Patent Publication Number: US-2012034982-A1

Title: Cv joint with improved assembly properties

Description:
This nonprovisional application is a continuation of International Application No. PCT/EP2010/051159, which was filed on Feb. 1, 2010 and which claims priority to German Patent Application No. DE 10 2009 000 560.9, which was filed in Germany on Feb. 2, 2009 and which are all herein incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to constant velocity pivot joints having the features of the generic portion of the main claims. Such constant velocity pivot joints, which are intended for example for use in motor vehicles, are also known as homokinetic pivot joints. 
     BRIEF DESCRIPTION OF RELATED ART 
     A generic constant velocity pivot joint is known from DE 103 25 116 A1, which in turn is based on a generic constant velocity pivot joint known from DE 102 06 733 A1. The disclosure of these two patent applications is hereby adopted by reference in its entirety as the disclosure of this application. The constant velocity pivot joint disclosed in the first specification has a bell-shaped outer joint part with three guideways distributed over the circumference and extending in the axial direction. An inner joint part with three pivot pins, which are distributed over the circumference and extend in the radial direction and comprise a roller bearing surface, is disposed therein. The pivot pins are provided to come into engagement with the guideways in the outer joint part. For this purpose, so-called rollers are disposed between the outer joint part and the inner joint part, with each roller comprising an inner ring with an inner roller surface, the shape of which is adapted to the roller bearing surface of the pivot pins in such a way that a pivot pin of the inner joint part inserted into the inner ring can execute a tilting movement in the inner ring, but not a linear displacing movement. Furthermore, a roller comprises an outer ring with an outer roller surface, the shape of which is adapted to the guideways of the outer joint part in such a way that an outer ring inserted into a guideway can execute a linear displacing movement therein, but not a tilting movement. 
     BRIEF SUMMARY OF THE INVENTION 
     Two radially outwardly extending circumferential flanges are formed on the inner ring. A set of rolling members, such as needle bearings, is placed between these circumferential flanges. The rolling members roll off on the cylindrical outer surface of the inner ring. In this case, the distance between the circumferential flanges in the axial direction substantially corresponds to the length L of the rolling members. The outer ring of the roller forms a cylindrical inner surface on which the rolling members roll off. The thickness of the outer ring in the axial direction, in particular the width of the cylindrical inner surface is in this case much larger than the length L. This design permits a relatively large axial displacement or offset between the inner ring and the outer ring of the roller, with the inner ring, due to the design, and independent from the tilt on the pivot pin bearing it as well as independent from the position of the outer ring within the guideway, always being in contact with the rollers over their entire length L. This type of roller is referred to as “dynamic bearing” in the context of the present invention, and has proved itself in many cases in practical use. 
     The design known from DE 103 25 116 A1 realizes particular advantages with regard to low friction and vibration-free operation of the constant velocity pivot joint. However, the design known from the above-mentioned application has drawbacks with regard to its assembly if the constant velocity pivot joint is supposed to be delivered not in a completely pre-assembled state, but if the inner joint part is rather to be mounted in the outer joint part, for example, only during the final assembly of the motor vehicle. Since the rollers can be pivoted on the pins of the inner joint part, and furthermore since the outer rings of the rollers can be axially displaced relative to the inner rings, a defined assembly position of the pre-assembled inner joint part including the rollers supported by the pins cannot be ensured. Rather, in the design known from DE 103 25 116 A1, such states of the rollers frequently occur, with regard to the tilt angle and the axial displacement of the outer ring relative to the inner ring, which render an insertion of the rollers into the guideways of the outer joint part virtually impossible without manual correction of the angle or correction of the axial displacement of the outer ring relative to the inner ring. However, because of the number of the rollers to be adjusted—three per joint—and due to the adversely limited space available under the motor vehicle, such a manual correction is frequently virtually impossible. 
     This is where the invention comes in, which has set itself the object to propose a constant velocity pivot joint that enables a simplified final assembly of the joint within the context of the assembly in a motor vehicle or during the manufacture thereof, while maintaining the positive running properties of the aforementioned constant velocity pivot joint. 
     This object is achieved by a constant velocity pivot joint having the features of the independent claim. The dependent claims relate to advantageous embodiments which can be freely combined with one another within the context of what is technically feasible. 
     The present invention provides a constant velocity pivot joint comprising an outer joint part with three guideways distributed over the circumference and extending in the axial direction. An inner joint part with three pivot pins, which are distributed over the circumference and extend in the radial direction and comprise a roller bearing surface each, is disposed therein. The pivot pins are provided to come into engagement with the guideways. Rollers are disposed between the outer joint part and the inner joint part, with each roller comprising an inner ring with an inner roller surface, the shape of which is adapted to the roller bearing surface of the pivot pins in such a way that a pivot pin of the inner joint part inserted into the inner ring can execute a tilting movement therein, but not a linear displacing movement. Furthermore, the rollers comprise an outer ring with an outer roller surface, the shape of which is adapted to the guideways of the outer joint part in such a way that an outer ring inserted into a guideway can execute a roll-off movement therein, but not a tilting movement. A plurality of rolling members is disposed between the inner ring and the outer ring so that the outer ring can roll off on the inner ring. The entirety of the inner ring, outer ring and the rolling members is in this case also referred to as the roller of the constant velocity pivot joint. 
     The inner ring and the outer ring are axially displaceable relative to each other, with the inner ring forming an axial guide in a first embodiment, which fixes the position of the rolling members relative to the inner ring in the axial direction. In an alternative but equivalent embodiment, the outer ring forms an axial guide which fixes the position of the rolling members relative to the outer ring in the axial direction. 
     According to the invention, the inner rings respectively supported on a pivot pin have a rest position in which the inner ring is mechanically fixed in a defined angular position relative to the pin axis. In particular, the axis of rotation R of the roller can in this case coincide with the pin axis Z; however, this is not an absolute requirement. In particular, this means that, in order to tilt an inner ring from its rest position relative to the pin axis Z, a defined minimum torque has to be applied at least once. 
     In a first preferred embodiment, it is provided that the inner rings are elastically biased against tilting from the rest position, i.e. a defined minimum torque has to be overcome again for each tilting process from the rest position. This can be realized, for example, by means of a resilient means which can be disposed, for example, on the pin neck. 
     In an alternative second embodiment, it can also be provided that a defined minimum torque (tilting moment) has to be applied only once in order to tilt the inner rings from their respective rest position. Such a behavior can be caused by means that provide a mechanical barrier against tilting that is eliminated by a (substantially singular) plastic deformation of, for example, the roller bearing surface of the pivot pins or of the inner surface of the inner rings. Such a plastic deformation can occur, for example, when the vehicle is put into operation. 
     In a particularly preferred development, the above-mentioned minimum torque, which is to be applied once or permanently, is dependent upon the tilting direction of the inner ring relative to the pin axis. In this case, it can, for example, be provided that the torque required for tilting in a plane that is oriented in the direction of the pin axis and intersects the roller bearing surfaces of the pivot pin is significantly larger than the torque required for tilting in a plane that is also oriented in the pin axis but does not intersect the roller bearing surfaces. 
     Preferably, the above-mentioned means which mechanically fixes the inner ring in its rest position is disposed in the contact area between the inner ring and the pivot pin. Particularly preferably, the means comprises a circlip. 
     Alternatively or additionally, the means can comprise one or more geometrical structures that stand up in the contact area between the inner ring and the pivot pin from the roller bearing surfaces of the pivot pins and/or from the inner roller surfaces of the inner rings. Such geometrical structures can be produced, for example, by means of (local) plastic deformation of the pivot pins and/or of the inner rings, in particular subsequent to the inner rings being mounted onto the pivot pin. By way of example, mention is made herein of point-shaped local deformations (produced by means of a center punch) or even larger local deformations (produced by caulking). 
     Alternatively, such geometrical structures can be produced already during the forming of the pivot pins and/or of the inner rings, i.e., as a rule, prior to the inner rings being mounted on the pivot pin. In particular, such structures can be forged on or be produced by means of grinding. 
     Particular advantages with regard to the assembly of a constant velocity pivot joint according to the invention are obtained in another particularly preferred development. In this development, which can be combined individually or in combination with each of the above-described embodiments, the ring of the roller that does not form the axial guide for the rolling members forms an inner displacement stop as well as an outer displacement stop which extend in the radial direction inwardly (embodiment on the outer ring) or outwardly (embodiment on the inner ring), respectively. The displacement stops limit the roll-off movement of the rolling members on the inner surface of the outer ring or the outer surface of the inner ring, respectively, in the axial direction. The axial displaceability of the outer ring relative to the inner ring is limited in this manner. 
     If the length of the rolling members is L and the distance of the inner displacement stop from the outer displacement stop in the axial direction is d, the axial displaceability of the outer ring relative to the inner ring is limited to the difference D, i.e. 
     
       
      
       D=d−L  
      
     
     On the one hand, the configuration according to the invention of inner and outer displacement stops prevents with certainty the roller from falling apart both during the final assembly of the constant velocity pivot joint as well as—in its assembled state—in the case of large articulation angles of the joint. On the other hand, it permits the limitation of the axial displaceability of the rollers of the joint to an amount that is required in practical use due to the maximum obtainable bending of the constant velocity pivot joint. The limitation of the axial displaceability of the roller enables a significant reduction of the manual position corrections on the rollers required when the inner joint part and the outer joint part are joined. This results in considerable advantages during the final assembly of the constant velocity pivot joint according to the invention within the context of mounting the joint in a motor vehicle, in particular during the production thereof. 
     Particular advantages are the result with regard to the wear resistance of the roller in which the inner and outer displacement stops are formed on the outer ring if at least one of the displacement stop, but preferably both, do not reach over the outer contour of the inner ring. 
     If, however, the inner and outer displacement stops are formed on the inner ring of the roller, it has proved to be advantageous if at least one of the displacement stops, but preferably both, do not reach over the inner contour of the outer ring. 
     In both cases, the stop(s), at a maximum displacement of the rings of the rollers relative to each other, rest(s) against the rotating rolling members and not against the other ring of the roller, which causes a significant reduction of friction occurring in the roller. 
     Particularly long operating life of the constant velocity pivot joint according to the invention can be realized by the inner ring being formed integrally, and not in parts. By suitably shaping the heads of the inner joint part as only partially spherical surfaces, a capability of the inner ring of being mounted on the heads of the inner joint part in a special mounting position can nevertheless be ensured. 
     In a preferred embodiment of the constant velocity pivot joint according to the invention, at least one of the inner displacement stop and the outer displacement stop is formed integrally with the ring of the roller on which they are disposed. In this case, a displacement stop can preferably be formed as, for example, an annular contact shoulder. Such a contact shoulder can be formed, for example, prior to the completion of processing of the inner or outer ring, such as during the forging of the ring or when it is machined. Alternatively, a displacement stop can be formed also after the completion of processing of the inner or outer ring, e.g. by plastic deformation of the ring concerned by means of crimping or caulking. 
     Alternatively, at least one of the inner displacement stop and the outer displacement stop can be formed as a separately formed circlip. The use of, for example, a spring ring which is inserted into a groove formed on the inner ring or outer ring, respectively, is conceivable. Also conceivable is the use of an annular disk that is pushed onto the cylindrical inner or outer surface of the outer or inner ring, respectively. The position of the annular disk can then be fixed by, for example, caulking. On one side, the annular disk can also be supported by a resting shoulder formed on the cylindrical surface. 
     Other features and advantages become apparent from the dependent claims and the exemplary embodiments, which are to be understood as not having a limiting effect and which will be explained below with reference to the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG. 1  shows an exploded perspective view of a known constant velocity pivot joint, 
         FIG. 2  shows a perspective view of the outer joint member of the known constant velocity pivot joint (a “tulip”), 
         FIG. 3  shows a longitudinal section of the articulation of the known constant velocity pivot joint and of the pivoting process of the inner joint part within the roller, 
         FIG. 4  shows a perspective view of the inner joint part of the present constant velocity pivot joint (a “tripod star”), 
         FIG. 5  shows a top view in the axial direction onto the tripod star from  FIG. 4 , 
         FIG. 6  shows a top view in the axial direction onto the inner joint part of a constant velocity pivot joint according to the invention with a mounted roller, 
         FIG. 7  shows a section perpendicular to the axial direction through the inner joint part and the mounted roller from  FIG. 6 , 
         FIG. 8  shows a section perpendicular to the radial direction along the line A-A in  FIG. 6  through the inner joint part and the mounted roller, 
         FIG. 9  shows a section through a roller according to the invention, 
         FIG. 10  shows a detailed view of the section from  FIG. 9 , 
         FIG. 11  shows a first detail from  FIG. 7  in which the outer ring of the roller is in its outermost radial position, 
         FIG. 12  shows a second detail from  FIG. 7  in which the outer ring of the roller is in its innermost radial position, 
         FIG. 13  shows a schematic representation of the practical difficulties that can occur when the inner joint part and the outer joint part are joined, 
         FIG. 14  shows a schematic representation of a first preferred development of a constant velocity pivot joint according to the invention with a displacement-limited roller, 
         FIG. 15  shows a schematic representation of a second preferred development of a constant velocity pivot joint according to the invention with a displacement-limited roller, 
         FIG. 16  shows a schematic representation of a first embodiment of a constant velocity pivot joint according to the invention with a tilt-limited roller, and 
         FIG. 17  shows a schematic representation of a second embodiment of a constant velocity pivot joint according to the invention with a tilt-limited roller. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Various embodiments of a constant velocity pivot joint according to the invention are described in conjunction with  FIGS. 1 to 17 . In this case,  FIGS. 1 to 3  show the constant velocity pivot joint known from DE 102 06 733 A1, the structure of which is substantially identical—apart from the rollers of the joint—to that of the constant velocity pivot joint known from DE 103 25 116 A1 and of the constant velocity pivot joint according to the invention. 
       FIG. 1  shows an exploded perspective view of a known constant velocity pivot joint  10  with an outer joint part  12  and an inner joint part  14  configured as a tripod star. The outer joint part is shown separately in  FIG. 2 , whereas the tripod star  14  is shown separately in  FIG. 4 . A set of three elongate and axially extending guideways or running surfaces  16  are circumferentially formed within the cavity of the outer joint part  12 .  FIG. 3  shows a partial section of the outer joint part  12 , the section extending in the longitudinal direction along the part. As can best be seen in  FIG. 2 , each guideway  16  comprises opposite inner surfaces or sides  18  and  20  and an outer end side or end face  22 . In this exemplary embodiment, the inner sides  18  and  20  are configured so as to have a spherical or concave contour. The end face  22  is configured so as to have an upwardly protruding middle section  24 . Due to the fact that the middle section  24  of the end face  22  protrudes upwardly, a shoulder surface  26  is advantageously formed which bears the top side of a roller  28  and limits a displacement of the roller  28  within the guideway  16 . Furthermore, the upwardly protruding middle section  24  provides a lubricant channel for an optimum distribution of lubricating grease to the guideways  16  and bears surfaces in order to reduce the sliding and rolling contact friction, thereby reducing the joint plunger effect. 
     As is shown in  FIGS. 4 and 5 , the tripod star  14  comprises three axle pins  30  circumferentially disposed about a spider body  32 . In the embodiment shown, each of the axle pins  30  forms on its free end a pivot pin  34  with a partially spherical roller bearing surface  44 . As is explained below, the pivot pins  34  are disposed or designed so as to fit into a single-part inner ring  48  of a roller  28 . A set of cut-off or flattened surface sections  36  are formed in opposite areas of the outer pivot pin diameter in such a way that a lubricant channel is provided for better lubrication. Furthermore, the flattened surface sections  36  are configured such that it is possible to mount the single-part inner ring  48  on the pivot pin  34 . This only requires that the inner ring  48  be tilted suitably relative to the pivot pin  34 , as will be explained below in more detail. 
     As is best apparent from  FIG. 5 , the outer shape of the pivot pin  34  is formed by a spherical central area  38  with a radius r 2 . Upper and lower curved areas  40  extend up to the top side and down to the neck of the axle pin  30  with a smaller radius r 3 . As is shown in  FIG. 3 , the shape of the pivot pins  34  permits a tilting movement of the tripod star  14  relative to an inner ring of the roller  28  if the constant velocity pivot joint  1  is displaced in an articulated manner. In this case, the roller  28  remains in a suitable parallel orientation relative to the side walls  18 ,  20  of the guideways  16 . 
       FIGS. 9 and 10  show a sectional view of the roller  28  of the constant velocity pivot joint  1  according to the invention. The roller comprises an outer ring  42  and an inner ring  48  between which a set of rolling members  46 , such as rollers of a needle bearing, is disposed. In this case, the inner ring  48  forms two radially extending lower and upper flanges  50  and  52 , which form an axial guide for the rolling members  46 . This axial guide fixes the position of the rolling members  46  relative to the inner ring  48  in the axial direction, with the inner ring  48  bearing or supporting the rolling members  46  on its outer side. 
     As is shown in  FIGS. 9 and 10 , the thickness of the outer ring  42  is selected such that it exceeds the thickness of the inner ring  48  and the length of the rolling members  46 . The outer ring  42  has a significantly greater thickness than the inner ring  48  in order to obtain a sufficient axial displacement path of the bearing rings relative to each other, with the inner ring  48  being supported on the rolling members  46  over its entire width within the guideway, independent from the fixed position of the outer ring  42 . According to the invention, the inner ring  48  is movable so that the inner ring  48  remains suitably positioned relative to the pivot pin  34  when the pivot pin  34  pivots therein. 
     Reference is now made again to  FIGS. 7 and 8  in order to describe the mounting of a roller  28  on a pivot pin  34 . A roller  28  is mounted on a roller bearing surface  44  of a pivot pin  34  of the tripod star  14  by aligning one side of the inner ring  48  with the outer side of the roller bearing surface  44  under a certain angle, and then by moving the opposite side of the inner ring  48  over the roller bearing surface  44  until the section with the smallest diameter of the inner ring  48  slips over the section with the largest diameter of the roller bearing surface  44 . In other words, when the inner ring  48  is positioned at a certain angle, the opposite side exposes the outer radius of the pivot pin  34  and permits the entire inner ring  48  to be pushed or to slip over the pivot pin  34 . After the inner ring  48  has been pushed over the section with the largest diameter of the pivot pin  34 , the roller  28  is newly oriented in such a way that the inner ring  48  is not angled anymore at the special angle, with the curvature of the inner ring  48  leading to the roller  48  being retained on the pivot pin  34 . 
       FIG. 6  shows the tripod star  14  of the constant velocity pivot joint  1  according to the invention in a top view with a roller  28  mounted on a pivot pin  34 . This tripod star  14  with the roller  28  placed thereon is once again shown in a sectional view in  FIG. 7 . It is clearly apparent from this sectional view how the inner roller surface  54  of the roller  28  grasps around the roller bearing surface  44  of the pivot pin, with a limited tilting movement of the roller  28  relative to the axis of symmetry of the pivot pin  34  being possible.  FIG. 8  once again shows a section through the axle pin  34  with the roller  28  from  FIG. 6  placed thereon, the section having been carried out along a sectional plane extending through the section line A-A and standing perpendicularly on the paper plane. Once again, the radius r 2  of the spherical central areas  36  of the ball pins  34  which form the roller bearing surfaces  44  can be seen. The lubricant channel between the pivot pin  34  and the roller  28  formed by the flattened surface sections  36  is also visible. 
       FIG. 7  shows the mounted roller in its middle operating position, i.e. the inner ring  48  and the outer ring  42  lie one above the other in a substantially centered manner. According to the invention, the mounted roller is now also secured against falling apart even at maximum relative displacement of the inner ring  48  and the outer ring  42 . To this end, the outer ring  42  forms, at the side thereof opposite to the lower flange  50  of the inner ring  48 , a stop  10 , as can be seen from  FIG. 10 . This forms a resting portion for the rolling members  46  of the roller  26  against which they, in a first extreme position of the roller  26  apparent from  FIG. 11 , come to rest, thus preventing a further axial relative displacement of the bearing rings  42 ,  48  of the roller  26 . The mechanical contact point resulting therefrom is designated by the arrow in  FIG. 11 . The stop  10  secures the roller  28  against falling apart both during the final assembly of the constant velocity pivot joint  1  according to the invention as well as during its operation in an axial displacement direction. 
     In the assembled state of the constant velocity pivot joint  1  according to the invention, it, as well as the roller  28 , is secured against falling apart also in the other axial displacement direction of the bearing rings  42 ,  48 . This is done by means of a mechanical support of the outer ring  42  on the tripod star  14  as it can be seen in  FIG. 12 , marked by an arrow. Such a mechanical support can be formed by selecting suitable dimensions for the outer ring  42  and the tripod star  14 . 
     The outer diameter of the inner ring  48  including the flanges  50 ,  52 , which are approximately of equal length, is smaller than the inner diameter of the outer ring  42  including the stop  10 , as can be seen in  FIG. 10 . A gap having the gap width d remains between the lower flange  50  and the stop  10 . The gap width d is dimensioned such that the inner ring  48  without the inserted rolling members  46  can be freely passed through the outer ring  42  of the roller  28 . A direct mechanical support of the bearing rings  42 ,  48  on each other, which would lead to a high degree of wear due to the relative rotational movement of the bearing rings  42 ,  48 , is thus avoided. In the exemplary embodiment shown, the upper flange  50  and the lower flange  52  therefore serve exclusively for guiding the rolling members  46 . Rather, the support takes place indirectly through the quickly rotating rolling members  46 , whereby the friction and thus the wear can be significantly reduced. 
     In order to mount the roller  28  in accordance with the above exemplary embodiment, it has proved advantageous if the rolling member raceway of the inner ring  48  is filled with grease, into which the rolling members  46  are then pressed. Due to the grease filling, the rolling members  46  adhere on the inner ring  48  so that a simpler joining of the roller  28  is possible. 
     As is best apparent from  FIGS. 8 and 9 , each roller  28  uses a concave, i.e. spherical, inner rolling member surface  54  on the inner ring  48  in order to facilitate grasping with the outer spherical contour of the pivot pin  34 , i.e. the roller bearing surface  44 . The concave inner surface of the inner ring  48  serves for distributing the contact points between the pivot pin  34  and the inner ring  48  uniformly when the pivot pin  34  pivots in the roller  28 . In particular, the ball/ball contact surface of the pivot pin  34  with the surface of the inner ring  48  serves for reducing Hertzian stresses by distributing the force over a ball/cylinder contact surface arrangement. This in turn advantageously reduces the friction and the potential shaking of the joint during operation of the vehicle. 
     The outer rolling member surface  56  of the outer ring  42  has the shape of a cut-off ball with substantially the same diameter as the cylindrical side walls  18 ,  20  of the guideways  16  of the outer joint part  12  in order to produce a single continuous contact area between the two surfaces. The ball/ball contact surface of the outer ring  42  with the opposite side walls  18 ,  20  of the guideways  16  distributes the force more uniformly while reducing contact stresses occurring during the operation of the joint. 
       FIG. 13  illustrates the problems by way of example which result during the assembly of the outer joint part  12  and the inner joint part  14  of a constant velocity pivot joint according to the invention, if it takes place, for example, in a motor vehicle assembly line. During assembly, the half shaft, which is provided with splines and with which the outer joint  12  is connected, is generally mounted in the gear unit of the motor vehicle. Then, the inner joint  14  of the constant velocity pivot joint according to the invention, i.e. the tripod star  32  with the rollers placed on the pins  34 , is inserted into the outer joint  12 . However, this generally gives rise to the problem of the outer ring  42  of the roller being displaced relative to the inner ring  48  under the influence of the force of gravity, as is shown in  FIG. 13 . Since the position of three rollers  28  has to be controlled simultaneously in such a way that they can be inserted into the raceways  16  of the outer joint  12 , this is a task that a mechanic can hardly cope with in practice. 
       FIG. 14  now shows a preferred embodiment of the pivot joint  1  according to the invention in which the assembly is simplified significantly. In contrast to the situation shown in  FIG. 13 , in which the outer ring  42  of the roller  28  only comprises one displacement stop  10  oriented towards the center of the tripod star  32 , the outer ring  42  in this case comprises on its radially outer end on its inner raceway an annular groove  9  into which a spring ring  11  is inserted. This spring ring  11  is inserted after the roller  28  consisting of the inner ring  48 , the outer ring  42  and the rolling members  46  was assembled, inserted into the annular groove  9 , and secures the roller  28  against falling apart. Moreover, it becomes clear from  FIG. 14  that the second displacement stop  11  significantly limits the axial displacement of the outer ring  42  relative to the inner ring  48  under the influence of the weight, so that only small positional corrections of the outer ring  42  are required so that the roller  28  can be inserted into the raceway  16  of the outer joint. Moreover, it is clearly apparent from  FIG. 14  that the distance d between the displacement stops  11  and  12  is significantly larger than the length L of the roller members  46 ; preferably, the distance d is greater than the length L by 25 to 100%, in the present case by about 50%. 
     Instead of as the above-mentioned spring ring, which is inserted into an annular groove  9 , the second displacement stop  11  can also be designed as a simple disk which is supported on an inner shoulder. On the outside, the disk is mechanically fixed on the outer ring  42  by the latter being beaded or caulked. 
       FIG. 15  shows an alternative embodiment of a constant velocity pivot joint according to the invention which differs from the embodiment of  FIG. 14  only in the relative arrangement of the first and second displacement stops  10 ,  11 . It is apparent from  FIG. 15  that the outer displacement stop  11  is now formed as an annular offset configured integrally with the outer ring of the bearing  42 . In the exemplary embodiment according to  FIG. 14 , the inner displacement stop  10  is in contrast configured as a spring ring which was inserted into the groove  9  subsequent to an assembly of the roller  28 , thus securing the roller  28  against falling apart. 
       FIG. 16  now shows a preferred development of the constant velocity pivot joint according to the  FIG. 14  or  15 , which, in addition to the limitation of the axial displaceability of the outer ring  42  of the roller  28  relative to the inner ring  48  by means of two displacement stops  10  and  11 , which in this case are integrally formed with the outer ring  42 , comprises a means which detachably fixes the inner ring  48  of the roller  28  in a defined angular position relative to the pin axis Z of the pin  34 . This fixation primarily serves to prevent the tilting of the rollers  28  on the pins  34  of the tripod star  32  when the inner joint  14  of the constant velocity pivot joint  1  according to the invention is mounted in the outer joint  12 . In the embodiment of the constant velocity pivot joint shown in  FIG. 16 , point-shaped deformations were produced for this purpose, for example by means of mechanical center-punching, i.e. local plastic deformation of the roller bearing surface  44 , on the outer end of the roller bearing surfaces  44  on each roller bearing surface  44  after the roller  28  has been placed on the pin  34 . These point-shaped deformations  100  constitute a mechanical barrier for the inner ring  48  of the roller  28  against tilting from the rest position. In the exemplary embodiment according to  FIG. 16 , the axis of rotation R of the roller  28  just about coincides with the pin axis Z in the rest position. The point-shaped deformation  100  prevents the tilting of the roller  28  in the manner indicated schematically in  FIG. 16  by the tilted axis of rotation R. Since the angular position of the roller  28  on the pin  34  of the tripod star  32  is fixed by the point-shaped deformations  100 , a particularly simple assembly of the inner joint part  14  in the outer joint part  12  is possible. For this purpose, the rest position of the roller  28  on the pin  34  is advantageously set in such a way that the orientation of the roller  28  on the pin  34  substantially corresponds to the alignment of the raceways  14  aligned in the circumferential direction in the outer joint part. After the inner joint part  14  of the constant velocity pivot joint  1  according to the invention has been inserted into the outer joint  12 , by tilting the axis of rotation of the inner joint part relative to the axis of rotation of the outer joint part  12 , the mechanical barrier against tilting of the rollers  28  on the pins  34  can be overcome by causing a new plastic deformation of the roller bearing surface  44  in the area of the bottom-shaped deformation  100 . Thereafter, a tilting of the rollers  28  on the pin  34  is possible practically without force. 
     Finally,  FIG. 17  shows another advantageous embodiment of a constant velocity pivot joint according to the invention with a tilting protection of the type according to the invention for the rollers  28  mounted on the pin  34  of the tripod star  32 . Instead of a point-shaped mechanical deformation  100  on the roller bearing surface  44  of the pins  34 , the exemplary embodiment according to  FIG. 17  comprises an annular groove at the inner end of the spherical inner roller surface  54 . A spring ring  104 , which cooperates with an edge in the surface of the pin  34  that is not shown in more detail in  FIG. 17 , is inserted into this annular groove  102 . When the spring ring  104  comes to rest against this edge, it thus defines the rest position of the inner ring  48  placed on the pin  34 . In order to tilt the axis of rotation R of the roller  28  from this rest position, an elastic deformation of the spring ring  104  inserted into the annular groove  102  is required so that a defined tilting moment has to be applied to the axis of rotation R of the roller  28  in order to tilt it from the rest position indicated in  FIG. 17 . It is possible in principle to leave the spring ring  104  in place after the final assembly of the inner joint part  14  in the outer joint part  12  if no tilting moments have to be overcome in this case that are too large. However, the wear that occurs can be minimized by removing the spring ring  104  from the annular groove  102  after the constant velocity pivot joint  1  according to the invention has been assembled on the motor vehicle assembly line. 
     What is not shown in the Figures is another possible improvement of the constant velocity pivot joint known from DE 103 25 116 A1. For it is possible to provide, at the open end of the outer joint part  12 , inclined portions on the guideways  16 , which make it easier to thread in the rollers  28  of the inner joint part  14  during the assembly, in that they catch the outer rings even at a certain axial displacement of the outer rings  42  relative to the inner rings and guide them into the guideways  16 . 
     Various exemplary embodiments of the invention were explained above. However, the invention is not limited thereto, but is open to numerous alterations and modifications, in particular in accordance with the equivalent embodiment according to claim  7 . 
     
       
         
           
               
             
               
                   
               
               
                 Reference numerals 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                 1 
                 Constant velocity pivot joint 
               
               
                 9 
                 Annular groove 
               
               
                 10 
                 Inner displacement stop 
               
               
                 11 
                 Outer displacement stop 
               
               
                 12 
                 Outer joint part 
               
               
                 14 
                 Inner joint part 
               
               
                 16 
                 Guideway 
               
               
                 18 
                 Side wall 
               
               
                 20 
                 Side wall 
               
               
                 22 
                 End face 
               
               
                 24 
                 Middle section 
               
               
                 26 
                 Shoulder surface 
               
               
                 28 
                 Roller 
               
               
                 28 
                 Roller 
               
               
                 30 
                 Axle pin 
               
               
                 32 
                 Spider body 
               
               
                 34 
                 Pivot pin 
               
               
                 36 
                 Surface section 
               
               
                 38 
                 Spherical central 
               
               
                   
                 area 
               
               
                 40 
                 Upper/lower curved 
               
               
                   
                 area 
               
               
                 42 
                 Outer ring 
               
               
                 44 
                 Roller bearing 
               
               
                   
                 surface 
               
               
                 46 
                 Rolling member 
               
               
                 48 
                 Inner ring 
               
               
                 50 
                 Lower flange 
               
               
                 52 
                 Upper flange 
               
               
                 54 
                 Inner roller surface 
               
               
                 56 
                 Outer roller surface 
               
               
                 100 
                 Point-shaped 
               
               
                   
                 deformation 
               
               
                 102 
                 Annular groove 
               
               
                 104 
                 Spring ring