DE102007048327A1 - Universal joint has cage control angle greater than control angle of ball tracks, with control angle of ball tracks of joint outer and inner sections less than 7 degrees, and with cage control angle within range of 4 to 15 degrees - Google Patents

Abstract

The universal joint, with a cage (4) guided between guiding surfaces (7,8) of the joint's inner (3) and outer (2) sections, and balls (6) installed in openings (5) in the cage, has the cage control angle greater than the control angle of the ball tracks. The control angle of a ball track (9) of the joint outer section is less than 7 degrees, as is the control angle of a ball track (10) of the joint inner section. The cage control angle lies within the range of 4 to 15 degrees.

Description

The The invention relates to a constant velocity fixed joint comprising Joint outer part, which has on its inner circumference a cage guide surface and a plurality of ball raceways, an inner joint part, the on its outer circumference a cage guide surface and a plurality of ball races, one between arranged the outer joint part and the inner joint part Cage, between the cage guide surfaces the outer joint part and the inner joint part out is, and a variety of bullets, which are arranged in windows of the cage and are held by this in a joint median plane and with the ball raceways of the outer joint part and the inner joint part engage for torque transmission, wherein the Centers of curvature of the cage guide between the cage and the outer joint part and the Cage and the inner joint part to a Gelenkbeugezentrum are each offset axially, and the centers of curvature the ball raceways of the outer joint part and the inner joint part are each offset axially to the joint bending center.

such Joints allow angular compensation during transmission of torques. To ensure the function of the joint need the balls in a flexion of the joint, that is at a bending of the longitudinal axes of the outer joint part and the inner joint part to each other in the so-called homokinetic Plane or half-angle plane of the joint are controlled. The half-angle plane is perpendicular to the flexion axis of the joint, which bisects the angle between the longitudinal axes of the outer joint part and the inner joint part and through its intersection, the so-called flexion center of the joint, runs.

A first control system is based on an opposite axial offset of the centers of curvature of the ball raceways of the outer joint part and the inner joint part of the joint bending center. This principle is first in the U.S. Patent No. 1,975,758 described by Bernard Stuber in 1934. The use of this principle in conjunction with a guided between the outer joint part and the inner joint part cage is in the U.S. Patent No. 2,046,584 revealed by Alfred Rzeppa from 1936.

A second control system uses an axial offset of the centers of curvature of the spherical guide surfaces between the cage and the inner joint part and the cage and the outer joint part. This principle is also from the U.S. Patent No. 1,975,758 known by Bernard Stuber.

The invention is based on a 1 shown joint 1 which combines both control systems, but career control is predominant. Between an outer joint part 2 and an inner joint part 3 is a cage 4 arranged, a variety of windows 5 for receiving one ball each 6 formed. The outer joint part 2 has on its inner circumference a spherical cage guide surface 7 and a variety of groove-like ball raceways 9 on. In the same way are on the outer circumference of the inner joint part 3 a spherical cage guide surface 8th and a variety of groove-like ball raceways 10 intended. The cage 4 slides with a substantially spherical outer surface 11 in the cage guide surface 7 of the outer joint part 2 and having a substantially spherical inner surface 12 on the cage guide surface 8th of the inner joint part 3 , Due to the curvature of the cage guide surfaces 7 and 8th is the cage 4 between the inner joint part 2 and the outer joint part 3 secured axially, but can pivot about the flexion center Z of the joint. When bending the joint by an angle β, the outer joint part to move 2 and the inner joint part 3 each β / 2 symmetric to the homokinetic plane E of the balls 6 ,

For controlling the balls, the centers of curvature P _Ba and P _{Bi of} the ball race radii R _Ba and R _{Bi of} the outer joint part 2 and the inner joint part 3 , each at the center of the sphere in question 6 are offset by the same amount V _AXa and V _AXi axially to the joint _{bending center} Z. The associated control angles are identified by the reference symbols ψ _Ba and ψ _Bi . These are calculated as follows: ψ Ba = arcsin (v Axa / R Ba ) and ψ Bi = arcsin (v Axi / R Bi )

at Today's joint designs, these control angles are larger as 7 °.

The tax effect follows from in 1 indicated normal forces F _BA and F _Bi at the contact points of the ball 6 with the raceways 9 and 10 , Depending on the respective control angle ψ _Ba and ψ _Bi results from the normal forces a force F _K on the cage 4 which becomes larger with increasing control angles. The of the bullets 6 on the cage 4 In turn, applied forces F _K must be within the joint, namely at the spherical cage guide surfaces 7 and 8th be supported and cause friction.

The centers of curvature P _Ka and P _{Ki of} the cage guide surfaces 7 and 8th of the outer joint part and the inner joint part are usually arranged in the joint bending center Z. It is also over Lich, these centers of curvature P _Ka and P _Ki in opposite directions by a degree OFF _Ka or OFF _Ki to the joint bending center Z slightly axially offset. From this, a cage control angle can be defined with reference to the effective diameter PCD of the extended joint: ψ K = arcsin (2 · OFF K / PCD).

Of the Invention is based on the object, the joint efficiency improve.

This object is achieved by a joint according to claim 1. The joint according to the invention is characterized in particular by the fact that the cage control angle ψ _K = arcsin (OFF _K / PCD) is greater than the track _{control angles} ψ _Ba = arcsin (V _AXa / R _Ba ) and ψ _Bi = arcsin (V _AXi / R _Bi ) , In this case, OFF _{K is} the axial offset of the centers of curvature (P _Ka , P _Ki ) of the cage guide on the outer joint part (FIG. 2 ) and on the inner joint part ( 3 ), PCD the effective diameter of the joint with the joint extended, V _AXa the axial offset of the center of curvature (P _Ba ) of the ball track ( 9 ) of the outer joint part ( 2 ) R _{Ba is} the center of the ball-related raceway center radius of the ball raceway (FIG. 9 ) _AXi the axial offset of the center of curvature (P _Bi ) of the ball track ( 10 ) of the inner joint part ( 3 ) and R _{Bi is} the center of the ball-related raceway center radius of the ball raceway (FIG. 10 ).

hereby result in lower control forces on the cage, so that the friction between the balls and the cage as well continue between the cage and the cage guide surfaces is reduced. Nevertheless, the control of the balls in the Homokinetic plane of the joint via the cage control continues to guarantee which now the main share the controller takes over.

Next an improvement in efficiency leads the invention Solution continues to increase the joint life. In particular, the wear on the cage and reduced at the ball races.

Further, advantageous embodiments are in the claims specified.

by virtue of of significantly larger compared to the current state of the art Offsets of the cage guide may be the control angle the ball raceways are lowered to below 7 °, so that the control forces from the track control very low become.

The The advantages mentioned above usually arise even if the axial offset of the centers of curvature of the cage guide is greater than the axial offset of the centers of curvature of Ball raceways.

Preferably is the axial offset of the cage guide more than 1.5 times the axial offset of the centers of curvature the ball raceways.

about the cage guide realized steering angle are larger than realized via the ball raceways Control angle. While the former is preferably in the range of 4 to 15 ° lie, are the career control angle of the invention Joint preferred between 0 and 7 °.

According to one Another advantageous embodiment, an additional Reducing the control angle of the ball raceways can be achieved by that the centers of curvature of the ball raceways beyond the respective component center axis are arranged.

The The principle explained above is suitable for both Joints where all ball raceway pairs are on the same side of the ball Open joint, as well as for so-called antireflective joints, in which the ball raceway pairs, for example, alternately in opposite Open directions.

The Number of balls is preferably selected ≥ 4 and is not limited to the top in principle. In the Usually you will have six, seven, eight or nine ball race pairs Provide with a corresponding number of balls.

following the invention with reference to an embodiment shown in the drawing explained in more detail. The drawing shows in:

1 a sectional view of an improvement in constant velocity joint, and in

2 a sectional view of a constant velocity joint according to an embodiment of the invention.

2 shows a constant velocity fixed joint 1 For example, it can be installed in a propeller shaft of a motor vehicle to transmit drive power from a transmission to a vehicle front wheel. It allows flexing angles of up to about 52 degrees.

The joint 1 includes an outer joint part 2 and an inner joint part 3 between which a cage 4 is arranged. The cage 4 has a variety of windows 5 for receiving one ball each 6 on. On the inner circumference of the outer joint part 2 are a cage guide surface 7 and a variety of groove-like ball raceways 9 educated. In the same way are on the outer circumference of the inner joint part 3 a cage guide surface 8th and a variety of groove-like ball raceways 10 intended. The cage 4 slides with an outer surface 11 in the substantially spherical cage guide surface 7 of the outer joint part 2 and with an inner surface 12 at the substantially spherical cage guide surface 8th of the inner joint part 3 , About the cage 4 be the balls 6 , each with a ball track 9 respectively. 10 of the outer joint part 2 and the inner joint part 3 engage for the purpose of torque transmission, at a flexion of the joint 1 in the homokinetic plane E of the spheres 6 or the half-angle plane of the joint held.

The control of the balls 6 into the homokinetic plane or half-angle plane E takes place by an axial offset of the centers of curvature P _Ba and P _{Bi of} the ball raceways 9 and 10 and by an axial offset of the centers of curvature P _Ka and P _{Ki of} the cage guide.

to Improving the efficiency of the joint is shown in the Joint causes the majority of control by the cage guide, while the remaining portion of career control in the Compared to conventional career control systems clearly is reduced. These are the two mentioned control systems in the manner explained in more detail below coordinated.

As 2 shows, have the spherical cage guide surfaces 7 and 8th of the outer joint part 2 and the inner joint part 3 axially offset to the joint bending center Z offset centers of curvature P _Ka and P _Ki on. In the present case, spherical cage guide surfaces are understood to mean all surface shapes which, in combination with the cage, cause pivoting about the axially offset centers P _Ka and P _Ki . The corresponding axial offset is in 2 marked with OFF _Ka and OFF _Ki and, as here in terms of size, hereinafter referred to as OFFK. In conjunction with the associated radii of curvature R _Ka and R _Ki , the cage control angle on the outer joint part arise 2 with ψ _Ka = arcsin (OFF _Ka / R _Ka ) and at the inner joint part 3 with ψ _Ki = arcsin (OFF _Ki / R _Ki ). The cage control angles ψ _Ka and ψ _Ki are on the order of 4 ° to 15 °. Since R _Ki and R _Ka approximately correspond to the effective diameter PCD with the joint extended, the cage control angle ψ _K can be referred to the effective diameter PCD in a simplified manner as follows: ψ K = arcsin (2 · OFF K / PCD)

From the location of the centers of curvature P _Ba and P _{Bi of} the effective sections of the ball raceways 9 and 10 taking into account the respective axial offset V _AXa and V _AXi to the joint _{bending center} Z and the associated, respectively to the center of the ball 6 related raceway center radii R _Ba and R _{Bi of} the ball raceways 9 and 10 the raceway control angle on the outer joint part 2 with ψ _Ba = arcsin (V _AXa / R _Ba ) and at the inner joint part 3 with ψ _Bi = arcsin (V _AXi / R _Bi ).

It is at the outer joint part 2 and at the inner joint part 3 the cage control angle ψ _{K is} greater than the associated raceway control angle ψ _Ba or ψ _Bi or ψ _Ka greater than ψ _Ba and ψ _Ki greater than ψ _Bi .

The raceway control angles ψ _Ba and ψ _Bi are preferably between 0 ° and 7 °.

As 2 Accordingly, the axial offset OFF _Ka or OFF _{Ki of} the respective center of curvature P _Ka or P _{Ki of} the cage guide is correspondingly greater than the axial offset V _AXa or V _{AXi of} the corresponding center of curvature P _Ba or P _{Bi of} the ball raceways 9 respectively. 10 , Preferably, the axial offset is OFF _{Ka of} the center of curvature P _{Ka of} the cage guide on the outer joint part 2 at least 1.5 times the axial offset V _{AXa of} the center of curvature P _{Ba of} the ball track 9 of the outer joint part 2 is. Accordingly, the axial offset becomes OFF _{Ki of} the center of curvature P _{Ki of} the cage guide at the inner joint part 3 with at least 1.5 times also significantly greater than the axial offset V _{AXi of} the center of curvature P _{Bi of} the ball track 10 of the inner joint part 3 selected.

In the illustrated embodiment, the centers of curvature P _Ba and P _{Bi are} the ball raceways 9 respectively. 10 on the respective component center axis A and B of the inner joint part 2 or outer joint part 3 , In a modification of the illustrated embodiment, however, one or both centers of curvature P _Ba or P _{Bi can} also be arranged beyond the component central axis A or B, which tends to result in smaller track control angles ψ _a and ψ _i .

The track center radii R _Ba and R _{Bi of} the ball raceways 9 and 10 can be chosen so that R _{Bi is} greater than R _Ba . Preferably, the raceway center radius R _{Bi is} the ball track 10 at the inner joint part 3 approximately at the contact circle diameter of a sphere 6 greater than R _Ba .

By the above-explained vote of the career control and the cage control arise, as in 2 indicated by F _K ', significantly lower control forces within the joint. This leads to a lower load on the cage 4 and the surface pairings between the cage guide surface 7 of the outer joint part 2 and the outer surface 11 and between the cage guide surface 8th of the inner joint part 3 and the inner surface 12 of the cage 4 , Furthermore, there is less wear on the raceways 9 and 10 , The reduced friction results in a higher joint life as well as improved joint efficiency.

The principle explained above can be used for all ball joints with more than three balls, with variants with six or eight balls are preferred. All pairs of ball raceways can open to the same side of the joint. In a bell-shaped outer joint part, this is preferably done to the open side. However, an opening of the ball raceway pairs in the direction of the opposing joint bottom is also possible. Furthermore, it is possible to perform the joint as Gegenbahnkonstruktion, in which the production points of the ball raceways 9 and 10 preferably alternately right and left axially offset to the joint bending center Z.

The The invention has been described above with reference to a preferred embodiment explained in more detail. However, she is not on this Embodiment limited, but includes all embodiments defined by the claims.

1

Constant velocity joint

2

Outer race

3

Inner race

4

Cage

5

cage window

6

Bullet

7

spherical Cage guide surface on the outer joint part

8th

spherical Cage guide surface on the inner joint part

9

Ball track at the outer joint part

10

Ball track at the inner joint part

11

spherical Outer surface of the cage

12

spherical Inner surface of the cage

13

contact line Ball / ball track on the outer joint part

14

contact line Ball / ball track on the inner joint part

A

Component central axis of the outer joint part

B

Component central axis of the inner joint part

e

homokinetic level

OFF _K

axial Offset of the centers of curvature of the cage

OFF _Ka

axial offset of the center of curvature of the cage guide surface 7

OFF _Ki

axial offset of the center of curvature of the cage guide surface 8th

P _Ba

Center of curvature of the ball track 9 of the outer joint part

P _Bi

Center of curvature of the ball track 10 of the inner joint part

P _Ka

Center of curvature of the cage guide surface 7

P _Ki

Center of curvature of the cage guide surface 8th

PCD

Effective diameter with stretched joint

R _Ba

Radius of curvature of the ball track 9 based on the ball center

R _Bi

Radius of curvature of the ball track 10 based on the ball center

R _Ka

Radius of curvature of the cage guide surface 7

R _Ki

Radius of curvature of the cage guide surface 8th

V _AXa

axial Offset of the center of curvature of the ball track of the Outer race

V _AXi

axial Offset of the center of curvature of the ball track of the Inner race

Z

Joint articulation center

_Ba

Career control angle at the outer joint part

ψ _Bi

Career control angle at the inner joint part

ψ _K

Cage control angle

ψ _Ka

Cage control angle at the outer joint part

ψ _Ki

Cage control angle at the inner joint part

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• US 1975758 [0003, 0004]
• - US 2046584 [0003]

Claims (12)

Constant velocity fixed joint, comprising an outer joint part ( 2 ), which has on its inner circumference a cage guide surface ( 7 ) as well as a multiplicity of ball raceways ( 9 ), an inner joint part ( 3 ), which has on its outer periphery a cage guide surface ( 8th ) as well as a multiplicity of ball raceways ( 10 ), one between the outer joint part ( 2 ) and the inner joint part ( 3 ) arranged cage ( 4 ) located between the cage guide surfaces ( 7 . 8th ) of the outer joint part and the inner joint part is guided, and a plurality of balls ( 6 ) in windows ( 5 ) of the cage ( 6 ) are arranged and held by this in a joint center plane (E) and with the ball raceways ( 9 . 10 ) of the outer joint part ( 2 ) and the inner joint part ( 3 ) are engaged for transmitting torque, wherein the centers of curvature (P _Ka , P _Ki ) of the cage guide between the cage ( 4 ) and the outer joint part ( 2 ) as well as the cage ( 4 ) and the inner joint part ( 3 ) are each offset axially to a joint bending center (Z), and the centers of curvature (P _Ba , P _Bi ) of the ball raceways ( 9 . 10 ) of the outer joint part ( 2 ) and the inner joint part ( 3 ) are offset axially relative to the joint bending center (Z), characterized in that the cage control angle ψ _K = arcsin (OFF _K / PCD) is greater than the track _{control angles} ψ _Ba = arcsin (V _AXa / R _Ba ) and ψ _Bi = arcsin ( V _AXi / R _Bi ), where OFF _{K is} the axial offset of the centers of curvature (P _Ka , P _Ki ) of the cage guide on the outer joint part (FIG. 2 ) and on the inner joint part ( 3 ), PCD the effective diameter of the joint with the joint extended, V _AXa the axial offset of the center of curvature (P _Ba ) of the ball track ( 9 ) of the outer joint part ( 2 ) R _{Ba is} the center of the ball-related raceway center radius of the ball raceway (FIG. 9 ) V _AXi the axial displacement of the center of curvature (P _Bi ) of the ball track ( 10 ) of the inner joint part ( 3 ), and R _{Bi is} the center of the ball-related raceway center radius of the ball raceway (FIG. 10 ). A constant velocity joint according to claim 1, characterized in that the running angle angle ψ _{Ba of} a ball track ( 9 ) of the outer joint part ( 2 ) is less than 7 °. A constant velocity joint according to claim 1 or 2, characterized in that the track control angle ψ _Bi a ball track ( 10 ) of the inner joint part ( 3 ) is less than 7 °. A constant velocity joint according to any one of claims 1 to 3, characterized in that the cage control angle ψ _{K is} in the range of 4 to 15 °. Constant velocity joint according to one of claims 1 to 4 or according to the preamble of patent claim 1, characterized in that the axial offset (OFF _K ) of the centers of curvature (P _Ka , P _Ki ) of the cage guide is greater than the axial offset (V _AXa , V _AXi ) of the centers of curvature (P _Ba , P _Bi ) of the ball raceways ( 9 . 10 ). Constant velocity joint according to one of claims 1 to 6, characterized in that the axial offset (OFF _K ) of the center of curvature (P _Ka ) of the cage guide on the outer joint part ( 2 ) At least 1.5 times the axial offset (V _AXa ) of the center of curvature (P _Ba ) of the ball track ( 9 ) of the outer joint part ( 2 ) is. Constant velocity joint according to one of claims 1 to 6, characterized in that the axial offset (OFF _K ) of the center of curvature (P _Ki ) of the cage guide on the inner joint part ( 3 ) at least 1.5 times the axial offset (V _AXi ) of the center of curvature (P _Bi ) of the ball track ( 10 ) of the inner joint part ( 3 ) is. A constant velocity joint according to any one of claims 1 to 7, characterized in that the center of curvature (P _Ba ) of the ball track ( 9 ) of the outer joint part ( 2 ) beyond the component central axis (A) of the outer joint part ( 2 ) is arranged. Constant velocity joint according to one of claims 1 to 8, characterized in that the center of curvature (P _Bi ) of the ball track ( 10 ) of the inner joint part ( 3 ) beyond the component central axis (B) of the inner joint part ( 3 ) is arranged. Constant velocity joint according to one of claims 1 to 9, characterized in that the radius of curvature (R _Bi ) of the ball track ( 10 ) of the inner joint part ( 3 ) is greater than the radius of curvature (R _Bi ) of the ball track ( 9 ) of the outer joint part ( 2 ). Constant velocity joint according to one of claims 1 to 10, characterized in that all ball raceway pairs ( 9 . 10 ) open to the same side of the joint. Constant velocity joint according to one of claims 1 to 10, characterized in that the ball raceway pairs ( 9 . 10 ) open in opposite directions.