WHEELSET BEARING FOR A RAIL VEHICLE, AND RAIL VEHICLE

Abstract

A wheelset bearing for a rail vehicle includes a rolling bearing assembly (7) with three bearing rings (4, 8, 9), specifically two inner rings (4, 8) provided for connection to a wheelset shaft (2) and one outer ring (9) provided for connection to a housing (6). The rolling bearing assembly (7) is designed as a quadruple-row angular contact ball bearing in an O arrangement, and two rolling element rows (16, 17) are provided contacting a first inner ring (4) in order to absorb axial forces in a first direction and two rolling element rows (18, 19) are provided contacting a second inner ring (8) in order to absorb forces in the opposite axial direction. A rail vehicle with such an arrangement is also provided.

Claims

1. A wheelset bearing for a rail vehicle, the wheelset bearing comprising: a rolling bearing assembly including first and second inner rings provided for connection to a wheelset shaft and one outer ring provided for connection to a housing; the rolling bearing assembly is configured as a quadruple-row angular contact ball bearing in an O arrangement, including two rolling element rows that contact the first inner ring in order to absorb axial forces in a first direction, and two rolling element rows that contact the second inner ring in order to absorb forces in an opposite axial direction; and either the first and second inner rings or the outer ring for receiving each said rolling element row is/are formed with a single-shoulder rolling element raceway, the single-shoulder rolling element raceway, viewed in cross-section along a central axis through the wheelset bearing, is bounded by a radial line extending perpendicular to the central axis through a rolling element center of each rolling element of the rolling element row, and the rolling element raceway extends from the radial line and from the rolling element center in a direction of a shoulder over an angle in a range from 35 to 75° to a reference point with a constant radius, and the rolling element raceway is formed from the reference point following a tangent applied to the rolling element raceway at the reference point.

2. The wheelset bearing according to claim 1, wherein a the diameter of the rolling elements of two outer ones of the rolling element rows is at least 5% and at most 25% larger than a diameter of the rolling elements of two inner ones of the rolling element rows.

3. The wheelset bearing according to claim 2, wherein a contact angle of the two outer rolling element rows deviates from the contact angle of the two inner rolling element rows by no more than 6°.

4. The wheelset bearing according to claim 3, wherein the contact angle of each said rolling element row is at least 24° and at most 36°.

5. The wheelset bearing according to claim 4, wherein all of the rolling element rows of the rolling bearing assembly have a uniform contact angle of 30°.

6. The wheelset bearing according to claim 1, wherein the outer ring has the single-shoulder rolling element raceway for each said rolling element row.

7. The wheelset bearing according to claim 1, wherein an axial play of two outer ones of the rolling element rows is less than an axial play of two inner ones of the rolling element rows.

8. The wheelset bearing according to claim 7, wherein there is no axial play on two outer ones of the rolling element rows.

9. The wheelset bearing according to claim 7, wherein an axial play on two inner ones of the rolling element rows is more than 10 μm.

10. A rail vehicle comprising at least one wheelset shaft on which at least one said wheelset bearing according to claim 1 is arranged.

11. A wheelset bearing, comprising: a rolling bearing assembly including first and second inner rings provided for connection to a shaft and one outer ring provided for connection to a support; first inner and first outer rolling element rows of rolling elements that contact the first inner ring to absorb axial forces in a first direction and second inner and second outer rolling element rows of rolling elements that contact the second inner ring to absorb forces in an opposite axial direction, the rolling bearing assembly is configured as a quadruple-row angular contact ball bearing in an O arrangement; and either the first and second inner rings or the outer ring for receiving each said rolling element row is/are formed with single-shoulder rolling element raceways, the single-shoulder rolling element raceways, viewed in cross-section along a central axis through the wheelset bearing, are each bounded by a radial line extending perpendicular to the central axis through a rolling element center of each rolling element of the respective rolling element rows, and the rolling element raceway extends from the radial line and from the rolling element center in a direction of a respective shoulder over an angle in a range from 35 to 75° to a reference point with a constant radius, and the respective rolling element raceway is formed from the reference point following a tangent applied to the rolling element raceway at the reference point.

12. The wheelset bearing according to claim 11, wherein a diameter of the rolling elements of the two outer rolling element is at least 5% and at most 25% larger than a diameter of the rolling elements of the two inner rolling element rows.

13. The wheelset bearing according to claim 12, wherein a contact angle of the two outer rolling element rows deviates from the contact angle of the two inner rolling element rows by no more than 6°.

14. The wheelset bearing according to claim 13, wherein the contact angle of each said rolling element row is at least 24° and at most 36°.

15. The wheelset bearing according to claim 14, wherein all of the rolling element rows of the rolling bearing assembly have a uniform contact angle of 30°.

16. The wheelset bearing according to claim 11, wherein the outer ring has the single-shoulder rolling element raceways for each said rolling element row.

17. The wheelset bearing according to claim 11, wherein an axial play of the two outer rolling element rows is less than an axial play of the two inner rolling element rows.

18. The wheelset bearing according to claim 17, wherein there is no axial play on the two outer rolling element rows.

19. The wheelset bearing according to claim 17, wherein an axial play on the two inner rolling element rows is more than 10 μm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In the following, an exemplary embodiment of the disclosure is explained in more detail by means of a drawing. In the figures:

[0027] FIG. 1 shows a wheelset bearing in a sectional view,

[0028] FIG. 2 shows a detail of the wheelset bearing.

DETAILED DESCRIPTION

[0029] A wheelset bearing, generally designated 1, is used to support a wheelset shaft 2 in a supporting construction 3 of a rail vehicle (not shown separately). The wheelset bearing 1 comprises a rolling bearing assembly 7 with two inner rings 4, 8 and a single outer ring 9. An end cap 11, which is screwed to the front end of the wheelset shaft 2 with screws 12, supports the entire rolling bearing assembly 7 in an axial direction. The screws 12 are inserted through bores 14 in the end cap 11. Seals for sealing the rolling bearing assembly 7 on both sides are designated with 13. The rolling bearing assembly 7 is lubricated with a grease as a lubricant.

[0030] The rolling bearing assembly 7 is constructed as a quadruple-row angular contact ball bearing in the form of a twin tandem bearing. The individual rolling element rows are denoted by 16, 17, 18, 19. The rolling element rows 16, 17 roll on the inner ring 4 on the left in the arrangement according to FIG. 1, and the rows of rolling elements 18, 19 on the bearing channel ring 8 on the right. The rolling element raceways of the inner rings 4, 8 are denoted by 21, the total of four rolling element raceways of the outer ring 9 are denoted by 22. The rolling elements 10, 23 of each rolling element row 16, 17, 18, 19 are guided in a cage 20.

[0031] The rolling element rows 16, 17 support the wheelset shaft 2 in relation to the bearing housing 6 in a first axial direction. The rolling element rows 18, 19 are used for support in the opposite axial direction. The entire rolling bearing assembly 7 is mirror-symmetrical to a plane placed between the bearing races 4, 8. As can be seen in particular from FIG. 2, the diameter of the rolling elements 10 of the two inner rolling element rows 17, 18, denoted by D1, is smaller than the diameter of the rolling elements 23 of the two outer rolling element rows 16, 19, denoted by D2. By definition, a circle drawn through all the rolling element centers WM of a rolling element row 16, 17, 18, 19 represents the pitch circle of the relevant rolling element row 16, 17, 18, 19. The pitch circle diameter of the inner rolling element rows 17, 18 is smaller than the pitch circle diameter of the outer rolling element rows 16, 19.

[0032] The total of four raceways 21 provided by the bearing inner rings 4, 8 are each designed in the form of grooves. In contrast to this, the rolling element raceways 22 of the outer ring 9 are each designed as single-shoulder raceways with the shape of half a groove. In FIG. 2, different tangents T1, T2 are applied to the rolling element raceways 22, which are each placed through a reference point BP1, BP2. In any case, the reference point BP2 lies on a radial line RL, which is laid through the rolling element center point WM and lies in a plane to which the central axis 5 of the rolling bearing assembly 7 represents a surface normal. The tangent T2, on which the reference point BP2 lies, is aligned parallel to the axis of rotation of the rolling bearing assembly 7, i.e., to the central axis 5 of the wheelset shaft 2. The single-shouldered shape of the rolling element raceway 22 is expressed by the fact that all tangents which can be applied to the raceway 22 are inclined in one and the same sense with respect to the central axis 5 or, in the extreme case, which is the case with the tangent T2, are spaced parallel from the central axis 5. The tangent T1 on which the reference point BP1 lies is close to the shoulder. Starting from the radial line RL and the rolling element center point WM, the reference point BP1 lies here on a line which encloses an angle β1, β2 of approximately 48° with the radial line RL.

[0033] Starting from the reference point BP1, the rolling element raceway 22 follows a tangent T1 applied to the rolling element raceway 22 at the reference point BP1. The rolling element raceway 22, which guides the rolling elements 10, 23, does not have a constant radius in the outer area in the direction of the shoulder, but instead has a tangential run out following the tangent T1. This ensures that edge stresses are avoided with higher axial loads, such as can occur in railway applications; for example, due to rail joints, since the contact ellipse does not “run up” on a sharp-edged transition, but can spread out elliptically in the tangential run out. The tangent T2 is provided on the other side of the rolling element track 22, which dictates the course of the rolling element track 22 and is also intended to enable the contact ellipse to spread unhindered. Edge stresses can thus be avoided. This improves the friction behavior and extends the service life of the wheelset bearing.

[0034] The rolling bearing rows 17, 18 are also located in the area of the inner rings 4, 8 in single-shoulder rolling bearing raceways 21. A tangent T3 is created at the reference point BP3, which defines the course of the rolling element raceway 21 and which is also intended to enable the contact ellipse to spread unhindered. Only the rolling bearing rows 16, 19 are in the area of the inner rings 4, 8 in two-shouldered rolling bearing raceways 24.

[0035] According to the usual definition, pressure lines denoted by DL run through the rolling element centers WM and the contact points on the bearing rings 4, 8, 9. The contact angles denoted by α1, α2, which are given on the outer rolling element rows 16, 19 and on the inner rolling element rows 17, 18, are uniformly 30° in the exemplary embodiment. The assembly direction designated MR indicates the direction in which the outer ring 9 is to be displaced relative to the inner ring 8 when the rolling bearing assembly 7 is assembled. After assembly, the rolling elements 23 of the outer rolling element rows 16, 19 are arranged without play in the axial direction between the inner ring 4, 8 and the outer ring 9. On the other hand, the inner rolling element rows 17, 18 have a play of more than 10 μm, which is also related to the axial direction.

LIST OF REFERENCE SIGNS

[0036] 1 Wheelset bearing

[0037] 2 Wheelset shaft

[0038] 3 Supporting construction

[0039] 4 Bearing inner ring

[0040] 5 Central axis

[0041] 6 Bearing housing

[0042] 7 Rolling bearing assembly, quadruple-row angular contact ball bearing

[0043] 8 Bearing inner ring

[0044] 9 Bearing outer ring

[0045] 10 Rolling element

[0046] 11 End cap

[0047] 12 Screw

[0048] 13 Seal

[0049] 14 Hole in the end cap

[0050] 15

[0051] 16 Rolling element row

[0052] 17 Rolling element row

[0053] 18 Rolling element row

[0054] 19 Rolling element row

[0055] 20 Cage

[0056] 21 Inner ring raceway

[0057] 22 Outer ring raceway

[0058] 23 Rolling element

[0059] 24 Inner ring track

[0060] α1, α2 Contact angle

[0061] β, β2 Angle

[0062] BP1, BP2, BP3 Reference point

[0063] D1, D2 Rolling element diameter

[0064] DL Pressure line

[0065] MR Assembly direction

[0066] RL Radial line

[0067] T1, T2, T3 Tangent

[0068] WM Rolling element center