil passage being formed by the axial groove and an inner wall surface of the cooling assembly.

5. The linear motor of claim 1, wherein the bottom inside of the housing assembly is provided with an oil receiving groove and at least one oil return port communicating with the oil receiving groove for forming a communication passage between the inside and the outside of the linear motor so that cooling oil can be discharged to the outside of the linear motor.

6. A free piston power generation system comprising:

an oil-cooled linear motor as claimed in any one of claims 1 to 5;

one end of the oil delivery pipeline is connected with the cooling oil outlet of the linear motor, and the other end of the oil delivery pipeline is connected with the oil inlet of the linear motor;

the driving part is arranged on the oil conveying pipeline and is used for adjusting the pressure in the oil conveying pipeline so as to drive cooling oil to flow from the cooling oil outlet to the oil inlet; and

and the heat exchange assembly is arranged between the cooling oil outlet and the driving part.

7. The free piston power generating system of claim 6, wherein at least one end of the mover assembly of the linear motor is connected with a connecting rod assembly, and the driving part comprises:

at least one plunger assembly, the plunger assembly cover is located link assembly, every plunger assembly is formed with the plunger inner chamber, the internal pressure in plunger inner chamber changes along with the rectilinear motion of mover assembly, the change of internal pressure forms can drive the cooling oil and flows in the drive power of defeated oil pipe way.

8. The free piston power generation system of claim 7, wherein each plunger assembly comprises a plunger and a plunger cylinder, the plunger is arranged on the connecting rod assembly, the plunger cylinder is arranged on the outer side of a shell assembly of the linear motor, a linear motor moving part formed by the rotor assembly and the connecting rod assembly penetrates through the plunger inner cavity, and the plunger can move in the plunger cylinder under the driving of the linear motor moving part.

9. The free-piston power generation system of claim 6, wherein the oil delivery line comprises:

the heat exchange assembly is arranged on the public pipeline;

One end of the first branch pipeline is connected with the outlet of the public pipeline, and the other end of the first branch pipeline is connected with the inlet of the driving part; and

and one end of the second branch pipeline is connected with the driving part, and the other end of the second branch pipeline is connected with the oil inlet of the linear motor.

10. The free piston power generating system according to claim 9, wherein a first check valve is provided on the first branch pipe, an inlet of the first check valve is connected to the cooling oil discharge port, and an outlet of the first check valve is connected to the driving portion; the second branch pipeline is provided with a second one-way valve, an inlet of the second one-way valve is connected with the driving part, and an outlet of the second one-way valve is connected with the oil inlet.