Sealing device and wheel bearing device equipped with the sealing device

Abstract

The present invention provides 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 vertical plate portion, even when the core metal tilts axially to one side, which is the direction in which it moves away from the axial end face of the outer ring. [Solution] The device comprises a core metal 11 fitted to the inner circumference of the outer ring 2 and a sealing member 12 joined to the core metal 11. The core metal 11 has an inner fitting portion 11a fitted to the inner circumference of the outer ring 2 and a vertical plate portion 11b extending outward from one axial end of the inner fitting portion 11a. The sealing member 12 has a projection 12f protruding inward from the vertical plate portion 11b, and the vertical plate portion 11b is tilted axially to the other side with respect to the direction perpendicular to the rotation axis X.

Description

Technical Field

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

Background Art

[0002] Conventionally, a wheel bearing device that rotatably supports a wheel in a suspension device such as an automobile is known. The wheel bearing device is provided with a sealing device that closes the open 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 that is an inner member, a core metal fitted to the inner circumference of an outer ring that 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 the axial direction one-side end opening of the outer ring that is an outer member, an inner side portion extending from the axial direction other-side end portion of the fitting portion to the inner diameter side, and a standing plate portion extending from the axial direction one-side end portion of the fitting portion to 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 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. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2018-71714 [Overview of the Initiative] [Problems that the invention aims to solve]

[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. [Means for solving the problem]

[0009] That is, a sealing device for sealing an annular space formed between the outer member and the inner member of a wheel bearing device, The outer member comprises a core metal fitted to the inner circumference of the outer member and a sealing member joined to the core metal. The core metal has an inner fitting portion that fits onto the inner circumference of the outer member, and a vertical plate portion that extends outward from one axial end of the inner fitting portion. The sealing member has a projection that protrudes from the vertical plate portion toward the other side in the axial direction, The aforementioned vertical plate portion is tilted to the side opposite to the axial direction, with respect to the direction perpendicular to the axial direction. [Effects of the Invention]

[0010] The present invention provides the following effects: In other words, according to the wheel bearing device of the present invention, even when the core metal tilts 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. [Brief explanation of the drawing]

[0011] [Figure 1] A partial cross-sectional view showing a wheel bearing device according to the first embodiment of the present invention. [Figure 2] Similarly, an enlarged partial cross-sectional view showing the hub ring, outer side seal member, and outer ring. [Figure 3] This is an enlarged cross-sectional view showing the outer sealing member. [Figure 4] Similarly, an enlarged cross-sectional view showing the hub ring, outer seal member, and outer ring. [Figure 5] Similarly, an enlarged cross-sectional view showing the outer sealing member and the outer end face of the outer ring. [Figure 6] Similarly, an enlarged cross-sectional view showing the hub ring, outer seal member, and outer ring. [Figure 7] Similarly, an enlarged cross-sectional view showing the outer sealing member and the outer end face of the outer ring. [Figure 8] An enlarged cross-sectional view showing an outer sealing member according to a second embodiment of the present invention. [Modes for carrying out the invention]

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

[0013] [First Embodiment of a 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 description, the axial direction refers to the direction along the rotation axis X of the wheel bearing device 1. Also, the outer side refers to one side in the axial direction and represents the wheel side of the wheel bearing device 1 when attached to the vehicle body, and the inner side refers to the other side in the axial direction and represents the vehicle body side of the wheel bearing device 1 when attached to the vehicle body.

[0015] The wheel bearing device 1 has a configuration called the third generation, and includes an outer ring 2 as an outer member, a hub ring 3 and an inner ring 4 as inner members, two rows of inner side ball rows 5 and outer side ball rows 6 as rolling element rows, and inner side seal members 9 and outer side seal members 10 as sealing devices.

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

[0017] A small diameter step portion 3a having a diameter smaller than that of the outer side end is formed at the inner side end of the outer peripheral surface 3j of the hub ring 3. A wheel attachment flange 3b for attaching a wheel is integrally formed at the outer side end of the hub ring 3. A plurality of bolt holes 3f are formed in the wheel attachment flange 3b. A hub bolt for fastening the hub ring 3 to the wheel or brake components 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 to 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 cage 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 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 toward the outer diameter side. 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 toward the outer and inner diameter sides, and then extends toward the inner diameter side.

[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 to the outer opening end 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 circumferential surface of the hub wheel 3 and the wheel mounting flange 3b via a grease film. However, the embodiment is not limited to this, and for example, a slinger may be fitted to the base of the wheel mounting flange 3b on the outer circumferential surface of the hub wheel 3, and the radial lip 12b may be in sliding contact with the outer circumferential 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 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 is reduced. 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 reduced 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 from 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] Furthermore, as shown in Figure 6, the outer ring 2 has an axial length B between its 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 outermost point of the balls constituting the outer ball row 6, and in this embodiment, it is located on the inner side of the outer end of the inner raceway surface 3c of the hub ring 3. Furthermore, the core metal 11 has a fitting length L in the axial direction with respect to the outer ring 2 of the inner fitting portion 11a. The fitting length L has the following relationship with respect to the axial length B. L≧0.4×B Here, the fitting length L is defined as the length from the outer end face 2f to the innermost position where the core metal 11 is fitted.

[0044] In other words, 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.

[0045] [Second embodiment of a wheel bearing device] The wheel bearing device 1 according to the first embodiment can also be configured as the wheel bearing device 1 according to the second embodiment.

[0046] As shown in Figure 8, the wheel bearing device 1 according to the second embodiment differs from the wheel bearing device 1 according to the first embodiment in the configuration of the vertical plate portion 11b of the core metal 11 of the outer side seal member 10 and the inner side portion 12e of the seal member 12. Note that other components denoted by the same reference numerals as in the first embodiment have the same configuration as in the first embodiment and therefore their description is omitted.

[0047] As shown in Figure 8, the vertical plate portion 11b is erected parallel to the direction perpendicular to the rotation axis X. In addition, a portion of the outer diameter side of the vertical plate portion 11b has a thinner plate thickness.

[0048] Furthermore, the inner side portion 12e of the sealing member 12 is the inner side portion of the vertical plate portion 11b, and is joined to the portion where the plate thickness is reduced. The inner side portion 12e is formed so that its inner diameter end is continuous with the inner end face of the vertical plate portion 11b. In addition, the inner side portion 12e of the sealing member 12 is formed so that its thickness increases towards the inner side as it moves toward the outer diameter side. That is, the inclination angle θ2 of the surface of the inner side portion 12e from the direction perpendicular to the rotation axis X of the vertical plate portion is 3.5° or less, preferably 2.5° to 3.5°.

[0049] When the outer sealing member 10 is fitted into the outer opening end 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 inner side surface portion 12e of the sealing member 12 come into contact. Since the inner side surface portion 12e is tilted inward with respect to the direction perpendicular to the rotation axis X, the inner side surface portion 12e reliably comes into contact with the outer end face 2f, improving the sealing performance. Furthermore, since the sealing member 12 is made of an elastic material, when the inner side surface portion 12e comes into contact with the outer end face 2f, the inner side surface portion 12e also undergoes elastic deformation together with the projection portion 12f as it makes contact. This further improves the sealing performance.

[0050] As described above, the outer side seal member 10 is a sealing device for sealing the annular space S formed between the outer ring 2, which is the outer member of the wheel bearing device 1, and the hub ring 3 and inner ring 4, which are the inner members. The outer side seal member 10 comprises a core metal 11 fitted to the inner circumference of the outer ring 2, and a seal member 12 joined to the core metal 11. The core metal 11 has an inner fitting portion 11a fitted to the inner circumference of the outer ring 2, and a vertical plate portion 11b extending outward from one axial end of the inner fitting portion 11a. The seal member 12 has a projection 12f protruding inward from the vertical plate portion 11b, and the vertical plate portion 11b is tilted axially to the other side with respect to the direction perpendicular to the rotation axis X. With this configuration, the vertical plate portion 11b is tilted inward with respect to the direction perpendicular to the rotation axis X, ensuring that the vertical plate portion 11b makes reliable contact with the outer end face 2f, thereby improving sealing performance.

[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 portion 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 portion 12g from the surface of the inner side surface portion 12e are as follows: 0.2 × C ≤ D ≤ 0.3 × C They have a relationship. By configuring it in this way, the crushing allowance of the projection 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·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·4a facing the double rows of outer raceway surfaces 2c·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, 0.2 × A ≤ P ≤ 0.3 × A They have a relationship. 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 are, L≧0.4×B They have a relationship. 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. [Explanation of Symbols]

[0055] 1. Wheel bearing device 2. Outer ring (outer member) 3 Hub wheels 4. Inner Ring 5. Inner ball row 6 Outer ball rows 7. Ball (rolling element) 8 Cage 10 Outer side sealing member 11 Mandrel 12 sealing 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, The outer member comprises a core metal fitted to the inner circumference of the outer member and a sealing member joined to the core metal. The core metal has an inner fitting portion that fits onto the inner circumference of the outer member, and a vertical plate portion that extends outward from one axial end of the inner fitting portion. The sealing member has a projection that protrudes from the vertical plate portion toward the other side in the axial direction, The aforementioned vertical plate portion is a sealing device that is tilted to the other side of the axial direction with respect to a direction perpendicular to the axial direction.

2. The sealing member has an other side portion joined to the other side of the vertical plate portion in the axial direction, a projection that protrudes from the other side portion in the axial direction, and a recess formed around the projection that is recessed in one direction from the surface of the other side portion in the axial direction. The axial height C of the projection from the surface on the other side portion and the axial depth D of the recess from the surface on the other side portion are, 0.2 × C ≤ D ≤ 0.3 × C A sealing device according to claim 1 having the relationship described above.

3. An outer member having double rows of outer raceway surfaces on its inner circumference, An inner member having double rows of inner raceway surfaces opposite to the double rows of outer raceway surfaces, A double row of rolling elements is rotatably housed between the raceway surfaces of the outer member and the inner member, The sealing device according to claim 1 or claim 2, A wheel bearing device comprising, 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 end and the outer diameter end of the axial end face. The projection of the sealing member is in contact with the axial end face of the outer member. The radial length P between the outer diameter side end of the axial end face and the contact position of the projection with the axial end face, and the radial length A are, 0.2 × A ≤ P ≤ 0.3 × A A wheel bearing device having a relationship.

4. 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, The fitting length L of the inner fitting portion with respect to the outer member in the axial direction is: L ≥ 0.4 × B A wheel bearing device according to claim 3, having the relationship described above.

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