Seal member for rolling bearing

Abstract

To provide seal members which are hardly stuck to each other even when a plurality of seal members formed of only an elastic material without a core metal are stacked and placed, and are easily taken out one by one when the seal members are incorporated into a rolling bearing.SOLUTION: This seal member for the rolling bearing is formed of only an elastic material without a core metal, and has projecting parts formed in a plurality of places over the whole periphery or intermittently in the peripheral direction on an axial directional end surface.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a sealing member for a rolling bearing. [Background technology]

[0002] Rolling bearings are widely used to support the rotating parts of various rotary machines. Among these rolling bearings, those incorporating a seal member between the outer and inner rings are known.

[0003] Rolling bearings are also used in the dental air turbine described in Patent Document 1. In the dental air turbine described in Patent Document 1, compressed air is directed against the turbine blades to rotate the rotating shaft at high speed, and rotation stops when the supply of compressed air is cut off. Furthermore, when the dental air turbine is operating, the compressed air passes through the inside of the rolling bearing and is released outside the dental air turbine.

[0004] The rolling bearing of the dental air turbine described in Patent Document 1 does not have a core metal, and uses a seal member made only of an elastic material. The outer diameter side of the seal member is fixed to the outer ring of the bearing. The inner diameter side of the seal member is provided with a lip portion, which contacts the outer peripheral surface of the inner ring when compressed air is not supplied. When compressed air is supplied, the lip portion elastically deforms axially outward (downstream in the air flow) due to the compressed air. At this time, the contact area between the lip portion and the outer peripheral surface of the inner ring is smaller than when compressed air is not supplied, allowing the rotating shaft to rotate at high speed. Furthermore, when the supply of compressed air is stopped, the seal member returns to its original shape, and the lip portion contacts the outer peripheral surface of the inner ring more strongly than when compressed air is supplied, thereby quickly stopping rotation. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-160929 Summary of the Invention [Problem to be solved by the invention]

[0006] The seal member used in the dental air turbine described in Patent Document 1 is a seal member that is designed to undergo elastic deformation due to compressed air, and therefore does not have a core metal and is made solely of an elastic material. When multiple seal members are stacked before being assembled into a bearing, for example, the weight of the seal members causes them to elastically deform, causing the seal members to adhere to each other and become prone to sticking. This makes it difficult to pick up and transport the seal members one by one using vacuum suction or tweezers during bearing assembly, slowing down bearing production. While seal members that are generally coated to prevent them from sticking to each other are known, when the seal members are made solely of an elastic material and are prone to sticking to each other, the anti-stick coating alone may not be effective enough.

[0007] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide sealing members that are less likely to stick to each other even when multiple sealing members are stacked before being incorporated into a rolling bearing, and that can be easily removed one by one. [Means for solving the problem]

[0008] The above object of the present invention can be achieved by the following configuration. (1) An annular sealing member for a rolling bearing formed only of an elastic material without a core metal, The axial end surface has protrusions formed over the entire circumference or at multiple locations intermittently in the circumferential direction. Sealing material for rolling bearings. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide seal members that are unlikely to stick to each other even when stacked and that can be easily removed one by one when assembling the seal members into a rolling bearing. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view of a main part of a dental air turbine to which a sealing member for a rolling bearing according to a first embodiment is applied. [Figure 2] FIG. 2 is a partially enlarged view of FIG. [Figure 3] FIG. 3 is a partially enlarged view of the same area as FIG. 2 in a state where compressed air is being supplied. [Figure 4] FIG. 4 is a cross-sectional view perpendicular to the circumferential direction of the seal member according to the first embodiment. [Figure 5] FIG. 5 is a partially enlarged view of the seal member of FIG. 4 as viewed from the outside in the axial direction. [Figure 6] FIG. 6 is a diagram showing a part of a cross section of the sealing members of FIG. 4 in a state where they are stacked in the vertical direction. [Figure 7] FIG. 7 is a cross-sectional view perpendicular to the circumferential direction of a seal member according to a modified example of the first embodiment. [Figure 8] FIG. 8 is a partially enlarged view of the seal member of FIG. 7 as viewed from the outside in the axial direction. [Figure 9] FIG. 9 is a partially enlarged view of the seal member according to the second embodiment as viewed from the outside in the axial direction. [Figure 10] FIG. 10 is a diagram showing a part of a cross section of conventional sealing members in a state where they are stacked in the vertical direction. DETAILED DESCRIPTION OF THE INVENTION

[0011] [First embodiment] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. While an embodiment of a rolling bearing seal member according to the present invention will be described using an example in which it is applied to a rolling bearing used in a dental air turbine, it can also be applied to other applications such as home appliance motors. FIG. 1 is a cross-sectional view of a main portion of a dental air turbine to which a rolling bearing seal member according to a first embodiment is applied, and FIG. 2 is a partially enlarged view of FIG. 1. Note that FIGS. 1 and 2 show a state in which compressed air is not supplied and the air turbine is stopped. FIG. 3 is a partially enlarged view of the same area as FIG. 2 in a state in which compressed air is supplied and the air turbine is operating.

[0012] 1 to 3, a sealing member 50 for a rolling bearing according to the present invention is applied to a rolling bearing 30 used in an air turbine 10. The air turbine 10 comprises turbine blades 12 that rotate when subjected to compressed air, a rotating shaft 14 that is fixed integrally with the turbine blades 12 and has one axial end (the left end in FIG. 1) to which a tool such as a dental treatment tool can be attached, and a rolling bearing 30 that rotatably holds the rotating shaft 14 relative to a housing 16. The housing 16 can be separated in the left-right direction in FIG. 1, and the turbine blades 12, rotating shaft 14, and rolling bearing 30 can be assembled inside.

[0013] The rolling bearing 30 comprises an outer ring 32, an inner ring 34, a plurality of balls 36 that roll between the outer ring 32 and the inner ring 34, and a rolling bearing seal member 50 that is fixed to the axial end of the outer ring 32. Hereinafter, the rolling bearing seal member 50 will be simply referred to as the seal member 50.

[0014] The housing 16 has an opening 18 that communicates from the outside of the housing 16 to a space that houses the turbine blades 12. Compressed air is supplied to the interior of the air turbine 10 through the opening 18, and the pressure of the compressed air rotates the turbine blades 12. Furthermore, as shown in Fig. 3 , the compressed air supplied to the interior of the air turbine 10 rotates the turbine blades 12, and then passes between the outer ring 32 and inner ring 34 of the rolling bearing 30 and flows in the direction of arrow III.

[0015] As shown in FIGS. 1 to 3 , the seal member 50 is formed in an annular shape, and the outer diameter side edge of the seal member 50 is fixed in a groove 33 provided in the inner peripheral surface of the outer ring 32. Furthermore, when compressed air is not supplied, the seal member 50 contacts an inclined surface 35 formed on the outer peripheral surface of the axial end of the inner ring 34. When compressed air is supplied, the seal member 50 is pushed toward the downstream side of the compressed air. At this time, the seal member 50 separates from the inclined surface 35, or the contact area between the seal member 50 and the inclined surface 35 decreases. This reduces the contact resistance that limits the rotation of the rolling bearing 30, allowing the rolling bearing 30 and turbine blades 12 to rotate at high speeds. Furthermore, when the supply of compressed air is stopped, the seal member 50 returns to its original shape and makes stronger contact with the inclined surface 35 than when compressed air was supplied, thereby quickly stopping the rotation of the rolling bearing 30 and turbine blades 12.

[0016] The detailed configuration of the seal member 50 will be described below. Fig. 4 is a cross-sectional view perpendicular to the circumferential direction of the seal member according to this embodiment, and Fig. 5 is a partially enlarged view of the seal member of Fig. 4 as viewed from the axial outside. Note that when the seal member 50 according to this embodiment is incorporated into a rolling bearing, the axial outside, i.e., the direction facing away from the space between the inner ring and the outer ring (upper side in Fig. 4), is referred to as the axial outside, and the side opposite the axial outside (lower side in Fig. 4) is referred to as the axial inside.

[0017] As shown in FIGS. 2 to 5 , the seal member 50 is formed in an annular shape centered on the central axis O and has an axially outer end surface 51A and an axially inner end surface 51B facing the axial direction. The seal member 50 also has a disk portion 60 and a lip portion 70 provided around the entire inner diameter side of the disk portion 60 and inclined axially outward as it approaches the inner diameter side. The axially outer end surface 51A of the seal member 50 includes the axially outer end surface 61A of the disk portion 60 and the axially outer end surface 71A of the lip portion 70. The axially inner end surface 51B includes the axially inner end surface 61B of the disk portion 60 and the axially inner end surface 71B of the lip portion 70. The inclination angle θ of the lip portion 70 is preferably set to be between 20° and 60°, and more preferably between 25° and 50°. This allows the compressed air to act efficiently on the lip portion 70, making the movement of the lip portion 70 smoother and making it easier to control the rotation and stopping of the rolling bearing 30.

[0018] As shown in Fig. 4, the seal member 50 according to this embodiment does not include a core metal and is formed solely from an elastic material so that it can be elastically deformed by compressed air. Specifically, it is preferably formed from any of the following rubber materials: acrylic rubber, nitrile rubber, fluororubber, silicone rubber, ethylene propylene rubber, chloroprene rubber, and natural rubber. The axial thickness of the seal member 50 is also thinner than that of typical seal members. In this embodiment, the thickness T shown in Fig. 4 (described later) is, for example, about 0.2 mm.

[0019] Fig. 10 is a diagram showing a part of a cross section in a state where conventional sealing members are stacked in the vertical direction. Note that the vertical direction refers to the vertical direction (the direction of gravity) or a substantially vertical direction, the upper side in the vertical direction refers to the upper side in the vertical direction or a substantially vertical direction (the upper side in Fig. 10), and the lower side in the vertical direction refers to the side opposite the upper side in the vertical direction (the lower side in Fig. 10). The same applies to the vertical direction in Fig. 6 described below.

[0020] When a seal member is assembled into a bearing, it may be transported while being suctioned by a vacuum suction device. For example, the seal member 100 shown in FIG. 10 is transported while its axially outer end face 151A is suctioned by a vacuum suction device. Therefore, prior to assembly, multiple seal members 100 are stacked and placed so that their axially outer end faces 151A face upward. In this case, the axially outer end face 151A of the lower seal member 100 (the axially outer end face 161A of the disk portion 160 and the axially outer end face 171A of the lip portion 170) and the axially inner end face 151B of the upper seal member 100 (the axially outer end face 161B of the disk portion 160 and the axially outer end face 171B of the lip portion 170) come into contact with each other and become stuck together. Furthermore, if the seal members 100 are formed solely from an elastic material without a core, the seal members 100 are particularly likely to adhere to each other.

[0021] To prevent the above-described adhesion of the seal members to each other, the seal member 50 has protrusions 55 formed around the entire circumference or at multiple locations intermittently in the circumferential direction on its axial end surface. In this embodiment, as shown in FIGS. 2 to 5 , the seal member 50 has protrusions 55 formed around the entire circumference on the axially outer end surface 51A of the seal member 50 and protruding in the axial direction. Here, "formed around the entire circumference" refers to the protrusions 55 being continuously formed around the entire circumference in an annular shape. In this embodiment, the protrusions 55 include three protrusions 55 formed so as to be aligned in the radial direction. These three protrusions 55 are each annular and are continuously formed around the entire circumference on the axially outer end surface 61A of the disk portion 60. That is, the three protrusions 55 are formed as three annular rings with different diameters and are arranged concentrically in the radial direction. Note that, although the protrusions 55 in this embodiment are formed as three concentric circles, they may be formed as one annular ring or as four or more concentric circles. As described above, by providing the protrusions 55 around the entire circumference of the seal member 50, even when the seal members 50 are stacked in the vertical direction, the axially outer end surface 51A of the vertically lower seal member 50 and the axially inner end surface 51B of the vertically upper seal member 50 are less likely to come into contact with each other regardless of their circumferential positions, thereby preventing the seal members 50 from sticking to each other.

[0022] Furthermore, the cross-sectional shape of the protrusions 55 according to this embodiment, taken perpendicular to the circumferential direction, has an arc-shaped tip. Furthermore, the seal member 50 according to this embodiment has a structure in which the edge portion on the outer diameter side is fitted into the groove portion 33 of the outer ring 32. Therefore, the protrusions 55 are not formed on the edge portion of the disk portion 60 that fits into the groove portion 33.

[0023] The axial height of the protrusion 55 is 15% or more of the axial thickness of the seal member 50. That is, as shown in FIG. 4 , if the height from the axially outer end surface 61A of the disk portion 60 to the tip of the protrusion 55 is H, and the axial thickness of the disk portion 60 excluding the protrusion 55 is T, the height H is preferably 15% or more of the thickness T. When the seal members 50 are stacked vertically, setting the height H as described above prevents the axially outer end surface 51A of the lower seal member 50 from contacting the axially inner end surface 51B of the upper seal member 50. This prevents the seal members 50 from sticking together. On the other hand, the height H is preferably 50% or less of the thickness T. This is to prevent deterioration of formability and damage to the protrusion 55, which would otherwise be caused by the protrusion 55 being elongated thinly in the axial direction, or to prevent interference with the operation of the seal member 50 after it is incorporated into the rolling bearing 30.

[0024] Fig. 6 is a partial cross-sectional view of the seal members of Fig. 4 stacked vertically. When two seal members 50 are stacked vertically with their convex portions 55 facing upward, as shown in Fig. 6, the tip of the convex portion 55 of the lower seal member 50 and the axially inner end surface 61B of the disk portion 60 of the upper seal member 50 form a contact surface. The smaller the contact area between the stacked seal members 50, the less likely they are to adhere to each other. On the other hand, reducing the contact area, i.e., making the tip of the convex portion 55 more pointed, leads to chipping of the convex portion 55 during molding of the seal member 50, resulting in poor moldability. Due to the conflicting circumstances described above, it is preferable that the total contact area between the convex portion 55 provided on the disk portion 60 of the seal member 50 on the lower side in the vertical direction and the axially inner end surface 61B of the disk portion 60 of the seal member 50 on the upper side in the vertical direction be 7% to 20% of the area of ​​the axially outer end surface 61A of the disk portion 60. The area of ​​the axially outer end surface 61A of the disk portion 60 is the projected area of ​​the disk portion 60 when the seal member 50 is viewed from the outside in the axial direction, and is the area within the range indicated by the dashed line S in FIG. 5 .

[0025] Fig. 7 is a cross-sectional view perpendicular to the circumferential direction of a sealing member according to a modified example of this embodiment, and Fig. 8 is a partially enlarged view of the sealing member of Fig. 7 as viewed from the outside in the axial direction. As shown in Figs. 7 and 8, a protrusion 57 may be formed around the entire circumference on the outside end surface 71A in the axial direction of the lip portion 70. The shape of the protrusion 57 and the height from the outside end surface 71A in the axial direction to the tip of the protrusion 57 are formed to be the same as the shape and height H of the protrusion 55.

[0026] In this embodiment, the protrusion 55 is preferably formed on the axially outer end surface 61A of the disk portion 60, but may be formed on either the axially outer end surface 61A or the axially inner end surface 61B of the disk portion 60, or may be formed on both surfaces. Furthermore, the protrusion 57 is preferably formed on the axially outer end surface 71A of the lip portion 70, but may be formed on either the axially outer end surface 71A or the axially inner end surface 71B of the lip portion 70, or may be formed on both surfaces. Furthermore, in this embodiment, the cross-sectional shapes of the protrusions 55 and 57 are arc-shaped, but they may be trapezoidal or other shapes, and are not limited to arc-shaped. Furthermore, although the seal member 50 has an inclined lip portion 70, the seal member may be formed only with the disk portion 60 without the lip portion 70.

[0027] [Second embodiment] The seal member 50 according to the second embodiment will be described below. FIG. 9 is a partially enlarged view of the seal member according to the second embodiment as viewed from the axially outer side, and illustrates the same range as FIGS. 5 and 8. The same content as in the first embodiment will not be described. As shown in FIG. 9, the seal member 50 according to this embodiment has protrusions 55 formed at multiple locations intermittently in the circumferential direction. Here, "formed intermittently in the circumferential direction" means that the protrusions 55 are formed intermittently so as to be dispersed in the circumferential direction. In this embodiment, the protrusions 55 are provided on the axially outer end surface 61A of the disk portion 60, and multiple protrusions 55 are formed so as to be dispersed in the circumferential and radial directions. In other words, the protrusions 55 do not need to be aligned in the circumferential and radial directions, as long as they are formed at a predetermined interval at least in the circumferential direction. As a result, even when the sealing members 50 are stacked vertically, the axially outer end face 51A of the sealing member 50 on the lower side in the vertical direction and the axially inner end face 51B of the sealing member 50 on the upper side in the vertical direction are less likely to come into contact with each other regardless of their circumferential positions, thereby preventing the sealing members 50 from sticking together.

[0028] In this case, the shape of the protrusions 55 is arbitrary, but the total contact area between the protrusions 55 provided on the disk portion 60 of the seal member 50 on the vertically lower side and the axially inner end surface 61B of the disk portion 60 of the seal member 50 on the vertically upper side is preferably 7% to 20% of the area of ​​the axially outer end surface 61A of the disk portion 60. In addition, the axial height of the protrusions 55 is preferably 15% to 50% of the axial thickness of the seal member 50.

[0029] As described above, the present specification discloses the following: (1) An annular sealing member for a rolling bearing formed only of an elastic material without a core metal, The axial end surface has protrusions formed over the entire circumference or at multiple locations intermittently in the circumferential direction. Sealing material for rolling bearings. According to this configuration, the overlapping seal members are less likely to stick to each other, and the seal members can be easily removed one by one when being assembled into the rolling bearing.

[0030] (2) The axial height of the protrusion is 15% or more of the axial thickness of the sealing member for a rolling bearing. A sealing member for a rolling bearing according to (1). According to this configuration, it is possible to prevent the axial end faces of the seal members from coming into contact with each other, thereby improving the sticking prevention effect.

[0031] (3) The protrusions are formed in a plurality of rows aligned in the radial direction, The plurality of protrusions are formed continuously around the entire circumference in an annular shape. A sealing member for a rolling bearing according to (1) or (2). According to this configuration, the convex portion prevents contact between the axial end faces of the seal members over the entire circumference, making it difficult for the seal members to stick to each other. In addition, the convex portion has a shape that is continuous in the circumferential direction, making it easier to manufacture.

[0032] (4) The sealing member for a rolling bearing is A disk part and a lip portion provided on an inner diameter side of the disk portion and inclined axially outward as it approaches the inner diameter side; and The disk portion has the convex portion on the axial end surface. A sealing member for a rolling bearing according to any one of (1) to (3). With this configuration, the compressed air acts intensively on the inclined lip portion, making the movement of the lip portion due to the supply of compressed air smoother and making it easier to control the rotation and stopping of the bearing. Also, by providing a protrusion on the disk portion, it is possible to prevent the disk portions of overlapping sealing members from sticking to each other.

[0033] (5) The convex portion is provided on an axially outer end surface of the disk portion. (4) A sealing member for a rolling bearing according to (4). This configuration stabilizes the seal member located at the bottom of the stack of seal members. Furthermore, after the seal member is installed in the bearing, the protrusion is less likely to come into contact with the flow of compressed air, stabilizing the operation of the seal member.

[0034] (6) When the two sealing members for rolling bearings are stacked vertically with the convex portions facing upward in the vertical direction, the sum of the contact areas between the convex portions provided on the disk portion of the sealing member for rolling bearing that is lower in the vertical direction and the axial end face that is not provided with the convex portion of the sealing member for rolling bearing that is upper in the vertical direction is 7% or more and 20% or less of the area of ​​the axial end face of the disk portion. A sealing member for a rolling bearing according to (4) or (5). This configuration reduces the contact area between the overlapping seal members, making them less likely to stick to each other. On the other hand, by not making the contact area too small, it is possible to prevent the tips of the protrusions from becoming too sharp, which would otherwise deteriorate moldability.

[0035] (7) The convex portion is provided on an axial end surface of the lip portion. A sealing member for a rolling bearing according to any one of (4) to (6). This configuration can prevent the lip portions of the overlapping seal members from sticking to each other.

[0036] (8) The convex portion is provided on an axially outer end surface of the lip portion. A sealing member for a rolling bearing according to any one of (4) to (7). According to this configuration, after the seal member is assembled into the bearing, the protrusion is less likely to come into contact with the flow of compressed air, and the operation of the seal member is stable. [Explanation of symbols]

[0037] 10 Air Turbine 12 turbine blades 14 Rotation axis 16 Housing 18 Opening 30 Rolling bearings 32 outer ring 33 Groove 34 Inner Circle 35 Slope 36 balls 50 Sealing material for rolling bearings (sealing material) 51A Axial outer end face (axial end face) 51B Axial inner end face (Axial end face) 55 Convex part 57 Convex part 60 Disc Section 61A Axial outer end face (Axial end face) 61B Axial inner end face (Axial end face) 70 Lip 71A Axial outer end face (axial end face) 71B Axial inner end face (Axial end face) H Height T Thickness S area O center axis

Claims

1. An annular sealing member for a rolling bearing formed only of an elastic material without a core metal, The axial end face has protrusions formed all around the circumference or at multiple locations intermittently in the circumferential direction. A sealing member for a rolling bearing, characterized in that

2. The axial height of the protrusion is 15% or more of the axial thickness of the sealing member for a rolling bearing.

2. The sealing member for a rolling bearing according to claim 1, wherein the sealing member is a tubular member.

3. The protrusions are formed in a plurality so as to be aligned in the radial direction, The plurality of protrusions are formed continuously around the entire circumference in an annular shape.

2. The sealing member for a rolling bearing according to claim 1, wherein the sealing member is a tubular member.

4. The sealing member for a rolling bearing comprises: A disk part and a lip portion provided on an inner diameter side of the disk portion and inclined axially outward as it approaches the inner diameter side; and The protrusion is provided on an axial end surface of the disk portion. The sealing member for a rolling bearing according to any one of claims 1 to 3, characterized in that

5. The protrusion is provided on an axially outer end surface of the disk portion. The sealing member for a rolling bearing according to claim 4, characterized in that

6. When the two rolling bearing seal members are stacked in the vertical direction with the convex portions facing upward in the vertical direction, the total contact area between the convex portion provided on the disk portion of the lower rolling bearing seal member in the vertical direction and the axial end face of the upper rolling bearing seal member that does not have the convex portion is 7% to 20% of the area of ​​the axial end face of the disk portion. The sealing member for a rolling bearing according to claim 4, characterized in that

7. The protrusion is provided on an axial end surface of the lip portion. The sealing member for a rolling bearing according to claim 4, characterized in that

8. The protrusion is provided on an axially outer end surface of the lip portion. The sealing member for a rolling bearing according to claim 4, characterized in that

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