Sealing member for rolling bearing and rolling bearing

Abstract

To provide an inexpensive sealing member for a rolling bearing and a rolling bearing that can suppress pressure changes inside the rolling bearing and prevent grease leakage from inside the rolling bearing and the intrusion of foreign matter from outside the rolling bearing. [Solution] The sealing member for a rolling bearing has an annular core and an elastic sealing material fixed to the core, the core includes an annular portion and has at least one hole that penetrates the annular portion from one axial side to the other axial side. The elastic sealing material has a closing portion provided to close the hole, and the closing portion has at least one axially projecting peak and / or valley.

Description

Technical Field

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

Background Art

[0002] For example, rolling bearings are widely used to support the rotating parts of mechanical products such as automobile wheels and rolling mills in steel facilities. In rolling bearings, in order to prevent friction and wear during rotation, those filled with lubricating grease (hereinafter sometimes simply referred to as grease) are known. In such rolling bearings, it is well known to seal the space between the inner ring and the outer ring with a sealing member so that the grease does not leak out. Also, a sealing member is used for the purpose of preventing foreign matter from entering the rolling bearing from the outside.

[0003] In a rolling bearing provided with a sealing member, for example, the temperature inside the bearing rises due to frictional heat generated by rotation or the like, and the air inside the bearing expands. As a result, the pressure inside the sealed bearing increases, the contact surface pressure between the seal lip and the inner ring or the outer ring fluctuates, which may cause an increase in torque, or the seal lip may be pushed out between the inner ring and the outer ring, and the grease may leak out to the outside of the bearing. Therefore, in the sealing member described in Patent Document 1, in order to prevent the grease from leaking due to the pressure difference between the inside and outside of the bearing, a structure is adopted in which a breathable porous filter is adhered to a hole penetrating in the axial direction provided in the sealing member. In this sealing member, while preventing the leakage of the grease inside the bearing by the breathable porous filter, it allows the entry and exit of gas and attempts to adjust the internal pressure of the bearing.

[0004] Also, in the sealing member described in Patent Document 2, a structure is adopted in which a thin elastic member is provided in a hole penetrating in the axial direction provided in the sealing member so as to close the hole. Thereby, the thin elastic member expands and contracts in accordance with the volume change of the air inside the bearing, and attempts to adjust the internal pressure of the bearing.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-146299 [Patent Document 2] Japanese Patent Publication No. 2011-226511 [Overview of the project] [Problems that the invention aims to solve]

[0006] On the other hand, the sealing member described in Patent Document 1 has a structure in which a porous filter is bonded to holes provided in the sealing member, which increases the manufacturing cost compared to a sealing member without a filter. Furthermore, with the porous filter of the sealing member described in Patent Document 1, it cannot be ruled out that contents sealed inside the rolling bearing, such as grease, or foreign matter from outside the rolling bearing, may pass through the porous filter. In addition, with the sealing member described in Patent Document 2, it is conceivable that the pressure changes inside the bearing may not be fully absorbed by the expansion and contraction of the thin-walled elastic member alone, and the pressure inside the bearing may not be kept constant.

[0007] The present invention has been made in view of the above problems, and its purpose is to provide a sealing member for a rolling bearing and a rolling bearing at low cost that can suppress pressure changes inside the rolling bearing and prevent grease leakage from inside the rolling bearing and the intrusion of foreign matter from outside the rolling bearing. [Means for solving the problem]

[0008] The above objective of the present invention is achieved by the following configuration. (1) Having an annular core and an elastic sealing material fixed to the core, The core metal includes an annular portion and has at least one hole that penetrates the annular portion in the axial direction. The elastic sealing material has a closing portion provided to close the hole, The closing portion has at least one peak and / or valley that protrudes in the axial direction. A sealing member for rolling bearings, characterized by the above. (2) Outer ring and, Insider, A plurality of rolling elements are arranged to roll freely between the outer ring and the inner ring, A sealing member for a rolling bearing, which is fixed to one of the outer ring and the inner ring and slides against the other, thereby sealing the internal space between the outer ring and the inner ring, A rolling bearing equipped with, The aforementioned sealing member for rolling bearings is the sealing member for rolling bearings described in (1). A rolling bearing characterized by the following. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a sealing member for a rolling bearing that can suppress pressure changes inside the bearing and prevent grease leakage from inside the bearing and intrusion of foreign matter from outside the bearing, and a rolling bearing equipped with the sealing member for a rolling bearing. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a cross-sectional view of the main part of a rolling bearing according to an embodiment of the present invention. [Figure 2] Figure 2 is a perspective view of the inner surface of a sealing member for a rolling bearing according to an embodiment of the present invention. [Figure 3] Figure 3 is a cross-sectional view taken along the line III-III in Figure 2. [Figure 4] Figure 4 is a cross-sectional view taken along the line IV-IV in Figure 2. [Figure 5] Figure 5 is a cross-sectional view taken along the VV line in Figure 2. [Figure 6] Figure 6 is a cross-sectional view taken along the line VI-VI in Figure 2. [Figure 7] Figure 7 is a magnified view of a portion of Figure 2. [Figure 8] Figure 8 is a partially enlarged view showing the same area as in Figure 7 of a sealing member for a rolling bearing according to a modified embodiment of the present invention. [Modes for carrying out the invention]

[0011] Hereinafter, embodiments according to the present invention will be described based on the accompanying drawings. FIG. 1 is a cross-sectional view of a main part of a rolling bearing according to an embodiment of the present invention. Note that FIG. 1 shows from the axial center part to one axial end part of the rolling bearing. In the following description, in the axial direction, the direction toward the outside of the rolling bearing (the left side in FIG. 1) is called the axial outer side, and the side opposite to the axial outer side, which is the direction toward the inside of the rolling bearing (the right side in FIG. 1), is called the axial inner side. Also, in the radial direction, the direction away from the axis (the upper side in FIG. 1) is called the radial outer side, and the side opposite to the radial outer side (the lower side in FIG. 1) is called the radial inner side. Note that the rolling bearing according to the present embodiment has a shape that is substantially symmetric with respect to the axial center part. Therefore, although only one axial half part from the axial center part of the rolling bearing is shown and described in FIG. 1, the other axial half part not shown has the same structure.

[0012] As shown in FIG. 1, the rolling bearing 10 according to the present embodiment includes an outer ring 20 having an outer ring raceway surface 21 on its inner peripheral surface, an inner ring 30 having an inner ring raceway surface 31 on its outer peripheral surface, a plurality of rolling elements 40 disposed between the outer ring 20 and the inner ring 30, a cage 45 that holds the rolling elements 40 so as to be rotatable, and a sealing member 50 for a rolling bearing that is fixed to the inner peripheral surface of the outer ring 20 and is in sliding contact with the outer peripheral surface of the inner ring 30 to seal the internal space 100 between the outer ring 20 and the inner ring 30. Hereinafter, the sealing member 50 for a rolling bearing will be simply referred to as the sealing member 50.

[0013] The outer ring 20 has an outer ring raceway surface 21 whose cross-section perpendicular to the circumferential direction is arc-shaped at the axial center part of the inner peripheral surface. Also, the outer ring 20 has a seal locking groove 22 that fits with the sealing member 50 and fixes the sealing member 50 at the axial end part of the inner peripheral surface. Further, the outer ring 20 has a side wall surface 23 that extends radially inward from the axial inner end of the seal locking groove 22 and faces the axial outer side.

[0014] The inner ring 30 has an inner ring raceway surface 31 on the axially central portion of the outer peripheral surface, the cross section perpendicular to the circumferential direction of which is arc-shaped. Further, the inner ring 30 has a sliding contact surface 32 that slidably contacts the seal member 50 at the axially end portion of the outer peripheral surface. Furthermore, the inner ring 30 has a side wall surface 33 that extends radially outward from the axially inner end portion of the sliding contact surface 32 and faces axially outward.

[0015] The rolling elements 40 are balls and are arranged to be freely rotatable between the outer ring raceway surface 21 and the inner ring raceway surface 31. Further, the rolling elements 40 are held at equal intervals in the circumferential direction by a crowned retainer 45.

[0016] Hereinafter, the seal member 50 will be described. FIG. 2 is a perspective view of the inner surface of the rolling bearing seal member according to the embodiment of the present invention. FIG. 3 is a cross-sectional view taken along the arrow III-III in FIG. 2. FIG. 4 is a cross-sectional view taken along the arrow IV-IV in FIG. 2. FIG. 5 is a cross-sectional view taken along the arrow V-V in FIG. 2. FIG. 6 is a cross-sectional view taken along the arrow VI-VI in FIG. 2. FIG. 7 is a partially enlarged view of FIG. 2. Note that FIG. 2 shows the inner surface of the seal member 50 facing the internal space 100 of the bearing, that is, the surface facing axially inward in FIG. 1.

[0017] As shown in FIGS. 1 to 4, the seal member 50 has an annular core metal 51 and an elastic seal material 60 fixed to the core metal 51. The core metal 51 is manufactured by subjecting a metal plate such as a cold-rolled steel sheet to press working. The elastic seal material 60 is made of rubber such as acrylonitrile-butadiene rubber (NBR), acrylic rubber (ACM), or fluororubber (FKM).

[0018] As shown in Figures 2 to 4, the mandrel 51 has a radially extending annular portion 52, a sloping portion 53 formed at the radially inner end of the annular portion 52, and a rim portion 54 formed at the radially outer end of the annular portion 52, as shown in Figures 3 and 4 in particular. The sloping portion 53 extends from the radially inner end of the annular portion 52 so as it moves radially inward, it moves axially inward. The rim portion 54 is formed to protrude axially inward from the radially outer end of the annular portion 52. The annular portion 52 also has at least one hole that penetrates from the axially outer to the axially inner. In this embodiment, as shown in Figures 2 and 4 in particular, the annular portion 52 has a plurality of elongated holes 55 that extend along the circumferential direction. More specifically, the annular portion 52 has four elongated holes 55 formed at equal intervals in the circumferential direction, with a circumferential length longer than the radial width.

[0019] As shown in Figures 2 to 4, the elastic sealing material 60 includes a base portion 61 that covers the axially outer surface of the core metal 51, an outer peripheral edge portion 62 that covers the outer peripheral surface of the rim portion 54 of the core metal 51 and is formed to bulge radially outward, a seal lip 63 that extends radially inward from the core metal 51, and a grease lip 64 that covers the inner peripheral surface and the axially inward surface of the inclined portion 53 of the core metal 51 and protrudes axially inward from the seal lip 63. The base portion 61 is fixed to the axially outer surface of the core metal 51, the outer peripheral edge portion 62 is connected to the radially outer end of the base portion 61, and the seal lip 63 is connected to the radially inward end of the base portion 61.

[0020] The outer peripheral edge 62 is locked in place when its axially inner surface abuts against the side wall surface 23 of the outer ring 20, and the projection 62a formed at the radially outer end of the outer peripheral edge 62 is pressed into the seal locking groove 22 of the outer ring 20. This fixes the seal member 50 to the outer ring 20.

[0021] The seal lip 63 elastically slides against the sliding contact surface 32 provided at the axial end of the inner ring 30, and seals the internal space 100 while rotating relative to the inner ring 30.

[0022] The grease slip 64 is positioned opposite and close to the radially outer end of the side wall surface 33 located axially inward of the sliding contact surface 32. The grease slip 64 prevents the sealed grease from reaching the sliding contact surface 32, but it is desirable that it is positioned with a slight gap between it and the side wall surface 33 of the inner ring 30, without contact, in order to reduce frictional resistance.

[0023] As shown in Figures 2, 4, and 7, the elastic sealing material 60 has a closing portion 65 provided to close the elongated hole 55 of the annular portion 52 in the core metal 51. The closing portion 65 is formed in substantially the same shape as the elongated hole 55, and the outer edge of the closing portion 65 is connected to the base portion 61 around its entire circumference. In other words, the closing portion 65 is formed integrally with the elastic sealing material 60.

[0024] Furthermore, the closing section 65 has a bellows structure in which peaks 66 and valleys 67 are alternately continuous. In this embodiment, the peaks 66 and valleys 67 are alternately continuous in the radial direction. The peaks 66 protrude axially outward from the base 61, and the valleys 67 protrude axially inward from the base 61. The peaks 66 and valleys 67 are formed such that the ridges of the tips of the peaks 66 and valleys 67 extend in the longitudinal direction, i.e., the circumferential direction, of the elongated hole 55. In addition, radially adjacent peaks 66 and valleys 67 are connected by connecting sections 68. The closing section 65 may have only one of the peaks 66 that protrude axially outward and the valleys 67 that protrude axially inward, and it is sufficient to have at least one peak 66 or valley 67.

[0025] The projected area of ​​the closure portion 65, as viewed from the axial direction, is formed to be larger than the projected area of ​​the elongated hole 55, as viewed from the axial direction. The closure portion 65 is formed in region S1 shown in Figure 4, and the radially inner end of the closure portion 65 and the base portion 61 are connected at a position radially inward from the inner surface 55a that defines the radially inner end of the elongated hole 55. Furthermore, a portion of the radially outer end of the closure portion 65 is fixed to the inner surface 55b that defines the radially outer end of the elongated hole 55, and a portion is connected to the base portion 61. In other words, the region S1 in which the closure portion 65 is formed extends radially inward from the region S2 in which the elongated hole 55 is formed, and the area of ​​region S1 as viewed from the axial direction is larger than the area of ​​region S2. This makes the closure portion 65 more flexible in expanding and contracting, and more flexible in absorbing pressure changes. Note that the projected area of ​​the closure portion 65 as viewed from the axial direction may be equal to or less than the projected area of ​​the elongated hole 55 as viewed from the axial direction.

[0026] As shown in Figures 2, 4 to 7, the peaks 66 and valleys 67 are formed such that the axial width between the tip of the peak 66 and the tip of the valley 67 on the circumferential central side of the closed portion 65 is wider than the axial width between the tip of the peak 66 and the tip of the valley 67 on the circumferential end side of the closed portion 65. Here, in Figure 2, the circumferential position forming the section viewed from arrow IV-IV is called position A, the circumferential position forming the section viewed from arrow VV is called position B, and the circumferential position forming the section viewed from arrow VI-VI is called position C. Position A is the circumferential central part of the closed portion 65.

[0027] As shown in Figure 4, Wa is the axial width between the tip of the peak 66 and the tip of the valley 67 at position A in Figure 2. Also, as shown in Figure 5, Wb is the axial width between the tip of the peak 66 and the tip of the valley 67 at position B in Figure 2. In this case, width Wa is greater than width Wb. In this embodiment, near position B, the axial width between the tip of the peak 66 and the tip of the valley 67 increases from the circumferential end side of the closing portion 65 toward the circumferential center side. Near position A, the axial width between the tip of the peak 66 and the tip of the valley 67 is constant (Wa). Furthermore, as shown in Figure 6, at position C in Figure 2, neither the peak 66 nor the valley 67 are formed, and the closing portion 65 is flat. This allows the closing portion 65 to expand and contract easily without interfering with the annular portion 52 of the core metal 51.

[0028] Furthermore, the axial width between the tip of the peak portion 66 and the tip of the valley portion 67 may be a shape that gradually widens from the circumferential end to the circumferential center of the closing portion 65. Also, the axial width between the tip of the peak portion 66 and the tip of the valley portion 67 may be varied depending on the radial position of the closing portion 65.

[0029] The following describes modified embodiments of the present invention. Some descriptions of the same configuration as the above-described embodiments will be omitted. Figure 8 is a partially enlarged view showing the same area as in Figure 7 of a sealing member for a rolling bearing according to a modified embodiment of the present invention. In this example, the peaks 66 and valleys 67 of the closing portion 65 are formed in an annular shape such that the ridges follow the outer edge of the elongated hole 55. That is, as shown in Figure 8 in particular for the valley 67, the two ridges of the valley 67, which extend in the circumferential direction and are at different radial positions, are connected by arc-shaped ridges extending radially from both ends in the circumferential direction. The peaks 66 have a similar structure. The annularly formed peaks 66 and valleys 67 are alternately continuous in the direction toward the outer edge of the elongated hole 55.

[0030] With the above configuration, even if the volume of gas inside the rolling bearing 10 changes due to temperature changes or the like, the closing portion 65 of the seal member 50 expands and contracts, absorbing fluctuations in the pressure inside the rolling bearing 10 and maintaining the pressure at a nearly constant level. In particular, because the closing portion 65 has a bellows structure, pressure fluctuations can be suppressed even when the volume change of gas inside the rolling bearing 10 is large. Furthermore, since the pressure of the rolling bearing can be adjusted without providing ventilation holes or the like in the seal member 50, it is possible to prevent foreign matter from entering the bearing and leakage of lubricants such as grease from inside the bearing. In addition, by integrating the closing portion 65 with the elastic seal material 60, the manufacturing of the seal member 50 becomes easier.

[0031] It should be noted that the present invention is not limited to the embodiments illustrated above, and can be modified as appropriate without departing from the spirit of the invention. In particular, when the closing portion 65 has a bellows structure, the peaks 66 and valleys 67 only need to be alternately continuous, for example, the peaks 66 and valleys 67 may be alternately continuous in the circumferential direction. Also, the hole formed in the annular portion 52 is not limited to the shape of the elongated hole 55. Furthermore, in the above embodiment, the seal member 50 is provided at both axial ends of the rolling bearing 10, but the seal member 50 according to the present invention may be provided at one axial end, and any seal member without a closing portion 65 may be used at the other axial end. Moreover, in this embodiment, the rolling bearing 10 is a ball bearing, but the seal member 50 may be applied to a roller bearing or the like.

[0032] As described above, the following matters are disclosed in this specification: (1) Having an annular core and an elastic sealing material fixed to the core, The core metal includes an annular portion and has at least one hole that penetrates the annular portion in the axial direction. The elastic sealing material has a closing portion provided to close the hole, The closing portion has at least one peak and / or valley that protrudes in the axial direction. A sealing member for rolling bearings, characterized by the above. This configuration allows the pressure inside the rolling bearing to remain nearly constant by absorbing pressure fluctuations at the closed section in response to volume changes in the gas inside the rolling bearing, mainly due to temperature changes. It also prevents foreign matter from entering the rolling bearing and prevents lubricant from leaking out of the rolling bearing.

[0033] (2) The closed section has a bellows structure in which peaks and valleys alternately continue. A sealing member for a rolling bearing as described in (1), characterized in that... With this configuration, by providing a bellows-like structure in the closure section, the closure section becomes more flexible in expanding and contracting, making it easier to absorb pressure fluctuations.

[0034] (3) The holes are a plurality of elongated holes provided in the annular portion of the core metal and extending along the circumferential direction. A sealing member for a rolling bearing according to (1) or (2), characterized in that... This configuration allows for a larger area to be secured in the closed section, making it easier to absorb pressure fluctuations within the closed section.

[0035] (4) The area of ​​the closed portion, as viewed from the axial direction, is formed to be larger than the area of ​​the hole. A sealing member for a rolling bearing as described in any one of (1) to (3), characterized by the above. This configuration allows the occluded section to expand and contract more easily, making it easier to absorb pressure fluctuations within the occluded section.

[0036] (5) The peaks and valleys are formed such that the axial width between the tip of the peak and the tip of the valley on the circumferential central side of the closed portion is wider than the axial width between the tip of the peak and the tip of the valley on the circumferential end side of the closed portion. A sealing member for a rolling bearing according to (3) or (4), characterized in that... With this configuration, the closure portion does not interfere with the annular portion of the core metal, making expansion and contraction easier.

[0037] (6) Outer ring and, Insider, A plurality of rolling elements are arranged to roll freely between the outer ring and the inner ring, A sealing member for a rolling bearing, which is fixed to one of the outer ring and the inner ring and slides against the other, thereby sealing the internal space between the outer ring and the inner ring, A rolling bearing equipped with, The aforementioned sealing member for rolling bearings is a sealing member for rolling bearings described in any one of (1) to (5). A rolling bearing characterized by the following. This configuration allows for the use of a sealing member that can maintain a constant internal pressure in the rolling bearing, thereby maintaining a constant contact pressure between the sealing member and the sliding contact portion of the inner or outer ring. Furthermore, by preventing foreign matter from entering the bearing and preventing lubricant leakage, the lifespan of the rolling bearing can be extended. [Explanation of symbols]

[0038] 10 Rolling bearings 20 Outer ring 21 Outer ring raceway surface 22 Seal locking groove 23 Side wall 30 Inner circle 31 Inner ring raceway surface 32 Sliding surface 33 Side wall 40 Rolling element 45 Retainer 50 Bearing seal member (seal member) 51 Mandrel 52 Annular section 53 Slope 54 Rim section 55 long hole 55a, 55b Inner surface 60 Elastic sealing material 61 Base 62 Outer edge 62a Protrusion 63 Seal Lip 64 Grease Lip 65 Occlusion 66 Yamabe 67 Tanibe 68 Connection part 100 interior spaces Positions A, B, and C Wa,Wb pieces

Claims

1. It has an annular core and an elastic sealing material fixed to the core, The core metal includes an annular portion and has at least one hole that penetrates the annular portion in the axial direction. The elastic sealing material has a closing portion provided to close the hole, The closing portion has at least one peak and / or valley that protrudes in the axial direction. A sealing member for rolling bearings, characterized by the above.

2. The aforementioned closure section has a bellows structure in which peaks and valleys alternately continue. A sealing member for a rolling bearing according to claim 1, characterized in that...

3. The aforementioned holes are a plurality of elongated holes provided in the annular portion of the core metal, extending along the circumferential direction. A sealing member for a rolling bearing according to claim 2, characterized in that...

4. The area of ​​the closed portion, as viewed from the axial direction, is formed to be larger than the area of ​​the hole. A sealing member for a rolling bearing according to claim 2, characterized in that...

5. The peaks and valleys are formed such that the axial width between the tip of the peak and the tip of the valley on the circumferential central side of the closed portion is wider than the axial width between the tip of the peak and the tip of the valley on the circumferential end side of the closed portion. A sealing member for a rolling bearing according to claim 3, characterized in that...

6. Outer ring and, Insider, A plurality of rolling elements are arranged to roll freely between the outer ring and the inner ring, A sealing member for a rolling bearing, which is fixed to one of the outer ring and the inner ring and slides against the other, thereby sealing the internal space between the outer ring and the inner ring, A rolling bearing equipped with, The rolling bearing seal member is the rolling bearing seal member described in any one of claims 1 to 5. A rolling bearing characterized by the following.

Images