Rolling-bearing seal member

Abstract

This rolling-bearing seal member is formed from only an elastic material without a core metal, and has projections formed on an axial end face at a plurality of positions over the entire circumference or intermittently in the circumferential direction. Accordingly, even if a plurality of said rolling-bearing seal members formed from only an elastic material without a core metal are placed as stacked together, the rolling-bearing seal members are less susceptible to adhering to one another and it is easier to individually take one rolling-bearing seal member when assembling a rolling-bearing seal member to a rolling bearing.

Description

Sealing materials for rolling bearings

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

[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 include a core metal, but instead employs a seal member made solely 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. In this state, 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 makes stronger contact with the outer peripheral surface of the inner ring than when compressed air is supplied, thereby quickly stopping rotation.

[0005] Japanese Patent Application Publication No. 2017-160929

[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 include 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 the seal members 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 adhering 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.

[0008] The above object of the present invention is achieved by the following configuration: (1) An annular sealing member for a rolling bearing, formed only of an elastic material without a core metal, having convex portions formed on an axial end face thereof around the entire circumference or at multiple locations intermittently in the circumferential direction.

[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.

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

[0011] [First Embodiment] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. The embodiment of the 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, but it can also be applied to other applications such as home appliance motors. Fig. 1 is a cross-sectional view of a main part of a dental air turbine to which the rolling bearing seal member according to the first embodiment is applied, and Fig. 2 is a partially enlarged view of Fig. 1. 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 when compressed air is supplied and the air turbine is operating.

[0012] 1 to 3, a rolling bearing seal member 50 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 installed inside.

[0013] The rolling bearing 30 includes 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 Figure 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 edge of the seal member 50 is fixed in a groove 33 provided on 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 axially outer side. Note that, with respect to the seal member 50 according to this embodiment, when incorporated into a rolling bearing, the axially outer side, 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 axially outer side, and the side opposite the axially outer side (lower side in Fig. 4) is referred to as the axially inner side.

[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 that is 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 Figure 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 Figure 4 (described later) is, for example, about 0.2 mm.

[0019] Fig. 10 is a diagram showing a part of a cross section of conventional sealing members 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 with their axially outer end faces 151A facing 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 in a radial arrangement. Each of these three protrusions 55 is annular and 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 in three annular shapes with different diameters and are arranged concentrically in a radial arrangement. Although the protrusions 55 in this embodiment are formed in three concentric circles, they may be formed in a single annular shape or in 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 protrusion 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 protrusion 55 is not formed on the edge portion of the disk portion 60 that fits into the groove portion 33.

[0023] The axial height of the convex portion 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 convex portion 55 is H, and the axial thickness of the disk portion 60 excluding the convex portion 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 convex portion 55, which would otherwise be caused by the convex portion 55 being elongated thinly in the axial direction, or to prevent interference with the operation of the seal member 50 after installation in the rolling bearing 30.

[0024] 6 is a partial cross-sectional view of the seal members shown in FIG. 4 stacked vertically. As shown in FIG. 6, when two seal members 50 are stacked vertically with the convex portions 55 facing upward, 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. Here, 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 damage to the convex portions 55 during molding of the seal member 50, which deteriorates 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 lower seal member 50 and the axially inner end surface 61B of the disk portion 60 of the upper seal member 50 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 Figure 5.

[0025] Fig. 7 is a cross-sectional view perpendicular to the circumferential direction of a seal member according to a modification of this embodiment, and Fig. 8 is a partially enlarged view of the seal member of Fig. 7 as viewed from the axial outside. As shown in Figs. 7 and 8, a protrusion 57 may be formed around the entire circumference on the axially outer end surface 71A of the lip portion 70. The shape of the protrusion 57 and the height from the axially outer end surface 71A 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 A seal member 50 according to a second embodiment will now be described. FIG. 9 is a partially enlarged view of the seal member according to the second embodiment as viewed from the axially outer side, illustrating the same range as FIGS. 5 and 8 . Description of the same content as in the first embodiment will be omitted. 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" refers to the protrusions 55 being 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 in the vertical direction, the axial outer end face 51A of the sealing member 50 on the lower side in the vertical direction and the axial 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 lower seal member 50 and the axially inner end surface 61B of the disk portion 60 of the upper seal member 50 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, this specification discloses the following: (1) An annular sealing member for a rolling bearing formed only of an elastic material without a core metal, the sealing member for a rolling bearing having convex portions formed on an axial end face around the entire circumference or at multiple locations intermittently in the circumferential direction. With this configuration, overlapping sealing members are less likely to stick to each other, making it easier to remove the sealing members one by one when assembling them into a rolling bearing.

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

[0031] (3) The rolling bearing seal member according to (1) or (2), wherein the plurality of protrusions are formed so as to be aligned in the radial direction, and the plurality of protrusions are formed continuously around the entire circumference in an annular shape. With this configuration, the protrusions prevent contact between the axial end faces of the seal members around the entire circumference, making it difficult for the seal members to stick to each other. Furthermore, forming the protrusions in a circumferentially continuous shape facilitates manufacturing.

[0032] (4) The rolling bearing seal member according to any one of (1) to (3), comprising: a disk portion; and a lip portion provided on the inner diameter side of the disk portion and inclined axially outward as it approaches the inner diameter side, with the protrusion provided on the axial end face of the disk portion. With this configuration, compressed air acts intensively on the inclined lip portion, smoothing the movement of the lip portion due to the supply of compressed air and making it easier to control the rotation and stopping of the bearing. Furthermore, providing the protrusion on the disk portion prevents the disk portions of overlapping seal members from sticking to each other.

[0033] (5) The sealing member for a rolling bearing according to (4), wherein the protrusion is provided on an axially outer end surface of the disk portion. This configuration stabilizes the lowest sealing member among the stacked sealing members. Furthermore, after the sealing 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 sealing member.

[0034] (6) The rolling bearing seal member according to (4) or (5), wherein, when two of the rolling bearing seal members 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 lower rolling bearing seal member 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. With this configuration, by keeping the contact area between the stacked seal members small, the seal members are less likely to stick to each other. On the other hand, by not making the contact area extremely small, it is possible to prevent the tips of the convex portions from becoming extremely sharp, which would result in a deterioration in formability.

[0035] (7) The sealing member for a rolling bearing according to any one of (4) to (6), wherein the protrusion is provided on an axial end surface of the lip portion. With this configuration, it is possible to prevent the lip portions of the sealing members placed one on top of the other from sticking to each other.

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

[0037] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. Furthermore, the components of the above-described embodiments may be combined in any manner without departing from the spirit of the invention.

[0038] This application is based on a Japanese patent application (Patent Application No. 2024-117134) filed on July 22, 2024, the contents of which are incorporated herein by reference.

[0039] DESCRIPTION OF SYMBOLS 10 Air turbine 12 Turbine blade 14 Rotating shaft 16 Housing 18 Opening 30 Rolling bearing 32 Outer ring 33 Groove portion 34 Inner ring 35 Inclined surface 36 Ball 50 Rolling bearing seal member (seal member) 51A Axial outer end face (axial end face) 51B Axial inner end face (axial end face) 55 Convex portion 57 Convex portion 60 Disk portion 61A Axial outer end face (axial end face) 61B Axial inner end face (axial end face) 70 Lip portion 71A Axial outer end face (axial end face) 71B Axial inner end face (axial end face) H Height T Thickness S Area O Central axis

Claims

An annular sealing member for a rolling bearing formed only of an elastic material without a core metal, A sealing member for a rolling bearing, characterized in that it has protrusions formed on an axial end face thereof over the entire circumference or at a plurality of locations intermittently in the circumferential direction.

2. The sealing member for a rolling bearing according to claim 1, wherein the axial height of the protrusion is 15% or more of the axial thickness of the sealing member for a rolling bearing. 　 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. 　 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 　 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 　 5. The rolling bearing sealing member of claim 4, characterized in that when two of the rolling bearing sealing members are stacked vertically with the convex portions facing upward in the vertical direction, the sum of the contact areas between the convex portion provided on the disk portion of the lower rolling bearing sealing member in the vertical direction and the axial end face of the upper rolling bearing sealing member that does not have the convex portion is 7% or more and 20% or less of the area of ​​the axial end face of the disk portion. 　 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 　 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

Images