DE102022133034A1 - Outer joint part, inner joint part and roller for a tripod-type sliding joint, tripod-type sliding joint and method for producing an inner joint part - Google Patents

Abstract

The invention is based on an outer joint part, the radial outer contact geometry of which is formed by a flat surface (10.11) slightly inclined relative to an orthogonal line to the axis of rotation of the respective roller (30) and a convexly curved transition surface (10.12) extending in the direction of the axis of rotation of the respective roller (30). The opposite side of the inclined flat surface (10.11) merges into the roller guide surface (10.3) via a concavely curved surface (10.10).The spherical segment-shaped pin head (20.4) of the pin (20.3) of the inner joint part is elliptically flattened on two diametrically opposite and 90° to the spherical torque-transmitting circumferential areas (20.6), the major semi-axis (20.8) of which runs orthogonal to the axis of rotation (3) of the tripod star (20).The transition from the spherical main force transmission surface (30.5) to the outer and inner end face (30.6) of the rollers (30) is formed by a flat surface (30.7). At each transition from the spherical main force transmission surface (30.5) to the flat surface (30.7), at least one transition radius (R33a, R33b) is provided, as well as at least one transition radius (R34a, R34b) from the flat surface (30.7) to the outer and inner end faces (30.6).

Description

State of the art

The invention is based on an outer joint part, an inner joint part and a roller for a sliding joint of the type of a tripod constant velocity joint according to the preamble of claims 1, 11 or 16, a sliding joint of the type of a tripod constant velocity joint according to the preamble of claim 21 and a method for producing an inner joint part according to the preamble of claim 15.

Sliding joints of the tripod constant velocity joint type are used in particular in vehicle drive trains to transmit torque between two shafts which, in operation, perform both an axial displacement and a bending relative to each other. The main components of such sliding joints are an outer joint part in the form of a bell, in which an inner joint part in the form of a tripod star is arranged so that it can be axially displaced and bent via rollers. Such sliding joints have been known for a long time and are used, for example, in the EN 10 2013 106 868 B3 described in detail. Due to the interaction of all three components, it is obvious that each individual component, as well as their interaction, has an influence on the functional properties of the sliding joint, with key properties of such joints being their efficiency, their noise level, their vibration behavior and their psychoacoustic roughness, a measure of the "humming" of a noise. The last three properties are summarized in the so-called NVH behavior (noise, vibration, harshness). A fifth property, which can also be influenced by the design conditions of the acting components, is the effectiveness of the lubrication of the sliding joint. As with all components that interact with one another under load in the operating state, a crucial design factor is the play between the acting components, which in turn influences the NVH behavior in particular. This affects both the contact points between the roller tracks of the bell, also known as guide grooves, and the outer ring of the rollers, as well as the contact points between the outer tracks of the tripod pins and the inner ring of the rollers. The friction occurring at these contact points leads to periodically changing friction coefficients, which together with the kinematically imposed wobble motion of the tripod star and the roller motion result in an axial force excitation that mainly corresponds to the third order.

As a representative of the extremely extensive state of the art in tripod constant velocity joints, the outer joint part is WO 2019/059204 A1 , in which a special form of the installation geometry for the rollers is shown. Both an installation geometry can be seen that is formed by radii and also passes over a radius into the free space between the bell and the outer face of the rollers, as well as an installation geometry that is formed by flat areas and passes over without radii into the free space between the bell and the outer face of the rollers.

For the inner joint part, the patent already mentioned in the introduction EN 10 2013 106 868 B3 as well as the WO90/07067 A1 Both publications show a cone head that deviates from the spherical shape. While the EN 10 2013 106 868 B3 described pin head deviates from the spherical shape in the area of contact with the inner ring of the roller, i.e. in the torque-transmitting plane, the pin head in the publication WO 2019/059204 A1 flattened at the surface areas offset by 90° from the torque-transmitting plane and thus unloaded.

For the scooter, the three publications DE 44 39 965 A1 , DE 43 05 278 C1 and DE 43 27 606 C2 In the rollers described here, both the outer ring and the inner ring have a contact function, whereby the outer ring has a spherical surface adapted to the roller guide surface of the bell, which completely rests on the roller guide surface of the bell, while the inner ring rests on the bell with its outer face. In the DE 43 05 278 C1 A bevel is provided on the transition area facing the axis of rotation of the tripod joint from the spherical main transmission surface to the inner end face, by means of which a larger bending angle of the joint is achieved.

The disadvantage of these sliding joints is an increased third-order axial force generation and, as a result, NVH abnormalities, especially at high torques and bending.

A method for producing a tripod constant velocity joint, in which the tripod star is formed in a split mold, is described in the EN 10 2020 212 991 A1 described. The tool parting plane runs through a plane that is spanned by the longitudinal axis of the respective pin and the rotation axis of the tripod star. The non-circular cross-section, which is characterized by a flattening in the direction of rotation of the tripod star, is already finished, i.e. calibrated, during the forming step, whereby a final calibrating post-processing by means of complex material-removing hard machining, for example by grinding, is not excluded.

The invention is based on the object of optimizing the known sliding joints of the tripod constant velocity joint type or its components in such a way that they generate the lowest possible self-induced axial force and have minimal NVH emissions with improved efficiency. Furthermore, the object of the invention is to improve the known methods for producing a tripod joint in such a way that complex material-removing hard machining, for example grinding or fine grinding, is avoided.

The object is achieved according to the invention by the characterizing features of claims 1, 11, 15, 16 and/or 21.

The invention and its advantages

The main contribution of the outer joint part of the sliding joint, hereinafter referred to as the bell, to improving the efficiency and minimizing the NVH emissions of the sliding joint consists in a modified radial outer contact geometry for the rollers of the sliding joint in the guide grooves of the bell. The contact geometry here is the area in the guide grooves of the bell where the rollers rest with the transition area from their spherical main force transmission surface, i.e. their radial peripheral surface, to their outward-facing front surface. The area of the guide grooves where the rollers rest at least partially with their radial peripheral surface is referred to as the roller guide surface.

As part of an extensive optimization program carried out on the sliding joint, it was discovered that the radial outer contact geometry of the bell is formed according to the invention by a flat surface that is slightly inclined at an angle γ relative to an orthogonal to the axis of rotation of the respective roller, and a convexly curved surface that adjoins the axis of rotation of the respective roller and merges into a recess between the front surface of the respective roller. The opposite side of the inclined flat surface merges into the roller guide surface via a concavely curved surface.

In an advantageous embodiment of the invention, the angle γ is approximately 1° to 3°. This results in the formation of a narrowing gap in the direction of the starting point of the roller, i.e. a point contact, which improves lubrication and consequently the NVH behavior. In addition, the radius of the concave curved surface that leads into the roller guide surface can be selected to be greater than 2.5 mm, which increases the service life of the forging tool used to produce the bell.

In another embodiment of the invention, the horizontal distance between the outer starting points of the rollers on the system geometry according to the invention and the axis of symmetry of the bell bisecting the track per track is 0.29 times the diameter of the outer ring of the roller. Depending on the roller class, this value can deviate by +/- 1.5%.

In a particularly advantageous embodiment of the invention, a narrow flat surface is arranged between the concavely curved surface and the roller guide surface. This ensures tangent continuity in the transition area of these surfaces, which reduces notch stresses in the transitions to the concavely curved surface and the roller guide surface and thus maximizes the transmission capacity of the component.

A further design of the transition area with the same aim as mentioned above can consist in providing a narrow convex curved surface instead of the narrow flat surface between the concave curved surface and the roller guide surface, so that a kind of turning point is created in the surface profile between the system geometry and the roller guide surface.

According to a likewise advantageous embodiment of the invention, the convexly curved surface extending in the direction of the axis of rotation of the respective roller is divided into two curved partial surfaces, and the transition into the recess (or: the free space) is formed by an additional partial surface with a concave curvature, so that the convexly curved partial surface merges into the free space without a step.

According to a further advantageous embodiment of the invention, the convex curved surface, which merges in the radial direction into the clamping diameter surface, is divided into three partial surfaces, with a concave curved partial surface being arranged between the two convex curved partial surfaces. In this variant of the bell, its clamping diameter is reduced so that the roller can also bend radially towards the inside, ie under load. inward-facing transition of the roller guide surface into the clamping diameter surface, creating a second starting point for the roller. This creates a secondary starting geometry for each half of the track, with the first two partial surfaces, i.e. the first convex and the concave partial surface following it, serving as auxiliary surfaces to ensure freedom of movement. The additional starting surface(s) change the tilting kinematics of the roller when the rolling direction changes, thereby avoiding unfavorable friction conditions, which in turn has a positive effect on the periodic NHV excitation of the tripod.

wobei der Glocken-PCD (PCD = pitch circle diameter) der Teilkreisdurchmesser der Glocke in der Mitte ihrer Rollenführungsfläche ist. Dies begründet sich durch den Mindestradius beim Schmiedewerkzeug der Glocke.According to an advantageous embodiment of the invention in this regard, the radii of the three curved partial surfaces are calculated according to the formula $$\text{R}19=\text{R}20=\text{R}21=\left(2*\text{Bell PCD}\right)/\mathrm{51,}$$

where the bell PCD (pitch circle diameter) is the pitch circle diameter of the bell at the center of its roller guide surface. This is due to the minimum radius of the bell forging tool.

wobei s3 der horizontale Abstand der äußeren Anlaufpunkte (AP1) zur laufbahnhalbierenden Symmetrieachse ist. Dieses rein rechnerische Spiel ist ein theoretisches Spiel, das sich im unbelasteten Zustand des Verschiebegelenks einstellt.According to an additional advantageous embodiment of the invention, the raceway clearance δ ₁ between the roller guide surface of the bell and the outer ring of the roller as well as the frontal or axial raceway clearance δ ₂ between the contact surface of the bell in the area of its radial outer contact geometry, i.e. also close to the inclined surface at the starting point 1, and the outer front surface of the roller in the unloaded state are calculated according to the formula $${\mathrm{\delta }}_1={\mathrm{\delta }}_2=\text{tan}\left(0.46°\right)*\text{s}\mathrm{3,}$$

where s3 is the horizontal distance between the outer starting points (AP1) and the axis of symmetry bisecting the raceway. This purely calculated play is a theoretical play that occurs when the sliding joint is not under load.

In this variant of the bell, the raceway clearance between its contact surface in the area of the first and second partial surfaces adjoining the roller guide surfaces radially inwards, i.e. in the area of the second contact point, and the outer ring of the roller in the unloaded state is a maximum of 0.8 times the radial raceway clearance.

The main contribution of the inner joint part of the plunging joint, hereinafter referred to as the tripod star, to improving the efficiency and minimizing the NVH emissions of the plunging joint consists in a modification of its spherical pin head. As is known, the torque of the joint is transmitted via the spherical peripheral areas of the pin heads, hereinafter referred to as torque-transmitting surfaces. It is already known from the prior art to flatten the pin heads of the tripod star, with these flattenings lying in the area of the surface areas that are not loaded in the operating state, i.e. those surface areas that are intersected by a plane lying in the axis of rotation of the tripod star. The torque-transmitting surfaces are therefore perpendicular to this plane, i.e. a plane that intersects the axis of rotation of the tripod star. According to the invention, the flattening of the spherical segment is designed as an elliptical flattening, the major semi-axis of which runs orthogonal to the axis of rotation of the tripod star. This flattening creates two grease pockets between the pin head and the inner ring of the roller. The small semi-axis, which is always smaller than the radius of the ball segment and can be measured on the component, determines the inward indentation and thus also the depth of the grease pocket, which has a positive effect on the NHV behavior of the sliding joint. The large semi-axis mainly determines the width of the flattening. The largest cross-section of the pin head determines the PCD of the tripod star.

In an advantageous embodiment of the invention, the pitch circle diameter (PCD) of the spherical segment-shaped heads of the pins deviates by up to +/- 1.6% from the PCD of the bell. In particular, when using low-performance greases as lubricants, there are advantages in the area of self-induced axial forces if the PCD of the tripod star is smaller than the PCD of the bell.

According to an advantageous embodiment of the invention in this regard, the small ellipse semi-axis b24 = (0.990 to 0.992) times the radius of the sphere in the non-flattened area of the pin head and the large ellipse semi-axis a24 = (1.20 to 1.21) times the radius of the sphere in the non-flattened area of the pin head.

The above-mentioned elliptical flattening on the pin heads of the tripod star also has manufacturing advantages. It is already produced during the manufacture of the blank of the tripod star by extruding it perpendicular to the clamping plane and parallel to the radius of the ball. The front surfaces of the star hub and its gearing are then finished by material-removing machining. The tripod star is then hardened. Finally, the torque-transmitting surfaces of the ball segment are made rotationally symmetrical by material-removing hard machining. machined to the respective journal. Due to the elliptical-spherical shape of the recess, no sharp edges are formed during the final hard machining process of the torque-transmitting surfaces, so that an improved stress curve is achieved in this area at larger bending angles and, as a result, high torques can be transmitted. In addition, diggings into the roller inner ring are minimized. Due to the minimization of friction, particularly at high bending angles, where the power transmission ellipse moves closer to the recess, there is also significantly better NVH behavior compared to designs with a wider recess in the journal head.

As a third component of the sliding joint, a modification of the spherical main force transmission surface of the rollers arranged angularly movable on the pin heads of the tripod star contributes to improving the efficiency and minimizing the NVH emissions of the sliding joint. According to the invention, the transition from the spherical main force transmission surface to the outer and inner end faces of the rollers is formed by a short flat surface. In addition, a transition radius is provided at the respective transition from the spherical main force transmission surface to the short flat surface and from the flat surface to the outer and inner end faces. When bent, the transition areas between the short flat surface and the outer end face come into contact with the starting geometry of the bell. By modifying these transition areas according to the invention, a lower friction behavior is achieved in the case of load under bending, which has a positive effect on the axial force excitation.

In an advantageous embodiment of the invention, the transition radii from the spherical main force transmission surface to the short flat surface are greater than 1.5 mm and/or the transition radii from the flat surface to the outer and inner end faces are smaller than 0.1 mm.

In a particularly advantageous embodiment of the invention, the short flat surface is divided into two partial surfaces, with the second partial surface, viewed in the axial direction, merging over a radius into the respective front surface of the scooter. Through extensive investigations into the NHV behavior of tripod-type sliding joints, this transition into the respective front surface was identified as the main cause of undesirable NHV excitations. And so, in particular, by rounding these transitions, an additional reduction in friction excitation was achieved.

The inclination of the two short, flat partial surfaces also has an additional influence on the reduction of friction excitation. During the tests, it was found that the first partial surface immediately adjacent to the spherical main force transmission surface is inclined by 35° and the second partial surface adjacent to the latter is inclined by 20° relative to the respective front surface.

Due to the complexity of the influences of all of the above-mentioned features of the main components of a plunging joint of the tripod constant velocity joint type and the various operating conditions, it goes without saying that any conceivable combination of at least one feature according to the invention of a first main component with at least one feature according to the invention of a second main component and/or with at least one feature according to the invention of a third main component of the tripod constant velocity joint can contribute to improving the NHV behavior of the plunging joint.

• - dass die Glocke die Merkmale des Anspruchs 1 aufweist, wobei der Winkel γ 2° beträgt, der horizontale Abstand der äußeren Anlaufpunkte der Roller an der erfindungsgemäßen Anlagegeometrie zur laufbahnhalbierenden Symmetrieachse der Glocke pro Laufbahn das 0,29-fache des Durchmessers des Außenrings des Rollers beträgt, zwischen der konkav gekrümmten Fläche und der Rollenführungsfläche eine schmale ebene Fläche angeordnet ist, die sich in Richtung der Drehachse des jeweiligen Rollers erstreckende konvex gekrümmte Fläche in zwei gekrümmte Teilflächen aufgeteilt, und der Übergang in die Ausnehmung (oder: den Freiraum) durch eine zusätzliche Teilfläche mit einer konkaven Krümmung gebildet wird, so dass die konvex gekrümmte Teilfläche ohne einen Absatz in den Freiraum übergeht,
• - dass die Abflachung des Kugelsegments des kugelsegmentförmigen Zapfenkopfes des Tripodesterns als eine elliptische Abflachung ausgebildet ist, deren große Halbachse orthogonal zur Drehachse des Tripodesterns verläuft, wobei der PCD der kugelsegmentförmigen Köpfe der Zapfen 0,4 % kleiner ist als der PCD der Glocke, die große Halbachse der elliptischen Abflachung a24 = 1 ,2*R24 und die kleine Halbachse der elliptischen Abflachung b24 = 0,991 *R24 beträgt, und
• - dass der Übergang von der sphärischen Hauptkraftübertragungsfläche zu der äußeren und inneren Stirnfläche des Rolles durch eine ebene Fläche gebildet ist und an dem jeweiligen Übergang von der sphärischen Hauptkraftübertragungsfläche zu der ebenen Fläche jeweils ein erster Übergangsradius sowie von der jeweiligen ebenen Fläche in die äußere bzw. inneren Stirnfläche jeweils ein zweiter Übergangsradius vorgesehen ist, wobei durch Aufteilung der ebenen Fläche in zwei Teilflächen eine Doppelschräge entsteht, der Winkel der jeweils an die Stirnfläche angrenzenden ebenen Teilfläche zur Stirnfläche 20° und der zweite Übergangsradius von der letztgenannten Teilfläche in die jeweilige Stirnfläche R = 1 mm beträgt.

A preferred combination of all three main ingredients is

• - that the bell has the features of claim 1, wherein the angle γ is 2°, the horizontal distance of the outer starting points of the rollers on the system geometry according to the invention to the axis of symmetry of the bell bisecting the track per track is 0.29 times the diameter of the outer ring of the roller, a narrow flat surface is arranged between the concavely curved surface and the roller guide surface, the convexly curved surface extending in the direction of the axis of rotation of the respective roller is divided into two curved partial surfaces, and the transition into the recess (or: the free space) is formed by an additional partial surface with a concave curvature, so that the convexly curved partial surface merges into the free space without a step,
• - that the flattening of the spherical segment of the spherical segment-shaped pin head of the tripod star is designed as an elliptical flattening, the major semi-axis of which is orthogonal to the axis of rotation of the tripod star, the PCD of the spherical segment-shaped heads of the pins being 0.4% smaller than the PCD of the bell, the major semi-axis of the elliptical flattening being a24 = 1.2*R24 and the minor semi-axis of the elliptical flattening being b24 = 0.991*R24, and
• - that the transition from the spherical main force transmission surface to the outer and inner end face of the roller is formed by a flat surface and at the respective A first transition radius is provided for the transition from the spherical main force transmission surface to the flat surface and a second transition radius is provided from the respective flat surface to the outer or inner end face, whereby a double bevel is created by dividing the flat surface into two partial surfaces, the angle of the flat partial surface adjacent to the end face to the end face is 20° and the second transition radius from the latter partial surface to the respective end face is R = 1 mm.

The tripod-type sliding joint according to the invention is suitable for all sliding joint applications on vehicles. It falls into the category of tripods with angle compensation of the rollers, i.e. the rollers and tripod star axis do not necessarily have to be at an angle of 90° to each other. Instead, the rollers are ideally only guided in their track and do not build up a helix angle to it.

Further advantages and advantageous embodiments of the invention can be found in the following description, the claims and the drawings.

drawing

• 1 eine räumliche Explosiv-Darstellung der Hauptbestandteile eines Verschiebegelenks vom Typ eines Tripode-Gleichlaufgelenks,
• 2 eine Vorderansicht des Verschiebegelenks aus 1 im montierten Zustand mit gegenüber dem Gelenkaußenteil gebeugtem Gelenkinnenteil,
• 3 einen Schnitt durch ein montiertes Gelenk senkrecht zur Drehachse des Gelenkinnenteils in einer ersten Variante,
• 4 einen Schnitt durch ein montiertes Gelenk senkrecht zur Drehachse des Gelenkinnenteils in einer zweiten Variante,
• 5 einen Schnitt durch das Gelenkaußenteil senkrecht zu dessen Drehachse einer ersten Variante des Übergangs von der Rollenführungsfläche zu einem ersten Anlaufpunkt,
• 6 einen Schnitt durch das Gelenkaußenteil senkrecht zu dessen Drehachse einer zweiten Variante des Übergangs von der Rollenführungsfläche zu dem ersten Anlaufpunkt,
• 7 einen Ausschnitt J1 aus 5,
• 8 das Detail J2 aus 7,
• 9 einen Ausschnitt J3 aus 6,
• 10 das Detail J4 aus 9,
• 11 einen Ausschnitt J5 der ersten Variante aus 5 mit einem Roller,
• 12 einen Ausschnitt J6 einer Kombination der beiden Varianten aus 7 und 9 mit einem Roller,
• 13 eine isometrische Darstellung eines Gelenkinnenteils,
• 14 eine Vorderansicht des Gelenkinnenteils aus 13,
• 15 einen Schnitt A-A durch das Gelenkinnenteil aus 14,
• 16 einen Ausschnitt K1 aus 15,
• 17 einen Schnitt B-B durch das Gelenkinnenteil aus 14,
• 18 einen Schnitt C-C durch das Gelenkinnenteil aus 14,
• 19 einen Ausschnitt K2 aus 18,
• 20 eine Axialschnittdarstellung einer ersten Variante eines Rollers,
• 21 einen Ausschnitt L1 mit vergrößerter Darstellung der Anlagegeometrie des Rollers aus 20,
• 22 eine Axialschnittdarstellung einer zweiten Variante eines Rollers,
• 23 einen Ausschnitt L2 mit vergrößerter Darstellung der Anlagegeometrie der zweiten Variante des Rollers aus 22,

Preferred embodiments of the subject matter according to the invention are shown in the drawings and are explained in more detail below. They show

• 1 a spatial exploded view of the main components of a tripod constant velocity joint,
• 2 a front view of the sliding joint 1 in the assembled state with the inner joint part bent relative to the outer joint part,
• 3 a section through an assembled joint perpendicular to the axis of rotation of the inner joint part in a first variant,
• 4 a section through an assembled joint perpendicular to the axis of rotation of the inner joint part in a second variant,
• 5 a section through the outer joint part perpendicular to its axis of rotation of a first variant of the transition from the roller guide surface to a first starting point,
• 6 a section through the outer joint part perpendicular to its axis of rotation of a second variant of the transition from the roller guide surface to the first contact point,
• 7 a section J1 from 5 ,
• 8th the detail J2 from 7 ,
• 9 a section J3 from 6 ,
• 10 the detail J4 from 9 ,
• 11 a section J5 of the first variant from 5 with a scooter,
• 12 a section J6 of a combination of the two variants 7 and 9 with a scooter,
• 13 an isometric representation of an inner joint part,
• 14 a front view of the inner joint part 13 ,
• 15 a section AA through the inner joint part 14 ,
• 16 an excerpt K1 from 15 ,
• 17 a section BB through the inner joint part 14 ,
• 18 a section CC through the inner joint part 14 ,
• 19 a section K2 from 18 ,
• 20 an axial section view of a first variant of a scooter,
• 21 a section L1 with an enlarged view of the scooter’s geometry 20 ,
• 22 an axial section view of a second variant of a scooter,
• 23 a section L2 with an enlarged view of the system geometry of the second variant of the scooter from 22 ,

Description of the embodiments

• - einem Gelenkaußenteil in Form einer um eine erste Drehachse 2 rotierenden und mit einer hier nicht dargestellten ersten Welle drehfest verbindbaren zylindrischen Glocke 10,
• - einem Gelenkinnenteil in Form eines um eine zweite Drehachse 3 rotierenden und mit einer Welle 4 drehfest verbindbaren Tripodesterns 20
• - und Rollern 30,

wobei das Gelenkinnenteil, also der Tripodestern 20, in dem Gelenkaußenteil, also der Glocke 10, über die Roller 30 axial verschiebbar und mit seiner zweiten Drehachse 3 gegenüber der ersten Drehachse 2 der Glocke 10 winkelbeweglich angeordnet ist. Die nicht dargestellte erste Welle kann über einen Ansatz 10.1 mit der Glocke 10 drehfest, beispielsweise durch Schweißen, verbunden werden. 1 shows a spatial exploded view and 2 a front view of a plunging joint of the tripod constant velocity joint type 1 with its main components, namely

• - an outer joint part in the form of a cylindrical bell 10 rotating about a first axis of rotation 2 and rotatably connected to a first shaft (not shown here),
• - an inner joint part in the form of a tripod star 20 rotating about a second axis of rotation 3 and rotatably connected to a shaft 4
• - and scooters 30,

wherein the inner joint part, i.e. the tripod star 20, is axially displaceable in the outer joint part, i.e. the bell 10, via the rollers 30 and is arranged with its second axis of rotation 3 relative to the first axis of rotation 2 of the bell 10 so as to be angularly movable. The first shaft shown can be connected to the bell 10 in a rotationally fixed manner via an attachment 10.1, for example by welding.

The 3 and 4 show a section through an assembled sliding joint perpendicular to the axis of rotation of the inner joint part without bending, i.e. with the first and second axes of rotation 2, 3 aligned, and the 5 and 6 each a section through the bell 10 as a single part, whereby the 3 and 5 a first variant with respect to the roller guide in the bell 10 in the radial direction outwards and the 4 and 6 each represent a second variant of this area.

As can be seen from the 5 and 6 As can be seen, the bell 10 has an outer radius R10 and an inner radius R11 for the first variant or R12 for a second variant to be described later with respect to the roller guide in the bell 10 in the radial direction inwards, wherein the inner radii R11, R12 are also referred to as clamping radii of the bell 10 and the inner circumference as the clamping diameter area 10.2 and the inner radius R11 of the first variant ( 6 ) is larger than the inner radius R12 of the second variant ( 5 ). The bending angle β (not shown) that can be achieved between the first shaft of the bell 10 and the second shaft 4 of the tripod star 20 is determined by the inner or clamping radius R11, R12 when the tripod star 20 is retracted into the bell 10. The entirety of the contours that deviate from the inner radius R11, R12 is referred to as the raceway of the bell 10, whereby the bell 10 has three raceway areas. The raceway area that is immediately adjacent to the clamping diameter surface 10.2 in the circumferential direction is referred to as the roller guide surface 10.3 and is formed from two abutting partial surfaces with the same radius R13 ( 7 and 9 ), which each have their origin in a first radius center 10.4 and a second radius center 10.5, whereby the two radius centers 10.4 and 10.5 are offset by a radial offset from the axis of symmetry, i.e. have a radial offset s1 from one another. This roller guide surface 10.3 is also referred to as a Gothic roller guide surface. In the area where they meet, the two partial surfaces are connected to one another via a base track rounding radius R14. The double outer radius R10, i.e. the large outer diameter of the bell 10, describes the maximum radial bell dimension. Opposite the radially outward-facing end face of the roller 30, the contour of the bell 10 is set back so that a free space 10.6 is formed between the bell 10 and the roller 30, which is also referred to as a pin head recess and serves, among other things, to accommodate lubricant.

The 7 and 9 show as excerpt J1 and J3 from the 5 and 6 the right side of a roller guide surface 10.3 in an enlarged scale and the 8th and 10 an enlarged section J2 and J4 from these. In the 5 and 6 the first axis of rotation 2 of the bell 10 is marked by a dash-dotted cross, from which the outer radius R10 and the inner radii R11 and R12 of the bell 10 also originate. The respective rolling circle 10.7 of the inner radii R11 and R12 is shown in the 7 and 9 represented by a dash-dotted circumferential line. The tangent to the rolling circle 10.7 forms the axis of symmetry of the roller guide surface 10.3 of the bell 10 and represents the projected bell PCD 10.8. The radial offset s1 between the two radius centers 10.4 and 10.5 determines the osculation that occurs when the outer ring of the roller 30 comes into contact with the roller guide surface 10.3 and the contact angle α ( 11 , 12 ) set.

The roller guide surface 10.3 is adjoined in the radial direction to the outside by an outer contact geometry, against which the rollers 30 rest at least partially with their radially outer end face. This radially outer contact geometry is determined in a first variant of the track of the bell 10 according to the invention based on the 7 described in more detail. As 7 As can be seen, the transition from the roller guide surface 10.3 radially outwards to the front-side system geometry is formed by a narrow flat surface 10.9 with a width s2, into which the roller guide surface 10.3 flows tangentially. The narrow flat surface 10.9 is followed by a concavely curved surface 10.10 with a radius R15, which merges into a flat surface 10.11 that is slightly inclined at an angle γ with respect to an orthogonal to the axis of rotation of the respective roller 30, which is many times wider than the above-mentioned narrow flat surface 10.9 and in turn flows into the free space 10.6 via a convexly curved transition surface a 10.12 with a radius R16. The ideal angle was an angle γ = 2°. In the unloaded state, a theoretical outer starting point 10.13 of the outer front surface of the roller 30 is located at the transition of the inclined flat surface 10.11 into the convexly curved transition surface a 10.12, which passes directly or, as will be described below, via a combination of oppositely curved surfaces into the free space 10.6 ( 11 ).

The two 7 and 9 further show an additional advantageous embodiment of the invention, in which the convexly curved transition surface a 10.12 leading into the free space 10.6 is followed by a combination of oppositely curved surfaces, which are connected by a partial surface a 10.14 convexly curved with a radius R17. and a transition surface a 10.15 with a radius R18 is formed in the opposite direction, i.e. concavely curved, so that the end of the system geometry passes into the free space 10.6 through a turning point geometry without a step, created by the sequence of a convex and concave radius R17 and R18. This enlargement of the pin head recess created in this way offers the tripod star 20 sufficient free space when it is immersed in the bell 10 and an additional reservoir for lubricant, which is conveyed into the contact area between the bell 10 and the roller 30 by the up and down movement of the tripod star 20 and thus ensures improved friction conditions.

The radially inward transition of the roller guide surface 10.3 into the clamping diameter surface 10.2 of the bell 10 is usually formed by a convexly curved transition surface b 10.16 with a radius R19 ( 9 ). In contrast, in the 7 shown variant of the radial outer contact geometry of the bell 10, the transition from the roller guide surface 10.3 into the clamping diameter surface 10.2 of the bell 10 with the smaller inner radius R12 in a variant according to the invention, as can be seen from 8th visible, divided into three partial surfaces with a radius combination. Immediately adjacent to the roller guide surface 10.3 is a convexly curved partial surface b 10.17 with a radius R20, which in turn passes over a concavely curved partial surface b 10.18 with a radius R21 into the convexly curved transition surface b 10.16 already known from the prior art. This created a secondary starting geometry for the rollers 30, ie the rollers 30, especially when bent, also have an inner starting point 10.19 ( 12 ). The first two oppositely curved partial surfaces b 10.17 and 10.18 form a relief as auxiliary surfaces and serve to ensure freedom of movement between roller 30 and bell 10. The inner starting point 10.19 ( 12 ). In this example, all three radii are calculated using the formula $$\text{R}19=\text{R}20=\text{R}21\left(2*\text{Bells}-\text{PCD}\right)/51.$$

Due to the additional, inner starting point 10.19, the tilting kinematics of the roller 30 changes when the rolling direction changes, which has a positive effect on the periodic NVH excitations of the tripod constant velocity joint, since unfavorable friction conditions are avoided.

In the 9 and 10 a second variant of the radial outer contact geometry of the raceway of the bell 10 according to the invention is described in more detail. In this variant, instead of the narrow flat surface 10.9, a partial surface aa 10.20 with a radius R22 is provided, which is convexly curved and directly adjoins the roller guide surface 10.3 and immediately merges into the surface 10.10 with a radius R15, which in turn merges tangentially into the flat surface 10.11 which is slightly inclined at an angle γ with respect to an orthogonal to the axis of rotation of the respective roller 30. In this variant, too, the transition from the last-mentioned slightly inclined flat surface 10.11 into the free space 10.6 can take place via the transition surface a 10.12, which is convexly curved with the radius R16, or in the alternative variant mentioned above via the oppositely curved surface combination 10.14, 10.15 into the free space 10.6. The two consecutive oppositely curved partial or transition surfaces aa 10.20 and 10.10 thus form a turning point, similar to the previously mentioned alternative design of the transition into the free space 10.6, so that the roller guide surface 10.3 can transition tangentially continuously, i.e. without a step, into the slightly inclined flat surface 10.11. As already mentioned above, the ideal inclination of the flat surface 10.11 was an angle γ = 2°. This also allows the radius R15 of the concave curved surface 10.10 to be increased beyond R15 = 3 mm.

The 11 and 12 show the same section of bell 10 as in the first variant of the 7 and the second variant of the 9 , but now each with a section of a roller 30, without this being described in more detail here, with the position of the roller 30 in the unloaded state, i.e. without an applied torque, being shown centered in the raceway of the bell 10. The smallest radial distance, related to the axis of rotation of a roller 30, between the contact geometry of the bell 10 and the circumferential surface of the outer ring 30.2 of the roller 30 is the radial raceway clearance δ ₁ /2, which largely determines the maximum tilting and pitching movement of the roller 30. Under load, i.e. with a torque applied to the first and/or second shaft 4, a supporting contact between the rollers 30 and the bell 10 occurs within the starting geometry of the bell 10 in the area of the transition from the inclined flat surface 10.11 to the adjoining convexly curved transition surface a 10.12, which in the 11 and 12 is identified as the outer starting point 10.13 and has a distance s3 from the axis of rotation of the rollers 30. In spatial terms, the outer starting point 10.13 is not necessarily located in the section plane shown in section J6, but can move in the plane of its front surface depending on the pitching movement of the rollers 30. Sometimes there are two contact points per half of the track, each parallel to the Cutting plane shifted. The distance between the outer starting points 10.13 per raceway is set at 0.29 times the maximum diameter of the outer ring 30.2 of the roller 30. Depending on the roller class, this value can deviate by +/-1.5%.

angestrebt.The smallest axial distance between the contact geometry of the bell 10 and the front surface of the outer ring 30.2 of the roller 30 is the frontal or axial raceway clearance δ ₂ . In order to achieve a low axial force excitation in the tripod constant velocity joint, the radial and axial raceway clearances are each $${\mathrm{\delta }}_1={\mathrm{\delta }}_2=\text{tan}\left(0.46°\right)*\text{s}3$$

aimed at.

The two smallest distances between roller 30 and roller guide surface 10.3 are offset by the contact angle α. When a torque is applied, mechanical contact occurs here and thus the actual power transmission. The larger the contact angle α, the greater the roller-centering effect when the joint is bent. At the same time, friction peaks are prevented and higher NVH emissions are thus avoided. With a selected contact angle α of 21°, the best compromise between strength, longitudinal guidance, service life and NVH behavior is achieved. If the contact angle α is too large, the contact ellipse migrates over the roller edge, i.e. the transition from the running surface to the front surface of the roller 30, more precisely in the transition from its spherical main transmission surface 30.5 to the inclined flat surface 30.7 or first flat partial surface 30.7a ( 20 - 23 ), which leads to edge wear and consequently to undesirable NVH behavior.

In the variant according to the invention of the transition from the roller guide surface 10.3 to the clamping diameter surface 10.2 of the bell 10, the two additional, oppositely curved partial surfaces b 10.17 and 10.18 cause a displacement of the convexly curved transition surface b 10.16 in the direction of the first axis of rotation 2 of the tripod constant velocity joint, i.e. the axis of rotation of the bell 10, whereby its inner radius R12 is reduced in comparison to the first variant. There is a raceway clearance δ ₃ between the convexly curved transition surface b 10.16 and the inward-facing part of the running surface of the outer ring 30.2 of the roller 30, with the roller 30 touching the raceway of the bell 10 while flexing in this distance range, so that a second, namely an inner starting point 10.19 is created. A more detailed description of the contact points on the running surface of the outer ring 30.2 of the roller 30 is given in its description based on the 20 - 23 . The target value for the smallest raceway clearance δ ₃ at the inner starting point 10.19 is 0.8 * δ ₂ in the present example.

One criterion for a favorable compromise between functionality and manufacturing effort is the osculation reciprocal, which is calculated from the quotient of the radius R13 of the roller guide surface 10.3 and the inner radius R31 of the inner ring of the roller 30 (R13/R31). In the present example, an osculation reciprocal of 1.14 was selected. This means that the contact surface is sufficiently large and at the same time the requirements for the manufacturing accuracy of the raceway of the bell 10 are more moderate than with an osculation reciprocal closer to 1.

The second essential part of the invention belonging to the tripod constant velocity joint 1 is the 13 and 14 shown inner joint part, also called tripod star 20. It consists of a cylindrical star hub 20.1 with an inner bore, which is provided with an internal toothing 20.2 for the rotationally fixed reception of the second shaft 4. Three pins 20.3 extend radially outwards from the outer casing of the star hub 20.1 at equal angular intervals of 120°, whereby each pin 20.3 has a pin head 20.4, which passes into the star hub 20.1 via a pin neck 20.5 that is reduced compared to the diameter of the pin head 20.4. The shape of the pin head 20.4 corresponds to that of a spherical segment with a radius R24 ( 15 o .19). A transition contour is provided at each transition from the tenon neck 20.5 to the tenon head 20.4 and to the star hub 20.1, whereby the radius of the transition contour to the star hub 20.1 is 2-3 times larger than the radius of the transition contour to the tenon head 20.4. This contributes to optimizing the stress in this transition area while ensuring a maximum bending angle of 26°.

At the journal head 20.4, the transmission of the torque from or to the second shaft 4 takes place at diametrically opposed torque-transmitting surfaces 20.6, namely via the inner ring of the rollers 30, which will be described in more detail below. To optimize the transmission of the torque, in particular with regard to NVH emissions, it is already known to flatten the journal heads 20.4 at the diameter areas parallel to the second axis of rotation 3 of the second shaft 4, i.e. those that are 90° to the torque-transmitting surfaces 20.6. As can be seen from the sectional view AA in 15 As can be seen, this flattening of the spherical segment is designed according to the invention as an elliptical flattening 20.7, the large semi-axis 20.8 of which runs orthogonally to the second axis of rotation 3 of the tripod constant velocity joint 1, which is also the axis of rotation of the tripod star 20. and has a length a25, which, however, cannot be measured on the component itself. The small semi-axis running orthogonally to the large one is marked with 20.9 and its smaller length with b25, which, in contrast to the length a25, can be measured on the component. In practical application, it has been shown that an optimum in terms of stress optimization in the direction of rotation and the above-mentioned maximum bending angle β of the tripod sliding joint 1 of β = 26° can be achieved by making the large semi-axis 20.8 between 8.5% and 8.6% larger than the small semi-axis 20.9. The circular circumference of the pin head 20.4 is interrupted in two diametrically opposed areas by the elliptical flattening 20.7. The width of the elliptical flattening 20.7 is marked with s4 ( 16 ). This is mainly determined by the length a25 of the major semi-axis 20.8. The center of the spherical segment from which the radius R24 originates also determines the size of the PCD of the tripod star 20, which can deviate by up to +/- 1.6% from the PCD of the bell 10. In particular, when using low-performance greases as lubricating greases, there are advantages with a smaller tripod star PCD with regard to the self-induced axial force.

In 16 an enlarged section K1 of the elliptical flattening 20.7 is shown. The rough surface created by forming during the manufacture of the tripod star 20 is set back for any subsequent fine machining.

The sectional view BB in 17 shows a section BB through the tenon neck 20.5 of the tripod star 20, which in the present example is elliptical with a major semi-axis a26 running perpendicular to the axis of rotation and a minor semi-axis b26 running parallel to the axis of rotation.

18 shows a vertical section CC along the axis of rotation 3 of the tripod star 20, which also intersects the elliptical flattening 20.7, so that the two outer edges of the pin head 20.4 reveal the contour of the flattening 20.7. In the adjacent 19 In the magnification K2 of this area of the tenon head 20.4 shown, the circumference of the spherical segment of the tenon head 20.4 is marked by a dash-dotted line and its associated radius R24. The reduction of the radius of the tenon head 20.4 in this area by the elliptical flattening 20.7 by the amount δ ₄ /2 is clearly visible.

The third component of the tripod sliding joint 1 are the rollers 30, which essentially represent the link for the transmission of the torque between the bell 10 and the tripod star 20. From the inventive features of the bell 10 described above, it is easy to conclude that the inventive features of the rollers 30 essentially relate to their track, which is in contact with the roller guide surface 10.2 of the bell 10 in the operating state. A roller consists of an inner ring 30.1 with an inner diameter D31 and an outer ring 30.2 with an outer diameter D32. The inner ring 30.1 receives the pin head 20.4 of the tripod star 20 with its inner diameter D31 and is rotatably mounted in the outer ring 30.2 via needles 30.3 evenly distributed over its outer circumference. A spring ring 30.4 is arranged on both sides of the end faces of the needles 30.3 and the inner ring 30.1, which allows an axial movement between the inner and outer rings 30.1, 30.2 within a defined clearance, whereby the predominant translational movement takes place between the inner ring 30.1 and the torque-transmitting surface 20.6 of the pin heads 20.4.

The raceway of the outer ring 30.2 consists of a spherical main transmission surface 30.5 and auxiliary surfaces symmetrically adjacent on both sides in the axial direction, which merge into the respective end face 30.6 of the outer ring 30.2. In a known manner, the auxiliary surface for increasing the bending angle of the tripod joint consists of a flat surface 30.7 inclined at an angle ε to the roller axis, which represents a "hard" transition from the spherical main transmission surface 30.5 to the respective end face 30.6. In the present example, the angle ε = 35°. When bent, the inclined flat surface 30.7 comes into contact with the starting geometry of the bell 10. In order to optimize this contact, as can be seen from the 20 and 21 As can be seen, in a basic variant of the modification of the raceway of the outer ring 30.2 according to the invention, the sharp-edged transitions from the main transfer surface 30.5 into the inclined flat surface 30.7 are each provided with a radius contour which, in the present example, is formed from a first transition radius R33a and a second transition radius R33b immediately adjacent to this, and from the inclined flat surface 30.7 into the respective end face 30.6 with a further radius contour which is formed from a first transition radius R34a and a second transition radius R34b immediately adjacent to this. Here, the first transition radius R33a from the spherical main transfer surface 30.5 to the inclined flat surface 30.7 is the largest radius at > 1.5 mm, while both the first transition radius R34a from the inclined flat surface 30.7 to the second transition radius R34b and the two second transition radii R33b and R34b are significantly smaller at < 0.1 mm. This means that A lower frictional behavior is achieved under bending, which has a positive effect in terms of reducing the axial force excitation.

In the 22 and 23 a first variant is shown, resulting from further optimization of the transitions from the spherical main transfer surface 30.5 to the end surfaces 30.6. In this variant, the inclined flat surface 30.7 is divided into two flat partial surfaces 30.7a and 30.7b, so that the flat partial surface 30.7b that transitions into the respective end surface 30.6 forms a smaller angle ε' to the end surface 30.6, in the present example of 20°. The transitions from the spherical main transfer surface 30.5 into the first flat partial surface 30.7a and from the second flat partial surface 30.7b into the respective end surface 30.6 are each rounded with a transition radius R33 or R34, since this area was identified as the main cause of undesirable NVH excitations in the contact of the rollers 30 with the bell 10.

All features presented here can be essential to the invention both individually and in any combination with one another.

Reference number list

1

Tripod constant velocity joint

2

First axis of rotation

3

Second axis of rotation

4

Second wave

α

Contact angle

β

Bending angle

γ

Angle of inclined flat surface 10.10

δ1

radial raceway clearance

δ2

axial raceway clearance

δ3

Running track game at the inner starting point 10.18

δ4

Reduction of the diameter of the pin head 20.4

ε

Angle of the inclined flat surface 30.7 to the front surface 30.6 of the scooter 30

'

Angle of the second flat partial surface 30.7b to the front surface 30.6 of the roller 30

10

Bell jar

10.1

Approach

10.2

Clamping diameter area

10.3

Roller guide surface

10.4

First radius center

10.5

Second radius center

10.6

free space

10.7

Rolling circle of the bell

10.8

Projected Bell PCD

10.9

Narrow flat surface

10.10

Concave curved surface

10.11

Inclined flat surface

10.12

Convex curved transition surface a

10.13

External contact point

10.14

Convex curved surface a

10.15

Concave curved transition surface a

10.16

Convex curved transition surface b

10.17

Convex curved surface b

10.18

Concave curved surface b

10.19

Inner contact point

10.20

convex curved surface aa

R10

Outer radius

R11

Inner radius first variant

R12

Inner radius second variant

R13

Radius of the roller guide surface 10.3

R14

Path base fillet radius

R15

Radius of the concave curved surface 10.10

R16

Radius of the convex curved transition surface a 10.12

R17

Radius of the convex curved surface a 10.14

R18

Radius of the concave curved transition surface a 10.15

R19

Radius of the convex curved transition surface b 10.16

R20

Radius of the convex curved surface b 10.17

R21

Radius of the concave curved surface b 10.18

R22

Radius of the convex curved surface aa 10.20

s1

Radial offset of radius centers 10.4 and 10.5

s2

Width of narrow flat surface 10.9

s3

Distance of the outer starting point 10.13 from the rotation axis of the roller 30

20

Tripod star

20.1

Hub body

20.2

Internal gearing

20.3

cone

20.4

tenon head

20.5

Tenon neck

20.6

Torque transmitting area

20.7

Flattening of the tenon head 20.4

20.8

Semi-major axis of the elliptical flattening 20.7

20.9

Minor semi-axis of the elliptical flattening 20.7

R24

Radius of the spherical segment of the pin head 20.4

a25

Length of the major semi-axis of the elliptical flattening 20.7

b25

Length of the minor semi-axis of the elliptical flattening 20.7

a26

Length of the major semi-axis of the tenon neck 20.5

b26

Length of the minor semi-axis of the tenon neck 20.5

s4

Width of elliptical flattening 20.7

30

Scooters

30.1

Inner ring

30.2

Outer ring

30.3

Needles

30.4

Spring ring

30.5

Spherical main transmission surface

30.6

Face of the outer ring

30.7

Sloping flat surface

30.7a

First flat surface

30.7b

Second flat surface

D31

Inner diameter of the inner ring

D32

Outer diameter of the outer ring

R33

Transition radius from main transfer surface 30.5 to first flat partial surface 30.7a

R33a

First transition radius from main transfer surface 30.5 to second transition radius R33b

R33b

Second transition radius from first transition radius R33 to inclined flat surface 30.7

R34

Transition radius from second flat partial surface 30.7b to end face 30.6 of outer ring 30.2

R34a

First transition radius from inclined flat surface 30.7 to second transition radius R34b

R34b

Second transition radius from first transition radius R34a to end face 30.6 of outer ring 30.2

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• DE 102013106868 B3 [0002, 0004]
• WO 2019/059204 A1 [0003, 0004]
• WO 9007067 A1 [0004]
• DE 4439965 A1 [0005]
• DE 4305278 C1 [0005]
• DE 4327606 C2 [0005]
• DE 102020212991 A1 [0007]

Claims (21)

Outer joint part for a sliding joint of the tripod type in the form of a cylindrical bell (10) rotating about a first axis of rotation (2) and connected in a rotationally fixed manner to a first shaft, in which an inner joint part in the form of a tripod star (20) rotating about a second axis of rotation (3) and connected in a rotationally fixed manner to a second shaft (4) is arranged so as to be axially displaceable via rollers (30) and with its axis of rotation (3) so as to be angularly movable relative to the first axis of rotation, the bell (10) having on its inner circumference a cylindrical clamping diameter surface (10.2) with a clamping diameter radius (R11, R12) which is interrupted by three guide grooves arranged at equal angular distances from one another and running parallel to the first axis of rotation (2) for receiving the rollers (30), each guide groove having two roller guide surfaces (10.3) opposite one another in the roller plane, an outer contact geometry adjoining this in a radial direction towards the outside, on which the rollers (30) rest with their radially outer Front face (30.6) at least partially abuts an outer contact point (10.13), and each roller (30) has a free space (10.6) opposite the radially outer front face (30.6), and wherein the roller guide surfaces (10.3) are formed from two concave partial surfaces, each with the same radii (R13), as seen in cross section perpendicular to the first axis of rotation, which in turn are connected to one another via a track base rounding with a track base rounding radius (R14), and pass in the radial direction inwards via a transition surface b (10.16) convexly curved with a radius (R19) into the clamping diameter surface (10.2), characterized in that the radial outer contact geometry consists of a flat surface (10.11) slightly inclined at an angle (γ) with respect to an orthogonal to the axis of rotation of the respective roller (30) and a flat surface (10.11) extending in the direction of the axis of rotation of the respective roller (30) and having a Radius (R16) convexly curved transition surface a (10.12), and that the opposite side of the inclined flat surface (10.11) merges into the roller guide surface (10.3) via a surface (10.10) concavely curved with a radius (R15). Outer joint part after Claim 1 , characterized in that the angle (γ) is approximately 1° to 3°. Outer joint part after Claim 1 or 2 , characterized in that the horizontal distance (s3) of the outer starting points (10.13) to the axis of symmetry bisecting the raceway per raceway is 0.29 times the diameter (D32) of the outer ring (30.2) of the roller (30). Outer joint part after Claim 1 , 2 or 3 , characterized in that a narrow flat surface (10.9) is arranged between the concavely curved surface (10.10) and the roller guide surface (10.3). Outer joint part after Claim 1 , 2 or 3 , characterized in that a convexly curved partial surface aa (10.20) is provided between the concavely curved surface (10.10) and the roller guide surface (10.3). Outer joint part according to one of the Claims 1 until 5 , characterized in that the convexly curved transition surface a (10.12) extending in the direction of the axis of rotation of the respective roller (30) is divided into two convexly curved transition or partial surfaces a (10.12, 10.14) with a radius (R16, R17), and the transition into the free space (10.6) is formed by an additional concavely curved transition surface a (10.15) with a radius (R18). Outer joint part according to one of the Claims 1 until 6 , characterized in that the convexly curved transition surface b (10.16) with the radius (R19) which merges inwards in the radial direction into the clamping diameter surface (10.2) is divided into three partial surfaces, wherein a concavely curved partial surface b (10.18) with a radius (R21) is arranged between the two convexly curved transition or partial surfaces b (10.16, 10.17) with the radii (R19 and R20). Outer joint part after Claim 7 , characterized in that the radii (R19, R20 and R21) of the three curved transition or partial surfaces (10.16, 10.17 and 10.18) are equal and are calculated according to the formula $$\text{R}19=\text{R}20=\text{R}21=\left(2*\text{Bell PCD}\right)/51$$

calculate. Outer joint part according to one of the Claims 1 until 8th , characterized in that the radial raceway clearance (δ ₁ ) between the roller guide surface (31) of the bell (10) and the outer ring (30.2) of the roller (30) and the axial raceway clearance (δ ₂ ) between the contact surface of the bell (10) in the region of its radial outer contact geometry and the outer end face of the roller (30) are determined according to the formula $${\mathrm{\delta }}_1={\mathrm{\delta }}_2=\text{tan}\left(0.46°\right)*\text{s}3$$

calculate. Outer joint part according to one of the Claims 7 until 9 , characterized in that the barrel track clearance (δ3) between the contact surface of the bell (10) in the area of the three curved partial or transition surfaces (10.17, 10.18 and 10.16), i.e. in the area of the inner contact point (10.19), and the outer ring (30.2) of the roller (30) is a maximum of 0.8 times the track clearance (δ2). Inner joint part for a sliding joint of the tripod type in the form of a tripod star (20) rotating about a second axis of rotation (3) and connected to a second shaft (4) in a rotationally fixed manner, which is arranged in an outer joint part in the form of a bell (10) in an axially displaceable manner via rollers (30) and with its axis of rotation (3) angularly movable relative to a first axis of rotation (2), wherein the tripod star (20) has three pins (20.3) directed radially outwards from its star hub (20.1) at equal angular distances from one another, which consist of a pin neck (20.5) and a spherical segment-shaped pin head (20.4) which is flattened on two diametrically opposite and 90° to the spherical torque-transmitting peripheral regions (20.6) and, in the assembled state of the sliding joint, accommodates a roller (30) with its inner ring (30.1) in an angularly movable manner, wherein the radius (R24) of the spherical segment corresponds to half the value of the inner diameter (D31) of the inner ring (30.1) of the roller (30), so that the transmission of the torque takes place via the spherical circumferential regions of the pin head (20.4), hereinafter referred to as torque-transmitting surfaces (20.6), characterized in that the flattening of the spherical segment is designed as an elliptical flattening (20.7), the major semi-axis (20.8) of which runs orthogonal to the axis of rotation (3) of the tripod star (20). Inner joint part after Claim 11 , characterized in that the pitch circle diameter (PCD) of the spherical segment-shaped pin heads (20.4) deviates by up to +/- 1.6% from the PCD of the bell (10). Inner joint part after Claim 12 , characterized in that the pitch circle diameter (PCD) of the spherical segment-shaped pin heads (20.4) is smaller than PCD of the bell (30). Inner joint part according to one of the Claims 11 until 13 , characterized in that the small semi-axis (20.9) of the elliptical flattening (20.7) is b25 = (0.990 to 0.992) * R24 and the large semi-axis (20.8) of the elliptical flattening (20.7) is a25 = (1.20 to 1.21) * R24. Method for producing an inner joint part for a sliding joint of the tripod type in the form of a tripod star (20) rotating about an axis of rotation (3) and connected to a shaft (4) in a rotationally fixed manner, which has three pins (20.3) directed radially outwards from its star hub (20.1) at equal angular distances from one another, which consist of a pin neck (20.5) and a spherical segment-shaped pin head (20.4) with a radius (R24) which is flattened on two diametrically opposite and 90° to the torque-transmitting surfaces (20.6) and is produced by forming, characterized in that the flattening of the spherical segment is designed as an elliptical flattening (20.7) whose major semi-axis (20.8) runs orthogonal to the axis of rotation (3) of the tripod star (20), wherein this flattening (20.7) of the spherical segment in the blank perpendicular to the clamping plane of the ellipse and following the course of the sphere radius (R24), it is already finished in the forming process, then the end faces of the star hub (20.1) and its internal teeth (20.2) are finished by material-removing machining, then the tripod star (20) is hardened and finally the torque-transmitting surfaces (20.6) are finished by material-removing hard machining in a rotationally symmetrical manner to the respective pin (20.3). Roller (30) for a sliding joint of the tripod type, which consists of an outer joint part in the form of a cylindrical bell (10) rotating about a first axis of rotation (2) and connected to a first shaft in a rotationally fixed manner, on the inner circumference of which there are three guide grooves arranged at equal angular distances from one another, running parallel to its axis of rotation (2) and extending radially outwards, and an inner joint part in the form of a tripod star (20) rotating about a second axis of rotation (3) and connected to a second shaft (4) in a rotationally fixed manner, which has three pins (20.3) directed radially outwards from its star hub (20.1) at equal angular distances from one another, on the pin head (20.4) of which a roller (30) consisting of an inner ring (30.1) and an outer ring (30.2) rotatably connected to it via rolling elements (30.3) is arranged in an angularly movable manner, wherein the inner joint part in the assembled state can be moved by means of the rollers (30) is guided axially displaceably in the said guide grooves of the bell (10) and the outer raceway of the outer ring (30.2) of each roller (30) comes at least partially into contact with the inner raceways of the guide grooves, wherein the outer raceway of each roller (30) has a spherical peripheral region as the main force transmission surface (30.5), which merges via at least one modified auxiliary surface into the outer and inner end face (30.6) of the outer ring (30.2) of the roller (20), characterized in that the transition from the spherical spherical main force transmission surface (30.5) to the outer and inner end faces (30.6) is formed by a flat surface (30.7) and at the respective transition from the spherical main force transmission surface (30.5) to the flat surface (30.7) at least one transition radius (R33a, R33b) is provided and from the flat surface (30.7) to the outer and inner end faces (30.6) at least one transition radius (R34a, R34b) is provided. Scooter to Claim 16 , characterized in that the transition radii (R33a, R34b) are greater than 1.5 mm. Scooter to Claim 16 , characterized in that the transition radii (R33b; R34a) are smaller than 0.1 mm. Scooter to Claim 16 , characterized in that the flat surface (30.7) is divided into two flat partial surfaces (30.7a and 30.7b), wherein the second flat partial surface (30.7b) seen in the axial direction merges via a radius (R34) into the respective end face (30.6) of the outer ring (30.2) of the roller (30). Scooter to Claim 19 , characterized in that the respective first flat partial surface (30.7a) is inclined by 35° and the respective second flat partial surface (30.7b) is inclined by 20° with respect to the respective end face (30.6). A sliding joint of the tripod type for an automotive drive train, comprising - an outer joint part in the form of a cylindrical bell (10) rotating about a first axis of rotation (2) and connected to a first shaft in a rotationally fixed manner, which has guide surfaces arranged at equal angular distances from one another and running parallel to the first axis of rotation (2) on its inner circumference, and/or - an inner joint part in the form of a tripod star (20) rotating about a second axis of rotation (3) and connected to a second shaft (4) in a rotationally fixed manner, from which pins (20.3) extend radially outwards at equal angular distances from one another, the free ends of which are designed as spherical sections, and/or - three rollers (30), one of which is arranged on a pin (20.3) of the tripod star (20) so as to be rotatable and pivotable relative to the axis of rotation (3) of the tripod star (20) and, in the assembled state, so as to be longitudinally displaceable in a guide groove of the bell (10), characterized that the bell (10) has the characteristics of Claims 1 or 2 until 10 and/or that the tripod star (20) has the features of Claims 11 or 12 until 14 and/or that the scooter (30) has the features of the Claims 16 or 17 until 20 having.