Reverse track universal joint and method for manufacturing a reverse track universal joint

Abstract

The present invention relates to a reverse track universal joint, which comprises: a universal joint outer member (12), a universal joint inner member (13), wherein, a first track pair (22A, 23A) expands towards the opening side of the universal joint outer member (12) when the reverse track universal joint is stretched, and a second track pair (22B, 23B) expands towards the connection side of the universal joint outer member (12) when the reverse track universal joint is stretched; one ball (14A, 14B) in each of the first and second track pairs; a ball cage (15) with cage windows (18) distributed in a circumferential manner, and each cage window accommodates one of the balls (14), wherein, one of the external ball track group and the internal ball track group is hardened and machined by hard cutting, and the other of the external ball track group and the internal ball track group is soft machined and then hardened. The present invention also relates to a method for manufacturing a reverse track universal joint (11).

Description

Field of the Invention

[0001] The present invention relates to a constant velocity universal joint in the form of a reverse track universal joint and a method for manufacturing a reverse track universal joint. Background Art

[0002] It is known from DE 100 60 120 A1: A reverse track universal joint having a universal joint outer member with a curved outer track, a universal joint inner member with a curved inner track, balls for transmitting torque received in a track pair formed by the outer track and the inner track; and a ball cage with cage windows in which the balls are held in a common plane. The first outer track and the first inner track form a first track pair, the first control angle of the first track pair opens towards a first axis, 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 opens towards a second axis and a second ball is held in the second track pair. The universal joint outer member and the universal joint inner member can move axially relative to each other.

[0003] It is known from WO 2013 / 029655 A1 a reverse track universal joint. The first track pair opens towards the open side when the universal joint is stretched, and the second track pair opens towards the connection side. The control angle of the first track pair is greater than the control angle of the second track pair. The center line of the first track pair of the universal joint outer member extends radially within a reference arc in the direction of the connection side and extends radially outside the reference arc in the direction of the open side.

[0004] It is known from DE 102 09 933 A1 a reverse track universal joint, comprising: an inner hub with a first inner raceway and a second inner raceway; an outer hub with a first outer raceway and a second outer raceway, the first and second outer raceways and the first and second inner raceways respectively form a pair; an annular cage, the cage is arranged between the inner hub and the outer hub and has radial windows, and the balls fitted into the raceways are guided in the windows. The outer hub of the reverse track universal joint is an integral closed ring, and the outer raceways are formed into the ring without cutting.

[0005] It is known from US 6 224 490 B1 a constant velocity universal joint with a universal joint outer member, a universal joint inner member, balls for transmitting torque and a cage. The universal joint outer member has a grooved spherical inner surface. The universal joint inner member has a grooved spherical outer surface, and the number of grooves in the universal joint inner member is equal to the number of grooves in the universal joint outer member. The grooves in the universal joint outer member and the slip-in chamfers at the universal joint outer member are manufactured by a plastic working method.

[0006] A universal joint inner part for a constant velocity joint is known from DE 10 2005 063 006 A1. The universal joint inner part has an outer spherical guiding surface for guiding a ball cage and a plurality of circumferentially distributed ball tracks formed in the spherical guiding surface for receiving torque-transmitting balls. Each ball track has a first track section machined hard for guiding the balls and a second track section that is not machined mechanically and that does not assume a guiding function for the balls. SUMMARY OF THE INVENTION

[0007] The object of the present invention is to provide a constant velocity joint that is cost-effective, has high efficiency and a long service life and is particularly also suitable for large bending angles. The object also lies in providing a method for manufacturing a corresponding reverse track constant velocity joint.

[0008] According to the invention, there is provided a constant velocity joint in the form of a reverse track constant velocity joint, comprising: a joint outer part having a longitudinal axis, a connection side and an open side, and a first outer ball track and a second outer ball track, the first outer ball track and the second outer ball track being arranged circumferentially in the inner surface of the joint outer part and forming a first group of ball tracks; a joint inner part having a longitudinal axis and a first inner ball track and a second inner ball track, the inner ball tracks being arranged circumferentially in the outer surface of the joint inner part and forming an inner group of ball tracks; wherein the first outer ball track and the first inner ball track form a first track pair with each other, the first track pair being at least partially curved and extending towards the open side of the joint outer part, and wherein the second outer ball track and the second inner ball track form a second track pair with each other, which are at least partially curved and extend towards the connection side of the joint outer part; a torque-transmitting ball between each first track pair and each second track pair; a ball cage arranged between the joint outer part and the joint inner part and having an inner surface of the cage, an outer surface of the cage and circumferentially distributed cage windows, each cage window receiving at least one of the torque-transmitting balls, wherein the balls are held by the ball cage when the longitudinal axes of the joint inner part and the joint outer part are coaxially aligned in a joint central plane; wherein the inner surface of the joint outer part forms a support surface towards the connection side, against which the ball cage can be axially abutted, in particular during installation; wherein one of the outer group of ball tracks and the inner group of ball tracks is machined hard; and the other of the outer group of ball tracks and the inner group of ball tracks is machined soft and hardened.

[0009] The advantages of a reverse track universal joint are that it can be manufactured cost-effectively due to the ball track set machined before hardening. In total, at the same time, due to the hardened and then hard-machined ball track set, the support surface of the universal joint outer part, and the reverse track shape, a good guiding and supporting function for the needle ball cage is obtained and thus high efficiency is achieved.

[0010] In the context of this disclosure text, soft machining especially includes that the desired ball track geometry is generated only by soft machining, that is to say, completed and finished before hardening. After hardening, no further machining for changing the geometry of the ball track is provided, especially no cutting machining. The ball track can be manufactured especially by forming, such as by forging, hot forming, cold forming, stamping, and / or hammering. The ball track can alternatively or complementarily also be machined cuttably at least in an intermediate arrangement, such as by a milling operation, a turning operation, and / or a grinding operation.

[0011] In the context of this disclosure text, hardening and hard machining especially further mean that the corresponding ball track set is prefabricated with a corresponding machining allowance before hardening and machined to the desired final geometry after hardening. Here, the prefabrication can be completed by cutting manufacturing methods, such as turning or milling, and / or by non-cutting manufacturing methods, such as forming, forging, or stamping. The machining can be carried out especially cuttably, such as by grinding or turning. Here, the machining allowance material of, for example, a few tenths of a millimeter of the corresponding surface specified in the intermediate product is removed after hardening.

[0012] For example, the ball track hard-machined by grinding or turning can have a smaller surface roughness than the soft-machined ball track, that is to say, the ball track not machined after hardening. The latter can optionally have a micro-structure generated by shot peening performed before hardening.

[0013] Preferably, the first outer ball track and the second outer ball track are designed such that, when observed in a cross-section, two-point contacts with the relevant torque-transmitting balls are respectively formed. Alternatively or complementarily, the first inner ball track and the second inner ball track can also be designed such that, when observed in a cross-section, two-point contacts with the relevant torque-transmitting balls are respectively formed. The two-point contact can be generated, for example, by a Gothic or elliptical track shape when observed in a cross-section. Through the two-point contact or two-point track, self-measurement of the ball track can be performed. But in principle, a circular track can also be used.

[0014] In principle, two implementation methods are possible, which are generated by assigning the ball tracks processed before or after hardening to the universal joint outer part or the universal joint inner part. According to the first implementation method, the ball tracks that are soft-machined before hardening can be assigned to the universal joint outer part, and the hardened and then hard-machined ball tracks are assigned to the universal joint inner part. According to a contrary alternative implementation scheme, the ball tracks that are soft-machined before hardening can be assigned to the universal joint inner part, and the hardened and then hard-machined ball tracks are assigned to the universal joint outer part.

[0015] Next, some possible design solutions will be described, which relate to the first implementation method. In the first implementation method, the ball tracks of the universal joint outer part are machined before hardening and the ball tracks of the universal joint inner part are machined after hardening. In the second implementation method, the features are correspondingly reversed. In the second implementation method, the soft-machined ball tracks are assigned to the universal joint inner part and the hard-machined ball tracks are assigned to the universal joint outer part.

[0016] According to a design solution, the inner surface of the outer part can be hardened and not mechanically machined after hardening. In other words, the geometry of the inner surface is made or completed before hardening. No further geometry-changing machining is provided for the inner surface after hardening, especially no cutting machining. The inner surface of the outer part can be made especially by forming, such as by forging, hot forming, stamping, and / or hammering. The inner surface of the outer part can alternatively or complementarily at least also be machined cuttably in an intermediate step, such as by a milling operation, a turning operation, and / or a grinding operation.

[0017] The outer surface of the universal joint inner part can be hardened and hard-machined after hardening. This means that the outer surface of the inner part is prefabricated with an appropriate machining allowance before hardening and is machined to the desired final geometry after hardening. Here, the prefabrication can be completed by cutting manufacturing methods, such as turning or milling, and / or by non-cutting manufacturing methods, such as forming or forging. The machining of the outer surface can be carried out especially cuttably, such as by grinding or turning.

[0018] According to a design solution, the outer surface of the cage of the ball cage can be soft-machined, hardened, and not mechanically machined after hardening. The inner surface of the cage can alternatively or complementarily be soft-machined, hardened, and remain not mechanically machined after hardening. The outer surface of the cage can be machined cuttably and / or non-cuttably, such as by forming, at least in some processes before the cage is hardened, for example by turning or grinding. The same description similarly also applies to the machining of the inner surface of the cage, which can be carried out non-cuttably and / or cuttably.

[0019] According to one design, when the longitudinal axes of the outer universal joint member and the inner universal joint member are flush with each other, the external radial clearance formed between the outer surface of the cage and the inner surface of the outer universal joint member and the internal radial clearance formed between the inner surface of the cage and the outer surface of the inner universal joint member may not be the same size. Similarly, the external total axial clearance formed between the outer surface of the cage and the inner surface of the outer universal joint member and the internal total axial clearance formed between the inner surface of the cage and the outer surface of the inner universal joint member may not be the same size. When the external ball track set is soft machined, the external radial clearance or the external total axial clearance is preferably greater than the internal radial clearance or the internal total axial clearance. When the internal ball track set is soft machined, the external radial clearance or the external total axial clearance is preferably less than the internal radial clearance or the internal total axial clearance. In addition, the universal joint components can also be designed such that when the inner universal joint member is axially centered relative to the ball cage, the external total axial clearance is asymmetrically divided into the axial clearance on the external open side and the axial clearance on the external connection side. Here, the axial clearance on the connection side is preferably less than the axial clearance on the open side. This advantageously supports the inner universal joint member in being axially supported against the support surface of the outer universal joint member through the ball cage when pressed into the shaft, without clamping the balls in the ball tracks or being in pressing contact with the ball tracks. Different design options for the radial clearance or the axial clearance contribute to simple and cost-effective manufacturing because a rough clearance is achieved in one of the four surface pairs.

[0020] The opposing surfaces of the outer universal joint member, the cage, and the inner universal joint member can in principle be freely selected as required. One, multiple, or all of the inner surface of the outer universal joint member, the outer surface of the cage, the inner surface of the cage, and the outer surface of the inner universal joint member can be designed as spherical, for example. These surfaces can alternatively or complementarily also have cylindrical, toroidal, and / or conical sections. When using a ball cage with spherical outer and inner surfaces, these spherical surfaces can be arranged coaxially with each other, that is to say, the two surface centers can coincide. According to an alternative feasible solution, the spherical surfaces can also be axially offset from each other, that is to say, the two surface centers of the inner and outer spherical ball surfaces have an axial spacing (offset) from each other. The same explanation similarly also applies to them when using the spherical inner surface of the outer member and / or the spherical outer surface of the inner member.

[0021] The first external ball track forms a first recess towards the open side and the second external ball track forms a second recess towards the open side. Here, it is particularly specified that the first recess of the first ball track opening towards the open side is smaller than the second recess of the second ball track opening towards the connection side.

[0022] The foregoing specific description relates to an embodiment in which the geometry of the ball tracks of the outer joint member is produced only by soft machining and the ball tracks of the inner joint member are hard machined. It goes without saying that in an alternative embodiment in which the ball tracks of the outer joint member are hard machined and the geometry of the ball tracks of the inner joint member is produced only by soft machining before hardening, the features are implemented correspondingly vice versa.

[0023] According to a design suitable for both of the above-described embodiments, at least a portion of the second outer ball track of the outer joint member has a pocket that is radially recessed relative to the functional section on the connection side, and the associated balls can be inserted radially into the pocket when the joint is overbent. In this way, the installation of the reverse track joint is facilitated.

[0024] According to another design suitable for both embodiments, the outer joint member and the inner joint member are designed such that they can be angularly displaced relative to each other by a bending angle (β) of up to 30°, in particular up to 25°. The first balls of the first track pair form a first partial circle diameter (PCDA), and the second balls of the second track pair form a second partial circle diameter (PCDB). The ratio of at least one of the first and second partial circle diameters to the maximum partial circle diameter (PCDS) of the insertion opening of the inner joint member is in particular less than 2.05 (PCDA / PCDS < 2.05 and / or PCDB / PCDS < 2.05). With this design, a particularly large torque can be transmitted by the joint at a small bending angle. Therefore, this design is particularly suitable for use in a non-steering rear axle, especially on the transmission side. However, applications with a large bending angle are also possible, for example for a front axle with wheel-side steering. Here, the joint can be designed for a bending angle greater than 45°. The joint can correspondingly also be designed such that the ratio of the ball partial circle diameter to the opening partial circle diameter is different from the above ratio and can in particular be between 1.5 and 3.0 (1.5 < PCDA / PCDS < 3.0 and / or 1.5 < PCDB / PCDS < 3.0). The ratio between the ball partial circle diameter and the ball diameter can for example be between 2.5 and 4.5.

[0025] The number of balls transmitting torque and accordingly the number of outer and inner ball tracks is preferably divisible by 2 and is in particular 8, although different numbers such as 6 or 10 are also possible.

[0026] The above task is further solved by a method for manufacturing a constant velocity joint in the form of a reverse track joint, the method comprising:

[0027] Manufacturing an outer joint member having a longitudinal axis, a connection side and an open side, an inner surface with a support surface acting axially towards the connection side, and a first outer ball track and a second outer ball track which together form an outer ball track set;

[0028] Manufacturing an inner joint member having a longitudinal axis, an outer surface, and a first inner ball track and a second inner ball track which together form an inner ball track set;

[0029] Manufacturing a ball cage having a cage axis, a cage inner surface, a cage outer surface, and cage windows which can be circumferentially distributed around the cage axis;

[0030] Inserting the inner joint member into the ball cage;

[0031] Inserting the ball cage into the outer joint member;

[0032] Rotating the inner joint member relative to the outer joint member such that the first inner ball track is opposed to the first outer ball track and forms a first track pair which extends towards the open side of the outer joint member in the angular position of the joint, and the second inner ball track is opposed to the second outer ball track and forms a second track pair which extends towards the connection side of the outer joint member in the angular position of the joint; inserting balls into the cage windows when the inner joint member and the outer joint member are bent relative to each other, wherein the first track pair and the second track pair respectively accommodate torque-transmitting balls, and wherein the balls are held by the ball cage when the longitudinal axes of the inner joint member and the outer joint member are coaxially aligned in the joint center plane; wherein one of the outer ball track set and the inner ball track set is soft pre-machined, then hardened and machined after hardening, for example by machining; and wherein the other of the outer ball track set and the inner ball track set is soft machined and then hardened, that is to say, remains un-machined or un-hardened mechanically after hardening.

[0033] A reverse track universal joint manufactured by the said method has the same advantages as described above. It goes without saying that all features relating to the product can be transferred to the said method, and conversely, all features relating to the method can be transferred to the product.

[0034] According to a possible method variant, the cage outer surface and / or the cage inner surface are soft machined, in particular by a forming process, and then hardened. After hardening, preferably no further machining of a given geometry or mechanically is provided.

[0035] The outer joint member and / or the inner joint member can be manufactured, for example, from quenched and tempered steel or case-hardened steel. Hardening of the ball tracks and optionally of the inner surface of the outer joint member can be carried out, for example, by case hardening, in particular by induction heating. The quenched and tempered steel or case-hardened steel case-hardened in this way provides a wear-free surface with a tough core after hardening. This also applies analogously to the outer surfaces of the ball tracks and optionally of the inner joint member, which can likewise be case-hardened. The inner joint member can alternatively also be case-carburized and hardened. In case-carburizing and hardening, a hardness gradient decreasing in the direction of the core hardness is produced from the outer surface of the component.

[0036] According to a first possible embodiment, the first and second outer ball tracks and the inner surface of the outer joint member can be soft-machined, in particular by a forming process, and thereafter the first and second outer ball tracks and optionally the inner surface of the outer joint member can be hardened. The first and second inner ball tracks and the outer surface of the inner joint member can be correspondingly soft-pre-machined, then hardened, and after hardening, hard-machined. According to a second possible embodiment, the machining of the outer joint member and of the inner joint member can be carried out in the reverse order.

[0037] What applies to both possible embodiments is that the outer surface of the cage and the inner surface of the outer joint member and, on the other hand, the inner surface of the cage and the outer surface of the inner joint member can be manufactured such that, in the installed and tensioned state of the cross-track joint, the outer radial clearance between the ball cage and the outer joint member and the inner radial clearance between the ball cage and the inner joint member are not the same size, and / or the outer axial clearance between the ball cage and the outer joint member and the inner axial clearance between the ball cage and the inner joint member are not the same size.

[0038] According to one design, the inner joint member can be manufactured such that a part of the cross-beams of the inner joint member has a flattened structure on both sides. In this way, the installation of the inner joint member into the ball cage can be simplified, wherein the shorter inner cross-beam can be inserted into the window of the ball cage when the longitudinal axis of the inner joint member intersects the cage axis.

[0039] According to another embodiment, at least a part of the second outer ball track of the outer joint member can be manufactured on the connecting side with pockets that are radially recessed relative to the functional section, and the relevant balls can be radially inserted into the pockets when the joint is overbent. This also helps to improve the installation. Description of the Drawings

[0040] Preferred embodiments will be explained below with the aid of the drawings.

[0041] Figure 1

[0042] A) In the longitudinal section in the lintel area,

[0043] B) In the longitudinal section in the first track pair,

[0044] C) In the longitudinal section in the second track pair,

[0045] D) In the simplified illustration in the longitudinal section with the first track pair in the lower half and the second track pair in the upper half of the figure,

[0046] shows the reverse track universal joint according to the invention in a first embodiment;

[0047] Figure 2

[0048] A) Coaxially aligned with the universal joint inner part and the universal joint outer part,

[0049] B) In the longitudinal section in the first track pair in the bending view,

[0050] C) In the longitudinal section in the second track pair in the bending view,

[0051] D) In the longitudinal section in the lintel area in the bending view,

[0052] shows the reverse track universal joint of Figure 1 with the inserted shaft;

[0053] Figure 3

[0054] A) In the three - dimensional view of the universal joint opening,

[0055] B) In the axial view of the universal joint opening,

[0056] C) In the longitudinal section along the cutting line 3C - 3C of Figure 3B in the lintel area,

[0057] D) In the longitudinal section along the cutting line 3D - 3D of Figure 3B in the first external ball track,

[0058] E) In the longitudinal section along the cutting line 3E - 3E of Figure 3B in the second external ball track,

[0059] shows the universal joint outer part of the reverse track universal joint of Figure 1;

[0060] Figure 4

[0061] A) In the three - dimensional view,

[0062] B) In the axial view,

[0063] C) In the longitudinal section in the first internal ball track along the Figure 4B cutting line 4C - 4C of

[0064] D) In the longitudinal section of the cutting line 4D-4D according to Figure 4B of the ball track in the second interior,

[0065] the universal joint internal part of the reverse track universal joint of FIG. 1 is shown;

[0066] Figure 5

[0067] A) In the three-dimensional view,

[0068] B) In the cross-section,

[0069] C) In the longitudinal section of two opposing cage windows,

[0070] the ball cage of the reverse track universal joint of FIG. 1 is shown;

[0071] Figure 6

[0072] A) In the three-dimensional view when the universal joint internal part penetrates into the ball cage at the intersection of the axes,

[0073] B) In the cross-section of the ball cage when penetrating as shown in FIG. 6A,

[0074] C) In the three-dimensional view after the universal joint internal part is coaxially aligned in the ball cage, the installation of the universal joint internal part and the ball cage of the reverse track universal joint of FIG. 1 is shown;

[0075] Figure 7

[0076] A) In the longitudinal section of the first track pair,

[0077] B) In the longitudinal section of the first track pair,

[0078] the installation when the universal joint internal part is overly bent relative to the universal joint external part is shown;

[0079] And

[0080] Figure 8 shows in longitudinal section the universal joint external part of the reverse track universal joint according to the invention in an altered embodiment;

[0081] And

[0082] Figure 9 shows in longitudinal section the universal joint external part of the reverse track universal joint according to the invention in another altered embodiment. Detailed Description

[0083] In the following jointly described Figures 1A to 7BIn the figure, a reverse track universal joint 11 according to the present invention is shown. The reverse track universal joint 11 includes a universal joint outer member 12, a universal joint inner member 13, a plurality of torque-transmitting balls 14A, 14B, and a ball cage 15. A surrounding gap 25 is formed between the spherical outer surface 16 of the ball cage 15 and the spherical inner surface 24 of the universal joint outer member 12. A surrounding gap 27 is also formed between the spherical inner surface 17 of the ball cage 15 and the spherical outer surface 26 of the universal joint inner member 13. In the present embodiment, the surface center points M16 and M17 are in a common universal joint center plane EM. In a modified embodiment, it is also possible that the surface center points M16 and M17 have axial spacings (offsets) with respect to the universal joint center plane EM in opposite directions. The balls 14A, 14B are held in the universal joint center plane EM in the circumferentially distributed cage windows 18 in the ball cage 15. A longitudinal axis L12 is marked at the universal joint outer member 12, and a longitudinal axis L13 is marked at the universal joint inner member 13. The intersection points of the longitudinal axes L12, L13 and the universal joint center plane EM form the universal joint center point M.

[0084] In the embodiment shown here, the inner surface 24 of the universal joint outer member 12, the cage outer surface 16, the cage inner surface 17, and the outer surface 27 of the universal joint inner member 13 are spherical. One or more of these surfaces may alternatively or complementarily also have cylindrical, toroidal, and / or conical sections. Regarding the inner surface 24 of the outer member 12, the open-side section 24a, the central region 24c, and the bottom-side section 24b are drawn in FIG. 3D. The bottom-side section 24b forms a support surface against which the ball cage 15 can axially rest with its outer surface 16.

[0085] The universal joint outer member 12 has a bottom 19 and an opening 20, and the bottom can be transformed into a connection pin, for example. The universal joint inner member 13 has an opening 21 into which the journal of the drive shaft 30 can be inserted in a torque-resistant manner for torque transmission. The reverse track universal joint 11 with the installed shaft 30 is shown in FIGS. 2A to 2D. The position of the bottom 19 hereinafter refers to the axial direction "towards the connection side", and the position of the opening 20 hereinafter refers to the axial direction "towards the opening side". These terms are also used for the universal joint inner member, where the actual connection of the shaft to the universal joint inner member 13 is still not considered. It is understood that the universal joint outer member can also be designed to be open towards the connection side instead of having a bottom, for example in the form of a disc universal joint.

[0086] On the circumference, a first track pair 22A, 23A with torque-transmitting first balls 14A and a second track pair 22B, 23B with torque-transmitting second balls 14B are alternately provided. Figure 1BThe shape of the first track pairs 22A, 23A is shown. Figure 1C The shape of the second track pairs 22B, 22B is shown. The first ball 14A has contacts with the first outer ball track 22A in the universal joint outer member and the first inner ball track 23A in the universal joint inner member. Here, the center point of the first ball 14A defines a first center line respectively when moving along the outer and inner first ball tracks 22A, 23A, and the center point of the second ball 14B defines a second center line respectively when moving along the outer and inner second ball tracks 22B, 23B.

[0087] When the universal joint outer member 12 and the universal joint inner member 13 are coaxially aligned, the tangents T22A, T23A to the ball 14A form an opening angle δA at the contact points with the first tracks 22A, 23A, and this opening angle opens towards the opening side. The second ball 14B is guided in the outer ball track 22B in the universal joint outer member 12 and in the inner ball track 23B in the universal joint inner member 13. The contact of the ball 14B with the track bottom of the ball track is shown, and the track bottom is not necessarily required. In the shown stretched position, the tangents T22B, T23B to the second ball 14B form a second opening angle δB at the contact points with the second tracks 22B, 23B, and it opens towards the connection side. In a modified track form of the reverse track universal joint, the opening angles oriented in the opposite axial direction may also cause a slightly bent position of the universal joint, especially up to 2°.

[0088] The first and second track pairs are respectively in the radial planes passing through the universal joint with their center lines. Each of the balls 14A, 14B is received in a cage window 18 of the ball cage 15. The radial planes have the same angular spacing from each other. The number of torque - transmitting balls 14A, 14B and accordingly the number of outer and inner ball tracks is currently eight, but is not limited to eight. Here, the two first track pairs 22A, 23A of the universal joint outer member 12 are opposed to each other in the opposite direction, and the two second track pairs 22B, 23B are opposed to each other in the opposite direction.

[0089] Next, the particularities of the reverse track universal joint 11 according to the invention are explored in more detail, especially the design of the first and second ball tracks 22A, 22B of the universal joint outer member 12 and the design of the first and second ball tracks 23A, 23B of the universal joint inner member 13, which are different from each other. The following definitions apply currently in connection with the reverse track universal joint according to the invention:

[0090] The universal joint bending angle β defines an angle that is sandwiched between the longitudinal axis L12 of the universal joint outer member 12 and the longitudinal axis L13 of the universal joint inner member 13. The universal joint bending angle β is zero when the universal joint is stretched.

[0091] The orbital bending angle β / 2 defines an angle by which the radius about the center point M of the cardan joint encloses the center plane EM of the cardan joint at the center of the ball. Here, the orbital bending angle β / 2 is always half of the cardan joint bending angle β at any angular position of the cardan joint.

[0092] The opening angle δ defines an angle which is enclosed by the tangent T to the ball at the contact point with the first or second ball track during the stretching of the cardan joint.

[0093] The control angle δ / 2 defines an angle which is enclosed by the tangent applied to the respective ball center line at the center point of the ball and the relevant longitudinal axis L of the outer or inner part of the cardan joint during the stretching of the cardan joint. Here, the control angle δ / 2 is equal to half of the opening angle δ.

[0094] The center plane EM is defined by the center points of the torque-transmitting balls 14A, 14B.

[0095] The first partial circle diameter PCDA defines the diameter formed by the center point of the first ball 14A during the stretching of the cardan joint.

[0096] The second partial circle diameter PCDB defines the diameter formed by the center point of the second ball 14B during the stretching of the cardan joint.

[0097] The partial circle diameter PCDS defines the diameter of the insertion opening of the inner part 13 of the cardan joint, in particular by the root line of the insertion opening.

[0098] The reverse track cardan joint 2 shown here is preferably designed such that the cardan joint parts 12, 13 are angularly displaced relative to each other by a bending angle β of up to a maximum of 30°. The ratio of the first and / or second partial circle diameter PCDA, PCDB to the maximum partial circle diameter PCDS of the insertion opening of the inner part 13 of the cardan joint is in particular less than 2.05 here, that is to say PCDA / PCDS < 2.05 and / or PCDB / PCDS < 2.05. With this design, it is in particular possible to transmit high torques by the reverse track cardan joint 2. It goes without saying, however, that depending on the application, other designs with larger bending angles β of more than 30°, in particular also more than 45°, are also used, as for example in the cardan joint on the wheel side of a steering axle.

[0099] According to the invention, on the one hand, the first and second outer ball tracks 22A, 22B, which can also be collectively referred to as the outer ball track or outer ball track group, and on the other hand, the first and second inner ball tracks 23A, 23B, which can also be collectively referred to as the inner ball track or inner ball track group, are manufactured differently.

[0100] Specifically, one of the external ball track group and the internal ball track group is hardened and particularly machined by cutting, while the other of the external ball track group and the internal ball track group is soft-machined, that is to say, it is not mechanically machined after hardening. Here, the soft-machined and then hardened ball tracks may be rougher than the ball tracks machined after hardening.

[0101] Next, an embodiment will be described in which the ball tracks 22A, 22B of the universal joint outer member 12 are soft-machined before hardening, and the ball tracks 23A, 23B of the universal joint inner member 13 are hard-machined after hardening.

[0102] The universal joint outer member 12 shown as a part in FIGS. 3A to 3E, in particular the first and second external ball tracks 22A, 22B, can be completed by a forming operation, such as by forging, hot forming, cold forming, stamping and / or hammering. It goes without saying that cutting intermediate steps, such as for peeling and / or deburring, may also be provided between the respective forming steps.

[0103] As can be seen especially from Figure 1B , 1D the lower half views, 2C and 3D, of, the first external ball track 22A has an arcuate central functional section. The center point of the arc forming the central functional section is offset towards the opening side with respect to the central plane of the universal joint 1, which is also called an axial offset, with an offset plane EA. At the end of its opening side, the first external ball track 22A of the universal joint outer member 12 has a radial expansion structure 28A to facilitate the insertion of the relevant ball 14A during installation. In addition, due to the radial expansion structure 28A on the opening side of the first ball track 22A, the radial side recess formed by the central functional section becomes smaller. This in turn has several advantages when shaping the universal joint outer member 12, because little material flows or presses radially inwards during forming. At the end of its bottom side, the first external ball track 22A of the universal joint outer member 12 has a pocket 29A that is recessed radially with respect to the functional section. As shown in Figure 7A , when inserting the ball 14Aa inserted on the opening side during installation, the completely opposite ball 14Ab can be inserted into the pocket 29A on the bottom side. This facilitates the installation of the reverse track universal joint 11.

[0104] As can be seen especially from Figure 1C , 1DAs can be seen from the upper half views, 2B and 3E, the second outer ball track 22B has an arcuate central functional section. The center point of the bottom of the central functional section is offset relative to the central plane EM of the universal joint 11 towards the bottom side into the plane EB. At the end of its bottom side, the second outer ball track 23B of the universal joint outer member 12 has a pocket 29B that is radially concave relative to the functional section. As shown in Figure 7B , when the ball 14Ba is inserted on the mounting opening side, the ball 14Bb that is completely oppositely positioned can be inserted into the pocket 29B on the bottom side. This facilitates the installation of the reverse track universal joint 11.

[0105] The first outer ball track 22A forms a first side recess H22A towards the opening side, and the second outer ball track 23B forms a second side recess H22B towards the opening side. Here, in particular, as can be seen in Figure 1D , the first side recess H22A of the first ball track 22A that opens towards the opening side is smaller than the second side recess H22B of the second ball track 22B that opens towards the connection side.

[0106] In the current universal joint outer member 12, the spherical surface 24 is preferably also soft-machined, which means that the spherical surface remains unmachined mechanically after hardening. Thus, the entire internal contour of the universal joint inner member 12 with the ball tracks 22A, 22B and the sphere 24 is completed before hardening. After hardening, no further machining for changing the geometry is provided. It has proven advantageous here that the outer member inner surface 24 together with the first and second outer ball tracks 22A, 22B can be manufactured by a forming operation as explained above. The forming process offers the advantages of particularly fast and cost-effective manufacturing.

[0107] The first and second outer ball tracks 22A, 22B are shaped in particular such that a two-point contact with the associated balls 14A, 14B is formed in the cross-section of the respective ball track. The two-point contact can be produced, for example, by a Gothic or elliptical track shape in the cross-section.

[0108] As a part in Figures 4A to 4DThe manufacture of the inner part 13 of the universal joint shown in the figure, in particular the first and second inner ball tracks 23A, 23B, can be accomplished by cutting processes, such as turning and / or milling, wherein manufacture by means of forming operations is also possible. The inner ball tracks 23A, 23B can be prefabricated with corresponding machining allowances before hardening. After hardening, the inner ball tracks 23A, 23B are machined into the desired final geometry. Machining is carried out in particular by cutting, for example by grinding and / or turning operations. The first and second inner ball tracks 23A, 23B are preferably also designed in such a way that in the cross section of the corresponding ball tracks, two-point contact with the associated balls 14A, 14B is formed.

[0109] In the present embodiment, the spherical inner surface 26 of the joint inner part 13 is preferably also first soft pre-machined, then hardened and hard machined after hardening. The pre-machined can be done by a cutting manufacturing process, such as turning or milling, and / or by a non-cutting manufacturing process, such as forming or forging. The machining of the outer surface 26 of the joint inner part is particularly carried out by cutting, for example by grinding.

[0110] As especially in Figure 4A , 4B As can be seen in FIGS. 6A and 6B, the joint inner part 13 in the present embodiment has two diametrically opposed webs 33m with flattened structures 35A, 35B on both sides. The axial length L33m of the webs 33m is therefore smaller than the minimum circumferential extension L18 of the cage window 18, so that the webs 33m can be inserted into the window 18 of the ball cage 15 when the joint inner part 13 is aligned with the longitudinal axis L13 intersecting the cage axis L15, as shown in FIGS. 6A and 6B.

[0111] Also used as parts in Figures 5A to 5C The ball cage 15 shown in the figure has, in the present embodiment, in particular, a spherical outer surface 16 and a spherical inner surface 17 which are soft-machined and subsequently hardened. The soft machining of the spherical surfaces 16, 17 can be performed, for example, by turning or grinding and / or without cutting, for example by forming. The walls of the cage window 18 which guide the balls 14A, 14B laterally are preferably hard-machined, in particular ground, after hardening.

[0112] Especially in Figure 1DAs can be seen, the external clearance 25 formed between the spherical outer surface 16 of the ball cage 15 and the spherical inner surface 24 of the universal joint outer member 12 is greater than the internal clearance 27 formed between the spherical inner surface 17 of the ball cage 15 and the spherical outer surface 26 of the universal joint inner member 13. Correspondingly, the external axial clearance between the ball cage 15 and the universal joint outer member is greater than the internal axial clearance between the ball cage 15 and the universal joint inner member 13.

[0113] The spherical surfaces 24, 16, 17, 26 of the universal joint members 12, 13, 15 are designed such that, in the installed state of the universal joint 11 (in this installed state, the equator of the spherical surface 26 of the universal joint outer member 12 and the equator of the spherical cage outer surface 16 are in one plane, and the equator of the spherical cage inner surface 17 and the equator of the spherical surface 26 of the universal joint inner member 13 are in one plane), the external radial clearance 25 is greater in the direction of the open side than in the direction of the connection side. The universal joint inner member 13 can thereby be axially braced against the universal joint outer member 12 via the ball cage 15 when being pressed onto the shaft 30 without clamping the balls 14A, 14B in the ball tracks 22A, 23A; 22B, 23B. In the present embodiment, the two spherical inner and outer surfaces 24, 26 of the ball cage 15 are arranged coaxially with each other.

[0114] The method for manufacturing the reverse track universal joint 11 according to the invention comprises the following steps: manufacturing the universal joint outer member 12; manufacturing the universal joint inner member 13; manufacturing the ball cage 15; inserting the universal joint inner member 13 into the ball cage 15; inserting the ball cage 15 into the universal joint outer member 12; rotating the universal joint inner member 13 relative to the universal joint outer member 12 such that the first internal ball track 23A is opposed to the first external ball track 22A and forms a first track pair, the first track pair extending towards the open side of the universal joint outer member 12, and the second internal ball track 23B is opposed to the second external ball track 22B and forms a second track pair, the second track pair extending towards the connection side of the universal joint outer member 12; inserting the balls 14A, 14B into the cage windows 18 when the universal joint inner member and the universal joint outer member are bent relative to each other. The first track pair and the second track pair each accommodate one of the torque-transmitting balls 14A, 14B, wherein the balls are held by the ball cage in the universal joint center plane EM when the longitudinal axes of the universal joint inner member and the universal joint outer member are coaxially aligned. It is provided that one of the external ball track group and the internal ball track group is soft pre-machined, then hardened and machined cuttably after hardening, and the other of the external ball track group and the internal ball track group is soft machined and then hardened, that is to say, not machined further after hardening.

[0115] On the one hand, the cage outer surface 16 of the ball cage 15 and the inner surface 24 of the universal joint outer member 12, and on the other hand, the cage inner surface 17 of the ball cage and the outer surface 26 of the universal joint inner member 13 can be manufactured in particular such that in the installed and tensioned state of the reverse track universal joint 11, the external longitudinal axial clearance So between the ball cage 15 and the universal joint outer member 12 and the internal total axial clearance Si between the ball cage 15 and the universal joint inner member 13 are not the same. As shown in Figure 1D As shown, the external total axial clearance So consists of the external open-side axial clearance Soa and the connection-side axial clearance Sob between the cage 15 and the outer member 12. Similarly, the internal total axial clearance Si consists of the internal open-side axial clearance Sia and the connection-side axial clearance Sib between the cage 15 and the inner member 13.

[0116] FIG. 8 shows the universal joint outer member 12 in a modified embodiment, in which the second external ball track 22B has an expanded structure 34 at the open-side end, so that the radial side recess H22B becomes smaller. In addition, the universal joint inner member 13 and all the remaining universal joint parts can be designed as described in connection with Figures 1A to 7B as explained.

[0117] FIG. 9 shows the reverse track universal joint 2 according to the invention in another modified embodiment. This reverse track universal joint corresponds as much as possible to Figures 1A to 7B the embodiment shown in, and in this regard reference can be made briefly to the description thereof. Here, the same or corresponding parts are provided with the same reference numerals. Here, the first track pair 22A, 23A is shown in the lower half of the figure and the second track pair 22B, 23B is shown in the upper half of the figure. The particularity of the current embodiment according to FIG. 9 is that the inner surface 24 of the universal joint outer member 12 is designed cylindrically towards the open side starting from the central plane EM. The open-side section 24a has no side recess in this regard. The bottom-side section 24c of the inner surface 24 forms the support surface of the ball cage 15, as in the above embodiment.

[0118] List of reference numerals

[0119] 11 Reverse track universal joint

[0120] 12 Universal joint outer member

[0121] 13 Universal joint inner member

[0122] 14A, 14B Balls

[0123] 15 Ball cage

[0124] 16 Spherical outer surface (15)

[0125] 17 Spherical inner surface (15)

[0126] 18 Window

[0127] 19 Connecting side

[0128] 20 Opening side

[0129] 21 Opening

[0130] 22 External ball track

[0131] 23 Internal ball track

[0132] 24 Spherical inner surface (12)

[0133] 25 External clearance

[0134] 26 Spherical outer surface (13)

[0135] 27 Internal clearance

[0136] 28 Radial expansion structure

[0137] 29 Pocket

[0138] 30 Shaft

[0139] 32 Lintel (12)

[0140] 33 Lintel (13)

[0141] 34 Expansion structure

[0142] 35A, 35B Flattened structure

[0143] 36 Opening

[0144] L Longitudinal axis

[0145] M Cardan center point

[0146] EM Cardan center plane

[0147] T Tangent

[0148] EA First offset plane

[0149] EB Second offset plane

[0150] Si Total internal axial clearance

[0151] So Total external axial clearance

[0152] PCD Pitch circle diameter

[0153] β universal joint bending angle

[0154] δ opening angle.

Claims

1. Reverse track universal joint, comprising: A universal joint outer member (12) having a longitudinal axis (L12), a connection side and an open side, and a first outer ball track (22A) and a second outer ball track (22B). The first outer ball track and the second outer ball track are arranged circumferentially in the inner surface (24) of the universal joint outer member (12). The first outer ball track and the second outer ball track are at least partially curved in a longitudinal section, and the first outer ball track and the second outer ball track form an outer ball track group; A universal joint inner member (13) having a longitudinal axis (L13) and a first inner ball track (23A) and a second inner ball track (23B). The first inner ball track and the second inner ball track are arranged circumferentially in the outer surface (26) of the universal joint inner member (13). The first inner ball track and the second inner ball track are at least partially curved in a longitudinal section, and the first inner ball track and the second inner ball track form an inner ball track group; wherein the first outer ball track (22A) and the first inner ball track (23A) form a first track pair (22A, 23A) with each other, and the first track pair extends towards the open side of the universal joint outer member (12), and wherein the second outer ball track (22B) and the second inner ball track (23B) form a second track pair (22B, 23B) with each other, and they extend towards the connection side of the universal joint outer member (12), one torque-transmitting ball (14A, 14B) in each first track pair (22A, 23A) and each second track pair (22B, 23B), A ball cage (15) is arranged between the universal joint outer member (12) and the universal joint inner member (13) and has a cage inner surface (17), a cage outer surface (16), and circumferentially distributed cage windows (18). The cage windows respectively accommodate at least one of the torque-transmitting balls (14A, 14B). Wherein, the balls (14A, 14B) are held by the ball cage (15) when the longitudinal axes (L12, L13) of the universal joint inner member (13) and the universal joint outer member (12) are coaxially aligned on the universal joint center plane (EM). And wherein, the inner surface (24) of the universal joint outer member (12) forms a support surface towards the connection side, and the ball cage (15) can axially rest against the support surface, characterized in that 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 machined before hardening, that is to say, it is not mechanically machined after hardening.

2. The reverse track universal joint according to claim 1, characterized in that the other of the outer ball track group and the inner ball track group is machined by non-cutting forming.

3. The reverse track universal joint according to claim 1 or 2, characterized in that At least one of the outer surface (16) and the inner surface (17) of the cage is soft-machined and hardened.

4. The reverse track universal joint according to claim 1 or 2, characterized in that when the longitudinal axes (L12) of the universal joint outer member (12) and the longitudinal axes (L13) of the universal joint inner member (13) are flush with each other, an external radial clearance (25) formed between the outer surface (16) of the cage and the inner surface (24) of the universal joint outer member (12) and an internal radial clearance (27) formed between the inner surface (17) of the cage and the outer surface (26) of the universal joint inner member (13) are not of the same size; wherein when the external ball track set is machined before hardening, the external radial clearance (25) is greater than the internal radial clearance (27), and when the internal ball track set is machined before hardening, the external radial clearance (25) is less than the internal radial clearance (27).

5. The reverse track universal joint according to claim 1 or 2, characterized in that when the universal joint outer member (12) and the universal joint inner member (13) are coaxially aligned, an external total axial clearance (So) formed between the outer surface (16) of the cage and the inner surface (24) of the universal joint outer member (12) and an internal total axial clearance (Si) formed between the inner surface (17) of the cage and the outer surface (26) of the universal joint inner member (13) are not of the same size; wherein when the external ball track set is machined before hardening, the external total axial clearance (So) is greater than the internal total axial clearance (Si), and when the internal ball track set is machined before hardening, the external total axial clearance (So) is less than the internal total axial clearance (Si).

6. The reverse track universal joint according to claim 5, characterized in that when the universal joint inner member (13) is axially centered relative to the ball cage (15) with respect to the internal total axial clearance (Si), the external total axial clearance (So) is asymmetrically divided into an external open-side axial clearance (Soa) and an external connection-side axial clearance (Sob).

7. The reverse track universal joint according to claim 1 or 2, characterized in that the first external ball track (22A) has a first external side recess (H22A) on the open side, and the second external ball track (22B) has a second external side recess (H22B) on the open side, wherein the first external side recess (H22A) is smaller than the second external side recess (H22B).

8. The reverse track universal joint according to claim 1, characterized in that the first external ball track (22A) and the second external ball track (22B) of the universal joint outer member (12) are soft-machined and hardened, and the first internal ball track (23A) and the second internal ball track (23B) of the universal joint inner member (13) are hardened and hard-machined.

9. The reverse track universal joint according to claim 8, It is characterized in that, the inner surface (24) of the universal joint outer member (12) is soft-machined and hardened, and the outer surface (26) of the universal joint inner member (13) is hardened and hard-machined after hardening.

10. The reverse track universal joint according to claim 8 or 9, It is characterized in that, the first outer ball track (22A) and the second outer ball track (22B) are shaped-machined before hardening; and the first inner ball track (23A) and the second inner ball track (23B) are cut-machined after hardening.

11. The reverse track universal joint according to claim 1 or 2, It is characterized in that, the first outer ball track (22A) and the second outer ball track (22B) of the universal joint outer member (12) are hardened and hard-machined after hardening, and the first inner ball track (23A) and the second inner ball track (23B) of the universal joint inner member (13) are soft-machined and hardened.

12. The reverse track universal joint according to claim 1 or 2, It is characterized in that, the first outer ball track (22A) and the second outer ball track (22B) are designed such that, when observed in a cross-section, two-point contacts with the relevant torque-transmitting balls (14A, 14B) are respectively formed, and / or the first inner ball track (23A) and the second inner ball track (23B) are designed such that, when observed in a cross-section, two-point contacts with the relevant torque-transmitting balls (14A, 14B) are respectively formed.

13. The reverse track universal joint according to claim 1 or 2, It is characterized in that, at least a part of the second outer ball track (22B) of the universal joint outer member (12) has a pocket (29B) that is radially concave with respect to the functional section at the connection side, and when the reverse track universal joint (11) is overly bent, the relevant ball (14B) can be inserted radially into the pocket.

14. The reverse track universal joint according to claim 1 or 2, It is characterized in that, the outer surface (26) of the universal joint inner member (13) is formed by a plurality of circumferentially distributed webs (33), wherein a part of the webs (33m) have flattened structures (35A, 35B) on two axial sides, and thus the axial length (L33m) of the part of the webs (33m) is less than the circumferential extension length (L18) of the cage window (18) of the ball cage (15).

15. The reverse track universal joint according to claim 1 or 2, It is characterized in that, the universal joint outer member (12) and the universal joint inner member (13) are designed such that the universal joint inner member (13) can perform an angular movement with respect to the universal joint outer member (12) up to a bending angle (β) of 30° at most; and the first ball (14A) of the first track pair forms a first partial circle diameter (PCDA), and the second ball (14B) of the second track pair forms a second partial circle diameter (PCDB), Wherein, the ratio of at least one of the first and second partial circle diameters (PCDA, PCDB) to the largest partial circle diameter (PCDS) of the insertion opening (36) of the universal joint inner member (13) is less than 2.

05.

16. A method for manufacturing a reverse track universal joint, comprising: Manufacturing a universal joint outer member (12) having: a longitudinal axis (L12), a connection side and an opening side, an inner surface (24) with a support surface acting axially towards the connection side, and a first outer ball track (22A) and a second outer ball track (22B) forming an outer ball track group; Manufacturing a universal joint inner member (13) having: a longitudinal axis (L13), an outer surface (26), and a first inner ball track (23A) and a second inner ball track (23B) forming an inner ball track group; Manufacturing a ball cage (15) having: a cage axis (L15), a cage inner surface (17), a cage outer surface (16), and cage windows (18) circumferentially distributed around the cage axis (L15); Inserting the universal joint inner member (13) into the ball cage (15); Inserting the ball cage (15) into the universal joint outer member (12); Rotating the universal joint inner member (13) relative to the universal joint outer member (12) such that the first inner ball track (23A) faces the first outer ball track (22A) and forms a first track pair that extends towards the opening side of the universal joint outer member (12), and the second inner ball track (23B) faces the second outer ball track (22B) and forms a second track pair that extends towards the connection side of the universal joint outer member (12); Inserting balls (14A, 14B) into the cage windows (18) when the universal joint inner member (13) and the universal joint outer member (12) are bent excessively relative to each other, wherein the first track pair and the second track pair respectively accommodate torque-transmitting balls (14A, 14B), and wherein the balls (14A, 14B) are held by the ball cage (15) when the longitudinal axes (L12, L13) of the universal joint inner member (13) and the universal joint outer member (12) are coaxially aligned in the universal joint center plane (EM); Characterized in that, One of the outer ball track group and the inner ball track group is soft pre-machined, then hardened and hard-machined after hardening; The other of the outer ball track group and the inner ball track group is soft-machined and then hardened, that is, remains un-machined after hardening.

17. The method according to claim 16, Characterized in that, At least one of the cage outer surface (16) and the cage inner surface (17) is soft-machined and then hardened.

18. The method according to claim 16 or 17, Characterized in that, The first external ball track (22A), the second external ball track (22B) and the inner surface (24) of the universal joint outer member (12) are soft machined, and then the first external ball track (22A) and the second external ball track (22B) of the universal joint outer member (12) are hardened, and The first internal ball track (23A), the second internal ball track (23B) and the outer surface (26) of the universal joint inner member (13) are soft pre-machined, then hardened, and then hard machined.

19. The method according to claim 16 or 17, characterized in that on the one hand the cage outer surface (16) and the inner surface (24) of the universal joint outer member (12) and on the other hand the cage inner surface (17) and the outer surface (26) of the universal joint inner member (13) can be manufactured such that, in the installed and stretched state of the counter-track universal joint, the external radial clearance (25) between the ball cage (15) and the universal joint outer member (12) and the internal radial clearance (27) between the ball cage (15) and the universal joint inner member (13) are not the same size, or the external axial clearance (So) between the ball cage (15) and the universal joint outer member (12) and the internal axial clearance (Si) between the ball cage (15) and the universal joint inner member (13) are not the same size.

20. The method according to claim 16 or 17, characterized in that a part of the crossbeam (33m) of the universal joint inner member (13) is manufactured with flattened structures (35A, 35B) on both sides, thus enabling penetration into the cage window (18) of the ball cage (15) for installation, and / or at least a part of the second external ball track (22B) of the universal joint outer member is manufactured with a pocket (29B) that is radially recessed relative to the functional section on the connection side, and the relevant second ball (14B) can be radially inserted into the pocket when the counter-track universal joint (11) is overbent.

Images