Tripod joint and motor vehicle

Abstract

To provide a tripod type joint that reduces ACFG force, and secures mountability of rotating bodies on trunnions.SOLUTION: A tripod type joint (1) comprises an outside joint portion (2) and an inside joint portion (7). The outside joint portion (2) comprises a first longitudinal axis (3) and a cavity (4) comprising an opening end, and three concave parts (6) are formed in the outside joint portion (2). The inside joint portion (7) comprises a second longitudinal axis (8) and a central body (9), and three trunnions (10) comprising trunnion axes (11) are formed. Rotating bodies (12) are arranged on the respective trunnions (10) and comprise outer rings (13) and inner rings (15) capable of rotating around common rotation axes (14), and bearing bodies (16) arranged between the outer rings (13) and the inner rings (15). The rotating bodies (12) are movably housed in the concave parts (6), and can move along the first longitudinal axis (3).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a tripod joint having an outer joint portion and an inner joint portion having a central body with three trunnions formed integrally therewith. A rotating body is disposed on each trunnion. Further, the present invention relates to an automobile equipped with such a tripod joint.

Background Art

[0002] This type of tripod joint usually includes an outer joint portion, which has a first longitudinal axis and a cavity extending parallel to the first longitudinal axis and having an open end, and three recesses extending parallel to the first longitudinal axis are formed in the outer joint portion. Further, the tripod joint includes an inner joint portion having a second longitudinal axis, the inner joint portion has at least one central body, and three trunnions having trunnion axes extending radially from the second longitudinal axis are formed on the central body. A rotating body is disposed on each trunnion, and the rotating body has at least one outer ring, an inner ring rotatable about a common axis of rotation with respect to the outer ring, and a support body disposed between the outer ring and the inner ring. The rotating bodies are each movably received in the recesses and can move along the first longitudinal axis.

[0003] To assemble the trunnion and the rotating body disposed on the trunnion into the tripod joint, the inner joint portion can be inserted into the cavity of the outer joint portion through the open end.

[0004] The central body itself can serve as a shaft or can be connected to a shaft via a spline or the like.

[0005] The inner joint part can be displaced along the first longitudinal axis with respect to the outer joint part and can be deflected by a certain deflection angle with respect to the outer joint part. This deflection angle is the minimum angle between the first longitudinal axis and the second longitudinal axis.

[0006] Tripod joints have been manufactured and sold by the applicant for a certain period under the name of, for example, AAR tripod joints. These tripod joints are used for the side shafts of automobiles and, in particular, serve as a drive connection between the differential gear and the drive wheel. On the wheel side, a so-called constant velocity ball fixed joint is usually used, and the AAR tripod joint mentioned here is used as a sliding joint in the differential gear. The AAR tripod joint is designed in particular for deflection angles on the order of 23 to 26° (hereinafter).

[0007] In the AARi tripod joint, which is a sub-type of the AAR tripod joint, the inner ring is cylindrical towards the trunnion and is fixed to the outer ring by a retaining ring in the direction along the rotation axis.

[0008] The trunnion contacts the inner ring of the support body or the rotating body through a so-called sliding surface (contact surface). Each sliding surface is designed in particular in the shape of a spherical table. These sliding surfaces are aligned circumferentially around the second longitudinal axis, and the torque acting around the plurality of longitudinal axes of the joint is transmitted from the trunnion through each sliding surface to the rotating body and then from the rotating body to the recess (or vice versa).

[0009] During the operation of an automobile, various states may occur in the side shaft, for example. This side shaft extends substantially parallel to the vehicle axle of the automobile, and the wheel can be driven by a drive unit via this side shaft. In the traction (pull) mode, the wheel is driven by the drive unit. In the push mode, the automobile is pulled by the mass of the automobile having momentum. Regarding the tripod joint disposed on the side shaft, the contact between the sliding surface of the rotating body and the trunnion is different in each predetermined state.

[0010] For example, when the automobile is driving forward, the rotation direction of the side shaft is constant. When changing between the push mode and the traction mode, the contact between the sliding surface and the trunnion changes. Even when the automobile changes its traveling direction (from forward to backward), the contact between the sliding surface and the trunnion changes to the opposite side of the trunnion when viewed in the circumferential direction.

[0011] In the traction mode of the automobile, that is, when the automobile is being driven by the drive unit, the trunnion contacts one sliding surface of the rotating body, and the rotating body contacts particularly one side of the concave portion. In the case of the push mode or the coast mode (both are referred to as the coasting mode) of the automobile, that is, when the driving torque from the wheel is introduced and the drive unit is further connected (push mode) or disconnected (coast mode), the trunnion contacts the other sliding surface of the rotating body, and the rotating body contacts particularly the opposite side of the concave portion. In the push mode and the coast mode, the direction of the introduced torque and the rotation direction of the joint are opposite to each other, and they are in the same direction in the traction mode.

[0012] In order to achieve particularly advantageous guiding characteristics, an offset can be provided between the first pitch circle radius of the sliding surface of each trunnion (i.e., the inner joint portion) and the second pitch circle radius of each concave portion (i.e., the outer joint portion).

[0013] The pitch circle radius of each trunnion or the inner joint part is the so-called effective radius. This is defined for the case of an extended joint, i.e., when each longitudinal axis is arranged coaxially. The effective radius determines the resulting lever arm when torque is transmitted. Therefore, the pitch circle radius of each trunnion or the inner joint part is the radius starting from the second longitudinal axis of the inner joint part. For example, when the joint is extended, the center points of the spherical sliding surfaces of each trunnion are arranged on this radius.

[0014] Here, the pitch circle radius of the outer joint part or each recess is also the so-called effective radius. This is defined for the case of an extended joint, i.e., when each longitudinal axis is arranged coaxially. The effective radius determines the resulting lever arm when torque is transmitted.

[0015] The definition of the pitch circle radius (also known as Pitch Circle Radius (PCR)) is basically known, especially for tripod joints.

[0016] Therefore, the offset of each pitch circle radius is the difference between these pitch circle radii.

[0017] Also, the characteristics of the tripod joint are determined in particular by the so-called ACFG value (Axial Cyclic Force Generation, the unwanted axial force generated by the joint). This value is given as the root mean square value of the force, and the unit is Newton root mean square [Nrms]. The value varies as a function of the deflection angle of the joint, and thus the transition / curve of the value can be defined or determined as a function of the deflection angle for each joint. The range in which the joint is used is thus limited by the maximum deflection angle. At this maximum deflection angle, the ACFG value does not exceed an amount considered acceptable.

[0018] Various designs of each rotating body and each trunnion are known. In the first embodiment in Patent Document 1, each support body is arranged in the installation space of the outer ring. The inner ring is displaceable along a common rotation axis with respect to the outer ring and each support body. The inner ring is locally fixed to the trunnion by two stops, that is, the inner ring is pivotable with respect to the trunnion axis but cannot be displaced along the trunnion axis with respect to the trunnion. In order to attach a rotating body on the trunnion, it is necessary to pivot at least the inner ring with respect to the trunnion axis to such an extent that the inner ring can be pressed against the trunnion through the stops. However, the need for pivoting means that it is necessary to realize a narrowing of the transition area between the trunnion and the central body into which the inner ring can enter during assembly. Narrowing the transition area in this way can, for example, affect the applicable range of the joint with respect to the transmissible torque. Furthermore, by arranging the stops closer to the central body, the maximum possible deflection angle is limited. That is, the stops and the central body collide.

[0019] In a similar design of the joint according to Patent Document 2, the inner ring is narrower, but each support body is partially exposed during the operation of the joint, is not covered by the inner ring, and does not contact the inner ring.

[0020] In the second embodiment according to Patent Document 3, the inner ring is fixed to the trunnion by a single stop, that is, only the displacement of the inner ring in the direction of the second longitudinal axis is restricted. On the other hand, a stop is provided between the inner ring and each recess, which increases the axial force due to the friction generated as a result of the sliding movement.

[0021] In the third embodiment according to Patent Document 4, each support is arranged in the installation space of the inner ring. The inner ring, together with each support, is displaceable relative to the outer ring along a common rotation axis. The inner ring is fixed to the trunnion by two stops, that is, the inner ring is pivotable relative to the trunnion axis, but can only displace a small distance along the trunnion axis relative to the trunnion. In addition to the disadvantages described with reference to the first embodiment, it may also move between the stops and thus come into contact with the two stops alternately.

[0022] In the fourth embodiment according to Patent Document 5, the inner ring is fixed to the outer ring, for example, via a retaining ring, so that it is impossible for the inner ring to displace along the rotation axis relative to the outer ring. No stop is provided between the trunnion and the inner ring. On the other hand, since the inner ring contacts the inside of the two retaining rings in the form of a brake disc, an ACFG problem may occur in the traction mode and the push mode.

Prior Art Documents

Patent Documents

[0023]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0024] Therefore, the present invention is based on an approach that at least partially solves the problems described with reference to the prior art.

[0025] In particular, a tripod joint is proposed, by which the ACFG force can be reduced, and the mountability of the rotating body onto each trunnion is ensured. For this purpose, the stopper should be designed in a more advantageous manner. In addition, the tripod joint should be designed to be more durable.

Means for Solving the Problems

[0026] These problems are solved by the tripod joint according to the features of claim 1. The dependent claims show further advantageous embodiments. Note that the features individually listed in the dependent claims can be combined with each other in any technically beneficial manner, and further embodiments of the present invention can be defined. In addition, the features shown in each claim are described and explained in more detail herein, thereby describing further preferred embodiments of the present invention.

[0027] This problem is solved by the following tripod joint. This tripod joint includes an outer joint portion and an inner joint portion. The outer joint portion has a first longitudinal axis and a cavity that extends parallel to the first longitudinal axis and has an open end. Three recesses extending parallel to the first longitudinal axis are formed in the outer joint portion. The inner joint portion has a second longitudinal axis. The inner joint portion has at least one central body, and three trunnions having trunnion axes extending radially from the second longitudinal axis are formed on the central body. A rotating body is disposed on each trunnion, and the rotating body has at least one outer ring and one inner ring that are rotatable around a common rotation axis, and a bearing body disposed between the outer ring and the inner ring.

[0028] The rotors are each received in respective recesses and are movable along a first longitudinal axis. In the intended operation of the tripod joint, one of the inner and outer rings is displaceable along the axis of rotation relative to the other of the inner and outer rings, together with the support body. The outer ring provides a first stop for the inner ring, and this first stop limits the displacement path L of the inner ring relative to the outer ring in a direction away from the second longitudinal axis along the axis of rotation. At least when the axis of rotation and the trunnion axis are coaxially arranged, the inner ring provides a second stop for the trunnion, and this second stop limits the displacement of the inner ring in a direction towards the second longitudinal axis along the trunnion axis. In the intended operation, the displacement of the inner ring relative to the trunnion in a direction away from the second longitudinal axis along the trunnion axis is not restricted, i.e., it is restricted only by the first stop.

[0029] The rotor particularly has an outer ring and an inner ring, and the outer ring and the inner ring are rotatable relative to each other. To this end, a support body (rolling elements, for example needle rolling elements) is arranged between the inner ring and the outer ring in a known manner. These support bodies are arranged in the installation space of the inner ring or the outer ring. A large number of these support bodies are arranged circumferentially around the axis of rotation.

[0030] When the inner ring rotates relative to the outer ring, the rotor can roll along a recess or a track in the outer joint portion, whereby the inner joint portion is displaceable along the first longitudinal axis relative to the outer joint portion.

[0031] When the inner joint portion is deflected, the rotor is further guided via the track, whereby at least the trunnion pivots relative to the rotor.

[0032] In particular, the rotor is guided by the recess in such a manner that it is impossible to pivot relative to the recess.

[0033] As another aspect, when the inner joint portion is deflected, the rotor also pivots relative to the recess.

[0034] In addition to rotating relative to each other, the inner ring and the outer ring are displaced relative to each other along a common axis of rotation.

[0035] The intended operation of a tripod joint (also called a joint) includes the inner joint portion and the outer joint portion being arranged relative to each other for a particular application. For example, each rotating body is disposed in a recess, and the joint operates only within a deflection angle within a predetermined range, for example, between 0 and 30°, or between 0 and 26°. Further, a torque considered acceptable by the joint is transmitted between the outer joint portion and the inner joint portion, and the rotating body is displaced to some extent along a first longitudinal axis.

[0036] Unintended operations include, for example, assembling the joint or assembling joint portions such as disposing the rotating body 12 on the trunnion 10.

[0037] In particular, the outer ring provides a first stop (exactly one or only one) for the inner ring, and this first stop limits the displacement path L of the inner ring relative to the outer ring along the axis of rotation and away from the second longitudinal axis. In particular, this first stop is formed by a projection of the outer ring or the inner ring, and the inner ring or the outer ring abuts against this projection when the inner ring has advanced along the displacement path L. Accordingly, the inner ring can move along this direction. Accordingly, the inner ring can be displaced only along this direction, that is, along the axis of rotation (particularly in a direction away from the second longitudinal axis), up to the point where the stop surfaces contact each other. In particular, during the intended operation, in the opposite direction along the axis of rotation (i.e., the direction towards the second longitudinal axis), the inner ring is displaceable infinitely at least relative to the outer ring. However, it is not possible relative to the trunnion.

[0038] The starting point or zero point of the displacement path is, in particular, the position of the inner ring when the joint is not deflected (i.e., the longitudinal axes of the outer joint part and the inner joint part are coaxially arranged), starting from PCR1, i.e., starting from the PCR of the inner joint part. From here, at least most of the movement of the inner joint part (corresponding to the ROM, i.e., the displacement path of each trunnion starting from PCR1 along the axis of rotation and away from the second longitudinal axis) becomes possible only along the displacement path towards the first stop. If the inner ring should contact the outer ring at the first stop even before reaching the maximum deflection angle, in particular, during (only) the assembly of the joint, any further movement of the inner joint part up to the maximum deflection angle that is reached can be absorbed by the play of the corresponding rotors in each recess of the outer joint part.

[0039] At least when the axis of rotation and the trunnion axis are coaxially arranged, the inner ring forms a (strictly one or only one) second stop for the trunnion. The second stop limits the displacement of the inner ring along the trunnion axis in the direction towards the second longitudinal axis. In the intended operation, i.e., when the inner joint part is arranged together with the outer joint part to form a tripod joint, the displacement of the inner ring relative to the trunnion along the trunnion axis and away from the second longitudinal axis is not restricted, i.e., it is restricted only by the first stop. In particular, the outer ring is supported by the recesses, whereby the first stop prevents further displacement of the inner joint part.

[0040] In the coasting mode (push mode and sail mode), in particular, the displacement of the inner ring can be restricted by the first stop.

[0041] In the traction mode, in particular, the displacement of the inner ring can be controlled using the second stop.

[0042] In particular, the first stop is arranged along the axis of rotation on the first side of the support facing towards the second longitudinal axis or on the second side of the support facing away from the second longitudinal axis.

[0043] When the first stop is arranged along the axis of rotation on the first side of the support body facing the second longitudinal axis, this first stop can in particular be formed by a projection of the outer ring, which projection extends away from the axis of rotation along the radial direction and thus extends at least partially beyond the inner ring.

[0044] When the first stop is arranged along the axis of rotation on the second side of the support body facing away from the second longitudinal axis, this first stop can in particular be formed by a projection of the outer ring, which extends inwards towards the axis of rotation along the radial direction and thus extends at least partially beyond the inner ring.

[0045] In particular, for the displacement path L, L>0.7×ROM is applicable, and for ROM, ROM=0.5×PCR1×(1 - cos(beta max )) is applicable, ROM is the displacement path of the trunnion along the axis of rotation starting from PCR1 and in the direction away from the second longitudinal axis, PCR1 is the pitch circle radius of the inner joint part, beta max is the maximum deflection angle of the tripod joint.

[0046] ROM or "the movement of the tripod peg outwards in the radial direction" (i.e., the displacement of the trunnion outwards in the radial direction) refers to the displacement of PCR1 (pitch circle radius) of the inner joint part between the first state and the second state, where the first state is the state in which the longitudinal axes are coaxial with each other, and the second state is the state in which the longitudinal axes are deflected from each other to the maximum extent (the state in which the maximum deflection angle is achieved / exists).

[0047] In particular, the inner ring is in contact via a second stop and is displaced together with the trunnion. The displacement of the inner ring relative to the outer ring should only be achievable over the (possible) displacement path L, i.e., when the trunnion is displaced to the maximum extent (i.e., by only the ROM), the inner ring should form the first stop against the outer ring. In this case, L > 1.0 × ROM will apply. At extreme deflection angles (i.e., deflection angles close to the maximum deflection angle), it is applicable that these deflection angles usually occur without load. In these cases, the displacement path L can be made somewhat smaller than the ROM, and in particular, L > 0.7 × ROM can also be set.

[0048] In particular, each of the bearing bodies has a circumferential surface that extends over at least a length portion along the rotation axis, and this length portion is for contacting the contact surface of the inner ring or the outer ring. The contact surface is displaceable along the rotation axis for each bearing body, and during the intended operation, the circumferential surface is always in contact with the entire length portion of the contact surface at any time.

[0049] In particular, in the design of the inner ring, the outer ring, and each bearing body, all possible positions that the inner ring can take relative to the outer ring during the intended operation are considered. Thereby, during the operation of the tripod joint, it is possible to prevent each bearing body from being only partially covered by the (inner or outer) ring displaceable relative to the bearing body.

[0050] On the other hand, during the intended operation, in at least individual arrangements of the tripod joint, it is also possible for the circumferential surface of each bearing body to contact the contact surfaces of the outer ring and the inner ring respectively only over a part of the length portion. However, in particular, only a part of the length portion of the circumferential surface of each bearing body does not contact. In particular, this non - contacting part of the length portion is arranged only directly adjacent to the second side of each bearing body facing away from the second longitudinal axis. However, the non - contacting length portion is in particular at most 50%, in particular at most 25%, preferably at most 10% of the length portion of the circumferential surface that can contact.

[0051] This embodiment can be selected, for example, when a retaining ring is used to form the first stop, and the retaining ring also restricts the installation space for each support body in this case.

[0052] In particular, the inner ring forms a third stop for the trunnion, and the third stop restricts the displacement of the inner ring along the trunnion axis away from the second longitudinal axis. Only when attempting to remove the inner ring from the trunnion other than during the intended operation, the inner ring and the trunnion come into contact with each other via the third stop.

[0053] In particular, during the intended operation of the joint, the inner ring and the trunnion do not contact each other via the third stop (only contact via the second stop). The third stop enables a wide range of displacement of the inner ring with respect to the trunnion, and while the inner joint part is arranged within the outer joint part, the inner ring and the trunnion cannot contact each other via the third stop at all. In particular, the third stop functions only as a disassembly protection for the inner ring or the rotating body, whereby at least the inner ring can be held on the trunnion by the third stop.

[0054] In particular, the third stop is realized by a protrusion that extends from the inner ring towards the rotation axis 14.

[0055] In particular, the inner ring can be pressed against the trunnion by the third stop only in the pivoting state with respect to the trunnion axis. This pivoting state has a minimum angle of 5 - 20° (such as the measurable minimum angle, etc.) between the trunnion axis and the rotation axis, preferably at most 15°, particularly preferably at most 10°. This pivoting state has a minimum angle of at least 5° between the trunnion axis and the rotation axis, preferably at least 10°, or at least 15°.

[0056] Conversely, the inner ring can be held by the trunnion only when the angle between the trunnion axis and the rotation axis is less than 5°, particularly less than 10°, or less than 15°.

[0057] During torque transmission, the third stop does not contact the trunnion, so that the third stop can be designed with a correspondingly small size. In particular, the small size setting means that for placing the inner ring on the trunnion, only a small angle between the trunnion axis and the rotation axis is required. In particular, the small angle allows the transition area between the trunnion and the central body, through which the inner ring can enter during assembly, to be slightly narrowed. This transition area is thicker than that in known joints, but for example, the applicable range of the joint regarding the transmissible torque can be increased.

[0058] Regarding the design of the third stop as well, the joint corresponds to the definition of the proposed joint described at the beginning. According to this definition, during the intended operation, the displacement of the inner ring relative to the trunnion in the direction away from the second longitudinal axis along the trunnion axis is not restricted, that is, it is restricted only by the first stop. In particular, the third stop engages only when the rotating body is removed from the trunnion, that is, during the unintended operation of the joint.

[0059] In particular, the displacement of the trunnion relative to the inner ring is restricted by the first stop and the third stop, and the displacement is at least equal to RIM + ROM, that is, Displacement ≥ RIM + ROM For RIM and ROM, RIM = 1.5 × PCR1 × (1 - cos(beta max )) and ROM = 0.5 × PCR1 × (1 - cos(beta max ) are applicable, RIM is the displacement path RIM of the trunnion in the direction towards the second longitudinal axis along the rotation axis starting from PCR1, ROM is the displacement path ROM of the trunnion in the direction away from the second longitudinal axis along the rotation axis starting from PCR1, PCR1 is the pitch circle radius PCR1 of the inner joint part, beta max is the maximum deflection angle of the tripod joint.

[0060] Therefore, the third stop is arranged so that the above conditions are satisfied, that is, the (possible) displacement between the stops is greater than or equal to the sum of RIM and ROM.

[0061] RIM or "radial inward movement of the tripod peg" (i.e., displacement of the trunnion in the radial inward direction) refers to the displacement of the PCR1 (pitch circle radius) of the inner joint part between the first state and the second state. The first state is the state where the longitudinal axes are arranged coaxially with each other, and the second state is the state where the longitudinal axes are deflected from each other to the maximum extent (the state where the maximum deflection angle exists). The trunnion slides along the contact surface of the inner ring, and this contact surface is particularly cylindrical. This displacement RIM of the trunnion relative to the inner ring should be achievable, that is, the inner ring should not yet form the third stop for the trunnion.

[0062] In particular, when arranged coaxially with the rotation axis, the displacement of the inner ring along the trunnion axis away from the second longitudinal axis is not restricted even outside the intended use. In particular, the third stop is not provided.

[0063] In particular, the first stop is formed by the outer ring itself or by a stop ring arranged on the outer ring. The stop ring can be designed, for example, in the form of a so-called snap ring. The stop ring may be arranged in a circumferential groove on the outer ring and protrudes from the groove to contact the inner ring when the inner ring is displaced far enough away from the second longitudinal axis along the rotation axis.

[0064] Since the stop ring or the groove required for the stop ring requires additional structural space, the rotating body may have to be larger. However, when a stop ring is provided instead of forming a protrusion on the outer ring, the outer ring can be manufactured more economically.

[0065] In particular, the installation spaces for the respective bearing bodies on the outer ring are restricted by the retaining rings arranged on the outer ring. In particular, the installation spaces are restricted by one retaining ring each on both sides of each bearing body, that is, on the first side facing the second longitudinal axis and on the second side facing away from the second longitudinal axis.

[0066] In particular, the inner ring (15) has a stepped shape in a first cross-section (in a direction intersecting the second longitudinal axis), whereby the contact surface of the inner ring that cooperates with the bearing body is displaced inward along the rotation axis (towards the longitudinal axis) with respect to the end face of the inner ring. The end face of the inner ring is, in particular, the outermost surface of the inner ring (outer along the rotation axis, that is, in the direction away from the longitudinal axis).

[0067] In particular, the retaining ring (for at least one of the first stop and the third stop) has a stepped shape in cross-section, whereby the first stop of the retaining ring acting on the inner ring is displaced out of the groove of the outer ring along the rotation axis (outward, that is, in the direction away from the longitudinal axis), or is displaced from the fourth stop formed by the retaining ring towards each bearing body.

[0068] The stepped shape may have portions extending at right angles to each other or portions extending at an angle to each other.

[0069] In particular, the retaining ring has a groove, whereby it is elastically deformable to be fitted into the groove of the outer ring.

[0070] In particular, the second stop can be formed by a retaining ring arranged in a groove on the inner ring. The retaining ring used for the second stop particularly has a circular cross-section, but may also have a polygonal, square, trapezoidal, or stepped cross-section. The description regarding the shape of the retaining ring provided for the first or third stop is applied in the same way, in particular.

[0071] When a retaining ring is used for the second stop, the inner ring can be provided with a particularly cylindrical inner peripheral surface, in which case a groove for accommodating the retaining ring is provided in the inner peripheral surface.

[0072] In particular, in a cross-section extending in a direction intersecting the second longitudinal axis between the PCR1 of the inner joint portion and the central body, the inner joint portion has a minimum first wall thickness along the circumferential direction around the second longitudinal axis and a maximum second wall thickness on the radius of the PCR1. The ratio of the first wall thickness to the second wall thickness is at least 0.7, preferably at least 0.9, and more preferably at least 0.95. The PCR1 is the pitch circle radius of the inner joint portion.

[0073] The small angle between the rotation axis and the pivot axis is necessary for assembling the inner ring to the trunnion or removing the inner ring from the trunnion. This small angle makes it possible to slightly narrow the transition area between the trunnion and the central body in particular. The inner ring can enter this transition area during assembly or during the intended operation. This first wall thickness is thicker than that in a known joint, and for example, the applicable range of the joint regarding the transmissible torque can be increased.

[0074] In particular, the PCR1 of the inner joint portion is smaller than the PCR2 of the outer joint portion, and this PCR is the pitch circle radius.

[0075] In particular, the outer ring has a maximum diameter d in a cross-section including the rotation axis, and the outer peripheral surface of the outer ring is formed by a radius r, and 0.5 < 2×r / d < 1.5. When 2×r = d, the outer peripheral surface becomes a spherical surface.

[0076] For example, when the outer ring of the rotating body has a spherical outer contour on its outer peripheral surface, in the circumferential direction of the central body, the outer ring can be pivoted or swiveled around the central axis of the recess of the outer joint portion. The recess of the outer joint portion is correspondingly shaped, whereby the rotating body is not fixed in the circumferential direction of the outer joint portion. On both sides with respect to the central axis of the recess, it is pivotable, particularly within a range of 0 to 5°, and particularly within a range of 0 to 3°, in response to the resulting orbital motion. This pivoting is referred to as orbital motion or orbital angle. The central axis of the path is the axis of each recess of the outer joint portion, and as a result of the axial force of the outer joint portion, the rotating body can move along this axis.

[0077] In this case, between the trunnion and the inner ring, at least partial angle compensation of the orbital motion can also be performed. To do this, the peripheral surface of the trunnion must be convexly curved. The fact that this surface is convex means that the surface is designed according to a spherical frustum, a barrel-shaped section, a donut-shaped section, or a cylindrical section.

[0078] According to the embodiments of the tripod joint listed herein, in use, the inner joint portion can be deflected with respect to the outer joint portion, that is, the second longitudinal axis can be deflected with respect to the first longitudinal axis by at least 30°, particularly up to 32°, or up to 36°. This deflection is referred to as the deflection angle.

[0079] Furthermore, in this specification, an automobile equipped with at least one tripod joint according to the present invention is also claimed.

[0080] The indefinite articles ("a", "one") are not intended to be used as numerals, particularly in the claims and the descriptions that reproduce these claims, and should be understood as they are. Accordingly, the terms and components introduced correspondingly are intended to be understood as existing at least once, but particularly, they may also exist several times.

[0081] For the sake of avoiding ambiguity, it should be noted that the ordinal numbers (such as "first", "second", etc.) used in this specification are mainly provided (only) for the purpose of distinguishing several similar objects, numerical values, and steps. That is to say, in particular, these ordinal numbers do not necessarily define any dependency relationship or order among these objects, numerical values, and steps. When a dependency relationship or order is required, this will be specified in this specification or will become clear to those skilled in the art by examining the actually described configuration. When a dependency relationship or order is required, this will be specified in this specification or will become clear to those skilled in the art by examining the actually described configuration.

[0082] Hereinafter, with reference to the accompanying drawings, the present invention and the technical environment will be described in more detail. It should be noted that the present invention is not limited by the described design modification examples. In particular, it should be noted that the drawings and especially the illustrated ratios are merely schematic.

Brief Description of the Drawings

[0083]

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Figure 29

Mode for Carrying Out the Invention

[0084] FIG. 1 shows details of a (first) cross-section 33 of a first design modification example of a tripod joint 1. The tripod joint 1 includes an outer joint portion 2, and the outer joint portion 2 has a first longitudinal axis 3 and a cavity 4 that extends parallel to the first longitudinal axis 3 and has an open end 5. Three recesses 6 that extend parallel to the first longitudinal axis 3 are formed in the outer joint portion 2. Further, the tripod joint 1 includes an inner joint portion 7 having a second longitudinal axis 8. The inner joint portion 7 has a central body 9, and three trunnions 10 having trunnion axes 11 that extend radially from the second longitudinal axis 8 are formed on the central body. A rotating body 12 is disposed on each trunnion 10, and the rotating body 12 has at least one outer ring 13 and an inner ring 15 that are rotatable around a common rotation axis 14, and a support body 16 disposed between the outer ring 13 and the inner ring 15.

[0085] The rotors 12 are each received in the recess 6 and can move along the first longitudinal axis 3. In the intended operation of the tripod joint 1, the inner ring 15 is displaceable relative to the outer ring 13 and the support 16 along the axis of rotation 14. The outer ring 13 forms a first stop 17 for the inner ring 15, which restricts the displacement path L 18 of the inner ring 15 relative to the outer ring 13 along the axis of rotation 14 and away from the second longitudinal axis 8. Further, at least when the axis of rotation 14 and the trunnion axis 11 are coaxially arranged, the inner ring 15 forms a second stop 19 for the trunnion 10, which restricts the displacement of the inner ring 15 along the trunnion axis 11 and towards the second longitudinal axis 8. In the intended operation, the displacement of the inner ring 15 relative to the trunnion 10 along the trunnion axis 10 and away from the second longitudinal axis 8 is not restricted, i.e., it is restricted only by the first stop 17.

[0086] The rotor 12 has an outer ring 13 and an inner ring 15, and the outer ring 13 and the inner ring 15 are rotatable relative to each other. To this end, a support 16 (rolling elements, here needle rolling elements) is arranged between the inner ring 15 and the outer ring 13 in a known manner. These supports 16 are arranged in the installation space 32 of the outer ring 13. A plurality of these supports 16 are arranged around the axis of rotation 14 along the circumferential direction 34.

[0087] When the inner ring 15 rotates relative to the outer ring 13, the rotor 12 can roll along the recess 6 or the track in the outer joint part 2, whereby the inner joint part 7 is displaceable relative to the outer joint part 2 along the first longitudinal axis 3.

[0088] When the inner joint part 7 is deflected, the rotor 12 is further guided by the recess 6, whereby at least the trunnion 10 pivots relative to the rotor 12.

[0089] When the inner joint part 7 is deflected, the rotor 12 can also be pivoted to a small extent relative to the recess 6.

[0090] In addition to rotating relative to each other, the inner ring 15 and the outer ring 13 are displaced relative to each other along a common axis of rotation 14.

[0091] The intended operation of the tripod joint 1 includes the inner joint portion 7 and the outer joint portion 2 being arranged relative to each other for a specific application. For example, each rotating body 12 is arranged in the recess 6, and the joint 1 operates only within a deflection angle 24 within a predetermined range, for example, between 0 and 30°, or between 0 and 26°. Further, the torque considered acceptable for the joint 1 is transmitted between the outer joint portion 2 and the inner joint portion 7, and the rotating body 12 is displaced to some extent along the first longitudinal axis 3.

[0092] Unintended operations include, for example, assembling the joint 1 or assembling joint portions such as arranging the rotating body 12 on the trunnion 10.

[0093] The outer ring 13 forms exactly one or only one first stop 17 for the inner ring 15, and this first stop restricts the displacement path L 18 of the inner ring 15 relative to the outer ring 13 in a direction away from the second longitudinal axis 8 along the axis of rotation 14. This first stop 17 is formed by a protrusion on the outer ring 13, and when the inner ring 15 has advanced along the displacement path L 18, it abuts against this protrusion. Accordingly, the inner ring 15 can be displaced only up to the point where the stop surfaces come into contact with each other in this direction, that is, in a direction away from the second longitudinal axis 8 along the axis of rotation 14. During the intended operation, in the opposite direction along the axis of rotation 14, that is, in the direction towards the second longitudinal axis 8, the inner ring 15 can be displaced infinitely (restricted only by the second stop 19).

[0094] At least when the rotational axis 14 and the trunnion axis 11 are coaxially arranged, the inner ring 15 forms exactly one or only one second stop 19 with respect to the trunnion 10. The second stop 19 restricts the displacement of the inner ring 15 in the direction towards the second longitudinal axis 8 along the trunnion axis 11. In the intended operation, when the inner joint portion 7 is arranged together with the outer joint portion 2 to form the tripod joint 1, the displacement of the inner ring 15 with respect to the trunnion 10 in the direction away from the second longitudinal axis 8 along the trunnion axis 11 is not restricted, that is, it is restricted only by the first stop 17. The outer ring 13 is supported by the recess 6, whereby the first stop 17 prevents further displacement of the inner joint portion 7.

[0095] In the coasting mode (push mode and sail mode), the displacement of the inner ring 15 can be restricted by the first stop 17.

[0096] In the traction mode, the displacement of the inner ring 15 can be controlled using the second stop 19.

[0097] The first stop 17 is arranged on the second side 21 of the support 16 facing away from the second longitudinal axis 8 along the rotational axis 14. The first stop 17 is formed by a projection of the outer ring 13, which extends along the radial direction towards the rotational axis 14 and thus extends at least partially beyond the inner ring 15.

[0098] Each of the supports 16 has a circumferential surface 26 that extends over at least a length portion 25 along the rotational axis 14, and this length portion 25 is for contacting the contact surface 27 of the inner ring 15. The contact surface 27 is displaceable along the rotational axis 14 with respect to each support 16, and in the intended operation, the circumferential surface 26 contacts the contact surface 27 over most of the length portion 25 at any time.

[0099] In the design of the inner ring 15, the outer ring 13, and each support 16, all possible positions of the inner ring 15 relative to the outer ring 13 during the intended operation are considered. Thus, in a certain design variation of the tripod joint 1, it is possible to prevent the inner ring 15, which is displaceable relative to each support 16, from only partially covering each support 16 during the operation of the tripod joint 1.

[0100] Here, the displacement of the inner ring 15 along the trunnion shaft 11 away from the second longitudinal axis 8 with the trunnion shaft 11 and the rotation shaft 14 coaxially arranged is also not restricted except for the intended use. More precisely, for example, the third stop 28 shown in FIG. 13 is not provided.

[0101] In the first cross-section 33 that extends between the PCR1 23 of the inner joint portion 7 and the central body 9 and in a direction intersecting the second longitudinal axis 8, the inner joint portion 7 has a minimum first wall thickness 35 along the circumferential direction 34 around the second longitudinal axis 8 and a maximum second wall thickness 36 on the radius of the PCR1 23. The first wall thickness 35 can be made particularly large thanks to the special shape of the inner ring 15 which is substantially cylindrical. First, there is no need for the inner ring 15 to pivot or tilt for mounting on the trunnion 10. Second, in the region of the first side 20 of the support 16, there is no third stop 28, and the inner ring 15 is not equally thick so as to form a stop for this region of the inner joint portion 7 when the inner ring 15 pivots.

[0102] The angle between the rotation shaft 14 and the axis of the trunnion 11 is not required here when assembling the inner ring 15 to the trunnion 10 or removing the inner ring 15 from the trunnion, but this angle makes it possible to slightly narrow the transition area (the first wall thickness 35) between the trunnion 10 and the central body 9. The inner ring 15 can enter this transition area during the intended operation of the tripod joint 1. This first wall thickness 35 can be made thicker than that in a known joint 1, for example, the applicable range of the joint 1 regarding the transmissible torque can be increased.

[0103] The inner joint portion 7 has a spline 42 for connecting to the shaft 43 on the central body 9. The tripod joint 1 can be used in an automobile 41 (shown only here), for example, to connect each shaft 43 between the differential gear and each drive wheel, and in particular, it can be used in a side shaft that plays a role such as a drive connection (i.e., the connection between each wheel and the drive unit) of the automobile 41.

[0104] FIG. 2 is a diagram showing some angular positions of the tripod joint 1 deflected by a deflection angle 24 of 20°. Refer to the explanation of FIG. 1.

[0105] Here, along the horizontal axis, the angular positions of the cross-section of the joint 1 shown in FIGS. 3 and 4 are shown. The first curve 44 shows the position of the inner ring 13 with respect to the first longitudinal axis 3 or the center line of each recess 6. The second curve 45 shows the position of the trunnion 10 with respect to the first longitudinal axis 3.

[0106] FIG. 3 shows the tripod joint 1 (or the trunnion 10 and the rotating body 12) deflected by 20° at different positions in FIG. 2 in the traction mode. FIG. 4 shows the deflected tripod joint 1 in FIG. 3 at different positions in FIG. 2 in the push mode. FIGS. 3 and 4 a) show the tripod joint 1 at the position 0° or 360°, b) show the position at 90°, c) show the position at 180°, and d) show the position at 270°. Hereinafter, FIGS. 3 and 4 will be described together. Refer to the explanations of FIGS. 1 and 2.

[0107] In the coasting mode (push mode and sail mode), the displacement of the inner ring 15 can be restricted by the first stopper 17 (refer to FIGS. 4b) and 4d)).

[0108] In the traction mode, the displacement of the inner ring 15 can be controlled by the second stopper 19 (refer to FIGS. 3b) and 3d)).

[0109] Figure 5 shows the figure in Figure 2. Figure 6 shows the deflected tripod joint 1 by 20° at the 0° position in the traction mode. Figure 7 shows the deflected tripod joint 1 in Figure 6 at the 90° position in the traction mode. Figure 8 shows the deflected tripod joint 1 in Figure 7 at the 180° position in the traction mode. Figure 9 shows the deflected tripod joint 1 in Figure 8 at the 270° position in the traction mode. Therefore, Figures 5 to 9 show the different positions of the tripod joint 1 schematically shown only in Figures 2 to 4 using the tripod joint 1 not schematically shown. Hereinafter, Figures 5 to 9 will be described together. Refer to the description of Figures 2 to 4.

[0110] During the traction mode, the displacement of the inner ring 15 can be controlled by the second stopper 19 (see Figures 7 and 9 and compare with Figures 3b) and 3d)). The displacement of the inner ring 15 along the rotation axis 14 away from the second longitudinal axis 8 is significant. However, there is no contact between the inner ring and the first stopper 17. This contact occurs only in the push mode.

[0111] Figure 10 shows a detailed view of cross-section 33 according to Figure 1. Figure 11 shows a detailed view of the (first) cross-section 33 of the second design modification of the tripod joint 1. Hereinafter, Figures 10 and 11 will be described together. Refer to the description of Figure 1.

[0112] In Figure 10, the first stopper 17 is disposed along the rotation axis 14 on the second side 21 of the support 16 facing away from the second longitudinal axis 8. The first stopper 17 is formed by a protrusion of the outer ring 13, and this protrusion extends along the radial direction toward the rotation axis 14, thereby extending at least partially beyond the inner ring 15.

[0113] In FIG. 11, the first stop 17 is formed by a projection of the inner ring 15, and the outer ring 13 abuts against this projection when the inner ring 15 has advanced along the displacement path L18. Therefore, the inner ring 15 can only be displaced along this direction, that is, along the rotation axis 14, up to the point where the stop surfaces come into contact in the direction away from the second longitudinal axis 8. In the particularly intended operation, in the reverse direction along the rotation axis 14, that is, in the direction towards the second longitudinal axis 8, the inner ring 15 can be displaced infinitely (or restricted only by the second stop 19).

[0114] In FIG. 11, the first stop 17 is arranged along the rotation axis 14 on the first side 20 of the support 16 facing the second longitudinal axis 8. This first stop is formed by a projection of the inner ring 15, and this projection extends outward in a direction away from the rotation axis 14 along the radial direction, thereby extending at least partially beyond the outer ring 15.

[0115] FIG. 12 shows a diagram of the displacement path ROM 22 of the trunnion 10 of the tripod joint 1, showing the displacement path ROM 22 between the non-deflected position (left figure) and the maximally deflected position (right figure, here at the 90° position).

[0116] For the displacement path L18 achievable with the tripod joint 1, L>0.7×ROM is applied, and for the displacement path ROM 22, ROM = 0.5×PCR1×(1 - cos(beta max )) is applied, where · ROM is the displacement path ROM 22 of the trunnion 10 along the rotation axis 14 starting from PCR1 23 in the direction away from the second longitudinal axis 8, · PCR1 is the pitch circle radius PCR1 23 of the inner joint portion 7, · beta max is the maximum deflection angle 24 of the tripod joint 1.

[0117] ROM, or "radial outward movement of the tripod peg" (i.e., the movement of the trunnion 10 relative to the first longitudinal axis 3 in the radial outward direction), refers to the movement of the PCR1 23 (pitch circle radius) of the inner joint portion 7 between the first state and the second state. The first state is a state in which the longitudinal axes 3 and 8 are coaxially arranged with each other (see the left figure), and the second state is a state in which the longitudinal axes 3 and 8 are maximally deflected from each other (a state in which the maximum deflection angle 24 exists, see the right figure). The inner ring 15 is in contact via the second stop 19 and is displaced together with the trunnion 10. The displacement of the inner ring 15 relative to the outer ring 13 should be achievable only by the (possible) displacement path L 18, that is, when the trunnion 10 is displaced maximally (i.e., by only the ROM 22), the inner ring 15 should either form the first stop 17 by the outer ring 13 or be in contact with the first stop 17 only. In FIG. 12, the possible displacement path L 18 is shown, which is larger here than the displacement path ROM 22. In the right figure, it can be seen that there is still play between the inner ring 15 and the first stop 17. This play represents the difference between L 18 and ROM 22.

[0118] When the possible displacement path L 18 is smaller than the ROM, the displacement path ROM 22 of the trunnion 10 may be compensated by the play of the rotating body 12 in the recess. In particular, in this case, the possible displacement path L 18 should enable all of the displacement path ROM 22 to occur during the operation of the joint 1. Then, in this way, when the deflection angle 24 is very large (this occurs, for example, only during the assembly of the joint 1), the displacement path ROM 22 is compensated by the play between the rotating body 12 and the recess 6.

[0119] FIG. 13 shows a detailed view of the (first) cross-section 33 of the third design modification of the tripod joint 1. Refer to the explanations of FIGS. 1 and 10.

[0120] The inner ring 15 forms a third stop 28 against the trunnion 10, and the third stop restricts the displacement of the inner ring 15 along the trunnion axis 11 in a direction away from the second longitudinal axis 8. Only during unintended operations other than the intended operation, and only when attempting to remove the inner ring 15 from the trunnion 10, the inner ring 15 and the trunnion 10 come into contact with each other via the third stop 28.

[0121] Therefore, during the intended operation of the joint 1, the inner ring 15 and the trunnion 10 contact each other only via the second stop 19, not via the third stop 28. The third stop 28 enables the inner ring 15 to have a large displacement with respect to the trunnion 10, so that although the inner joint portion 7 is disposed within the outer joint portion 2, the inner ring 15 and the trunnion 10 cannot contact each other via the third stop 28 at all. Thus, the third stop 28 functions only as a disassembly protector for the inner ring 15 or the rotating body 12, and thereby at least the inner ring 15 can be held on the trunnion 10 by the third stop 28.

[0122] The third stop 28 is realized by a protrusion of the inner ring 15, and this protrusion extends from the inner ring 15 or from the inner circumferential surface of the inner ring 15 toward the rotation axis 14. Otherwise, the inner circumferential surface is cylindrical up to the second stop 19.

[0123] Only in the pivoting state with respect to the trunnion axis 11 (such as during an unintended operation during the assembly of the inner ring 15), the inner ring 15 can be pressed against the trunnion 10 by the third stop 28. This pivoting state has a minimum angle 29 (only shown here) of 5 to 20° between the trunnion axis 11 and the rotation axis 14.

[0124] Conversely, thereby, only when the minimum angle 29 between the trunnion axis 11 and the rotation axis 14 is less than, for example, 5° during an unintended operation (i.e., for example, during the disassembly of the inner ring 15), the inner ring 15 can be held by the trunnion 10.

[0125] During torque transmission (i.e., during the intended operation), the third stop 28 does not contact the trunnion 10, so that the third stop 28 can be designed with a correspondingly small size. In particular, due to the small size setting, only a minimum angle 29 between the trunnion axis 11 and the rotation axis 14 is required to place the inner ring 15 on the trunnion 10. Due to the small angle 29, it is possible to slightly narrow the transition area (the first wall thickness 35) between the trunnion 10 and the central body 9 into which the inner ring 15 can enter during assembly. This transition area (the first wall thickness 35) is thicker than that in the known joint 1, but for example, the applicable range of the joint 1 regarding the transmissible torque can be increased.

[0126] Regarding the design of the third stop 29 as well, the joint 1 corresponds to the definition of the proposed joint 1 described at the beginning. According to this definition, during the intended operation, the displacement of the inner ring 15 relative to the trunnion 10 in the direction away from the second longitudinal axis 8 along the trunnion axis 11 is not restricted, that is, it is restricted only by the first stop 17. When the rotating body 12 is removed from the trunnion 10, that is, only during the unintended operation of the joint 1, the third stop 28 engages.

[0127] FIG. 14 shows a detailed view of the (first) cross-section 33 of a fourth design modification of the tripod joint 1. Refer to the explanations of FIGS. 1 and 10.

[0128] The first stop 17 is formed by a stop ring 31 arranged on the outer ring 13. The stop ring 31 is designed in the form of a so-called snap ring. The stop ring is arranged in the circumferential groove of the outer ring 13 and protrudes from the groove to contact the inner ring 15 when the inner ring is displaced far enough in the direction away from the second longitudinal axis 8 along the rotation axis 14.

[0129] Since the stop ring 31 or the groove required for the stop ring requires additional structural space, the rotating body 12 may have to be larger. However, when a stop ring is provided instead of forming a protrusion on the outer ring 13, the outer ring 13 can be manufactured more economically.

[0130] FIG. 15 shows a detailed view of a (first) cross section 33 of a fifth design modification of the tripod joint 1. Refer to the description of FIG. 14.

[0131] Here, the installation space 32 for each support body 16 in the outer ring 13 is restricted by a retaining ring 31 arranged in the outer ring 13. The retaining ring is arranged in the circumferential groove of the outer ring 13 and projects from the groove so as to contact the inner ring 15 when the inner ring is displaced sufficiently far away from the second longitudinal axis 8 along the rotation axis 14.

[0132] As described above, during the intended operation, in at least some individual arrangements of the tripod joint 1, the circumferential surface 26 of each support body 16 can also contact the contact surfaces 27 of the outer ring 13 and the inner ring 15, respectively, in this case the contact surface 27 of the inner ring 15, only over a part of the length portion 25. However, only a part of the length portion 25 of the circumferential surface 26 of each support body 16 does not contact. This non - contacting part of the length portion 25 is arranged only adjacent directly to the second side 21 of each support body 16 facing away from the second longitudinal axis 8. Here, the non - contacting length portion 25 is at most 10% of the length portion 25 of the circumferential surface 26 that can contact.

[0133] This embodiment is selected, for example, in the fifth design modification when the retaining ring 31 is used to form the first stop 17, and the retaining ring also restricts the installation space 32 for each support body 16 in this case.

[0134] FIG. 16 shows a detailed view of a (first) cross section 33 of a sixth design modification of the tripod joint 1. Refer to the descriptions of FIGS. 14 and 15.

[0135] Here, the installation space 32 for each bearing body 16 in the outer ring 13 is restricted by a retaining ring 31 arranged on the outer ring 13. The retaining ring is arranged in a circumferential groove on the outer ring 13, and when the inner ring is displaced toward the second longitudinal axis 8, each bearing body 16 is retained, and the retaining ring projects from the groove only to such an extent that it does not contact the inner ring 15.

[0136] The installation space 32 can be restricted by one retaining ring 31 on each of the two sides 20, 21 of each bearing body 16, that is, on the first side 20 facing the second longitudinal axis 8 and on the second side 21 facing away from the second longitudinal axis 8 (that is, for example, by combining FIGS. 14 and 16, or FIGS. 15 and 16), although this is not shown.

[0137] The retaining ring 31 is arranged in the groove of the outer ring 13 on the first side 20 of each bearing body facing the second longitudinal axis 8. However, the retaining ring 31 can also realize a disassembly prevention device for the rotating body 12 by extending at least partially beyond the inner ring 15 toward the rotation axis 14 (in which case, the inner ring 15 cannot be pulled out from the outer ring 13). The retaining ring 31 can directly restrict the installation space 32 or can be arranged at a distance from the installation space 32.

[0138] Furthermore, on the first side 20 of each bearing body facing the second longitudinal axis 8, the retaining ring 31 arranged in the groove of the outer ring 13 can extend at least partially beyond the inner ring 15 toward the rotation axis 14, and a third stop 28 can be realized by a projection of the inner ring 15 (see FIG. 13). In this case, a disassembly protection device for the rotating body 12 is realized, on the one hand, with respect to the outer ring 13 and the inner ring 15 (the inner ring 15 cannot be pulled out from the outer ring 13 anymore), and on the other hand, with respect to the trunnion 10 (when at least the rotation axis 14 and the trunnion axis 11 are coaxially arranged, the inner ring 12 cannot be pulled out from the trunnion 10).

[0139] FIG. 17 shows a detailed view with the first feature in FIG. 1. Refer to the description of FIG. 1.

[0140] The outer ring 13 has a maximum diameter d 39 in the second cross-section 38 including the rotation axis 14, and the outer peripheral surface of the outer ring 13 is formed by a radius r 40, 0.5 < 2×r / d < 1.5 is applied.

[0141] When 2×r = d, the outer peripheral surface is spherical.

[0142] For example, when the outer ring 13 of the rotating body 12 has a spherical outer contour on its outer peripheral surface, in the circumferential direction 34 of the central body 8, the outer ring 13 can be pivoted or swiveled around the central axis of the recess 6 of the outer joint portion 2. In this case, the recess 6 of the outer joint portion 2 is correspondingly shaped, whereby the rotating body 12 is not fixed in the circumferential direction 34 of the outer joint portion 2 and is pivotable on both sides with respect to the central axis of the path of the recess 6, particularly in the range of 0 to 5° according to the resulting orbital motion. This pivoting is referred to as orbital motion or orbital angle 46. The central axis of the path is the axis of each recess 6 of the outer joint portion 2, and as a result of the axial force of the outer joint portion 2, the rotating body 12 can move along this axis.

[0143] In this case, at least partial angle compensation of the orbital motion can also be performed between the trunnion 10 and the inner ring 13. To do this, the circumferential surface of the trunnion 10 is convexly curved. The fact that this surface is convex means that the surface is designed according to a spherical segment, a barrel-shaped segment, a donut-shaped segment, or, for example, a cylindrical segment where the cylindrical axis is parallel to the second longitudinal axis 8.

[0144] FIG. 18 shows a detailed view with the second feature in FIG. 1. Refer to the description of FIG. 1.

[0145] Here, it is shown that the PCR1 23 of the inner joint portion 7 is smaller than the PCR2 37 of the outer joint portion 2, and that the PCRs 23 and 37 are the pitch circle radii.

[0146] FIG. 19 shows diagrams of the displacement RIM 30 (right diagram) and ROM 22 (left diagram) of the trunnion 10 of the tripod joint 1 between the non-deflected position and the maximally deflected position. The central diagram shows the total displacement, i.e., the sum of the RIM 30 and the ROM 22. Refer to the explanations of FIGS. 2 to 9 and FIG. 12.

[0147] The displacement path ROM 22 shows the displacement of the PCR1 23 (pitch circle radius) of the inner joint portion 7 between the first state and the second state. The first state is the state in which the longitudinal axes 3 and 8 are arranged coaxially with each other, and the second state is the state in which the longitudinal axes 3 and 8 are deflected maximally from each other (with the maximum deflection angle 24 present). These two states are shown in the central diagram of FIG. 19. The inner ring 15 is in contact via the second stop 19 and is displaced together with the trunnion 10. During the intended operation, the displacement of the inner ring 15 relative to the outer ring 13 should be realizable only by the (possible) displacement path L 18, i.e., when the trunnion 10 is displaced maximally (i.e., by only the ROM 22), the inner ring 15 should either form the first stop 17 by the outer ring 13 or the inner ring 15 should only be in contact with the first stop 17.

[0148] The (possible) displacement of the trunnion 10 relative to the inner ring 13 is restricted by the first stop 17 and, where applicable, also by the third stop 28. This (possible) displacement should correspond to at least RIM + ROM, i.e., the following applies. Displacement ≧ RIM + ROM Here, for RIM and ROM, RIM = 1.5 × PCR1 × (1 - cos(beta max )) And, ROM = 0.5 × PCR1 × (1 - cos(beta max )) applies, RIM is the displacement path RIM 30 of the trunnion 10 starting from PCR1 23 along the axis of rotation 14 in the direction towards the second longitudinal axis 8 (see the right figure), ROM is the displacement path ROM 22 of the trunnion starting from PCR1 23 along the axis of rotation 13 in the direction away from the second longitudinal axis 8 (see the left figure), PCR1 is the pitch circle radius PCR1 23 of the inner joint portion 7, beta max is the maximum deflection angle 24 of the tripod joint 1.

[0149] Therefore, the third stop 28 is arranged so that the above conditions are satisfied, that is, the (possible) displacement between the stops 17 and 28 is arranged to be greater than the sum of RIM 30 and ROM 22.

[0150] RIM or "radial inward movement of the tripod peg" (i.e., the displacement of the trunnion 10 in the radial inward direction) refers to the displacement of the PCR1 23 (pitch circle radius) of the inner joint portion 7 between the first state and the second state. The first state is the state where the longitudinal axes 3 and 8 are arranged coaxially with each other, and the second state is the state where the longitudinal axes 3 and 8 are deflected from each other to the maximum extent (the state where the maximum deflection angle 24 exists). The trunnion 10 slides along the contact surface of the inner ring 15, and this contact surface is particularly cylindrical. This displacement RIM 30 of the trunnion 10 relative to the inner ring 15 should be realizable, that is, the inner ring 15 should not yet form the third stop 28 for the trunnion 10.

[0151] Figure 20 shows the first graph. Figure 21 shows the second graph. Figure 22 shows the third graph. Figure 23 shows the fourth graph. These graphs will be described together below.

[0152] The deflection angle 24 of the tripod joint 1 is plotted on the horizontal axis. The axial force 47 acting on the tripod joint 1 is plotted on the vertical axis.

[0153] In particular, the characteristics of the tripod joint 1 are determined by the so-called ACFG value (Axial Cyclic Force Generation, the unnecessary axial force 47 generated by the joint). This value is given as the root mean square value of the force, and the unit is root mean square Newton [Nrms]. The value varies as a function of the deflection angle 24 of the joint 1, and the variation of the value as a function of the deflection angle 24 can be defined or determined for each joint. The range in which the joint 1 is used is thus limited by the maximum deflection angle 24. At this maximum deflection angle 24, the ACFG value does not exceed an amount considered acceptable. This ACFG value is plotted on the vertical axis of the graph in units of root mean square Newton [Nrms].

[0154] Each graph shows the curves of different orders of the axial force 47 in the tripod joint 1 deflected in different ways. Each curve in the upper left shows the sum of the axial forces 47 of different orders.

[0155] The first graph and the second graph show the curves of the axial force 47 of the known AARi tripod joint 1. It can be seen that the axial force 47 increases rapidly at elevated deflection angles 24 of more than 7.5° and more than 15°, respectively.

[0156] The third graph and the fourth graph show the curves of the axial force 47 of the aforementioned tripod joint 1. It can be seen that the axial force 47 remains relatively low even at elevated deflection angles 24..

[0157] The first graph and the third graph show the tripod joint 1 in the traction mode.

[0158] The second graph and the fourth graph show the tripod joint 1 in the push mode.

[0159] Therefore, it can be seen that the proposed tripod joint 1 achieves the reduction of the ACFG force and the axial force 47. At the same time, it is ensured that the rotors 12 can be mounted on the respective trunnions 10 (the inner ring 15 has no or only slight protrusions in the form of the third stop 28). Furthermore, the existing stops 17, 19, 28 are designed more advantageously than the known joints 1. In addition, the tripod joint 1 is designed to be more durable due to the relatively large first wall thickness 35.

[0160] FIG. 24 shows a detailed view of a cross section of a seventh design modification of the tripod joint 1. FIG. 25 shows a side view of the stop ring 31 forming the first stop 17 in FIG. 24. FIG. 26 shows the stop ring 31 in FIG. 25 in a top view. Hereinafter, FIGS. 24 to 26 will be described together. Refer to the description of FIGS. 14 to 16.

[0161] Here, the installation spaces 32 for the respective bearing bodies 16 in the outer ring 13 are limited by the stop rings 31 arranged on the outer ring 13. The stop rings 31 are arranged in the circumferential grooves on the outer ring 13 and protrude from the grooves so as to contact the inner ring 15 when the inner ring is displaced sufficiently far outward in a direction away from the second longitudinal axis 8 along the rotation axis 14.

[0162] The installation spaces 32 are determined by the respective stop rings 31 on both sides 20, 21 of each bearing body 16, that is, on the first side 20 facing the second longitudinal axis 8 and on the second side 21 facing away from the second longitudinal axis 8.

[0163] The retaining ring 31 for the first stop 17 has a stepped shape in the illustrated cross-section, whereby the first stop of the retaining ring 31 acting on the inner ring 15 is displaced along the rotation axis 14 (outward, i.e., away from the longitudinal axes 3, 8) out of the groove of the outer ring 13 or displaced from the fourth stop 50 acting on each support 16 by the retaining ring 31. The stepped shape may have portions extending at right angles to each other (see FIG. 24) or portions extending at an angle to each other (see FIG. 28). The retaining ring 31 is provided with a groove, whereby it is elastically deformable to be fitted into the groove of the outer ring 13.

[0164] The second stop 19 is formed by a (different) retaining ring 31 arranged in a groove on the inner ring 15. The retaining ring 31 used for the second stop 19 has a circular cross-section.

[0165] When the retaining ring 31 is used for the second stop 19, the inner ring 15 can be provided with a cylindrical inner peripheral surface, and in that case, a groove for accommodating the retaining ring 31 is provided in this inner peripheral surface.

[0166] FIG. 27 shows a detailed view of a cross-section of an eighth design modification of the tripod joint 1. Refer to the explanations in FIGS. 1 to 26, particularly FIGS. 14 to 19.

[0167] Here, the installation space 32 for each support 16 in the outer ring 13 is restricted by the retaining ring 31 arranged on the outer ring 13. The retaining ring 31 is arranged in a circumferential groove on the outer ring 13 and projects out of the groove so as to contact the inner ring 15 when the inner ring is displaced far enough along the rotation axis 14 away from the second longitudinal axis 8.

[0168] The inner ring 15 has a contour on its outer peripheral surface, whereby the inner ring 15 can be further moved along the rotation axis 14 away from the longitudinal axes 3, 8.

[0169] In this case, the inner ring 15 has a stepped shape (as a certain contour) in the first cross-section 33 running in the intersecting direction with respect to the second longitudinal axis 8, as shown in the figure. Thereby, the contact surface 48 of the inner ring 15 that interacts with each support 16 is displaced inward along the rotation axis 14 (i.e., toward the longitudinal axes 3 and 8) with respect to the end face 49 of the inner ring 15 facing outward along the rotation axis 14. The end face 49 of the inner ring 15 is the outermost surface of the inner ring 15 (outward along the rotation axis 14, i.e., away from the longitudinal axes 3 and 8).

[0170] Figure 28 shows a detailed view of a cross-section of a ninth design modification of the tripod joint 1. Refer to the explanations of FIGS. 24 and 27.

[0171] Here, the installation space 32 for each support 16 in the outer ring 13 is restricted by a retaining ring 31 arranged on the outer ring 13. The retaining ring 31 is arranged in a circumferential groove on the outer ring 13 and protrudes from the groove to contact the inner ring 15 when the inner ring is displaced sufficiently far away from the second longitudinal axis 8 along the rotation axis 14.

[0172] The retaining ring 31 has a stepped shape in cross-section. Thereby, the first stop 17 of the retaining ring 31 acting on the inner ring 15 is displaced along the rotation axis 14 (outward, i.e., away from the longitudinal axes 3 and 8) from the groove of the outer ring 24 or is displaced from the fourth stop 50 acting on each support 16 by the retaining ring 31.

[0173] The stepped shape has an inclined portion. The inclined portion of the retaining ring 31 interacts with a (substantially) parallel surface of the inner ring 15 and forms the first stop 17.

[0174] Figure 29 shows a detailed view of a cross-section of a tenth design modification of the tripod joint 1. Refer to the explanations of FIGS. 24 and 28.

[0175] Here, the installation space 32 for each support 16 in the outer ring 13 is restricted by a retaining ring 31 arranged on the outer ring 13. The retaining ring 31 is arranged in a circumferential groove on the outer ring 13 and protrudes from the groove so as to contact the inner ring when the inner ring is displaced far enough away from the second longitudinal axis 8 along the rotation axis 14.

[0176] In contrast to the eighth design variant according to FIG. 28, the inner ring 15 has a cylindrical outer peripheral surface (i.e., the contour does not deviate from its shape).

Explanation of reference numerals

[0177] 1 Tripod joint 2 Outer joint part 3 First longitudinal axis 4 Cavity 5 End 6 Recess 7 Inner joint part 8 Second longitudinal axis 9 Central body 10 Trunnion 11 Trunnion axis 12 Rotating body 13 Outer ring 14 Rotation axis 15 Inner ring 16 Support 17 First stop 18 Displacement path L 19 Second stop 20 First side 21 Second side 22 Displacement path ROM 23 Pitch circle radius PCR1 24 Deflection angle beta max 25 Length 26 Peripheral surface 27 Contact surface 28 Third stop 29 Minimum angle 30 Displacement path RIM 31 Retaining ring 32 Installation space 33 First cross-section 34 - week direction 35 First wall thickness 36 Second wall thickness 37 Pitch circle radius PCR2 38 Second cross - section 39 Maximum diameter d 40 Radius r 41 Automobile 42 Spline 43 Shaft 44 First curve 45 Second curve 46 Orbit angle 47 Axial force (ACFG) 48 Contact surface 49 End face 50 Fourth stopper

Claims

1. A tripod joint (1), comprising: an outer joint portion (2) and an inner joint portion (7); wherein the outer joint portion (2) has a first longitudinal axis (3) and a cavity (4) extending parallel to the first longitudinal axis (3) and having an open end (5); three recesses (6) extending parallel to the first longitudinal axis (3) are formed in the outer joint portion (2); the inner joint portion (7) has a second longitudinal axis (8); the inner joint portion (7) has at least one central body (9), and three trunnions (10) having trunnion axes (11) extending radially from the second longitudinal axis (8) are formed on the central body (9); a rotating body (12) is disposed on each of the trunnions (10); the rotating body (12) has at least one outer ring (13) and an inner ring (15) rotatable around a common rotation axis (14), and a bearing body (16) disposed between the outer ring (13) and the inner ring (15); each of the rotating bodies (12) is movably received in the recess (6) and can move along the first longitudinal axis (3); in the intended operation of the tripod joint (1), one of the inner ring (15) and the outer ring (13) is displaceable along the rotation axis (14) relative to the other of the inner ring (15) and the outer ring (13) together with the bearing body (16); the outer ring (13) forms a first stop (17) for the inner ring (15); the first stop (17) limits the displacement path L (18) of the inner ring (15) relative to the outer ring (13) along the rotation axis (14) in a direction away from the second longitudinal axis (8); at least when the rotation axis (14) and the trunnion axis (11) are coaxially arranged, the inner ring (15) forms a second stop (19) for the trunnion (10); the second stop limits the displacement of the inner ring (15) along the trunnion axis (11) in a direction towards the second longitudinal axis (8); in the intended operation, the displacement of the inner ring (15) relative to the trunnion (10) along the trunnion axis (11) in a direction away from the second longitudinal axis (8) is not limited, that is, it is limited only by the first stop (17). Tripod joint.

2. The tripod joint (1) according to claim 1, wherein the first stop (17) is arranged along the rotation axis (14) on a first side (20) of the support body (16) facing the second longitudinal axis (8), or on a second side (21) of the support body (16) facing away from the second longitudinal axis (8), Tripod joint.

3. The tripod joint (1) according to claim 1 or 2, wherein in the displacement path L (18), L > 0.7 × ROM is applicable, and in the ROM (22), ROM = 0.5 × PCR1 × (1 - cos(beta ｍａｘ )) is applicable, wherein the ROM is the displacement path ROM (22) of the trunnion (10) along the rotation axis (14) starting from the PCR1 (23) and in a direction away from the second longitudinal axis (8), wherein the PCR1 (23) is the pitch circle radius PCR1 (23) of the inner joint part (7), The beta ｍａｘ is the maximum deflection angle (24) of the tripod joint (1). Tripod joint.

4. The tripod joint (1) according to claim 1 or 2, wherein the inner ring (15) forms a third stop (28) for the trunnion (10), the third stop restricts the displacement of the inner ring (15) along the trunnion axis (11) in a direction away from the second longitudinal axis (8), and the inner ring (15) and the trunnion (10) come into contact with each other via the third stop (28) only during an operation other than the intended operation and only when attempting to remove the inner ring (15) from the trunnion (10), Tripod joint.

5. The tripod joint (1) according to claim 4, wherein the inner ring (15) can be pressed against the trunnion (10) by the third stop (28) only in a pivoting state with respect to the trunnion axis (11), the pivoting state having a minimum angle (29) of 5 to 20° between the trunnion axis (11) and the rotation axis (14), Tripod joint.

6. The tripod joint (1) according to claim 5, wherein the displacement of the trunnion (11) with respect to the inner ring (15) is restricted by the first stop (17) and the third stop (28), the displacement being at least equal to RIM + ROM, and for RIM (30) and ROM (22), is applicable, RIM = 1.5 × PCR1 × (1 - cos(beta ｍａｘ ), and ROM = 0.5 × PCR1 × (1 - cos(beta ｍａｘ ) Tripod joint. The RIM is a displacement movement RIM (30) of the trunnion (10) in a direction toward the second longitudinal axis (8) along the rotation axis (14) starting from the PCR1 (23). The ROM is a displacement path ROM (22) of the trunnion (10) in a direction away from the second longitudinal axis (8) along the rotation axis (14) starting from the PCR1 (23). The PCR1 (23) is the pitch circle radius PCR1 (23) of the inner joint portion (7). said beta ｍａｘ is the maximum deflection angle (24) of said tripod type joint (1), Tripod type joint.

7. The tripod type joint (1) according to claim 1 or 2, when the trunnion axis (11) and the rotation axis (14) are coaxially arranged, even outside the intended use, the displacement of the inner ring (15) in a direction away from the second longitudinal axis (8) along the trunnion axis (11) is not restricted. Tripod type joint.

8. The tripod type joint (1) according to claim 1 or 2, the first stopper (17) is formed from the outer ring (13) itself or formed by a retaining ring (31) arranged on the outer ring (13). Tripod type joint.

9. The tripod type joint (1) according to claim 1 or 2, the inner ring (15) has a stepped shape in a first cross section (33) extending in a direction intersecting the second longitudinal axis (8), whereby the contact surface (48) of the inner ring (15) cooperating with each support (16) is displaced inward along the rotation axis (14) with respect to the end face (49) of the inner ring (15). Tripod type joint.

10. The tripod type joint (1) according to claim 1 or 2, the installation space (32) for each support (16) in the outer ring (13) is restricted by a retaining ring (31) arranged on the outer ring (13). Tripod type joint.

11. The tripod type joint (1) according to claim 10, the retaining ring (31) has a stepped shape in a first cross section (33) extending in a direction intersecting the second longitudinal axis (8). As a result, the first stop (17) of the stop ring (31) acting on the inner ring (15) is displaced outward along the rotation axis (14) from a fourth stop (50) formed toward the support (16) by the stop ring (31). Tripod joint. **Claim 12** A tripod joint (1) according to claim 1 or 2, In a first cross section (33) extending between the PCR1 (23) of the inner joint part (7) and the central body (9) and in a direction intersecting the second longitudinal axis (8), The inner joint part (7) has a minimum first wall thickness (35) along a circumferential direction (34) around the second longitudinal axis (8), and a maximum second wall thickness (36) on the radius of the PCR1 (23), the ratio of the first wall thickness to the second wall thickness being at least 0.7, wherein the PCR1 (23) is the pitch circle radius of the inner joint part (7). Tripod joint. **Claim 13** A tripod joint (1) according to claim 1 or 2, wherein the PCR1 (23) of the inner joint part (7) is smaller than the PCR2 (37) of the outer joint part (2), wherein the PCR (23, 37) is the pitch circle radius. Tripod joint. **Claim 14** A tripod joint (1) according to claim 1 or 2, wherein the outer ring (13) has a maximum diameter d (39) in a second cross section (38) including the rotation axis (14), the outer peripheral surface (40) of the outer ring (13) being formed by a radius r (41), where 0.5 < 2×r / d < 1.

5. Tripod joint. **Claim 15** An automobile (42) comprising at least one tripod joint (1) according to claim 1 or 2.

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