DE102006033995A1 - Hub cover for wheel bearing, comprises multiple secured areas, of rotary protection, distributed over periphery of hub cover, where secured areas are subdivided, in peripheral direction, into successive segments with radial extension - Google Patents

Abstract

The cover comprises multiple secured areas, of a rotary protection, distributed over the periphery of the hub cover. The secured areas are subdivided, in peripheral direction, into successive segments with non-uniform radial extension. The segments deviate from each other in two secured areas. The rotating mounting is out-arranged as bayonet connection on bayonet structures (12) distributed over the periphery of the hub cover. Independent claims are also included for the following: (1) a wheel hub for the vehicle wheel (2) a cap for rotating fastener over bayonet structures.

Description

The Invention relates first a cover for a wheel bearing, with one on a wheel hub of a vehicle wheel turnable cap.

The The invention further relates to a wheel hub for a vehicle wheel, with a Hub body for receiving a wheel bearing around the hub body arranged fastening means for the vehicle wheel, as well as a a central opening the wheel hub surrounding, axially outwardly projecting edge with formed there structures for the rotational attachment of a cap.

The Invention finally relates a cap for rotatable attachment via bayonet structures on one circumferential edge of a wheel hub, wherein component of each bayonet structure a on an annular Wall portion of the cap is arranged projection.

Hub covers serve to close the outer ends of vehicle wheel hubs by means of a cover cap to protect the wheel bearing arranged thereon on the axle as well as the central axle nut. The attachment on the edge of the hub takes place eg in the EP 0 027 201 B1 over a thread.

An advanced hub cover is from the DE 199 46 923 A1 known. The cap is attached by means of a bayonet connection to the edge of the wheel hub. On the one hand on this edge, and on the other hand on the cap, a seal of elastic material is supported. By achieved due to their elasticity axial pressure of the positive connection of the bayonet connection should be maintained. Further, the elastic seal prevents penetration of dirt and moisture into the interior of the hub cover.

The between the wheel hub and the cap largely exposed Seal is there external influences like Dirt, salt and the permanently damaging UV radiation exposed so that it in Over time, a reduction in the elasticity of the seal can come. Because this elasticity However, secure the bayonet mount against accidental release should, leads any impairment the seal at the same time to a deterioration of the long-term safe Seat of the cap. This is especially true for rough field use, in the wheel hub and thus the cap often extreme Bumps and Exposed to shocks is.

aim The invention is that it is also in long and under harsh driving conditions taking place practice to no unwanted loosening of the cap can come from the wheel hub.

to solution the task is a hub cover of the type mentioned by a majority over the extent of the hub cover distributed backup areas a Anti-rotation lock, whereby the securing areas in the circumferential direction in successive segments with non-uniform radial extent are subdivided, and the sequence of segments in at least two the backup areas differ from each other.

In Regarding the wheel hub is the solution the task characterized by a plurality distributed over the circumference of the edge Fuse areas of a rotation lock, wherein the fuse areas in the circumferential direction in successive segments with nonuniform radial extent are divided, and the sequence of segments deviate from one another in at least two of the security areas is.

In With respect to the cap, the solution of the problem is characterized that on the annular Wall section of the cap locking elements are arranged that arranged the locking elements on different angular positions than the projections are, and that the locking elements continue from the open edge extend the cap away, as the projections.

Together is these solutions a fuse of the cap on the hub in such a way that it even with long while Use and frequent strong punches or bumps up the wheel bearing to no automatic loosening of the cap can come from the wheel hub. Such a loosening is through the The circumference of the hub cover prevents distributed securing areas. These are divided circumferentially into successive segments, the segments in the fuse areas are not uniformly radial Have extension, and also the sequence of segments in at least two of the fuse areas are different from each other.

A component of the latching device may be a detent element which interacts radially with the respective securing region and projects radially beyond the diameter up to which the radially outermost segment of the securing region extends. In this way, a turning of the cap is only possible when overcoming a considerable resistance to form, this applies in the same way for the tightening as loosening. The induced by deformation increased rotational resistance occurs not only in a single rotational position, but also at least one further rotation angle of the cap. This leads to additional security against accidental loosening of the cap.

at the locking element is preferably an elongated Projection, which z. B. can be made by material deformation. At least one of the longitudinal edges of the locking element extends in the circumferential direction between 0 ° and 25 ° to the axis of rotation the wheel bearing bent. Such an inclination turns out to be Remove the cap, for example to carry out maintenance work on the wheel bearing, an advantage.

Around in the interaction between the locking element and the individual Segments broken security area a certain compliance can reach that part of the hub cover, where the locking elements are formed, be deformable. Thus, the locking elements z. B. inside on an annular Be formed wall portion of the cap, of a round is deformable into a slightly out-of-round shape.

For the swivel attachment the cap is particularly suitable a bayonet. component the bayonet structure is preferably on the cap inside formed projection, such as a by material deformation of the cap manufactured projection. Another component of every bayonet structure can be over at a radial covenant the area of the bayonet structure out of the wheel hub trained Be undercut, wherein the radial collar in the circumferential direction below Forming the radially nonuniformly extending segments of the Secured area extended is. As a result, a simplification of the hub is possible because The radial collar formed there both the function of the undercut for the Bayonet, as well as the function of the security area according to the invention takes over.

For this It is also advantageous if both the locking element and the projection are formed on the inside of the cap, and himself the locking element in the longitudinal direction extends further from the open edge of the cap away than the Head Start.

Of Further proposed is a seal between the inside the cap and the wheel hub. In this way, moisture, dust and dirt not in the interior of the wheel hub and thus in the area get the wheel bearing.

Prefers Furthermore, an embodiment in which the projections radially continue to extend inward than the locking elements.

embodiments The invention will be explained in the following description, wherein the drawings are referred to. Show:

1 in a perspective view of a vehicle wheel hub, which can be closed to the outside by a cap; wherein the cap is shown graphically at a certain distance from the edge of the wheel hub;

2 a partial section through the edge of the hub and the cap, namely with locked cap;

3 in a schematic representation of the one hand on the edge of the hub and on the other hand on the cap formed structures on the one hand the bayonet connection and on the other hand an additional safeguard against twisting;

4a - 4c the structures in a plan view and in three different variants;

5a - 5c the structures in one of 3 comparable representation, and again in the three also in the 4a - 4c reproduced variants;

6 in a further embodiment of the invention, a partial cross-section through the edge of the wheel hub and the cap;

7a - 7c In a further embodiment of the invention, longitudinal sections through the edge of the wheel hub and the cap, wherein the parts in 7a before unscrewing, in 7b after partial unscrewing, and in 7c are shown after screwing including the anti-rotation device;

8th a partial cross section according to the in 7a Plotted sectional plane VIII;

9 a partial cross section according to the in 7c Plotted sectional plane IX and

10 for the embodiment according to the 7a to 9 in a schematic representation of the one hand on the edge of the hub and on the other hand formed on the cap structures in three peripheral areas.

The 1 shows in perspective the bearing-side end of a commercial vehicle axle and in particular the axis of a towed vehicle, such. B. a truck trailer or -aufliegers. Enclosed by the hub body 6 the wheel hub 1 is the wheel bearing of the vehicle axle. On the outer circumference of the wheel hub 1 are bores as fasteners 2 provided for the vehicle wheel and / or the brake drum or the brake disc. After axially outward, the hub body runs 6 the wheel hub 1 in a fret or edge 3 out, in the center of which, not shown on the drawing, which is the rolling bearing locking central axle nut. To close the opening 7 the wheel hub is on its edge 3 in the 1 with distance to the edge 3 illustrated cap 4 placed. Their attachment to the edge 3 forms the technical object of the present innovation. It should be added that the cap 4 may be provided with an odometer, which mechanically or electronically revolutions of the wheel hub 1 recorded and used to calculate the mileage. Such in hub caps integrated "Hubodometer" are known.

The cap 4 has approximately the shape of a pot. It is designed relatively thin-walled and made in metal or in plastic by deep drawing. Locking and latching structures, which are explained in more detail below, can be molded onto the cover during the manufacturing process. The wheel hub 1 facing, has the cap 4 an approximately annular, cylindrical wall portion 5 on. Dieer surrounds the edge at least over part of its axial length 3 the wheel hub 1 ,

According to 2 is in the edge 3 the wheel hub 1 a circumferential groove incorporated, in which a sealing ring 8th sitting. This is supported from the inside against the annular wall section 5 the cap 4 and prevents in this way penetration of dirt and dust into the interior of the wheel hub 1 and thus in the area of the local wheel bearing.

The wheel hub is near its outer edge 3 with another circumferential groove 9 provided, whereby an outwardly projecting radial collar 10 remains. At the back of the Radialbund 10 This is an undercut 11 , at which with locked hub cover a corresponding projection 12 the cap 4 can come to the plant. In this projection 12 it is a deformation of the annular wall portion 5 the cap. The relatively thin-walled material of the cap 4 is pressed inwards or put through. In a view from inside approximately triangular-looking projections 12 are also in 1 to recognize, however, viewed from the outside. About the circumference of the cap 4 considered, this is in the embodiment according to 1 with a total of five such projections 12 provided, wherein these are arranged at equal angular intervals to each other.

As 2 can recognize the cap is held in the manner of a bayonet to the wheel hub by the projections 12 behind the Radialbund behind the form-fitting behind 10 formed undercuts 11 to grab. Locked so, therefore, the cap can 4 not axially from the wheel hub 1 to solve. For this purpose, a rotary unlocking of the bayonet is required, which will be explained in more detail below.

3 shows the conditions in a simplified for the sake of illustration embodiment in which distributed over the circumference of the wheel hub not five bayonet structures are present, but only three. Shown is inside the Radialbund 10 the wheel hub, wherein it is noticeable that the radial extent of the Radialbundes 10 segmentally larger and smaller. In the relatively long segment areas 10a the radial collar has its greatest radial extent. In these segments 10a also takes the positive engagement by the respective projection 12 , wherein according to the simplified representation of 3 analogous to the three segment areas here 10a also three projections 12 exist.

To achieve the desired axial securing 23 when attaching the cap to the hub, the projections must 12 in the position or angular position 12.1 located in 3 hatched. This angular position is indicated by markings 13 the wheel hub 1 (please refer 2 ) is displayed. When setting up, therefore, the respective projection 12 in longitudinal alignment with one of the markings 13 be. In the angular position 12.1 is the Radial Union 10 through a recess 16 interrupted, the axial passage of the projection 12 allows. Once the lead 12 through this recess 16 is passed axially, then carried a rotation of the cap 4 clockwise. This gives the lead 12 from the position 12.1 in the in 3 also shown position 12.2 , In position 12.2 is the lead 12 positively behind the segment area 10a of the Radial Union 10 locked. Of course, the same applies to the other projections 12 whose angular distance to the respective next or preceding projection is the same in each case, as well as the angular spacing of the recesses 16 ,

In contrast, should a certain position of the cap 4 opposite the wheel hub 1 may be required, different angular distances or segments segments of different lengths 10a to be available.

The described axial securing 23 through the projections 12 or corresponding radial bünde 10a However, would not be sufficient to in driving, and in particular in the case of shocks unwanted twisting of the cap 4 and thus a release of the cap 4 to prevent. Because neither within the positive rotation lock 22 , still within the positive axial locking 23 acts with mounted cap 4 a permanent holding power. This is not necessary. Because to secure against accidental free rotation is such a rotation 22 provided as follows, also on the basis of 3 is explained.

Inside the annular wall section 5 the cap 4 are locking elements 18 , These are like the tabs 12 arranged distributed at equal angular intervals to each other over the circumference of the hub cover. The locking elements 18 extend radially less far inward than the projections 12 , According to the embodiment 3 are analogous to the three protrusions 12 also three locking elements 18 intended. The number of projections and locking elements should therefore match. However, a number of five projections is particularly advantageous for the hub cover of the axle of a heavy duty vehicle 12 , Which then also the number of locking elements 18 is five. Also the production of the locking elements 18 is preferably carried out by appropriate cold deformation of the relatively thin-walled wall material of the cap 4 ,

The 4a to 4c let recognize that the locking elements 18 have an elongated and in particular oval shape. Your long edges 19 extend in the circumferential direction between 0 ° and 25 ° to the axis of rotation 20 the wheel bearing bent. In 4a this angle w is registered.

Each of the locking elements 18 is part of a fuse whose other component is a wheel hub 1 molded fuse area A, B, C is. The fuse area A is composed, as viewed in the circumferential direction, of five consecutive segments A1, A2, A3, A4 and A5. The sequence of these individual segments A1-A5 is in the in 3 a total of three hedges A, B and C not uniform, but uneven. Thus, the securing area A has segments A1, A2 and A3, in which the radial extent R2 of the radial collar 10 each is the same. In segment A4, on the other hand, the radial collar is increased compared to the segments A1-A3, its radial extent is R1. Segment A5 in turn corresponds to the recess already described 16 in the Radial Union 10 , Here, the radial height R3 of the radial collar is the lowest. A look at the 3 shows that in the other two security areas B and C, the sequence is different in that the order of the different radii of the segments is different. In the backup area B, the segment B2 has the increase R1, and in the security area C the segment C3. The radial steps between the segments of different heights are rounded or chamfered, in order to achieve a certain clamping effect, but without real locking occurring during turning beyond the temporary clamping.

It is crucial that the locking element 18 extends radially beyond that radius R1 up to which the radially outermost extending segment (at the top left this is the segment A4) extends. This has the consequence that when turning the cap 4 the locking element 18 strikes against the most radially projecting segment A4, B2 and C3, and further rotation is possible only by overcoming a deformation resistance. This is due to a deformation of the reversibly deformable due to their relatively small wall thickness, usually round cap 4 reached.

• a) der Widerstand durch Formänderung der Abdeckkappe 4 ist nicht so groß, dass er nicht mit einem entsprechenden Werkzeug (jedoch nicht ohne Werkzeug) überwunden werden könnte;
• b) die vorübergehende Verklemmung bzw. Verrastung tritt nacheinander in drei unterschiedlichen Winkellagen auf, was die Sicherheit gegen ein ungewolltes Freidrehen der Abdeckkappe noch erhöht.

Since the radially most projecting segments A4 and B2 or C3 are arranged relative to each other at different angular positions, the increased torsional resistance associated with the temporary jamming of the structures occurs not only once but several times in succession and at different angular positions. This has two advantages:

• a) the resistance by changing the shape of the cap 4 is not so big that it could not be overcome with an appropriate tool (but not without tools);
• b) the temporary jamming or latching occurs successively in three different angular positions, which increases the security against unintentional free rotation of the cap.

Provided, what kind of the practice is preferred, the number of distributed coverage areas is five, it would be theoretical possible, correspondingly many differently designed security areas with an adapted number of segments. This however, is not essential. Practice has shown that's five, too Secured areas is sufficient, only three different Provide segment sequences. In this case, therefore, individual backup areas quite similar designed with the same sequence of segments be.

These three variants are in the 4a - 4c in plan view, and in the 5a to 5c again in one of the 3 similar sectional view shown. It can also be seen that when locked cap the locking element 18 in the recess 16 and at the same time in that segment A5, B5, C5, in which the radial collar 10 has no or at least the smallest radial extent R3. This segment A5, B5, C5 also serves in the release state the unimpeded axial passage of the respective projection 12 and is dimensioned accordingly.

There are further arrangement variants conceivable. For example, the securing areas A, B, C can also be introduced into the cap and the projections 18 be formed as part of the hub. The bayonet elements can be designed accordingly replaced. Also conceivable is a separate arrangement of the securing area in the direction of rotation and the bayonet structure, so that the recess 16 do not have to fulfill a double function. Contrary fulfilled, as in 6 shown, an L-shaped projection both form-fit functions, the short L-leg with a longer radial extent behind the undercut 11 as a lead 12 engages, and thus secures axially. The long L-leg with less long radial extension takes over the segments as a projection 18 the rotation lock. head Start 12 and lead 18 lie axially behind one another.

From the 4a - 4c also opens up the meaning of the advantage of the oblique arrangement of the locking elements 18 at the angle w. If a release torque is exerted on the cap, arises due to the oblique longitudinal edges 19 a force component to the outside when the projection 12 into the recess 16 passes and the longitudinal edge 19 at the side edge of the segment area 10a slips past. The cap 4 can then easier in the longitudinal direction of the wheel hub 1 to solve. In this way, in particular by the sealing ring 8th overcome, caused axial release resistance easier.

According to 4b extend the locking elements 18 corresponding to the longitudinal dimension L1 farther away from the open edge 21 the cap, as the projections 12 in which the longitudinal dimension is L2. Only then is the temporary jamming or locking of the locking elements 18 along the Radialbund 10 scored, whereas the projections 12 behind the Radialbund 10 respectively. 10a are located.

At the in 6 in a partial cross-section illustrated embodiment are the projection 12 and the locking element 18 in the circumferential direction in the same angular position on the wall portion 5 arranged the cap. The in turn radially further inwardly projecting projection 12 is located in 6 behind the less far radially projecting locking element 18 , In this way, the lead engages behind 12 the formed on the hub radial collar, whereas the locking element 18 in the manner already described with the individual segments of the security area A cooperates. These segments are in turn as different areas of the Radialbundes 10 educated.

A difference from the previously described embodiment is also that the recess 16 through which the projection 12 the cap can pass axially, located in the segment A1. There is corresponding reference radius R3. A temporary jamming or latching of the locking element 18 takes place on the other hand in the segments A2, A3 and A4, with segment A4 protrudes with the reference radius R1 farthest radially outwards, and therefore represents the greatest resistance to the rotation lock.

In the 7a to 10 another embodiment is shown. Here, the axial securing takes place 23 the cap is not a bayonet, but by means of a screw 30 , For this purpose is located on the edge of the annular wall section 5 the cap an internal thread 31 , and on the edge 3 the wheel hub a corresponding external thread 32 , At the edge 3 are even further outward than the external thread 32 , the fuse areas A, B, C arranged. The 9 in which it is a partial sectional view corresponding to the sectional plane IX in 7c shows the interaction between the segment area A and formed on the cover locking element 18 in the secured position or angular position.

1

wheel hub

2

fastener

3

edge

4

cap

5

annular wall section

6

Hub body

7

opening

8th

seal

9

circumferential groove

10

radial collar

10a

segment area of the Radial Union

11

undercut

12

head Start

12.1

Position, angular position

12.2

Position, angular position

13

mark

16

recess

18

locking element

19

longitudinal edge

20

axis of rotation

21

edge the cap

22

rotation

23

axial safety

30

screw

31

inner thread

32

external thread

A

security area

B

security area

C

security area

L1

axial measure

L2

axial measure

R1

radius

R2

radius

R3

radius

A1-A5

segments

B1-B5

segments

C1-C5

segments

w

angle

Claims (28)

Cover for a wheel bearing, with one on a wheel hub ( 1 ) of a vehicle wheel by turning attachable cap ( 4 ), characterized by a plurality over the circumference of the hub cover distributed securing areas (A, B, C) of a rotation lock ( 22 ), wherein the fuse areas (A, B, C) are circumferentially subdivided into consecutive segments (A1-A5, B1-B5, C1-C5) of nonuniform radial extent, and the sequence of segments (A1-A5, B1-B5 , C1-C5) in at least two of the fuse areas (A, B, C) is different from each other. Hub cover according to claim 1, characterized in that the rotary attachment is designed as a bayonet connection, which extends onto a plurality of bayonet structures distributed over the circumference of the hub cover ( 10a . 12 ). Hub cover according to Claim 1 or Claim 2, characterized by a latching element which cooperates radially with the respective securing region (A, B, C) ( 18 ) projecting radially beyond that radius (R1) to which the radially outermost segment (A4; B2; C3) extends. Hub cover according to one of claims 1 to 3, characterized in that the transitions between the radially rounded segments of different lengths are rounded. Hub cover according to one of claims 1 to 4, characterized in that the latching element ( 18 ) is an elongated projection preferably made by material deformation. Hub cover according to claim 5, characterized in that at least one of the longitudinal edges ( 19 ) of the locking element ( 18 ) in the circumferential direction between 0 ° and 25 ° to the axis of rotation ( 20 ) of the wheel bearing is angled. Hub cover according to one of claims 3 to 6, characterized in that that part of the hub cover on which the securing elements ( 18 ) are formed, is deformable. Hub cover according to claim 7, characterized in that the securing elements ( 18 ) on the inside at an annular wall portion ( 5 ) of the cap ( 4 ) are formed, which is deformable from a round in a slightly non-circular shape. Hub cover according to one of claims 2 to 8, characterized in that part of each bayonet structure on the cover ( 4 ) formed inside projection ( 12 ), preferably a by material deformation of the cap ( 4 ) produced projection. Hub cover according to claim 9, characterized in that part of each bayonet structure is one on a radial collar ( 10 . 10a ) of the wheel hub ( 1 ) formed undercut ( 11 ) and that the Radialbund ( 10 ) is extended circumferentially beyond the bayonet structure area to form the radially nonuniformly extending segments (A1-A5, B1-B5, C1-C5) of the fuse area (A, B, C). Hub cover according to claim 10, characterized in that both the latching element ( 18 ) as well as the lead ( 12 ) inside the cap ( 4 ) are formed, and that the locking element further from the open edge ( 21 ) of the cap ( 4 ) extends away (axial dimension L1), as the projection (axial dimension L2). Hub cover according to one of the preceding claims, characterized by a sealing ring ( 8th ) between the inside of the cap ( 4 ) and the wheel hub ( 1 ). Hub cover according to one of claims 2 to 12, characterized in that the bayonet structures ( 10a . 12 ) are similarly designed and distributed at equal angular intervals to each other over the circumference of the hub cover. Hub cover according to one of the preceding claims, characterized characterized in that the fuse areas (A, B, C) in the same angularly over each other the circumference of the hub cover are arranged distributed. Hub cover according to one of the preceding claims, characterized characterized in that at least two of the fuse areas (A, B, C) are similar, d. H. with the same sequence of segments designed are. Hub cover according to one of claims 2 to 15, characterized in that the number the fuse areas (A, B, C) equal to the number of bayonet structures ( 10a . 12 ). Hub cover according to one of claims 11 to 16, characterized in that the projection ( 12 ) extends radially further inward than the locking element ( 18 ). Wheel hub for a vehicle wheel, with a hub body ( 6 ) for receiving a wheel bearing to the hub body ( 6 ) arranged around fasteners ( 2 ) for the vehicle wheel, as well as a central opening ( 7 ) surrounding the wheel hub, axially outwardly projecting edge ( 3 ) having structures formed thereon for pivotally mounting a cap, characterized by a plurality over the circumference of the edge ( 3 ) distributed fuse areas (A, B, C) of a rotation lock ( 22 ), wherein the fuse areas (A, B, C) are circumferentially subdivided into consecutive segments (A1-A5, B1-B5, C1-C5) of nonuniform radial extent, and the sequence of segments (A1-A5, B1-B5 , C1-C5) in at least two of the fuse areas (A, B, C) is different from each other. Wheel hub according to claim 18, characterized that the transitions between rounded radially differently extending segments are. Wheel hub according to claim 18 or 19, characterized in that at the edge ( 3 ) formed structures bayonet structures ( 10a . 16 ) are. Wheel hub according to claim 20, characterized by a on a radial collar ( 10 . 10a ) of the edge ( 3 ) formed undercut ( 11 ), whereby the Radialbund ( 10 ) in the circumferential direction over the area of the bayonet structure ( 10a . 16 ) is extended to form the radially nonuniformly extending segments (A1-A5, B1-B5, C1-C5) of the fuse region (A, B, C). Wheel hub according to claim 20 or 21, characterized in that the bayonet structures ( 10a . 16 ) are similarly designed and at equal angular intervals to each other over the circumference of the edge ( 3 ) are arranged distributed. Wheel hub according to one of claims 18 to 22, characterized in that the securing areas (A, B, C) at equal angular distances from each other over the circumference of the edge ( 3 ) are arranged distributed. Wheel hub according to one of claims 18 to 23, characterized that at least two of the security areas (A, B, C) are similar, d. H. with the same sequence of segments are designed. Wheel hub according to one of Claims 18 to 24, characterized in that the number of securing areas (A, B, C) is equal to the number of bayonet structures (A, B, C). 10a . 16 ). Cover cap for rotatable mounting via bayonet structures on a circumferential edge of a wheel hub, wherein a component of each bayonet structure is attached to an annular wall section ( 5 ) of the cap ( 4 ) arranged projection ( 12 ), characterized in that on the same wall section ( 5 ) Locking elements ( 18 ) are arranged, that the locking elements ( 18 ) on different angular positions than the projections ( 12 ) are arranged, and that the locking elements ( 18 ) farther from the open edge ( 21 ) of the cap ( 4 ) than the projections ( 12 ). Covering cap according to claim 26, characterized in that the projections ( 12 ) radially further inwardly than the locking elements ( 18 ). Cover with a wheel hub ( 1 ) and on it by turning simultaneously against loosening positively locked and axially secured cap ( 4 ), characterized by a local separation between a positive rotation lock ( 22 ) and a positive axial locking ( 23 ) between wheel hub ( 1 ) and cap ( 4 ).