Sealing device

Abstract

In the present invention, a hub seal (1) is provided with: a seal body (3) that is fixed to an outer ring (101); and a slinger (4) that is fixed to an inner ring (102). The seal body (3) is provided with: a reinforcing ring (10); and an elastic body (20) that is attached to the reinforcing ring (10) and formed from an elastic material. The elastic body (20) has a multi-level lip (30) that extends inward and comes into contact with the slinger (4). The multi-level lip (30) is bent toward the tip end in multiple stages on the outer circumferential side.

Description

Sealing device

[0001] The present invention relates to a sealing device.

[0002] In a vehicle, such as an automobile, a hub seal, which is a sealing device, has conventionally been attached to a hub bearing that rotatably supports a wheel in order to seal a gap formed between an outer ring and an inner ring. The hub seal seals the lubricant inside the hub bearing and prevents foreign matters such as rainwater, muddy water, and dust from entering the inside. Since the hub bearing is in a harsh environment directly exposed to foreign matters such as rainwater, muddy water, and dust, the hub seal is required to improve the sealing performance against foreign matters.

[0003] On the other hand, due to requirements such as fuel efficiency improvement, the hub seal is required to reduce the sliding resistance (torque resistance) applied to the hub bearing by the seal lip. For this reason, various hub seals for reducing the torque resistance have been proposed (see, for example, Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2019-196796

[0005] However, further reduction of torque resistance is required for conventional hub seals. Thus, for a sealing device applied to an object used in a harsh environment with respect to the entry of foreign matters, such as a hub bearing, a configuration that can further reduce the torque resistance while maintaining or improving the sealing performance against foreign matters is required.

[0006] The present invention has been made in view of the above problems, and an object thereof is to provide a sealing device capable of reducing torque resistance while suppressing a decrease in sealing performance against foreign matters.

[0007] To achieve the above objective, the sealing device according to the present invention is a sealing device for sealing a gap between an outer peripheral member that is rotatable relative to each other about an axis and an inner peripheral member that is at least partially surrounded by the outer peripheral member, comprising a sealing device body fixed to the outer peripheral member and a slinger fixed to the inner peripheral member, wherein the sealing device body comprises an annular reinforcing ring about the axis and an elastic body portion attached to the reinforcing ring and formed from an annular elastic body about the axis, the elastic body portion has an annular lip extending toward one side in the axial direction and in contact with the slinger, and the lip is bent in multiple stages toward the outer peripheral side toward the tip.

[0008] In a sealing device according to one aspect of the present invention, the lip is configured to contact the slinger with a surface facing the inner circumference.

[0009] In a sealing device according to one aspect of the present invention, the lip is curved so as to be recessed on the inner circumference side.

[0010] In a sealing device according to one aspect of the present invention, the portion of the lip between the tip and the bent portion adjacent to the tip is widened in diameter toward the tip.

[0011] In a sealing device according to one aspect of the present invention, the lip has a plurality of cylindrical portions, which are cylindrical parts, around the axis, and the plurality of cylindrical portions are connected along the axis, and two adjacent cylindrical portions are connected to each other by forming the step.

[0012] In a sealing device according to one aspect of the present invention, the lip is bent in two stages and has three cylindrical portions.

[0013] In a sealing device according to one aspect of the present invention, the elastic body further has at least one other annular lip extending toward one side in the axial direction and in contact with the slinger, wherein the lip and the other lip are arranged radially.

[0014] In a sealing device according to one aspect of the present invention, the lip is provided on the inner circumference side than the other lip.

[0015] A sealing device according to one aspect of the present invention comprises a plurality of the lips, the lips being arranged radially.

[0016] In a sealing device according to one aspect of the present invention, the slinger has a fitting portion which is a cylindrical portion extending along the axis and an annular portion which is an annular portion extending radially from one end of the fitting portion, and the lip is configured to contact the annular portion of the slinger.

[0017] One aspect of the present invention is a sealing device used in a hub bearing, which is a hub seal.

[0018] The sealing device according to the present invention can reduce torque resistance while suppressing a decrease in sealing performance against foreign matter.

[0019] This is a cross-sectional view showing a plane containing the axis of a hub bearing as an example. This is a partially enlarged cross-sectional view of the vicinity of the hub seal in Figure 1. This is a cross-sectional view showing a plane containing the axis of the seal body. This is an enlarged cross-sectional view showing the multi-stage lip of the seal body and its vicinity as shown in Figure 3. This is a cross-sectional view of an example of an in-wheel motor unit as an example of an application of the present invention.

[0020] Embodiments of the present invention will be described below with reference to the drawings. In the drawings, not all of the components are assigned reference numerals, and some of the reference numerals for components may be omitted.

[0021] The sealing device according to the present invention is a sealing device that seals the gap between an outer peripheral member and an inner peripheral member that are rotatable relative to each other about an axis. The inner peripheral member is at least partially surrounded by the outer peripheral member. The sealing device according to the present invention is applied to, for example, a hub bearing. Figure 1 is a cross-sectional view showing a plane containing the axis of a hub bearing 100 as an example. As shown in Figure 1, the hub bearing 100 is a conventionally known hub bearing, which is installed in vehicles such as trucks and passenger cars, and rotatably supports a wheel in an axle or suspension system. Note that the sealing device according to the present invention is not limited to a hub seal, and the application of the sealing device according to the present invention is not limited to a hub bearing.

[0022] Specifically, as shown in Figure 1, the hub bearing 100 comprises an annular outer ring 101 as an outer peripheral member with axis x as its central axis or substantially central axis, an inner ring 102 as an inner peripheral member that is rotatable relative to the outer ring 101 and partially surrounded by the outer ring 101 with axis x as its central axis or substantially central axis, and a plurality of bearing balls (rolling elements) 103 disposed between the outer ring 101 and the inner ring 102. In the operating state of the hub bearing 100 attached to a vehicle or the like, the outer ring 101 is fixed, and the inner ring 102 becomes rotatable relative to the outer ring 101. Specifically, the inner ring 102 has an inner ring member 104 and a hub ring 105, and the hub ring 105 has a cylindrical or substantially cylindrical shaft portion 105a extending along axis x and a wheel mounting flange 105b. The wheel mounting flange 105b is a disc-shaped portion that extends outward from one outer end of the shaft portion 105a towards the outer circumference, and is the portion to which a brake disc rotor and tire wheel (not shown) are attached by multiple hub bolts (not shown). The shaft portion 105a and the wheel mounting flange 105b are smoothly connected on the inner circumference. The inner ring member 104 is fitted to the inner end of the shaft portion 105a of the hub ring 105 in order to hold the bearing balls 103 in the internal space S, which is the gap between the outer ring 101 and the inner ring 102. Within the internal space S between the outer ring 101 and the inner ring 102, the bearing balls 103 are held by a cage 106.

[0023] The outer ring 101 has a through hole 107 extending in the axial x direction, into which the shaft portion 105a of the hub ring 105 of the inner ring 102 is inserted, forming an annular internal space S extending along the axial x between the shaft portion 105a and the through hole 107. In this internal space S, as described above, bearing balls 103 are housed and held by a cage 106, and lubricant is applied or injected. A sealing device 1 is attached to the inner opening 101a of the outer ring 101, which forms an opening that opens the internal space S between the inner ring member 104 and the shaft portion 105a and the through hole 107 to the inside. On the other hand, a sealing device 2 is attached to the outer opening 101b of the outer ring 101, which forms an opening that opens the internal space S to the outside.

[0024] Sealing device 1 is a sealing device according to an embodiment of the present invention and is an inner hub seal. On the other hand, sealing device 2 is a conventionally known hub seal and is an outer hub seal. Sealing devices 1 and 2 seal the shaft portion 105a of the hub ring 105 and the internal space S between the inner ring member 104 and the outer ring 101, preventing lubricant in the internal space S from leaking out to the outside and preventing foreign matter such as rainwater, mud, and dust from entering the internal space S from the outside. Note that sealing device 2 may be a sealing device according to the present invention. In this case, sealing device 2 has the same configuration as sealing device 1, but its specific form, such as shape and size, corresponds to the part of the hub bearing 100 to which sealing device 2 is attached. Furthermore, the configuration of the hub bearing to which sealing devices 1 and 2 are applied is not limited to the configuration of the hub bearing 100 described above. In the following description, the sealing device applied to the hub bearing is also called a hub seal.

[0025] Next, a hub seal 1 according to an embodiment of the present invention will be described. Figure 2 is a partially enlarged cross-sectional view of the vicinity of the hub seal 1 in Figure 1. Figure 2 shows one side of the cross-section of the hub seal 1 with respect to the axis x, in a plane containing the axis x, in a working state attached to the hub bearing 100. In the working state of the hub seal 1, the seal body 3 and the slinger 4 are attached to the hub bearing 100 so as to be in a predetermined relative position.

[0026] As shown in Figure 2, the hub seal 1 comprises a seal body 3, which is the main body of the sealing device fixed to the outer ring 101, and a slinger 4, which is fixed to the inner ring 102. The seal body 3 comprises an annular reinforcing ring 10 about the axis x, and an elastic body portion 20 attached to the reinforcing ring 10 and formed from an annular elastic material about the axis x. The elastic body portion 20 has a multi-stage lip 30, which is an annular lip that extends toward one side (inward) in the direction of the axis x and comes into contact with the slinger 4. The multi-stage lip 30 is bent in multiple stages toward the outer circumference toward the tip. The configuration of the hub seal 1 will be described in detail below.

[0027] The inner side is the side in the direction of arrow a in the axis x direction, as shown in Figures 1 and 2, while the outer side is the side in the direction of arrow b in the axis x direction, as shown in Figures 1 and 2. In a hub bearing 100 mounted on a vehicle, the inner side is the body side, and the outer side is the wheel side. The radial direction is the direction perpendicular to the axis x. The outer circumference side is the side of the hub bearing 100 that moves away from the axis x in the radial direction, as shown in Figure 1, in the direction of arrow c, while the inner circumference side is the side of the hub bearing 100 that moves closer to the axis x in the radial direction, as shown in Figure 1, in the direction of arrow d. The axis x of the hub seal 1 mounted on the hub bearing 100 coincides with or approximately coincides with the axis of the hub bearing 100. For the sake of explanation, the axis of the hub bearing 100 will be referred to as axis x.

[0028] The reinforcing ring 10 is an annular, plate-shaped metal member with axis x as its central axis or approximately its central axis, as shown in Figure 2, for example, and is formed to be press-fitted into the through hole 107 of the outer ring 101 of the hub bearing 100. By press-fitting the reinforcing ring 10 into the outer ring 101, the seal body 3 is fixed to the outer ring 101. The reinforcing ring 10 has, for example, a cylindrical portion 11 and a lip support portion 12 that curves inward from the outer end of the cylindrical portion 11 and extends to the inner circumference.

[0029] Figure 3 is a cross-sectional view showing a cross-section of the seal body 3 along a plane containing the axis x. Note that only one side of the cross-section of the seal body 3 with respect to the axis x is shown in Figure 3. Also, Figure 3 shows the seal body 3 in a free state where no external force is applied. As shown in Figures 2 and 3, the cylindrical portion 11 has, for example, an outer fitting portion 11a and an inner gasket support portion 11b. The fitting portion 11a is, for example, a cylindrical or substantially cylindrical portion with the axis x as its central axis or substantially its central axis. The cylindrical portion 11 is formed such that, as shown in Figures 1 and 2, the outer peripheral surface 11c, which is the outer peripheral surface of the fitting portion 11a, is press-fitted into the inner opening 101a of the outer ring 101 and fitted to its inner peripheral surface 101c. The gasket support portion 11b extends from the inner end of the fitting portion 11a, and the outer peripheral surface 11d of the gasket support portion 11b is located on the inner peripheral side than the outer peripheral surface 11c of the fitting portion 11a.

[0030] The lip support portion 12 is shaped such that, for example, a seal lip including a multi-stage lip 30 is positioned in the hub seal 1 at a desired position relative to the slinger 4. The lip support portion 12 has a return portion 12a and a lip flange portion 12b, as shown in Figures 2 and 3. The return portion 12a is, for example, an annular plate-shaped portion that extends radially from the outer end of the cylindrical portion 11 and then curves inward and extends inclined with respect to the radial direction. The lip flange portion 12b is, for example, an annular plate-shaped portion that extends inward from the inner end of the return portion 12a. The reinforcing ring 10 is formed as a single member from a metal plate by pressing or forging, for example, and the cylindrical portion 11 and the lip support portion 12 are parts of the reinforcing ring 10 formed integrally from the same material and are integrally continuous. Examples of the metal material for the reinforcing ring 10 include stainless steel and SPCC (cold-rolled steel).

[0031] The elastic body portion 20 is attached to the reinforcing ring 10 as described above, and is integral with the reinforcing ring 10 so as to cover the reinforcing ring 10 from the inside, as shown in Figures 2 and 3. In addition to the multi-stage lip 30, the elastic body portion 20 has, for example, at least one other lip. The other lip is an annular sealing lip that extends inward in the axial x direction, similar to the multi-stage lip 30, and is in contact with the slinger 4. The multi-stage lip 30 and the other lip are arranged radially. The elastic body portion 20 may have multiple multi-stage lips 30.

[0032] As shown in Figures 2 and 3, the elastic body portion 20, as an example, has one multi-stage lip 30 and one side lip 21, and also has a grease lip 22. The side lip 21 is a lip other than the multi-stage lip 30, and is not bent in multiple stages, for example, a lip of a known form. The multi-stage lip 30, the side lip 21, and the grease lip 22 are each annular sealing lips around the axis x. As shown in Figures 2 and 3, the grease lip 22 extends toward the axis x (inner circumference side) and is made to contact the fitting portion 41 of the slinger 4, which will be described later. The multi-stage lip 30 and the side lip 21 contact the flange portion 42 of the slinger 4, which will be described later, to prevent foreign matter from entering the internal space S of the hub bearing 100, and also to prevent lubricant from flowing out of the internal space S. The grease lip 22 also prevents lubricant from flowing out of the internal space S of the hub bearing 100.

[0033] Furthermore, the elastic body portion 20 has, for example, a base portion 23. As shown in Figures 2 and 3, the multi-stage lip 30 and the grease lip 22 extend from the inner circumferential end of the base portion 23, respectively. The side lip 21 extends from the base portion 23, radially spaced away from the multi-stage lip 30, on the outer circumferential side of the multi-stage lip 30, as shown in Figures 2 and 3. The base portion 23 is the part of the elastic body portion 20 that extends mainly to the inner surface of the reinforcing ring 10, spanning the cylindrical portion 11 and the lip support portion 12 of the reinforcing ring 10. Also, as shown in Figures 2 and 3, for example, the base portion 23 extends to the outer circumferential surface 11d of the gasket support portion 11b of the reinforcing ring 10, forming a gasket portion 23a on the outer circumferential surface 11d of the gasket support portion 11b. As shown in Figures 2 and 3, the gasket portion 23a protrudes outward from the outer peripheral surface 11c of the fitting portion 11a, and is compressed radially between the gasket support portion 11b of the reinforcing ring 10 fitted to the inner opening 101a of the outer ring 101 and the inner peripheral surface 101c of the inner opening 101a. This ensures a seal between the inner opening 101a of the outer ring 101 and the seal body 3.

[0034] As shown in Figures 2 and 3, the side lip 21 specifically extends inward from the base portion 23 in an annular shape with the axis x as the central axis or approximately the central axis. Also, as shown in Figure 2, in the operating state of the hub seal 1, which is attached to the hub bearing 100 so that the seal body 3 and the slinger 4 are in a predetermined relative position, the side lip 21 is formed so that its tip contacts the flange portion 42 of the slinger 4, which will be described later, with a predetermined overlap. Specifically, the inner circumferential surface 21a at the tip of the side lip 21 contacts the flange portion 42 of the slinger 4. The inner circumferential surface 21a of the side lip 21 is an annular surface facing the inner circumference of the side lip 21. As shown in Figure 3, the side lip 21 has a conical or approximately conical shape that expands in diameter as it extends inward in the direction of the axis x.

[0035] As described above, the multi-stage lip 30 is bent in multiple stages toward the outer circumference towards the tip, and as shown in Figure 3, it has multiple bent portions 31 that form multiple stages. Also, as shown in Figure 3, the multi-stage lip 30 is curved so as to be concave toward the inner circumference. As shown in Figures 2 and 3, the multi-stage lip 30 has an outer surface 30a, which is an annular surface facing the outer circumference, and an inner surface 30b, which is an annular surface facing the inner circumference. The outer surface 30a and the inner surface 30b are facing away from each other. The tip 30c is the inner end of the multi-stage lip 30 and is an annular surface that extends between the inner end of the outer surface 30a and the inner end of the inner surface 30b. The multi-stage lip 30 is configured to contact the slinger 4 at the inner surface 30b.

[0036] Specifically, as shown in Figure 3, the portion between the tip 30c of the multi-stage lip 30 and the bent portion 31 adjacent to the tip 30c expands in diameter toward the tip 30c. The multi-stage lip 30 has multiple cylindrical portions 32, which are cylindrical parts, around an axis x, as shown in Figure 3, for example. The multiple cylindrical portions 32 are connected along the axis x, and two adjacent cylindrical portions 32 are connected to each other by forming a step. In other words, the portion where two adjacent cylindrical portions 32 are connected is the bent portion 31. The multi-stage lip 30 is, for example, an intermediate lip.

[0037] As shown in Figures 2 and 3, the multi-stage lip 30 has an outer circumferential surface 30a, which is an annular surface facing the outer circumference, and an inner circumferential surface 30b, which is an annular surface facing the inner circumference. The outer circumferential surface 30a and the inner circumferential surface 30b are facing away from each other. As shown in Figures 2 and 3, the multi-stage lip 30 has an annular contact surface 35b on the inner circumferential surface 30b, and the contact surface 35b is configured to contact the flange portion 42 of the slinger 4. Specifically, for example, a part of the tip 30c side of the contact surface 35b is configured to contact the flange portion 42 of the slinger 4.

[0038] As shown in Figures 2 to 4, as an example, the multi-stage lip 30 is bent in two stages, and is a two-stage lip, having two bent portions 31a and 31b as the bent portion 31, and three cylindrical portions 33 to 35 as the cylindrical portion 32. Figure 4 is an enlarged cross-sectional view showing the multi-stage lip 30 of the seal body 3 and its vicinity in the free state.

[0039] The multi-stage lip 30 has, for example, a base portion 33 as a cylindrical portion 32. The base portion 33 is the part of the multi-stage lip 30 that is at the base and is the part where the multi-stage lip 30 connects to the base portion 23. As shown in Figures 3 and 4, the base portion 33 is specifically a cylindrical portion with axis x as its central axis or approximate central axis. For example, as shown in Figures 3 and 4, the base portion 33 is tapered in diameter as it moves inward along axis x. Specifically, for example, as shown in Figures 3 and 4, the base portion 33 is a conical or approximately conical cylindrical portion with axis x as its central axis or approximate central axis.

[0040] The base portion 33 of the multi-stage lip 30 has the shape described above, and the outer circumferential surface 30a is specifically a cylindrical surface with axis x as the central axis or approximately the central axis in the base portion 33. For example, as shown in Figures 3 and 4, the outer circumferential surface 30a in the base portion 33 decreases in diameter as it moves inward along axis x. Specifically, for example, as shown in Figures 3 and 4, the outer circumferential surface 30a in the base portion 33 is a conical cylindrical surface or approximately conical cylindrical surface with axis x as the central axis or approximately the central axis. In other words, as shown in Figures 3 and 4, in cross-section, the outer circumferential surface 30a in the base portion 33 draws a straight line or approximately straight line that slopes outward with respect to the radial direction toward the outer circumferential side. Note that the specific example of the outer circumferential surface 30a in the base portion 33 is not limited to a conical cylindrical surface; as long as the outer circumferential surface 30a in the base portion 33 is inclined with respect to the radial direction as described above, it may be a surface that draws a curve in cross-section, or a surface that draws a line consisting of a combination of a curve and a straight line in cross-section. The inner circumferential surface 30b of the base portion 33 extends along the outer circumferential surface 30a, as shown in Figures 3 and 4, for example, and extends parallel to or substantially parallel to the outer circumferential surface 30a.

[0041] The multi-stage lip 30 has, for example, an intermediate portion 34 as a cylindrical portion 32. The intermediate portion 34 is the middle part of the multi-stage lip 30 and is the part that connects to the base portion 33 from the inside. As shown in Figures 3 and 4, the part where the base portion 33 and the intermediate portion 34 connect to each other is a bent portion 31a, and the intermediate portion 34 is bent outward relative to the base portion 33. In other words, in the direction of extension along the axis x of the base portion 33, the intermediate portion 34 is bent outward relative to the base portion 33 inward. As shown in Figures 3 and 4, the base portion 33 and the intermediate portion 34 form an annular groove on the outer surface 30a that is recessed inward. As shown in Figures 3 and 4, the intermediate portion 34 is specifically a cylindrical portion with the axis x as its central axis or approximate central axis. For example, as shown in Figures 3 and 4, the intermediate portion 34 expands in diameter as it extends inward along the axis x. Specifically, as shown in Figures 3 and 4, the intermediate portion 34 is a conical or approximately conical cylindrical portion with axis x as its central axis or approximate central axis.

[0042] The intermediate portion 34 of the multi-stage lip 30 has the configuration described above, and the outer circumferential surface 30a is specifically a cylindrical surface in the intermediate portion 34 with axis x as the central axis or approximately the central axis. For example, as shown in Figures 3 and 4, the outer circumferential surface 30a in the intermediate portion 34 expands in diameter as it moves inward along axis x. Specifically, for example, as shown in Figures 3 and 4, the outer circumferential surface 30a in the intermediate portion 34 is a conical cylindrical surface or approximately conical cylindrical surface with axis x as the central axis or approximately the central axis. In other words, as shown in Figures 3 and 4, in cross-section, the outer circumferential surface 30a in the intermediate portion 34 draws a straight line or approximately straight line that slopes inward with respect to the radial direction toward the outer circumferential side. Note that the specific example of the outer circumferential surface 30a in the intermediate portion 34 is not limited to a conical cylindrical surface; as long as the outer circumferential surface 30a in the intermediate portion 34 is inclined with respect to the radial direction as described above, it may be a surface that draws a curve in cross-section, or a surface that draws a line consisting of a combination of a curve and a straight line in cross-section. The inner circumferential surface 30b of the intermediate portion 34 extends along the outer circumferential surface 30a, as shown in Figures 3 and 4, for example, and extends parallel to or substantially parallel to the outer circumferential surface 30a.

[0043] The multi-stage lip 30 has, for example, a tip portion 35 as a cylindrical portion 32. The tip portion 35 is a portion on the tip side of the multi-stage lip 30, a portion that connects to the intermediate portion 34 from the inside, and extends to the tip 30c. As shown in FIGS. 3 and 4, the portion where the intermediate portion 34 and the tip portion 35 are connected to each other is a bent portion 31b, and the tip portion 35 is bent outward with respect to the intermediate portion 34. That is, the tip portion 35 is bent outward with respect to the intermediate portion 34 toward the inside in the extending direction along the axis x of the intermediate portion 34. As shown in FIGS. 3 and 4, the intermediate portion 34 and the tip portion 35 form an annular groove that is recessed inward on the outer peripheral surface 30a. As shown in FIGS. 3 and 4, specifically, the tip portion 35 is a cylindrical portion having the axis x as the central axis or substantially the central axis. For example, as shown in FIGS. 3 and 4, the tip portion 35 expands in diameter as it goes inward along the axis x. Specifically, for example, as shown in FIGS. 3 and 4, the tip portion 35 is a conical cylindrical or substantially conical cylindrical portion having the axis x as the central axis or substantially the central axis.

[0044] The tip portion 35 of the multi-stage lip 30 has the form as described above, and the outer peripheral surface 30a is, specifically, a cylindrical surface having the axis x as the central axis or substantially the central axis at the tip portion 35. For example, as shown in FIGS. 3 and 4, at the tip portion 35, the outer peripheral surface 30a expands in diameter as it goes inward along the axis x. Specifically, for example, as shown in FIGS. 3 and 4, at the tip portion 35, the outer peripheral surface 30a is a conical cylindrical surface or a substantially conical cylindrical surface having the axis x as the central axis or substantially the central axis. That is, as shown in FIGS. 3 and 4, in the cross section, the outer peripheral surface 30a at the tip portion 35 depicts a straight line or a substantially straight line that inclines inward with respect to the radial direction toward the outer peripheral side in the radial direction. Note that the specific example of the outer peripheral surface 30a at the tip portion 35 is not limited to a conical cylindrical surface, and the outer peripheral surface 30a at the tip portion 35 may be a surface that depicts a curve in the cross section as long as it is inclined with respect to the radial direction as described above, or may be a surface that depicts a line composed of a combination of a curve and a straight line in the cross section. The contact surface 35b, which is the inner peripheral surface 30b at the tip portion 35, extends along the outer peripheral surface 30a, for example, as shown in FIGS. 3 and 4, and extends parallel or substantially parallel to the outer peripheral surface 30a.

[0045] The contact surface 35b, which is the inner circumferential surface 30b of the tip portion 35, is connected to the tip 30c at its inner end, as shown in Figures 3 and 4. The multi-stage lip 30 contacts the slinger 4 at the contact surface 35b when the hub seal 1 is in use, as will be described later. As mentioned above, the contact surface 35b faces the inner circumferential side. In other words, the cross-section of the contact surface 35b is inclined radially toward the inner circumferential side and radially outward.

[0046] The shape of the base portion 33 is not limited to the shape described above. In other words, the base portion 33 does not have to decrease in diameter as it extends inward along the axis x. For example, the base portion 33 may extend parallel to or approximately parallel to the axis x, and may also increase in diameter as it extends inward along the axis x. Similarly, the shape of the intermediate portion 34 is not limited to the shape described above. In other words, the intermediate portion 34 does not have to increase in diameter as it extends inward along the axis x. For example, the intermediate portion 34 may extend parallel to or approximately parallel to the axis x, and may also decrease in diameter as it extends inward along the axis x. However, the shapes of the base portion 33 and the intermediate portion 34 are limited to those in which the tip portion 35 increases in diameter as it extends inward along the axis x, and the contact surface 35b contacts the flange portion 42 of the slinger 4, as described above.

[0047] The multi-stage lip 30 has the shape described above, and the specific form of each part, such as the length and thickness in the extension direction, is such that it can form the desired clamping force and lip reaction force based on the form and requirements of the specific application. The lip reaction force is the reaction force that the flange portion 42 receives from the multi-stage lip 30 pressed against the flange portion 42 of the slinger 4 in the hub seal 1 in use.

[0048] The bending angles α1 and α2 in the bent portions 31a and 31b are set such that, for example, the inclination angle θ1 of the contact surface 35b becomes a predetermined angle. As shown in FIGS. 3 and 4, the bending angle α1 is the angle between the base portion 33 and the intermediate portion 34 in the multi-stage lip 30 in the free state where no external force is applied, and is a value indicating how much the intermediate portion 34 is bent with respect to the base portion 33. For example, as shown in FIGS. For example, the bending angle α1 is an angle sandwiched between the outer peripheral surface 30a of the base portion 33 and the outer peripheral surface 30a of the intermediate portion 34 in a cross-section by a plane including the axis x. The bending angle α1 may be a value set by other methods. For example, in a cross-section by a plane including the axis x, it may be an angle sandwiched between the inner peripheral surface 30b of the base portion 33 and the inner peripheral surface 30b of the intermediate portion 34. Further, the bending angle α2 is the angle between the intermediate portion 34 and the tip portion 35 in the multi-stage lip 30 in the free state where no external force is applied, and is a value indicating how much the tip portion 35 is bent with respect to the intermediate portion 34. For example, as shown in FIGS. 3 and 4, the bending angle α2 is an angle sandwiched between the outer peripheral surface 30a of the intermediate portion 34 and the outer peripheral surface 30a of the tip portion 35 in a cross-section by a plane including the axis x. The bending angle α2 may be a value set by other methods. For example, in a cross-section by a plane including the axis x, it may be an angle sandwiched between the inner peripheral surface 30b of the intermediate portion 34 and the inner peripheral surface 30b of the tip portion 35.

[0049] The inclination angle θ1 is the angle of the contact surface 35b of the multi-stage lip 30 in a free state where no external force is applied, as shown in Figures 3 and 4, and indicates how much the contact surface 35b is inclined with respect to the surface it is contacting. For example, the inclination angle θ1 is the angle of the contact surface 35b with respect to a plane perpendicular to the axis x, and specifically, as shown in Figures 3 and 4, it is the angle between the contact surface 35b and the plane perpendicular to the axis x in a cross-section formed by a plane containing the axis x. The inclination angle θ1 of the contact surface 35b is set, for example, based on the contact angle θ2 of the contact surface 35b, which will be described later. The contact angle θ2 of the contact surface 35b is the angle between the contact surface 35b and the contact surface 42a of the flange portion 42 of the slinger 4 in the multi-stage lip 30 in use, as shown in Figure 2.

[0050] The grease slip 22 extends annularly from the base portion 23 toward the outer and inner circumference with axis x as the central axis or substantially the central axis, as shown in Figures 2 to 4, for example. As shown in Figure 2, the tip 22a of the grease slip 22 is in contact with the fitting portion 41 of the slinger 4 when the hub seal 1 is in use. Note that the hub seal 1 does not necessarily have a grease slip 22. Also, the tip 22a of the grease slip 22 may not be in contact with the fitting portion 41 of the slinger 4, as long as the grease can be sealed.

[0051] The elastic body portion 20 is integrally attached to the reinforcing ring 10, and the aforementioned side lip 21, multi-stage lip 30, grease lip 22, and base portion 23 are each part of the elastic body portion 20 formed integrally from the same material and are integrally continuous. The elastic body of the elastic body portion 20 can be, for example, various rubber materials. These various rubber materials are synthetic rubbers such as nitrile rubber (NBR), hydrogenated nitrile rubber (H-NBR), acrylic rubber (ACM), and fluororubber (FKM).

[0052] The hub seal 1 may also be equipped with grease G. For example, as shown in Figures 2 to 4, the grease G is applied to the contact surface 35b of the tip portion 35 of the multi-stage lip 30 and to the tip portion of the inner circumferential surface 21a, which is the contact surface of the side lip 21.

[0053] As shown in Figures 1 and 2, the slinger 4 has a fitting portion 41 which is a cylindrical portion extending along the axis x, and a flange portion 42 which is an annular portion extending radially from the inner end of the fitting portion 41. As described above, the side lip 21 and the multi-stage lip 30 are in contact with the flange portion 42 of the slinger 4. The slinger 4 is a metal plate-shaped member that is an annular or substantially annular in shape with the axis x as its central axis or substantially its central axis, and as shown in Figures 1 and 2, it is formed to be press-fitted into the inner ring member 104 of the inner ring 102 of the hub bearing 100 and fitted into the inner ring member 104.

[0054] The fitting portion 41 is a cylindrical or substantially cylindrical portion with axis x as its central axis or substantially central axis, as shown in Figure 2, for example, and is formed to fit onto the outer circumferential surface 104a of the inner ring member 104. The contact surface 41a, which faces the outer circumferential side of the fitting portion 41, is a cylindrical or substantially cylindrical surface with axis x as its central axis or substantially central axis, as shown in Figure 2, for example. The flange portion 42 is a disc-shaped or substantially disc-shaped portion that extends radially with axis x as its central axis or substantially central axis, and as shown in Figure 2, forms an annular portion that protrudes radially from the outer circumferential surface 104a of the inner ring member 104. The contact surface 42a, which faces the outside of the flange portion 42, is a surface that extends on a plane parallel or substantially parallel to a plane perpendicular to axis x, for example.

[0055] Furthermore, the slinger 4 is designed to be in close contact with the inner ring member 104. Specifically, the fitting portion 41 of the slinger 4 and the inner ring member 104 are designed to be in close contact with each other so that no gap is formed between the fitting portion 41 and the inner ring member 104 through which foreign matter can pass. However, the slinger 4 and the inner ring member 104 do not necessarily have to be in close contact as described above. In this case, for example, an annular gasket may be provided between the slinger 4 and the inner ring member 104 to prevent foreign matter from entering the internal space S between the outer ring 101 and the inner ring 102 through the gap between the slinger 4 and the inner ring member 104.

[0056] The slinger 4 is formed integrally from a metal plate of uniform thickness, for example, by pressing or forging, and the fitting portion 41 and flange portion 42 are integrally formed parts of the slinger 4. Examples of metal materials for the slinger 4 include stainless steel and SPCC (cold-rolled steel).

[0057] Next, the operation of the hub seal 1 will be explained. The seal body 3 is attached to the outer ring 101 of the hub bearing 100, and the slinger 4 is attached to the inner ring member 104 of the hub bearing 100, so that the seal body 3 and the slinger 4 are in a predetermined relative position. The hub seal 1 is then in a working state attached to the hub bearing 100.

[0058] In the operating state of the hub seal 1, the side lip 21 of the seal body 3 is in contact with the contact surface 42a of the flange portion 42 of the slinger 4, and the multi-stage lip 30 of the seal body 3 is also in contact with the contact surface 42a of the flange portion 42 of the slinger 4. This primarily prevents foreign matter such as rainwater, mud, and dust from entering the internal space S of the hub bearing 100 from the outside. In addition, in the operating state of the hub seal 1, the grease lip 22 of the seal body 3 is in contact with the contact surface 41a of the fitting portion 41 of the slinger 4. This primarily prevents lubricant from leaking out of the internal space S of the hub bearing 100.

[0059] Furthermore, in the operating state of the hub seal 1, the reinforcing ring 10 of the seal body 3 is fitted onto the inner circumferential surface 101c of the inner opening 101a of the outer ring 101 of the hub bearing 100, and the gasket portion 23a is pressed against the inner circumferential surface 101c, thereby ensuring a tight seal between the hub seal 1 and the inner circumferential surface 101c of the inner opening 101a of the outer ring 101.

[0060] The hub seal 1 has the configuration described above, and in the operating state of the hub seal 1, the contact surface 35b of the tip portion 35 of the multi-stage lip 30 is in contact with the contact surface 42a of the flange portion 42 of the slinger 4. In the operating state, the contact surface 35b of the multi-stage lip 30 is in contact with the contact surface 42a of the slinger 4 with a predetermined overlap, and the angle between the contact surface 35b of the multi-stage lip 30 and the contact surface 42a of the slinger 4 is the contact angle θ2. The contact angle θ2 is set to a predetermined value and is set to a small angle less than or equal to the predetermined angle. For example, the contact angle θ2 of the multi-stage lip 30 is smaller than the contact angle θ3 of the side lip 21. The contact angle θ3 of the side lip 21 is the angle sandwiched between the inner circumferential surface 21a of the side lip 21 and the contact surface 42a of the slinger 4 in the operating state, as shown in Figure 2.

[0061] As described above, the bending angles α1, α2 and inclination angle θ1 of the multi-stage lip 30 are set so that the contact angle θ2 of the multi-stage lip 30 is small. Because the contact angle θ2 of the multi-stage lip 30 is small, the grease G applied to the contact surface 35b of the tip portion 35 is supplied in large quantities to the sliding point P, which is the part where the contact surface 35b of the multi-stage lip 30 and the flange portion 42 of the slinger 4 come into contact, due to the centrifugal force when the hub bearing 100 rotates. This reduces the torque resistance of the multi-stage lip 30 to the flange portion 42 of the slinger 4.

[0062] Furthermore, the multi-stage lip 30 is bent in multiple stages, and therefore, in the operating state, the reaction force that the multi-stage lip 30 exerts on the slinger 4 can be reduced by contact with the multi-stage lip 30. For example, the reaction force of the multi-stage lip 30 is smaller than the reaction force of the side lip 21. Therefore, in this respect as well, the multi-stage lip 30 can reduce the torque resistance of the flange portion 42 of the slinger 4.

[0063] Furthermore, in use, the multi-stage lip 30 contacts the flange portion 42 of the slinger 4 with a predetermined tightening allowance, as described above, preventing or suppressing the sealing performance of the multi-stage lip 30 from being inferior to that of the side lip 21. In addition, because the contact angle θ2 of the multi-stage lip 30 is small, the multi-stage lip 30 is less prone to wear due to contact with the slinger 4, thus improving its durability.

[0064] Furthermore, the side lip 21 is provided on the outer circumference side of the multi-stage lip 30, and the side lip 21 is located on the upstream side of the foreign object entry path. Therefore, the multi-stage lip 30 only needs to have sealing performance against foreign objects that have entered beyond the side lip 21, and a decrease in the overall sealing performance of the hub seal 1 is prevented or suppressed.

[0065] Thus, according to the hub seal 1 of this embodiment, it is possible to reduce torque resistance while suppressing a decrease in sealing performance against foreign matter.

[0066] In the above-described embodiment, the seal body 3 has one side lip 21 on the outer circumference and one multi-stage lip 30 on the inner circumference, but the form of the seal body 3 is not limited to this. For example, the seal body 3 may have a multi-stage lip 30 on the outer circumference and a side lip 21 on the inner circumference. Also, for example, the seal body 3 may not have a side lip 21. Also, for example, the seal body 3 may have multiple multi-stage lips 30, or multiple side lips 21. In this case, the multi-stage lip 30 may be provided on the outer circumference side of the side lip 21, the multi-stage lip 30 may be provided between the side lips 21 in the radial direction, and the side lips 21 may be provided between the multi-stage lips 30 in the radial direction.

[0067] Although the present invention has been described above through the embodiments described above, the technical scope of the present invention is not limited to the scope described in the embodiments above. It will be obvious to those skilled in the art that various modifications or improvements can be made to the embodiments described above. It will be clear from the claims that such modified or improved forms may also be included in the technical scope of the present invention.

[0068] The embodiments described above are for the purpose of facilitating understanding of the present invention and are not intended to limit its interpretation. Furthermore, the embodiments described above do not limit the scope of application of the present invention, and the present invention may encompass anything as its target application. The components of the above embodiments, as well as their arrangement, materials, conditions, shapes, and sizes, are not limited to those exemplified and can be modified as appropriate. For example, the present invention includes differences that arise in the implementation of manufacturing tolerances, etc. Furthermore, components shown in different embodiments can be partially substituted or combined to the extent that they do not contradict each other in a technical sense. In addition, each configuration can be selectively combined as appropriate to achieve at least some of the problems and effects described above.

[0069] For example, the sealing device according to the present invention is not limited to hub bearings. Furthermore, the sealing device according to the present invention is not limited to those in which the inner circumferential member rotates relative to the outer circumferential member. For example, as shown in Figure 5, the hub seal 1 can also be applied to an in-wheel motor unit in which the outer circumferential member rotates. An in-wheel motor unit is a drive device in which a hub bearing and a motor are integrated, and is attached to the wheel of a vehicle. It supplies motor output to the wheel via the hub bearing to power the wheel, and also generates electricity by converting the power of the wheel into power via a motor generator.

[0070] Figure 5 is a cross-sectional view of an example of an in-wheel motor unit as an example of an application of the present invention. For example, as shown in Figure 5, the in-wheel motor unit 200 comprises an inner-ring rotating type hub bearing 110, an outer casing 201 as an outer peripheral member attached to the hub bearing 110, an inner casing 202 as an inner peripheral member, and a motor generator 203. Specifically, the outer casing 201 is a cylindrical member and forms an inner space that houses the hub bearing 110. The outer casing 201 is sandwiched between the wheel mounting flange 113 provided on the inner ring 112 of the hub bearing 110 and a brake disc 114 attached to the wheel mounting flange 113, and is fixed between the wheel mounting flange 113 and the brake disc 114 by fixing the wheel to the inner ring 112 with hub bolts 115.

[0071] The inner casing 202 has a cylindrical portion 202a, which is a cylindrical member that forms an inner circumferential space for housing the outer ring 111 of the hub bearing 110, and a disc portion 202b, which is a disc-shaped portion that extends outward from the inner end of the cylindrical portion 202a. The cylindrical portion 202a is shaped such that the outer ring 111 is fitted and fixed into the inner circumferential space. As shown in Figure 5, the outer casing 201 and the inner casing 202 are shaped such that the inner circumferential surface of the outer casing 201 and the outer circumferential surface of the cylindrical portion 202a of the inner casing 202 face each other, forming an annular space between the outer casing 201 and the cylindrical portion 202a. Also, as shown in Figure 5, the inner end (end 201a) of the outer casing 201 faces the disc portion 202b of the inner casing 202 in the axial x direction. An annular gap is formed between the end portion 201a of the outer casing 201 and the disc portion 202b.

[0072] The motor generator 203 is a cylindrical member extending along the axis x, and is provided in the annular space between the outer casing 201 and the cylindrical portion 202a of the inner casing 202. Specifically, the motor generator 203 comprises a rotor 204 and a stator 205, the rotor 204 being fixed to the outer casing 201 and the stator 205 being fixed to the cylindrical portion 202a of the inner casing 202.

[0073] In the in-wheel motor unit 200, the hub seal 1 is provided to prevent foreign matter from entering the interior of the in-wheel motor unit 100 through the annular gap between the end portion 201a of the outer casing 201 and the disc portion 202b of the inner casing 202. For example, as shown in Figure 5, the hub seal 1 is installed between the end portion 201a of the outer casing 201 and the disc portion 202b of the inner casing 202. Specifically, the slinger 4 is press-fitted into the mounting surface 202c of the disc portion 202b of the inner casing 202, and the slinger 4 is fixed to the disc portion 202b of the inner casing 202. Furthermore, the seal body 3 is press-fitted into the mounting surface 201b of the end portion 201a of the outer casing 201, and the seal body 3 is fixed to the outer casing 201. Furthermore, the mounting surface 202c of the disc portion 202b of the inner casing 202 is a cylindrical surface extending along the axis x, and the mounting surface 201b of the end portion 201a of the outer casing 201 is a cylindrical surface extending along the axis x. Also, the mounting surface 201b and the mounting surface 202c face each other in the radial direction.

[0074] 1 Hub seal (sealing device), 2 Sealing device, 3 Seal body (sealing device body), 4 Slinger, 10 Reinforcement ring, 11 Cylinder section, 11a Fitting section, 11b Gasket support section, 11c, 11d Outer surface, 12 Lip support section, 12a Return section, 12b Lip flange section, 20 Elastic body section, 21 Side lip, 21a Inner surface, 22 Grease lip, 22a Tip, 23 Base section, 23a Gasket section, 30 Multi-stage lip, 30a Outer surface, 30b Inner surface, 30c Tip, 31, 31a, 31b Bent section, 32 Cylinder section, 33 Base section, 34 Intermediate section, 35 Tip section, 35b Contact surface, 41 Fitting section, 42 Flange section (ring section), 41a, 42a Contact surface, 100, 110 Hub bearing, 101, 111 Outer ring, 101a Inner opening, 101b Outer opening, 101c Inner circumferential surface, 102, 112 Inner ring, 103 Bearing ball, 104 Inner ring member, 104a Outer circumferential surface, 105 Hub ring, 105a Shaft portion, 105b, 113 Wheel mounting flange, 106 Retainer, 107 Through hole, 114 Brake disc, 115 Hub bolt, 200 In-wheel motor unit, 201 Outer casing, 201a End portion, 201b Mounting surface, 202 Inner casing, 202a Cylindrical portion, 202b Disc portion, 202c Mounting surface, 203 Motor generator, 204 Rotor, 205 Stator, P Contact point, S Internal space, x Axis, α1, α2 Bending angle, θ1 Inclination angle, θ2, θ3 Contact angle

Claims

1. A sealing device for sealing a gap between an outer peripheral member that is rotatable relative to each other about an axis and an inner peripheral member that is at least partially surrounded by the outer peripheral member, comprising: a sealing device body fixed to the outer peripheral member; and a slinger fixed to the inner peripheral member, wherein the sealing device body comprises an annular reinforcing ring about the axis and an elastic body portion attached to the reinforcing ring and formed from an annular elastic body about the axis, the elastic body portion having an annular lip extending toward one side in the axial direction and in contact with the slinger, and the lip being bent in multiple stages toward the outer peripheral side toward the tip.

2. The sealing device according to claim 1, wherein the lip is configured to contact the slinger with a surface facing the inner circumference.

3. The sealing device according to claim 1, wherein the lip is curved so as to be recessed inward.

4. The sealing device according to claim 1, wherein the portion of the lip between the tip and the bent portion adjacent to the tip is widened toward the tip.

5. The sealing device according to any one of claims 1 to 4, wherein the lip has a plurality of cylindrical portions that are cylindrical around the axis, the plurality of cylindrical portions are connected along the axis, and two adjacent cylindrical portions are connected to each other by forming the step.

6. The sealing device according to claim 5, wherein the lip is bent in two stages and has three cylindrical portions.

7. The sealing device according to claim 1, wherein the elastic portion further has at least one other annular lip extending toward one side in the axial direction and in contact with the slinger, the lip and the other lip being arranged radially.

8. The sealing device according to claim 7, wherein the lip is provided on the inner circumference side than the other lip.

9. The sealing device according to claim 1 or 7, comprising a plurality of the lips, wherein the lips are arranged radially.

10. The sealing device according to claim 1, wherein the slinger has a fitting portion which is a cylindrical portion extending along the axis and an annular portion which is an annular portion extending radially from one end of the fitting portion, and the lip is configured to contact the annular portion of the slinger.

11. The sealing device according to claim 1, which is a hub seal used in a hub bearing.

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