CN1095528C - Structure-changeable self-adaptive sliding bearing - Google Patents

Abstract

The present invention relates to a structure-changeable self-adaptive sliding bearing which is composed of a tiltable bush, a fixed bush and a shaft, wherein the tiltable bush and the fixed bush keep sliding contact in the mutual matching position, and can cooperate to work to generate a variable-step line. According to the step number and the existing condition of preload steps, the present invention provides a step and tiltable bush structure-changeable bearing, a dual-step and tiltable bush structure-changeable bearing, a preload step and tiltable bush structure-changeable bearing. The servo structure-changeable bearing has the characteristics of strong self-adaptive ability, large bearing capacity and high stability, and can be used for the bearing design for turbine generator sets, etc. with high requirement conditions.

Description

Variable Structure Adaptive Sliding Bearing

The invention belongs to the technical field of sliding bearings, and in particular relates to a sliding bearing with a step structure that can be changed according to motion by utilizing the sliding contact between the tilting pad and the fixed pad with the ability of reversing and cooperating with each other. So-called variable structure adaptive plain bearings.

At present, typical sliding bearings used in rotating machinery generally include fixed pad bearings and tilting pad bearings [US Patent 5795077: Tilting Pad Journal Bearing, patent authorization date: August 18, 1998] [US Patent 5482380: Double Tilting Pad Journal Bearing, Patent Grant Date: January 9, 1996]. The fixed pad bearings generally include round bearings, elliptical bearings, stepped bearings, etc. Step bearings have the characteristics of large load-carrying capacity, but relatively speaking, their dynamic characteristics are poor and they are prone to self-excited oscillations; bearer. However, in the case of load fluctuations during operation, a fixed step height cannot achieve optimal load-carrying capacity. Bearing stability is an important requirement for modern high-speed rotating supports. Although the tilting pad bearing has good stability and is widely used in high-speed rotating machines, it has the characteristic of relatively low load-carrying capacity.

The object of the present invention is to provide a variable structure self-adaptive sliding bearing, which has the characteristics of high stability at high speed and light load and high load carrying capacity at low speed and heavy load.

The object of the present invention is achieved in this way, it comprises tilting pad, upper pad, fixed pad and axle, and its characteristic is: the oil inlet end of tilting pad and the oil outlet end of fixed pad are in contact with each other, and the tilting pad The fulcrum position is close to the oil inlet side, and the tilting pad and the fixed pad form a stepped line at the joint.

Another feature of the present invention is that the position parameter θ ₁ /θ ₂ of the fulcrum of the tilting pad is 0.3-0.6.

The present invention obtains a variable structure self-adaptive sliding bearing because the tilting pad and the fixed pad are used to maintain sliding contact at the joint and produce a variable structure that can follow the load or when the rotating speed changes. In the variable structure self-adaptive sliding bearing, the step is formed by the cooperation of the tilting pad and the fixed pad or similar devices, and the formed step is a variable step that can be automatically adjusted according to the actual condition of the bearing. . In order to produce such a fit, the ability to reverse during the motion of the tilting pad is required.

Fig. 1 is a schematic structural diagram of an embodiment proposed by the present invention.

The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments.

Referring to Fig. 1, the embodiment of the variable structure adaptive sliding bearing proposed according to the present invention is a so-called step-tilt pad variable structure bearing. It consists of upper tile 4, fixed tile 6, tiltable tile 10, pad positioning device 11 and shaft 5. The upper tile 4 is provided with a circumferential oil groove 1, and the oil groove 1 divides the upper tile 4 into two front and rear tile surfaces 2 and 3. The tile surface 7 of the fixed tile 6 is a fixed tile surface, and the tile body or the tile foundation 15 of the fixed tile 6 supports a tiltable tile 10 simultaneously. When the tile surface 16 of the tilting tile 10 and the tile surface 7 of the fixed tile 6 are on the same circumference, the contact line between the back side 14 of the tilting tile 10 and the supporting surface 15 of the fixed tile 6 is 12, which is the fulcrum of the tilting tile 10 at this moment. Location. The 13 points (representing a contact line) on the back of the tile of the tilting tile 10 are contact points or fulcrums when the tiles of the tilting tile 10 have the maximum swing angle. The tilting pad 10 and the fixed pad 6 have a sliding contact fit, wherein the contact line 8 on the tilting pad is an arc segment with the center at 12, and the contact line 9 on the fixed pad 6 is an arc with the center at 13 section, which can ensure that the tilting pad 10 can swing or roll freely within a certain range. The position of the fulcrum of the tilting pad is generally designed to be close to the oil outlet side, that is, θ ₁ /θ ₂ ≥ 0.5. Such a fulcrum position design has the ability to make the pad of the tilting pad swing in the same direction as the rotating shaft, which is called positive direction swing. However, in the bearing structure proposed by the present invention, the fulcrum 12 of the tilting pad 10 is close to the oil inlet side of the pad. Calculation and analysis show that the swinging of the tilting pad 10 can have the rotation ability that the swing angle is opposite to the rotation direction of the rotating shaft. called reverse swing. Generally, if the design of the tilting pad bearing is θ ₁ /θ ₂ <0.5, the reverse motion of the tilting pad will cause the bearing to lose its carrying capacity. The design principle and structure proposed by the present invention are completely different from the general tilting pad design. The inverted design produced by this structure is just conducive to the formation of a stepped line at the joint between the tilting pad 10 and the fixed pad 6, that is, a stepped bearing will be produced as a result of the mating action of the pads. This kind of step formed by using the reverse effect will greatly improve the bearing capacity of the whole bearing, especially when the bearing load fluctuates or bears dynamic load, the step height mentioned above will be automatically adjusted with the load, thus producing a variable step structure bearings. The bearing constructed by the invention has the characteristics of variable structure with load, self-adaptation and follow-up capability. This kind of bearing shows the positive swing characteristics of the tilting pad 10 when the load is small or the speed is high, that is, there is no step effect, or the reverse swing is accompanied by a small step height. It has the working characteristics of a tilting pad bearing, so the bearing has high stability. When this kind of bearing bears a large load or the rotation speed is very low, it shows the characteristics of the tilting pad 10 swinging in the opposite direction and the follow-up change in the height of the large step, so that the whole bearing has more of a step bearing with a large bearing capacity. features. This kind of bearing not only has high stability at high speed and light load, but also has large carrying capacity at low speed and heavy load. This is exactly the goal pursued by modern support technology. Furthermore, the bearing can be preloaded by raising the position of the fulcrum 12 of the tilting pad 10 . Calculation and analysis show that the preload coefficient can be taken as 0.1~0.5. The preload factor is V=δ/C, where δ is the lift and C is the bearing radius clearance. The variable structure bearing provided by the present invention has the advantages of larger load capacity and higher stability at the same time.

The position of the fulcrum 12 of the tiltable pad in the present invention will be further described below. The design of the tilting pad fulcrum position in the present invention is different from that of the existing tilting pad fulcrum position. Calculation and analysis show that when the above-mentioned bearing preload coefficient V is taken as 0.1 to 0.5, the fulcrum position parameter θ ₁ /θ ₂ corresponds to It can be taken as 0.3-0.6, where θ ₁ is the angle between the fulcrum position 12 and the oil inlet edge of the tilting pad 10 , and θ ₂ is the wrap angle of the tilting pad 10 . The variable structure self-adaptive sliding bearing involved in the invention can be used in the design of bearings with higher requirements such as in steam turbine generator sets.

Compared with other existing sliding bearings, the present invention takes into account the advantages of good stability of the tilting pad and large bearing capacity of the stepped bearing. Therefore, this kind of bearing has the characteristics of simple structure, large carrying capacity, high stability and strong adaptability.

Claims (2)

1. A variable structure adaptive sliding bearing, which includes a tilting pad, an upper pad, a fixed pad and a shaft, characterized in that: the oil inlet end of the tilting pad is in contact with the oil outlet end of the fixed pad, and can be The fulcrum of the tilting pad is close to the oil inlet side, and the tilting pad and the fixed pad form a stepped line at the joint. 2. The variable structure adaptive sliding bearing according to claim 1, characterized in that: the fulcrum position parameter θ ₁ /θ ₂ of the tilting pad is 0.3-0.6.

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