METHOD FOR PRODUCING A TAPERED ROLLER ASSEMBLY, TAPERED ROLLER ASSEMBLY AND TAPERED ROLLER BEARING

Abstract

A method is disclosed for producing a tapered roller assembly which can be mounted in a particularly simple manner. For this purpose, a method for producing a tapered roller assembly having an inner ring and a roller ring is proposed, wherein the method comprises the following steps: a) providing the inner ring , wherein the inner ring has a flanged mounting rim which is produced within a preliminary flanging stage by flanging over an edge region of the inner ring; b) mounting the roller ring on the inner ring, wherein the roller ring is pushed over the flanged mounting rim onto the inner ring; c) flanging over the flanged mounting rim into a flanged rim wherein the flanged rim, as a retaining rim, captively retains the roller ring; and d) heat treating the flanged mounting rim before step b) or step c), wherein a hardness of the flanged mounting rim is reduced by comparison with a hardness of a raceway of the inner ring. Also proposed is a tapered roller bearing formed with such a tapered roller assembly.

Claims

1. A method for producing a tapered roller assembly having an inner ring and a roller ring, comprising: providing the inner ring, wherein the inner ring has a flanged mounting rim which is produced in the context of a preliminary flanging stage by flanging an edge region of the inner ring; mounting the roller ring on the inner ring, wherein the roller ring is pushed onto the inner ring via the flanged mounting rim; flanging the flanged mounting rim into a flanged rim, wherein the flanged rim retains the roller ring captive as a retaining rim; heat treating the flanged mounting rim before the mounting step or the flanging step, wherein a hardness of the flanged mounting rim is reduced in comparison with a hardness of a raceway of the inner ring.

2. The method according to claim 1, wherein the flanged mounting rim is formed in the preliminary flanging stage so as to form an angle with the raceway of the inner ring which is in the range of 90 to 180.

3. The method according to claim 1, wherein the flanged rim is formed in such a way that it encloses an angle which is in the range of less than 90 with the raceway of the inner ring.

4. The method according to claim 1, wherein the heat treatment is performed as an RF heat treatment.

5. The method according to claim 1, wherein a cold-flow pressed inner ring is used as the inner ring.

6. The method according to claim 5, wherein the cold-flow pressed inner ring, in a region of the raceway, has no surfaces influenced by material separation processes.

7. The method according to claim 1, wherein the flanging of the flanged mounting rim in the preliminary flanging stage is implemented by a flanging punch moved in the axial direction.

8. The method according to claim 6, wherein cold-flow pressing of the inner ring takes place by a forming device with at least one tool part which conforms to at least the raceway, wherein the forming device has a forming punch, wherein the forming punch is moved in the axial direction.

9. The method according to claim 8, wherein the flanging punch and a forming punch are moved in opposite directions.

10. A tapered roller assembly, wherein the tapered roller assembly is produced by the method according to claim 1.

11. The tapered roller assembly according to claim 10, wherein the inner ring has a maximum thickness of 6 mm in the region of the raceway.

12. The tapered roller assembly according to claim 11, wherein the inner ring has a thickness in the edge region which corresponds to at least 25% of the maximum thickness of the raceway.

13. A tapered roller bearing comprising a tapered roller assembly according to claim 10 further comprising an outer ring.

14. The tapered roller bearing according to claim 13, wherein the outer ring is a cold-flow pressed outer ring.

15. The tapered roller bearing according to claim 13, wherein the inner ring and the outer ring are produced by cold-flow pressing, and, particularly in a region of the raceway of the inner ring and a raceway of the outer ring, have no surfaces influenced by material separation processes.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0037] FIG. 1 shows a flow diagram with several steps of a method for producing a tapered roller assembly;

[0038] FIG. 2 shows a forming device in a half-section for producing an inner ring for the tapered roller assembly in a highly schematic representation; and

[0039] FIG. 3 shows a tapered roller bearing according to the invention in a half-section.

DETAILED DESCRIPTION

[0040] On the right-hand side, FIG. 1 shows a flow diagram with several steps for producing a tapered roller assembly 1. On the left-hand side, the starting products or intermediate products for the production of the tapered roller assembly 1 are shown schematically in half-section.

[0041] The process can proceed, for example, from a circular ring disk 2, which is made of a preferably hardenable steel. The circular ring disk 2 is designed as a flat disk and can, for example, be cut out from a circular blank. In a step 100, which is designed as a forming step, the circular ring disk 2 is formed by cold-flow pressing into an inner ring 3, wherein the inner ring 3 has a fixed rim 4, a conical raceway/runway 5, and an edge region 6 running in an axial direction. The edge region 6 is designed as a hollow-cylindrical end portion of the inner ring 3.

[0042] For example, the inner ring 3 can be produced in the state after step 100 in a forming device 7, as shown schematically in a half-section in FIG. 2. The forming device 7 has two tool parts 8a, b, wherein the tool part 8a forms the runway 5 of the inner ring 3, and the tool part 8b forms an end face of the inner ring 3 on the fixed rim 4. Between the tool parts 8a and 8b, the circular ring disk 2 is inserted and formed into the shape of the inner ring 3 by means of a central forming punch 9 by means of cold-flow pressing. In this case, the edge region 6 is formed by an annular gap between the tool part 8a and the forming punch 9.

[0043] In a step 200, which is designed as a preliminary flanging stage, the edge region 6 is folded or crimped in the direction of the runway 5. In this case, a flanged mounting rim 10 is produced, which has a conical, circumferential surface on the radial inner side and on the radial outer side. The edge region 6 has been formed from the hollow-cylindrical shape into a funnel shape by the forming in the preliminary flanging stage in step 200.

[0044] A possible implementation of step 200 is shown in FIG. 2. As soon as the inner ring 3 is produced with the edge region 6, a flanging punch 11 is set in the axial direction, so that the edge region 6 is formed into the flanged mounting rim 10 in the manner described. The feed direction of the flanging punch 11 is counter to the feed direction of the forming punch 9, represented by the applied forces F acting in opposite directions by means of flanging punch 11 and forming punch 9, respectively,

[0045] In a step 300, which is designed as a heat treatment stage, a local heat treatment of the flanged mounting rim 10 takes place, and, in fact, particularly in the connection region 16 to the runway 5. The local heat treatment can, for example, be carried out by a high frequency heat treatment. As a result of the local heat treatment, the connection region 16 of the flanged mounting rim 10 is made softer than, for example, the runway 5, so that further flanging of the flanged mounting rim 10 is simplified. Furthermore, fractures and cracks are avoided during further flanging.

[0046] In a step 400, which is designed as a mounting stage, a roller rim 12 is assembled, wherein the roller rim 12 comprises a plurality of tapered rollers 13 and a cage 14, in which the tapered rollers 13 are arranged. The cage 14 is designed such that the tapered rollers 13 are held captive between the cage 14 and the runway 5. In particular, the tapered rollers 13 cannot emerge outward from the cage 14 in a radial direction. The geometry of the flanged mounting rim 10 is selected in such a way that the interference contour diameter formed by the flanged mounting rim 10 is smaller than a free diameter of the roller rim 12, so that the roller rim 12 can be pushed or mounted onto the inner ring 3 without deformation of the cage 14. In particular, the selection of a suitable dimensioning avoids damage to the cage 14 in the mounting stage.

[0047] In a step 500, which is designed as a final flanging stage, the flanged mounting rim 10 is further bent or crimped into a flanged rim 15. Thus, the edge region 6 is folded in two steps in the direction of the runway 5. The flanged rim 15 is designed as a retaining rim, which holds the roller rim 12, including the tapered rollers 13 and the cage 14, captive. As a result, the end product, i.e., the tapered roller assembly 1, is designed as a self-supporting assembly which can be easily transported and assembled.

[0048] FIG. 3 shows a tapered roller bearing 20 in half-section with a tapered roller assembly 1 according to FIG. 1, step 500, after the final flanging stage. The roller rim 12 comprising the cage 14 and the tapered rollers 13, as well as the inner ring 3 with the fixed rim 4 and the flanged rim 15, can be seen. Furthermore, an outer ring 17 with a raceway/runway 18 is provided. When the tapered roller bearing 20 is mounted on a shaft, wherein the inner ring 3 is pushed onto the shaft, an assembly tool is pressed axially with a force F against the inner ring 3 in the region of the flanged rim 15. In the region of the flanged rim, no damage occurs, because, due to the two-stage method and the associated reduced material hardening in the final flanging stage, the flanged rim still has sufficient residual ductility to elastically yield to the assembly tool pressed against it.

LIST OF REFERENCE NUMERALS

[0049] 1 Tapered roller assembly [0050] 2 Circular ring disk [0051] 3 Inner ring [0052] 4 Fixed rim [0053] 5 Raceway/Runway [0054] 6 Edge region [0055] 7 Forming device [0056] 8a, b Tool parts [0057] 9 Forming punch [0058] 10 Flanged mounting rim [0059] 11 Flanging punch [0060] 12 Roller ring [0061] 13 Tapered rollers [0062] 14 Cage [0063] 15 Flanging rim [0064] 16 Connecting region [0065] 17 Outer ring [0066] 18 Raceway/Runway [0067] 20 Tapered roller bearing [0068] F Force