Patent ID: 12234912

DESCRIPTION OF EMBODIMENTS

Hereinafter, a bearing device for a vehicle wheel1as a first embodiment of a bearing device for a vehicle wheel will be described with reference toFIGS.1and2. Note that in the following description, an inner side represents the vehicle body side of the bearing device for a vehicle wheel1when attached to the vehicle body, and an outer side represents the vehicle wheel side of the bearing device for a vehicle wheel1when attached to the vehicle body.

As illustrated inFIG.1, the bearing device for a vehicle wheel1rotatably supports a vehicle wheel in a suspension device of a vehicle such as an automobile. The bearing device for a vehicle wheel1includes an outer ring2, a hub ring3, an inner ring4, rolling elements5, an inner-side seal member6, and an outer-side seal member7.

As illustrated inFIG.1, the outer ring2, which is an outer member, supports the hub ring3and the inner ring4. An inner-side opening2binto which the inner-side seal member6can be fitted is formed in an inner-side end portion of the outer ring2. An outer-side opening2cinto which the outer-side seal member7can be fitted is formed in an outer-side end portion2fof the outer ring2. A vehicle body mounting flange2dfor being mounted to a knuckle of the suspension device, not illustrated, is integrally provided on an outer peripheral surface2eof the outer ring2. On the inner side and the outer side of the inner peripheral surface of the outer ring2, a plurality of rows of inner raceway surfaces2a,2aare provided in the circumferential direction.

The inner member includes the hub ring3and the inner ring4. The hub ring3rotatably supports the vehicle wheel of the vehicle, not illustrated. A small-diameter step portion3awhose diameter is reduced is provided on the outer peripheral surface of an inner-side end portion of the hub ring3. A vehicle wheel mounting flange3bfor mounting the vehicle wheel is integrally provided at an outer-side end portion of the hub ring3. A hub bolt3cfor fastening the hub ring3and a vehicle wheel or a brake device is press-fitted into the vehicle wheel mounting flange3b. An inner raceway surface3dis provided on the outer side on the outer peripheral surface of the hub ring3. A shoulder portion3e, a curved surface portion3f, and a flat surface portion3g, which are portions where the outer-side seal member7is disposed, are continuously provided on the outer side with respect to the inner raceway surface3don the outer peripheral surface (seeFIG.2and the like). The flat surface portion3gis located at the base end portion of the vehicle wheel mounting flange3b.

The inner ring4is press-fitted to the small-diameter step portion3aof the hub ring3. An inner raceway surface4ais provided on the outer peripheral surface of the inner ring4. That is, the inner ring4forms the inner raceway surface4aon the inner side of the hub ring3.

The rolling elements5include a plurality of balls and cages that hold the balls, respectively.

The inner-side seal member6includes a substantially cylindrical seal plate6aand a substantially cylindrical slinger6b. The seal plate6ais fitted to the inner-side opening2bof the outer ring2, and the slinger6bis fitted to the inner ring4.

As illustrated inFIGS.1and2, the outer-side seal member7closes the outer-side opening end of the annular space formed by the outer ring2and the hub ring3. The outer-side seal member7includes a core metal8, a metal ring9, a seal member10, and a sealing material20.

The core metal8is formed by, for example, pressing a steel plate. As illustrated inFIG.2, the core metal8includes a cylindrical portion8aand a bent portion8b.

The cylindrical portion8ais fitted into the outer-side opening2cof the outer ring2(the inner peripheral surface of the outer-side end portion2fof the outer ring2). The bent portion8bis bent from the outer-side end portion of the cylindrical portion8aand extends radially inward.

The seal member10made of, for example, synthetic rubber is joined (here, vulcanized-bonded) to the core metal8. A radial lip10a, an inner axial lip10b, and an outer axial lip10cof the seal member10are joined to the bent portion8b. The radial lip10ais provided on the radially innermost side of the bent portion8b. The radial lip10aprevents grease inside the bearing device for a vehicle wheel1from leaking to the outside. The inner axial lip10bis provided radially outside the radial lip10a. The outer axial lip10cis provided radially outside the inner axial lip10b.

The metal ring9is formed by, for example, pressing a steel plate. The metal ring9includes a cylindrical portion9a, a curved portion9b, a disk portion9c, a tapered portion9d, and a flange portion9e.

The cylindrical portion9ais fitted to the shoulder portion3e(portion adjacent to the inner peripheral raceway surface3don the outer side) of the hub ring3. The radial lip10ais in sliding contact with the cylindrical portion9avia a grease oil film. The curved portion9bhas a substantially arc shape in a cross-sectional view, and increases in diameter radially outward from the outer-side end portion of the cylindrical portion9atoward the outer side. The inner axial lip10bis in sliding contact with the curved portion9bvia the grease oil film. The disk portion9cextends radially outward from a front end portion of the curved portion9b. The outer axial lip10cis in sliding contact with the disk portion9cvia the grease oil film. The disk portion9cfaces the flat surface portion3gof the hub ring3. Note that the curved portion9bis a portion between a portion of the metal ring9fitted to the hub ring3and a portion of the metal ring9facing the vehicle wheel mounting flange3b.

The curved portion9bof the metal ring9is provided to improve rigidity of the metal ring9. By providing the curved portion9b, rigidity of the metal ring9can be improved, and movement of the metal ring9when a turning load of the vehicle is applied can be suppressed.

The tapered portion9dincreases in diameter from the outer peripheral edge of the disk portion9ctoward the inner side. The flange portion9eextends radially outward from the front end portion of the tapered portion9d.

The hub ring3has the curved surface portion3fwhich faces the curved portion9bof the metal ring9and is an outer peripheral surface having a substantially arc shape in a cross-sectional view. The curved surface portion3fis formed over the entire circumference of the hub ring3. The curved surface portion3fincreases in diameter radially outward from the outer-side end of the shoulder portion3eof the hub ring3toward the outer side. An annular space S having a substantially crescent shape in a cross-sectional view is provided between the curved portion9band the curved surface portion3fThe annular space S is filled with the sealing material20, which is an example of a filler. The sealing material20is a material that is applied to a space (gap) portion of a structure to exhibit functions such as waterproofness and airtightness. The sealing material20of the present embodiment is held in a gel state (paste state). That is, the sealing material20of the present embodiment is not cured. The sealing material20has predetermined viscosity. As the sealing material20, there are various choices from an acrylic-based sealing material, a urethane-based sealing material, a polyurethane-based sealing material, a silicon-based sealing material, a modified silicon sealing material, an oily coking-based sealing material, a polysulfide-based sealing material, a butyl rubber-based sealing material, and the like.

As a method of filling the annular space S with the sealing material20, for example, before the outer-side seal member7is assembled to the hub ring3, the sealing material20is applied annularly along the circumferential direction of the annular curved surface portion3fof the hub ring3by using a coating device, and the outer-side seal member7is assembled to the hub ring3to which the sealing material20is applied, and therefore the applied sealing material20spreads and is filled in the annular space S. Thus, the annular space S is sealed by the sealing material20.

In addition, with respect to the filling amount of the sealing material20into the annular space S, the upper limit value is an amount of filling 100% of the volume of the annular space S, that is, the space volume between the hub ring3(curved surface portion3f) and the metal ring9(curved portion9b) with the sealing material20(amount that does not protrude to the outside of the annular space S), and the lower limit value is an amount by which the sealing material20is uniformly applied at least to the fitting portion between the hub ring3and the metal ring9without any gap. Within such a filling amount range, the sealing material20can exhibit functions such as waterproofness and airtightness.

According to the configuration described above, the annular space S is provided between the curved portion9bof the metal ring9and the curved surface portion3fof the hub ring3, and the sealing material20is filled in the annular space S. As a result, it is possible to prevent foreign matter such as muddy water from penetrating into the interior of the bearing through the annular space S and to improve muddy water resistance. That is, since a conventional bearing device for a vehicle wheel has an annular space S as illustrated inFIG.5, there is a possibility that foreign matter such as muddy water accumulates in the annular space S and the foreign matter such as muddy water intrudes into the interior of a bearing. In contrast, in the bearing device for a vehicle wheel1of the present embodiment, since the annular space S is sealed by the sealing material20, it is possible to suppress accumulation of foreign matter such as muddy water in the annular space S and to prevent the foreign matter such as muddy water from penetrating into the interior of the bearing. That is, the sealing material20functions to close the annular space S, which is one of the paths through which foreign matter such as muddy water enters. In addition, since the sealing material20of the present embodiment is held in a gel state (paste state) without being cured, degradation over time such as cracking due to curing is suppressed.

The outer-side seal member7of the bearing device for a vehicle wheel1is not provided with a rubber member unlike the conventional bearing device for a vehicle wheel illustrated inFIG.5. Therefore, in the bearing device for a vehicle wheel1, it is not necessary to provide a region for arranging a rubber member in the flat surface portion3gthat is the surface in contact with the metal ring9(disk portion9c) in the hub ring3, and the outer-side seal member can be downsized.

In addition, since the outer-side seal member7of the bearing device for a vehicle wheel1is not provided with a rubber member, there is an advantage that no design restriction is imposed even in a case where the outer-side seal member and a peripheral component such as a head portion of a hub bolt are close to each other. Furthermore, since the outer-side seal member7of the bearing device for a vehicle wheel1is not provided with a rubber member, the cost can be reduced.

Next, a second embodiment and a third embodiment will be described as modifications of the bearing device for a vehicle wheel according to the present invention with reference to the drawings. In the following description of each embodiment, portions added or changed in each embodiment will be mainly described, and the same components and the same portions or components and portions having similar functions will be denoted by the same reference numerals, and description thereof will be omitted.

Second Embodiment

Next, a bearing device for a vehicle wheel1A as the second embodiment of the bearing device for a vehicle wheel according to the present invention will be described with reference toFIG.3. The bearing device for a vehicle wheel1A according to the present embodiment is a modification of the first embodiment, and a rubber member11is added to the outer-side seal member7of the bearing device for a vehicle wheel1according to the first embodiment.

The rubber member11is joined (here, vulcanized-bonded) to surfaces of a disk portion9c, a tapered portion9d, and a flange portion9ewhich face a flat surface portion3gof a hub ring3in the axial direction. The rubber member11is, for example, synthetic rubber. The rubber member11is provided radially outside a metal ring9and is in contact with the flat surface portion3gof the hub ring3.

As a result, the bearing device for a vehicle wheel1A has the effect similar to that of the bearing device for a vehicle wheel1of the first embodiment, and since the rubber member11is provided, it is possible to further suppress foreign matter such as muddy water from penetrating into the interior of a bearing.

Third Embodiment

Next, a bearing device for a vehicle wheel1B as the third embodiment of the bearing device for a vehicle wheel according to the present invention will be described with reference toFIG.4. The bearing device for a vehicle wheel1B according to the present embodiment is a modification of the first embodiment, and includes a folded portion9b1in lieu of the curved portion9bin the bearing device for a vehicle wheel1according to the first embodiment. The folded portion9b1has a linear shape in a cross-sectional view, and increases in diameter radially outward from the outer-side end portion of a cylindrical portion9atoward the outer side. The folded portion9b1is a portion between a portion of a metal ring9fitted to a hub ring3and a portion of the metal ring9facing a vehicle wheel mounting flange3b. An annular space S1having a substantially semi-elliptical shape in a cross-sectional view is provided between the folded portion9b1and a curved surface portion3fThe annular space S1is filled with a sealing material20.

Thus, the bearing device for a vehicle wheel1B has the effect similar to that of the bearing device for a vehicle wheel1of the first embodiment. In addition, in a case where the folded portion9b1is formed linearly, the annular space S1becomes larger; however, the annular space S1can be easily sealed by filling the annular space S1with the sealing material20, which is a filler. As a result, muddy water resistance is further improved.

Note that a rubber member11may be added to the bearing device for a vehicle wheel1B as in the bearing device for a vehicle wheel1A of the second embodiment.

As described above, each of the bearing devices for a vehicle wheel1,1A, and1B according to the present embodiments has been described as a bearing device for a vehicle wheel having a third-generation structure in which the inner raceway surface3dof the rolling elements5is directly formed on the outer periphery of the hub ring3. However, each of the bearing devices for a vehicle wheel1,1A, and1B is not limited to this, and for example, may have a second-generation structure of inner ring rotation in which a pair of inner rings4is press-fitted and fixed to the hub ring3. In addition, the above-described embodiments are merely representative forms of the present invention, and various modifications can be made without departing from the gist of the present invention.

INDUSTRIAL APPLICABILITY

The present invention is applicable to a bearing device for a vehicle wheel.

REFERENCE SIGNS LIST

1bearing device for a vehicle wheel2outer ring2aouter raceway surface2eouter peripheral surface2fouter-side end portion3hub ring3asmall-diameter step portion3bvehicle wheel mounting flange4inner ring4ainner raceway surface5rolling element7outer-side seal member8core metal9metal ring10seal member20sealing materialS annular space