DE102011009219A1 - Tripod joint for transferring torque from driven end on bearing end shaft, has inner joint part and outer joint part, where rolling element track is designed in running direction of rolling bodies - Google Patents

Abstract

The tripod joint has an inner joint part and an outer joint part. A rolling element track (3) is designed in running direction (5) of rolling bodies in such a manner that a distance of the rolling element track is not constant from corresponding opposing straight track of the outer joint part over entire rolling element tracks. The distance is increases to two ends of the rolling element track.

Description

The present invention relates to a tripod joint comprising an inner joint part and an outer joint part, wherein the inner joint part comprises a tripod star with pins and the Tripodestern associated rolling elements, wherein the rolling elements each have a housing and a receiving opening configured therein for supporting a pin and at least one Wälzkörperlaufbahn, and each rolling element track of the housing associated rolling elements for support to corresponding, the Wälzkörperlaufbahnen the housing opposite, straight raceways of the outer joint part of the tripod joint.

Through tripod joints, it is possible to transmit a torque from a driving to a driven shaft. The axes of the shaft can thereby include an obtuse angle to each other through the use of Tripodegelenken. A tripod joint has an inner joint part and an outer joint part, wherein each part is in each case connected to one of the two shafts. The inner joint part of a Tripodegelenkes comprises a tripod star with pins and the Tripodestern associated rolling elements. The rolling elements each have a housing and a receiving opening configured therein for supporting a journal and at least one rolling body raceway. Rolling bodies, for example needles or balls, run on the rolling body raceway of a housing of a rolling element. The rolling elements are also located on one of the raceways of the outer joint part. The rolling elements thereby convey the power transmission between the two shafts. That is, the rolling elements of a rolling element abut both on the rolling body of the rolling element and on one of the raceways of the outer joint parts. There is often a certain production-related distance between the rolling elements of the rolling elements and the raceways of the outer joint part of the tripod joint. Thus, the rolling elements are not permanently on the raceways of the outer joint part of the tripod joint. This can lead to a noise, in particular when changing the direction of rotation of the driving shaft. The rolling body of the rolling elements and the raceways of the outer joint part of the tripod joint usually run parallel to each other. The rolling elements used are all the same size. However, it has proven to be disadvantageous in such tripod joints that the greatest wear in the rolling body rolling region is that of the middle rolling bodies, in particular the middle ball (s). The rolling elements of such tripod joints are usually held by Wälzkörperkäfige. The position of the rolling elements is dependent on the position of a Wälzkörperkäfigs. By micro-pulses, the Wälzkörperkäfige can leave their theoretical zero position in such Tripodegelenken, whereby the wear and thus the life of the Wälzkörperlaufbahnen the housing of the rolling elements and the raceways of the outer joint parts are adversely affected. This in turn leads to an increase in the noise level of the tripod joint.

The object of the invention is to provide a tripod joint, which is very robust, which has a high load capacity and the good acoustic properties.

This object is achieved by a tripod joint according to claim 1. Further features and details of the invention will become apparent from the dependent claims, the description and the drawings.

That is, according to the invention, the object is achieved by a tripod joint comprising an inner joint part and an outer joint part, wherein the inner joint part comprises a tripod star with pins and the Tripodestern associated rolling elements, wherein the rolling elements each have a housing and a receiving opening therein for supporting a pin and At least one of the Wälzkörperlaufbahnen in the running direction of the rolling elements is designed such that the distance between the at least one Wälzkörperlaufbahn from the corresponding, opposite straight track of the outer joint part is not constant over the entire Wälzkörperlaufbahn and at both ends of the at least one Wälzkörperlaufb increases, solved.

Such a tripod joint is very robust in comparison to known Tripodegelenken and it has a high load capacity and good acoustic properties. That is, the special different distance between the at least one Wälzkörperlaufbahn to the corresponding opposite straight track of the outer joint part of the tripod joint is very robust, can be heavily loaded and is relatively quiet. The special shape of the at least one rolling body raceway of the housing of a rolling element enables accurate positioning of the rolling elements between the at least one rolling body raceway and the raceway of the outer joint part of the tripod joint. Due to the special shape of the at least one rolling body raceway or by the specific distance of the at least one rolling body track to the corresponding raceway of the outer joint part of the tripod joint is ensured that the Wälzkörperkäfig, the rolling elements holds a rolling element, its initial position, that is, its zero position, permanently maintained. That is, the Wälzkörperkäfig returns again to its original position. Such a trained Tripodegelenk is particularly robust and resilient than Tripodegelenke same size.

In such a trained Tripodegelenk the outer rolling elements between a rolling body of the housing of a rolling element and a corresponding, opposite straight track of the outer joint part are formed larger than the or the inner (s) rolling elements. As a result, an improved pressure distribution, in particular uniform pressure distribution over the entire Wälzkörperlaufbahn guaranteed. Furthermore, a centering force can be generated on the roller body holding Wälzkörperkäfig by the use of larger outer rolling elements. That is, the Wälzkörperkäfig a rolling element returns due to the special positioning of the rolling elements between a Wälzkörperlaufbahn the inner joint part and a raceway of the outer joint part of the tripod joint always back to its zero position. As a result, the pressure distribution over the entire length of the rolling body raceway of a housing of a rolling element can always be kept the same. This leads to improved acoustic properties of the Tripodegelenkes, a lower wear and thus to a higher robustness and resilience of the Tripodegelenkes. The rolling elements may be formed as needles. Furthermore, the rolling elements may be barrel-shaped, conical or cylindrical. Preferably, the rolling elements are designed as balls.

According to a preferred development of the invention can be provided in the tripod joint, that the distance of the at least one Wälzkörperlaufbahn of the corresponding opposite straight track of the outer joint part to both ends of the at least one Wälzkörperlaufbahn by a respective convex curved, a circular segment-shaped or a linear course of at least a Wälzkörperlaufbahn increases. Such a profile of the at least one rolling body track ensures that the outer rolling elements can be made larger than the one or more inner rolling elements. Furthermore, such a course of the at least one rolling body raceway and the associated different size of the rolling bodies of a rolling body raceway ensures that the rolling body cage holding the rolling bodies does not slip out of its zero position due to micro-pulses. The Wälzkörperkäfig and thus the rolling elements center themselves again and again. This results in an always equal pressure distribution of all rolling elements result, which in turn ensures low wear and low acoustic interference. All embodiments of the at least one rolling element rolling track have in common that the distance at the ends of the at least one rolling body track to the corresponding, opposite straight track of the outer joint part is greater than in the central region of the at least one Wälzkörperlaufbahn.

At least one rolling body track is provided per rolling element. That is, in a tripod joint at least three Wälzkörperlaufbahnen are present. Each rolling element track is associated with a corresponding straight track of the outer joint part.

The at least one Wälzkörperlaufbahn may be formed so that in the middle of at least one Wälzkörperlaufbahn the distance to the corresponding, opposite straight track of the outer joint part is least and starting from the center of the at least one Wälzkörperlaufbahn to the end of at least one Wälzkörperlaufbahn increases. The increase in the distance may be uniform, but not uniform. According to a particularly preferred development of the invention may be provided in the tripod joint, that in a central portion of the at least one Wälzkörperlaufbahn a straight region is provided in which the distance of the at least one Wälzkörperlaufbahn of the corresponding, opposite straight track of the outer joint part is constant. The distance of the at least one Wälzkörperlaufbahn to the corresponding, opposite straight track of the outer joint part is larger starting from the ends of the central straight portion to the ends of the at least one Wälzkörperlaufbahn. As a result, it is also ensured in this embodiment of the tripod joint, in particular by the different size of the rolling elements, that the rolling element cage holding the rolling elements always returns to its initial position. That is, the rolling elements provide by their position between the at least one rolling element of the rolling element body of a rolling element to a corresponding, opposite straight track of the outer joint part for centering of the Wälzkörperkäfigs. By centering the Wälzkörperkäfigs an improvement of the Tripodegelenkes is given in terms of wear, durability, acoustic requirements and robustness.

Preference is given to a tripod joint in which inlet regions in the form of rounding, folds or chamfers are provided at the ends of the at least one rolling body raceway.

According to a particularly preferred development of the invention may be provided in the tripod joint that the at least one rolling element raceway and / or at least a Wälzkörperlaufbahn corresponding, opposite straight track of the outer joint part of the Tripodegelenkes has a Gothic track shape / have. In particular, a tripod joint is preferred in which the Wälzkörperlaufbahnen the inner joint part of the tripod joint and the straight raceways of the outer joint part of the tripod joint each have Gothic track shapes. Such a trained career of the outer joint part has two parallel profiles. The rolling element raceways are also characterized by two identical, mutually parallel profiles. Particularly preferably, a rolling body track on two circular arc-shaped profiles. The rolling elements, which are arranged between a rolling body raceway of the inner joint part and a raceway of the outer joint part, contact each of the two raceways, that is, the straight raceway of the outer joint part and the Wälzkörperlaufbahn the inner joint part, respectively at two points. Such gothic raceway profiles ensure that the rolling elements are securely centered between the raceways. The Gothic profiles of a Wälzkörperlaufbahn are each designed such that the distance between each of the two profiles of gothic trained Wälzkörperlaufbahn of the corresponding opposite straight track of the outer joint part is not constant over the entire length of each profile and increases to both ends of each profile , wherein the two profiles are identical. Such trained tripod joint is not susceptible to wear, has a long service life, is very robust and at the same time extremely quiet compared to known Tripodegelenken. The distance between a profile of the gothic trained Wälzkörperlaufbahn to the opposite track is reduced to the center of the profile, whereby a centering effect for the Wälzkörperkäfig can be achieved. This effect can be enhanced by the use of larger external rolling elements, in particular outer spheres. That is, by using enlarged outer rolling elements, in particular outer balls, a centering force can be generated for the Wälzkörperkäfig and improved pressure distribution over the length of the rolling body track can be achieved. Such a configuration of the rolling element raceways or opposing raceways is easy and inexpensive to manufacture.

Particularly preferred is a tripod joint, in which the at least one rolling body track has a shape symmetrical with respect to its longitudinal extension. This ensures that over the entire length of the rolling body track a uniform pressure distribution can be generated. This further ensures that the rolling elements increase in size from the center of the rolling body raceway to the ends of the rolling body raceway. The outermost rolling elements are advantageously the same size, to the middle of the rolling body, the size of the rolling elements decreases. If, for example, five rolling elements are provided on a rolling body raceway, the average rolling body is preferably the smallest in its dimensions compared to the other rolling bodies. Towards the outside, that is to the ends of the rolling body raceway, the rolling elements increase in size.

According to a further preferred development of the invention can therefore be provided in the tripod joint, that at least three rolling elements are provided for the at least one rolling element, which are designed in particular spherical or cylindrical, and that the radii of at least three rolling elements of at least one central rolling elements to increase the outer rolling elements. Preferably, four or five rolling bodies are assigned to a rolling body raceway. However, it is also conceivable that a rolling body raceway and the corresponding opposite straight track of the outer joint part are associated with six or more rolling elements. Due to the special design of the rolling body of a rolling element can be ensured that each rolling element is always centered on the Wälzkörperlaufbahn, while the rolling elements run along the corresponding raceway of the outer joint part. The exact centering of the rolling elements between the rolling body raceway and the raceway of the outer joint part is ensured in particular by the Wälzkörperkäfig.

It is possible that the Wälzkörperlaufbahnen all rolling elements of a tripod joint are designed differently. However, particularly preferred is a tripod joint, in which all Wälzkörperlaufbahnen all rolling elements of the Tripodegelenkes are the same. Particularly preferred is a tripod joint, in which each rolling element track is designed as a Gothic track and the rolling elements between the gothic Wälzkörperlaufbahnen and the corresponding opposite straight Gothic tracks of the outer joint part of the tripod joint are formed as balls of different sizes. Such trained Tripodegelenk has a very low wear and a long life associated with it. Furthermore, such a Tripodegelenk is very durable and extremely robust.

Further advantages, features and details of the invention will become apparent from the following description in which, with reference to the drawings, embodiments of the invention are described in detail. The features mentioned in the claims and in the description may each be essential to the invention individually or in any desired combination.

They show schematically:

1 FIG. 2: a side view of a housing part of a housing of a rolling element with a rolling body raceway according to the prior art, FIG.

2 FIG. 2: a side view of a housing part of a housing of a rolling element of a tripod joint, which is designed in accordance with the construction principle according to the invention, FIG.

3 a side view of another housing part of a housing of a rolling element of a tripod joint, which is designed according to the inventive design principle, and

4 a side view of rolling elements, which are arranged between a straight track of the outer joint part of a tripod joint according to the invention and a housing part of a housing of a rolling element of an inner joint part of the tripod joint according to the invention.

Elements with the same function and mode of action are in the 1 to 4 each provided with the same reference numerals.

1 schematically shows a side view of a housing part of a housing 1 a rolling element of an inner joint part of a Tripodegelenkes, according to the prior art. The housing 1 or housing part of the housing 1 has a straight Wälzkörperlaufbahn 3 on. Parallel to this straight rolling body raceway 3 of the inner joint part, a raceway of the outer joint part of the tripod joint is arranged, wherein the raceway of the outer joint part in the 1 not shown. The at the Wälzkörperlaufbahn 3 adjacent rolling elements are the same size in such a known tripod joint, which has the disadvantage that the largest wear on the central rolling elements. In such a straight Wälzkörperlaufbahn the Wälzkörperkäfig that holds the rolling elements can be pushed by micro-pulses from its theoretical zero position.

In the 2 is a schematic side view of a housing 1 or a housing part of a housing 1 a rolling element of an inner joint part of a Tripodegelenkes shown, which is formed according to the inventive design principle. The housing 1 has a rolling body raceway 3 on, in the running direction 5 the rolling element, not shown, is designed such that the distance of the rolling body raceway 3 to an opposite straight track of the outer joint part of the Tripodegelenkes not over the entire Wälzkörperlaufbahn 4 is constant and to both ends of the rolling element raceway 3 increases. In this embodiment, the rolling body raceway 3 of the housing 1 a rolling element of the tripod joint is the Wälzkörperlaufbahn 3 arcuate, in particular circular segment-shaped. Due to this special design of the rolling element raceway 3 and an opposite straight track of an outer joint part of the tripod joint is ensured that the rolling elements, which are formed in particular as balls, from the center of the rolling body raceway 3 grow larger towards the outside. The rolling elements, which are held by a Wälzkörperkäfig center due to their different size and the special shape of the rolling body track 3 the Wälzkörperkäfig on the housing 1 the inner joint part of the tripod joint. The housing 1 the rolling element of the tripod joint has a receiving opening 2 for supporting a journal of the tripod joint. The rolling element raceway 3 is designed over a radius R4 so that the highest point is in the Wälzkörperlaufbahnmitte. The rolling element raceway 3 of the housing 1 , which is designed here as a half-shell, and the raceway of the outer joint part do not run parallel to each other. The radius R4 of the rolling body track 3 is greater than the radius R3 of the receiving opening 2 for supporting a journal of the tripod joint. Such a configuration of the rolling body raceway 3 or the housing part of the housing 1 The Tripodegelenkes is easy and inexpensive to implement. At the ends 8th the rolling element raceway 3 are inlet areas 9 provided in the form of rounding or bevels.

The 3 represents a variant of a housing 1 with corresponding rolling body career 3 a rolling element of a Tripodegelenkes. In this embodiment of the tripod joint, the rolling body track 3 a middle section b which is rectilinear and parallel to a corresponding, opposite straight track of an outer joint part of the tripod joint. That is, in this central portion b of the rolling body raceway, a straight portion is provided, wherein the distance of the rolling body raceway 3 is constant from the corresponding, opposite straight track of the outer joint part of the Tripodegelenkes. The distance between the rolling element raceway 3 to the opposite straight track of the outer joint part decreases from the transition of the middle section b to the ends 8th the rolling element raceway 3 to. That is, in the outer portions a, c of the rolling element raceway 3 takes the distance between the Wälzkörperlaufbahn 3 and the opposite straight track of the outer joint part to the ends 8th the rolling element raceway 3 to. At the ends 8th the rolling element raceway are inlet areas 9 provided in the form of rounding or chamfering. In the middle section b of the rolling element raceway 3 a rolling element, but preferably a plurality of rolling elements, may be provided. Also at the respective outer sections a, c one or more rolling elements can be provided in each case. Both the rolling element raceway 3 according to the 2 as well as the 3 are symmetrical. In this way it can be ensured that over the on the corresponding Wälzkörperlaufbahnen 3 along rolling elements, the Wälzkörperkäfige that hold the rolling elements are centered.

In the 4 is a schematic side view of a housing 1 or a holding shell of a housing 1 a rolling element of a Tripodegelenkes shown, which is formed according to the inventive design principle. Furthermore, the 4 a corresponding, opposite straight career 6 an outer joint part 10 to take a tripod joint. Between the straight track 6 of the outer joint part 10 the tripod joint and the rolling element raceway 3 of the housing 1 the rolling element of the inner joint part of the tripod joint are different sized Wälzköper 4a . 4b arranged. The rolling elements 4a . 4b are held by a Wälzkörperkäfig not shown. The middle rolling elements 4a have a smaller diameter R1 than the outer rolling elements 4b on. That is, the diameter R2 of the outer rolling elements 4b is significantly larger than the diameter R1 of the middle rolling elements in this embodiment of the tripod joint according to the invention 4a , By using the larger outer rolling elements 4b , which are formed in particular as balls, a centering force can be generated on the roller body cage, not shown, and an improved pressure distribution over the rolling body raceway 3 or the career path 6 of the outer joint part can be achieved.

LIST OF REFERENCE NUMBERS

1

Housing of an inner joint part of a tripod joint

2

receiving opening

3

Wälzkörperlaufbahn the inner joint part

4a

middle rolling element

4b

outer rolling element

5

Running direction of the rolling elements

6

Raceway of the outer joint part

7

distance

8th

Ends of the rolling body raceway

9

intake area

10

Joint outer part of a tripod joint

R1

Radius of medium rolling elements

R2

Radius of outer rolling elements

R3

Radius receiving opening

R4

Radius rolling element raceway

a

outer portion of the rolling element raceway

b

middle section of the rolling element track

c

outer portion of the rolling element raceway

Claims (8)

Tripod joint, comprising an inner joint part and an outer joint part, wherein the inner joint part comprises a tripod star with pins and the tripod esters associated rolling elements, wherein the rolling elements each have a housing ( 1 ) and a receiving opening formed therein ( 2 ) for supporting a journal and at least one rolling body raceway ( 3 ), as well as each rolling element raceway ( 3 ) of the housing ( 1 ) associated rolling elements ( 4a . 4b ) for supporting on corresponding, the rolling element raceways ( 3 ) of the housing ( 1 ), opposite straight tracks ( 6 ) of the outer joint part of the tripod joint, characterized in that at least one of the Wälzkörperlaufbahnen ( 3 ) in the running direction ( 5 ) of the rolling elements ( 4a . 4b ) is designed such that the distance ( 7 ) of the at least one rolling body raceway ( 3 ) from the corresponding, opposite straight track ( 6 ) of the outer joint part not over the entire Wälzkörperlaufbahn ( 3 ) is constant and at both ends of the at least one rolling element ( 3 ) increases. Tripod joint according to claim 1, characterized in that the distance ( 7 ) of the at least one rolling body raceway ( 3 ) from the corresponding, opposite straight track ( 6 ) of the outer joint part to both ends of the at least one Wälzkörperlaufbahn ( 3 ) by a respective convexly curved, a circular segment-shaped or a linear course of the at least one Wälzkörperlaufbahn ( 3 ) increases. Tripod joint according to one of claims 1 or 2, characterized in that in a central portion (b) of the at least one rolling body track ( 3 ) a straight area is provided, in which the distance ( 7 ) of the at least one rolling body raceway ( 3 ) from the corresponding, opposite straight track ( 6 ) of the outer joint part is constant. Tripod joint according to one of claims 1 to 3, characterized in that at the ends ( 8th ) of the at least one rolling body raceway ( 3 ) Inlet areas ( 9 ) are provided in the form of rounding, bevels or chamfers. Tripod joint according to one of claims 1 to 4, characterized in that the at least one Wälzkörperlaufbahn ( 3 ) and / or the at least one Wälzkörperlaufbahn corresponding, opposite straight track ( 6 ) of the outer joint part has / have a Gothic track shape. Tripod joint according to one of claims 1 to 5, characterized in that the at least one Rolling element track ( 3 ) one with respect to its longitudinal extent ( 9 ) has symmetrical shape. Tripod joint according to one of claims 1 to 6, characterized in that for the at least one Wälzkörperlaufbahn ( 3 ) at least three rolling elements ( 4a . 4b ) are provided, which are designed in particular spherical or cylindrical, and that the radii (R1, R2) of the at least three rolling elements ( 4a . 4b ) of at least one middle rolling element ( 4a ) to the outer rolling elements ( 4b ) increase. Tripod joint according to one of claims 1 to 7, characterized in that all Wälzkörperlaufbahnen ( 3 ) of all rolling elements of the tripod joint ( 1 ) are the same.

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