Wheel hub unit with thermally insulating coating for reducing the thermal load on a wheel bearing

Patent metadata

Field	Value
Publication number	US-2019024743-A1
Application number	US-201816041992-A
Country	US
Kind code	A1
Filing date	Jul 23, 2018
Priority date	Jul 21, 2017
Publication date	Jan 24, 2019
Grant date	—

Abstract

The present disclosure relates to a wheel hub unit of a motor vehicle and to a method for producing such a wheel hub unit. The wheel hub unit includes a wheel hub and a contact flange firmly connected to the wheel hub. The contact flange includes a plurality of fastening elements for fastening a wheel rim, as well as a contact surface which is intended to come into mechanical contact, at least in part, with a brake hat of a brake disk when the brake disk is in the mounted state. At least part of the contact surface is provided with a thermally insulating coating. Alternatively, the entire contact surface is provided with the thermally insulating coating.

First claim

What is claimed is:

1 . A wheel hub unit comprising:
a wheel hub; and a contact flange connected to the wheel hub and comprising a contact surface configured to come into mechanical contact with at least one part of a brake hat of a brake disk when the brake disk is in a mounted state, wherein part of the contact surface includes a thermally insulating coating on at least one of a circumferential surface of the wheel hub and a circumferential surface of the contact flange.

2 . The wheel hub of claim 1 , wherein the contact flange includes a plurality of fastening elements configured to fasten the wheel hub unit to a wheel rim.

3 . The wheel hub unit of claim 1 , wherein the thermally insulating coating is an enamel coating.

4 . The wheel hub unit of claim 3 , wherein the enamel coating comprises 50% to 80% SiO 2 .

5 . The wheel hub unit of claim 3 , wherein the enamel coating comprises 10-50% to 30% ZrO 2 .

6 . The wheel hub unit of claim 3 , wherein the enamel coating comprises 1% to 10% oxide selected from the group consisting of oxides B 2 O 3 , Al 2 O 3 , CuO, and Na 2 O.

7 . The wheel hub unit of claim 3 , wherein the enamel coating comprises 65% SiO 2 , 5% B 2 O 3 , 5% Al 2 O 3 , 18% ZrO 2 , 5% CuO and 2% Na 2 O.

8 . The wheel hub unit of claim 1 , wherein the thermally insulating coating defines a film thickness between 150 μm and 700 μm.

9 . The wheel hub unit of claim 1 , wherein the thermally insulating coating has a thermal conductivity of less than 2.0 W/(m·K) at a temperature above 350° C.

10 . The wheel hub unit of claim 1 , wherein the thermally insulating coating is free of antimony, gallium, indium, molybdenum, hafnium, bismuth, rare earth metals, and compounds thereof.

11 . The wheel hub unit of claim 1 , wherein a brake disk made from at least one aluminum alloy is detachably connected to the contact flange.

12 . A method for producing the wheel hub unit of claim 1 , the method comprising:
providing a wheel hub blank made of gray cast iron; producing the contact surface of the contact flange by machining; treating the contact surface at least by blasting with a blast material; applying an enamel slip to at least one part of the contact surface; drying the enamel slip; heating the wheel hub blank to a temperature of above 720° C.; and finishing the wheel hub unit by machining to a predetermined dimension.

13 . A wheel hub unit comprising:
a wheel hub; a contact flange connected to the wheel hub; and a contact surface formed by a circumferential surface and an annular surface of the contact flange and part of a circumferential surface of the wheel hub, wherein the contact surface includes a thermally insulating coating.

14 . The wheel hub unit of claim 13 further comprising a brake disk having a brake hat and detachably connected to the contact flange, wherein the contact surface is configured to come into mechanical contact with at least a portion of the brake hat of the brake disk.

15 . The wheel hub unit of claim 14 , wherein the thermally insulating coating of the contact surface has a thermal diffusivity of less than 10% of a thermal diffusivity of a material of the brake disk at a temperature above 350° C.

16 . The wheel hub unit of claim 13 , wherein a thickness of the thermally insulating coating is between 150 μm and 700 μm and a thermal conductivity of the thermally insulating coating is less than 2.0 W/(m·K) at a temperature above 350° C.

17 . The wheel hub unit of claim 13 , wherein a thickness of the thermally insulating coating is between 200 μm and 600 μm.

18 . The wheel hub unit of claim 13 , wherein the thermally insulating coating of the contact surface is an enamel coating.

19 . The wheel hub unit of claim 18 , wherein the enamel coating comprises:
50% to 80% SiO 2 ; 10% to 30% ZrO 2 ; and 1% to 10% oxide selected from the group consisting of oxides B 2 O 3 , Al 2 O 3 , CuO, and Na 2 O.

20 . The wheel hub unit of claim 19 , wherein the enamel coating comprises 65% SiO 2 , 18% ZrO 2 , 5% B 2 O 3 , 5% Al 2 O 3 , 5% CuO and 2% Na 2 O.

Assignees

• Ford Global Tech Llc

Inventors

• Rettig Marc Oliver
• Wilwers Thomas
• Verpoort Clemens
• Voss Eckhard

Classifications

• F16D65/127

  characterised by properties of the disc surface; Discs lined with friction material · CPC title

• F16D65/125

  characterised by the material used for the disc body · CPC title

• F16D2200/003

  Light metals, e.g. aluminium · CPC title

• C23D5/02 Primary

  by wet methods · CPC title

• F16C33/605

  with a separate retaining member, e.g. flange, shoulder, guide ring, secured to a race ring, adjacent to the race surface, so as to abut the end of the rolling elements, e.g. rollers, or the cage · CPC title