Tripod gimbals and methods for manufacturing tripod gimbals

Abstract

A tripod joint (1) comprising a joint outer part (20) with a pair of tracks (21), a tripod star structure (10) with radially protruding pins (12) and rolling elements (13) rotatably supported on the pins (12) of the tripod star structure (10) around the longitudinal axis (Z) of the respective pin (12). Each rolling element (13) comprises an outer ring (14) with an outer circumference (14a) for rolling along the pair of tracks (21) of the joint outer part (20), an inner ring (15) in contact with one pin (12) of the tripod star structure (10) by its inner circumference (15a) and a needle (16) arranged around the pin (12, 12') in an annular space (17) between the outer circumference (15b) of the inner ring (15) and the inner circumference (14b) of the outer ring (14). In the direction of rotation (D) of the tripod star structure (10) relative to the associated pin (12), the inner circumference (15a) of the inner ring (15) of the rolling element (13) has a head gap (KS) towards the surface of the pin (12) which decreases towards two contact positions (K1, K2) on the pin (12) on both sides of the direction of rotation (D). The invention furthermore relates to a method for manufacturing such a tripod joint.

Description

TECHNICAL FIELD

[0001] The invention relates to a tripod joint comprising a joint outer part with a pair of tracks, a tripod star structure with radially protruding pins and rolling elements rotatably supported on the pins of the tripod star structure around a longitudinal axis of the respective pin, wherein each rolling element comprises an outer ring with an outer circumference for rolling along the pair of tracks of the joint outer part, an inner ring contacting one pin of the tripod star structure by an inner circumference thereof and a needle arranged around the pin in an annular space between the outer circumference of the inner ring and the inner circumference of the outer ring. BACKGROUND

[0002] Synchronizing joints are used in half shafts of motor vehicles in order to transmit the drive torque of a vehicle drive to a vehicle wheel. Here, not only the angle change between the vehicle wheel and the vehicle drive has to be compensated, but also length changes. In synchronizing joint shafts which are used as half shafts in motor vehicles, the synchronizing joint on the wheel side is therefore usually designed as a fixed connection, while the synchronizing joint on the drive side usually has the possibility of axial displacement. The maximum deflection angle of the synchronizing joint on the wheel side is in the order of magnitude of approximately 45 to 50 degrees, while the maximum deflection angle of the synchronizing joint on the vehicle drive side is significantly smaller at approximately 24 degrees. Synchronizing joints suitable for the vehicle drive side can be designed, for example, as ball-type movable joints or tripod joints.

[0003] The invention relates to such a tripod joint, which has a better efficiency compared to VL ball-type movable joints.

[0004] Tripod joints of the type mentioned above are known, for example, from DE 10 2016 222 521 A1 and DE 10 2009 013 038 A1.

[0005] With the increasing popularity of electric vehicles, the overall load on the half shafts is more critical. The rolling elements are involved in particular in pitting and stress of the needles in these tripod joints.

[0006] A remedy is the use of larger tripod joints, but this increases the required space and weight. In addition, the larger size is also disproportionately expensive due to the small production quantities.

[0007] Alternatively, the already mentioned VL ball-type movable joints can also be used. However, the cost is the sacrifice of efficiency and accordingly means an increase in energy consumption, which is particularly problematic in electric cars due to the limited battery capacity.

[0008] From DE 102020 102 218 A1 a tripod joint is known in which the needles roll directly on the surface of the pins of the tripod star structure without intermediate connecting rolling elements, that is to say in direct contact with them. In order to increase the service life or in order to enable operation at higher loads it is suggested there, without increasing the diameter of the pins, to distribute the load more uniformly on the needles in contact with the pins. To this end the shape of the needles should be changed from the hitherto customary cylindrical or round shape to, for example, an oval shape, taking into account the cross section of the needles. In the joint to be improved here, however, the needles do not roll on the outer circumference of the pins, but on the inner part of the rolling elements, which themselves are rotatably supported on the pins. SUMMARY

[0009] Against this background, the technical problem addressed by the present application is to adapt a tripod joint of the type described above to higher overall loads.

[0010] The tripod joint according to the application comprises a joint outer part with a pair of tracks, a tripod star structure with radially protruding pins and rolling elements rotatably supported on the pins of the tripod star structure around the longitudinal axis of the respective pin, wherein each rolling element comprises an outer ring with an outer circumference for rolling along the pair of tracks of the joint outer part, an inner ring which is in contact with one pin of the tripod star structure by its inner circumference and a needle which is arranged around the pin in an annular space between the outer circumference of the inner ring and the inner circumference of the outer ring. It is characterized in that the inner circumference of the inner ring of the rolling element has a head clearance towards the surface of the pin in the direction of rotation of the tripod star structure relative to the relevant pin, which head clearance decreases towards two contact positions on the pin on both sides of the direction of rotation.

[0011] By the inner ring supported in this way a better force distribution is achieved in the joint, which manifests itself in an increased service life and / or an increased load capacity.

[0012] The load acting in the direction of rotation of the tripod star structure is thus distributed over two regions on both sides of the actual direction of rotation, whereby the stress of the assembly of the rolling elements is reduced. The maximum Hertz pressure in the tripod joint is reduced.

[0013] Preferably, the contact angle at the contact positions is in the range from 5° to 35°. The contact angle of the contact positions on the pin in a plane perpendicular to the longitudinal axis of the pin is defined here as the angle between a straight line through the contact position and a point of passage of the longitudinal axis of the pin through said plane and a straight line through the longitudinal axis of the pin as a point of passage of said plane in the direction of rotation of the tripod star structure. It has been shown experimentally that a particularly good force distribution can be achieved in the tripod joint thereby.

[0014] The contact angles of the two contact positions can differ in magnitude here. However, it is preferred that the contact angles are of the same magnitude for both contact positions on both sides of the direction of rotation.

[0015] The contact positions are ideal points in a cross-section perpendicular to the longitudinal axis of the pin, but in reality extend over an arc-shaped section of the surface of the pin in a direction around the longitudinal axis of the pin. For geometrical reasons, the center of this arc-shaped section can be regarded as the relevant contact point.

[0016] In a preferred embodiment, the head clearance KS of the inner ring of the rolling element and the outer circumference of the pin at its position towards the direction of rotation is determined in the following way:

[0017] Ks = KSF * a / 1000

[0018] wherein KS is a value in millimeters, a is the existing maximum contact angle in degrees of the two contact positions, and KSF is a value between 1 and 8.

[0019] According to a further special embodiment of the application, the surface of the pin is in a cross-section on its side towards the direction of rotation between the two contact positions flattened (or called planarized) to provide the head clearance. This flattening can be obtained very simply in production technology, for example, by post-machining of the pins of the tri-star structure. In the simplest case, the flattening can be a flat surface on the surface of the pin.

[0020] According to a further special embodiment, the surface of the pin has in a cross-section between the two contact positions a curved section, the radius of which is greater than the distance of the contact positions from the longitudinal axis of the pin. In comparison to a planar surface, less material needs to be removed here. Furthermore, the soft transition into the curved section has a positive effect on the bearing of the inner ring on the pin.

[0021] In a variant, the curved section tangentially transitions into two generating circles for the contact positions, which respectively tangentially contact a base circle at the relevant contact position, wherein the radius of the generating circles is smaller than the radius of the curved section by an amount. This achieves the simple production of the desired head clearance.

[0022] The curved section is preferably convex, i.e. curved outwards, whereby particularly low maximum Hertz pressures in the tri-star joint are formed. However, a concave design is also possible. Although this reduces the load on the pin, it leads to higher Hertz pressures compared to the convex design.

[0023] According to a further special embodiment of the application, the outer circumference of the inner ring is designed cylindrical in the region of the contact with the pin. Thereby, a uniform force distribution on the pin starting from the two contact positions is facilitated, whereby the maximum load on the pin is greatly reduced.

[0024] According to a further special embodiment of the application, the surface of the pin is designed to be spherical or convexly curved in a longitudinal section plane which contains the longitudinal axis of the respective pin. This achieves that the axis of rotation of the rolling element pivots relative to the longitudinal axis of the associated pin, i.e. the axis of rotation of the spider structure forms an angle relative to the axis of rotation of the outer part of the gimbal, when the gimbal is bent.

[0025] The above-mentioned problems are furthermore solved by a method for producing a tripod gimbal, wherein the spider structure is produced by means of a forming technique. The method is characterized in that the forming-technological production of the spider structure is realized by means of a split mold, the split plane of which forms an angle with the longitudinal axis of the respective pin and the axis of rotation of the spider structure in the region of the pins of the spider structure, wherein the pins are provided with a cross section which is non-circular in a section plane perpendicular to the longitudinal axis of the pin when produced by means of the forming technique, which cross section forms a flattening in the direction of rotation of the spider structure.

[0026] The contour of the pin can here be formed at least in the head gap region, but preferably overall, in a forming technique, the production expenditure thereby remaining particularly low.

[0027] The contour of the pin, especially in the head gap region, can however also be subjected to a calibration post-processing if necessary. This calibration post-processing can in principle be a material-removing hard machining. It is however preferred to calibrate the contact region by means of a forming technique, thereby forming the final head gap. In this case the expensive material-removing hard machining can be completely dispensed with. Furthermore, a higher process safety is achieved in the calibration by means of a forming technique compared to a material-removing calibration hard machining, since a possible contour deviation between the blank and the finished piece can practically be ruled out in the forming compared to the hard machining.

[0028] The above-mentioned problems are furthermore solved by a method for producing a tripod gimbal, wherein the spider structure is produced by means of a forming technique, wherein the forming-technological production of the spider structure is realized by means of a split mold and the axis of rotation (A) of the spider structure is perpendicular to the split plane of the mold. In this case the contour of the pin is produced at least in the head gap region by means of a material-removing post-processing. BRIEF DESCRIPTION OF DRAWINGS

[0029] The application is further explained below on the basis of the embodiments shown in the drawings. In the drawings:

[0030] Figure 1 A sectional view of an embodiment of a tripod gimbal according to the application is shown, which is stretched,

[0031] Figure 2 A sectional view through a pin and a rolling element perpendicular to the longitudinal axis of the pin, which coincides with the axis of rotation of the rolling element in the unstretched position,

[0032] Figure 3 Longitudinal sectional view through the rolling element, with the sectional plane coinciding with the axis of rotation of the rolling element,

[0033] Figure 4 Spatial view showing the tripod star structure,

[0034] Figure 5 Schematic view similar to Figure 2

[0035] Figure 6

[0036] Figure 7

[0037] Figure 8

[0038] Figure 9

[0039] Figure 10 DETAILED DESCRIPTION

[0040] Figure 1

[0041] The tripod joint 1 comprises an inner joint part 10 in the form of a tripod star structure 10 having an axis of rotation A and an outer joint part 20 having an axis of rotation B. On the outer joint part a raceway pair 21 is configured in which the inner joint part is guided axially, i.e. in the direction of the axis of rotation B. When the tripod joint is stretched, the axes of rotation A and B are aligned with each other. If, in contrast, the tripod joint 1 is bent, a bending angle ≠ 0° is enclosed between them.

[0042] The tripod star structure 10 has a central shaft section 11 and a plurality of, preferably three, pins 12 projecting from the shaft section 11. The central shaft section 11 can be designed as a ring body.

[0043] ​​​​​​​The pins 12 are arranged at equal distances relative to each other in the circumferential direction around the rotation axis A of the gimbaling inner part or spider structure 10. Their longitudinal axes Z extend substantially radially relative to the rotation axis A and are preferably located in a common plane, as in the shown embodiment.

[0044] Furthermore, the spider gimbal 1 comprises on the spider structure 10 for each pin 12 a rolling element 13 which is rotatably supported on the associated pin 12 of the spider structure 10 around the longitudinal axis Z of the pin 12.

[0045] The pins 12 have respectively a profiled surface 12a for supporting the rolling element 13, which will be explained in detail below.

[0046] Each rolling element 13 comprises an outer ring 14 and an inner ring 15 and arranged therebetween rolling bodies 16, so that the outer ring 14 and the inner ring 15 can be twisted relative to each other.

[0047] The outer ring 14 and the inner ring 15 are preferably designed as rotationally symmetrical components.

[0048] In particular, each rolling element 13 can be rolled by an outer peripheral portion 14a of the outer ring 14 along the raceways 21a, 21b of the gimbal outer part 20. The profile of the outer peripheral portion 14a can for this purpose be outwardly convexly curved in cross section. The raceways 21a and 21b can accordingly have a concave cross-sectional profile, which is visible in Figure 1 .

[0049] The inner ring 15 is in contact with the associated pin 12 of the spider structure 10 by its inner peripheral portion 15a.

[0050] The rolling bodies are designed here as needles 16 (or also as rollers), which are arranged around the pin 12 in an annular space 17 between an outer peripheral portion 15b of the inner ring 15 and an inner peripheral portion 14b of the outer ring 14 and are in line contact with the outer peripheral portion 15b of the inner ring 15 and the inner peripheral portion 14b of the outer ring 14, respectively.

[0051] The inner peripheral portion 15a of the inner ring 15 can be designed here as cylindrical.

[0052] In the context of the present disclosure, inner and outer peripheral portions are understood as the associated surfaces and not as dimensions.

[0053] In contrast, the surface 12a of the pin 12 can be designed as convexly spherical in a longitudinal section plane which contains the longitudinal axis Z of the respective pin 12.

[0054] Due to the convex design of the surface 12a of the pin 12 which the inner peripheral portion 15a of the inner ring 15 is in contact with, the inner ring 15 can be tilted relative to the longitudinal axis Z of the associated pin 12 when the spider gimbal 1 is bent. It can also be moved axially in the direction of the longitudinal axis Z of the pin 12.

[0055] The ability to rotate, tilt, and move axially around pin 12 can also be achieved in other ways. Figure 1 The design of the multi-directionally rotatable support shown to enable rocking motion represents only one possibility for the rolling element 13 to illustrate this function.

[0056] The outer universal joint component 20 of the tripod universal joint 1 has its own engagement section for each rolling element 13.

[0057] The occlusal segment is, for example, designed in a sleeve shape and can have a constant cross-sectional profile along its axial length.

[0058] exist Figure 1 In the illustrated embodiment, the engagement section has a pair of raceways 21 extending parallel to the rotation axis B of the universal joint outer component 20 on its inner circumference. The raceway pair has raceways 21a and 21b that are circumferentially opposite each other. These raceways 21a and 21b engage with the outer circumference 14a of the corresponding rolling element 13, wherein, depending on the direction of rotation and operating conditions, one raceway 21a is loaded and the load on the opposite raceway 21b is released. The raceways 21a and 21b on the universal joint outer component 20 extend parallel to the rotation axis B of the universal joint outer component 20, respectively.

[0059] By shaping the raceways 21a and 21b on the outer component 20 of the universal joint and the outer periphery 14a of the outer ring 14 of the rolling element 13, the rolling element 13 moves back and forth parallel to the axis of rotation B of the outer component 20 when the universal joint 1 rotates with the component shafts A and B bent relative to each other. The rotational degree of freedom required for this can be provided, for example, between the pin 12 and the inner ring 15 of the rolling element 13, as described above.

[0060] Especially from Figure 4 and Figure 5 It can be seen that in the inner circumference 15a of the inner ring 15 of the rolling element 13 and in the tripod structure 10 Figure 5 A so-called head gap KS is provided between the surfaces 12a of the pin 12 supporting it in the rotation direction represented by D. The head gap decreases on both sides towards the two contact positions K1 and K2 outside the rotation direction D of the tripod structure 10.

[0061] In a cross-section perpendicular to the longitudinal axis Z of the corresponding pin 12, this contact on both sides of the rotation direction D increases the service life of the rolling element 13 by balancing the force distribution in the tripod universal joint 1. This does not preclude other contact locations.

[0062] In principle, the two contact positions K1 and K2 on the left and right sides of the rotation direction D can extend on the surface 12a of the inner circumference 15a of the pin 12 facing the inner ring 15 in the longitudinal direction Z of the pin 12, such as...Figure 4 are exemplarily shown in

[0063] This extension can however also be interrupted in the Z direction if necessary, so that for each contact location K1 and K2 two or more contact islands K1a, K1b and K2a, K2b are formed in the Z direction, which are spaced apart from one another, as is exemplarily shown in Figure 10 Thereby the introduction of forces can be further improved, especially in terms of the range of the important operating bending angles. On the other side of the contact locations K1 and K2 or the contact islands K1a, K1b and K2a and K2b there can also be regions with larger gaps in the circumferential direction around the longitudinal axis Z of the pin 12.

[0064] Thus, as is shown in Figure 9 a primary contact area HK is formed around each contact location K1 and K2, and a secondary contact area NK is formed between the two primary contact areas HK in the direction of rotation D. In the primary contact areas HK a clear increase in force transmission occurs compared to a circular cross-sectional profile. In the secondary contact areas NK the force transmission is clearly reduced, which leads to a load equalization of the rolling body, here the needle 16, and to a clear reduction of load peaks thereof.

[0065] Figure 4 The contact angles a1 and a2 for the two contact locations K1 and K2 are also shown in. Preferably, the two contact angles a1 and a2 lie in the range of 5° to 35°. The contact angle a1 or a2 of the contact location K1 or K2 on the pin 12 in a plane perpendicular to the longitudinal axis Z of the pin 12 is here the angle between a straight line through the contact location and the longitudinal axis Z through a point P of the plane and a straight line through the longitudinal axis Z through the point P of the plane in the direction of rotation D of the three-prong star structure 10.

[0066] In the shown design angle, the contact angles a1 and a2 for the two contact locations K1 and K2 are identical in magnitude. However, a design is also possible in which the contact angles a1 and a2 differ from one another.

[0067] The head gap KS is preferably determined from the maximum existing contact angles a1 and a2 of the two contact locations K1 and K2 as follows:

[0068] Ks = KSF * a / 1000

[0069] Here, KS is a value in millimeters, in which a is the maximum existing contact angle a1 and a2 of the two contact locations K1 and K2 in degrees, and furthermore KSF is a value of 1 to 8.

[0070] The contact gap KS can be adjusted in such a way that when the inner ring 15 has a cylindrical inner periphery 15a, the surface 12a of the pin 12 is beveled in cross section on its side facing in the direction of rotation D between the two contact locations K1 and K2.

[0071] This flattening 18 can be obtained, for example, by material removal of the pin 12 in the region between the contact points K1 and K2, as Figure 4 is shown.

[0072] The flattening 18 can be designed, for example, as a flat surface or line in the cross-sectional plane. However, since this involves a relatively high material removal, it is advisable to shape the profile between this flat surface or line and a circular arc having a constant radius about the longitudinal axis Z.

[0073] As Figure 6 and Figure 7 shown, without being limited thereto, the surface 12a of the pin 12 can be formed at least section-wise in the cross section between the two contact points K1 and K2 by a curved section H, the radius R3 of which is greater than the distance of the contact points K1 and K2 from the longitudinal axis Z of the pin 12.

[0074] This curved section H can be generated, for example, very simply by means of a base circle K and two generating circles E1 and E2 having radii R1 and R2.

[0075] The generating circles E1 and E2 tangentially contact the base circle K at the contact points K1 and K2.

[0076] The intersection of the angular lines of the contact points K1 and K2 is marked as S in Figure 6 . The intersection S can coincide with the center of the base circle K. If the contact angles a1 and a2 are equal, the intersection S lies on the rotational direction line D. However, it can also be displaced relative to the center of the base circle K on the rotational direction line D. If the contact angles a1 and a2 are different, the intersection S is laterally displaced relative to the rotational direction line D.

[0077] The curved section H can be designed, in particular, such that it tangentially transitions into the two generating circles E1, E2 for the contact points K1, K2.

[0078] In particular, the radii R1 and R2 of the generating circles E1 and E2 are smaller than the radius R3 of the curved section H by an amount.

[0079] The cross-sectional progression of the surface 12a of the pin 12, which continues up to the contact points K1 and K2, can be guided, if necessary, from the profile of the curved section H by the profiles of the generating circles E1 and E2, as Figure 6 is shown.

[0080] On the other side of the flattened region between the contact points K1 and K2, the cross-sectional progression of the surface 12a of the pin 12 can be circular, for example.

[0081] This implementation firstly produces the pin 12 by means of a shaping technique, optionally followed by a calibration post-processing, preferably only between the contact locations Kl and K2. This is much less costly than, for example, free-form milling of the entire surface 12a of the pin 12.

[0082] The pin 12 is preferably produced by means of a shaping technique by means of a die, the die parting plane W of which extends along the longitudinal axis Z and is at a 90° angle to the direction of rotation D, as shown in Figure 8 . Thereby a shaving 18 can be produced with very little outlay, so that no or in any case only little post-processing is required in the region of the shaving.

[0083] Alternatively, the production of the pin 12 by means of a shaping technique can also firstly be carried out by means of an excess, followed by a hard machining of the pin surface 12a. In this case the die parting plane can be provided at a 90° angle to the direction of rotation D or in the direction of rotation D, i.e. perpendicular to the rotation axis A of the spider structure 10, as shown in Figure 8 .

[0084] The curved section H can be convex, i.e. curved outwards, as shown in Figure 6 . This results in very small maximum Hertz pressures in the joint 1 and a low load on the needle 16.

[0085] However, it is also possible in principle to provide the curved section H with a negative radius R3, thereby forming a concave curvature of the curved section H, as shown by way of example in Figure 7 . The load on the needle 16 is reduced here, but the maximum Hertz pressure is higher compared to the variant according to Figure 6 .

[0086] Furthermore, in a variant of the above-described embodiment, the head gap KS can be provided not only in the direction of load, i.e. in the main direction of rotation D of the spider joint 1, but also in the opposite direction of rotation. This is particularly recommended if the vehicle does not travel in the main direction of travel, but to a non-negligible extent in the opposite direction. Furthermore, it is not necessary to distinguish between left and right joint axes on the vehicle. This means that in the embodiment shown, for each direction of rotation, i.e. the direction D and its opposite, a shaving 18 is provided between the two contact locations or contact island groups by means of the respective head gap.

[0087] The present application achieves a spider joint 1 with a rolling element 13 as a structural unit, which can withstand a high overall load, i.e. can be operated at high loads and / or has a long service life without an increase in the outer dimensions.

[0088] Finally, a plurality of advantageous methods for producing, in particular, the spider structure 10 are described.

[0089] In the first manufacturing method, the three-star structure 10, including its pins 12, is manufactured by a forming technique. The surface 12a of the pins 12 is obtained here by forming through a mold, rather than, for example, by turning, which is usually used for this purpose. Thus, when manufactured by a forming technique, the pins 12 are provided with a cross section that is non-circular in a cross section perpendicular to the longitudinal axis Z of the pins 12, which forms a flat 18 in the direction of rotation D.

[0090] A separate mold is used here, which, unlike in the conventional manufacturing process, has a mold parting plane W that is defined in the region of the pins 12 by the longitudinal axis Z of the respective pin 12 and the axis of rotation A of the three-star structure 10. The mold parting plane W thus extends at a 90° angle to the direction of rotation D. As a result, the separation line on the pins 12 is located within one of the contact regions NK and HK.

[0091] The contour of the surface 12a and the pin 12 is thus ultimately formed in the forming technique, at least in the region of the head gap KS, but preferably overall, with manufacturing outlay remaining particularly low.

[0092] The calibration in the forming technique is preferably carried out as cold forming. If necessary, the hitherto required blasting of the formed three-star structure blank, for example for removing scale, can be omitted.

[0093] In order to reduce the forming forces in the calibration in the forming technique, it is possible to select the residual amount of the three-star structure blank 10 in the secondary contact region NK to be smaller than in the primary contact region HK.

[0094] This constitutes a different advantage compared to turning or milling of the surface 12a. There are more design possibilities, for example, in the final contour manufactured by the forming technique. In particular, the contact locations with the plurality of contact islands K1a, K1b, K2a, K2b can be manufactured more easily, for example.

[0095] The transitions in relation to the maximum component stresses in the pins 12 can be designed more softly.

[0096] Furthermore, the coordination between the head gap KS and the contact locations can be more precise and reliable.

[0097] The surface 12a of the pins 12 is usually hardened. The depth of the hardening can be reduced by the method according to the application, since there is no edge layer through additional machining. This simplifies the hardening process, in particular, for example, shortens the time.

[0098] Furthermore, no contour misalignment between the blank and the finished part can occur when forming, resulting in a higher process safety.

[0099] The final calibration can be done in two ways.

[0100] In the first case, only the main contact area HK, but not the secondary contact area NK and the section of the surface 12a lying outside the main contact area HK, is treated by means of the forming technique, so that here it is referred to as a partial calibration of the surface 12a of the pin 12. The advantage of this method is the comparatively low forming forces.

[0101] In the second case, the calibration by means of the forming technique is carried out by means of a die at the main contact area HK and the secondary contact area NK, whereby a higher profile accuracy is achieved than in the first case, so that here it can be said to be a precision calibration.

[0102] In this calibration by means of the forming technique, in the first case and in the second case, a small amount of material of the pin 12 is pressed into the area outside the main contact area HK. For this purpose, some air (insufficient dimensioning) is left in the blank when it is manufactured as a compensation for the calibration.

[0103] At the calibration, a defined functional surface structure can additionally be transferred from the tool onto the surface 12a of the pin. It can differ from its environment, for example, by a higher or lower surface roughness or other surface refinement, for example, in order to influence the lubricant supply.

[0104] In the second manufacturing method, a blank for a tripod structure 10 including its pins 12 is first manufactured by means of the forming technique. The die parting plane W extends transversely to the direction of rotation D, as in the first manufacturing method, i.e. as shown in Fig. 1. The separating burr (German Trenngrate) is thus again in a functionally non-critical area away from the direction of rotation D. Figure 10

[0105] The pins 12 are at least partially first machined with a surplus on their rolling-related surfaces 12a with respect to the rolling elements 13. The flattening of the main contact area HK and, if necessary, even the formation of the elevations can thus already be carried out on the blank.

[0106] The blank is, after hardening, subjected to a cutting-type hard machining for the calibration of at least the main contact area HK, so that the final profile is finally obtained. By the pre-shaping of the blank, the machining effort remains low and the necessary hardening depth is moderate.

[0107] In the third manufacturing method, a blank for a tripod structure 10 is manufactured with a die in the conventional manner, the die parting plane of which coincides with the direction of rotation D. The manufacture of the pins 12 is carried out here in oversize. After hardening, a material-removing hard machining is carried out to produce the final profile of the surface 12a, forming the above-mentioned main and secondary contact areas HK and NK. Alternatively, it is possible here to manufacture a blank which already has the flattening of the pins 12.

[0108] ​The application has been explained in detail above on the basis of different embodiments and variants. This was only for the purpose of proving the feasibility of the application. Individual technical features explained above in the context of further individual features can also be realized independently of these features and in combination with further individual features, even if this is not explicitly stated, as long as this is technically feasible. The application is therefore explicitly not limited to the specifically illustrated embodiments and implementation variants and variants, but comprises all design solutions defined by the claims.

[0109] List of reference signs:

[0110] 1 tripod 14b inner periphery of outer ring

[0111] 10 tripod star structure 15 inner ring

[0112] 11 shaft section 15a inner periphery of inner ring

[0113] 12 pin 15b outer periphery of inner ring

[0114] 13 rolling element 16 needle (rolling body)

[0115] 14 outer ring 17 annular space

[0116] 14a outer periphery of outer ring 18 chamfer

[0117] A rotational axis of the tripod star structure

[0118] B rotational axis of the gimbal outer part

[0119] D rotational direction of the tripod star structure

[0120] E1 generating circle of the first contact position

[0121] E2 generating circle of the second contact position

[0122] H curved section

[0123] HK main contact area

[0124] K base circle

[0125] K1 first contact position

[0126] K1a contact island

[0127] K1b contact island

[0128] K2 second contact position

[0129] K2a contact island

[0130] K2b contact island

[0131] KS head gap

[0132] NK next contact area

[0133] P point of passage

[0134] R1 radius of the generating circle of the first contact position

[0135] R1 radius of the generating circle of the second contact position

[0136] R3 radius of the curved section

[0137] W mold parting plane

[0138] Z longitudinal axis of the pin

[0139] α1 contact angle of the first contact position

[0140] α2 contact angle of the second contact position

Claims

1. A tripod joint (1) comprising a joint outer part (20) with a track pair (21), a tripod spider (10) with radially protruding pins (12), rolling elements (13) rotatably supported on the pins (12) of the tripod spider (10) around a longitudinal axis (Z) of the respective pin (12), wherein each rolling element (13) comprising an outer ring (14) with an outer periphery (14a) for rolling along the track pair (21) of the joint outer part (20), an inner ring (15) in contact with one pin (12) of the tripod spider (10) by its inner periphery (15a), and a needle (16) arranged around the pin (12) in an annular space (17) between an outer periphery (15b) of the inner ring (15) and an inner periphery (14b) of the outer ring (14), characterized in that the inner periphery (15a) of the inner ring (15) of the rolling element (13) has a head clearance (KS) relative to the surface of the pin (12) in the rotational direction (D) of the tripod spider (10) relative to the associated pin (12), which head clearance decreases towards two contact positions (K1, K2) on the pin (12) on either side of the rotational direction (D), wherein around the contact positions (K1, K2) a primary contact area (HK) is respectively formed and between the two primary contact areas (HK) a secondary contact area (NK) is located in the rotational direction (D), such that in the primary contact areas (HK) an increase in force transmission occurs compared to a circular cross-sectional profile and in the secondary contact area (NK) the force transmission is conversely reduced, wherein the contact angles a1 and a2 of the contact positions (K1, K2) on the pin (12) are defined in a plane perpendicular to the longitudinal axis (Z) of the pin (12), the contact angles being the angles between a straight line through the contact positions (K1, K2) and a point of passage (P) through said plane and a straight line through the point of passage (P) of said plane and the longitudinal axis (Z) in the rotational direction (D) of the tripod spider (10), wherein the contact angles a1 and a2 are in the range of 5° to 35°, wherein the head clearance KS is determined as follows depending on the maximum existing contact angle of the two contact positions (K1, K2): Ks = KSF * a / 1000 wherein KS is a value in millimeters, a is the maximum existing contact angle of the two contact positions (K1, K2) in degrees, and KSF is a value of 1 to 8.

2. The tripod gimbals (1) according to claim 1, characterized in that The contact angles a1 and a2 of the two contact positions (K1, K2) on either side of the rotational direction (D) are of the same magnitude.

3. The tripod gimbals (1) according to claim 1, characterized in that, The surface (12a) of the pin (12) has a flattened portion in cross-section between the two contact positions (K1, K2) on the side thereof facing the rotational direction (D).

4. The tripod gimbals (1) according to claim 1, characterized in that The surface (12a) of the pin (12) has a curved section (H) in cross-section between the two contact positions (K1, K2), the radius (R3) of the curved section being greater than the distance of the contact positions (K1, K2) from the longitudinal axis (Z) of the pin (12).

5. The tripronged gimbals (1) according to claim 4, characterized in that The curved section (H) transitions tangentially into two generated circles (E1, E2) for the contact locations (K1, K2), which tangentially contact the base circle (K) at the associated contact locations (K1, K2), wherein the radii (R1, R2) of the generated circles (E1, E2) are smaller than the radius (R3) of the curved section (H).

6. A tripod head (1) according to claim 4 or 5, characterized in that The curved section (H) is convexly curved.

7. A tripod head (1) according to claim 4 or 5, characterized in that The curved section (H) is concavely curved.

8. The tripod gimbals (1) according to claim 1, characterized in that, The outer peripheral portion (15b) of the inner ring (15) is cylindrical in the region of contact with the needle (16).

9. The tripod gimbals (1) according to claim 1, characterized in that, The surface (12a) of the pin (12) is designed as convexly spherical in a longitudinal section containing the longitudinal axis (Z) of the respective pin (12).

10. A method for manufacturing a tripod gimbals (1) according to any of the preceding claims 1 to 9, wherein, The star-tripod structure (10) is manufactured by means of forming technology, characterized in that the forming-technological manufacture of the star-tripod structure (10) is effected by means of a split mold, whose split surface (W) in the region of the pins (12) of the star-tripod structure is constituted by the longitudinal axis (Z) of the respective pin (12) and the axis of rotation (A) of the star-tripod structure (10), wherein the pin (12) is provided, in the forming-technological manufacture, with a cross section which, in a section perpendicular to the longitudinal axis (Z) of the pin (12), is non-circular and forms a flattening (18) in the direction of rotation (D) of the star-tripod structure (10).

11. The method of claim 10, wherein, The contour of the pin (12) is finally formed in the head gap (KS) region by means of forming technology.

12. The method according to claim 10 or 11, characterized in that The step of manufacturing by means of forming technology includes a partial calibration by means of forming technology only in the region of the contact locations (K1, K2) to produce the final contour of the surface of the pin (12).

13. The method according to claim 10 or 11, characterized in that The step of manufacturing by means of forming technology includes a calibration by means of forming technology in the region of the contact locations (K1, K2) and the head gap (KS) region to produce the final contour of the surface of the pin (12), wherein the material of the pin (12) is extruded into the region around the longitudinal axis (Z) of the pin (12) outside the contact locations (K1, K2).

14. The method of claim 10, wherein, The contour of the pin (12) is produced in the head gap (KS) region by means of post-processing of the calibration.

15. A method for manufacturing a tripod gimbals (1) according to any of the preceding claims 1 to 9, wherein the tripod star structure (10) is manufactured by a shaping technique, characterized in that, The forming-technological manufacture of the star-tripod structure (10) is effected by means of a split mold, wherein the axis of rotation (A) of the star-tripod structure (10) is perpendicular to the mold split surface (W), and the contour of the pin (12) is produced in the head gap region by means of post-processing of the calibration.

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