WO2012028459A1

WO2012028459A1 - Spur toothing, optimized for engagement, of a wheel hub rotary joint arrangement

Info

Publication number: WO2012028459A1
Application number: PCT/EP2011/064168
Authority: WO
Inventors: Peter Niebling; Roland Langer
Original assignee: Schaeffler Technologies Gmbh & Co. Kg
Priority date: 2010-09-03
Filing date: 2011-08-17
Publication date: 2012-03-08
Also published as: DE102010036254A1

Abstract

The invention relates, in summary, to a wheel hub rotary joint arrangement in which the wheel hub has a spur toothing and the rotary joint has a connecting element with a counterpart spur toothing, and the two toothings are formed in each case by the teeth and tooth spaces which extend in the radial direction and which alternate in the circumferential direction. Proposed is a wheel hub rotary joint arrangement which, while maintaining the known characteristics of such arrangements, avoids the disadvantageous disks of a spur toothing and of a counterpart toothing, such that a greater maximum torque can be transmitted to the wheel hub. This is achieved in that the teeth of the spur toothing have in each case an engagement edge which forms a first straight line, and tooth spaces which correspond to the teeth in engagement form a second straight line, wherein the two straight lines run parallel to one another up to a tolerance of +1° to -1°.

Description

Name of the invention

Interference-optimized face gear of a hub-pivot assembly

description

Field of the invention

Wheel hub pivot assembly in which the wheel hub has a front toothing and the rotary joint has a connecting element with a Gegenstirnverzah- tion and both teeth are each formed by the extending in the radial direction and circumferentially alternating teeth and tooth valleys. State of the art

Background of the invention

Spur-toothed wheel bearing units are used, for example, in passenger cars. In contrast to radially toothed wheel bearing units end-toothed wheel bearing units are easier to manufacture, since lower requirements are placed on the accuracy of fit of the gears and also a space savings occurs. In the case of an end-toothed wheel bearing unit, just as in the case of a spur-toothed wheel bearing unit, the torque transmission also depends on the form-fit of the toothings or their engagement with one another. The engagement can be increased in the front-toothed unit on the one hand by the corresponding torque of the fastening screw, but also by the formation of the Gearing. For example, a larger tooth depth leads to a greater positive locking and thus to a better torque transmission. From DE10 2005 054 283 B4 a wheel hub rotary joint arrangement is known, which has an end toothing with a counter toothing, wherein a radially outer lying part of the engaging teeth on the engagement of the teeth ahead in the axial direction, that is, with an axial screwing of the two teeth These first touch radially outside and the teeth fully engage only after the tightening of the fastening screw completely.

This is disadvantageous in that a tension within the wheel bearing of different components is unnecessarily unevenly loaded and thus risking possible breakage, which reduces the service life of the wheel hub pivot assembly.

Task summary of the invention

The object of the invention is therefore to provide a cost-effective, front-toothed wheel hub joint arrangement which has the largest possible Tragan- part and a high rigidity, with an optimum pressure and stress distribution in the toothing is achieved.

The object is achieved by a wheel hub pivot assembly of the type mentioned above in that the teeth of the spur gear each have a first straight forming engagement edge and to the teeth in engagement corresponding tooth valleys form a second straight line, both straight lines to a tolerance of + 1 ° to -1 ° parallel to each other run.

The engaging flanks and tooth valleys are exactly or substantially radial to the axis of rotation of the wheel hub pivot assembly. A straight line of an engagement edge or a tooth valley is formed by the tangent at the respective engagement edge or the respective tooth valley, wherein the tangent is arranged at the point of least curvature of the engagement edge of the tooth or the tooth valley. The engagement edge is the axially outermost edge of the tooth. It is quite conceivable that the tooth has several edges at the axial end. Thus, the edge that is located most axially outboard is the engagement edge. It is also conceivable that several mesh edges exist. These then span an axial engagement surface and are all equally axially outboard. Alternatively, an engagement edge may also be rounded or flattened. The same applies to the dental valleys, which can be defined by one or more notches. The tooth valley is defined by the notch or notches most axially disposed toward the interior of the component, wherein the toothing forming member may be a wheel hub or a connecting member of the rotary joint.

According to the invention, the parallelism of the first and second straight lines is determined. In the screw connection, both parallel straight lines are approximated to each other and lie directly after each other after the screwing, whereby it can be assumed approximately that both straight lines are in one another, in other words, collinear.

In an advantageous embodiment, the first and second gears intersect the axis of rotation of the wheel hub pivot assembly. Thus, the surface tooth flank is well aligned to achieve a positive fit and allows easy production of the ring gear by a Kaltumfor- mung, eg with a rolling rivet head.

In an advantageous embodiment, the first and second straight line form an angle α with the axis of rotation, wherein the angle α is 75 °, 80 °, 85 ° or 90 ° or has a value between these values. In this way, the shape of the teeth is adaptable, which can then be formed not only from the axial direction but also in the radial direction. Thus, with a certain overhead, the positive connection and thus to improve the maximum transferable torque.

Advantageously, the teeth of the counter-end teeth each have a first straight forming engagement edge and the tooth teeth of the spur teeth corresponding to the teeth form a second straight line, both straight lines, to a tolerance of +1 ° to -1 ° parallel to each other run.

In an advantageous embodiment, the tooth base planes of the two teeth are arranged at an angle of 0 ° to a tolerance of + 0.5 ° to -0.5 ° to each other.

Dental basal planes are virtual planes that are located between the valleys and engagement edges of the spur or counter teeth. They are arranged between the first plane or first cone-like surface, which is spanned by the engagement edges, and the second plane or second cone-like surface, which is spanned by the valleys of the same toothing. If the valleys and engagement edges form planes, the tooth base plane occupies the same distance to these two planes and is arranged plane-parallel to them. If the first straight lines and / or the second straight lines each form a first and a second cone-like surface, or a first plane and a second cone-like surface or a first cone-like surface and a second plane, the tooth base plane is spanned by the points that belong to the respective area or level have the same axial distance. The tooth base plane is used to characterize a toothing (spur toothing or counter toothing). Ideally, the tooth base planes of the two toothings are at least plane-parallel or approximately coplanar with each other during the procedure. Parallelism of two levels in this context means that a normal of one level is also a normal of the other level. A special case occurs when the levels are formed by the same points. In this case they are coplanar.

If the tooth base planes of an end toothing and a counter toothing are approximately coplanar with each other, they enclose the angle of 0 degrees with respect to each other. In this case, the least possible damaging stress that does not contribute to the increase of the maximum torque is present within the arrangement to avoid the Tellereffekts. Tests have confirmed that a larger tolerance leads to disadvantageous distortions within the teeth. Advantageously, the first straight line of the counter-toothing and the second straight line of the spur toothing intersect with the axis of rotation of the wheel hub / swivel assembly at one point.

Advantageously, the first and the second straight line includes a second angle β with the axis of rotation and the second angle is 75 °, 80 °, 85 ° or 90 ° or has a value lying between these values. It is particularly advantageous if α and β are the same size, or differ only insignificantly. Further advantageous embodiments and preferred developments of the invention can be taken from the description of the figures and / or the dependent claims. In the following the invention will be described and explained in more detail with reference to the embodiments illustrated in the figures.

a double-row wheel bearing in longitudinal section along the axis of rotation, an end teeth with a counter teeth in engagement, the spur gear teeth with the counter teeth of Figure 2, axially spaced, a spur gear teeth with an axially spaced counter teeth, the spur gear teeth and the counter teeth of the wheel hub pivot assembly of FIG. 1 in engagement, a first toothing with engagement surface, and a second toothing with partially anticipatory engagement surface according to the prior art.

Exemplary embodiment of the drawings

1 shows a double-row wheel bearing in longitudinal section along the rotatable onsachse R. The double-row wheel bearing has an outer ring 26, which includes the two rows of rolling elements 27 radially and in which the wheel hub 30 is mounted on the two rows of rolling elements 27. The double row wheel bearing is shown in a wheel hub pivot assembly that is engageable with two different pairs of gears in engagement 18. Here, the spur gear teeth 1 1 and the counter teeth 12 form a pair of teeth, and the spur gear teeth 13 with the counter teeth 14th

The spur gears 1 1, 13 are formed on Wälznietbund of the wheel bearing and are clamped by means of the fastening screw 25 against the counter teeth 12,14, or are in engagement with each other. The spur gearing 1 1, 13 are formed on Wälznietbund the wheel hub 30, which is also integrally connected to the wheel flange.

Furthermore, the counter teeth and 12,14 were formed with the joint bell 31, wherein the joint bell 31 is a connecting element of the unillustrated rotary joint.

Fig. 2 shows the spur gear teeth 1 1 with the counter teeth 12 in engagement. All tooth edges of the spur gear teeth 1 1 lie on the plane K1, which is arranged perpendicular to the axis of rotation R. Furthermore, in the plane K1, the tooth valleys of the counter-toothing 12 are also approximately assumed, so that the corresponding tooth edges and tooth valleys axially approach each other during engagement in such a way that they approximately span the plane K1. The same applies to the plane K2, which is formed by the valleys of the spur gear teeth 1 1, as well as by the tooth edges of the counter teeth 12.

Parallel to the plane K1 and the plane K2 the tooth base plane ZE1 of the spur gear teeth 1 1 is arranged. The numeric basis level ZE1 is coplanar. nar to the tooth base plane ZE3, which is associated with the counter teeth 12. The respective tooth base plane ZE1, ZE3 is formed according to the described manner from the tooth valleys and engagement edges of the teeth of the respective teeth 1 1, 12.

Fig. 3 shows the spur gear teeth 1 1 with the counter teeth 12 of Figure 2, axially spaced. The engagement edge 28 of the tooth 17 of the spur gear teeth 1 1 is still parallel to the tooth valley 15 of the counter teeth 12, but not approximately collinear, as shown in the engagement in Fig. 2. Now the tooth base planes ZE1, ZE3 no longer coincide, but are arranged plane-parallel to one another, as is the case, for example, in an assembly step preceding the procedure.

The engagement edge 28 of the tooth 17 forms a straight line G1, which is arranged at right angles to the axis of rotation R. Furthermore, the straight line G1 is arranged parallel to the second straight line G2, which is formed by the corresponding tooth valley 15 of the counter-toothing 12. For this straight line formation, the largest, almost uncurved section of the engagement edge 28, or the almost non-curved section of the tooth valley 15, is used in order to form the respective straight line G1, G2 in the extension thereof.

It should be noted that the teeth as shown in Figs. 2 and 3 are rarely used in practice because they are very difficult to form by a conventional forming method. The problem is at this point in particular the formation of the radially inner part of the teeth. However, it is not always necessary that the teeth must form the respective straight line with the entire tooth edge. The tooth edge may well fall axially in the radial inner direction and deviate from the straight line.

In engagement, the straight lines G1 and G2, as shown in Fig. 2, coincide in the plane K1. Fig. 4 shows a spur gear teeth 13 with an axially spaced counter teeth 14. The first straight line G1, which is formed by the engagement edge 29 of the tooth 22, forms with the axis of rotation R an angle a, as well as the second straight line D2 through the corresponding tooth valley of the counter-toothing 14 is formed. The same applies to the first straight line G1 'and the second straight line G2'. Both are parallel to each other and form an angle a with the axis of rotation R. When making the procedure thus the tooth 22 comes into contact with the opposite tooth valley of the counter teeth 14 almost simultaneously.

The first and second straight lines H2, H2 'form, with the axis of rotation R, the angle β, which is optionally the same as a, that is to say α = β. Thus, the teeth 19,22 have a nearly triangular shape in longitudinal section. However, this is not necessarily the case. The angle β can still assume any conceivable value, such as 90 °, 85 °, 80 ° or 75 ° or any value within the specified values. In this way, the tooth shape can be adapted to the respective application and can optionally be designed not only by cold forming in the axial direction, but also by cold forming from radial directions, using, for example, different rivet head setters or different rolling methods. Alternatively, a cutting treatment for increasing the tooth depth is conceivable, that is, a further depression of the tooth valleys of the respective teeth is also possible later.

In all embodiments of the description of the figures, the parallelism of the first straight line G1, G1 'to the corresponding second straight line G2, G2' ideally deviates maximally by ± 0.5 °. In this way it is ensured that no adverse internal tension occurs. The deviations from the ideal shape are small enough so that the occurring deformations remain localized at the point of origin and no component forms a damaging tension pattern. Fig. 5 shows in cross-section to the axis of rotation R spur gear teeth and an engaging counter teeth as also in the wheel hub pivot assembly of Figure 1 can be implemented. The two tooth base planes ZE2, ZE4 of the participating gears enclose an angle of 0 ° with one another, or are coplanar with one another. The larger the tooth length ZL, the greater the positive locking, but the more difficult it is to maintain the desired tolerance over the entire tooth length ZL. Fig. 6 shows a first toothing with engagement surface 43. The engagement surface 43 is bounded in the circumferential direction by two engagement edges 40,41. Both engagement edges 41, 42 are in the axial direction furthest outward. Contact surface 43 indicates that there is a large area during engagement and even before the tension. This is possible if the corresponding tooth valley (not shown) of the counter toothing has two radially extending valleys, which ideally also span one surface.

FIG. 7 shows a second toothing with leading engagement surface according to the prior art. The contact point 53 on the engagement surface indicates at which point when screwing first a contact with the counter toothing occurs. Full engagement, that is, a contact that also occurs radially on the inner surface, may be present only after screwing and arise under harmful tension. This can now be avoided with the teaching according to the invention.

In summary, the invention relates to a wheel hub rotary joint arrangement in which the wheel hub has a front toothing and the rotary joint has a connecting element with a counter-end toothing and both toothings are each formed by the teeth and dental valleys extending in the radial direction and alternating in the circumferential direction. It is proposed a wheel hub-pivot assembly gen, which prevents the disadvantageous disposition of a spur gear teeth or a counter-toothing while maintaining the known properties of such arrangements and thus a greater maximum torque is transferable to the wheel hub. This is achieved in that the teeth of the spur gear each have a first straight line forming engagement edge and to the teeth in engagement corresponding tooth valleys form a second straight line, both straight lines parallel to each other to a tolerance of +1 ° to -1 °

LIST OF REFERENCE NUMBERS

1 1 spur toothing 12 counter toothing

13 spur gear teeth 14 counter teeth

15 tooth valley 16 tooth

17 tooth 18 engagement of the teeth

19 tooth 20 tooth valley

21 tooth valley 22 tooth

25 fixing screw 26 outer ring

27 Rolling elements 28 engaging edge

29 engaging edge 30 wheel hub

31 joint bell 40 engaging edge

41 engagement edge 42 engagement surface

43 Contact surface 53 Contact point α Straight line ß Straight line angle

G1 first angle G1 'first angle

G2 second angle G2 'second angle

H2 second angle H2 'second angle

K1 level K2 level

ZE1 tooth base plane ZE2 tooth base plane

ZE3 tooth base plane ZE4 tooth base plane

R rotation axis

Claims

claims

1 . Wheel hub pivot assembly, wherein the wheel hub (30) has a spur gear teeth (1 1, 13) and the pivot joint, a connecting element (31) with a counter-end teeth (12,14) and both teeth (11, 12, 13, 14) respectively of the formed in the radial direction and alternating in the circumferential direction teeth (16, 17, 19, 22) and tooth valleys (15,20) are formed, characterized in that the teeth (17,22) of the front teeth (1 1 , 13) each have a first straight line (G1, G1 ') forming engagement edge (28,29) and to the teeth (17,22) in engagement corresponding tooth valleys (15,20) of the counter-end teeth (12,14) has a second straight line (G2, G2 ') form, wherein both straight lines (G1, G1', G2, G2 ') parallel to each other to a tolerance of +1 ° to -1 °.

A wheel hub pivot assembly according to claim 1, wherein the first (G1, G1 ') and second straight lines (G2, G2') intersect the rotational axis (R) of the wheel hub pivot assembly.

3. A rotary hub pivot assembly according to claim 2, wherein the first (G1, G1 ') and second straight line (G2, G2') include a first angle (a) with the axis of rotation (R) and the first angle (a) 75 °, 80 °, 85 °, 90 ° or the first angle (a) has a value lying between these values.

4. Hub-swivel assembly according to one of the preceding claims, wherein the teeth (16,19) of the counter-end teeth (12,14) each having a first straight forming engagement edge and to the teeth (16,19) in engagement corresponding tooth valleys (21) form a second straight line (H2, H2 ¹ ), with both straight lines (H2, H2 ') extending parallel to one another, up to a tolerance of +1 ° to -1 °.

5. hub-pivot assembly according to claim 4, wherein the tooth base planes (ZE1, ZE2) of the two gears (11, 12, 13, 14) at an angle of 0 ° to a tolerance of + 0.5 ° to -0.5 ° are arranged to each other.

A wheel hub pivot assembly according to claim 4 or 5, wherein in the first and second straight lines (H2, H2 ') intersect the axis of rotation (R) of the wheel hub pivot assembly.

7. hub-pivot assembly according to claim 4,5 or 6, wherein the first and second straight line (H2, H2 ') include a second angle (ß) with the axis of rotation (R) and the second angle (ß) 75 °, 80 ° , 85 °, 90 ° or has a value between these values.