sealing device

Abstract

To provide a sealing device that can improve axial assembly and sealing performance. [Solution] A sealing device 10 is installed between a first member 2 and a second member 3 that rotate relative to each other via rolling elements 4, and comprises an annular core body 11 and an elastic part 12 made of an elastic material fixed to the core body, wherein the elastic part has a mounting portion 13 that fits into a concave circumferential groove 2b provided in the circumferential direction of the opposing surface 2a of the first member facing the second member, and a lip portion 14 that extends toward the opposing surface 3a of the second member facing the first member, and the mounting portion has a projection 13b that elastically contacts the first groove wall 2bb on one axial side of the circumferential groove, and an elastic contact portion 13c that elastically contacts the second groove wall 2bc on the other axial side of the circumferential groove.

Description

Technical Field

[0001] The present invention relates to a sealing device that is mounted between a first member and a second member that rotate relative to each other via rolling elements, and includes an annular core and an elastic portion made of an elastic material and fixed to the core.

Background Art

[0002] Conventionally, a sealing device that is attached to a circumferential groove provided in a first member and seals an annular space between the first member and the second member is known. For example, in Patent Document 1 below, there is disclosed a sealing plate 1 with a core metal 1B provided with an elastic body 1A that is attached to a circumferential groove formed in the circumferential direction of the opposing surface of the inner ring 5 facing the outer ring 3 and that slidably contacts the opposing surface of the outer ring 3 facing the inner ring 5.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the case of the device disclosed in Patent Document 1 above, when the sealing plate 1 is fixed to the circumferential groove 9, there is a gap between the elastic fixing portion and the inner flat surface 34 of the peripheral protrusion, and the circumferential wall on the outer diameter side of the circumferential groove 9 is not sealed. Therefore, there is a concern about the axial sealing performance, and there is also a concern that it is likely to come off axially in terms of assembly. In addition, in the device disclosed in Patent Document 1 above, mud and water are likely to accumulate in the gap between the elastic fixing portion and the inner flat surface 34 of the peripheral protrusion, which may cause rusting. Furthermore, since the circumferential groove formed in the outer ring has dimensional tolerances, the above-described sealing device needs to be designed for sealing in consideration of the dimensional tolerances of the circumferential groove.

[0005] This invention has been made in view of the above circumstances, and aims to provide a sealing device that can improve axial assembly and sealing performance. [Means for solving the problem]

[0006] To achieve the above objective, the sealing device configuration 1 of the present invention is installed between a first member and a second member that rotate relative to each other via rolling elements, and comprises an annular core and an elastic part made of an elastic material fixed to the core, wherein the elastic part has a mounting portion that fits into a concave circumferential groove provided in the circumferential direction on the opposing surface of the first member facing the second member, and a lip portion that extends toward the opposing surface of the second member facing the first member, and the mounting portion has a projection that elastically contacts the first groove wall on one axial side of the circumferential groove and an elastic contact portion that elastically contacts the second groove wall on the other axial side of the circumferential groove.

[0007] The following description of embodiments reveals that the sealing device according to the present invention may have the following dependent configurations. <Configuration 2> In configuration 1, the projection is formed to protrude from other parts toward the rolling element side, and the distance from the tip of the projection to the other end of the elastic contact portion on the axial side may be greater than the axial groove width dimension of the circumferential groove. <Structure 3> In configuration 1 or configuration 2, the core body has a core body cylindrical portion to which the mounting portion is fixed, and a core body disc portion extending inward from the other axial end of the core body cylindrical portion, and at least a part of the projection may be provided so as to overlap the core body cylindrical portion in the axial direction. <Structure 4> In any one of configurations 1 to 3, the elastic contact portion may have a deformable portion that elastically deforms and makes elastic contact with the corner on the other axial side of the second groove wall. [Effects of the Invention]

[0008] Since the sealing device of the present invention has the above-described configuration, it is possible to improve axial assembly and sealing performance. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic longitudinal cross-sectional view showing an example of a bearing device to which a sealing device according to one embodiment of the present invention is attached. [Figure 2] (a) is an enlarged view of section X in Figure 1, which is a schematic longitudinal cross-sectional view and an enlarged view of its main parts illustrating the sealing device, and (b) is a schematic cross-sectional view illustrating the circumferential groove into which the sealing device is assembled. [Figure 3] This is a schematic longitudinal cross-sectional view illustrating a modified example of the sealing device. [Modes for carrying out the invention]

[0010] Hereinafter, an example of a sealing device according to this embodiment will be described with reference to the drawings. Note that in some figures, some of the detailed reference numerals used in other figures have been omitted. Figure 1 shows an example of a bearing device to which the sealing device is mounted, Figure 2(a) shows an example of a sealing device according to one embodiment, and Figure 2(b) shows an example of a circumferential groove of the first member.

[0011] The sealing device 10 according to this embodiment is mounted between a first member 2 and a second member 3 that rotate relative to each other via rolling elements 4. The sealing device 10 comprises an annular core body 11 and an elastic part 12 made of an elastic material fixed to the core body 11. The elastic part 12 has a mounting portion 13 that fits into a concave circumferential groove 2b provided in the circumferential direction of the opposing surface 2a of the first member 2 facing the second member 3, and a lip portion 14 that extends toward the opposing surface 3a of the second member 3 facing the first member 2. The mounting portion 13 has a projection 13b that elastically contacts the first groove wall 2bb on one axial side of the circumferential groove 2b, and an elastic contact portion 13c that elastically contacts the second groove wall 2bc on the other axial side of the circumferential groove 2b. Hereinafter, a sealing device 10 used as a flat seal will be described as a specific example of its configuration. In the following explanation, the rolling element 4 side will be referred to as one axial side, the external space side as the other axial side, the inner diameter side as the inward side, and the outer diameter side as the outward side.

[0012] As shown in Figure 1, the bearing device 1 has annular first member 2 and second member 3 that rotate coaxially relative to each other around the axis L of the shaft 5. In the illustrated example, the first member 2 is provided as an outer member positioned outside (outer diameter side) of the second member 3, and the second member 3 is provided as an inner member that fits onto the shaft 5. The bearing device 1 has a single row of rolling elements 4 (balls in the illustrated example) in the annular space S between the first member 2 and the second member 3. The rolling elements 4 are interposed between the first member 2 and the second member 3 so as to be able to roll while being held by a retainer (not shown). The bearing device 1 may have the first member 2 as the fixed side and the second member 3 as the rotating side member, or the first member 2 as the rotating side and the second member 3 as the fixed side member, but in this embodiment, the case where the first member 2 is the fixed side and the second member 3 is the rotating side member will be described.

[0013] Sealing devices 10, 10 are installed at both axial ends between the first member 2 and the second member 3 that constitute the bearing device 1. Thus, both ends of the annular space S of the bearing device 1 are sealed by these sealing devices 10, 10, preventing the intrusion of foreign matter such as muddy water into the annular space S and preventing the leakage of lubricant (grease, etc.) filled in the annular space S to the outside. The sealing device 10 is an annular member that is aligned with the circumferential direction of the first member 2 and the second member 3. When the sealing device 10 is installed in the bearing device 1, its other axial side (external space side) is positioned substantially on the same line as the other axial side of the first member 2 and the second member 3. In the following description, the sealing device 10 installed on the right side in Figure 1 will be used as an example.

[0014] As shown in Figures 2(a) and 2(b), a concave circumferential groove 2b opening inward (towards the inner diameter) is provided at the axial end of the first member 2. The circumferential groove 2b is formed around the entire circumference of the first member 2 and has a groove bottom 2ba, a first groove wall 2bb, and a second groove wall 2bc. The groove bottom 2ba is formed in a concave curved shape when viewed in cross-section, and the first groove wall 2bb is provided so as to extend inward from one axial end of the groove bottom 2ba. The second groove wall 2bc is provided so as it extends inward from the other axial end of the groove bottom 2ba, it is inclined toward the other axial side.

[0015] As shown in Figure 2(a), a stepped portion 3b is provided at the axial end of the second member 3, opening to the external space side (the other axial side). The stepped portion 3b is formed around the entire circumference of the second member 3 and has a bottom portion 3ba which is the opposing surface 3a facing the first member 2, and a wall portion 3bb which is provided so as to extend outward from one axial end of the bottom portion 3ba.

[0016] The core body 11 is formed in an annular shape along the circumferential direction of the first member 2 and the second member 3, and may be formed by press-forming a steel plate such as SPCC or SUS, or it may be formed from synthetic resin or the like. As shown in Figure 2(a), the core body 11 has a core body cylindrical portion 11a to which the mounting portion 13 is fixed, a core body disc portion 11b extending inward from the other axial end 11aa of the core body cylindrical portion 11a, and a bent portion 11c that is bent to one axial side from the inner end 11ba of the core body disc portion 11b. In the illustrated example, the bent portion 11c is formed to have a smaller axial dimension than the core body cylindrical portion 11a.

[0017] The elastic part 12 is made of an elastic material such as rubber or elastomer and is fixed and integral with the core body 11. As shown in Figure 2(a), the elastic part 12 has a mounting part 13 that fits into the circumferential groove 2b and a lip part 14 that extends toward the opposing surface 3a of the second member 3. In the illustrated example, the elastic part 12 is fixed so as to cover the other axial side of the core body disc part 11b, the entire core body cylindrical part 11a, and the end face on one axial side of the bent part 11c.

[0018] The mounting portion 13 is provided as a portion outside the elastic portion 12. The mounting portion 13 includes a base portion 13a fixed to the core cylindrical portion 11a, a protrusion portion 13b elastically contacting the first groove wall 2bb on one axial side of the circumferential groove 2b, an inclined portion 13d provided outside the protrusion portion 13b and inclined toward the other axial side as it goes outward, an elastic contact portion 13c elastically contacting the second groove wall 2bc on the other axial side of the circumferential groove 2b, and a shoulder portion 13e formed to protrude stepwise from the end portion 13ca on the other axial side of the elastic contact portion 13c toward the other axial side. The base portion 13a has an opposing surface 13aa opposing the first groove wall 2bb of the circumferential groove 2b, and this opposing surface 13aa is formed in a flat surface shape so as to contact along the first groove wall 2bb when mounted on the bearing device 1. The protrusion portion 13b is formed to protrude more than other portions toward the rolling element 4 side (one axial side), and protrudes in a convex curved shape (substantially semi-circular shape) in a cross-sectional view from the opposing surface 13aa. The protrusion portion 13b may be formed in a continuous annular shape along the circumferential direction or may be formed intermittently along the circumferential direction. The dimension W2 from the tip (the most protruding portion) of the protrusion portion 13b to the end portion 13ca on the other axial side of the elastic contact portion 13c is made larger than the groove width dimension W1 in the axial direction of the circumferential groove 2b. With such a configuration, when the mounting portion 13 is assembled into the circumferential groove 2b, the protrusion portion 13b is pressed toward the rolling element 4 side and is mounted in an elastically deformed state, so that the mounting portion 13 is firmly assembled into the circumferential groove 2b and the sealing performance can be improved. Also, as shown in FIG. 2(a), it is preferable that at least a part of the protrusion portion 13b is provided so as to overlap the core cylindrical portion 11a in the axial direction. According to such a configuration, the protrusion portion 13b is easily compressed in the axial direction by the core cylindrical portion 11a. In the illustrated example, the inner portion of the protrusion portion 13b is formed so as to overlap the outer portion of the core cylindrical portion 11a in the axial direction when viewed axially.

[0019] The elastic contact portion 13c is provided outside the base portion 13a. In the illustrated example, the elastic contact portion 13c is formed to be curved so as to bulge toward the other side in the axial direction. The elastic contact portion 13c has a deformed portion 13cb that elastically deforms and elastically contacts the corner portion 2bd on the other side in the axial direction of the second groove wall 2bc. According to the above configuration, since the elastic contact portion 13c firmly elastically contacts the corner portion 2bd, the sealing property of the corner portion 2bd that is likely to be attacked by muddy water or the like can be enhanced. Further, if the distance from the deformed portion 13cb to the end portion 13ca on the other side in the axial direction of the elastic contact portion 13c is made as short as possible, and a stepped shoulder portion 13e is formed from the end portion 13ca, the space formed by the deformed portion 13cb, the shoulder portion 13e, and the corner portion 2bd can be reduced. Therefore, by reducing the gap where muddy water or the like is likely to accumulate due to the space between the shoulder portion 13e and the corner portion 2bd, the places where muddy water or the like accumulates can be reduced, and the occurrence of rust can be suppressed. In the illustrated example, a vicinity portion of the end portion 13ca on the other side in the axial direction of the elastic contact portion 13c is provided as the deformed portion 13cb. With such a configuration, when assembling the attachment portion 13 to the circumferential groove 2b, the protrusion portion 13b can be smoothly assembled into the circumferential groove 2b while pressing the elastic contact portion 13c against the second groove wall 2bc and pressing the protrusion portion 13b against the first groove wall 2bb of the circumferential groove 2b. After assembly to the circumferential groove 2b, a force to restore acts on the elastically deformed protrusion portion 13b and the contact surface, making it easier for the deformed portion 13cb to elastically contact the corner portion 2bd.

[0020] The lip portion 14 is provided as a portion inside the elastic portion 12. In the illustrated example, the lip portion 14 has a lip base portion 14a that is fixed to the end portion 11ca of the bent portion 11c and is the root portion (starting end) of the lip piece 14b, and a lip piece 14b that is formed to be inclined toward the other side in the axial direction as it extends inward from the lip base portion 14a. The lip piece 14b is formed to contact the bottom surface 3ba, which is the opposing surface of the second member 3, in a state where the attachment portion 13 is fitted into the circumferential groove 2b of the first member 2. Further, the lip base portion 14a is formed to be non-contact with a wall portion 3bb that is formed to rise from the end portion on one side in the axial direction of the opposing surface 3a in a state of being assembled to the circumferential groove 2b.

[0021] With the above-described sealing device 10, the mounting portion 13 has a projection 13b that elastically contacts the first groove wall 2bb of the circumferential groove 2b, and an elastic contact portion 13c that elastically contacts the second groove wall 2bc of the circumferential groove 2b, so that each groove wall in the axial direction of the circumferential groove 2b can be sealed. Therefore, the radial direction between the opposing surfaces 2a and 3a is sealed by the mounting portion 13 and the lip portion 14, and the above configuration improves axial assembly, making it less likely to come loose and improving axial sealing performance. Furthermore, with the above configuration, dimensional tolerances of the circumferential groove 2b occur not only in the radial direction but also in the axial direction, making dimensional control of the circumferential groove 2b easier.

[0022] Next, a modified example, the sealing device 10A, will be described with reference to Figure 3. Note that the configurations and effects common to the sealing device 10 described above will be omitted or briefly explained. The sealing device 10A shown in Figure 3 differs from the above-described configuration in the configuration of the elastic contact portion 13c (deformable portion 13cb), while the configuration of the other parts is the same as in the example in Figure 2. In the illustrated example, the elastic contact portion 13c is formed as a flat inclined surface that slopes toward one side in the axial direction as the other side in the axial direction extends outward. In other words, the cross-sectional shape is triangular formed by the elastic contact portion 13c and the inclined portion 13d, and the approximately central part of the elastic contact portion 13c becomes the deformable portion 13cb that elastically contacts the corner portion 2bd of the second groove wall 2bc. Even with this configuration, the same effects as in the above embodiment are achieved.

[0023] The sealing devices 10 and 10A are not limited to the configurations described above. For example, the core body 11 may not have a bent portion 11c. The projection 13b may have a cross-sectional shape other than a semicircle, for example, a roughly triangular shape. Also, the projection 13b may be provided so as not to overlap the core body cylindrical portion 11a when viewed in the axial direction, or it may be provided so that the entire projection overlaps the core body cylindrical portion 11a when viewed in the axial direction. Furthermore, the configuration and shape of the lip portion 14 are not limited to the illustrated example, and there may be multiple lip portions, and they may or may not slide against the opposing surface 3a.

[0024] Furthermore, the bearing device 1 to which the sealing devices 10, 10A are attached is not limited to the above-described configuration. For example, the circumferential groove 2b may have a groove bottom 2ba that is flat in cross-sectional view. Also, the second member 3 may not have a stepped portion 3b, and may have a groove such as the circumferential groove 2b formed in the first member 2. In addition, the bearing device 1 may be configured with the inner member being the first member 2 and the outer member being the second member 3, and the mounting portion 13 may be fitted into the circumferential groove 2b of the inner member, the first member 2. [Explanation of Symbols]

[0025] 2. First Member 2a Opposite surface 2b Circumferential groove 2bb No. 1 trench wall 2bc 2nd groove wall 3. Second Member 3a Opposite surface 4 Rolling elements 10,10A sealing device 11 Core body 11a Core cylindrical part 11b Core disc section 12 Elastic part 13 Mounting part 13b Protrusion 13c Ballistic contact part 13cb Deformed part 14 Lip section W1 Groove width dimension W2 Dimension from the tip of the projection to the other end of the contact point in the axial direction

Claims

1. A sealing device is installed between a first member and a second member that rotate relative to each other via rolling elements, and comprises an annular core and an elastic part made of an elastic material fixed to the core, The elastic portion has a mounting portion that is fitted into a concave circumferential groove provided in the circumferential direction of the opposing surface of the first member that faces the second member, and a lip portion that extends toward the opposing surface of the second member that faces the first member. The sealing device is characterized in that the mounting portion has a projection that elastically contacts the first groove wall on one axial side of the circumferential groove, and an elastic contact portion that elastically contacts the second groove wall on the other axial side of the circumferential groove.

2. In claim 1, The aforementioned projection is formed to protrude from other parts toward the rolling element side, A sealing device characterized in that the distance from the tip of the projection to the other end of the elastic contact portion on the axial side is greater than the axial groove width dimension of the circumferential groove.

3. In claim 1 or claim 2, The core body has a cylindrical core body portion to which the mounting portion is fixed, and a disc core body portion extending inward from the other end of the cylindrical core body portion on the axial side, A sealing device characterized in that at least a portion of the projection is provided so as to overlap the core cylindrical portion in the axial direction.

4. In claim 1 or claim 2, The sealing device is characterized in that the elastic contact portion has a deformable portion that elastically deforms and makes elastic contact with the corner on the other axial side of the second groove wall.

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