WO2008067794A2 - Hollow roller of a cylindrical roller bearing, method for producing a corresponding hollow roller - Google Patents

Abstract

The invention relates to a hollow roller (1) for a cylindrical roller bearing with an outer ring and an inner ring, between which rolling elements that are configured as rollers are arranged. At least one roller is configured as a hollow roller (1) which consists of at least two tubes (2, 3, 9) that are coaxially pressed into each other, an inner peripheral surface (5) of a radially outer tube (2) resting with its entire surface on an outer peripheral surface (4) of a radially inner tube (3), and a radially inner tube (3; 9) comprising a bore (7) that is open at both ends. The aim of the invention is to improve durability of said hollow roller (1) and to adjust its prestress in a simple manner. For this purpose, the radially inner tube (3; 9) is overdimensioned in relation to the radially inner diameter of the radially outer tube (2) and the following ratios apply for the diameters of the individual tubes (2, 3, 9) in relation to the outer diameter D<SUB>W</SUB>, the joining diameter D<SUB>F</SUB> and the inner diameter D<SUB>Wi</SUB> of the finished hollow roller (1): the diameter ratio Q<SUB>i</SUB> = D<SUB>Wi</SUB> / D<SUB>W</SUB> of the hollow roller (1) is greater or equal 0.5 and smaller or equal 0.8; the diameter ratio Q<SUB>ii</SUB> = D<SUB>Wi</SUB> / D<SUB>F</SUB> of the inner tube (3; 9) is greater or equal 0.5 and smaller or equal 0.9; the diameter ratio Q<SUB>ai</SUB> = D<SUB>F</SUB> / D<SUB>W</SUB> of the outer tube (2) is greater or equal 0.6 and smaller or equal 0.95.

Description

 Hollow roller of a cylindrical roller bearing, method for producing such a hollow roller

description

Field of the invention

The invention relates to a hollow roller for a cylindrical roller bearing with outer ring and inner ring, between which rolling elements designed as rolling elements are arranged, of which at least one roller is designed as a hollow roller, which consists of at least two coaxially pressed into each other tubes, wherein an inner circumferential surface of a radially outer tube full contact with an outer circumferential surface of a radially inner tube, and in which a radially inner tube has a bore.

Furthermore, the invention relates to a method for producing such a hollow roller. Background of the invention

In cylindrical roller bearings and in other rolling bearings, the load is transmitted in principle by rolling elements, in the case of cylindrical roller bearings by cylindrical rollers. For linear or rotary motion of the cylindrical roller bearing and the rolling elements must be moved. This movement takes place, for example, in the case of linear guides at half the speed of the two cylindrical roller bearing parts, which usually consist of carriages and rail in the case of linear bearings.

The energy required for this movement is generally transmitted by frictional forces. For this purpose, appropriate normal forces between the rolling elements and the raceway are required. If the normal forces are too low, slip occurs between the treads. Such slip conditions cause the rollers no longer rotate with their kinematic speed around their own axis and the rolling element no longer moves kinematically.

To avoid Wälzkörper- or Wälzkörpersatzschlupf, it is known to use a negative operating clearance, so a bias. This is often the case with tapered bearings, but is rarely used in needle, cylindrical roller and spherical roller bearings, as this leads to other disadvantages, such as increased friction. In order to prevent rolling element slip, individual larger rolling elements have already been installed in the rolling element set.

For example, DE 197 34 980 A1 proposes a change-speed gearbox with at least one gear wheel mounted on a gear shaft via a cylindrical roller bearing which can be coupled to the gear shaft via a coupling element, radially between an inner raceway assigned to the gear shaft and a hub of the gearwheel assigned outer race cylindrical hollow rollers are arranged in a cylindrical roller bearing cage. At least one hollow roller is elastically deformable radially biased, wherein its diameter is greater than the diameter of the remaining cylindrical rolling elements.

The one-piece hollow roller can consist of a plastic, of a thin-walled hollow steel body or of a spirally or helically wound spring steel. Hollow rollers have the disadvantage that in the region of the bore a bending-tension alternating voltage occurs, which is unfavorable in the rolling elements commonly used. On the other hand, hollow rollers also have principal advantages. They are characterized by a low weight, are flexible and easy to compress, which is emphasized in particular in US Pat. No. 3,930,693, which likewise relates to one-piece hollow rollers.

There have also been described multi-part hollow rollers and rollers with concentric individual components. For example, DE 566 062 C discloses a roll for roller bearings which consists of a core and one or more mechanically firmly joined cladding layers in order to limit the propagation of a crack, in particular starting from the centering holes of the roll. The purpose of such an embodiment is that crack formation during clamping of the blank for the purpose of material processing is avoided.

US Pat. No. 642,204 also discloses a hollow roller of a cylindrical roller bearing in which a tubular insert of compressed fibers is inserted into a hollow roller, which surrounds the bore and serves to increase the durability of a pin or bolt guided through the bore. which is in direct contact with the coating to increase. From DE 101 49 833 B4 a hollow roller is known, which is made according to the local Fig. 4 of two coaxially arranged and radially spaced pipe sections, said ends of an outer tube section are deformed by rotational deformation such that they on the radially inner pipe section to the plant come. As a result, a cylindrical annular cavity is created in the roller, wherein through the radially inner pipe section in the rolling body a hole open on both sides is formed which is separated from the cylinder-shaped cavity by the component wall of the radially inner pipe section. With such a configured hollow role a rolling element with low weight but the same stability of a solid body to be realized, so that a hollow shaft designed in this way is not suitable for setting a bias voltage.

Finally, DE 39 19 199 A1 describes a method for producing a hollow roller with the features of the preamble of claim 1. A described in relation to the local figure 2 hollow shaft consists of three coaxially pressed into each other tubes, in which an inner circumferential surface of a radially outer tube the entire surface rests against an outer circumferential surface of a radially inner tube, wherein a radially inner tube forms a bore open on both sides, which serves to guide a cage bolt. The hollow roller described there is except for the bore, which has a small diameter, held quite solid. The adjustment of a bias by the design of the hollow role plays no role in this document.

A disadvantage of previously known hollow rollers, which are used in cylindrical roller bearings to produce or adjust a bias, is the difficulty with which the bias can be adjusted. Furthermore, the durability of such known hollow rollers leaves something to be desired in operation, since internal stresses or bending-tension alternating voltages often lead to premature failure of these hollow rollers. Object of the invention

The invention has for its object to provide a hollow roller, which does not have the disadvantage of high bending tension alternating voltages, and allows a bias in Wälzkörpersatz in a simple constructive manner. Furthermore, a further object is to improve the (long) durability, in particular the durability, of such a hollow roller and to allow easy adjustment of a desired bias.

Summary of the invention

The invention is based on the finding that the stated object can be achieved in that the hollow roller consists of nested tubes, wherein at least one inner tube has an excess before joining, so that by the connection of a tension on the outer tube is produced. In addition, it has been shown that the stated object can be achieved by the fact that the inner tube and the outer tube have certain diameter ratios.

The invention is therefore based on a hollow roller for a cylindrical roller bearing with outer ring and inner ring between which rolling elements designed as rollers are arranged, of which at least one roller is designed as a hollow roller, which consists of at least two coaxially pressed into each other tubes, wherein an inner Outer surface of a radially outer tube over its entire surface on an outer circumferential surface of a radially inner tube, and in which a radially inner tube has a bore.

In addition, it is provided in this hollow roller, that the radially inner tube has an excess, in particular from 0.1% to 15%, compared to the radially inner diameter of the radially outer tube, and that for the diameter of the individual tubes with respect to the outer diameter Dw . the joint diameter D _F and on the inner diameter D _W i of the finished hollow roll the following conditions apply:

The diameter ratio Qi = D _w i / D _{w of} the hollow roller is greater than or equal to 0.5 and less than or equal to 0.8.

The diameter ratio Qu = D _W i / DF of the inner tube is greater than or equal to 0.5 and less than or equal to 0.9.

The outer tube diameter ratio Q _a i = D _F / Dw is greater than or equal to 0.6 and less than or equal to 0.95.

With these features, advantageously, a hollow roll is created in which bending tension alternating stresses in the region of the inside diameter of the hollow roll are significantly reduced during circulation of the hollow roll in the cylindrical roller bearing. As a result, it is now possible to execute not only individual but all rolling elements of the cylindrical roller bearing as hollow rollers. In addition, it has been found in studies compared to conventional hollow rollers that results in a 30% to 50% longer life of the hollow roller.

In addition, it may be provided that the diameter ratio Qi of the hollow roll is 0.725, that the diameter ratio Qn of the inner pipe is 0.806, and that the diameter ratio Q _a i of the outer pipe is 0.900. These values have been found in experiments to be particularly favorable.

Furthermore, in this hollow roller can also be provided that the radially inner tube has an excess in a range of 0.1% to 15% relative to the radially inner diameter of the radially outer tube. In another practical development can be provided that the hollow roller consists of two to five nested tubes. A further embodiment of the invention provides that the nested tubes of a hollow roller have the same axial lengths. Likewise, it is within the scope of the invention to provide that one tube has a shorter axial length than another tube.

In a particularly practical embodiment of the invention, it is provided that the radially outer tube has a radially inner circumferential surface, which has a conical shape, and that the radially inner tube has a radially outer surface, which also has a conical geometry, wherein the two conical Lateral surfaces are employed against each other.

Also particularly advantageous is an embodiment of the invention, which is characterized in that the tubes consist of the same or different materials. It is preferred that at least one tube consists of a bearing steel, for example, a 10OCrβ steel.

Finally, an embodiment of the invention is particularly advantageous, which is characterized in that the inner tube is made of aluminum, sintered material, a low alloy steel or an alloy with memory effect.

Furthermore, it is particularly advantageous if at least two of the tubes are connected to one another via an adhesive or solder joint.

It may also be particularly preferred in a development that at least one of the joining surfaces is provided with a coating which is particularly suitable for preventing fretting corrosion and / or changing the coefficient of friction in the joining surfaces. Finally, a refinement of the invention is advantageous, in which at least between two of the tubes a micro positive connection, in particular by knurling, is produced.

In the method according to the invention for producing a hollow roller as described, it is provided that the inner tube is widened in a partially plastic manner only after the joining, so that a permanent surface pressure is created in a joint between the inner tube and the outer tube.

Brief description of the drawings

The invention will be explained in more detail below with reference to the accompanying drawings. It shows

1 shows a cross section through a first embodiment of a hollow roller according to the invention,

2 shows a longitudinal section through the hollow roller of FIG. 1,

3 shows a cross section through a second embodiment of a hollow roller according to the invention,

4 shows a longitudinal section through the hollow roller of FIG. 3, and

5 shows a longitudinal section through a third embodiment of a hollow roller according to the invention, Detailed description of the drawing

In Figures 1 and 2, a first embodiment of a hollow roller 1 according to the invention in cross-section and in longitudinal section is shown. The hollow roller 1 serves as a rolling element of a cylindrical roller bearing, not shown, with outer ring and inner ring, between which rolling elements designed as rollers are arranged, of which at least one roller is designed as a hollow roller 1. The hollow roller 1 may have a larger or equal diameter compared to the other, solid rollers.

The hollow roller 1 according to Figures 1 and 2 consists of two coaxially pressed into each other tubes 2 and 3, wherein the radially inner tube 3 is coaxially pressed into the radially outer tube 2. The radially outer circumferential surface 4 of the radially inner tube 3 rests against the radially inner circumferential surface 5 of the radially outer tube 2 over its entire surface. The radially inner circumferential surface 6 of the radially inner tube 3 forms a bore 7, while the radially outer circumferential surface 8 of the radially outer tube 3 forms the outer surface of the hollow roller 1 and thus the outer diameter.

The diameter of the radially inner circumferential surface 6 of the radially inner tube 3 is indicated by D _W j, the diameter at the joint between the radially outer surface 4 of the radially inner tube 3 and the radially inner circumferential surface 5 of the radially outer tube 2 with DF, and the diameter of the hollow roller 1 and the radially outer surface 8 of the radially outer tube with D _w . The radius of the radially outer circumferential surface 8 of the radially outer tube 2 is denoted by r _a , the radius to the joint with r _F and the radius of the inner diameter of the hollow roller with r-.

In the illustrated embodiment, the diameters D _w = 50.8 mm, Dwi = 36.8 mm and D _F = 45.7 mm. This results in the following diameter ratios Q: The diameter ratio Q ₁ of the hollow roll 1 is D _W j / D _w = 0.725.

The diameter ratio Q _{11 of} the inner tube 3 is D _W j / D _F = 0.806.

The diameter ratio Q _a ι of the outer tube 2 is D _F / D _w = 0.900.

The axial length of the hollow roller 1 is 104 mm in the illustrated embodiment.

In comparative investigations with a conventional, one-piece hollow roller with identical length and identical outside diameter, an inner diameter Dwi of 40.6 mm and a diameter ratio Qi of 0.80 has surprisingly been found that the comparison stresses of the inventively designed hollow roller 1 is 30% higher than that conventional one-piece hollow roll was. Compared to the one-piece hollow roller, the bias could be adjusted significantly better and more precisely, in particular by the excess of the inner tube. 3

The outer diameter of the inner tube 3 is in fact greater by 0.1 to 15% before being pressed into the outer tube 3 than after being pressed in. The inner tube is thus pressed with a defined excess in the outer tube 2. As a result, a bias voltage is selectively generated in the outer tube 2, whereby at the same time disadvantageous alternating bending stresses during operation in the hollow roller 1 are reduced. Furthermore, this makes it possible to avoid or at least reduce the bending-tension alternating stress on the inner diameter of the hollow roll 1 during circulation of the hollow roll 1. As the material for the outer tube 2 and for the inner tube 3, grade 100Cr6 steel was used. However, it is also within the scope of the invention to use a different material for the inner tube 3, for example a low-alloy steel, aluminum or an alloy with a memory effect.

In addition, it is possible to produce the inner tube 3 made of a material with a relation to the material of the outer tube 2 lower or higher temperature expansion coefficient. It can thereby be achieved that the introduced in the finished hollow roll bias is set lower or higher at low temperatures.

FIGS. 3 and 4 show a second exemplary embodiment of a hollow roller 1 according to the invention in cross-section or in longitudinal section. The hollow roller 1 according to these figures also consists of two coaxially pressed into each other tubes 2 and 3, wherein the radially inner tube 3 is coaxially pressed into the radially outer tube 2. The radially outer circumferential surface 4 of the radially inner tube 3 abuts the entire surface of the radially inner circumferential surface 5 of the radially outer tube 2. The radially outer surface 8 of the radially outer tube 3 forms the outer surface of the hollow roller 1 and thus the outer diameter.

In contrast to the variant shown in Figures 1 and 2, the hollow roller 1 according to Figures 3 and 4, a third tube 9, which forms the bore 7 with its radially inner surface 10, while the radially outer surface 11 of this tube. 9 on the radially inner circumferential surface 6 of the inner tube 3 rests. The two inner tubes 3 and 9 have been pressed in a process step each with a defined excess in the outer tube 2. The axial length of the inner or middle tube 3 deviates from the axial lengths of the radially inner tube 9 and the outer tube 2. While the outer tube 2 and the radially inner tube 9 have the same lengths, the tube 3 is shorter than the other two tubes. Ren tubes 2 and 9. However, it is within the scope of the invention to form the radially inner tube 9 with a radially outer tube 2 and / or with a deviating from the radial tube 3 length.

Characterized in that the three tubes 2, 3 and 9 have different axial lengths, the suspension behavior of the hollow roller 1 is positively influenced over its axial length transversely to the raceway of the rolling bearing. Such a hollow role

1, which is made of the cylindrical nested tubes 2, 3 and 9, can behave like a profiled roll. The differently long inner tubes 2 and 9 are also used for targeted adjustment of the bias in the assembled hollow roller. 1

FIG. 5 shows a longitudinal section of a third exemplary embodiment of a hollow roller 1 according to the invention, in which the shape of the tubes 2 and 3 inserted into one another is not cylindrical, but is conical on one side. Therefore, the radially outer tube 2 has a thick-walled end edge 12 and an opposite thin-walled end edge 13, so that the radially inner circumferential surface 5 of the radially outer tube 2 extends in an angle deviating from 90 °, in the illustrated embodiment at an angle of 86 °.

Accordingly, the radially inner tube 3 also has a thin-walled end edge 14 and opposite a thick-walled end edge 15 so that the radially outer surface 4 of the radially inner tube 3 extends at a different angle from 90 °, wherein the conical lateral surfaces 4 and 5 of the tubes 2 and 3 are employed against each other.

When joining the two tubes creates a press fit of the two

Tubes 2 and 3, which leads to a particularly durable composite. Furthermore, it has been shown that it is due to the conical design of the two tubes

2, 3 is particularly easy to adjust the roller outer diameter. In addition, the joining of the hollow roller 1 can be carried out only after the bearing assembly, so that only then creates the bias in the camp. The bearing can then be mounted like a bearing without preload.

In contrast to the embodiment shown in FIG. 5, it is also possible to form the conical inner tube 3 shorter than the conical outer tube 2, which leads to a particularly simple assembly of a hollow roller 1 configured in this way.

LIST OF REFERENCE NUMBERS

I Hollow roller 2 Outer tube

3 inner tube

4 Outer lateral surface of the inner tube. 3

5 Inner circumferential surface of the outer tube. 2

6 Inner surface of the inner tube 3 7 hole

8 Outer lateral surface of the outer tube 2

9 inside pipe

10 Inner surface of the tube 9

I 1 Outer lateral surface of the tube 9 12 end edge

13 front edge

14 front edge

15 front edge

Claims

claims 1. hollow roller (1) for a cylindrical roller bearing with outer ring and inner ring, between which rolling elements designed as rolling elements are arranged, of which at least one roller as a hollow roller (1) is formed, which consists of at least two coaxially pressed into each other tubes (2, 3, 9 ), wherein an inner circumferential surface (5) of a radially outer tube (2) over the entire surface of an outer circumferential surface (4) of a radially inner tube (3) is present, and wherein a radially inner tube (3, 9) has a bore (7 ), characterized in that the radially inner tube (3; 9) has an oversize relative to the radially inner diameter of the radially outer tube (2), and that for the diameter of the individual tubes (2, 3, 9) with respect to the outer diameter D _w , the joint diameter D _F and on the inner diameter D _W j of the finished hollow roller (1) the following conditions apply: the diameter ratio Qj = D _w i / Dw of the hollow roll (1) is greater than or equal to 0.5 and less than or equal to 0.8; the diameter ratio Q _U = D _W / D _{F of} the inner tube (3; 9) is greater than or equal to 0.5 and less than or equal to 0.9; the diameter ratio Q _a i = D _F / Dw of the outer tube (2) is greater than or equal to 0.6 and less than or equal to 0.95. 2. hollow roller according to claim 1, characterized in that the diameter ratio Q _{1 of} the hollow roller (1) has a value of 0.725, that the diameter ratio Q _{n of} the inner tube (3; 9) is 0.806, and that the diameter ratio Q _{a of} the outer tube (2) has a value of 0.9. 3. hollow roller according to claim 1 or 2, characterized in that the hollow roller (1) consists of two to five nested tubes (2, 3, 9). 4. hollow roller according to at least one of claims 1 to 3, characterized in that the tubes (2, 3, 9) have the same axial lengths. 5. hollow roller according to at least one of claims 1 to 3, characterized in that a tube (2, 3, 9) has a shorter axial length than another tube (2, 3, 9). 6. hollow roller according to at least one of claims 1 to 5, character- ized in that the radially outer tube (2) has a radially inner Having lateral surface (5) with a conical geometry, and that the radially inner tube (3) has a radially outer surface (4) with a conical geometry, wherein the two conical lateral surfaces (4, 5) are employed against each other. 7. Hollow roller according to at least one of claims 1 to 6, characterized in that the tubes (2; 3; 9) consist of the same or different materials. 8. Hollow roller according to claim 7, characterized in that at least one tube (2; 3; 9) consists of a rolling bearing steel, in particular of a 100Cr6 steel. 9. hollow roller at least according to claim 7, characterized in that the inner tube (3; 9) consists of aluminum, sintered material, a low alloy steel or an alloy with memory effect. 10. hollow roller according to at least one of the preceding claims, characterized in that at least two of the tubes are connected to one another via an adhesive or solder joint. 11. hollow roller at least one of the preceding claims, characterized in that at least one of the joining surfaces is provided with a coating which is particularly suitable for preventing fretting corrosion and / or change in the coefficient of friction in the joining surfaces. 12. hollow roller according to at least one of the preceding claims, characterized in that at least between two of the tubes, a micro-positive connection, in particular by knurling, is made. 13. A method for producing a hollow roller according to one of claims 1 to 12, wherein the inner tube is widened partially plastic after joining, so that in a joint between the inner tube and the outer tube a permanent surface pressure arises.