Wheel bearing unit for a motor vehicle as well as method for producing a wheel bearing unit

Abstract

A wheel bearing unit for a motor vehicle, having a wheel hub, a wheel bearing flange, and a wheel bearing for pivot mounting of the wheel hub on the wheel bearing flange. The wheel hub has a passage opening for mounting a shaft journal attached to the wheel hub by a screw connection element, and an inner toothing is formed, on an inner circumferential surface delimiting the passage opening, for rotationally fixed interaction with an outer toothing of the shaft journal, and the passage opening extends through a contact shoulder, which is formed so as to have contact with a contact surface of the screw connection element, with the formation of an orifice.

Claims

1. A wheel bearing unit for a motor vehicle, comprising: a wheel hub, a wheel bearing flange, and a wheel bearing for pivot mounting of the wheel hub on the wheel bearing flange, wherein the wheel hub has a passage opening for mounting a shaft journal attached to the wheel hub by a screw connection element, and an inner toothing is formed, on an inner circumferential surface delimiting the passage opening, for rotationally fixed interaction with an outer toothing of the shaft journal, and wherein the passage opening extends through a contact shoulder, which is formed so as to have contact with a contact surface of the screw connection element, with the formation of an orifice, wherein in order to enlarge the contact shoulder, the inner toothing is formed on the inner circumferential surface up to the orifice such that an inner diameter corresponds to at least a tip diameter of the inner toothing and is less than a root diameter of the inner toothing, and wherein the inner toothing has a first toothing region present in the orifice and a second toothing region spaced apart from the first toothing region in the axial direction as relates to a center longitudinal axis of the passage opening, between which toothing regions a section of the passage opening is formed with an inner diameter which is greater than the tip diameter of the inner toothing, wherein the shaft journal engages the second toothing region completely and protrudes into the section of the passage opening, but ends spaced apart from the first toothing region.

2. The wheel bearing unit according to claim 1, wherein the inner diameter in the section of the passage opening corresponds, at least in regions, to at least the root diameter such that the inner toothing is interrupted in the section.

3. The wheel bearing unit according to claim 2, wherein the inner diameter of the section enlarges starting from the first toothing region up to a maximum diameter and subsequently reduces up to the second toothing region.

4. The wheel bearing unit according to claim 2, wherein the section has an extension in the axial direction which corresponds to or is greater than or less than an extension of the second toothing region in the same direction, and/or wherein the first toothing region has an extension in the axial direction which is less than the extension of the second toothing region or the section in the same direction.

5. The wheel bearing unit according to claim 2, wherein the shaft journal engages the passage opening by a further orifice facing away from the orifice in the axial direction and ends either spaced apart from the orifice or extends completely through the passage opening and protrudes through the orifice from the passage opening.

6. The wheel bearing unit according to claim 1, wherein the inner diameter of the section enlarges starting from the first toothing region up to a maximum diameter and subsequently reduces up to the second toothing region.

7. The wheel bearing unit according to claim 6, wherein the section has an extension in the axial direction which corresponds to or is greater than or less than an extension of the second toothing region in the same direction, and/or wherein the first toothing region has an extension in the axial direction which is less than the extension of the second toothing region or the section in the same direction.

8. The wheel bearing unit according to claim 6, wherein the shaft journal engages the passage opening by a further orifice facing away from the orifice in the axial direction and ends either spaced apart from the orifice or extends completely through the passage opening and protrudes through the orifice from the passage opening.

9. The wheel bearing unit according to claim 1, wherein the section has an extension in the axial direction which corresponds to or is greater than or less than an extension of the second toothing region in the same direction, and/or wherein the first toothing region has an extension in the axial direction which is less than the extension of the second toothing region or the section in the same direction.

10. The wheel bearing unit according to claim 9, wherein the shaft journal engages the passage opening by a further orifice facing away from the orifice in the axial direction and ends either spaced apart from the orifice or extends completely through the passage opening and protrudes through the orifice from the passage opening.

11. The wheel bearing unit according to claim 1, wherein the shaft journal engages the passage opening by a further orifice facing away from the orifice in the axial direction and ends either spaced apart from the orifice or extends completely through the passage opening and protrudes through the orifice from the passage opening.

12. The wheel bearing unit according to claim 1, wherein the further orifice lies completely within an imaginary plane which is perpendicular to the center longitudinal axis, wherein the imaginary plane completely encompasses a contact surface for a coupling device having a shaft journal and is arranged spaced apart from the second toothing region in the axial direction.

13. A method for producing a wheel bearing unit for a motor vehicle, wherein the wheel bearing unit has a wheel hub, a wheel bearing flange, and a wheel bearing for pivot mounting of the wheel hub on the wheel bearing flange, wherein the wheel hub has a passage opening for mounting a shaft journal attached to the wheel hub by a screw connection element, and an inner toothing is formed, on an inner circumferential surface delimiting the passage opening, for rotationally fixed interaction with an outer toothing of the shaft journal, and wherein the passage opening extends through a contact shoulder, which is formed so as to have contact with a contact surface of the screw connection element, with the formation of an orifice, wherein in order to enlarge the contact shoulder, the inner toothing is formed on the inner circumferential surface up to the orifice such that an inner diameter of the orifice corresponds to at least a tip diameter of the inner toothing and is less than a root diameter of the inner toothing, and wherein the inner toothing has a first toothing region present in the orifice and a second toothing region spaced apart from the first toothing region in the axial direction as relates to a center longitudinal axis of the passage opening, between which toothing regions a section of the passage opening is formed with an inner diameter which is greater than the tip diameter of the inner toothing, wherein the shaft journal engages the second toothing region completely and protrudes into the section of the passage opening, but ends spaced apart from the first toothing region.

14. The method according to claim 13, wherein the inner toothing is formed from broaching, wherein a broaching tool extends completely through the passage opening.

15. The method according to claim 13, wherein the section is provided, before the broaching, with the inner diameter which is greater than the tip diameter of the inner toothing.

Description

DETAILED DESCRIPTION

(1) The FIGURE shows a schematic longitudinal section of a wheel bearing unit 1 for a motor vehicle. The wheel bearing unit 1 has a wheel bearing flange 2, on which a wheel hub 4 is rotatably mounted via a wheel bearing 3. A wheel of the motor vehicle can ultimately be attached to the wheel hub 4 such that, after its assembly, the wheel is rotatably mounted as relates to the wheel bearing flange 2 by means of a body of the motor vehicle. The wheel bearing 3 is formed as a roller bearing and has, in this respect, roller elements 5 which are arranged between an inner ring 6 and an outer ring 7 of the wheel bearing 3. In the exemplary embodiment shown here, the inner ring 6 is designed with the wheel hub 4 as a single piece and with uniform material, and the outer ring 7 is designed with the wheel bearing flange 2 as a single piece and with uniform material. Of course, the inner ring 6 and the outer ring 7—optionally in each case—may also be in the form of separate elements which are arranged on and/or attached to the wheel hub 4 and/or the wheel bearing flange 2.

(2) The wheel hub 4 has a passage opening 8, in which a screw connection element formed as a screw 10 and, on the other side, a shaft journal, which is not shown here, of the coupling device engage in the axial direction as relates to a center longitudinal axis 9 of the passage opening 8. The screw 10 is used to affix the shaft journal in the passage opening 8. Alternatively, the screw connection element may be formed as a nut for this. The screw 10 extends through an orifice 11 of the passage opening 8, and the shaft journal extends through a further orifice 12. Orifices 11 and 12 delimit the passage opening 8 in the axial direction. The passage opening 8 is delimited outwardly on opposite sides in the radial direction by an inner circumferential surface 13.

(3) An inner toothing 14 is formed on the inner circumferential surface 13, which inner toothing is provided and formed to interact with an outer toothing of the shaft journal in a rotationally fixed manner. The inner toothing 14 is formed at least in a first toothing region 15 and a second toothing region 16 which are spaced apart from one another in the axial direction as relates to the center longitudinal axis 9. As seen in the axial direction, a section 17 of the passage opening 8 is situated between toothing regions 15 and 16.

(4) A screw connection mount 18, which is used as a mount of a screw head 19 of the screw 10, is situated on the side of the orifice 11 facing away from the passage opening 8. After assembly of the wheel bearing unit 1, the screw head 19 is situated on a contact shoulder 20, which encompasses the orifice 11 in the circumferential direction at least partially, but preferably completely. The contact shoulder 20 is preferably continually planar and situated completely in an imaginary plane which also completely encompasses the orifice 11.

(5) The contact shoulder 20 is formed, at least in regions, by teeth 21 of the inner toothing 14 of the first toothing region 15. To this end, the inner toothing 14 extends up to the orifice 11.

(6) This means that the contact shoulder 20 encompasses the orifice 11 in the manner of a ring. On the side of the wheel hub 4 opposite the contact shoulder 20, a contact surface 22 fits closely therewith, which contact surface serves to support the coupling device, which is not shown, in the axial direction. After assembly of the wheel bearing unit 1, the screw head 19 fits closely with the contact shoulder 20, and the coupling device fits closely with the contact surface 22, while the screw 10 simultaneously engages a shaft journal of the coupling device in a fixing manner, which shaft journal protrudes through the further orifice 12 into the passage opening 8. In this respect, the shaft journal and/or the coupling device is securely affixed to the wheel hub 4 in the axial direction by means of the screw 10. In addition, the shaft journal and the wheel hub 4 are established against each other due to the interaction of the inner toothing 14 with the outer toothing of the shaft journal.

(7) In order to achieve an especially economical production of the wheel bearing unit 1 and particularly the wheel hub 4, the inner toothing 14 should be formed by means of broaching, wherein a broaching tool is guided through the passage opening 8. This means that the orifice 11 must have a correspondingly large diameter. In order to still achieve sufficient fatigue strength of the wheel bearing unit 1, the contact shoulder 20—as previously mentioned—should be formed, at least partially, by the teeth 21 of the inner toothing 14 of the first toothing region 15. This means that an inner diameter D.sub.i of the passage opening 8 in the first toothing region 15 corresponds at least to a tip diameter D.sub.K of the inner toothing 14 and is less than a root diameter D.sub.F of the inner toothing 14. In other words, the following holds true: D.sub.K≤D.sub.i<D.sub.F.

(8) In order to achieve an especially low strain on the broaching tool and additionally to design the wheel bearing unit 1 to be as lightweight as possible, it is additionally provided that the passage opening 8 in the section 17 has an inner diameter which is greater than the tip diameter D.sub.K of the inner toothing 14. Preferably, it is provided that the inner diameter of the section 17 enlarges starting from the first toothing region 15 up to a maximum diameter D.sub.m and subsequently reduces again up to the second toothing region 16. The maximum diameter D.sub.m in this case is at least greater than the tip diameter D.sub.K of the inner toothing 14; however, it especially preferably corresponds at least to the root diameter D.sub.F. The latter case means that the inner toothing 14 in the section 17 is not even rudimentarily formed to the extent that the inner toothing 14 in the section 17 is interrupted, at least in regions.

(9) The described embodiment of the wheel bearing unit 1 enables an especially economical and simple design, on the one hand, and has an especially low weight, on the other hand.

LIST OF REFERENCE NUMERALS

(10) 1 Wheel bearing unit 2 Wheel bearing flange 3 Wheel bearing 4 Wheel hub 5 Roller element 6 Inner ring 7 Outer ring 8 Passage opening 9 Center longitudinal axis 10 Screw 11 Orifice 12 Orifice 13 Inner circumferential surface 14 Inner toothing 15 1st toothing region 16 2nd toothing region 17 Section 18 Screw connection mount 19 Screw head 20 Contact shoulder 21 Teeth 22 Contact surface