WO2000011363A1

WO2000011363A1 - Two-part articulated element

Info

Publication number: WO2000011363A1
Application number: PCT/EP1999/006033
Authority: WO
Inventors: Eberhard Ernst; Wolfgang Schiemenz
Original assignee: Gkn Sinter Metals Gmbh
Priority date: 1998-08-19
Filing date: 1999-08-18
Publication date: 2000-03-02
Also published as: DE19837471A1; AU5517599A

Abstract

The invention relates to a method for producing a constant velocity joint (1) comprising an outer joint segment and at least one inner joint segment (3) which has undercut areas, recesses and/or shaped sections serving as inner races and is housed in the outer joint segment. According to the invention the inner joint segment and/or the outer joint segment each consist of at least two corresponding, preferably annular joint elements (9, 9'). The invention also relates to a constant velocity joint produced according to said method.

Description

Description Two-part joint body

description

The invention relates to a method for producing a shaft joint with an outer joint part and at least one inner joint part having undercuts, recesses and / or profiles for inner ball tracks for receiving in the outer joint part.

Universal joints of this type are known. They are primarily used for torque transmission between shafts that are subject to major displacements during operation. The absorption of axial displacements is also possible.

An example of the transmission of torque via mutually angled shafts is the constant velocity universal joint. Synchronous universal joints belong to the genus of tenon joints, the most common design of which is the universal joint. In the universal joint, the joint forks of the two shafts are one

Spigot connected. Simple universal joints allow essentially small changes in angle. However, axial and radial displacements of the shafts are not possible. Furthermore, uniform speeds are generated on the output side at a uniform angular velocity. The same applies to the torques. The PTO shaft avoids these disadvantages. This consists of two joints and an intermediate shaft. The intermediate shaft is usually designed as a telescopic shaft to compensate for changes in length. A condition for uniform transmission is that the two joint forks are in one

Are level and, if the deflection angles on both joint forks are always the same size, at least in the most frequently occurring position during operation. This can be achieved by a Z or W arrangement. The former is usually common in motor vehicles. Non-uniformities only occur in the intermediate shaft. Double joints are used to compensate for large angular movements in a small space, for example in the front-wheel drive of motor vehicles. This correspond in principle to the cardan shaft, but instead of the intermediate shaft there is only a short intermediate piece - shaft or sleeve - which is guided in such a way that the deflection angles of both joints are always the same. The longitudinal displaceability is provided in the input or output shaft. In addition, constant velocity joints enable a uniform, non-positive transmission of the torque or the angular velocity mostly via balls, which are guided in ball tracks so that they always lie in the mirror plane of the joint. Centering is necessary for larger constant velocity joints. The constant velocity joints enable uniform transmission at large deflection angles. Constant velocity joints are built as fixed joints or sliding joints, whereby the fixed joint fixes the drive axis in the axial direction and the sliding joint enables compensation for changes in the length of the axle by longitudinal displacement.

Universal joints of this type are connected to the shafts with an outer joint part and an inner joint part. The inner joint part is guided by balls on the outer joint part. The balls move in a cover ring in ball tracks which are formed on the outer surface of the inner joint part and on the inner surface of the outer joint part. The geometry of the shaft joints requires that the recesses for the ball tracks be machined. This usually requires costly, high-precision, machining. The disadvantage here is that the inner joint part has to be manufactured in a large number of work steps and in different processing machines. Up to now, the inner joint part has been formed from a blank in a conventional way, since the undercuts or moldings could not be produced by the pressing process and therefore could not be pressed from metal powder and sintered to the final shape. This usually required additional process steps to achieve the shape of the undercuts. The object of the invention is to provide a method with which a shaft joint can be produced in a simple manner, in particular a synchronous shaft joint is made available which is accessible to simple pressing methods due to its geometry.

The object is achieved in that the inner and / or outer joint part is composed of at least two corresponding, preferably annular joint bodies. The invention is based on the fact that a body with a complex geometry can be divided into one or more bodies with a simpler geometry by one or more cuts. In the case of the present inner and / or outer joint part, it is provided that the geometry of the individual joint bodies is designed in such a way that at least two essentially identical joint bodies with easy-to-press geometry can be arranged with their respective contact surfaces in such a way that a Joint inner and / or outer joint part with corresponding complex geometry arises.

It is envisaged that the joint bodies can be connected to one another by joining methods, preferably by plugging (positive locking), soldering, welding and / or sintering (material locking). It is also possible to arrange the joint bodies on the respective shaft and fasten them axially in such a way that they rest against one another without a fixed connection (positive locking) and thus form the inner joint part. According to the invention, it is provided that the joint body made of powdery material, preferably of metal powder, is pressed in a pressing device. This joint body has the advantage that when connected to a corresponding counterpart by sintering, the entire body of the inner joint part forms a high-strength structure which has excellent material properties and surface quality. Furthermore, a method is provided in which the joint bodies are pressed as a blank in a pressing device with stamps movable in the direction of the axis of the joint body. Such a pressing device is characterized by a simple working drain off. This pressing process is inexpensive and, above all, time-saving. This makes it possible to produce a large number of joint bodies or inner joint parts in a short time. The invention further relates to a method according to which the joint body is produced in one or more pressing processes. This makes it possible to make changes to the molding as well as the tool between individual pressing processes in order to use individual design options.

A further advantage is achieved by heat treatment of the joint body or of the inner and / or outer joint part. According to this, the joint bodies, inner and / or outer joint parts have appropriate strength.

It has been found to be particularly advantageous that the joint body or the joint inner and / or joint outer part are post-compressed. As a result, corresponding dimensional accuracies of the parts can be generated or irregularities in the manufacture can be eliminated.

The joint body or the inner and / or outer joint part can be produced in all conventional ways. It is provided according to the invention to press the parts out of powdery material, in particular out of metal powder. Furthermore, it is also provided that the parts are produced by forging or fine forging or by cold extrusion.

A further solution to the problem according to the invention is provided by a shaft joint, in particular a constant velocity shaft joint, with an outer joint part and an inner joint part with inner ball tracks arranged therein, which is produced by the method according to the invention. The inner and / or outer joint part is composed of joint bodies. The inner and / or outer joint part is designed with undercuts, recesses and profiles, preferably axially to the joint body axis aligned on the outer surface, radially curved ball tracks, the ball tracks are designed with a track base and track sides and the individual joint body has a geometry that makes it possible to press it axially and to remove it from the press mold of the pressing device. The joint body according to the invention is then advantageously designed with a simple geometry that can be produced by a pressing process with a pressing direction acting axially to the joint body axis. Advantageously, the joint bodies are joined together in a non-positive, material and / or form-fitting manner on the contact surfaces to form an inner and / or outer joint part. It is envisaged that the edges of the contact surfaces of the two joint bodies at least partially abut each other in the bottom of the ball tracks. The section through the inner and / or outer joint part on the contact surfaces thus runs in such a way that the abutting edges of the respective joint bodies run in the base of the ball tracks. This is advantageous when it is a question of a geometry of the ball tracks in which the ball itself does not touch the bottom of the track. This can be the case in particular in the case of polygonal cross sections of the ball tracks, but also in the case of ball tracks which are elliptical in cross section.

A further embodiment is advantageous in which the edges of the contact surfaces run at least partially on the track sides or the respective track base of the ball tracks. It is particularly advantageous if the running surfaces of the ball tracks and the edges do not intersect.

In the case of the inventive universal joints, arrangements are advantageously provided which have at least three balls and which have the corresponding ball tracks. In particular, arrangements with four, five, six or seven balls are also possible.

According to the invention, provision is also made to fasten the joint bodies on the corresponding shafts by means of axial fastening means. Without additional joining processes, the joint body attached to the shaft for connection. These universal joints are particularly easy to manufacture and inexpensive, since they can be pressed in one operation and then sintered.

In the drawings, the invention is illustrated using an embodiment of a constant velocity universal joint. Show it:

1 is a constant velocity universal joint in the known embodiment,

2 shows a constant velocity shaft joint with a section through the inner joint part in each case in an angled cross section through the shaft joint,

3 an inner joint part in cross section,

3a) in plan view and

3b) perpendicular to the axis of the joint body,

3c) the joint body individually

3d) the inner joint part in plan view on one side

Fig. 4 is a ball track with ball in cross section.

1 shows a constant velocity universal joint 1. It has an outer joint part 2 and an inner joint part 3. The outer joint part 2 is connected to a shaft 4, and the inner joint part 3 is connected to a shaft 5. The shaft 4 and the shaft 5 form a drive-output system. The inner joint part 3 is received in the outer joint part 2. Balls 6 are arranged in ball tracks 7 between the outer joint part 2 and the inner joint part 3 so that the balls 6 are guided against each other in the ball tracks 7 when the shafts 4, 5 are bent. The balls inevitably run in the mirror plane. In the form shown, the angle of deflection is 0 ° and the ball lies in a plane perpendicular to the straight line formed by the axes of the shafts 4 and 5. The arrangement has a cover ring 8 which holds the ball in the ball tracks. When the drive shaft is rotated, the output shaft is transmitted at a constant speed and torque even with appropriate deflection within the possible limits. The shaft joint 1 is sealed to the outside with a flexible seal 18.

2 shows a constant velocity universal joint 1. Here, the inner joint part 3 each has a drive body 9, 9 'on the output and drive side. Depending on the design of the outer surfaces in the output or drive direction, both joint bodies 9, 9 'can be designed essentially the same. The two joint bodies are connected to one another by joining processes. Fastening on the shaft 5 is also conceivable, for example by means of fastening means such as a fastening ring and a fastening groove, the joined joint bodies being locked on the shaft. The fastening ring and fastening groove are not shown in FIG. 2.

3a) shows an inner joint part 3. The inner joint part 3 has ball tracks 7 which are assigned to one another in pairs. The ball tracks 7 are aligned axially into the image plane and have a radial curvature 14. The curvature 14 is opposed to each of the pair of ball tracks 7 assigned to one another, i. H. the ball tracks 7 run towards each other in an axial direction. The joint body axis A runs perpendicular to the image plane through the center of the joint bodies 9, 9 '

3b) shows a joint body 9, 9 'in cross section along the joint body axis A. The joint body 9 has the contact surface 10, which is attached to an opposite th joint body 9 'is brought into contact with the contact surface 10'.

3c shows the joint body 9 individually. The joint body 9 is cut so that the contact surfaces 10 lie both partially in the circumference and perpendicular to the axis of the joint body 9, i. H. is directed perpendicular to the plane of the drawing. The joint body 9 has ball tracks 7 which protrude beyond the contact surface 10. The ball tracks 7 are only half shown with a track side 13. In the assembled inner joint part, the ball tracks 7 are complete and each have track sides 13 and 13 '. The corresponding joint body 9 ', which is not shown here, would be plugged from the top opposite to the illustrated joint body 9, so that the ball tracks 7 form an edge in the track base 12.

FIG. 3d shows a sequence of a top view from the side of the inner joint part 3, which is composed of the joint bodies 9, 9 '. Here are the investment areas

10, 10 'drawn with dashed lines since they are not visible. The two joint bodies 9, 9 'each have corresponding track sides 13, 13', which form the ball tracks 7. Between the web sides 13, 13 '12 edges 19 are visible in the web base, on which the contact surfaces 10, 10' rest.

Fig. 4 shows a ball track 7 with a ball 6 in cross section. The ball 6 has a geometry that is circular. The ball track 7 has a geometry that is elliptical. The ball runs on the running surface 16, 16 'and has two contact points on the ball track at every moment. Each point of contact 17, 17 'lies on a different web side 13, 13'. Each web side 13, 13 'belongs to another joint body 9, 9'. The edges are in the bottom of the web

(12). The ball track 7 is designed so that the edges do not intersect the tread 16 of the ball 6, but always in Roll over distance d. The contact points 17, 17 'are separated from one another at an angle 2δ from the center of the sphere.

For the sake of clarity, the contact surfaces 10, 10 'of the two joint bodies 9, 9' are shown somewhat apart from one another to show that there are two joint bodies 9, 9 'which abut one another on this side.

Claims

claims

1. Method for producing a constant velocity universal joint (1) with an outer joint part (2) and at least one inner joint part (3) with undercuts, recesses and / or profiles for inner ball tracks (7) for receiving in the outer joint part (2), characterized in that the inner joint part (3) and / or the outer joint part are each composed of at least two corresponding, preferably annular joint bodies (9, 9 ').

2. The method according to claim 1, characterized in that the joint bodies (9, 9 ') are connected to one another by joining methods, preferably by form or material connection, for example soldering, welding and / or sintering.

3. The method according to one or more of the preceding claims, characterized in that the joint bodies (9, 9 ') have mutually corresponding contact surfaces (10, 10') with which the joint bodies (9, 9 ') abutting one another in the respective final shape are brought.

4. The method according to one or more of the preceding claims, characterized in that the joint body (9, 9 ') made of powdery material, preferably of metal powder, is pressed in a pressing device.

5. The method according to one or more of the preceding claims, characterized in that the joint body (9, 9 ') is pressed in the pressing device with stamps axially movable in the direction of the joint body axis.

6. The method according to one or more of the preceding claims, characterized in that the joint body (9, 9 ') is produced in one or more pressing and / or molding processes.

7. The method according to one or more of the preceding claims, characterized in that the joint body (9, 9 ') or the inner and / or outer joint part (2, 3) are sintered and / or pre-sintered.

8. The method according to one or more of the preceding claims, characterized in that the joint body (9, 9 ') or the inner and / or outer joint part (2, 3) are heat treated.

9. shaft joint (1), in particular constant velocity shaft joint, with an outer joint part (2) and an inner joint part (3) arranged therein with ball tracks (7) produced by a method according to one or more of the preceding claims, characterized in that Inner and / or outer joint part (2, 3) is composed of joint bodies (9, 9 ').

10. shaft joint (1) according to claim 9, characterized in that the composite joint body (9, 9 ') ball tracks

(7) with a web base (12) and web sides (13, 13 '), which are designed as undercuts, recesses and / or profiles.

11. shaft joint (1) according to one or more of the preceding claims, characterized in that the joint bodies (9, 9 ') are axially compressible parts.

12. Shaft joint (1) according to claim 9, characterized in that two joint bodies (9, 9 '), preferably non-positively, materially and / or positively, are connected to one another on the contact surfaces (10, 10') and the inner joint and / or form the outer joint part (2, 3).

13. shaft joint (1) according to one or more of the preceding claims, characterized in that the edges of the contact surfaces (10, 10 ') at least partially abut each other on the respective track side (13, 13') of the ball tracks (7).

14. shaft joint (1) according to one or more of the preceding claims, characterized in that the edges of the contact surfaces (10, 10 ') at least partially abut each other in the respective track base (12) of the ball tracks (7).

15. shaft joint (1) according to one or more of the preceding claims, characterized in that the edges do not intersect the running surfaces (16, 16 ') of the balls (6).

16. shaft joint (1) according to one or more of the preceding claims, characterized in that the ball tracks (7) are polygonal or round, preferably elliptical.

17. shaft joint (1) according to one or more of the preceding claims, characterized in that at least three balls (6) each in a ball track (7) guide the inner joint part (3) in the outer joint part (2).

18. A shaft joint (1) according to one or more of the preceding claims, characterized in that the inner and / or outer joint part (2, 3) is arranged on the respective shaft (4, 5) and the joint body (9, 9 ') the corresponding shaft (5) are axially attached.