Double-row thrust bearing

Abstract

Double-row axial bearing, comprising a bearing disc (2) which is U-shaped in cross section and arranged on one bearing side, and at least two rolling element rings (7, 8) which run on this and are arranged radially one inside the other, the rolling element rings (7, 8) each comprising a plurality of needle- or roller-shaped rolling elements (9, 10), wherein at least one of the rolling element rings (7, 8) runs on a separate further bearing disc (19, 20) arranged on the other bearing side, characterized in that each rolling element ring (7, 8) runs on a separate further bearing disc (19, 20) arranged on the other bearing side, wherein one of the rolling element rings (7, 8) is supported on each of the bearing discs (19, 20).

Description

[0001] The invention relates to a double-row axial bearing.

[0002] Thrust bearings are used wherever axially adjacent components must be supported against one another in a rotatable manner. One example is disclosed in JP 2012 - 145 134 A. The thrust bearing is arranged axially in a planetary drive between a planet gear and a carrier web of a planet carrier. It has a bearing disk arranged on the planet carrier, a bearing disk arranged on a planet gear and on a radial bearing of the planet gear, and a rolling element ring arranged axially between the bearing disks and containing a plurality of roller-shaped rolling elements. The rolling elements are guided in a cage arranged between the bearing disks. The cage holds the rolling elements on a pitch circle radially at the level of the planet gear. Rolling elements are provided, which are often designed in the form of long needles or rollers and are accommodated and guided in a cage, with the longitudinal axes of the elongated rolling elements running towards the bearing center, i.e. the axis of rotation.Due to the cylindrical, elongated geometry of the rolling elements and their arrangement and alignment, slippage occurs when the rolling element ring formed by the rolling elements and the cage rotates. This means that the rolling element movement has a corresponding sliding component, which is undesirable and can lead to bearing damage. To counteract this, it is known to design an axial bearing as a double-row axial bearing with two radially nested rolling element rings, each of which has several needle- or roller-shaped rolling elements that are accommodated and guided in a respective cage. However, because they are nested, they necessarily have different diameters. This makes it possible, on the one hand, to use shorter needle- or roller-shaped rolling elements. On the other hand, it creates the option for the two rolling element rings to rotate at different orbital speeds, resulting in less slippage overall.The rolling element rings are axially supported on one side by a bearing disk of the axial bearing, which, for example, has a U-shaped cross-section and roll on this disk. If another bearing disk is used on the other side, on which the two rolling element rings also run, the advantage of reduced slippage resulting from the concentric arrangement of the rolling element rings is partially reduced. On the other side of the axial bearing, the rolling element rings run on separate rolling raceways, as disclosed in DE 10 2017 106 884 A1. The rolling raceway for the rolling elements of the radially outer rolling element ring is formed directly on a planetary gear, and the other on a cage rim of a radial bearing.

[0003] The invention is based on the object of providing a double-row axial bearing which is improved compared to the prior art.

[0004] The object is achieved according to the subject matter of claim 1. A double-row axial bearing is provided, comprising a bearing disc arranged on a bearing disc, U-shaped in cross section, and at least two rolling element rings running on this, arranged radially one inside the other, each comprising a plurality of needle- or roller-shaped rolling elements, wherein each rolling element ring runs on a separate further bearing disc arranged on the other bearing side.

[0005] In the row axial bearing according to the invention, a one-piece bearing disk with a U-shaped cross-section is provided on one side. This one-piece bearing disk, on which the two rolling element rings roll, can, for example, form the stationary bearing side. On the opposite bearing side, however, two separate annular bearing disks are provided, which are arranged radially one inside the other, i.e., concentrically like the rolling element rings, with one of the rolling element rings being supported or running on each bearing disk. This means that not only are the rolling elements divided into two separate rolling element rings, but also that the axial disk support is divided into two separate bearing disks on one side. This design makes it possible, on the one hand, to enable a relative speed between the two rolling element rings and, on the other hand, to ensure optimal axial support via a respective additional bearing disk on this side as well.

[0006] The inventive design of the double-row axial bearing makes it possible, with an appropriate geometric configuration or corresponding definition of the bearing disk diameter, to support a separate component on each of the two additional bearing disks. This means that each component only comes into contact with one additional bearing disk, so that the two components supported on it can ultimately rotate independently of one another. This means they can rotate at different speeds, and opposite directions of rotation are also conceivable. This is because, thanks to the invention, the two separate rolling element rings can rotate independently of one another on one side and roll on the shared, U-shaped bearing disk, while on the other bearing side, the two individual components are supported separately and axially as best as possible.Any slippage conditions are significantly reduced by the separation according to the invention both on the part of the rolling element rings and on the part of the separate additional bearing disks assigned to them, compared to a design in which one-piece bearing disks are provided on both sides.

[0007] In a further development of the invention, it can be provided that the one or two further bearing disks are connected in an axially self-retaining manner, but rotatable about the bearing axis, to a cage on which the rolling elements of a respective, associated rolling element race are held. Here, the axial securing of one or preferably of the two further bearing disks is achieved via a corresponding connection of the further bearing disk to the cage of the associated rolling element race. Since the two rolling element races, which are accommodated in the U-shaped bearing disk and are encompassed radially on the inside and outside by a corresponding disk leg, are usually already axially secured in the U-shaped bearing disk, a correspondingly closed bearing design can be realized by appropriate axial securing of the further bearing disks to the rolling element cages.

[0008] As an alternative to connecting one or two additional bearing discs to the cages, a further embodiment of the invention provides for one or both additional bearing discs to be connected to the U-shaped bearing disc in an axially self-retaining manner, yet rotatable about the bearing axis. This self-retaining connection, which still allows rotational movement, thus also creates a correspondingly closed, self-retaining bearing configuration, which is correspondingly easy to handle and install.

[0009] To achieve this axial self-retaining, it is conceivable for the or each additional bearing disc to be snapped onto either a locking shoulder of the respective cage or a lateral annular leg of the U-shaped bearing disc. Such a locking shoulder can be designed, for example, as a simple local indentation or as a circumferential annular shoulder. The design is arbitrary, as long as appropriate axial locking is implemented.

[0010] In a further development of the invention, the or each further bearing disc is expediently L-shaped in cross-section and is provided on an annular leg with one or more locking projections which engage behind the locking shoulder of the cage. The bearing disc is therefore provided with preferably several local locking projections, preferably on the cylindrical, axially extending leg, wherein these locking projections engage behind the preferably circumferential locking shoulder of the cage. The two further bearing discs are preferably designed such that the annular, axially extending leg of the inner bearing disc is provided on the outer circumference and the radially outer bearing disc is provided on the inner circumference, so that consequently the two axial annular legs are adjacent and virtually in the center of the bearing.This enables the axial securing of the respective cage to the U-shaped bearing disc in a simple manner, which, as described, encompasses or encloses the two cages axially on the outer and inner circumference and can also be axially secured there via corresponding locking projections.

[0011] As described, the double-row axial bearing according to the invention allows, among other things, the axial support or mounting of two separate, rotatable components on the side on which the two additional bearing discs are provided. One component is connected to one bearing disc, the other component to the other. As described, this allows the realization of different rotational speeds of the components as well as, if necessary, different directions of rotation. The design of the axial bearing makes it possible to respond to different requirements or geometric conditions within the assembled bearing arrangement. For example, it is possible for the rolling elements of one rolling element ring to have either the same or a different diameter than the rolling elements of the other rolling element ring.This means that ultimately the axial heights of the respective rolling element ring can be the same or different, meaning that the corresponding support planes can either be parallel or stepped relative to one another.

[0012] Alternatively or additionally, it is also conceivable for one rolling element ring to have the same number of or more rolling elements than the other. This means that a largely variable setting of the number of rolling elements in both rolling element boundaries is also possible independently of each other.

[0013] In addition to the double-row axial bearing itself, the invention further relates to a bearing arrangement, in particular in the form of or as part of a planetary gear, comprising at least one axial bearing of the type described above, wherein different components are rotatably mounted on the two further bearing disks. For example, one further bearing disk can axially support a planetary gear, while the other further bearing disk supports, for example, a sun gear or a cage. The opposite, one-piece U-shaped bearing disk is supported, for example, on a planet carrier. The use of such a bearing arrangement is not limited to planetary gears; rather, the axial bearing or the bearing arrangement can also be integrated into other drive or actuating drives, such as an electric parking brake.

[0014] The invention is explained below using exemplary embodiments with reference to the drawings. The drawings are schematic representations and show: Fig. 1 a perspective partial view of a double-row axial bearing according to the invention, and Fig. 2 a sectional view through the axial bearing from Fig. 1.

[0015] The Fig. 1 and Fig. 2 show different views of a double-row axial bearing 1 according to the invention, which is suitable, for example, for integration into a planetary gear. The axial bearing 1 has a U-shaped bearing disk 2 with a flat, radially extending leg 3 and two axially extending legs 4, 5 provided on the inner and outer circumferences. The leg 3 forms a running surface 6 for two separate rolling element races 7, 8, which are radially nested within one another and thus have correspondingly different diameters. The two legs 4, 5 serve to radially guide the two rolling element races 7, 8.

[0016] Each rolling element ring 7, 8 has a plurality of needle- or roller-shaped rolling elements 9, 10, which, in the example shown, have the same length and diameter. However, the length and / or diameter of the rolling elements 9, 10 can also vary, as can the number in each rolling element ring 7, 8.

[0017] Each rolling element ring 7, 8 further comprises a cage 11, 12 in or on which the respective rolling elements 9, 10 are received and guided in a manner known per se.

[0018] The cage 11 is constructed with two layers on its inner circumference, thus having a bent section 13, over which it is radially guided on the radially inner leg 4. On its outer circumference, the cage 11 has a locking shoulder 14 that extends radially and, as described below, serves to fix another bearing disk.

[0019] The radially outer cage 12 has a corresponding bent section 15 on its outer circumference, over which it is radially guided on the outer leg 5. Accordingly, it has a radially inwardly extending locking shoulder 16 on its inner circumference, which in turn serves to fix another bearing disk, which will be discussed below.

[0020] For the self-retaining of the rolling element rings 7, 8, corresponding locking sections 17, 18 which are bent radially inwards are provided on the legs 4, 5 and which slightly overlap the respective bending sections 13, 14 when viewed axially, so that the rolling element rings 7, 8 or cages 11, 12 snapped into the U-shaped bearing disc 2 cannot fall out of the bearing disc 2.

[0021] On the side opposite the U-shaped bearing disc 2, each rolling element ring 7, 8 is equipped with a separate additional bearing disc 19, 20, each of which has an L-shaped cross-section. Each bearing disc 19, 20 has a radially extending, disc-shaped leg 21, 22 and an axially extending leg 23, 24. On the radially inner additional bearing disc 19, the axially extending leg 23 is provided on the outer circumference, and on the radially outer additional bearing disc 20, the axially extending leg 24 is provided on the inner circumference. The two legs 21, 22 each form a running surface 25, 26 for the rolling elements 9, 10. This means that the rolling elements 9, 10 roll on the common running surface 6 of the U-shaped bearing disc 2, but on separate running surfaces 25, 26 of the other bearing discs 19, 20.This allows the rolling element rings 7, 8 to rotate at different speeds and even in different directions of rotation, provided a separate component is supported on each additional bearing disc 19, 20, allowing both components to rotate independently of each other. This is useful when used in a planetary gear.

[0022] In order to be able to fasten the other bearing discs 19, 20 in a self-retaining manner, several locally bent locking projections 27, 28 are provided on the axial legs 23, 24, which engage behind the corresponding locking shoulder 14, 16 of the respective cages 11, 12, as in particular Fig. 2 clearly shows. Consequently, the two additional bearing discs 19, 20 are also held captively, so that the axial bearing 1 as a whole is a self-retaining unit. List of reference symbols 1 thrust bearing 2 bearing discs 3 radial leg 4 axial leg 5 axial leg 6 Tread 7 Rolling element ring 8 Rolling element ring 9 rolling elements 10 rolling elements 11 Cage 12 cages 13 Bending section 14 locking shoulder 15 Bending section 16 locking shoulder 17 Rest section 18 rest section 19 Bearing disc 20 bearing disc 21 Radially extending leg 22 radially extending leg 23 axially extending leg 24 axially extending leg 25 tread 26 Tread 27 locking projection 28 locking projection

Claims

[1] Double-row axial bearing, comprising a bearing disc (2) arranged on one bearing side, U-shaped in cross-section, and at least two rolling element rings (7, 8) running on this, arranged radially one inside the other, the rolling element rings (7, 8) each comprising a plurality of needle- or roller-shaped rolling elements (9, 10), wherein at least one of the rolling element rings (7, 8) runs on a separate further bearing disc (19, 20) arranged on the other bearing side, characterized by that each rolling element ring (7, 8) runs on a separate further bearing disc (19, 20) arranged on the other bearing side, wherein one of the rolling element rings (7, 8) is supported on each of the bearing discs (19, 20). [2] Double-row axial bearing according to claim 1, characterized bythat one or both further bearing discs (19, 20) are connected in an axially self-retaining manner but rotatable about the bearing axis either to a cage (11, 12) on which the rolling elements (9, 10) of a rolling element ring (7, 8) are held, or to the U-shaped bearing disc (2). [3] Double-row axial bearing according to claim 2, characterized by that one or each further bearing disc (19, 20) is snapped either onto a locking shoulder (14, 16) of the respective cage (11, 12) or onto a lateral annular leg (4, 5) of the U-shaped bearing disc (2). [4] Double-row axial bearing according to claim 3, characterized by that one or each further bearing disc (19, 20) is L-shaped in cross-section and is provided on an annular leg (23, 24) with one or more locking projections (27, 28) which engage behind the locking shoulder (14, 16) of the cage (11, 12). [5] Double-row axial bearing according to claim 4, characterized bythat the annular leg (23) of the radially inner further bearing disc (19) is provided on its outer circumference and the annular leg (24) of the radially outer further bearing disc (20) is provided on its inner circumference, and that the annular legs (4, 5) of the U-shaped bearing disc (2) are each provided with one or more locking projections (17, 18) axially overlapping the adjacent cage (11, 12). [6] Double-row axial bearing according to one of the preceding claims, characterized by that the rolling elements (9) of one rolling element ring (7) have the same or a different diameter than the rolling elements (10) of the other rolling element ring (8). [7] Double-row axial bearing according to one of the preceding claims, characterized by that one rolling element ring (7) has the same number or more rolling elements (9) than the other rolling element ring (8). [8] Bearing arrangement, in particular in the form of or as part of a planetary gear, comprising at least one double-row axial bearing (1) according to one of the preceding claims, wherein different components are rotatably mounted on the two further bearing discs (19, 20).

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