Counter track joint

Abstract

The present invention relates to a counter track joint having a joint outer portion (12) and a joint inner portion (13), wherein a first track pair (22A, 23A) is extended towards the opening side of the joint outer portion (12) in a straight counter track joint, and a second track pair (22B, 23B) is extended towards the connection side of the joint outer portion (12) in a straight counter track joint. The counter track joint further has one first ball (14A) in each first track pair, one second ball (14B) in each second track pair, and a ball retainer (15) provided with circumferentially distributed retainer windows (18) each accommodating one of the balls (14). The second outer track baseline (G22B) of the joint outer portion (12) extends radially inward of a second outer reference circular arc (CRB12) defined by a second outer radius (R22Bp) forming the second outer track baseline (G22B) in a second offset plane (EB) from a track bending angle (β') of at least ±20° when viewed in the direction starting from the joint center plane (EM) and towards the joint bottom (19).

Description

Technical Field

[0001] The present invention relates to a constant velocity joint in the form of a counter track joint.

[0002] Based on German Patent Application Publication No. 10060120, a counter track joint is known that includes an outer joint portion with a curved outer track, an inner joint portion with a curved inner track, balls accommodated in the outer track and the inner track, and a ball retainer having a retainer window in which the balls are held. The first outer track and the first inner track form a first track pair. The first control angle of the first track pair is open in the first axial direction, and a first ball is held in the first track pair. The second outer track and the second inner track form a second track pair. The second control angle of the second track pair is open in the second axial direction, and a second ball is held in the second track pair. The outer joint portion and the inner joint portion are slidable relative to each other in the axial direction.

[0003] Based on International Publication No. 2013 / 029655, another counter track joint is known. In a straight joint, the first track pair opens towards the opening side, and the second track pair opens towards the connection side. The control angle of the first track pair is larger than the control angle of the second track pair. The first center point line of the first track pair in the outer joint portion extends radially inward of the reference arc in the direction towards the connection side and radially outward of the reference arc in the direction towards the opening side.

[0004] Based on German Patent Application Publication No. 10337612, a counter track joint is known in which a track pair that opens towards the bottom has an opening angle that first becomes zero at the location of the balls that enter the outer joint portion beyond the central plane during joint bending and then opens towards the opening side.

[0005] Based on US Patent Application Publication No. 2007 / 0111806, which corresponds to International Publication No. 2006 / 048032, another counter track joint is known. In a straight joint, the ball track that opens towards the connection side in the joint center plane has a first arc section with a small radius on the connection side, a second arc section with a larger radius in the region of the joint center plane, and a third arc section on the opening side. The third arc section has a curvature in the opposite direction to the second arc section.

[0006] Based on German Patent Application Publication No. 10304156, a counter track joint with eight balls is known. In this counter track joint, the second outer ball track has an assembly extension for inserting the second ball into the cage window from the radially outer side at the opening of the outer part of the joint. The second ball is inserted when the first ball is already fully equipped in the first cage window. For insertion, the joint is overbent and the second cage window extends from the outer part of the joint.

[0007] Based on International Publication No. 2007 / 079762, a counter track joint for a large bending angle is known.

[0008] The problem underlying the present invention is to propose a constant velocity joint, in particular a constant velocity joint for a small bending angle, which has a slight weight or high efficiency and can be manufactured inexpensively in order to contribute to CO2 reduction as a whole.

[0009] According to the present invention, a constant velocity joint in the form of a counter track joint having the features of claim 1 is proposed. Further possible embodiments will become apparent from the dependent claims.

[0010] The inner part of the joint is angularly movable relative to the outer part of the joint over a primary joint bending angle region and a secondary joint bending angle region following this primary joint bending angle region. The primary joint bending angle region defines a bending angle region in which the first or second ball moves internally along during the operation of the joint. In this regard, the primary joint bending angle can also be referred to as the operating bending angle. The maximum primary joint bending angle is defined as the bending angle at which all the balls are just still involved in torque transmission between the outer part and the inner part of the joint before the first or second ball moving towards the opening side exits from the track pair it belongs to on the opening side. When bending the joint within the operating bending angle region, the first and second balls move up to the maximum primary track bending angle within the corresponding track bending angle region. The maximum primary joint bending angle may particularly be less than ±30°, that is, during operation, the inner part of the joint can be bent relative to the outer part of the joint by a maximum of this absolute value. The second ball moves up to the maximum primary track bending angle along the primary track part of the outer part of the joint within the primary track bending angle region during operation. The maximum primary track bending angle is preferably less than ±20° centered on the joint center plane, particularly less than ±15°.

[0011] A secondary track bending angle region follows in the direction of the joint bottom to the primary track bending angle of the second outer ball track. The first or second ball moves into the secondary track bending angle region only during the assembly of the joint, that is, during over-bending. In this regard, the secondary joint bending angle can also be referred to as the assembly bending angle.

[0012] The track baseline of the first outer ball track has a first maximum radial spacing with respect to the longitudinal axis in a first offset plane (EA) parallel to the joint center plane (EM) within the operating flexion angle. The track baseline of the second outer ball track has a second maximum radial spacing with respect to the longitudinal axis in a second offset plane (EB) parallel to the joint center plane (EM) within the operating flexion angle. An offset plane intersection (PEB) is defined between the bottom-side second offset plane and the second outer track baseline (G22B). A reference arc (CRB12) of the second outer ball track is defined by the track radius forming the second outer track baseline (G22B) in the second offset plane (EB). According to the present invention, the second outer track baseline (G22B) is defined to extend radially inward of the second outer reference arc (CRB12) from a track flexion angle of at least ±15° when viewed in the direction from the joint center plane (EM) toward the joint bottom when bending the joint.

[0013] One advantage of the counter track joint is that it can be well used for applications with a small operating flexion angle. By configuring the second ball track of the outer part of the joint such that the track baseline of this second ball track already extends radially inward of the outer reference arc from a track flexion angle of ±15° on the bottom side, the ball in question moves radially inward with a greater curvature when the joint is over-flexed. This provides a small-angle counter track joint with special assembly features. Overall, this outer part of the joint enables a small axial length, which results in material savings and a slight weight. Therefore, this joint has high efficiency, can be manufactured inexpensively, and contributes to overall CO2 reduction.

[0014] According to one embodiment, the inner surface of the outer joint portion may form, on the connection side, a support surface that can support the ball retainer in the axial direction during assembly. For this purpose, the spherical surface of this joint component member is such that the equator of the spherical inner surface of the outer joint portion and the equator of the spherical retainer outer surface are located in one plane, and the equator of the spherical retainer inner surface and the equator of the spherical outer surface of the inner joint portion are located in one plane. In the assembled state of the joint, the outer radial gap may be formed to be larger in the direction of the connection side than in the direction of the opening side. Thereby, when the shaft is press-fitted via the ball retainer, the inner joint portion can be supported in the axial direction by the outer joint portion without the balls being caught in the ball track.

[0015] According to one embodiment, the track base line (G22B) of the second outer ball track may have a first curvature in the first track portion and a second curvature in the second track portion, respectively. Since the second curvature is preferably smaller than the first curvature, the ball track extends radially inward earlier on the bottom side and has a shorter axial extension length. According to a possible embodiment, the second outer track base line (G22B) may be formed by an arc having a first radius (R22Bp) centered on a first center point (MBp) in the first track portion and an arc having a second radius (R22Bs) centered on a second center point (MBs) in the second track portion. In this case, the second radius is preferably smaller than the first radius. The second center point (MBs) has a radial deviation in the direction of the ball track with respect to the longitudinal axis (L12) of the outer joint portion and / or an axial deviation in the direction of the joint bottom with respect to the joint center plane (EM), and may be arranged, for example, in the second offset plane (EB).

[0016] Starting from the second offset plane (EB), the primary track portion of the second outer ball track has a primary track portion on the opening side between the second offset plane (EB) and the end on the opening side. This primary track portion on the opening side extends over an opening-side track portion angle (γB1) smaller than 23° around the track portion center point (MBp). A primary track portion on the bottom side is formed between the second offset plane (EB) and the end on the bottom side of the primary track portion, and this primary track portion on the bottom side extends over a bottom-side track portion angle (γB2) smaller than 12° around the track portion center point (MBp). With this configuration, the primary track portion of the second outer ball track is relatively short as a whole.

[0017] The outer secondary baseline radius (RMGs) from the joint center point (M) to the track baseline (G22B) within the secondary track portion of the second outer ball track (22B) is defined. According to one embodiment, the outer secondary baseline radius (RMGs) is smaller than 1.45 times the rolling circle radius (PCRB) of the second ball in a straight joint, particularly at a joint bending angle of at least ±40° to ±50°, or smaller than 1.4 times the rolling circle radius (PCREB) in the second offset plane (EB) of the outer portion of the joint.

[0018] The second ball track (23B) in the inner portion of the joint has a second inner primary track portion and a second inner secondary track portion that follows the second inner primary track portion on the opening side. The second ball moves along the second inner primary track portion up to the maximum primary bending angle during angular movement within the primary bending angle region. During greater angular movement, that is, from the secondary bending angle region, the second ball moves within the second inner secondary track portion. According to one embodiment, the second inner ball track has a second inner track baseline (G23B), and this second inner track baseline is curved convexly within the second inner primary track portion and at least partially concavely within the second inner secondary track portion and / or is straight.

[0019] In the inner part of the joint, an inner secondary baseline radius (RMGs’) from the joint center point (M) to the track baseline (G23B) in the inner secondary track part may be defined. The inner secondary baseline radius (RMGs’) may be smaller than 1.45 times the rolling circle radius (PCRB) of the second ball in a straight joint at least at joint flexion angles of ±40° to ±50°, or may be smaller than 1.5 times the rolling circle radius (PCREB’) in the second offset plane (EB’) of the inner part of the joint.

[0020] According to a preferred embodiment, the primary joint flexion angle is smaller than 0.5 times the minimum second assembly flexion angle at which the second ball can be inserted into the second track pair. The minimum second assembly flexion angle may be greater than 60°, for example.

[0021] The first outer ball track (22A) may form a first undercut (HA) on the opening side, and the second outer ball track (22B) may form a second undercut (HB) on the opening side. According to a preferred embodiment, the first undercut of the first ball track opening towards the opening side is smaller than the second undercut of the second ball track opening towards the connection side. For example, the second outer undercut (HB) may be greater than 5 times the first outer undercut (HA).

[0022] Regarding the production of a counter track joint, various different embodiments are possible. The outer joint part and the inner joint part can be produced in a method sequence of forming a preform by forging a blank, hardening the forged preform, and mechanically finishing the hardened preform by, for example, turning and / or grinding. Alternatively, at least one of the outer ball track group and the inner ball track group can be finished before hardening (which can be achieved, for example, by deformation processing), that is, it is possible that it is not mechanically processed after hardening. This includes that both the inner joint part and the outer joint part of the joint are finished with respect to the pre-hardening shaping before hardening. However, it also includes that only one of the two joint parts is soft-finished, and the other joint part, that is, one of the outer ball track group and the inner ball track group, is hardened and hard-finished. The hard-finishing can be, for example, a cutting-type processing by turning and / or grinding. The counter track joint provided with at least one soft-finished joint part has the advantage that it can be manufactured at low cost based on the ball track group finished before hardening. The counter track joint provided with one soft-finished joint part and one hard-finished joint part, in addition to this advantage, provides the advantage that, based on the ball track group hardened and then hard-finished, the support surface of the outer joint part, and the counter track shape, a good guiding function and a supporting function for the ball retainer, and thus high efficiency are provided.

[0023] The number of balls for transmitting torque, and accordingly the number of outer and inner ball tracks, is preferably divisible by 2, and in particular is 8. Different numbers such as 6 or 10 are also possible.

[0024] Hereinafter, preferred embodiments will be described based on the drawings.

Brief Description of the Drawings

[0025]

Figure 1A

Figure 1B

Figure 1C

Figure 1D

Figure 2A

Figure 2B

Figure 3A

Figure 3B

Figure 4A

Figure 4B

Figure 4C

Figure 4D

Figure 5A

Figure 5B

Figure 5C

Figure 5D

Figure 6A

Figure 6B

Figure 6C

[0026] FIGS. 1A to 6C, which will be described together below, show a counter track joint 11 according to the present invention. The counter track joint 11 has a joint outer portion 12, a joint inner portion 13, a plurality of balls 14A, 14B for transmitting torque, and a ball cage 15. A clearance may be provided in the assembled state between the spherical outer surface 16 of the ball cage 15 and the spherical inner surface 24 of the joint outer portion 12. A circumferentially extending gap 27 is formed in the assembled state between the spherical inner surface 17 of the ball cage 15 and the spherical outer surface 26 of the joint inner portion 13. In the present embodiment, the surface center points M16 and M17 are located within a common joint center plane EM. In a modified configuration, it is also possible for the surface center points M16 and M17 to have an axial distance (offset) in directions opposite to each other with respect to the joint center plane EM. The balls 14A, 14B are held within the cage windows 18 distributed in the circumferential direction in the ball cage 15 within the joint center plane EM. A longitudinal axis L12 is shown in the joint outer portion 12, and a longitudinal axis L13 is shown in the joint inner portion 13. The intersection points of the longitudinal axes L12, L13 and the joint center plane EM form the joint center point M.

[0027] In the embodiment shown herein, the inner surface 24 of the joint outer portion 12, the outer surface 16 of the cage, the inner surface 17 of the cage, and the outer surface 27 of the joint inner portion 13 are formed in a spherical shape. Alternatively or additionally, one or more of the above-described surfaces may have a cylindrical, toroidal, and / or conical section. With respect to the inner surface 24 of the outer portion 12, an opening-side section 24a, a central section 24c, and a bottom-side section 24b are drawn in FIG. 2A. The bottom-side section 24b may form a support surface, and when the joint shaft is inserted into the joint inner portion 13, the ball cage 15 can be supported axially on this support surface by its outer surface 16.

[0028] The joint outer portion 12 has, for example, a bottom 19 that may transition to a connection pin 25 and an opening 20. The joint inner portion 13 has an opening 21, and a pin of a drive shaft 30 for transmitting torque can be inserted into the opening 21 in a non-rotatable manner. In the present disclosure, the position of the bottom 19 is referred to as the axial direction "towards the connection side", and the position of the opening 20 is referred to as the axial direction "towards the opening side". These terms are also used with respect to the joint inner portion 13, and in this case, the actual connection of the shaft to the joint inner portion is not considered.

[0029] A first track pair 22A, 23A having a first ball 14A for transmitting torque and a second track pair 22B, 23B having a second ball 14B for transmitting torque are alternately provided over the entire circumference. The first track pair 22A, 23A is shown in FIG. 1A, and the second track pair 22B, 22B is shown in FIG. 1B. The first ball 14A is in contact with a first outer ball track 22A in the outer joint portion and a first inner ball track 23A in the inner joint portion. In this case, when the center point of the first ball 14A moves along the outer first ball track 22A and the inner first ball track 23A, it defines a first center point line A respectively, while the center point of the second ball 14B defines a second center point line B respectively when moving along the outer second ball track 22B and the inner second ball track 23B. The center point lines A and B are written in FIGS. 3A and 3B. Further, the outer first ball track 22A has an outer first track base line G22A, the inner first ball track 23A has an inner first track base line G23A, the outer second ball track 22B has an outer second track base line G22B, and the inner second ball track 23B has an inner second track base line G23B respectively.

[0030] When the joint outer portion 12 and the joint inner portion 13 are coaxially oriented, the tangents T22A, T23A to the ball 14A form an opening angle δA that opens toward the opening side at the contact points with the first tracks 22A, 23A. The second ball 14B is guided by the outer ball track 22B in the joint outer portion 12 and the inner ball track 23B in the joint inner portion 13. The ball 14B is shown in contact with the track base of the ball track, but the contact does not necessarily have to occur. At the illustrated position where the joint is straightened, the tangents T22B, T23B to the second ball 14B form a second opening angle δB that opens toward the connection side at the contact points with the second tracks 22B, 23B. When the track shape of the counter track joint is changed, opening angles directed in opposite axial directions can occur, especially at the position of a slightly bent joint of up to 2°.

[0031] The number of balls 14A, 14B for transmitting torque or the number of outer ball tracks 22A, 22B and inner ball tracks 23A, 23B is 8 in this embodiment. However, alternative embodiments with a different number of balls or ball pairs divisible by 2, such as 6 or 10, are also possible. The two first track pairs 22A, 23A of the joint outer portion 12 and the joint inner portion 13 are positioned opposite each other in the diametrical direction, and the two second track pairs 22B, 23B are positioned opposite each other in the diametrical direction.

[0032] The first track pair and the second track pair are located in a radial plane passing through the joint with their center lines, but are not limited to this form. These track pairs may extend slightly spirally about their longitudinal axes. One ball 14A, 14B is respectively accommodated in the retainer window 18 in the ball retainer 15. The radial planes have equal angular intervals with respect to each other.

[0033] Next, the features of the counter track joint 11 according to the present invention will be described in more detail, particularly with respect to the configuration of the second ball track 22B of the joint outer portion 12 and the configuration of the second ball track 23B of the joint inner portion 13. In the context of the present disclosure, the following definitions apply.

[0034] The joint bending angle β defines the angle formed between the longitudinal axis L12 of the joint outer portion 12 and the longitudinal axis L13 of the joint inner portion 13. The joint bending angle β is zero in a straight joint.

[0035] The track bending angle β' defines the angle formed by the radius from the joint center point M to the ball center with the joint center plane EM. In this case, the track bending angle β' is always half of the joint bending angle β (β' = β / 2) at any angular position of the joint.

[0036] The track portion angle γ of the arc-shaped track portion defines the angle of the range in which this arc-shaped track portion extends with a constant radius about the corresponding radius center point.

[0037] The mouth opening angle δ defines the angle formed at the contact point with the first ball track or the second ball track by the tangent T to the ball in a straight joint.

[0038] The control angle δ / 2 defines the angle formed by the tangent that contacts each ball center point line at the ball center point with the longitudinal axis L belonging to the joint outer portion or the joint inner portion in a straight joint. In this case, the control angle δ / 2 is equal to half of the mouth opening angle δ.

[0039] The center point plane EM is defined by the ball center points of the balls 14A, 14B that transmit torque.

[0040] The first pitch circle diameter PCDA defines the diameter formed by the center points of the plurality of first balls 14A in a straight joint. Similarly, the first pitch circle radius PCRA results as the radius of the plurality of first balls to the center point.

[0041] The second pitch circle diameter PCDB defines the diameter formed by the center points of the plurality of second balls 14B in a straight joint. Similarly, the second pitch circle radius PCRB results as the radius of the plurality of second balls to the center point.

[0042] The pitch circle diameter PCDS defines the diameter of the insertion opening of the inner joint portion 13, particularly by the tooth base line of the insertion opening.

[0043] The counter track joint 2 is designed such that the inner joint portion 13 can be bent with respect to the outer joint portion 12 over a primary joint bending angle region βp and a secondary joint bending angle region βs following this primary joint bending angle region βp. The primary joint bending angle region defines the bending angle region in which the first ball 14A or the second ball 14B moves internally during the operation of the joint. In this regard, the primary joint bending angle βp can also be referred to as the operating bending angle. The maximum primary joint bending angle is defined as the bending angle at which all the balls 14A, 14B are just still involved in the torque transmission between the outer joint portion 12 and the inner joint portion 13 before the first or second ball moving towards the opening side exits from the track pair to which it belongs on the opening side. When bending the joint within the operating bending angle region βp, the first ball 14A moves correspondingly within the first track bending angle region β’Ap. Here, the maximum primary track bending angle on the bottom side of the first outer ball track 22A is denoted by the symbol β’Am. The second ball 14B moves within the second track bending angle region β’Bp during operation. Here, the maximum primary track bending angle on the bottom side of the second outer ball track 22B is denoted by the symbol β’Bm.

[0044] The first joint bending angle region βp is preferably less than ±30°, for example ±25°. That is, starting from the straight state, during operation, the inner part of the joint can be bent with respect to the outer part of the joint by up to ±30° or less. The second ball 14B moves along the first track portion 22Bp of the outer part 12 of the joint within the first track bending angle region β’Bp to a maximum first track bending angle β’Bm during operation. The maximum first track bending angle β’Bm is less than ±20°, particularly less than ±15°, for example ±12.5° about the joint center plane EM.

[0045] The second track bending angle region β’Bs follows the first track bending angle β’Bp of the second outer ball track 22B in the direction of the joint bottom 19. The first ball 14A or the second ball 14B moves into the second track bending angle region only when the balls positioned opposite each other in the diameter direction are incorporated. In that regard, the second joint bending angle region βs includes the meaning of the incorporated bending angle.

[0046] The track base line G22A of the first ball track 22A of the outer part 12 of the joint has a first maximum radial distance with respect to the longitudinal axis L12 in the first offset plane EA parallel to the joint center plane EM within the track bending angle β’Ap. The track base line G22B of the second ball track 22B has a second maximum radial distance with respect to the longitudinal axis L12 in the second offset plane EB parallel to the joint center plane EM within the track bending angle β’Bp. An offset plane intersection PEB shown in Fig. 2A is defined between the second offset plane EB on the bottom side and the second outer track base line G22B.

[0047] The reference circular arc CRB12 of the second outer ball track 22B is defined by the track radius R22Bp that forms the second outer track base line G22B in the second offset plane EB. According to the present invention, the second outer track base line G22B is defined to extend radially inward of the second outer reference circular arc CRB12 from a track bending angle β’B of at least ±20°, for example ±15°, when viewed in the direction toward the joint bottom 19 when bending the joint. In FIG. 2B, a baseline radius RMGs is written between the joint center point M and the track base line G22B in the secondary track portion 22Bs. The second ball tracks 22B, 23B are configured such that the baseline radius RMGs is less than 1.45 times the rolling circle radius PCRB of the second ball 14B in a particularly straight joint and / or less than 1.4 times the rolling circle radius PCREB of the second ball 14B in the offset plane EB at a joint bending angle β corresponding to a track bending angle of at least ±20° to ±25°, i.e., ±40° to ±50°.

[0048] As particularly recognized in FIG. 2A, the track base line G22B of the second outer ball track 22B has a first curvature R22Bp within the first track portion 22Bp and a second curvature R22Bs within the second track portion 22Bs, respectively. Since the second curvature R22Bs is smaller than the first curvature R22Bp, the ball track 22B extends radially inward earlier at the bottom side. Therefore, the joint outer portion 12 in this circumferential region can be configured to be shorter when viewed in the axial direction. The curvature of the second outer track base line G22B may be formed by an arc having a first radius R22Bp centered on the first center point MBp within the first track portion. The track base line G22B may be formed by an arc having a second radius R22Bs centered on the second center point MBs within the second track portion. In this case, the second radius R22Bs is smaller than the first radius R22Bp. The second center point MBs has a radial deviation in the direction of the ball track 22B with respect to the longitudinal axis L12 of the joint outer portion 12 and an axial deviation in the direction of the joint bottom 19 with respect to the joint center plane EM, and may be located, for example, within the second offset plane EB.

[0049] Starting from the second offset plane EB, the first track portion 22Bp of the second ball track 22B of the joint outer portion 12 has a first track portion on the opening side between the second offset plane EB and the end portion on the opening side. This first track portion on the opening side extends over an opening-side track portion angle γBp1 that is particularly less than 23° about the track portion center point MBp. A first track portion on the bottom side is formed between the second offset plane EB and the end portion on the bottom side of the first track portion, and this first track portion on the bottom side extends over a bottom-side track portion angle γBp2 that is particularly less than 12° about the track portion center point MBp.

[0050] Further details of the outer joint portion 12 are shown in FIGS. 3A and 3B, which are also collectively referred to as FIG. 3. It can be seen that the first outer bolt track 22A forms a first undercut HA on the opening side 20, and the second outer bolt track 22B forms a second undercut HB on the opening side 20. The first undercut HA of the first bolt track 22A that opens towards the opening side is particularly smaller than the second undercut HB of the second bolt track 22B that opens towards the connection side. For example, the second outer undercut HB may be more than five times the first outer undercut HA.

[0051] The inner joint portion 13 of the counter track joint 11 according to the present invention is shown in FIGS. 4A to 4D, which are also collectively referred to as FIG. 4. In this case, while the first bolt track 23A that expands towards the opening side defines a first center point line A', the second bolt track 23B that opens towards the connection side defines a second center point line B' of the inner joint portion 13.

[0052] In this case, the first ball center point line A' of the inner joint portion 13 is complementarily configured with respect to the first ball center point line A of the outer joint portion 12. That is, with respect to the joint center plane EM, the ball center point line A' of the inner joint portion 13 and the ball center point line A of the outer joint portion 12 are mirror images of each other. Correspondingly, the second ball center point line B' of the inner joint portion 13 is complementary to the second ball center point line B of the outer joint portion 12. That is, with respect to the joint center plane EM, the second ball center point line B' of the inner joint portion 13 and the ball center point line B of the outer joint portion 12 are mirror images of each other. To that extent, regarding the track extension of the first ball center point line A' and the second ball center point line B' of the inner joint portion 13, refer also to the description given in relation to the outer joint portion 12. In FIG. 4D, a first offset plane EA' is drawn on the inner joint portion 13. This first offset plane EA' corresponds to, or overlaps with, the second offset plane EB of the outer joint portion 12 when the joint is assembled and straightened. The second offset plane EB' of the inner joint portion 13 corresponds to the first offset plane EA of the outer joint portion 12 in the assembled and straightened joint.

[0053] The second ball track 23B of the inner joint portion 13 has a primary track portion 23Bp and a secondary track portion 23Bs that follows the primary track portion 23Bp on the opening side. The second ball 14B moves along the primary track portion 23Bp of the inner portion to a maximum primary bending angle during angular movement within the primary bending angle region. During greater angular movement, that is, from the secondary bending angle region, the second ball 14B moves within the secondary track portion 23Bs. Particularly in FIG. 4D, the second inner ball track 23B has a second inner track baseline G23B, and this second inner track baseline G23B is formed convexly within the primary track portion 23Bp as seen in the longitudinal section of the track base, and is at least partially curved concavely and / or straight within the secondary track portion 23Bs. In this case, the secondary track portion 23Bs forms a recess that is radially recessed in the direction of the opening side.

[0054] An inner baseline radius RMGs' from the joint center point M to the track baseline G23B within the inner secondary track portion 23Bs may be defined in the inner joint portion 13. The inner baseline radius RMGs' may be less than 1.45 times the rolling circle radius PCRB of the second ball 14B in a straight joint at least at a joint bending angle β of ±40° to ±50° corresponding to a track bending angle of ±20° to ±25°, and / or may be less than 1.5 times the rolling circle radius PCREB' in the second offset plane EB' of the inner joint portion 13.

[0055] According to a preferred embodiment, the primary joint bending angle βp is less than 0.5 times and / or greater than 0.35 times the minimum second assembly bending angle βBs at which the second ball can be inserted into the second track pair. The same ratio also applies to the cage operating bending angle with respect to the cage assembly bending angle. The minimum second joint assembly bending angle βBs may be greater than, for example, ±50° or ±60°.

[0056] The ball cage 15 is shown as a single unit in FIGS. 5A to 5D. Cage windows 18 distributed in the circumferential direction, a spherical outer surface 16, and a spherical inner surface 17 are recognized, and in the present embodiment, these are arranged coaxially with each other. The outer surface 16 of one ball cage 15 and the inner surface 24 of the joint outer portion 12, and the inner surface 17 of the other ball cage and the outer surface 26 of the joint inner portion 13 are such that, particularly when the counter track joint 11 is assembled and straightened, the total axial play So between the ball cage 15 and the joint outer portion 12 and the total axial play Si between the ball cage 15 and the joint inner portion 13 are made to have different sizes respectively. In the present embodiment, the total outer axial play is smaller than the total inner axial play. Further, the spherical surfaces 24, 16, 17, 26 of the joint components 12, 13, 15 are such that the equator of the spherical surface 26 of the joint outer portion 12 and the equator of the spherical cage outer surface 16 are located in one plane, and the equator of the spherical cage inner surface 17 and the equator of the spherical surface 26 of the joint inner portion 13 are located in one plane. In the assembled state of the joint 11, the outer axial play and the radial play may be configured to be smaller than the inner axial play or the radial play. The spherical outer surface 16 and the inner surface 17 of the ball cage 15 may be soft-finished and then hardened. The soft processing of the surfaces 16, 17 may be performed by a cutting method, for example, turning or grinding, and / or by a non-cutting method, for example, deformation processing. The walls of the cage windows 18 that guide the balls 14A, 14B laterally are preferably hardened by hard processing, particularly grinding, after hardening.

[0057] The counter track joint 2 according to the present invention, having eight balls 14A, 14B as shown in FIGS. 1 to 6 and having an operating bending angle of, for example, ±20° to ±30°, particularly has a compact structural size when the following ratios or ranges of individual dimensional parameters are observed. 3.4 < PCD / DB < 3.7 1.05 < LIR / DB < 1.35 0.30 < TIR / DB < 0.5 1.6 < PCDS / DB < 1.8 2.9 < DOR / PCDS < 3.2 0.24 < TC / DB < 0.28 1.6 < LC / DB < 1.9 1.15 < RMGs / PCRB < 1.4 2.0 < βBs / βp < 2.8 18° < γB1 < 23° 2° < γB2 < 12° 2° < γA1 < 10° 5 < HB / HA < 10

[0058] Here, each of the above parameters has the following meanings. βBs: Joint assembly bending angle for the second track pair βp: Joint operation bending angle DB: Ball diameter DOR: Outer diameter of the joint outer part HA: Undercut of the first ball track (joint outer part) HB: Undercut of the second ball track (joint outer part) LC: Retainer length LIR: Axial length of the joint inner part PCD: Pitch circle diameter of the balls PCDS: Pitch circle diameter of the shaft spline PCRB: Rolling circle radius of the balls in track B RMGs: Radius from the joint center to the track base of the secondary track part of track B TC: Retainer thickness TIR: Thickness of the joint inner part

[0059] Figures 6A and 6B show the counter track joint in two built-in states of the balls. For this purpose, the inner joint part 13 is overbent to the assembly bending angle βs with respect to the outer joint part. As shown in Figure 6B, first, the second ball 14B is inserted into the second ball tracks 22B, 23B. Then, as shown in Figure 6A, the first ball 14A is inserted into the first ball tracks 22A, 23A. Figure 6C shows the counter track joint 2 at the operating bending angle βp corresponding to the track bending angle βp'.

[0060] A plurality of manufacturing methods are possible. The outer joint part 12 and the inner joint part 13 can be in the order of pre-forging of the blank, hardening of the forged preform, and mechanical finishing of the hardened preform, such as turning and / or grinding. Alternatively, at least one of the outer joint part 12 and the inner joint part 13 can be finished, for example, by deformation processing before hardening. In this case, no further mechanical processing for shaping is performed after hardening. According to another possibility, both joint parts 12, 13 can be hardened and finished, for example, by turning and / or grinding after hardening.

Explanation of Reference Signs

[0061] 11 Counter track joint 12 Outer joint part 13 Inner joint part 14A, 14B Balls 15 Ball retainer 16 Outer surface (15) 17 Inner surface (15) 18 Window 19 Connection side 20 Opening side 21 Opening 22A, 22B Outer ball tracks 22Bp Primary track part 22Bs Secondary track part 23A, 23B Inner ball tracks 24 Inner surface (12) 25 Outer gap 26 Outer surface (13) 27 Inner gap 28 Radial extension 29 Pocket 30 Shaft 31 Recess 32 Web (12) 33 Web (13) 34 Extension 35A, 35B Chamfer 36 Opening β Joint bending angle β’ Track bending angle δ Mouth opening angle γ Track part angle CRB Reference circular arc EA Offset plane (22A) EA’ Offset plane (23A) EB Offset plane (22B) EB’ Offset plane (23B) EM Joint center plane G Track baseline L Longitudinal axis M Joint center point PEB Offset plane intersection point PCD Rolling circle diameter PCR Rolling circle radius R Radius RMG Baseline radius T Tangent Si Inner total axial play So Outer total axial play

Claims

1. A counter track joint, comprising: A joint outer portion (12) having a longitudinal axis (L12), a joint bottom (19) defining a connection side, an opening (20) defining an opening side, a first outer ball track (22A) and a second outer ball track (22B), wherein the first outer ball track (22A) and the second outer ball track (22B) are circumferentially distributed and arranged on the inner surface (24) of the joint outer portion (12) and are at least partially curved in a longitudinal cross-section, the joint outer portion (12); A joint inner portion (13) having a longitudinal axis (L13), a first inner ball track (23A) and a second inner ball track (23B), wherein the first inner ball track (23A) and the second inner ball track (23B) are circumferentially distributed and arranged on the outer surface (26) of the joint inner portion (13) and are at least partially curved in a longitudinal cross-section, the joint inner portion (13); And having The first outer ball track (22A) and the first inner ball track (23A) form a first track pair that expands toward the opening side of the joint outer portion (12); The second outer ball track (22B) and the second inner ball track (23B) form a second track pair that expands toward the connection side. The second outer ball track (22B) has a second outer track baseline (G22B), a second outer primary track portion (22Bp), and a second outer secondary track portion (22Bs) following the second outer primary track portion (22Bp); The counter track joint Has one first ball (14A) in each of the first track pairs and one second ball (14B) in each of the second track pairs; A ball retainer (15) disposed between the joint outer portion (12) and the joint inner portion (13), having an inner surface (17) of the retainer, an outer surface (16) of the retainer, and circumferentially distributed retainer windows (18) each accommodating at least one of the balls (14A, 14B), wherein when the longitudinal axis (L13) of the joint inner portion (13) and the longitudinal axis (L12) of the joint outer portion (12) are coaxially oriented, the balls (14A, 14B) are retained by the ball retainer (15) in a joint center plane (EM), a ball retainer (15), further having, the joint inner portion (13) is angularly movable relative to the joint outer portion (12), and the second ball (14B) moves along the second outer primary track portion (22Bp) within a primary track bending angle region (β'Bp) up to a maximum primary track bending angle (β'Bm) of ±20° about the joint center plane (EM), where a maximum primary joint bending angle is defined as the joint bending angle (β) at which all the balls (14A, 14B) are just still involved in torque transmission between the joint outer portion (12) and the joint inner portion (13) before the balls (14A, 14B) moving towards the opening side exit from the track pair to which they belong on the opening side, the second outer track baseline (G22B) has a maximum radial spacing with respect to the second longitudinal axis (L12) in a second offset plane (EB) parallel to the joint center plane (EM) within the second outer primary track portion (22Bp), and a second offset plane intersection point (PEB) is defined between the second offset plane (EB) and the second outer track baseline (G22B), a second outer radius (R22Bp) forming the second outer track baseline (G22B) in the second offset plane (EB) defines a second outer reference arc (CRB12), The second outer track base line (G22B) extends radially inward of the second outer reference circular arc (CRB12) from a track bending angle (β') of at least ±20° when viewed in the direction from the joint center plane (EM) toward the joint bottom (19). Counter track joint. **Claim 2** The counter track joint according to claim 1, characterized in that the second outer track base line (G22B) extends radially inward of the second outer reference circular arc (CRB12) within a secondary track bending angle region (β'Bs) following the primary track bending angle region (β'Bp) by at least ±25° when viewed in the direction toward the joint bottom (19). **Claim 3** The counter track joint according to claim 1 or 2, characterized in that the second outer track base line (G22B) has a primary curvature within the primary track portion (22Bp) and a secondary curvature within the secondary track portion (22Bs), and the secondary curvature is smaller than the primary curvature. **Claim 4** The second outer track base line (G22B) is formed by an arc having a primary radius (R22Bp) centered on a primary center point (MBp) within the primary track portion (22Bp), and is formed by an arc having a secondary radius (R22Bs) centered on a secondary center point (MBs) within the secondary track portion. The secondary radius is smaller than the primary radius. In the outer joint portion (12), the secondary center point (MBs) has a radial deviation in the direction of the second ball track (22B) with respect to the longitudinal axis (L12) of the outer joint portion (12), and has an axial deviation in the direction of the joint bottom (19) with respect to the joint center plane (EM). The counter track joint according to any one of claims 1 to 3, characterized by the above. **Claim 5** The second outer ball track (22B) defines a primary track portion on the opening side between the second offset plane (EB) and the end portion on the opening side of the primary section, and the primary track portion on the opening side extends over an opening-side track portion angle (γB1) that is greater than 18° and less than 23° about the track portion center point (MBp). The counter track joint according to any one of claims 1 to 4, characterized in that.

6. The second outer ball track (22B) defines a primary track portion on the bottom side between the second offset plane (EB) and the end portion on the bottom side of the primary track portion (22Bp), and the primary track portion on the bottom side extends over a bottom-side track portion angle (γB2) that is greater than 2° and less than 12° about the track portion center point (MBp). The counter track joint according to any one of claims 1 to 5, characterized in that.

7. The outer secondary baseline radius (RMGs) from the joint center point (M) to the track baseline (G22B) in the secondary track portion (22Bs) of the second outer ball track (22B) is less than 1.45 times the rolling circle radius (PCRB) of the second ball (14B) in the straight joint at a secondary joint bending angle of at least ±40° to ±50°. The counter track joint according to any one of claims 1 to 5, characterized in that.

8. The second ball track (23B) of the inner joint portion (13) has a second inner primary track portion (23Bp) and a second inner secondary track portion (23Bs) that follows the second inner primary track portion (23Bp) on the opening side. The second ball (14B) moves along the second inner primary track portion (23Bp) up to a maximum primary bending angle (β’Bm) during angular movement within the primary track bending angle region (β’Bp), and moves within the second inner secondary track portion (23Bs) during greater angular movement within the secondary track bending angle region (β’Bs). The second inner ball track (23B) has a second inner track base line (G23B), and the second inner track base line (G23B) is convex within the second inner primary track portion (23Bp) and at least partially concave or straight within the second inner secondary track portion (23Bs). The counter track joint according to any one of claims 1 to 7, characterized in that.

9. The inner secondary base line radius (RMGs) from the joint center point (M) to the second inner track base line (G23B) within the second inner secondary track portion (23Bs) is less than 1.45 times the rolling circle radius (PCRB) of the second ball (14B) in a straight joint at a secondary joint bending angle of at least ±40° to ±50°. The counter track joint according to claim 8, characterized in that.

10. The first outer ball track (22A) defines an opening-side primary track portion between the first offset plane (EA) and the end of the opening side of the primary track portion (22Ap). The opening-side primary track portion extends over an opening-side track portion angle (γA1) that is greater than 2° and less than 10° centered on the track portion center point (MAp). The counter track joint according to any one of claims 1 to 5, characterized in that.

11. The primary joint bending angle (βp) is less than 0.5 times the minimum second joint assembly bending angle (βBs) at which the second ball (14B) can be inserted into the second track pair, and the minimum second joint assembly bending angle (βBs) is greater than 60°. The counter track joint according to any one of claims 1 to 10, characterized in that.

12. The first outer ball track (22A) has a first outer undercut (HA) on the opening side, and the second outer ball track (22B) has a second outer undercut (HB) on the opening side. The second outer undercut (HB) is larger than the first outer undercut (HA), particularly larger than 5 times and smaller than 10 times the first outer undercut (HA). The counter track joint according to any one of claims 1 to 11, characterized in that.

13. The first outer ball track (22A) and the second outer ball track (22B) form an outer ball track group, and the first inner ball track (23A) and the second inner ball track (23B) form an inner ball track group. At least one of the outer ball track group and the inner ball track group is finished by deformation processing before curing, that is, it is not mechanically processed after curing. The counter track joint according to any one of claims 1 to 12, characterized in that.

14. One of the outer ball track group and the inner ball track group is cured and hardened, and in particular, it is finished by cutting after curing. The counter track joint according to claim 13, characterized in that.

15. The first outer ball track (22A) and the second outer ball track (22B) of the joint outer portion (12) are soft-finished and cured. The first inner ball track (23A) and the second inner ball track (23B) of the joint inner portion (11) are cured and hard-finished. The counter track joint according to any one of claims 1 to 14, characterized in that.

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