Rolling bearings, tripod rollers with rolling bearings, and methods for manufacturing a rolling bearing

Abstract

The invention relates to a rolling bearing (10) with an inner ring (12) and an outer ring (14) as well as a plurality of rolling elements (16, 30, 32, 34) arranged between the inner ring (12) and the outer ring (14) as well as a plurality of load segments (36, 38, 40) arranged between the inner ring (12) and the outer ring (14). The rolling elements (16, 30, 32, 34) have a slightly larger dimension in the radial direction than the load segments (36, 38, 40), such that the rolling elements (16, 30, 32, 34) roll on the inner ring (12) and the outer ring (14) in an unloaded or slightly loaded operating condition and, in the event of a sudden or impact load on the rolling bearing (10), the forces acting on the rolling elements (16, 30, 32, 34) are limited by the fact that the sudden or impact load is absorbed at least partially by the load segments (36, 38, 40). The invention further relates to a tridope roller (60) for a tripod joint (62) with such a rolling bearing (10) and a method for manufacturing such a rolling bearing (10).

Description

[0001] The invention relates to a rolling bearing, a tripod roller with such a rolling bearing and a method for producing a rolling bearing according to the preamble of the independent patent claims.

[0002] Different types of bearings, particularly plain bearings and rolling bearings, are known for supporting rotatably mounted components. While rolling bearings enable low-friction rotation of a rotating component even upon start-up, plain bearings require an appropriate lubricating film to first build up between the rotating component and the bearing. This can lead to increased friction and increased wear, particularly during start-up. While plain bearings have a damping component due to the hydrodynamic effect between the rotating component and the bearing, impacts or shocks in a rolling bearing immediately lead to high mechanical stress on the rolling elements and the raceways on which the rolling elements roll. In addition to rolling bearings and plain bearings, hybrid bearings are also known, which exhibit aspects of both a rolling bearing and a plain bearing.

[0003] For example, DE 43 27 543 C2 discloses a sliding roller bearing comprising an outer cylinder, an inner cylinder, and a plurality of, preferably cylindrical, rolling elements. The inner cylinder has a plurality of axially extending receiving grooves in its outer circumferential surface for receiving the rolling elements. The rolling elements are in sliding contact with the inner cylinder and in rolling contact with the outer cylinder.It is provided that the receiving grooves have radially inner regions with substantially semicircular cross-sections and radially outer regions with substantially sector-shaped cross-sections diverging radially outwards, and that the inner diameter of the outer cylinder and the largest outer diameter of the inner cylinder are dimensioned such that an outer circumferential surface of the inner cylinder remaining between the receiving grooves comes into sliding contact with the inner surface of the outer cylinder as the load increases.

[0004] From DE 23 17 592 A1 an axial rolling bearing is known in which a plurality of sliding elements are additionally arranged in the cage in order to avoid plastic deformation of the rolling bearing running surfaces as a result of axial load impacts, the dimensions of which in the axial direction are somewhat smaller than the diameter of the rolling elements, so that the sliding elements with their large surface area compared to the rolling elements only contact the rolling bearing running surfaces when axial load impacts occur and because of the elastic deformability of the rolling bearing running surfaces, before their elastic deformation can change into plastic deformation.

[0005] The invention is based on the object of increasing the load capacity of a rolling bearing against a shock or impact movement and of overcoming the disadvantages known from the prior art.

[0006] This problem is solved by a rolling bearing with an inner ring and an outer ring, as well as a plurality of rolling elements arranged between the inner ring and the outer ring, and a plurality of load segments arranged between the inner ring and the outer ring. The rolling elements have slightly larger dimensions in the radial direction than the load segments, such that the rolling elements roll against the inner ring and the outer ring in an unloaded or lightly loaded operating state. In the event of an abrupt or shock load on the rolling bearing, the forces acting on the rolling elements are limited by the load segments at least partially absorbing the abrupt or shock load. The load segments provide better protection for the rolling bearing during load peaks, allowing it to withstand significantly higher loads for a given size.In this context, a low-load condition is understood to mean an operating condition in which the rolling bearing is loaded with a maximum of 20%, preferably a maximum of 10%, of its permissible load capacity.

[0007] To lubricate the rolling bearing, a grease containing a solid lubricant such as MoS2 (molybdenum disulfide) is preferably used. Such a grease with a solid lubricant is advantageous because it improves the wear and emergency running properties of the rolling bearing. Furthermore, such a grease with a solid lubricant is advantageous because it can improve the smooth running of the rolling elements in the bearing. Another advantage of such a grease is that when used in a tripod joint, no liquid lubricant leaks from the rolling bearing.

[0008] The features listed in the dependent claims enable advantageous further developments and improvements of the rolling bearing mentioned in the independent claim.

[0009] The rolling elements and load segments are preferably arranged in a periodically repeating sequence between the inner and outer rings. This achieves a particularly uniform load distribution in the rolling bearing. For example, two adjacent rolling elements can alternate with one load segment each, resulting in the following repeating sequence: (rolling element-rolling element-load segment-) n , where n is the number of repetitions. Conversely, two adjacent load segments can alternate with one rolling element each, resulting in the following repetition sequence (rolling element-load segment-load segment-) n. Preferably, the rolling elements and the load segments are arranged alternately between the inner ring and the outer ring, so that the following repetition sequence results (rolling element-load segment-) n .

[0010] In a preferred embodiment of the invention, the radial expansion of the rolling elements is 2 µm to 800 µm, preferably 5 µm to 200 µm, greater than the radial expansion of the load segments. This allows the rolling elements to roll against the inner and outer rings in an unloaded or lightly loaded operating state. However, at higher loads and load peaks, the load segments absorb part of the force and thus protect the rolling bearing. The magnitude of the difference in radial expansion between the rolling elements and the load segment can be adapted to the requirements and the size of the rolling bearing. By means of a size difference in the range of 2 µm to 800 µm, in particular in the range of 5 µm to 200 µm, it can be ensured that the load segments absorb at least part of the load before plastic deformation of one of the raceways for the rolling elements of the rolling bearing occurs.The range is selected so that elastic deformation of the inner ring and / or the outer ring results in the load segments being able to absorb the load peaks caused by an impact or shock.

[0011] In a further preferred embodiment of the invention, the load segments have a pressure build-up area for building up a load-bearing lubricating film between the load segment and the inner ring and / or the outer ring, and a main load-bearing area for absorbing a load. This improves the formation of a lubricating film between the load segment and the inner ring or the outer ring of the rolling bearing, so that the load segment floats on the lubricating film like a plain bearing, and friction in the rolling bearing is reduced. The pressure build-up area ensures that, upon relative rotation of the inner ring to the outer ring, the lubricant is pumped into the gap between the load segment and the corresponding ring of the rolling bearing. The main load-bearing area then forms a thin gap in the range of 2 µm to 500 µm, so that the main load-bearing area can absorb a corresponding load on the rolling bearing and relieves the load on the rolling elements.

[0012] In a further preferred embodiment of the invention, the load segments are moved by the rolling elements during relative rotation of the inner ring to the outer ring, such that a lubricating film forms between the load segment and the inner ring and / or the outer ring. The formation of a lubricating film allows the bearing to run more smoothly, generating less frictional heat. This can increase the service life of such a rolling bearing and reduce the probability of failure.

[0013] In a further preferred embodiment of the invention, all load segments and / or all rolling elements are identical. The use of identical parts can reduce manufacturing costs and eliminate a source of error during assembly of the rolling bearing. Furthermore, the use of identical load segments and rolling elements guarantees reliable operation without jamming.

[0014] In a further preferred embodiment of the invention, the rolling elements are designed as needles. The use of needles as rolling elements enables a particularly compact design of the rolling bearing. Furthermore, needles have the advantage over balls in that they can bear a high radial load due to their linear force transmission surface.

[0015] In a further preferred embodiment of the invention, the load segments are manufactured as sintered components or by profile drawing and subsequent cutting. Manufacturing as a sintered component proves particularly advantageous in terms of shape design, emergency running properties, cost, and process simplicity. Alternatively, a profile can be drawn, from which the load segments can be cut from a profile bar using a simple cutting process. This also enables comparatively simple and cost-effective production of the load segments.

[0016] The rolling bearing is designed in a modular manner so that it can be adapted to the specific requirements of the rolling bearing. The rolling bearing is equipped with rolling elements and load segments according to the expected requirements of the rolling bearing. In particular, requirements regarding the bearing's load capacity, resistance to shocks or impacts, decoupling behavior, and other parameters can be taken into account.

[0017] A further aspect of the invention relates to a tripod roller for a tripod joint, which contains a rolling bearing as described in the previous sections. The tripod roller comprises an outer ring having a surface that is curved outward in the radial direction. Such a tripod roller enables a particularly simple and cost-effective mounting of a drive shaft.

[0018] In a preferred embodiment of the invention, the tripod joint comprises a plurality of tripod rollers described in the previous section, with rolling surfaces for the outer rings of the tripod rollers being formed on a housing of the tripod joint. Such a tripod joint enables comfortable mounting of a drive shaft in a transmission output of a transmission, in particular an automatic transmission. In this context, an automatic transmission refers to all transmission types that enable gear shifting without manual intervention by the driver, in particular automatic transmissions in the form of a torque converter transmission or an automated dual-clutch transmission.

[0019] In a further advantageous embodiment of the rolling bearing, the inner ring is designed as a solid body. Such a solid body is particularly stable and can absorb and transmit correspondingly high forces. The solid body is preferably designed in the shape of a cylinder.

[0020] A further aspect of the invention relates to a method for producing a rolling bearing, which comprises the following steps: - Manufacturing of an inner ring and an outer ring, - Manufacturing of rolling elements, - Manufacturing load segments, - alternating arrangement of rolling elements and load segments between the inner ring and the outer ring, such that - the rolling elements roll on the inner ring and the outer ring in an unloaded operating condition and in the event of an abrupt or shock load on the rolling bearing, the forces acting on the rolling elements are limited by the abrupt or shock load being absorbed at least partially by the load segments.

[0021] To secure the rolling elements and load segments in the rolling bearing, locking elements can be provided on one or both sides. These are fixed to the outer or inner ring of the rolling bearing. Furthermore, the rolling bearing can be lubricated, particularly with a grease containing solid lubricants such as MoS2 (molybdenum disulfide).

[0022] The method enables a simple and cost-effective production of a rolling bearing which, compared to rolling bearings known from the prior art, has a higher load capacity against a shock or impact movement and at least partially overcomes the disadvantages known from the prior art.

[0023] The various embodiments of the invention mentioned in this application can be advantageously combined with one another, unless otherwise stated in the individual case.

[0024] The invention is explained below in exemplary embodiments with reference to the accompanying drawings. They show: Fig. 1 a tripod roller known from the prior art with a rolling bearing which is designed as a needle bearing, Fig. 2 another illustration of a tripod roller with a corresponding force acting on the inner ring, Fig. 3 a tripod joint according to the invention from a shaft connection side, Fig. 4 a preferred embodiment of a rolling bearing according to the invention, Fig. 5 shows a further preferred embodiment of a rolling bearing according to the invention, Fig. 6 shows a further preferred embodiment of a rolling bearing according to the invention, Fig. 7 shows a further preferred embodiment of a rolling bearing according to the invention, Fig. 8 a preferred embodiment of a tripod scooter according to the invention, Fig. 9 shows a further preferred embodiment of a tripod scooter according to the invention, Fig. 10 a preferred embodiment of a load segment and Fig. 11 a flow chart for producing a rolling bearing according to the invention.

[0025] Fig. Figure 1 shows a prior art tripod roller 60 with a roller bearing 10 designed as a needle bearing. The roller bearing 10 comprises an inner ring 12 and an outer ring 14 with an outwardly curved surface 58. Between the inner ring 12 and the outer ring 14 are a plurality of rolling elements 16, designed as needles 24, which enable relative movement between the inner ring 12 and the outer ring 14. Furthermore, the rolling elements 16 are secured laterally on both sides by a retaining ring 26.

[0026] Fig. 2 shows a further illustration of a tripod roller 60 with a corresponding force acting on the inner ring 12. The rolling bearing 10 comprises an inner ring 12 and an outer ring 14 with an outwardly curved surface 58. Between the inner ring 12 and the outer ring 14, a plurality of rolling elements 16 are arranged, which are designed as needles 24 and enable a relative movement between the inner ring 12 and the outer ring 14. As in Fig. 2, a force F1 acting on the inner ring 12 is transmitted to the outer ring 14 by the rolling elements 16.

[0027] Fig. 3 shows an open joint side 66 of a tripod joint 62 according to the invention from a shaft connection side for connecting a drive shaft 68, wherein the tripod joint 62 comprises three tripod rollers 60. On the side of the drive shaft 68, which is received and rotatably mounted in a tripod joint piece 64 by the tripod joint 62, a tripod star with a toothing 70 is formed in the tripod joint 62, via which a drive torque is transmitted to the drive shaft 68. The tripod joint 62 ensures a uniform rotational movement and compensates for movements of the vehicle suspension as well as shocks and impacts acting on the drive train, in particular due to uneven road surfaces.

[0028] In Fig. Figure 4 shows a preferred embodiment of a rolling bearing 10 according to the invention. The rolling bearing 10 has an inner ring 12 and an outer ring 14 as well as a plurality of rolling elements 16, 30, 32, 34, which can be designed as a ball 20, cylinder 22, or needle 24. Furthermore, the rolling elements can be provided with a coating 28 to reduce friction. The rolling bearing 10 according to the invention also has a plurality of load segments 36, 38, 40, which are arranged between the inner ring 12 and the outer ring 14. A raceway for the rolling elements 16 is formed on each of the inner ring 12 and the outer ring 14. Furthermore, a lubricant 18 is introduced into the gap between the inner ring 12 and the outer ring 14 to minimize the friction of the rolling elements.This lubricant 18 also supports the load segments 36, 38, 40 when the inner ring 12 rotates relative to the outer ring 14. Above a defined rotational speed or rotational velocity, the load segments float on a lubricating film like a plain bearing. The rolling bearing 10 is designed such that each load segment 36, 38, 40 is alternately followed by exactly one rolling element 16, and vice versa. The radial expansion of the rolling elements 16, 30, 32, 34 is 2 µm to 800 µm greater than the radial expansion of the load segments 36, 38, 40. Generally, a design with three or a multiple of three rolling elements 16 is preferred, although other designs are also possible.

[0029] Fig. 5 shows a further preferred embodiment of a rolling bearing 10 according to the invention, wherein the rolling bearing 10 has an inner ring 12, an outer ring 14, as well as three rolling elements 16, 30, 32, 34, and three load segments 36, 38, 40, which are arranged between the inner ring 12 and the outer ring 14. The rolling elements 16, 30, 32, 34 and load segments 36, 38, 40 are arranged alternately such that the first rolling element 16, 30 is followed by the first load segment 36, then the second rolling element 16, 32 and the second load segment 38, and finally the third rolling element 16, 34 and the third load segment 40, all of which are lubricated with a lubricant 18.

[0030] Fig. 6 shows a further preferred embodiment of a rolling bearing 10 according to the invention, wherein the rolling bearing 10 has an inner ring 12 and an outer ring 14. Between the inner ring 12 and the outer ring 14, the rolling elements 16 and load segments 36a, 36b, 38a, 38b, 40a, 40b are arranged alternately such that the first rolling element 16, 30 is followed by the first load segment 36a and a second identical load segment 36b, then by the second rolling element 16, 32 and the second load segment 38a and an identical load segment 38b, and finally by the third rolling element 16, 34 and the third load segment 40a and a second identical load segment 40b. In this embodiment, a rolling element 16 is followed by two identical load segments 36, 38, 40 on each rolling element 16, 30, 32, 34, whereby the length of the load segments 36, 38, 40 can be shortened.

[0031] Fig. 7 shows a further preferred application example for a rolling bearing 10 according to the invention. The rolling bearing 10 has an inner ring 12 and an outer ring 14 as well as four rolling elements 16, 30, 32, 34, 74 and four load segments 36, 38, 40, 76, which are arranged between the inner ring 12 and the outer ring 14. The rolling elements 16 and load segments 36, 38, 40 are arranged alternately such that the first rolling element 16, 30 is followed by the first load segment 36, then the second rolling element 16, 32 and the second load segment 38, then the third rolling element 16, 34 and the third load segment 40, and finally the fourth rolling element 74 and the fourth load segment 76.

[0032] In Fig. Figure 8 shows a preferred embodiment of a tripod roller 60 according to the invention, wherein the tripod roller 60 has an inner ring 12 and an outer ring 14 with an outwardly curved surface 58, as well as a plurality of rolling elements 16, 30, 32, 34, 74 and load segments 36, 38, 40, 76 arranged between the inner ring 12 and the outer ring 14. The rolling elements 16 and the load segments 36, 38, 40, 76 are arranged alternately and lubricated with a lubricant 18. The load segments 36, 38, 40, 76 have slightly more play than the rolling elements 16, whereby at low loads only the rolling elements 16, but at high loads all elements, carry the load in the direction of the load. The load segments 36, 38, 40, 76 are designed here as a rectangle with rounded corners, which promotes the formation of a lubricating film 56 between the load segments 36, 38, 40, 76 and the inner ring 12.The rolling elements 16 ensure movement of the load segments 36, 38, 40, 76 through their rotation, whereby additional grease is pumped into the gap between the load segment 36, 38, 40, 76 and the inner ring 12 for a rapid build-up of lubrication pressure.

[0033] In Fig. Figure 9 shows a further preferred embodiment of a tripod roller 60 according to the invention, wherein the tripod roller 60 has an inner ring 12 and an outer ring 14 with an outwardly curved surface 58, as well as a plurality of rolling elements 16, 30, 32, 34, 74 and load segments 36, 38, 40, 76 arranged between the inner ring 12 and the outer ring 14. The rolling elements 16 and the load segments 36, 38, 40, 76 are arranged alternately and lubricated with a lubricant 18. The load segments 36, 38, 40, 76 have slightly more play than the rolling elements 16, whereby at low loads only the rolling elements 16, but at high loads all elements, carry the load in the direction of the load. The rolling elements 16 ensure, through their rotation, an optimal lubrication pressure build-up on the load segments 36, 38, 40, 76.The load segments 36, 38, 40, 76 are designed here in a substantially rectangular shape, with the load segments 36, 38, 40, 76 each having a receiving area for a rolling element 16, 30, 32, 34, 74 on their end faces. In general, the detailed design of the load segments 36, 38, 40, 76 can be used to specifically influence the desired properties of the rolling bearing 10.

[0034] Fig. 10 shows a preferred embodiment of a load segment 36. The load segment 36 consists of a central section 46, which has a main support area 50 and a pressure amplification area 52, and two symmetrical edge sections 42, 44 to the left and right of the central section 46, which serve as pressure build-up areas 48 and whose left and right end faces form a rolling element receiving area 54. Fig. 10 shows a direction of movement in which the load segment 36 moves when the rolling bearing 10 rotates.

[0035] In Fig. Figure 11 shows the step-by-step production of a rolling bearing according to the invention.

[0036] In one manufacturing step <100> inner ring 12 and outer ring 14 are manufactured. In a further manufacturing step <110> Rolling elements 16, 30, 32, 34, 74 are manufactured, which can be made of steel, cast iron, plastic, sintered material, ceramic, and other materials depending on the requirements. In the next production step <120> Load segments 36, 38, 40, 76 are manufactured, whereby these are preferably produced as sintered components or by profile drawing and subsequent cutting.In a further production step <130> the rolling elements 16, 30, 32, 34, 74 and load segments 36, 38, 40, 76 are arranged alternately between the inner ring 12 and the outer ring 14, such that in a further manufacturing step <140> The rolling elements 16, 30, 32, 34, 74 roll on the inner ring 12 and the outer ring 14 in an unloaded operating state, and in the event of a sudden or impact load on the rolling bearing 10, the forces acting on the rolling elements 16, 30, 32, 34, 74 are limited by the sudden or impact load being at least partially absorbed by the load segments 36, 38, 40, 76. In a further manufacturing step, retaining rings can be placed on one or both sides to secure the rolling elements 16, 30, 32, 34, 74 and the load segments 36, 38, 40, 76 in the rolling bearing 10.Furthermore, in a further manufacturing step, lubrication or greasing of the rolling bearing 10 can be provided in order to minimize the friction in the rolling bearing 10. List of reference symbols 10 rolling bearings 12 inner ring 14 Outer ring 16 rolling elements 18 Lubricants 20 balls 22 cylinders 24 needle 26 Retaining ring 28 Coating 30 first rolling element 32 second rolling element 34 third rolling element 36 first load segment 38 second load segment 40 third load segment 42 first edge section 44 second edge section 46 Middle section 48 Pressure build-up area 50 main carrying area 52 pressure boost range 54 Rolling element receiving area 56 Lubricating film 58 Surface 60 tripod scooters 62 tripod joint 64 tripod joint piece 66 open joint side 68 Connection for drive shaft 70 gearing 72 rolling surface 74 fourth rolling element 76 fourth load segment 100 first procedural step 110 second procedural step 120 third procedural step 130 fourth procedural step 140 fifth procedural step F1 Power QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 43 27 543 C2

[0003] DE 23 17 592 A1

[0004]

Claims

[1] Rolling bearing (10) with an inner ring (12) and an outer ring (14) and a plurality of rolling elements (16, 30, 32, 34) arranged between the inner ring (12) and the outer ring (14) and a plurality of load segments (36, 38, 40) arranged between the inner ring (12) and the outer ring (14), wherein the rolling elements (16, 30, 32, 34) have a slightly larger dimension in the radial direction than the load segments (36, 38, 40), such that the rolling elements (16, 30, 32, 34) roll on the inner ring (12) and the outer ring (14) in an unloaded or slightly loaded operating state and in the event of an abrupt or shock-like load on the rolling bearing (10), the forces acting on the rolling elements (16, 30, 32, 34) acting forces are limited by the sudden or impact load being absorbed at least partially by the load segments (36, 38, 40). [2] Rolling bearing (10) according to claim 1, wherein the extension of the rolling elements (16, 30, 32, 34) in the radial direction is 2 µm to 800 µm greater than the radial extension of the load segments (36, 38, 40). [3] Rolling bearing (10) according to claim 1 or 2, wherein the load segments (36, 38, 40) have a pressure build-up area (48) for building up a supporting lubricating film (56) between the load segment (36, 38, 40) and the inner ring (12) and / or the outer ring (14) and a main support area (50) for receiving a load. [4] Rolling bearing (10) according to one of claims 1 to 3, wherein the load segments (36, 38, 40) are moved by the rolling elements (16, 30, 32, 34) during a relative rotation of the inner ring (12) to the outer ring (14) in such a way that a lubricating film (56) builds up between the load segment (36, 38, 40) and the inner ring (12) and / or the outer ring (14). [5] Rolling bearing (10) according to one of claims 1 to 4, wherein all load segments (36, 38, 40) and / or all rolling elements (16, 30, 32, 34) are the same. [6] Rolling bearing (10) according to one of claims 1 to 5, wherein the rolling bodies (16, 30, 32, 34) are designed as needles (24). [7] Rolling bearing (10) according to one of claims 1 to 6, wherein the load segments (36, 38, 40) are produced as sintered components or by profile drawing and subsequent cutting. [8] Tripod roller (60) for a tripod joint (62), comprising a rolling bearing (10) according to one of claims 1 to 7, wherein the tripod roller (60) comprises an outer ring (14) which has a surface (58) curved outwards in the radial direction. [9] Tripod joint (62) comprising a plurality of tripod rollers (60) according to claim 8, wherein rolling surfaces for the outer rings (14) of the tripod rollers (60) are formed on a housing of the tripod joint (62). [10] Method for producing a rolling bearing, comprising the following steps: - producing (100) an inner ring (12) and an outer ring (14), - manufacturing (110) of rolling elements (16, 30, 32, 34), - Manufacturing (120) of load segments (36, 38, 40), - Arrangement (130) of rolling elements (16, 30, 32, 34) and load segments (36, 38, 40) between the inner ring (12) and the outer ring (14), such that - (140) the rolling elements (16, 30, 32, 34) roll on the inner ring (12) and the outer ring (14) in an unloaded operating state and, in the event of an abrupt or shock-like load on the rolling bearing (10), the forces acting on the rolling elements (16, 30, 32, 34) are limited by the abrupt or shock-like load being absorbed at least partially by the load segments (36, 38, 40).

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