DE102022104653A1 - Tripod roller for a constant velocity joint with friction reduction and constant velocity joint with the tripod roller - Google Patents

Abstract

Constant velocity joints are used to transmit torque and are designed as joints, so that a uniform transmission of angular velocity and torque can take place from one shaft to another shaft that is at least temporarily attached at an angle thereto. A tripod roller 9 for a constant velocity joint 1 is proposed with an inner ring 11 and with an outer ring 12 as rings, with a plurality of rollers 13, with the rollers 13 being arranged to roll between the rings, with a side disk 18 as a stop for the rollers 13 in the axial direction, with the side disk 18 having a contact surface 20 for the rollers 13, with the contact surface 20 being designed as a circular ring, with the side disk 18 being designed such that a circular ring width 21 of the circular ring is smaller than the diameter 22 of the rollers 13 is.

Description

The invention relates to a tripod roller for a constant velocity joint with the features of the preamble of claim 1. The invention also relates to a constant velocity joint with the tripod roller.

Constant velocity joints are used to transmit torque and are designed as joints, so that a uniform transmission of angular velocity and torque can take place from one shaft to another shaft that is at least temporarily attached at an angle thereto. For example, constant velocity joints are used to transfer drive torque from an engine to the wheels of a steered axle of a vehicle.

A widespread design of constant velocity joints are tripod joints, which have a tripod spider with bolts as a joint partner, the bolts being aligned in the radial direction with respect to the joint partner and each carrying a tripod roller. The second joint partner has a joint bell, into which the tripod star engages with the tripod rollers.

For example, the reference discloses DE 10 2010 031 752 A1 , which forms the closest prior art, a tripod constant velocity joint, with an outer joint part that has a central cavity and three circumferentially equally distributed recesses emanating therefrom, each with two axis-parallel and circumferentially parallel opposing guideways. The constant velocity joint has an inner joint part which is arranged inside the cavity of the outer joint part and has three bolts with a spherical outer contour which are arranged equally distributed around the circumference and each project radially into one of the recesses of the outer joint part. Furthermore, the constant velocity joint has three tripod rollers, each with an inner roller ring, an outer roller ring, and a plurality of cylindrical rolling bodies arranged in a ring between the roller rings, the inner wall of the respective inner roller rings being in sliding contact with the outer contour of the associated bolt, and the respective outer roller rings with their Outer wall are in sliding contact with the guideways of the associated recess. The friction and wear properties of the constant velocity joint are improved by appropriate surface treatment of the walls in sliding contact with each other.

It is the object of the present invention to propose a tripod roller which has reduced friction during operation. This object is achieved by a tripod roller with the features of claim 1 and by a constant velocity joint with the tripod roller with the features of claim 9. Preferred or advantageous embodiments of the invention result from the dependent claims, the following description and the attached figures.

The subject matter of the invention is therefore a tripod roller for a constant velocity joint. The constant velocity joint is designed in particular as a constant velocity plunging joint. In particular, the constant velocity joint is designed as a homokinetic joint for uniform angular velocity and torque transmission from one shaft to a second shaft attached at an angle thereto. The constant velocity joint is particularly preferably designed as a transmission joint for transmitting a drive torque from an engine to steered wheels of a vehicle. In particular, the constant velocity joint is arranged between an axle drive and a drive shaft.

As a first joint partner, the constant velocity joint has a tripod star with three journals extending in the radial direction to an axis of the tripod star. A corresponding tripod roller is placed on each pin. The tripod star engages in a joint bell as the second joint partner, the joint bell having three elongated recesses running in the axial direction toward the second joint partner, into which the three tripod rollers can move axially toward the second joint partner.

The tripod roller has an inner ring to be placed on the tripod star, in particular on one of the journals of the tripod star. Furthermore, the tripod roller has an outer ring, the outer ring being arranged coaxially to the inner ring. In the following, the inner ring and outer ring are collectively referred to as rings. The rings are also arranged coaxially to a tripod roller axis. The outer ring preferably has a crowned and/or spherical segment-like outside in a longitudinal section along the tripod roller axis. The outer ring has an outer raceway for the rollers, and the inner ring has an inner raceway for the rollers. The raceways are preferably formed by a base body of the respective ring.

The tripod roller has a plurality of rollers, in particular cylindrical rollers, the rollers being arranged to roll between the rings. In particular, the rollers are oriented in the same direction and/or parallel to the tripod roller axis. The rollers are particularly preferably arranged in a single row.

The tripod roller has at least one side disk as a stop for the rollers in the axial direction, in particular towards the tripod roller axis. Optionally, the tripod roller has two side discs, which are arranged on both sides of the rollers. Particularly in the event that a torque is transmitted at an angle via the constant velocity joint, the rollers in the tripod roller can become interlocked, so that the rollers can run against the side window in the axial direction. A contact surface for the rollers on the side window is formed by the running of the rollers on the side window. The contact surface is designed as a circular ring due to a rotation of the rollers around the tripod roller axis.

In the context of the invention, it is proposed that the side disk is constructed in such a way that an annular width of the annular ring of the contact surface is smaller than the diameter of the rollers. In particular, the maximum diameter and/or the diameter on the adjacent end face of the rollers is used as the diameter of the rollers. As a result, the contact surface between the rollers, in particular the end faces of the rollers, and the side disk is reduced, so that the friction between the rollers and the side disk is reduced. The reduction in friction between the rollers and the side window also reduces the friction in the tripod roller and/or in the constant velocity joint.

In a preferred development of the invention, the annular width is less than 50%, preferably less than 30%, of the diameter of the rollers. By reducing the width of the circular ring to the extent claimed, a significant reduction in the contact surface and thus the friction is achieved. It can additionally be provided that the circular ring width is designed to be further reduced, so that the circular ring width is designed to be less than 10% of the diameter of the rollers, for example. In the limiting case, the circular ring width is reduced to zero or, as a real contact surface, to almost zero and/or the contact surface is formed by a linear support.

In a preferred constructional embodiment of the invention, the side window has a circumferential raised area. In particular, the raised area protrudes in the axial direction beyond the adjacent radial areas of the side window. In particular, the raised area protrudes in the axial direction beyond the adjacent radial areas of the side disk in an annular area which is formed by an axial projection of the rollers onto the side disk. It is provided that the raised area forms the contact surface. The reduced contact area is implemented constructively by the raised area. In particular, the raised area runs in a pitch circle diameter, which is defined by the axes of rotation of the rollers.

In a preferred implementation of the invention, the elevation area on the side facing the rollers is designed to be semicircular, crowned, convex and/or curved in longitudinal section. This design ensures that the width of the circular ring is further reduced or even minimized to a line-like contact surface.

In one possible embodiment of the invention, the raised area is formed by an embossing in the side window. The side disk thus has an outer radial section, a central radial section and an inner radial section, with the raised area being arranged in the central radial section and with the central radial section being raised relative to the inner and/or outer radial section in the direction of the rollers. On the other hand, it is preferably provided that on the opposite side and/or rear side of the side panel there is an embossed area of the central radial area in the circumferential direction, so that the material can flow out of the side panel in the axial direction to form the raised area.

In a preferred structural realization, the side window is designed as a continuous side ring. For example, the side ring can also be connected to a seal. However, it is preferred that the side window is designed as a snap ring, with the snap ring having at least one separation point in the circumferential direction. In particular, the snap ring is snapped into the outer ring or into the inner ring. Such a snap ring with a raised area is inexpensive to manufacture and allows an improvement in terms of the friction of the tripod roller.

It is particularly preferred that the rollers have a flat end face so that they can always run reliably against the contact surface. The rollers are particularly preferably designed as needles, and thus have a comparatively small maximum diameter compared to the length.

A further object of the invention relates to a constant velocity joint, which has at least one tripod roller, as described above or according to one of the preceding claims. The constant velocity joint preferably has a tripod star as a joint partner, which has three journals aligned in the radial direction to the joint partner, on each of which a tripod roller is arranged, as described above or according to one of the preceding claims. The other joint partner is, however, designed as a joint bell, which has three elongated recesses into which the tripod rollers are retracted. In particular, the constant velocity joint is designed as previously described.

• 1 eine schematische Blockdarstellung eines Fahrzeugs mit einem Gleichlaufgelenk als ein Ausführungsbeispiel der Erfindung;
• 2 eine schematische Längsschnittdarstellung einer Tripodenrolle für das Gleichlaufgelenk in der 1 als ein erstes Ausführungsbeispiel;
• 3 eine schematische, dreidimensionale Darstellung einer Seitenscheibe für die Tripodenrolle in der 2.

Further features, advantages and effects of the invention result from the following description of a preferred exemplary embodiment of the invention and the attached figures. show:

• 1 a schematic block diagram of a vehicle with a constant velocity joint as an embodiment of the invention;
• 2 a schematic longitudinal sectional view of a tripod roller for the constant velocity joint in 1 as a first embodiment;
• 3 a schematic, three-dimensional representation of a side window for the tripod roller in the 2 .

The 1 shows a highly schematic representation of a constant velocity joint 1 for a vehicle 2, which is only shown as a block, as an embodiment of the invention.

The constant velocity joint 1 is arranged in the drive train between a transmission output 3, in particular a differential gear, and an intermediate shaft 4, in particular a wheel drive shaft or a cardan shaft. The transmission output 3 defines an output axis 5, the intermediate shaft 4 defines a shaft axis 6. The constant velocity joint 1 is designed to transmit a rotation and thus a drive torque from the output 3 to the intermediate shaft 4 and at the same time a pivoting or angle change between the output axis 5 and the To allow shaft axis 6, as can be done, for example, in a compression of the connected to the intermediate shaft 4, driven wheel. The intermediate shaft 4 has a stub shaft section 7 on which a plurality of journals 8 , in this exemplary embodiment three journals 8 , are arranged, which extend radially to the shaft axis 6 . The pins 8 are arranged regularly around the shaft axis 6 in the direction of rotation, so that they form a tripod star. In the 1 only one of the pins 8 is shown graphically. A tripod roller 9 is arranged on each of the journals 8 and has a tripod roller axis 100 as the axis of rotation, which is arranged radially with respect to the shaft axis 6 .

The constant velocity joint 1 also has a bell section 10 of a joint bell, which is coupled in a torque-proof manner to the output 3 and which provides raceways for the tripod rollers 9 .

while in the 1 an exemplary embodiment is shown, in which the bell section 10 is coupled in a torque-proof manner to the output 3 and the stub shaft section 7 is coupled in a torque-proof manner to the intermediate shaft 4, it is also possible in other exemplary embodiments that the stub shaft section 7 is coupled in a torque-proof manner to the output 3 and the bell section 10 is coupled to the intermediate shaft 4. It is also possible for the bell section 10 to be closed all the way round or to have free areas.

The 2 shows the tripod roller 9 of FIG 1 . The tripod roller 9 has an inner ring 11 and an outer ring 12 which are arranged coaxially to the tripod roller axis 100 . A plurality of rolling bodies are arranged between the inner ring 11 and the outer ring 12, the rolling bodies being designed as rollers 13 and, in particular, as needles. The rollers 13 are aligned parallel to the tripod roller axis 100 . The inner ring 11 provides an inner raceway 14, the outer ring 12 provides an outer raceway 15 for the rollers 13, the rollers 13 rolling on the inner raceway 14 and outer raceway 15, respectively. The outer ring 12 is curved on the radial outside, so that it is adapted to the bell section 10 . In particular, the outer ring 12 has a circular, convex and/or crowned contour in the longitudinal sectional view shown. The inner ring 11 has a receptacle 16 for the pin 8 .

The tripod roller 9 has a side disk 18 on both sides of the rollers 13, which in this exemplary embodiment is in the form of a snap ring. The outer ring 12 has two circumferential insert grooves 19 into which the side disks 18 designed as a snap ring can be snapped, so that the side disks 18 each form a form-fit contact for the rollers 13 .

In operation, the rollers 13 run against the side disks 18 in the axial direction with respect to the tripod roller axis 100, for example when the constant velocity joint 1 does not transmit the torque with aligned axes 5, 6, but with angled shafts 5, 6.

The running of the rollers 13 against the respective side window 8 forms a contact surface 20 for the rollers 13 on the side of the side window 18 facing the rolling elements 13 . Due to the rotation of the rolling bodies 3 about the tripod roller axis 100 and the structural design of the tripod roller 9, the contact surface 20 is designed as a whole as a circular ring.

As can be seen from the illustration in the 2 results, an annulus width 21 of the annulus is formed significantly smaller than the diameter 22 of the rollers 13. The annulus of the contact surface 20 is particularly preferably adapted with a center line of the annulus to the pitch circle diameter of the roller axes of the rollers 13, so that the rollers 13 when starting the side discs 18 pierce the circular ring with their respective roller axis, in particular in the middle. In this way, the friction of the rollers 13 on the side windows 18 is reduced.

The reduction in the annular width 21 of the annular ring of the contact surface 20 in comparison to the diameter 22 of the rollers 13 is achieved by a circumferential raised area 23 of the side disk 18, the raised area 23 being arranged in a radial middle region of the side disk 18 and opposite a radial inner region 24 ( 3 ) and a radial outer area 25 ( 3 ) of the side window 18 is raised.

The main body of the side window is rectangular in the longitudinal section shown, with the raised area 22 protruding from the rectangular shape on the side facing the rollers 13 . In the longitudinal section shown, the raised area 22 has a crowned, convex and/or curved shape, so that the contact surface 20 is reduced to a very narrow circular ring. The friction of the rollers 13 on the side windows 18 is greatly reduced by this greatly reduced contact surface.

As emerges from the 2 results, the raised area 22 is formed by an embossing in the side window 18 . On the opposite side of the side pane 18 is shown a circumferential embossed area 26 which occurs when the raised area 23 is embossed due to the material flow in the axial direction to the tripod roller axis 100 .

The rollers 13 are designed as cylindrical rollers, in particular needles, with a flat end face, the diameter of the end face approximately corresponding to the diameter 22 of the rollers 13 . This ensures that the rollers 13 run against the contact surface 20 with a flat side area.

The 3 shows a schematic, three-dimensional representation of the side disk 18 designed as a snap ring. A separation point 27 can be seen, which makes it possible to briefly reduce the outer diameter of the side disk 18 by elastic deformation so that it can be inserted into the insert groove 19 of the outer ring 12 can. The peripheral raised area 23 can be clearly seen, which is raised compared to the rest of the side surface of the side window 18 , in particular compared to the radial inner area 24 and the radial outer area 25 .

Reference List

1

constant velocity joint

2

vehicle

3

gear output

4

intermediate shaft

5

output axis

6

shaft axis

7

stub shaft section

8th

cones

9

tripod pulley

10

bell section

11

inner ring

12

outer ring

13

roll

14

inner race

15

outer track

16

Recording

17

empty

18

side window

19

insert grooves

20

contact surface

21

annulus width

22

diameter of the rolls

23

increase range

24

radial interior

25

radial outer area

26

embossing area

27

separation point

100

tripod roller axis

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited 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 assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102010031752 A1 [0004]

Claims (9)

Tripod roller (9) for a constant velocity joint (1) with an inner ring (11) and with an outer ring (12) as rings, with a plurality of rollers (13), wherein the rollers (13) are arranged rolling between the rings, with a Side disk (18) as a stop for the rollers (13) in the axial direction, the side disk (18) having a contact surface (20) for the rollers (13), the contact surface (20) being designed as a circular ring, characterized in that that the side disc (18) is designed such that a circular ring width (21) of the circular ring is smaller than the diameter (22) of the rollers (13). Tripod roller (9) after claim 1 , characterized in that the circular ring width (21) is smaller than 50%, preferably smaller than 30% of the diameter (22) of the rollers (13). Tripod roller (9) after claim 1 or 2 , characterized in that the side window (18) has a circumferential raised area (23), the raised area (23) forming the contact surface (20). Tripod roller (9) according to one of the preceding claims, characterized in that the raised area (23) is rounded, crowned, convex and/or curved in a longitudinal section. Tripod roller (9) according to one of the preceding claims, characterized in that the raised area (23) is formed by an impression in the side panel (18). Tripod roller (9) according to one of the preceding claims, characterized in that the side disc (18) is designed as a snap ring or as a side ring. Tripod roller (9) according to one of the preceding claims, characterized in that the rollers (13) have a flat end face. Tripod roller (9) according to one of the preceding claims, characterized in that the rollers (13) are designed as needles. Constant velocity joint (1), characterized by at least one tripod roller (9) according to one of the preceding claims.

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