Counter track joint and side shaft

Abstract

The present invention relates to a counter track joint, comprising a joint outer part (12) and a joint inner part (13), in which in the straightened counter track joint a first pair of tracks (22A, 23A) extends towards an opening side of the joint outer part (12) and in which in the straightened counter track joint a second pair of tracks (22B, 23B) extends towards a connecting side of the joint outer part (12), the counter track joint further comprising one ball (14A, 14B) in each of the first and second pair of tracks and a ball retainer (15) with circumferentially distributed retainer windows (18) each accommodating one ball (14), the ball retainer (15) having a non-circular shape with at least three maxima and three minima when viewed in cross section.

Description

Technical Field

[0001] The present invention relates to a constant velocity joint in the form of a counter track joint and a side shaft equipped with such a counter track joint.

[0002] From German Patent Application Publication No. 10060120, a counter track joint is known that has an outer joint part, an inner joint part, balls for transmitting torque accommodated in a track pair consisting of an outer track and an inner track respectively, and a ball retainer with a retainer window in which the balls are held inside. The first outer track forms a first track pair together with the first inner track, 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 forms a second track pair together with the second inner track, 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 part and the inner joint part are axially slidable relative to each other. From International Publication No. 2013 / 029655, another counter track joint is known.

[0003] A counter track joint known from German Patent Application Publication No. 10209933 includes an inner hub having first and second inner rolling grooves, an outer hub having first and second outer rolling grooves, and a ring-shaped retainer disposed between the inner hub and the outer hub and having a radial window in which balls engaging the rolling grooves are guided inside. The outer hub of the counter track joint is an integral closed ring, and the outer rolling grooves are formed in this ring by non-cutting machining.

[0004] From European Patent Application Publication No. 2180202, a ball cage for a sliding constant velocity joint is known. This ball cage includes windows circumferentially distributed for accommodating balls, an outer spherical control surface, and an outer conical relief surface that is not mechanically machined starting from a preformed material.

[0005] From French Patent Invention No. 1287546, a sliding constant velocity joint is known that includes an outer joint portion, an inner joint portion movable longitudinally relative to this outer joint portion, a cage, and four balls for transmitting torque held within cage windows. The outer joint portion has a cylindrical inner surface with four outer tracks extending at right angles to the axis. The inner joint portion has a double conical outer surface with four inner tracks extending symmetrically to the outer tracks. The cage has a double conical outer surface in longitudinal section and a cylindrical inner surface with four notches extending longitudinally in cross section, and within these notches, during sliding movement, the web region of the inner joint portion located between the inner tracks extends.

[0006] From U.S. Patent No. 6224490, a constant velocity joint is known that includes an outer joint portion, an inner joint portion, balls for transmitting torque, and a cage. The outer joint portion has a spherical inner surface with rolling grooves. The inner joint portion has a spherical outer surface with rolling grooves, and the number of rolling grooves is equal to the number of rolling grooves provided in the outer joint portion. The rolling grooves provided in the outer joint portion and the entry slopes provided in the outer joint portion are manufactured by a plastic working method.

[0007] The problem underlying the present invention is to propose a constant velocity joint in the form of a counter track joint that can be manufactured simply and efficiently and has only slight noise emissions. Further, there is also the problem of proposing an efficient and low-noise side shaft equipped with such a counter track joint.

[0008] The constant velocity joint in the form of a counter track joint proposed by the present invention includes a longitudinal axis, a connection side and an opening side, an inner surface that is at least partially curved in the longitudinal direction, and a first outer ball track and a second outer ball track that are circumferentially distributed and arranged. It also includes a joint outer portion, a longitudinal axis, a first inner ball track and a second inner ball track of a joint inner portion, wherein the first inner ball track and the second inner ball track are circumferentially distributed and arranged on the outer surface of the joint inner portion. The first outer ball track and the first inner ball track form a first track pair that expands toward the opening side of the joint outer portion, and the second outer ball track and the second inner ball track form a second track pair that expands toward the connection side of the joint outer portion. The constant velocity joint further includes one ball for transmitting torque in each first track pair and each second track pair, and a ball retainer disposed between the joint outer portion and the joint inner portion, having an inner surface of the retainer, an outer surface of the retainer, and circumferentially distributed retainer windows each accommodating at least one ball for transmitting torque. The ball retainer has a ring web on the opening side and a ring web on the connection side adjacent to the side of the circumferentially distributed retainer windows. When the longitudinal axis of the joint inner portion and the longitudinal axis of the joint outer portion are coaxially oriented, the balls are held by the ball retainer in one radial plane, including the ball retainer. When the longitudinal axis of the joint outer portion and the longitudinal axis of the joint inner portion are aligned with each other, an outer radial gap is formed between the outer surface of the retainer and the inner surface of the joint outer portion, and an inner radial gap is formed between the inner surface of the retainer and the outer surface of the joint inner portion. The joint inner portion is axially limitedly movable relative to the joint outer portion, and the ring web on the opening side of the ball retainer can be axially supported on the support surface on the opening side of the joint outer portion and / or the joint inner portion. The ring web on the connection side isIt can be supported in the axial direction on the support surface on the connection side of the outer joint part and / or the inner joint part. At least one of the outer surface and the inner surface of the cage of the ball cage is soft-finished and hardened. The ball cage has a non-circular shape in cross-section, with a polygonal peripheral contour of the ring web on the connection side and a polygonal peripheral contour of the ring web on the opening side. Each of the polygonal peripheral contours has at least three maximum values, three minimum values, and a maximum peak-to-valley value of at least 30 micrometers.

[0009] The counter track joint has the advantage that, based on its non-circular shape, the ball cage only makes point contact with the outer joint part or the inner joint part at the axial stopper and has a predetermined spring function. This reduces noise generation at the stopper and, based on the point contact over the entire circumference, results in a smaller frictional force compared to planar contact. Another advantage is that the ball cage can be manufactured simply and inexpensively based on the surface that is finished before hardening. As a result, overall, a counter track joint that can be manufactured simply and efficiently, and in particular has little noise generation during load fluctuations, can be obtained.

[0010] The polygonal peripheral contour of the ball cage may be formed on the outer surface and / or the inner surface. In this case, the characteristics of the polygonal peripheral contour related to the present disclosure are that, in the cross-section or conical section of the ball cage, there is a peripheral line having a variable radius over the entire circumference with respect to the center point of the peripheral line, resulting in a substantially wavy extension. In this regard, the peripheral line may also be called a continuous wave. In this case, the maximum peak-to-valley value represents the difference between the minimum radius and the maximum radius of the polygonal peripheral line centered on the center point. The aforementioned peak-to-valley value relates to the peripheral lines of both ring webs, particularly on the inner and outer sides, such that point contact with a light spring action and reduced noise generation occurs at the two axial end stoppers.

[0011] There are multiple possibilities for calculating the size of the geometric shape of the peripheral line of the ball retainer. For example, the circumcircle and incircle of the wavy peripheral line can be defined, and based on this, a radial difference can be formed. The circumcircle is the smallest circle that completely encloses the peripheral line or all the measurement points along the peripheral line. This circumcircle is also called the "minimum circumscribed circle" (MCC). The incircle represents the largest circle that is completely located inside the peripheral line or all the measurement points of the peripheral line. This incircle is also called the "maximum inscribed circle" (MIC). When using this method, it is desirable that the radial interval between the circumcircle and the incircle is greater than 30 micrometers over the entire circumference. Alternatively or additionally, the peak-valley value of the peripheral line of the polygon may be determined by the minimum circle method, also called the "minimum zone circle" (MZC). In this case, two circles with the same center point are calculated, whereby one circle is located minimally outside the peripheral line or all the measurement points of the peripheral line, and the other circle is located maximally inside the peripheral line or all the measurement points of the peripheral line. When using this method, it is desirable that the radial interval between the two coaxial circles is greater than 30 micrometers over the entire circumference. Alternatively or additionally, the peak-valley value of the peripheral line of the polygon may be determined based on the Gaussian circle, also called the "least squares circle" (LSC). The Gaussian circle is determined such that the Gaussian circle is located as close as possible to the peripheral line of the polygon or all the measurement points of the peripheral line. When using this method, it is desirable that the radial intervals of the absolute maximum and absolute minimum values of the peripheral line of the polygon or the measurement points of the peripheral line with respect to the Gaussian reference circle are each greater than 15 micrometers. It is obvious that any of the above-mentioned methods can be used to calculate the peak-valley value according to the present invention. The number of measurement points used to define the peripheral line corresponds to the number of retainer windows in the area of the retainer window and is at least 6, preferably 8 or 10 or more. In the area of the ring web, the number of measurement points may be significantly higher than this, for example at least 16, or it may be a continuous measurement line.

[0012] The ball retainer has a polygonal peripheral contour on both ring webs. In this case, the inner and / or outer contour of the polygon may include at least six maxima and six minima, in particular at least eight maxima and at least eight minima.

[0013] In the region of the ring web, the inner contour of the polygon may be larger than the outer contour of the polygon by particularly at least 10 micrometers. For example, the inner contour of the polygon may have a maximum peak-to-valley value of at least 30 micrometers, and the outer contour of the polygon may have a maximum peak-to-valley value of at least 50 micrometers. With a larger peak-to-valley value or amplitude, there may be a smaller point contact in the abutment with the outer joint part and / or the inner joint part, and a greater spring action of the retainer. Preferably, the maximum peak-to-valley value of the inner and / or outer contour of the polygon is less than 200 micrometers, in particular less than 150 micrometers. The ball retainer may have an inner polygonal surface and an outer polygonal surface. In this case, the continuous waves of the outer polygon and the inner polygon may be in phase in the circumferential direction or may be phase-shifted.

[0014] The ball retainer may have a variable wall thickness over the entire circumference in the circumferential cross-section of the ring web. In this case, the difference in thickness between the minimum radial thickness and the maximum radial thickness of the ring web is preferably at least 50 micrometers.

[0015] In one embodiment, the outer surface, inner surface, and optionally at least one end face of the ball retainer may be soft-finished and may be hardened. In the context of the present disclosure, soft-finishing means, in particular, that the desired component geometry is created solely by soft machining, i.e., it is carried out and completed before hardening. After hardening, post-processing, in particular machining, that changes the geometry of at least a part of the outer surface of the ball retainer is not envisaged. The outer surface, inner surface, and / or end face of the ball retainer may be finished, in particular by deformation processes, such as forging, hot forming, cold forming, embossing, and / or hammering. Alternatively or additionally, partial surfaces of the ball retainer may be machined in a cutting manner, for example, by milling operations, turning operations, and / or grinding operations, at least in intermediate steps.

[0016] In particular, after hardening, the side surfaces of the cage window, which are located on opposite sides in the axial direction, may be further hardened. In this case, in the context of the present disclosure, being hardened and being further hardened means, in particular, that each workpiece surface before hardening is pre-manufactured with a corresponding excess dimension and is finished to the desired final geometry after hardening. The pre-manufacturing may be carried out by a cutting manufacturing method, such as turning or milling, and / or by a non-cutting manufacturing method, such as deformation processing, forging, or embossing. The finishing may be carried out, in particular, in a cutting manner, for example, by grinding or milling. During finishing, the excess dimension material, which may be, for example, a few tenths of a millimeter, of the corresponding surface provided on the intermediate product is removed after hardening.

[0017] The mutually facing surfaces of the joint outer part, the cage, and the joint inner part can, in principle, be freely selected according to requirements. For example, one, a plurality, or all of the inner surface of the joint outer part, the outer surface of the cage, the inner surface of the cage, and the outer surface of the joint inner part may be formed in a spherical shape. Alternatively or additionally, the said surfaces may have cylindrical, toroidal, and / or conical portions. When using a ball cage with spherical outer and inner surfaces, these spherical surfaces may be coaxially arranged with each other, i.e., the center points of both surfaces coincide. In one alternative possibility, the spherical surfaces may be offset from each other in the axial direction, i.e., the center points of both the inner spherical cage surface and the outer spherical cage surface have an axial distance (offset) from each other. The same applies similarly to these when the spherical inner surface of the outer part and / or the spherical outer surface of the inner part are used.

[0018] In one embodiment, in a state where the ball retainer is centered and arranged with respect to the outer joint portion and the inner joint portion, at least one of the outer radial gap and the inner radial gap may be larger than 75 micrometers. The inner radial gap and the outer radial gap may have different sizes, and in particular, they may differ from each other by at least 25 micrometers. Similarly, the outer total axial play formed between the outer surface of the retainer and the inner surface of the outer joint portion and the inner total axial play formed between the inner surface of the retainer and the outer surface of the inner joint portion may have different sizes. For example, the outer total axial play may be larger than the inner total axial play by at least 10% and / or at least 100 micrometers, and in particular, by at least 20% and / or at least 200 micrometers. Further, when the joint component positions the inner joint portion axially in the middle with respect to the ball retainer in a torque load state, the outer total axial play may be formed so as to be asymmetrically divided into the axial play on the outer opening side and the axial play on the outer connection side. In this case, the axial play on the connection side is preferably smaller than the axial play on the opening side. Thereby, when press-fitting the shaft through the ball retainer without the ball getting caught in the ball track or being crimped to the ball track, it is advantageously supported that the inner joint portion can be supported on the support surface of the outer joint portion in the axial direction. The different configurations of the radial play or the axial play contribute to simple and inexpensive manufacturing. This is because a rough play is possible on one of the four pairs of surfaces.

[0019] The outer and inner ball tracks may each be curved, at least in the central section, when viewed in the longitudinal section of the track bottom. The first and second outer ball tracks may form an outer ball track group, and the first and second inner ball tracks may form a second ball track group. In this case, in one configuration, one of the outer ball track group and the inner ball track group is hardened and hard machined, and the other of the outer ball track group and the inner ball track group is finished before hardening, that is, not mechanically machined after hardening or no post-processing is performed to change the geometry. The latter ball track group can be finished before hardening, for example, by non-cutting machining. After hardening, shot peening may be further performed for surface modification. The ball track group finished before hardening contributes to low-cost manufacturing. At the same time, based on the ball track group hardened and then hard finished, the support surface of the joint outer part, and the counter track shape, a good guiding function and supporting function for the ball retainer and thus high efficiency are provided. When the outer ball track group is soft finished, the outer radial gap or the outer total axial play is preferably larger than the inner radial gap or the inner total axial play. When the inner ball track group is soft finished, the outer radial gap or the outer total axial play is preferably smaller than the inner radial gap or the inner total axial play.

[0020] For example, a ball track hard machined by grinding or turning can have a smaller surface roughness than a ball track that is soft finished, that is, not machined after hardening. The latter may optionally have a fine structure produced by shot peening performed before hardening.

[0021] The first outer ball track and the second outer ball track are preferably each formed such that, when viewed in cross-section, two-point contact with an associated ball for transmitting torque is formed. Alternatively or additionally, the first inner ball track and the second inner ball track may also each be formed such that, when viewed in cross-section, two-point contact with an associated ball for transmitting torque is formed. The two-point contact may be produced, for example, by a Gothic or elliptical track shape when viewed in cross-section. The two-point contact or two-point track enables self-centering measurement of the ball track. However, basically a circular track may also be used.

[0022] Basically, two embodiments are possible which result from arranging ball tracks finished before or after hardening corresponding to the outer joint part or the inner joint part. In a first configuration, a ball track finished with a soft finish before hardening may be arranged corresponding to the outer joint part, while the ball track finished hard after hardening is arranged corresponding to the inner joint part. In an alternative reverse configuration, a ball track finished with a soft finish before hardening may be arranged corresponding to the inner joint part, while the ball track finished hard after hardening is arranged corresponding to the outer joint part.

[0023] In one example, the inner surface of the outer part is hardened and may not be machined mechanically after hardening. That is, the geometric shape of the inner surface is finished or complete before hardening. After hardening, post-processing, in particular machining, for changing the geometric shape of the inner surface is not envisaged. The inner surface of the outer part may be finished, in particular by deformation processing, for example by forging, hot forming, embossing and / or hammering. Alternatively or additionally, the inner surface of the outer part may be machined in a cutting manner, at least in an intermediate step, for example by milling operations, turning operations and / or grinding operations.

[0024] The outer surface of the inner part of the joint may be hardened and may be machined hard after hardening. This particularly means that the outer surface of the inner part before hardening is pre-manufactured with a corresponding excess dimension and is finished to the desired final geometry after hardening. In this case, the pre-manufacturing may be carried out by a cutting manufacturing method such as turning or milling, and / or by a non-cutting manufacturing method such as deformation processing or forging. The finishing of the outer surface may be carried out particularly in a cutting manner, for example by grinding or turning.

[0025] The first outer ball track may form a first undercut towards the opening side, and the second outer ball track may form a second undercut towards the opening side. In this case, in particular, it is assumed that 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.

[0026] The above-described embodiment relates to an embodiment in which the geometry of the ball track of the outer part of the joint is manufactured exclusively by soft machining, and the ball track of the inner part of the joint is hard machined. It is obvious that in an alternative embodiment in which the ball track of the outer part of the joint is hard machined and the geometry of the ball track of the inner part of the joint is manufactured exclusively by soft machining only before hardening, each feature must be correspondingly reversed.

[0027] In one embodiment, the outer joint portion and the inner joint portion may be formed such that the inner joint portion is angularly movable relative to the outer joint portion by a bending angle (β) greater than 20°, particularly greater than 30°. The first ball of the first track pair forms a first partial circular diameter, and the second ball of the second track pair forms a second partial circular diameter. The ratio of at least one of the first and second partial circular diameters (PCDA, PCDB) to the maximum partial circular diameter (PCDS) of the insertion opening of the inner joint portion is preferably less than 2.5, particularly less than 2.1 (PCDA / PCDS < 2.5 and / or PCDB / PCDS < 2.5).

[0028] The number of balls for transmitting torque and the corresponding outer and inner ball tracks can preferably be divided by 2, particularly 8, but other numbers such as 6 or 10 are also possible.

[0029] The above problem is further solved by a side shaft for transmitting torque from a transmission to a vehicle wheel, particularly for rear-wheel driving an automobile, the side shaft including a constant velocity joint on the transmission side, a constant velocity joint on the wheel side, and a shaft located therebetween, wherein at least one of the constant velocity joint on the transmission side and the constant velocity joint on the wheel side is a counter track joint configured based on one of the above embodiments. By the side shaft provided with the counter track joint according to the present invention, advantageously, particularly a small noise during load variation can be obtained.

[0030] Preferred embodiments will be described below with reference to the drawings.

Brief Description of the Drawings

[0031]

Figure 1A

Figure 1B

Figure 1C

Figure 1D

Figure 1E

Figure 1F

Figure 2A

Figure 2B

Figure 2C

Figure 2D

Figure 3A

Figure 3B

Figure 3C

Figure 4

Figure 5A

Figure 5B

Figure 5C

Figure 6

Figure 7

[0032] Figures 1A to 6, which will be described together below, show a counter track joint 11 according to the present invention. The counter track joint 11 includes a joint outer portion 12, a joint inner portion 13, a plurality of balls 14A, 14B for transmitting torque, and a ball retainer 15. A circumferentially extending gap 25 is formed between a substantially spherical outer surface 16 of the ball retainer 15 and a substantially spherical inner surface 24 of the joint outer portion 12. Also, a circumferentially extending gap 27 is formed between a substantially spherical inner surface 17 of the ball retainer 15 and a substantially spherical outer surface 26 of the joint inner portion 13. In the present embodiment, the surface center points M16 and M17 are located in one common joint center plane EM, and in another configuration, the surface center points M16 and M17 may each 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 in retainer windows 18 distributed circumferentially within one plane in the ball retainer 15. 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 intersections of the longitudinal axes L12, L13 and the joint center plane EM that occur during torque loading form the joint center point M.

[0033] In the embodiment shown here, the inner surface 24 of the joint outer portion 12, the retainer outer surface 16, the retainer inner surface 17, and the outer surface 26 of the joint inner portion 13 are formed substantially spherically. Alternatively or additionally, one or more of the said surfaces may have cylindrical, toroidal and / or conical portions. With respect to the inner surface 24 of the outer portion 12, in Figure 1A, an opening-side section 24a, a central section 24c, and a bottom-side section 24b are marked. The bottom-side section 24b forms a support surface on which the ball retainer 15 can be supported axially with its outer surface 16. Further, on the outer surface 26 of the joint inner portion 13, an opening-side section 26a, a central section 26c, and a bottom-side section 26b are marked.

[0034] The outer joint portion 12 has, for example, a bottom 19 that can transition to a connection pin and an opening 20. The inner joint portion 13 has an opening 21 into which a pin of a drive shaft 30 that transmits torque can be inserted non-rotatably relative to each other. The counter track joint 11 to which the shaft 30 is attached is shown in FIGS. 2A to 2D. The position of the bottom 19 is hereinafter referred to as the axial direction "towards the connection side", and the position of the opening 20 is hereinafter referred to as the axial direction "towards the opening side". These terms are also used with respect to the inner joint portion, and in this case, the actual connection of the shaft to the inner joint portion 13 remains unconsidered. It is self-evident that the outer joint portion may be configured to open towards the connection side, for example, in the form of a disk joint, instead of having a bottom.

[0035] Over the entire circumference, a first track pair 22A, 23A provided with a first ball 14A for transmitting torque and a second track pair 22B, 23B provided with a second ball 14B for transmitting torque are alternately provided. The shape of the first track pair 22A, 23A is shown in FIG. 1B, and the shape of the second track pair 22B, 23B is shown in FIG. 1C. 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 respectively, while the center point of the second ball 14B defines a second center point line respectively when moving along the outer second ball track 22B and the inner second ball track 23B.

[0036] 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 bottom of the ball track, but the contact does not necessarily have to occur. In the illustrated extended position, 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 positions of the joint that is slightly bent by up to 2°.

[0037] The first and second track pairs are each located in one radial plane passing through the joint with their center lines. The balls 14A, 14B are each accommodated in a cage window 18 provided in the ball cage 15. The radial planes have equal angular distances from each other. The number of balls 14A, 14B for transmitting torque and the number of corresponding outer and inner ball tracks are 8 in this case, but are not limited thereto. In this case, the two first track pairs 22A, 23A of the joint outer portion 12 and the joint inner portion 13 are located opposite each other in the diametrical direction, and the two second track pairs 22B, 23B are located opposite each other in the diametrical direction.

[0038] Next, the features of the counter track joint 11 according to the present invention, particularly the configuration of the ball cage 15, will be described in more detail. In this case, the following definitions apply in relation to the counter track joint according to the present invention.

[0039] The joint bending angle β defines the angle formed between the longitudinal axis L12 of the outer joint portion 12 and the longitudinal axis L13 of the inner joint portion 13. The joint bending angle β is zero in a straight joint.

[0040] The track bending angle β / 2 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 / 2 is always half of the joint bending angle β at any angular position of the joint.

[0041] The opening release 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.

[0042] The control angle δ / 2 defines the angle formed by the tangent contacting each ball center point line at the ball center point with the longitudinal axis L belonging to the outer joint portion or the inner joint portion in a straight joint. The control angle δ / 2 corresponds to half of the opening release angle δ.

[0043] The center point plane EM is defined by the ball center points of the balls 14A, 14B that transmit torque in a straight joint.

[0044] The first partial circle diameter PCDA defines the diameter formed by the center points of a plurality of first balls 14A in a straight joint.

[0045] The second partial circle diameter PCDB defines the diameter formed by the center points of a plurality of second balls 14B in a straight joint.

[0046] The partial 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.

[0047] The ball cage 15 has a ring web 37 on the opening side and a ring web 38 on the connection side, which are adjacent to the side of the cage window 18 distributed in the circumferential direction. Based on the ring gap 25, the ball cage 15 is movably limited in the axial direction relative to the joint outer part 12. Thereby, the vibration generated during operation between the joint inner part 13 and the joint outer part can be compensated. The axial movement in the direction of the opening 20 is restricted by the stopper S20 on the opening side. For this purpose, as shown in Fig. 1E, the ring web 37 on the opening side of the ball cage 15 abuts against the support surface 26a on the opening side of the joint inner part 13 and / or the support surface 24a on the opening side of the joint outer part 12. The axial movement in the direction of the bottom is restricted by the stopper S19 on the bottom side. For this purpose, as shown in Fig. 1F, the ring web 38 on the connection side of the ball cage abuts against the support surface 26b on the connection side of the joint inner part 13 and / or the support surface 24b on the opening side of the joint outer part 12.

[0048] In the present invention, at least one of the outer surface 16 and the inner surface 17 of the ball cage is subjected to soft finishing and hardened. Further, the ball cage 15 has a non-circular or polygonal shape when viewed in cross-section. In particular, as can be seen from Figs. 4, 5B and 5C, the ball cage has polygonal peripheral contours K37, K38, K39 in the regions of the intermediate web 39 and the ring webs 37, 38. The peripheral contours K37, K38, K39 each have at least three maximum values PH, sometimes called high points, at least three minimum values PL, sometimes called low points, and maximum peak-to-valley values HL, HLo, HLi of at least 30 micrometers. The group of maximum values may include at least one absolute maximum value and a plurality of relative maximum values. The group of minimum values may include at least one absolute minimum value and a plurality of relative minimum values.

[0049] Based on the shape of the polygon, the ball cage 15 initially contacts the joint outer part 12 or the joint inner part 13 only at a plurality of points, i.e., only in the region of the maximum value PH, at least initially, in the axial stoppers S19, S20. Due to the point contact of the polygon-shaped cage and the slight spring action, the annular stopper is "soft", and correspondingly, the noise generation is relatively small.

[0050] The polygonal peripheral contours K37, K38, K39 of the ball cage 15 each have a variable radius R over the entire circumference with respect to the peripheral line center points MK, MC, MG, MI, thereby resulting in a wavy extension. In this case, the maximum peak-valley values HL, HLo, HLi represent the difference between the minimum radius RL and the maximum radius RH of the peripheral line of the polygon centered on the center point. The circle with the maximum radius RH may also be called the maximum circle line, and the circle with the minimum radius may also be called the minimum circle line. The maximum circle line and the minimum circle line may be concentric or may be slightly offset from each other.

[0051] To calculate the size of the geometric shape of the peripheral line of the polygon, which is also generally labeled with the symbol K, there are a plurality of possibilities, which are exemplified below.

[0052] For example, the peak-valley value HL of the peripheral line K of the polygon can also be determined based on the Gaussian circle LSC, which is also called the "least squares circle". As exemplarily shown in FIG. 4, the Gaussian circle LSC is determined such that the Gaussian circle LSC is located as close as possible to the peripheral line of the polygon of the peripheral line K or all the measurement points pm. When using this method, in the present invention, it is assumed that the radial distance sh of the absolute maximum value PH and the radial distance sl of the absolute minimum value PL from the peripheral line K of the polygon or the measurement points pm of the peripheral line to the Gaussian reference circle LSC are each greater than 15 micrometers. From this, it can be seen that the peak-valley value HL, which forms the radial difference between the absolute minimum value PL and the absolute maximum value PH, is greater than 30 micrometers, and particularly greater than 50 micrometers.

[0053] Another method for determining the peak-valley value HL of the peripheral line K of a polygon is the minimum circle method, also referred to as the "minimum circumscribed circle" (MZC), which will be described below based on FIG. 5B. The peripheral line K37o outside the ring web 37 of the ball retainer 15 measured in the measurement plane E37 shown in FIG. 5A is shown. In the minimum circle method, two circles CH and CL having the same center point MC are calculated. Thereby, one circle CH is positioned minimally outside the peripheral line K or all the measurement points pm of the peripheral line K, and the other circle CL is positioned maximally inside the peripheral line K or all the measurement points pm of the peripheral line K. When using this method, the radial distance HL between the two coaxial circles CH and CL, represented by HLo in FIG. 5B, is desirably greater than 30 micrometers, particularly greater than 50 micrometers.

[0054] In one exemplary alternative or supplementary method, which will be described based on FIG. 5C, the circumscribed circle MCC and the inscribed circle MIC of the waveform's peripheral line K are determined, based on which the radial difference HL can be formed. The peripheral line K37i outside the ring web 37 of the ball retainer 15 measured in the measurement plane E37 shown in FIG. 5A is shown. The circumscribed circle MCC is the smallest circle that completely surrounds the peripheral line K37i or all the measurement points pm along the peripheral line. This circumscribed circle has the center point MC and is also referred to as the "minimum circumscribed circle". The inscribed circle MIC represents the largest circle that is completely located inside all the measurement points pm of the peripheral line K or the peripheral line. This inscribed circle has the center point MI and is also referred to as the "maximum inscribed circle" (MIC). In the present invention, it is assumed that the radial distance or peak-valley value HL between the circumscribed circle MCC and the inscribed circle MIC, represented by HLi in FIG. 5C, is greater than 30 micrometers over the entire circumference, particularly greater than 50 micrometers, and optionally greater than 75 micrometers.

[0055] It is obvious that any of the methods described above can be used to calculate the peak - valley value HL according to the present invention. The number of measurement points used to define the peripheral line corresponds to the number of the retainer windows 18 in the area of the retainer window 18. In this example, as can be seen in FIGS. 3C and 4, it is 8. In the area of the ring webs 37, 38, the number of measurement points may be significantly more than this. For example, as shown in FIGS. 5B and 5C, it may be at least 16 or continuous measurement lines.

[0056] In the area of the ring webs 37, 38, the inner peripheral contour Ki of the polygon may be larger than the outer peripheral contour Ko of the polygon, especially by at least 10 micrometers. For example, in the ring web 37, the inner peripheral contour K37i of the polygon may have a maximum peak - valley value HL of at least 50 micrometers, and the outer peripheral contour K37o of the polygon may have a maximum peak - valley value HL of at least 30 micrometers. With a larger peak - valley value or amplitude, there will be a smaller point contact in the contact with the outer joint part 12 and / or the inner joint part 13, and a greater spring action of the retainer 15. The maximum peak - valley value HL of the inner peripheral contour Ki and / or the outer peripheral contour Ko of the polygon is preferably less than 200 micrometers, especially less than 150 micrometers.

[0057] The outer surface 16, the inner surface 17, and optionally at least one end face of the ball retainer 15 are finished with a soft finish and hardened. In other words, the desired geometric shape of the above - mentioned surfaces is produced solely by soft machining, that is, before hardening. After hardening, no post - machining, especially cutting, is assumed to change the geometric shape of at least the outer surface 16 and the inner surface 17 of the ball retainer 15. The outer surface 16 and the inner surface 17 of the ball retainer 15 may be finished by deformation machining. Alternatively or additionally, the partial surfaces of the ball retainer may be machined by cutting, at least in an intermediate step.

[0058] After hardening, the side surfaces of the cage window 18 located on opposite sides in the axial direction may be further hardened. At this time, the side surfaces are finished to the desired final geometric shape. The preliminary manufacture of the window 18 may be performed by a cutting method such as punching. The finishing may be performed particularly by a cutting method, for example, by grinding. During the finishing, the excess dimensional material, which may be, for example, several tenths of a millimeter, of the corresponding surface provided on the intermediate product is removed after hardening.

[0059] The mutually opposing surfaces of the joint outer portion 12, the cage 15, and the joint inner portion 13 can in principle be freely selected according to requirements. As can be seen particularly in FIG. 6 where the auxiliary ball Sh is illustratively drawn, the inner surface of the joint outer portion is substantially spherical. The same applies to the outer surface of the cage, the inner surface of the cage, and the outer surface of the joint inner portion. In a state where the ball cage 15 is centered and arranged with respect to the joint outer portion 12 and the joint inner portion 13, at least one of the outer radial gap 25 and the inner radial gap 27 is larger than 75 micrometers. The inner radial gap 27 and the outer radial gap 25 may have different sizes, and particularly may differ from each other by at least 25 micrometers.

[0060] The outer surface 16 of the cage of the ball cage 15, the inner surface 24 of the outer joint portion 12, and the inner surface 17 of the cage of the ball cage and the outer surface 26 of the inner joint portion 13 are such that when the counter track joint 11 is assembled and straightened, the total axial play So on the outer side between the ball cage 15 and the outer joint portion 12 and the total axial play Si on the inner side between the ball cage 15 and the inner joint portion 13 are formed to have different sizes respectively. As shown in FIG. 1D, the total axial play So on the outer side is composed of the axial play Soa on the outer opening side and the axial play Sob on the connection side between the cage 15 and the outer portion 12. Similarly, the total axial play Si on the inner side is composed of the axial play Sia on the inner opening side and the axial play Sib on the connection side between the cage 15 and the inner portion 13. In this case, the total axial play So on the outer side may be, for example, at least 10% and / or at least 100 micrometers larger than the total axial play Si on the inner side.

[0061] The spherical surfaces 24, 16, 17, 26 of the joint components 12, 13, 15 are such that in the assembled state of the joint 11 where the equator of the spherical surface 24 of the outer joint portion 12 and the equator of the outer surface 16 of the cage are located in one plane, and the equator of the inner surface 17 of the cage and the equator of the spherical surface 26 of the inner joint portion 13 are located in one plane, the outer radial gap 25 is formed to be larger in the direction of the opening side than in the direction of the connection side. Thereby, when the shaft 30 is press-fitted through the ball cage 15 or the support surfaces 26b, 24b, the balls 14A, 14B are not caught in the ball tracks 22A, 23A; 22B, 23B, and the inner joint portion 13 can be supported by the outer joint portion 12 in the axial direction. In the present embodiment, both the inner surface 17 and the outer surface 16 of the ball cage 15 are substantially coaxially arranged with each other.

[0062] The first and second outer bolt tracks 22A, 22B, which may also be collectively referred to as the outer bolt track or outer bolt track group, and the first and second inner bolt tracks 23A, 23B, which may also be collectively referred to as the inner bolt track or inner bolt track group, may be manufactured differently from each other. In this embodiment, the bolt tracks 22A, 22B of the joint outer portion 12 are soft-finished before hardening, and the bolt tracks 23A, 23B of the joint inner portion 13 are hard-finished after hardening.

[0063] The joint outer portion 12, particularly the first and second outer bolt tracks 22A, 22B, can be manufactured by a deformation processing operation, such as forging, hot deformation processing, cold deformation processing, embossing, and / or hammering. It is self-evident that a cutting intermediate step may be provided between individual deformation processing steps, for example, for internal diameter turning and / or deburring. The first outer bolt track 22A of the joint outer portion 12 has an arcuate central functional section. The center point of the arc forming the central functional portion is offset towards the opening side with respect to the central plane of the joint 11, which is also referred to as an axial offset having an offset plane EA. The first outer bolt track 22A of the joint outer portion 12 has a radially expanding portion 28 at its opening-side end, thereby facilitating the insertion of the associated ball 14A during assembly. The first outer bolt track 22A of the joint outer portion 12 has a pocket 29A recessed radially with respect to the functional track section at its bottom-side end. A ball 14Ab located diametrically opposite can penetrate into the pocket 29A when the ball 14Aa inserted from the opening side is incorporated.

[0064] The second outer bolt track 22B has an arcuate central functional section. The center point of the arc forming the central functional portion is shifted within the plane EB toward the bottom side with respect to the central plane EM of the joint 11. The second outer bolt track 22B of the outer portion 12 of the joint has, at its bottom-side end, a pocket 29B recessed radially with respect to the functional track section.

[0065] The first outer bolt track 22A forms a first undercut H22A toward the opening side, and the second outer bolt track 22B forms a second undercut H22B toward the opening side. In this case, as particularly recognized in FIG. 1D, the first undercut H22A of the first bolt track 22A opening toward the opening side is smaller than the second undercut H22B of the second bolt track 22B opening toward the connection side.

[0066] In the case of the outer portion 12 of the joint of the present embodiment, preferably, the spherical surface 24 is also finished with a soft finish, that is, the spherical surface 24 remains unmechanically processed after hardening. That is, the entire inner contour of the outer portion 12 provided with the bolt tracks 22A, 22B and the spherical surface 24 is finished before hardening. No post-processing for changing the geometric shape is assumed after hardening. In this case, the inner surface 24 of the outer portion can be manufactured by a deformation processing operation together with the first and second outer bolt tracks 22A, 22B.

[0067] The first and second outer bolt tracks 22A, 22B are particularly shaped such that, as seen in the cross-section of each bolt track, two-point contact with the associated balls 14A, 14B is formed. The two-point contact may be caused, for example, by a Gothic-style or elliptical track shape as seen in the cross-section.

[0068] The inner joint portion 13, in particular the first and second inner ball tracks 23A, 23B, can be manufactured by machining methods such as turning and / or milling. In this case, manufacturing by deformation processing operations is similarly possible. The inner ball tracks 23A, 23B may be pre-manufactured with corresponding excess dimensions before hardening. After hardening, the inner ball tracks 23A, 23B are finished to the desired final geometry. The finishing is carried out in particular in a cutting manner, for example by grinding and / or turning operations. The first and second inner ball tracks 23A, 23B are also preferably formed such that, when viewed in the cross-section of each ball track, two-point contact with the respective balls 14A, 14B is formed.

[0069] In this embodiment, preferably, the spherical outer surface 26 of the inner joint portion 13 is also first pre-machined soft, then hardened, and after hardening, it is finish-machined hard. The pre-manufacturing may be carried out by a cutting manufacturing method such as turning or milling, and / or by a non-cutting manufacturing method such as deformation processing or forging. The finishing of the outer surface 26 of the inner joint portion is carried out in particular in a cutting manner, for example by grinding.

[0070] The counter track joint 11 shown here is preferably designed such that the joint components 12, 13 can angularly move relative to each other by a bending angle β greater than 20°. In this case, the ratio of the first and / or second partial circle diameters PCDA, PCDB to the maximum partial circle diameter PCDS of the insertion opening of the inner joint portion 13 is in particular less than 2.5, that is, PCDA / PCDS < 2.5 and / or PCDB / PCDS < 2.5.

[0071] Figure 7 shows a side shaft 40 according to the present invention for transmitting torque from a transmission to a vehicle wheel (not shown). The side shaft 40 includes a constant velocity joint 42 on the transmission side, a shaft 41, and a constant velocity joint 2 on the wheel side. The constant velocity joint on the wheel side is the counter track joint according to the present invention shown in FIGS. 1A-1D. The side shaft 40 can be used particularly for rear-wheel drive of an automobile.

Explanation of Reference Numerals

[0072] 11 Counter track joint 12 Outer joint portion 13 Inner joint portion 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 23A, 23B Inner ball tracks 24 Inner surface (12) 25 Outer gap 26 Outer surface (13) 27 Inner gap 28 Radial expansion portion 29 Pocket 30 Shaft 31 Notch 32 Web (12) 33 Web (13) 34 Expansion portion 35A, 35B Chamfered portion 36 Opening 37, 38 Ring web 39 Intermediate web 40 Side shaft 41 Shaft 42 Constant velocity joint C Circle EA First offset plane The second offset plane of EB The joint center plane of EM The peak-valley value of HL The surrounding contour line of K The longitudinal axis of L The joint center point of M The measurement point of pm The circular diameter of PCD The maximum value of PH The minimum value of PL The radius of R The stoppers of S19, S20 The total axial play on the inner side of Si The total axial play on the outer side of So The tangent of T The joint bending angle of β The opening angle of δ

Claims

1. A counter track joint, comprising a longitudinal axis (L12), a connection side and an opening side, an inner surface (24) that is at least partially curved in the longitudinal direction, and a first outer ball track (22A) and a second outer ball track (22B) that are circumferentially distributed and arranged, a joint outer portion (12); a joint inner portion (13) comprising 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), the joint inner portion (13); including the first outer ball track (22A) and the first inner ball track (23A) form a first track pair (22A, 23A) 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 (22B, 23B) that expands toward the connection side of the joint outer portion (12); the counter track joint further includes one ball (14A, 14B) that transmits torque in each of the first track pairs (22A, 23A) and each of the second track pairs (22B, 23B); a ball retainer (15) disposed between the joint outer portion (12) and the joint inner portion (13), having a retainer inner surface (17), a retainer outer surface (16), and circumferentially distributed retainer windows (18) that each accommodate at least one ball (14A, 14B) that transmits torque, the ball retainer (15) having an opening-side ring web (37) and a connection-side ring web (38) adjacent to the side of the circumferentially distributed retainer windows (18), and 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) within a single radial plane (EM), the ball retainer (15); including When the longitudinal axis (L12) of the joint outer portion (12) and the longitudinal axis (L13) of the joint inner portion (13) are aligned in a straight line with each other, an outer radial gap (25) is formed between the outer surface (16) of the cage and the inner surface (24) of the joint outer portion (12), and an inner radial gap (27) is formed between the inner surface (17) of the cage and the outer surface (26) of the joint inner portion (13). The joint inner portion (13) is movable relative to the joint outer portion (12) in a limited manner in the axial direction, and the ring web (37) on the opening side of the ball cage (15) can be supported in the axial direction on the support surfaces (24a, 26a) on the opening side of at least one of the joint outer portion (12) or the joint inner portion (13), and the ring web (38) on the connection side can be supported in the axial direction on the support surfaces (24b, 26b) on the connection side of at least one of the joint outer portion (12) or the joint inner portion (13). In a counter track joint At least one of the outer surface (16) and the inner surface (17) of the cage is soft-finished and hardened. The ball cage (15) has a non-circular shape when viewed in cross-section, whereby the ring web (37) on the opening side that contacts the support surfaces (24a, 26a) on the opening side during axial sliding and the ring web (38) on the connection side that contacts the support surfaces (24b, 26b) on the connection side each have at least a polygonal peripheral contour (K) with three maximum values (PH), three minimum values (PL), and a maximum peak-valley value (HL, HLi, HLo) of at least 30 micrometers. A counter track joint, characterized in that.

2. The counter track joint according to claim 1, wherein the maximum peak-valley value (HL) of the polygonal peripheral contour (K) is less than 200 micrometers.

3. The peripheral contour (K) of the polygon includes an inner peripheral contour (K37i) and an outer peripheral contour (K37o), and the maximum peak-valley value (HLi) of the inner peripheral contour (K37i) is at least 10 micrometers greater than the maximum peak-valley value (HLo) of the outer peripheral contour (K37o). The counter-track joint according to claim 1 or 2.

4. The ball retainer (15) has a variable wall thickness over the entire circumference in the cross section of the ring webs (37, 38), and the difference in thickness between the minimum radial thickness and the maximum radial thickness is at least 50 micrometers. The counter-track joint according to any one of claims 1 to 3.

5. The peripheral contour (K) of the polygon has at least six maximum values (PH) and six minimum values (PL). The counter-track joint according to any one of claims 1 to 4.

6. In a state where the ball retainer (15) is centered and arranged with respect to the outer joint portion (12) and the inner joint portion (13), at least one of the outer radial gap (25) and the inner radial gap (27) is greater than 75 micrometers, and the other of the outer radial gap (25) and the inner radial gap (27) is greater than 50 micrometers. The counter-track joint according to any one of claims 1 to 5.

7. In the unloaded state, the outer total axial play (So) formed between the outer surface (16) of the retainer and the inner surface (24) of the outer joint portion (12), and the inner total axial play (Si) formed between the inner surface (17) of the retainer and the outer surface (26) of the inner joint portion (13) have different sizes, and the outer total axial play (So) is at least 10% greater than the inner total axial play (Si). Regarding the total axial play (Si) inside in the torque load state, when the inner joint portion (13) is positioned axially intermediate with respect to the ball retainer (15), the outer total axial play (So) is asymmetrically divided into an axial play (Soa) on the outer opening side and an axial play (Sob) on the outer connection side, of the counter track joint according to any one of claims 1 to 6.

8. 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. One of the outer ball track group and the inner ball track group is hardened and hard machined, and the other of the outer ball track group and the inner ball track group is finish machined before hardening, that is, not mechanically machined after hardening. The other of the outer ball track group and the inner ball track group is finish machined by non-cutting type machining and forming, of the counter track joint according to any one of claims 1 to 7.

9. The first outer ball track (22A) has a first outer undercut (H22A) on the opening side, the second outer ball track (22B) has a second outer undercut (H22B) on the opening side, and the first outer undercut (H22A) is smaller than the second outer undercut (H22B), of the counter track joint according to any one of claims 1 to 8.

10. The inner surface (24) of the joint outer portion (12), the first outer ball track (22A), and the second outer ball track (22B) are soft finish machined and hardened, and the first inner ball track (23A) and the second inner ball track (23B) of the joint inner portion (13) are hardened and hard finish machined, of the counter track joint according to any one of claims 1 to 9.

11. The first outer bolt track (22A) of the joint outer portion (12) and the second outer bolt track (22B) are hardened and subjected to a hard finish after hardening, and the first inner bolt track (23A) of the joint inner portion (13) and the second inner bolt track (23B) are subjected to a soft finish and hardened. The counter track joint according to any one of claims 1 to 10.

12. The first outer bolt track (22A) and the second outer bolt track (22B) are each formed so as to form two-point contact with the respective attached balls (14A, 14B) for transmitting torque when viewed in cross section, and the first inner bolt track (23A) and the second inner bolt track (23B) are each formed so as to form two-point contact with the respective attached balls (14A, 14B) for transmitting torque when viewed in cross section. The counter track joint according to any one of claims 1 to 11.

13. The joint outer portion (12) and the joint inner portion (13) are formed so that the joint inner portion (13) can be angularly movable by a bending angle (β) greater than 20° relative to the joint outer portion (12). The counter track joint according to any one of claims 1 to 12.

14. A side shaft for transmitting torque from a transmission to a vehicle wheel, the side shaft including a constant velocity joint on the transmission side, a constant velocity joint on the wheel side, and a shaft positioned therebetween. In the side shaft, at least one of the constant velocity joint on the transmission side and the constant velocity joint on the wheel side is a counter track joint according to any one of claims 1 to 13. A side shaft characterized by that.

Images