sealing member

Abstract

To provide a coreless sealing member that can be stably mounted in the desired position while maintaining airtightness. [Solution] A sealing member 10 is installed in a concave annular groove 5 that seals the space between the end faces 4a, 4a of a pair of inner ring members 4, 4 that abut each other in the axial direction, and is partitioned by stepped portions 4b, 4b provided at the outer peripheral corners of each of the end faces. The sealing member 10 comprises an annular main body portion 11 arranged to straddle the space between the end faces within the annular groove, a pair of positioning portions 12, 12 extending from the main body portion in both axial directions and elastically contacting or approaching the side wall surfaces 4ba of the stepped portions, a first sealing portion 13 extending from the main body portion to elastically contact the first bottom surface 4bb of the stepped portion of one of the pair of inner ring members, and a second sealing portion 14 extending from the main body portion to elastically contact the second bottom surface 4bc of the stepped portion of the other inner ring member of the pair, and is made solely of an elastic material.

Description

Technical Field

[0001] The present invention relates to a seal member for sealing between end faces that abut against each other in the axial direction in a pair of inner ring members that constitute the inner member among an outer member and an inner member that rotate coaxially relative to each other.

Background Art

[0002] Conventionally, a bearing device including an inner member configured by abutting a plurality of inner ring members is known. In such a bearing device, there is a concern that the lubricant filled in the bearing device may leak to the outside from between the end faces where the inner ring members abut against each other. In Patent Document 1 below, a sealing device for a roll neck bearing arranged so as to straddle a circumferential step portion formed in two inner rings is disclosed. In this sealing device, an elastic seal is baked and fixed to a mandrel, a radial lip portion provided on the elastic seal is slidably contacted with the outer peripheral surface of the circumferential step portion, and a side lip portion is slidably contacted with the side surface of the circumferential step portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Such a seal member can be stably assembled at a desired position by including a mandrel, but the sealing device described in Patent Document 1 above required baking and fixing an elastic seal.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a coreless seal member that can be stably mounted at a desired position while maintaining sealing performance.

Means for Solving the Problems

[0006] To achieve the above objective, the present invention provides a sealing member that seals the space between end faces that abut each other in the axial direction in a pair of inner ring members constituting the inner member of an outer member and an inner member that rotate coaxially relative to each other, and is fitted into a concave annular groove partitioned by stepped portions provided at the outer peripheral corners of each of the end faces, comprising: an annular main body portion disposed to straddle the space between the end faces in the annular groove; a pair of positioning portions extending from the main body portion in both axial directions and elastically contacting or approaching the side wall surfaces of the stepped portions; a first sealing portion extending from the main body portion to elastically contact the first bottom surface of the stepped portion of one of the pair of inner ring members; and a second sealing portion extending from the main body portion to elastically contact the second bottom surface of the stepped portion of the other inner ring member of the pair of inner ring members, and is characterized by being composed solely of an elastic material. [Effects of the Invention]

[0007] Because the sealing member of the present invention has the above-described configuration, it is a coreless member that can be stably mounted in the desired position while maintaining airtightness. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic longitudinal cross-sectional view showing an example of a bearing device to which a sealing member according to one embodiment of the present invention is assembled. [Figure 2] (a) is a schematic enlarged view of section X in Figure 1, which is a schematic longitudinal cross-sectional view illustrating the sealing member according to the same embodiment. (b) is a schematic cross-sectional view illustrating the sealing member according to the same embodiment. [Figure 3] (a) to (c) are schematic cross-sectional views showing the assembly procedure of the sealing member according to the same embodiment. [Figure 4] (a) and (b) are schematic cross-sectional views illustrating a sealing member according to one modified example of the same embodiment. [Modes for carrying out the invention]

[0009] An example of a sealing member according to this embodiment will be described below with reference to the drawings. Note that in some of the drawings, some of the detailed reference numerals used in other drawings have been omitted. Also, in the drawings, the second sealing portion shown by the dashed line represents the shape in its natural state before elastic deformation. Furthermore, in the following description, one axial side will be referred to as the wheel side, and the other axial side as the vehicle body side.

[0010] The sealing member 10 seals the space between the end faces 4a, 4a (see Figures 1 and 2(a)) that abut each other axially in a pair of inner ring members 4, 4 that constitute the inner member 3 of the outer member 2 and inner member 3, which rotate coaxially relative to each other. The sealing member 10 is fitted into a concave annular groove 5 that is demarcated by stepped portions 4b, 4b provided at the outer peripheral corners of the respective end faces 4a, 4a. The sealing member 10 comprises an annular main body portion 11 that straddles the space between the end faces 4a, 4a within the annular groove 5, and a pair of positioning portions 12, 12 that extend from the main body portion 11 on both axial sides and elastically contact or approach the side wall surfaces 4ba of the stepped portions 4b. The sealing member 10 includes a first sealing portion 13 that extends from the main body portion 11 so as to elastically contact the first bottom surface 4bb of the stepped portion 4b of one of the pair of inner ring members 4, 4. Furthermore, the sealing member 10 includes a second sealing portion 14 that extends from the main body portion 11 so as to elastically contact the second bottom surface 4bc of the stepped portion 4b of the other inner ring member 4 of the pair of inner ring members 4, 4. The sealing member 10 is composed solely of an elastic material. A detailed explanation follows below. In the following explanation, one inner ring member 4 will be referred to as the inner ring member 4 on the wheel side, and the other inner ring member 4 will be referred to as the inner ring member 4 on the vehicle body side.

[0011] Figure 1 schematically shows an example of a vehicle bearing device 20 in which a bearing device 1 comprising an outer member 2 and an inner member 3 is installed. The vehicle bearing device 20 is used in vehicles larger than ordinary automobiles, such as trucks and buses. The vehicle bearing device 20 comprises an axle housing 23 through which a fully floating axle shaft 21 is inserted, a bearing device 1 which is a rolling bearing having a plurality of tapered rollers 6, 6, and a hub wheel 26 to which the wheel is connected. The hub wheel 26 is connected to the flange 22 of the axle 21 by bolts 27, and power from the differential gear is transmitted to the hub wheel 26 via the axle, causing the wheel to rotate. The bearing device 1, which rotatably supports the hub wheel 26, is fitted inside the hub wheel 26. The outer circumferential surface of the outer member 2 of the bearing device 1 is fitted inside the hub wheel 26.

[0012] The bearing device 1 comprises an outer member 2, an inner member 3, multiple rows of tapered rollers 6, 6 arranged as rolling elements, and cages 7, 7 that hold the tapered rollers 6, 6. The inner member 3 is composed of a pair of inner ring members 4, 4 arranged in the axial direction. The multiple rows of tapered rollers 6, 6 are interposed in the cages 7, 7 so as to be able to roll on the raceway surface 2a of the outer member 2 and the raceway surface 3a of the inner member 3. An annular space S is provided around the entire circumference between the outer member 2 and the inner member 3. The bearing device 1 is fitted with sealing devices 8, 8 on both axial sides to seal the space between the outer member 2 and the inner member 3. The annular space S is sealed by providing the sealing devices 8, 8 at the vehicle body side end and the wheel side end of the bearing device 1, respectively.

[0013] As shown in Figure 1, the bearing device 1 is fitted inside the hub ring 26 and also fitted outside the axle tube step portion 24 formed at one end of the outer circumferential surface of the axle tube 23. Specifically, the bearing device 1 is fitted outside the axle tube step portion 24 such that the body-side end face of the inner member 3 (body-side inner ring member 4) abuts against the side wall surface of the axle tube step portion 24. An annular fixing member 25 fitted outside the axle tube step portion 24 abuts against the wheel-side end face of the inner member 3. In the case of a fully floating type as shown in Figure 1, the wheel is attached to the axle tube 23 by the hub ring 26 and the bearing device 1. As a result, the load of the automobile is supported by the axle tube 23, so the load applied to the axle 21 can be distributed, and the axle 21 is designed to be removable regardless of the wheel. Therefore, when inspecting the axle 21 for twisting or cracks, the axle 21 can be removed by unscrewing the bolts 27. Furthermore, when replacing or inspecting the bearing device 1, the structure allows the bearing device 1 to be removed from the axle tube 23 by removing the bolts 27 and the fixing member 25. In a vehicle bearing device 20 with this structure, differential oil flows to the flange 22 side through the gap between the outer circumference of the axle 21 and the inner circumference of the axle tube 23 due to centrifugal force acting when the vehicle turns, so the sealing devices 8,8 suppress the intrusion of differential oil into the annular space S of the bearing device 1.

[0014] As shown in Figure 2(a), each of the pair of inner ring members 4, 4 is provided with a stepped portion 4b at the outer corner of the end that abuts against each other. Specifically, the inner ring member 4 on the wheel side is provided with a stepped portion 4b at the outer corner of the end on the vehicle body side, and the inner ring member 4 on the vehicle body side is provided with a stepped portion 4b at the outer corner of the end on the wheel side. The stepped portion 4b is provided around the entire circumference of the inner ring member 4, and is formed in an inward corner shape on the inner diameter side. The stepped portion 4b of the inner ring member 4 on the wheel side comprises a first bottom surface 4bb and a side wall surface 4ba formed to rise from the wheel side end of the first bottom surface 4bb toward the outer diameter side. Similarly, the inner ring member 4 on the vehicle body side comprises a second bottom surface 4bc and a side wall surface 4ba formed to rise from the vehicle body side end of the second bottom surface 4bc. Then, by bringing together the end faces 4a, 4a of the pair of inner ring members 4, 4, each equipped with this stepped portion 4b, a concave annular groove 5 is formed.

[0015] The sealing member 10 is positioned within the annular groove 5 so as to straddle the end faces 4a, 4a, and is formed in an annular shape along the circumferential direction of the annular groove 5. The sealing member 10 has a flat outer surface 10a formed by the outer surface of the main body portion 11 and the outer surfaces of the pair of positioning portions 12, 12, and the height dimension of the sealing member 10 is set to fit within the annular groove 5. That is, when the sealing member 10 is installed in the annular groove 5, the outer surface 10a is formed so as not to protrude outward from the opening of the annular groove 5. The elastic material constituting such a sealing member 10 may be, for example, NBR, H-NBR, ACM, AEM, FKM, etc. In the illustrated example, the sealing member 10 is formed with an axial dimension that is approximately the same as the axial dimension of the annular groove 5.

[0016] The annular main body portion 11 is formed to follow the circumferential direction of the annular groove 5 when the sealing member 10 is installed in the annular groove 5, and the main body portion 11 is formed to be of an appropriate size and shape that allows it to straddle the end faces 4a, 4a of the pair of inner ring members 4, 4 when installed in the annular groove 5. In the illustrated example, the main body portion 11 is formed in a roughly rectangular shape in a longitudinal cross-sectional view, with the axial dimension being larger than the radial dimension.

[0017] The pair of positioning portions 12, 12 are formed symmetrically so as to protrude axially from both axial ends of the main body portion 11, and are formed in an annular shape continuously along the circumferential direction of the main body portion 11. In the illustrated example, the distance between the protruding (axial) tips 12a, 12a of the pair of positioning portions 12, 12 is formed to be approximately the same as the axial dimension of the annular groove 5, and an example is shown where they elastically contact the side wall surface 4ba of the stepped portion 4b. However, this elastic contact does not have to be strong; it may be merely a light contact or even close (non-contact). The positioning portions 12 are not limited to being formed continuously along the circumferential direction, but may be formed intermittently along the circumferential direction of the main body portion 11, for example. Also, in the illustrated example, the axial dimension of the positioning portion 12 is smaller than that of the main body portion 11, and the outer circumferential surface of the positioning portion 12 is provided to be flush with the outer circumferential surface of the main body portion 11, forming part of the outer circumferential surface 10a of the sealing member 10. Furthermore, if, as shown in the example figure, the sealing member 10 is positioned within the annular groove 5, and the pair of positioning portions 12, 12 are formed such that their protruding tips 12a each abut against the side wall surface 4ba of the stepped portion 4b, then, compared to a configuration in which the protruding tips 12a of the positioning portions 12 are close to the side wall surface 4ba of the stepped portion 4b without abutting against it, the sealing performance between the end faces 4a, 4a of the annular groove 5 can be improved more effectively.

[0018] The first sealing portion 13 and the second sealing portion 14 are provided on the inner circumference of the main body portion 11, respectively, spaced apart from each other in the axial direction, and are formed in an asymmetrical shape. The first sealing portion 13 and the second sealing portion 14 are formed in an annular shape that is continuously formed along the circumferential direction of the main body portion 11, as shown in Figure 2(b). When the sealing member 10 is installed in the annular groove 5, the first sealing portion 13 is provided so as not to contact the first bottom surface 4bb, while the second sealing portion 14 is provided so as not to contact the second bottom surface 4bc. Furthermore, the first sealing portion 13 and the second sealing portion 14 are formed in a shape that gradually tapers toward the tip and has an overlap to elastically contact. With this configuration, the tapered shape makes it easy to deform and easy to install the sealing member 10. Also, because it has an overlap, the sealing performance can be improved.

[0019] The first seal portion 13 is provided on the wheel side of the main body portion 11 and extends inward from the main body portion 11. The first seal portion 13 is formed in a substantially triangular shape that tapers toward the inner diameter end portion 13a, which is the tip on the inner diameter side, when viewed in a longitudinal section, and the inner diameter end portion 13a elastically contacts the first bottom surface 4bb when the seal member 10 is installed in the annular groove 5. In the illustrated example, the first seal portion 13 has inclined surfaces that tilt toward the axial center of the first seal portion 13 as both axial sides 13b, 13b extend toward the inner diameter side.

[0020] The second seal portion 14 is provided on the vehicle body side of the main body portion 11. The second seal portion 14 extends from the main body portion 11 toward the inner diameter side, and is formed so as to incline toward the first seal portion 13 side as it extends toward the inner diameter side. In the illustrated example, in the natural state before the second seal portion 14 is mounted in the annular groove 5, the inner diameter side end portion 14a, which is the tip of the second seal portion 14, is formed so as to be located on the inner diameter side with respect to the inner diameter side end portion 13a of the first seal portion 13. Further, the second seal portion 14 is formed to be inclined along the insertion direction when the other inner ring member 4 is assembled. With such a configuration, as shown in FIGS. 3(b) and 3(c), when the inner ring member 4 on the vehicle body side is assembled after the seal member 10, the second seal portion 14 elastically deforms along the insertion direction of the inner ring member 4 on the vehicle body side, making it easier to assemble the inner ring member 4 on the vehicle body side.

[0021] Next, an example of the method of assembling the seal member 10 will be described while referring to FIG. 3. As shown in FIG. 3(a), in a state before the end faces 4a, 4a of the pair of inner ring members 4, 4 abut against each other, the seal member 10 is assembled from the vehicle body side toward the step portion 4b of the inner ring member 4 on the wheel side. As shown in FIG. 3(b), the seal member 10 is mounted on the inner ring member 4 on the wheel side so that the positioning portion 12 on the wheel side abuts against the side wall surface 4ba of the step portion 4b. Thereby, the axial position of the seal member 10 is positioned. In this state, the inner diameter side end portion 13a of the first seal portion 13 elastically abuts against the first bottom surface 4bb. In this state, the inner diameter side end portion 14a of the second seal portion 14 is located on the inner diameter side with respect to the first bottom surface 4bb. Then, as shown in FIG. 3(c), when the inner ring member 4 on the vehicle body side is assembled, the second seal portion 14 contacts the inner ring member 4 on the vehicle body side and elastically deforms along the insertion direction of the inner ring member 4 on the vehicle body side, and the inner ring member 4 on the vehicle body side is assembled in a state where the second seal portion 14 contacts the second bottom surface 4bc. <000​The seal member 10 according to this embodiment is composed only of an elastic material, so that compared with a configuration having a core metal, weight reduction, reduction of manufacturing costs, and shortening of manufacturing time by reducing steps such as a step of fixing the core metal and the elastic material can be achieved. Further, by providing positioning portions on both axial sides of the main body portion 11 and contacting or approaching the side wall surfaces 4ba, 4ba of the stepped portion 4b, axial positioning in the annular groove 5 can be appropriately performed, and stable mounting can be achieved. Furthermore, by providing a first seal portion 13 elastically contacting the first bottom surface 4bb and a second seal portion 14 elastically contacting the second bottom surface 4bc, the end surfaces 4a, 4a can be sealed.

[0023] Next, a seal member according to a modified example will be described with reference to FIG. 4. In addition, the description of the configuration and effects of the parts common to the example described above will be omitted or briefly described. In the seal member 10A shown in FIG. 4(a), a protrusion 15 is provided between the first seal portion 13 and the second seal portion 14, which protrudes from the main body portion 11 toward the inner diameter side and has a height dimension lower than those of the first seal portion 13 and the second seal portion 14. With such a configuration, even if the seal member 10A is tilted when being assembled to the inner ring members 4, 4, the protrusion 15 contacts the first bottom surface 4bb or the second bottom surface 4bc of the stepped portion 4b, thereby suppressing the tilting of the seal member 10A. Therefore, the seal member 10A that is easy to assemble can be obtained. The height dimension of the protrusion 15 is a dimension along the radial direction of the seal member 10A.

[0024] In the illustrated example, the seal member 10A is provided with two projections 15 spaced apart in the axial direction. The projections 15 are formed in an annular shape that is continuously formed along the circumferential direction of the main body 11. In a vertical cross-sectional view, the projections 15 are formed in a triangular shape that tapers toward the inner diameter. The height dimension of the projections 15 should be such that, as shown in Figure 4(b), when the seal member 10A is tilted while assembled to only one inner ring member 4 (the inner ring member 4 on the wheel side in the illustrated example), the projections 15 contact the bottom surface of the stepped portion 4b (the first bottom surface 4bb in the illustrated example). In the illustrated example, the projections 15 are configured not to contact the first bottom surface 4bb or the second bottom surface 4bc of the stepped portion 4b when the seal member 10 is mounted in the annular groove 5, but the inner diameter side end may contact it. Furthermore, the number of projections 15 provided on the seal member 10A is not limited to two; there may be one or three or more. Furthermore, the projection 15 is not limited to having a triangular shape in its vertical cross-sectional view; for example, it may be rectangular or semicircular. Also, the projection 15 may have a shape that spans between the end faces 4a, 4a. In addition, the projection 15 may be provided intermittently along the circumferential direction of the main body 11.

[0025] The sealing members 10 and 10A are not limited to the configuration described above. For example, the entire sealing members 10 and 10A may be formed in a line-symmetrical manner with respect to the axial center line L as the axis of symmetry in a cross-sectional view as shown in Figure 2(b). Also, as described above, the dimension between the protruding tips 12a, 12a of the pair of positioning parts 12, 12 may be formed to be slightly larger than the axial dimension of the annular groove 5, so as to firmly elastically contact the side wall surfaces 4ba, 4ba of the stepped part 4b. Alternatively, the dimension between the protruding tips 12a, 12a of the pair of positioning parts 12, 12 may be formed to be slightly smaller than the axial dimension of the annular groove 5, so as not to elastically contact the side wall surfaces 4ba, 4ba of the stepped part 4b. Furthermore, the first sealing part 13 and the second sealing part 14 are not limited to a shape that gradually tapers towards the tip, and may be formed in a rectangular shape in a longitudinal cross-sectional view, for example. Moreover, the annular groove 5 into which the sealing members 10 and 10A are mounted is not limited to the configuration described above. For example, the stepped portion 4b may have side wall surfaces 4ba, 4ba whose radial dimensions are larger than those of the bottom surface (first bottom surface 4bb and second bottom surface 4bc). [Explanation of symbols]

[0026] 2 Outer member 3. Inner member 4 Inner ring member 4a End face 4b Stepped section 4ba side wall 4bb 1st bottom 4bc 2nd bottom 5. Ring groove 10,10A sealing member 11 Main body 12 Positioning section 13. First seal section 14. Second seal section 15. Protrusion

Claims

1. A sealing member is provided for a pair of inner ring members constituting the inner member of an outer member and an inner member that rotate relatively coaxially, sealing the space between end faces that abut each other in the axial direction, and being mounted in a concave annular groove defined by stepped portions provided at the outer circumferential corners of each of the end faces, A sealing member comprising: an annular main body portion disposed within the annular groove so as to straddle the end faces; a pair of positioning portions extending axially from the main body portion on both sides and elastically contacting or approaching the side wall surface of the stepped portion; a first sealing portion extending from the main body portion so as to elastically contact the first bottom surface of the stepped portion of one of the pair of inner ring members; and a second sealing portion extending from the main body portion so as to elastically contact the second bottom surface of the stepped portion of the other inner ring member of the pair of inner ring members, wherein the sealing member is made solely of an elastic material.

2. In claim 1, The sealing member is characterized in that the first sealing portion and / or the second sealing portion are shaped to gradually taper toward the tip and have an overlap that allows for elastic contact.

3. In claim 1 or claim 2, A sealing member characterized in that a projection is provided between the first sealing portion and the second sealing portion, which protrudes inward from the main body portion and has a lower height dimension than the first sealing portion and the second sealing portion.

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