Rolling bearing

Abstract

To provide a rolling bearing capable of preventing warpage of a seal member.SOLUTION: An outer ring 100 includes a raceway groove 101 on which a ball 130 rolls, a peripheral groove 110 provided on the axial outer side relative to the raceway groove 101, an outer shoulder 114 provided on the axial outer side relative to the peripheral groove 110 and protruding to an inner ring 120 side, and an inner shoulder 117 provided on the axial inner side relative to the peripheral groove 110. A seal member 140 includes a first annular portion 141 extending in the radial direction, a second annular portion 145 arranged on the radial outer side and the axial inner side relative to the first annular portion 141 and extending in the radial direction, a connecting portion 144 connecting the first annular portion 141 and the second annular portion 145, and a distal end 146 extending from an edge on the radial outer side of the second annular portion 145 toward the axial outer side. The distal end 146 is elastically deformed to the radial inner side by the outer shoulder 114, and thereby the second annular portion 145 is pressed to the inner shoulder 117.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a rolling bearing having an improved resin seal member mounted between an outer ring and an inner ring. [Background technology]

[0002] Generally, rolling bearings are fitted with seals to prevent leakage of grease filled in the raceway grooves and to prevent the intrusion of water and dust from the outside. One example of a seal is a ring-shaped resin member, with its outer periphery fitted into a circumferential groove formed in the outer ring, for example, and its inner periphery held close to the inner ring. An example of a rolling bearing fitted with such a seal is disclosed in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-135668 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0004] When a seal member is fitted into the circumferential groove of the outer ring, pressure from the circumferential groove acts on the outer periphery of the seal member, which can cause the inner periphery to warp axially outward. When the rolling bearing rotates and heats up, the seal member thermally expands, causing further warping. Warping of the inner periphery of the seal member not only increases the gap with the inner ring, impairing its function as a seal member, but also risks the seal member protruding from the end face of the rolling bearing and interfering with other components.

[0005] The present invention has been made to solve the problems associated with conventional rolling bearings as described above, and has an object to provide a rolling bearing that can prevent warping of the seal member. [Means for solving the problem]

[0006] The present invention relates to a bearing assembly comprising a first raceway ring, a second raceway ring disposed opposite the first raceway ring, a plurality of rolling elements disposed between the first raceway ring and the second raceway ring, and a sealing member made of resin attached to the first raceway ring and covering the gap between the first raceway ring and the second raceway ring, wherein the first raceway ring has raceway grooves in which the rolling elements roll, a circumferential groove provided axially outward of the raceway groove, an outer shoulder provided axially outward of the circumferential groove and protruding toward the second raceway ring, and a sealing member made of resin attached to the first raceway ring and covering the gap between the first raceway ring and the second raceway ring, and an inner shoulder provided on the sealing member, wherein the sealing member comprises a first annular portion extending radially, a second annular portion disposed radially outward and axially inward from the first annular portion and extending radially, a connecting portion connecting the first annular portion and the second annular portion, and a tip portion extending axially outward from the radially outer edge of the second annular portion, wherein the tip portion is elastically deformed radially inward by the outer shoulder, thereby pressing the second annular portion against the inner shoulder.

[0007] According to the present invention, the spring force generated by the elastic deformation of the tip portion applies a moment to the second annular portion in the direction opposite to the direction in which the sealing member warps, thereby preventing the sealing member from warping. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1A is a cross-sectional view showing a ball bearing according to a first embodiment of the present invention, and FIG. 1B is an enlarged view of a portion indicated by arrow B in FIG. [Figure 2] 1A is a cross-sectional view of the sealing member in the first embodiment, and FIG. 1B is a modified example of FIG. [Figure 3] FIG. 1(B) is a cross-sectional view showing the angle. [Figure 4] FIG. 6 is a cross-sectional view showing a sealing member according to a second embodiment of the present invention. [Figure 5] FIG. 10 is a cross-sectional view showing a sealing member according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] 1. First embodiment (1) Ball bearing structure A ball bearing according to a first embodiment of the present invention will now be described. Fig. 1 is a cross-sectional view showing a ball bearing 1 according to the first embodiment. In the following description, the direction of the center line of the ball bearing 1 will be referred to as the "axial direction," and the direction perpendicular to the axial direction will be referred to as the "radial direction." Furthermore, the direction of rotation around the axial direction will be referred to as the "circumferential direction."

[0010] 1, the ball bearing 1 is generally composed of an outer ring (first raceway) 100, an inner ring 120 (second raceway) disposed opposite the outer ring 100, a plurality of balls (rolling elements) 130 disposed between the outer ring 100 and the inner ring 120, a seal member 140 attached to the outer ring 100 to seal the gap between the outer ring 100 and the inner ring 120, and a cage 160 that holds the balls 130 at equal intervals in the circumferential direction. Each component will be described in detail below.

[0011] The outer ring 100 is annular and made of, for example, bearing steel, and has a raceway groove 101 with an arc-shaped cross section formed around the entire circumference on its inner peripheral surface. Axially outward from the raceway groove 101, a chamfered portion 102 is formed which widens outward in the axial direction.

[0012] A circumferential groove 110 is formed on the axially outer side of the chamfered portion 102, recessed radially outward. The circumferential groove 110 has a circular surface 113 with an arc-shaped cross section from an inner end 111 on the axially and radially inner side to an outer end 112 on the axially and radially outer side. An outer shoulder 114 is formed axially outward of the outer end 112, protruding radially inward. The inner circumferential surface of the outer shoulder 114 is formed with an inclined surface 115 with a linear cross section whose diameter decreases axially outward. A cylindrical surface 116 is formed axially outward of the inclined surface 115. Meanwhile, an inner shoulder 117 is formed in a portion of the circumferential groove 110 extending radially inward from the inner end 111. In this embodiment, the inner shoulder 117 is substantially parallel to the radial direction, but may be inclined relative to the radial direction. The portion from the inner shoulder 117 to the inclined surface 115 constitutes the circumferential groove 110.

[0013] 2A is a cross-sectional view showing details of the seal member 140. The seal member 140 is formed in an annular shape from a resin selected from the group consisting of aliphatic polyamides such as nylon 66 and nylon 46, semi-aromatic polyamides such as PA4T, PA6T, PA9T, and PA10T, polyimide resins such as polyamideimide and polyimide, polyarylether resins such as polyetheretherketone, aromatic polyester resins such as polybutylene terephthalate, fluorine-containing resins such as polytetrafluoroethylene, sulfur-containing novolac resins such as polyphenylene sulfide, and polyolefin resins such as polyethylene and polypropylene. The seal member 140 includes a first annular portion 141 having a uniform thickness along the radial direction. A protrusion 142 protruding axially inward is formed on the radially inner side of the first annular portion 141, and a flange portion 143 is formed on the radially inner side of the protrusion 142.

[0014] A connecting portion 144 is formed on the radially outer side of the first annular portion 141, and is inclined axially inward relative to the first annular portion 141. As shown in FIG. 1(B), the connecting portion 144 is disposed radially closer to the inner ring 120 than the inner shoulder portion 117. A second annular portion 145 is formed radially outward of the connecting portion 144, and is generally parallel to the radial direction. The second annular portion 145 is formed so that its thickness decreases from the end on the connecting portion 144 side toward the radially outer side. A tip portion 146 is formed on the radially outer end of the second annular portion 145, and extends generally parallel to the axial direction. The tip portion 146 has a constant thickness over its entire length.

[0015] 3, if the angle that inclined surface 115 makes with respect to the radial direction is α and the angle that contact surface 147 of tip portion 146 that contacts inclined surface 115 makes with respect to the radial direction in an unloaded state is β, angle α is smaller than angle β. Therefore, when seal member 140 is installed in circumferential groove 110, tip portion 146 elastically deforms by angle (β-α). This generates a spring force, pressing second annular portion 145 against inner shoulder portion 117. The difference between angle β and angle α is 1 to 60°, preferably 10 to 60°, and more preferably 20 to 50°.

[0016] Next, inner ring 120 is annular and made of, for example, bearing steel, and has raceway grooves 121 with an arc-shaped cross section formed around the entire circumference on its outer surface. A chamfered portion 122 that widens axially outward is formed axially outward from raceway groove 121. A recessed portion 123 that is recessed radially inward is formed axially outward from chamfered portion 122. A plurality of balls 130 are held at equal intervals between raceway groove 121 and raceway groove 101 of outer ring 100 by a cage 160 made of resin or metal.

[0017] (2) Effect The sealing member 140 configured as described above is fitted into the circumferential groove 110 of the outer ring 100. When fitting, when the sealing member 140 is pushed into the opening of the outer ring 100, the connecting portion 144 and the second annular portion 145 elastically deform so as to bend axially outward, passing through the outer shoulder portion 114 of the outer ring 100. Then, the area near the boundary between the second annular portion 145 and the tip portion 146 is accommodated in the circumferential groove 110, and the tip portion 146 is pressed against the inclined surface 115 of the outer shoulder 114, remaining elastically deformed, and the resulting spring force presses the second annular portion 145 against the inner shoulder portion 116.

[0018] As a result, seal member 140 lies between outer ring 100 and inner ring 120. In this state, the inner circumferential surface of flange portion 143 of seal member 140 is positioned adjacent to recessed portion 123 of inner ring 120, and first ridge 142 of seal member 140 is positioned adjacent to chamfered portion 122 of inner ring 120. A labyrinth structure is formed in this way, which prevents leakage of grease filled between outer ring 100 and inner ring 120 and prevents water and dust from entering from the outside.

[0019] (3) Effects In the ball bearing 1 having the above configuration, the spring force generated when the tip portion 146 is elastically deformed by the outer shoulder portion 114 of the outer ring 100 applies a moment to the second annular portion 145 in the direction opposite to the direction in which the sealing member 140 warps, thereby preventing the sealing member from warping.

[0020] In particular, in the first embodiment, the second annular portion 145 is formed so that its thickness decreases from the end on the connecting portion 144 side toward the radially outer side, so that the end on the connecting portion 144 side is thick and has high rigidity. This suppresses elastic deformation of the second annular portion 145 and prevents warping due to centrifugal force generated when the outer ring 100 rotates at high speed. Note that in the present invention, as shown in Fig. 2(B), the second annular portion 145a may have a constant thickness in the radial direction.

[0021] Here, if the elastic deformation of the tip portion 146 is too small, the moment applied to the second annular portion 145 is insufficient, and warping of the seal member 140 cannot be prevented. Conversely, if the elastic deformation of the tip portion 146 is too large, the spring force is too strong, and there is a risk that the tip portion 146 and the second annular portion 145 will jump out of the circumferential groove 110. In this regard, according to the first embodiment, the tip portion 146 is elastically deformed by setting the angle α that the inclined surface 115 makes with respect to the radial direction to be smaller than the angle β that the contact surface 147 of the tip portion 146 makes with respect to the radial direction in an unloaded state. Therefore, by appropriately setting the angles α and β, the elastic deformation of the tip portion 146 can be optimized.

[0022] (4) Example of change The present invention is not limited to the above-described embodiment, and various modifications can be made as follows. i) In the above embodiment, the circumferential groove 110 is formed in the outer ring 100, but it may also be formed in the inner ring 120. In that case, the connecting portion 144, the second annular portion 145, and the tip portion 146 are formed on the inner ring 120 side of the seal member 140.

[0023] ii) The present invention is not limited to the ball bearing 1 of the above embodiment, but can be applied to all rolling bearings such as roller bearings.

[0024] 2. Second embodiment FIG. 4A shows a seal member 140a according to a second embodiment of the present invention. In this seal member 140a, the angle β formed by the tip end portion 146a with respect to the radial direction is set to an obtuse angle. In this case, the angle α formed by the inclined surface 115 of the circumferential groove 110, which contacts the tip end portion 146a, with respect to the radial direction is set to be larger than the angle α shown in FIG. 3. For example, the angle α is set to an obtuse angle of 90° or greater. This second embodiment can also achieve the same effects and advantages as the first embodiment. As shown in FIG. 4B, the thickness of the second annular portion 145a of the seal member 140b can also be constant in the radial direction.

[0025] 3. Third embodiment FIG. 5A shows a seal member 140c according to a third embodiment of the present invention. In this seal member 140c, the angle β formed by the tip end portion 146b with respect to the radial direction is set to an acute angle. In this case, the angle α formed by the inclined surface 115 of the circumferential groove 110, which contacts the tip end portion 146a, with respect to the radial direction is set to be smaller than the angle α shown in FIG. 3. This third embodiment also achieves the same effects and advantages as the first embodiment. As shown in FIG. 5B, the thickness of the second annular portion 145a of the seal member 140d can also be constant in the radial direction. [Explanation of symbols]

[0026] 1...ball bearing, 100...outer ring (first raceway ring), 101...raceway groove, 102...chamfered portion, 110...circumferential groove, 111...inner end portion, 112...outer end portion, 113...circular surface portion, 114...outer shoulder portion, 115...inclined surface, 116...cylindrical surface, 117...inner shoulder portion, 120...inner ring (second raceway ring), 121...raceway groove, 122...chamfered portion, 123...recess, 130...ball (rolling element), 140, 140a, 140b, 140c, 140d...sealing member, 141...first annular portion, 142...ridge, 143...flange portion, 144...connecting portion, 145, 145a...second annular portion, 146, 146a, 146b...tip portion, 147...contact surface, 160...retainer.

Claims

1. a first bearing ring and a second bearing ring disposed opposite the first bearing ring; a plurality of rolling elements disposed between the first bearing ring and the second bearing ring; a sealing member made of resin that is attached to the first bearing ring and covers the gap between the first bearing ring and the second bearing ring; Equipped with The first bearing ring is a raceway groove in which the rolling elements roll; a circumferential groove provided axially outward of the raceway groove; an outer shoulder portion provided axially outward of the circumferential groove and protruding toward the second bearing ring; an inner shoulder portion provided axially inward of the circumferential groove; Equipped with The sealing member is a first annular portion extending radially; a second annular portion disposed radially outward and axially inward of the first annular portion and extending radially; a connecting portion that connects the first annular portion and the second annular portion; a tip portion extending axially outward from a radially outer edge portion of the second annular portion; Equipped with The tip end portion is elastically deformed radially inward by the outer shoulder portion, thereby pressing the second annular portion against the inner shoulder portion.

2. 2. The rolling bearing according to claim 1, wherein the outer shoulder portion has an inclined surface whose diameter decreases axially outward, the inclined surface causes the tip portion to elastically deform, and an angle α formed by the inclined surface with respect to the radial direction is smaller than an angle β formed by a contact surface of the tip portion that contacts the inclined surface with respect to the radial direction in an unloaded state.

3. 3. The rolling bearing according to claim 2, wherein the difference between the angle α and the angle β is 1 to 60°.

4. 4. The rolling bearing according to claim 3, wherein the difference between the angle α and the angle β is 10 to 60°.

5. 5. The rolling bearing according to claim 4, wherein the difference between the angle α and the angle β is 20 to 50°.

6. The rolling bearing according to claim 1 or 2, wherein the second annular portion has a thickness that increases from the tip end portion side toward the connecting portion side.

7. 3. The rolling bearing according to claim 1, wherein the connecting portion is disposed radially closer to the second bearing ring than the inner shoulder portion.

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