Sealing device and wheel bearing device provided with sealing device

Abstract

Provided are: a sealing device capable of maintaining sealability between an end face on one side in an axial direction of an outer ring and a standing plate part even when a core metal falls to one side in the axial direction which is a direction of separation from the end face on the one side in the axial direction of the outer ring; and a wheel bearing device provided with the sealing device. The present invention includes a core metal 11 fitted to an inner periphery of an outer ring 2, and a seal member 12 joined to the core metal 11. The core metal 11 has an inner fitting part 11a fitted to the inner periphery of the outer ring 2, and a standing plate part 11b extending from one end part in an axial direction of the inner fitting part 11a to an outer diameter side. The seal member 12 has a projection part 12f protruding from the standing plate part 11b toward an inner side, and the standing plate part 11b falls to the other side in the axial direction in a direction orthogonal to a rotation axis center X.

Description

Sealing device and wheel bearing device including the same

[0001] The present invention relates to a technique of a sealing device and a wheel bearing device including the sealing device.

[0002] Conventionally, a wheel bearing device that rotatably supports a wheel in a suspension device of an automobile or the like is known. The wheel bearing device is provided with a sealing device that closes an opening end of an annular space formed by an outer member and an inner member to prevent foreign matters such as mud and water from entering.

[0003] For example, the sealing device of the wheel bearing device disclosed in Patent Document 1 includes a slinger fitted to a hub ring which is an inner member, a core metal fitted to the inner circumference of an outer ring which is an outer member, and a seal member integrally joined to the core metal.

[0004] The core metal is made of, for example, a steel plate, and has a cylindrical fitting portion fitted to the inner circumference of an axial-direction one-side end opening portion of the outer ring which is an outer member, an inner portion extending from the other axial-direction end portion of the fitting portion toward the inner diameter side, and a standing plate portion extending from the one axial-direction end portion of the fitting portion toward the outer diameter side. The seal member is formed of an elastic member such as synthetic rubber, for example, and is joined to the core metal by vulcanization adhesion.

[0005] When the core metal joined with the seal member is press-fitted and fitted into the outer member, the core metal may be deformed due to the influence of the press-fitting and the machining accuracy of the core metal. In particular, the standing plate portion of the core metal may fall down to one side or the other side in the axial direction. When the core metal falls down to the other side in the axial direction, which is the direction in which the core metal abuts against the axial-direction one-side end face of the outer ring, the deformation can be suppressed by the close contact between the axial-direction one-side end face of the outer ring and the standing plate portion. However, when the core metal falls down to the one side in the axial direction, which is the direction in which the core metal is separated from the axial-direction one-side end face of the outer ring, there is a concern that a gap may occur between the axial-direction one-side end face of the outer ring and the standing plate portion.

[0006] Furthermore, a projection may be provided on the other side of the sealing member that is joined to the other axial end face of the vertical plate portion to improve sealing performance. When the core metal tilts in the axial direction, away from the axial end face of the outer ring, a gap is created between the axial end face of the outer ring and the vertical plate portion, making it difficult to control the amount of compression of the projection. As a result, the sealing performance between the axial end face of the outer ring and the vertical plate portion cannot be maintained, and there was a possibility that muddy water could enter the inside of the bearing.

[0007] Japanese Patent Publication No. 2018-71714

[0008] Therefore, the present invention has been made in view of the above circumstances, and aims to provide a sealing device and a wheel bearing device equipped with the sealing device that can maintain airtightness between the axial end face of the outer ring and the upright plate portion, even when the core metal tilts in the axial direction toward the axial side, which is the direction away from the axial end face of the outer ring.

[0009] That is, a sealing device for sealing an annular space formed between an outer member and an inner member of a wheel bearing device, comprising a core metal fitted to the inner circumference of the outer member and a sealing member joined to the core metal, wherein the core metal has an inner fitting portion fitted to the inner circumference of the outer member and a vertical plate portion extending outward from one axial end of the inner fitting portion, the sealing member has a projection protruding from the vertical plate portion toward the other axial side, and the vertical plate portion is tilted toward the other axial side with respect to a direction perpendicular to the axial direction.

[0010] The present invention provides the following effects. Specifically, according to the wheel bearing device of the present invention, even when the core metal tilts in the axial direction toward the axial side, which is the direction away from the axial end face of the outer ring, the airtightness between the axial end face of the outer ring and the upright plate can be maintained.

[0011] A partial cross-sectional view showing a wheel bearing device according to the first embodiment of the present invention. An enlarged partial cross-sectional view showing the hub ring, outer side seal member, and outer ring. An enlarged cross-sectional view showing the outer side seal member. An enlarged cross-sectional view showing the hub ring, outer side seal member, and outer ring. An enlarged cross-sectional view showing the outer side end face of the outer side seal member and outer ring. An enlarged cross-sectional view showing the hub ring, outer side seal member, and outer ring. An enlarged cross-sectional view showing the outer side end face of the outer side seal member and outer ring. An enlarged cross-sectional view showing the outer side seal member according to the second embodiment of the present invention.

[0012] The embodiments for carrying out the present invention will be described below with reference to the attached drawings.

[0013] [First Embodiment of Wheel Bearing Device] The wheel bearing device 1 shown in Figure 1 is a first embodiment of the wheel bearing device according to the present invention, and is used to rotatably support a wheel in the suspension system of a vehicle such as an automobile.

[0014] In the following explanation, "axial direction" refers to the direction along the rotation axis X of the wheel bearing device 1. Furthermore, "outer side" refers to one side in the axial direction, which is the wheel side of the wheel bearing device 1 when it is mounted on the vehicle body, and "inner side" refers to the other side in the axial direction, which is the vehicle body side of the wheel bearing device 1 when it is mounted on the vehicle body.

[0015] The wheel bearing device 1 has a configuration referred to as the third generation, and comprises an outer ring 2 which is an outer member, a hub ring 3 and an inner ring 4 which are inner members, two rows of inner ball rows 5 and outer ball rows 6 which are rolling rows, and an inner sealing member 9 and an outer sealing member 10 which are sealing devices.

[0016] An inner side opening 2a is formed at the inner end of the outer ring 2, into which an inner side sealing member 9 can be fitted. An outer side opening 2b is formed at the outer end face 2f of the outer ring 2, into which an outer side sealing member 10 can be fitted. An inner side outer raceway surface 2c and an outer side outer raceway surface 2d are formed on the inner circumferential surface of the outer ring 2. A vehicle body mounting flange 2e for attaching the outer ring 2 to the vehicle body side member is integrally formed on the outer circumferential surface of the outer ring 2.

[0017] A small-diameter stepped portion 3a, which is smaller in diameter than the outer end, is formed on the inner end of the outer circumferential surface 3j of the hub wheel 3. A wheel mounting flange 3b for attaching a wheel is integrally formed on the outer end of the hub wheel 3. Multiple bolt holes 3f are formed in the wheel mounting flange 3b. Hub bolts for fastening the hub wheel 3 to a wheel or brake component can be press-fitted into the bolt holes 3f.

[0018] The outer circumferential surface 3j of the hub ring 3 is provided with an inner raceway surface 3c on the outer side, facing the outer raceway surface 2d of the outer ring 2. In other words, the inner raceway surface 3c is formed on the outer side of the inner member by the hub ring 3. The outer side seal member 10 is fitted into the outer side opening end of the annular space S formed by the outer ring 2 and the hub ring 3, and closes the outer side opening end. The outer side seal member 10 is an example of a sealing device.

[0019] An inner ring 4 is provided on the small-diameter stepped portion 3a of the hub wheel 3. The inner ring 4 is fixed to the small-diameter stepped portion 3a of the hub wheel 3 by press-fitting. The inner ring 4 applies preload to the rolling rows, which consist of the inner ball row 5 and the outer ball row 6.

[0020] The outer circumferential surface of the inner ring 4 is provided with an inner raceway surface 4a that faces the outer raceway surface 2c on the inner side of the outer ring 2. In other words, the inner raceway surface 4a is formed on the inner side of the inner member by the inner ring 4.

[0021] The inner ball row 5 and the outer ball row 6, which are rolling elements, are composed of multiple balls 7, which are rolling elements, held by a retainer 8. The inner ball row 5 is rotatably sandwiched between the inner raceway surface 4a of the inner ring 4 and the inner outer raceway surface 2c of the outer ring 2. The outer ball row 6 is rotatably sandwiched between the inner raceway surface 3c of the hub ring 3 and the outer outer raceway surface 2d of the outer ring 2. In other words, the inner ball row 5 and the outer ball row 6 are rotatably housed between the raceway surfaces of the outer and inner members.

[0022] In the wheel bearing device 1, a double-row angular contact ball bearing is constructed from an outer ring 2, a hub ring 3 and an inner ring 4, an inner ball row 5, and an outer ball row 6. Alternatively, the wheel bearing device 1 may be configured with a double-row tapered roller bearing instead of the double-row angular contact ball bearing.

[0023] [Outer side sealing member] As shown in Figures 2 to 7, the outer side sealing member 10, which is a sealing device, comprises a core metal 11 fitted to the inner circumference of the outer side of the outer ring 2, and a sealing member 12 integrally joined to the core metal 11.

[0024] The core metal 11 is made of, for example, a steel plate and has an inner fitting portion 11a that fits onto the inner circumference of the outer opening 2b of the outer ring 2, a vertical plate portion 11b that extends outward from the outer end of the inner fitting portion 11a, and an inner portion 11c that extends inward from the inner end of the inner fitting portion 11a.

[0025] The inner fitting portion 11a is a cylindrical part that extends in the axial direction, and its outer circumference abuts against the inner circumference of the outer ring 2 for fitting. The vertical plate portion 11b is bent from the outer end of the inner fitting portion 11a and extends outwards. A portion of the outer diameter side of the vertical plate portion 11b has a thinner plate thickness. The inner portion 11c is bent from the inner end of the inner fitting portion 11a, extends outwards and inwards, and then extends inwards.

[0026] As shown in Figure 3, the vertical plate portion 11b is tilted inward with respect to the direction perpendicular to the rotation axis X. The tilt angle θ1 of the vertical plate portion 11b from the direction perpendicular to the rotation axis X is formed to be 3.5° or less, preferably 2.5° to 3.5°.

[0027] As shown in Figure 4, when the outer sealing member 10 is fitted into the outer opening of the annular space S formed by the outer ring 2 and the hub ring 3, the inner fitting portion 11a moves inward while contacting the inner circumferential surface of the outer ring 2. At this time, the outer end face 2f of the outer ring 2 and the upright plate portion 11b of the core metal 11 come into contact. If the upright plate portion 11b is tilted outward with respect to the direction perpendicular to the rotation axis X, a gap is created between the sealing member 12 and the outer end face 2f, and sealing cannot be ensured. As a result, the sealing between the outer end face 2f of the outer ring 2 and the upright plate portion 11b cannot be maintained, and there was a possibility that muddy water could enter the annular space S formed by the outer ring 2 and the hub ring 3.

[0028] In this embodiment, the vertical plate portion 11b is tilted inward with respect to the direction perpendicular to the rotation axis X, so that the vertical plate portion 11b reliably contacts the outer end face 2f, thereby improving the sealing performance.

[0029] The sealing member 12 is formed of an elastic material such as synthetic rubber and is joined to the core metal 11 by vulcanization bonding. As shown in Figures 2 and 3, the sealing member 12 has a base portion 12a, a radial lip 12b, a plurality of side lips 12c, a weir portion 12d, an inner side portion 12e, a projection portion 12f, and a recess portion 12g. The base portion 12a is joined to the core metal 11 from the inner portion 11c through the inner fitting portion 11a to the vertical plate portion 11b.

[0030] The radial lip 12b is located at the inner diameter end of the sealing member 12 and extends inward from the inner portion 11c of the core metal 11. The radial lip 12b slides against the outer surface of the hub wheel 3 and the wheel mounting flange 3b via a grease oil film.

[0031] In this embodiment, the radial lip 12b is in sliding contact with the outer surface of the hub wheel 3 and the wheel mounting flange 3b via a grease oil film. However, it is not limited to this configuration. For example, a slinger may be fitted to the base of the wheel mounting flange 3b on the outer surface of the hub wheel 3, and the radial lip 12b may be in sliding contact with the outer surface of the slinger.

[0032] Multiple side lips 12c are formed, and they extend from the inner portion 11c of the core metal 11 toward the wheel mounting flange 3b and toward the outer diameter, on the outer diameter side of the radial lip 12b. The side lips 12c slide against the outer circumferential surface of the hub wheel 3 via a grease oil film.

[0033] The weir portion 12d covers the vertical plate portion 11b of the core metal 11 and protrudes outward from the outer peripheral surface 2h of the outer ring 2.

[0034] The inner side portion 12e is the inner side portion of the vertical plate portion 11b and is joined to the portion where the plate thickness has decreased. The inner side portion 12e is provided along the vertical plate portion 11b, and its inner diameter side end is formed to be continuous with the inner side end face of the vertical plate portion 11b. That is, it is formed so that the thickness of the vertical plate portion 11b, the sum of the thickness of the thinned portion of the vertical plate portion 11b and the inner side portion 12e are the same.

[0035] The projection 12f is an annular portion that protrudes inward from the inner side surface 12e. As shown in Figures 2 and 4, when the sealing member 12 is fitted onto the outer ring 2, the projection 12f is in contact with the outer end face 2f of the outer ring 2.

[0036] The recess 12g is a portion formed around the projection 12f. The recess 12g is formed by recessing from the surface of the inner side portion 12e toward the outer side.

[0037] As shown in Figure 5, the projection 12f has an axial height C from the surface of the inner side portion 12e. The surface of the inner side portion 12e is the part of the inner side portion 12e that is exposed on the innermost side, and in this embodiment, it is the straight portion of the inner side portion 12e.

[0038] Furthermore, as shown in Figure 5, the recess 12g has an axial depth D from the surface of the inner side portion 12e. The axial height C of the projection 12f and the axial depth D of the recess 12g have the following relationship: 0.2 × C ≤ D ≤ 0.3 × C

[0039] With this configuration, the entire amount of compression of the projection 12f is transferred to the recess 12g. That is, when the projection 12f elastically deforms upon contact with the outer end face 2f of the outer ring 2, it is housed in the space within the surrounding recess 12g. As a result, a gap is less likely to form between the projection 12f and the outer end face 2f, improving the sealing performance between the outer end face 2f of the outer ring 2 and the sealing member 12. Furthermore, since the vertical plate portion 11b is tilted inward with respect to the direction perpendicular to the rotation axis X, the projection 12f is reliably in contact with the outer end face 2f, making it easier to manage the amount of compression. As a result, the sealing performance of the outer sealing member 10 is easily improved.

[0040] Furthermore, as shown in Figures 4 and 7, the outer end face 2f of the outer ring 2 has a radial length A between the inner diameter end and the outer diameter end. The outer diameter end is the outer diameter end of the outer ring 2 and the point of intersection with the portion that slopes toward the inner side. The inner diameter end is the end of the outer ring 2 and the point of intersection with the portion that curves toward the inner side. As a result, the portion between the inner diameter end and the outer diameter end is formed by a plane perpendicular to the direction along the rotation axis X.

[0041] The radial length P between the outer diameter end of the outer end face 2f of the outer ring 2 and the contact position of the projection 12f with the outer end face 2f has the following relationship with the radial length A between the inner diameter end and the outer diameter end: 0.2 × A ≤ P ≤ 0.3 × A

[0042] By configuring it in this way, the projection 12f is located on the outer diameter side of the outer end face 2f of the outer ring 2, thereby improving the sealing performance.

[0043] Further, as shown in FIG. 6, the outer ring 2 has an axial length B between the outer end face 2f and the outer end of the outer ball row 6. Here, the outer end of the outer ball row 6 is the point located on the outermost side of the balls constituting the outer ball row 6, and in the present embodiment, it is located on the inner side of the outer end portion of the inner raceway surface 3c of the hub ring 3. Further, the shaft core 11 has a fitting length L of the fitting portion 11a in the axial direction with respect to the outer ring 2. The fitting length L has the following relationship with the axial length B. L≧0.4×B Here, the fitting length L is the length from the outer end face 2f to the innermost position where the shaft core 11 is fitted.

[0044] That is, the fitting length L of the shaft core 11 is 40% or more of the axial length B between the outer end face 2f and the outer end of the outer ball row 6. By sufficiently taking the length of the fitting portion 11a of the shaft core 11, the contact area of the fitting surface increases and the sealing performance improves.

[0045] [Second Embodiment of Wheel Bearing Device] The wheel bearing device 1 according to the first embodiment can also be configured like the wheel bearing device 1 according to the second embodiment.

[0046] As shown in FIG. 8, the wheel bearing device 1 according to the second embodiment is different from the wheel bearing device 1 according to the first embodiment in the configuration of the upright plate portion 11b of the shaft core 11 of the outer seal member 10 and the inner side surface portion 12e of the seal member 12. Note that members denoted by the same reference numerals as those in the first embodiment are the same as those in the first embodiment, and thus the description thereof is omitted.

[0047] As shown in FIG. 8, the upright plate portion 11b is erected parallel to the direction orthogonal to the rotation axis X. Further, a part of the outer diameter side portion of the upright plate portion 11b has a reduced plate thickness.

[0048] Further, the inner side surface portion 12e of the seal member 12 is an inner side surface portion of the upright plate portion 11b, and is joined to a portion where the plate thickness is reduced. The inner side surface portion 12e is formed such that the inner diameter side end portion is continuous with the inner side end surface of the upright plate portion 11b. Further, the inner side surface portion 12e of the seal member 12 is formed such that the thickness increases toward the inner side as it goes toward the outer diameter side. That is, the倒伏 angle θ2 of the surface of the inner side surface portion 12e from the direction orthogonal to the rotation axis X of the upright plate portion is 3.5° or less, preferably 2.5° to 3.5°.

[0049] When the outer side seal member 10 is fitted to the outer side opening end of the annular space S formed by the outer ring 2 and the hub ring 3, the inner fitting portion 11a moves toward the inner side while contacting the inner peripheral surface of the outer ring 2. At this time, the outer side end surface 2f of the outer ring 2 and the inner side surface portion 12e of the seal member 12 come into contact with each other. Since the inner side surface portion 12e is inclined toward the inner side with respect to the direction orthogonal to the rotation axis X, the inner side surface portion 12e surely comes into contact with the outer side end surface 2f, and the sealing performance is improved. Further, since the seal member 12 is formed of an elastic member, when the inner side surface portion 12e comes into contact with the outer side end surface 2f, the inner side surface portion 12e also comes into contact while elastically deforming together with the protruding portion 12f. Thereby, the sealing performance is further improved.

[0050] As described above, an outer side seal member 10 which is a sealing device for sealing the annular space S formed between the outer ring 2 which is an outer member of the wheel bearing device 1, the hub ring 3 which is an inner member, and the inner ring 4, includes a metal core 11 fitted to the inner periphery of the outer ring 2, and a seal member 12 joined to the metal core 11. The metal core 11 has an inner fitting portion 11a fitted to the inner periphery of the outer ring 2, and an upright plate portion 11b extending from one axial end portion of the inner fitting portion 11a toward the outer diameter side. The seal member 12 has a protruding portion 12f protruding from the upright plate portion 11b toward the inner side. The upright plate portion 11b is inclined toward the other axial side with respect to the direction orthogonal to the rotation axis X. By configuring like this, since the upright plate portion 11b is inclined toward the inner side with respect to the direction orthogonal to the rotation axis X, the upright plate portion 11b surely comes into contact with the outer side end surface 2f, and the sealing performance is improved.

[0051] Furthermore, the sealing member 12 has an inner side surface portion 12e joined to the inner side surface of the vertical plate portion 11b, a projection portion 12f projecting axially from the inner side surface portion 12e to the other side, and a recess 12g formed around the projection portion 12f and recessed outward from the surface of the inner side surface portion 12e. The axial height C of the projection portion 12f from the surface of the inner side surface portion 12e and the axial depth D of the recess 12g from the surface of the inner side surface portion 12e have the relationship 0.2 × C ≤ D ≤ 0.3 × C. With this configuration, the crushing allowance of the projection portion 12f is entirely transferred to the recess 12g, improving the sealing performance between the outer end face 2f of the outer ring 2 and the sealing member 12.

[0052] Furthermore, the wheel bearing device 1 comprises an outer ring 2 having double rows of outer raceway surfaces 2c and 2d on its inner circumference, an inner member composed of a hub ring 3 and an inner ring 4 having double rows of inner raceway surfaces 3c and 4a facing the double rows of outer raceway surfaces 2c and 2d, double rows of rolling elements, which are balls 7, rotatably housed between the raceway surfaces of the outer ring 2 and the hub ring 3 and inner ring 4, and an outer side seal member 10 which is a sealing device, wherein the outer ring 2 has an outer side end face 2f perpendicular to the rotation axis X and facing the outer side, the outer side end face 2f has a radial length A between the inner diameter side end and the outer diameter side end of the outer side end face 2f, the projection 12f of the seal member 12 is in contact with the outer side end face 2f of the outer ring, and the radial length P between the outer diameter side end of the outer side end face 2f and the contact position of the projection 12f with respect to the outer side end face 2f and the radial length A is, The relationship 0.2 × A ≤ P ≤ 0.3 × A is satisfied. By configuring it in this way, the projection 12f is located on the outer diameter side of the outer end face 2f of the outer ring 2, thereby improving the sealing performance.

[0053] Furthermore, the axial length B between the outer end face 2f of the outer ring and the outer end of the outer ball row 6, and the axial fitting length L of the inner fitting portion 11a with respect to the outer ring 2, have the relationship L ≥ 0.4 × B. With this configuration, the fitting length L of the core metal 11 is 40% or more of the axial length B between the outer end face 2f and the outer end of the outer ball row 6, and by making the length of the inner fitting portion 11a of the core metal 11 sufficient, the contact area of ​​the fitting surface is increased and the sealing performance is improved.

[0054] Although embodiments of the present invention have been described above, the present invention is not limited in any way to these embodiments, but is merely illustrative. It can be implemented in various other forms without departing from the spirit of the invention, and the scope of the present invention is indicated by the claims, and further includes all modifications within the meaning and scope of equivalents as described in the claims.

[0055] The present invention can be used in sealing devices and wheel bearing devices equipped with sealing devices.

[0056] 1. Wheel bearing device 2. Outer ring (outer member) 3. Hub ring 4. Inner ring 5. Inner ball row 6. Outer ball row 7. Balls (rolling elements) 8. Cage 10. Outer sealing member 11. Core metal 12. Seal member

Claims

1. A sealing device for sealing an annular space formed between an outer member and an inner member of a wheel bearing device, comprising: a core metal fitted to the inner circumference of the outer member; and a sealing member joined to the core metal, wherein the core metal has an inner fitting portion fitted to the inner circumference of the outer member and a vertical plate portion extending outward from one axial end of the inner fitting portion; the sealing member has a projection protruding axially from the vertical plate portion toward the other axial side; and the vertical plate portion is tilted axially toward the other side with respect to a direction perpendicular to the axial direction.

2. The sealing device according to claim 1, wherein the sealing member has an other side portion joined to the other side of the vertical plate portion in the axial direction, a projection protruding from the other side portion in the axial direction, and a recess formed around the projection and recessed in one direction from the surface of the other side portion in the axial direction, and the axial height C of the projection from the surface of the other side portion and the axial depth D of the recess from the surface of the other side portion in the axial direction are in relation to 0.2 × C ≤ D ≤ 0.3 × C.

3. A wheel bearing device comprising: an outer member having double rows of outer raceway surfaces on its inner circumference; an inner member having double rows of inner raceway surfaces facing the double rows of outer raceway surfaces; double rows of rolling elements rotatably housed between the raceway surfaces of the outer member and the inner member; and the sealing device according to claim 1 or claim 2, wherein the outer member has an axial end face perpendicular to the axial direction, the axial end face has a radial length A between the inner diameter side end and the outer diameter side end of the axial end face, the projection of the sealing member is in contact with the axial end face of the outer member, and the radial length P between the outer diameter side end of the axial end face and the contact position of the projection with respect to the axial end face and the radial length A are related by 0.2 × A ≤ P ≤ 0.3 × A.

4. The wheel bearing device according to claim 3, wherein the axial length B between the axial end face of the outer member and the axial end of the rolling element on the axial side, and the fitting length L of the inner fitting portion with respect to the outer member in the axial direction, are related such that L ≥ 0.4 × B.

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