DE10260173A1 - CV Joint - Google Patents

Abstract

A ball constant velocity joint for a motor vehicle comprises an outer part which has raceways on its inside, an inner part (3) which is arranged in the outer part and has raceways (5) on its outside which are opposite the raceways of the outer part, each with a raceway ( 5) form a pair of raceways on the outer part and on the inner part (3), and balls which are accommodated in the raceway pairs, a ball (6) being supported at least on one ball raceway (4, 5) via at least one contact point. Along the course of the ball track (4, 5), the osculation of the ball track (4, 5) at the contact point or contact points becomes narrower or wider, i.e. H. the radius of curvature of the track profile cross section at the two contact points increases or decreases. By varying the osculation, the lifespan and breaking strength can be increased. Furthermore, the functionality is improved at large flexion angles of the joint. The ball constant velocity joint is also easy and inexpensive to manufacture.

Description

The invention relates to a Ball constant velocity joint comprising an outer part, which on its inside Has ball raceways, an inner part that in the outer part is arranged and on its outside Has ball raceways which are opposite the ball raceways of the outer part, each with a ball track on the outer part and on the inner part form a pair of tracks, and balls that are included in the pairs of tracks are, wherein a ball at least on a ball track via at least one contact point supported is.

Such constant velocity ball joints are used, for example, in drive shafts of motor vehicles and are generally known from the prior art.

For A perfect function of the joint is the power transmission between the raceways of the inner part and the raceways of the outer part via the Balls of special importance. For elliptical or Gothic Career paths exist between the career path and a ball each two contact points. Depending on the direction of torque or Direction of rotation only loaded one of the contact points, resulting in a significant mechanical stress on the raceways results.

The location and size of the contact points practice a noticeable influence on the breaking strength and life span of the constant velocity joint. in this connection particular attention must be paid to that at a Joint flexion unevenly affects the forces caused by the torque the balls are distributed. Consequently, with every revolution bending positions with larger and smaller Burden.

The invention contemplates a constant velocity ball joint to create the kind mentioned above, which is characterized by a high Excellent durability and breaking strength.

This task is accomplished through a constant velocity ball joint solved with the features of claim 1, the variable osculation the ball raceways on the balls.

According to the invention is along the osculation of the ball track in the course of a ball track closer or farther at the contact point (s), d. H. the radius of curvature of the career profile cross section at the two contact points from or to.

Through a targeted change or variation of the osculation at the higher stressed positions can be the size and location of the contact points and thereby affect the service life and breaking strength increase. So can the course of the career, the optimal printing area or blackmail in the career can be set. This means compared to the careers known today a significant improvement with a constant cross-sectional contour.

It can be a variable osculation alone on the outer part, only on the inner part or also on the inner part and on the outer part be provided. Possible is furthermore, only part of the raceways of the outer part or the inner part with a variable osculation.

According to an advantageous embodiment the osculation along the course of the ball track continuously tighter or wider. This is advantageous in terms of production technology.

However, in a further advantageous embodiment - regardless of a continuously narrowing or widening of the osculation - at contact points with larger operating loads larger radius of curvature than provided at contact points with lower operating loads.

The radius of curvature is preferred of the track profile cross section one of the wrap φ of the respective Ball depending on the respective career. This enables over the variation osculation reduces stress in critical areas with little wrap. With a smaller wrap φ, for example a larger radius of curvature to get voted.

After another advantageous one Design is the radius of curvature of the career profile cross section the course of the ball track on the outer part from the insertion side of the inner part to the opposite Page larger, d. h the osculation decreases or continues.

For the production of the raceways, for example elliptical or can be gothic, can be conventional Use manufacturing processes. For example, it is possible to run the tracks with variable osculation through a machining process manufacture. Above all, common milling and / or grinding processes come into question. Farther Is it possible, Pre-forged ball raceways with varying osculation.

Of course, a variable osculation however, also in the case of raceways in the shape of an arc be provided.

In principle, for a ball, the above two contact points are supported against a raceway, the contact angle α to the central axis the career over the course of the career remains constant.

However, it is also possible to and function optimization the variable osculation with a variation of the contact angle α combine. So in addition the contact angle α one Ball can be varied along the ball track, preferably this a function dependent on the ball wrap φ is.

It has been shown that the Contact angle α has a significant influence on the life and breaking strength of the joint. The design of the contact angle α, which is dependent on the wrap, allows the mechanical load in the respective region of the track to be further optimized, so that the pressure resistance is increased and the service life is extended. In addition, the distribution of forces in the joint is advantageously influenced.

The invention further enables the combination of forged and machined raceways or Joint components in one joint.

The contact angles α on the inside and outer part are convenient coordinated.

The invention is explained below of an embodiment shown in the drawing. The Drawing shows in:

1 2 shows a spatial representation of an exemplary embodiment of a ball constant velocity joint with variable osculation according to the invention,

2 a spatial representation of the outer part of the ball constant velocity joint with a view of some of the ball raceways,

3 a cross-sectional view of the career profile along the line III-III in 2 .

4 a cross-sectional view of the career profile along the line IV-IV in 2 .

5 a cross-sectional view of the career profile along the line VV in 2 .

6 1 shows a diagram to illustrate the osculation value r _k / r as a function of the wrapping φ of the ball,

7 a diagram illustrating a varying contact angle curve along a track for a modification of the ball constant velocity joint according to the 1 to 6 , and in

8th a diagram illustrating the contact angle α as a function of the wrap φ of the ball for the modification of the ball constant velocity joint with a varying contact angle.

This in 1 Ball constant velocity joint shown as an example 1 includes an outer part 2 and an inner part 3 , Both the outer part 2 as well as the inner part 3 are on their mutually facing, radial sides with raceways 4 respectively. 5 provided, each in pairs a ball 6 take up. The inner part 3 , this is a recording 7 for a shaft, opposite the outer part 2 be pivoted. The outer part 2 according to the embodiment has a bell-like, the inner part 3 enclosing shape and has a wave approach 8th on.

There is also a cage 9 between the outer part 2 and the inner part 3 provided the window for receiving the balls 6 and possibly also for guiding the same.

How 1 shows, each form a career 4 respectively. 5 on the inside of the outer part 2 and on the outside of the inner part 3 a pair of careers. The raceways are designed such that the associated balls 6 via two contact points P ₁ and P ₂ against the respective career 4 respectively. 5 are supported. This is particularly the case with elliptical and Gothic careers.

The careers 4 respectively. 5 are designed with variable osculation. This means that the osculation of the ball raceways along the course of the ball raceways 4 respectively. 5 to the respective ball 6 becomes narrower or wider at the two contact points P ₁ and P ₂ . In the 3 to 5 , the career profile cross sections of a selected career 4 on the outer part 2 at various points along the career 4 show, this can be seen from the radii of curvature r _a , r _b and r _c . A smaller radius of curvature means a closer osculation, a larger radius of curvature, on the other hand, a further osculation at the contact points P ₁ and P ₂ . Since the radii of curvature r _a , r _b and r _{c are} larger than the sphere radius r _k , the respective center of curvature M _a , M _b and M _c lies outside the sphere center M _k .

From the order of the 3 to 5 it can be seen that the osculation along the course of the ball track 4 continuously narrowing in one direction. However, this is not mandatory. Rather, the course of the radius of curvature along the ball track 4 chosen such that a larger radius of curvature is provided at the contact points with larger operating loads than at contact points with lower operating loads. In most cases, however, the places of greatest stress will be in the area of large diffraction angles, ie at the end of the track.

In the embodiment shown here, the smallest radius of curvature r _{c is} for the raceways 4 of the outer part 2 on the insertion side of the inner part 3 , From there, the radius increases continuously to the opposite end of the track, so that r _a > r _b > r _c > r _k . On the side of the greatest load, this results in a comparatively wide osculation, which means that the contact points that arise in this area with the tension area that extends beyond the actual contact surface can still be absorbed by the raceway even with a lower wrap φ there. The edge of the track remains undamaged.

The radius of curvature r _a , r _b , r _{c of} the track profile cross section is here one of the wrap φ of the respective ball 6 dependent function is. 6 shows, by way of example, the course of the osculation value r / r _k , ie the ratio of raceway radius r to ball radius r _k as a function of the wrap φ. With a smaller loop φ _{0 there} is a larger raceway radius of curvature r _a , r _b , r _c , but with a larger wrap φ _{max there} is a smaller raceway radius of curvature r _a , r _b , r _c .

A variable osculation in a corresponding manner is also on the raceways 5 of the inner part 3 intended.

However, it is also possible to use only the raceways 4 of the outer part 2 or the careers 5 of the inner part 3 to be equipped with a variable osculation.

In the embodiment shown here, all contact points P ₁ or P _{2 have} a career 4 respectively. 5 the contact angle α over the course of the career 4 respectively. 5 constant.

The contact angle α is understood here to mean the angle between the central axis A of the track profile cross section to the respective contact point P ₁ or P ₂ .

In a modification of the exemplary embodiment explained above, the contact angle α changes along the track 4 respectively. 5 , To optimize the mechanical stress on the constant velocity joint 1 The contact angle α is determined as a mathematical function α = f (φ) of the wrapping φ of the respective ball 6 through the respective career 4 respectively. 5 , because the wrap or wrap angle φ is along the track 4 respectively. 5 changed. The variation of the contact angle α can also be used to distribute the forces in the joint 1 to influence.

8th shows the dependence of the contact angle α on the wrap angle φ by way of example as a linearly increasing function α = c ₁ ? φ + c ₂ . However, other functional profiles with increasing characteristics are also conceivable here.

On the outer part 2 the one in the 1 to 5 The basic shape shown can be, for example, in the direction of the longitudinal extension of the track 4 respectively. 5 , ie depending on the longitudinal extension parameter x of the in 7 based on the solid line 11 shown course of the contact angle α are provided when the wrap φ is greatest in the central region of the raceway.

However, it is also possible to Contact angle course on the radius of curvature of the career cross-section. For example, with smaller ones Radii r a smaller contact angle α can be chosen to be at a strong Joint flexion to avoid deformation on the raceway edge. It then α = f (φ, r).

The careers 4 respectively. 5 can be manufactured using conventional manufacturing processes. Milling and grinding processes are particularly suitable. It is also possible to either on the outer part 2 or on the inner part 3 use forged raceways and combine them with a counterpart whose raceways are machined.

This results in a constant velocity ball joint that on the one hand has a long service life and high breaking strength, on the other hand, it can be produced simply and inexpensively.

Due to the variable osculation over the The pressure ellipse can be applied to the entire course of the ball raceways Contact points can be optimally adapted to the respective load.

In addition, the shape according to the invention the careers achieved a functional improvement. In particular there is a risk of jamming at strong flexion angles under high load of the joint is reduced.

However, the invention is not based on that explained embodiment and the described modifications are limited, but rather include all in the claims specified constant velocity ball joints.

1

CV Joint

2

outer part

3

inner part

4

career of the outer part

5

career of the inner part

6

Bullet

7

shaft mount

8th

shaft extension

9

Cage

11

Contact angle function dependent on of the longitudinal extension parameter x

12

Contact angle function dependent on the wrap

α

contact angle

φ

wrap or wrap angle

A

central axis of the career profile cross section

M _i

Focus

P ₁

contact point

P ₂

contact point

r _a

radius of curvature

r _b

radius of curvature

r _c

radius of curvature

r _k

spherical radius

Claims (12)

Ball constant velocity joint, in particular for installation in a motor vehicle, comprising: an outer part ( 2 ), which has ball raceways on the inside ( 4 ), - an inner part ( 3 ) that in the outer part ( 2 ) is arranged and on its outside ball raceways ( 5 ), which the ball raceways ( 4 ) of the outer part ( 2 ) face each other, each with a ball raceway ( 4 . 5 ) on the outer part ( 2 ) and on the inner part ( 3 ) form a pair of careers, and - balls ( 6 ), which are included in the pairs of tracks, one ball ( 6 ) at least on a ball track ( 4 . 5 ) is supported via at least one contact point (P1, P2), characterized in that that along the course of the ball track ( 4 . 5 ) the osculation of the ball track ( 4 . 5 ) at the contact point (s) (P ₁ , P ₂ ) becomes narrower or wider, ie the radius of curvature (r _a , r _b , r _c ) of the track profile cross section at the two contact points (P ₁ , P ₂ ) increases or decreases. Ball constant velocity joint according to claim 1, characterized in that the osculation along the course of the ball raceway ( 4 . 5 ) is getting narrower or wider. Ball constant velocity joint according to claim 1 or 2, characterized in that a larger radius of curvature (r _a , r _b , r _c ) is provided at contact points (P ₁ , P ₂ ) with larger operating loads than at contact points (P ₁ , P ₂ ) with lower operating loads is. Ball constant velocity joint according to one of claims 1 to 3, characterized in that the radius of curvature (r _a , r _b , r _c ) of the track profile cross section is one of the wrap φ of the respective ball ( 6 ) through the respective career ( 4 . 5 ) is a dependent function, in particular in such a way that with a smaller wrap φ there is a larger radius of curvature ((r _a , r _b , r _c ). Ball constant velocity joint according to one of claims 1 to 4, characterized in that the radius of curvature (r _a , r _b , r _c ) of the track profile cross section over the course of the ball track ( 5 ) on the outer part ( 2 ) from the insertion side of the inner part ( 3 ) increases on the opposite side, ie the osculation decreases. Ball constant velocity joint according to one of claims 1 to 5, characterized in that the ball raceway ( 4 . 5 ) is an elliptical or Gothic career. Ball constant velocity joint according to one of claims 1 to 5, characterized in that the ball raceway ( 4 . 5 ) is an arc-shaped track. Ball constant velocity joint according to one of claims 1 to 7, characterized in that the ball raceway ( 4 . 5 ) with variable osculation made by a machining process, in particular milled and / or ground. Ball constant velocity joint according to one of claims 1 to 8, characterized in that the ball raceway ( 4 . 5 ) is forged with variable osculation. Ball constant velocity joint according to one of claims 1 to 9, characterized in that for a ball raceway (via ₁ contact points (P ₁ , P ₂ )) ( 4 . 5 ) supported ball ( 6 ) the contact angle a to the central axis (A) of the track over the course of the ball track ( 4 . 5 ) is constant. Ball constant velocity joint according to one of claims 1 to 9, characterized in that for a ball raceway (via ₁ contact points (P ₁ , P ₂ )) ( 4 . 5 ) supported ball ( 6 ) the contact angle α along the ball track ( 4 . 5 ) varies and one of the wrapping φ of the respective ball ( 6 ) through the respective career ( 4 . 5 ) dependent function. Ball constant velocity joint according to claim 11, characterized characterized in that the Contact angle α with decreasing Wrap φ smaller becomes.