Hub unit, hub unit manufacturing method and hub unit transporting method

Abstract

A hub unit is configured such that nitrogen gas, which functions as inert gas, is filled in a rolling element arranging space which is defined by an inner circumferential surface of an outer ring and an outer circumferential surface of a hub wheel for arranging rolling elements therein in such a manner as to be sealed therein in a semi-hermetically closed state by a seal member and a cover, so as to prevent the nitrogen gas from flowing out to an exterior space. The seal member, which is provided at an end portion of the rolling element arranging space which end lies on a vehicle-outer side, is formed as an elastic seal element, and is fixed to the outer ring at one end whereas being secured to the hub wheel at the other end thereof while being elastically deformed, whereby the seal member has a function to prevent the intrusion of water from the exterior space into the rolling element arranging space. This seal member prevents the inert gas filled in the rolling element arranging space from flowing out to the outside.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing a hub unit of Embodiment 1 of the invention.

FIG. 2 is a sectional view which describes a method for manufacturing the hub unit of Embodiment 1.

FIG. 3 is a sectional view showing a hub unit of Embodiment 2 of the invention.

FIG. 4 is a sectional view showing a main part of FIG. 3.

FIG. 5 is a sectional view showing a hub unit of Embodiment 3 of the invention.

FIG. 6 is a diagram which describes a method for manufacturing the hub unit of Embodiment 3.

FIG. 7 is a diagram showing a method for transporting hub units which are transported in such a state that they are mounted on vehicles.

Claims

1. A hub unit comprising: an outer ring member which is stationarily attached to a main body of a vehicle; anda hub wheel which is attached to a wheel of the vehicle and is disposed concentrically and rotatably with respect to the outer ring member around an axis of the hub wheel via rolling elements such that a rolling element arranging space is defined between the outer ring member and the hub wheel along an axial direction of the hub wheel;wherein a seal member for sealing the rolling element arranging space is provided at one or both of end portions of the rolling element arranging space which lie in the axial direction on a vehicle-outer side and a vehicle-inner side, whereby the rolling element arranging space is made to have a semi-hermetically closed construction which has no other leak path through which a gas within the rolling element arranging space leaks out to the outside of the hub unit than a sealing surface by the seal member; andan inert gas being filled in the rolling element arranging space.

2. The hub unit according to claim 1, wherein the seal member is disposed to be elastically compressed between the outer ring member and the hub wheel, and the inert gas is filled in the rolling element arranging space in a pressurized state, and the seal member maintains a sealing state between the outer ring member and the hub wheel against a pressure generated by the pressurized inert gas.

3. The hub unit according to claim 1, wherein the seal member doubles as a water intrusion preventive member which prevents an intrusion of water into the rolling element arranging space.

4. The hub unit according to claim 1, wherein the hub unit is served in a driven wheel of the vehicle, and further includes the seal member disposed at the vehicle-outer side end portion of the rolling element arranging space and having a cover mounted at the vehicle inner-side end portion to prevent the inert gas filled in the rolling element arranging space from flowing out to the exterior space.

5. The hub unit according to claim 1, wherein a gas filling hole is formed in the outer ring member so as to pass radially therethrough from an outer circumferential surface thereof into the rolling element arranging space, and the inert gas is filled from the gas filling hole, and the gas filling hole is closed with a sealing material after the inert gas is filled up.

6. The hub unit according to claim 5, wherein the gas filling hole is made to function as a sensor arranging hole.

7. A method for manufacturing the hub unit according to claim 1, comprising a step of defining the rolling element arranging space by assembling together the outer ring member, the rolling elements, the hub wheel and the seal member, wherein the step of defining the rolling element is implemented in an atmosphere which is filled with the inert gas for filling in the rolling element arranging space.

8. A method for manufacturing the hub unit according to claim 4, comprising a step of defining the rolling element arranging space by assembling together the outer ring member, the rolling elements, the hub wheel, the seal member and the cover, wherein the step of defining the rolling element is implemented in an atmosphere which is filled with the inert gas for filling the rolling element arranging space.

9. A method for manufacturing the hub unit according to claim 5, wherein the inert gas is filled in the rolling element arranging space by filling the inert gas from the gas filling hole formed in the outer ring member and the gas filling hole is then closed with the sealing material.

10. A method for transporting a hub unit, comprising: a step of transporting the hub unit according to claim 1 in a state that vibrations are applied to the hub unit,wherein the hub unit is assembled on to a vehicle in a state that the inert gas is filled in the rolling element arranging space.