JP6981143B2 - Ball bearing with seal - Google Patents

Description

The present invention relates to a ball bearing with a seal.

Conventionally, rolling bearings incorporating a contact-type seal have been known to reduce the tightening allowance of the seal by lightly contacting the seal only when a preload is applied, and to reduce the rotational torque due to the frictional resistance of the seal. (See Patent Document 1). Further, Patent Document 2 describes a rolling bearing provided with a non-contact type seal having a gap between the inner ring and the seal lip portion, eliminating friction between the inner ring and the seal, and ensuring a certain level of dustproof performance. ing.

Japanese Patent No. 3948477 Japanese Patent No. 5636819

However, the rolling bearing described in Patent Document 1 has a problem that the sealing property is lower than that of a normal contact type seal because the tightening allowance of the seal is reduced. Further, even in the rolling bearing described in Patent Document 2, since it is a non-contact type seal, the sealing property is low.

The present invention has been made in view of the above-mentioned problems, and an object thereof is a ball bearing with a seal capable of reducing the torque of the seal and ensuring the sealing property without reducing the tightening allowance of the seal. Is to provide.

The above object of the present invention is achieved by the following configuration.
(1) An outer ring having an outer ring raceway groove formed on the inner peripheral surface, an inner ring having an inner ring raceway groove formed on the outer peripheral surface, and a rollable arrangement between the outer ring raceway groove and the inner ring raceway groove. A ball bearing with a seal comprising a plurality of balls, a cage that rotatably holds the plurality of balls, and at least one sealing member that seals an axial opening between the outer ring and the inner ring. And,
The sealing member includes an annular core metal and an annular elastic body fixed to the core metal.
The elastic body has a lip support portion extending inward in the radial direction from the inner peripheral edge of the core metal and having a seal lip on the inner diameter side portion which is in sliding contact with the seal groove of the inner ring.
The lip support portion is on the core metal side with respect to the radial intermediate position between the tip of the seal lip and the inner peripheral edge of the core metal, and the axial wall thickness is larger than the wall thickness of the other portion of the lip support portion. Has a thin thin wall,
A ball bearing with a seal, wherein the diameter of the inner peripheral edge of the core metal is larger than the pitch circle diameter of the ball.

According to the ball bearing with a seal of the present invention, the sealing member includes an annular core metal and an annular elastic body fixed to the core metal, and the elastic body is radially from the inner peripheral edge of the core metal. It has a lip support portion that extends inward and has a seal lip that slides into the seal groove of the inner ring on the inner diameter side portion, and the lip support portion is located at a radial intermediate position between the tip of the seal lip and the inner peripheral edge of the core metal. On the other hand, the core metal side has a thin portion whose axial wall thickness is thinner than the wall thickness of the other portion of the lip support portion, and the diameter of the inner peripheral edge of the core metal is larger than the pitch circle diameter of the ball. As a result, the lip support portion is easily deformed, and the frictional resistance of the seal lip can be reduced while ensuring the tightening allowance between the seal groove of the inner ring and the seal lip to maintain the sealing property.

It is the main part vertical sectional view of the ball bearing with a seal. It is an enlarged sectional view of the seal member shown in FIG.

Hereinafter, a ball bearing with a seal according to an embodiment of the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, the ball bearing 10 with a seal of the present embodiment has an outer ring 11, an inner ring 12, a plurality of balls 13 which are rolling elements, and a cage 14 that rotatably holds the plurality of balls 13. And a pair of sealing members 20.

An outer ring raceway groove 15 is formed on the inner peripheral surface of the outer ring 11, and a seal locking groove 16 for fixing the seal member 20 is formed on both sides in the axial direction. An inner ring raceway groove 17 is formed on the outer peripheral surface of the inner ring 12, and seal grooves 18 are formed on both sides in the axial direction.

Between the outer ring raceway groove 15 and the inner ring raceway groove 17, a plurality of balls 13 arranged at equal intervals in the circumferential direction and rotatably held by the cage 14 are arranged. A pair of sealing members 20 for externally sealing the sealed ball bearing 10 in cooperation with the sealing groove 18 are arranged on both sides in the axial direction between the outer ring 11 and the inner ring 12 to seal the axial opening. ..

The seal member 20 prevents grease (not shown) enclosed in the sealed ball bearing 10 from leaking to the outside, and also prevents foreign matter (for example, water, muddy water, dust, etc.) outside the sealed ball bearing 10 from leaking to the outside. ) Invades the inside.

With reference to FIG. 2, the sealing member 20 is made of an annular core metal 21 formed of a metal plate such as a steel plate having a substantially L-shaped cross section and an elastic material such as rubber, and is fixed to the core metal 21. It has an elastic body 22 and.

The core metal 21 has a cylindrical portion 23 and a disk portion 24 formed by bending inward in the radial direction from one end in the axial direction of the cylindrical portion 23. The diameter D of the inner peripheral edge 24a of the disk portion 24 is larger than the pitch circle diameter PCD of the ball bearing 10 with a seal.

The elastic body 22 has an outer peripheral edge portion 26 formed by covering the outer peripheral surface of the cylindrical portion 23 of the core metal 21 and bulging outward in the radial direction, and an annular shape extending inward in the radial direction from the inner peripheral edge portion 24a of the core metal 21. Has a lip support portion 27 and a side portion 28 fixed to the outer surface 25 of the core metal 21 and connecting the outer peripheral edge portion 26 and the lip support portion 27.

The outer peripheral edge portion 26 of the elastic body 22 is locked to the seal locking groove 16 formed at the axial end portion of the outer ring 11 by press fitting or the like, and the seal member 20 is fixed to the outer ring 11.

The lip support portion 27 is inclined inward in the axial direction as it goes inward in the radial direction from the inner peripheral edge 24a of the core metal 21, and the seal lip 29 projects inward in the axial direction on the inner diameter side portion of the lip support portion 27. It is formed.

The seal lip 29 is in sliding contact with the axially outward side wall surface 18a of the seal groove 18 provided at the axial end of the inner ring 12. A grease lip 30 projecting inward in the axial direction is formed on the inner surface of the lip support portion 27 on the outer side in the radial direction from the seal lip 29. The grease lip 30 is arranged so as to face the side wall surface 18a of the seal groove 18 in close proximity to the side wall surface 18a.

Further, the lip support portion 27 includes a thin portion 31 whose axial wall thickness t is thinner than the wall thickness of the other portion of the lip support portion 27. The thin portion 31 is provided on the core metal 21 side of the radial intermediate position CP between the radial tip 29a of the seal lip 29 and the inner peripheral edge 24a of the core metal 21. The thin wall portion 31 is formed in a substantially arcuate cross section in which the inner side surface is recessed outward in the axial direction, and the outer surface is formed in a straight cross section, so that the wall thickness t is thin.

That is, when the seal member 20 is mounted on the ball bearing 10 with a seal, the thin-walled portion 31 has a substantially arcuate cross section on the side where the lip support portion 27 is deformed outward in the axial direction due to the tightening margin of the seal member 20 and stretches. There is, and the opposite side has a straight cross section. By forming the inner side surface of the thin-walled portion 31 in a substantially arcuate cross section, it is possible to reliably prevent the lip support portion 27 from interfering with the cage 14.

In this way, the inner diameter of the core metal 21 is increased to lengthen the radial length of the lip support portion 27, the thin wall portion 31 is provided on the lip support portion 27, and the thin wall portion 31 to the seal lip 29 in the radial direction. By setting a long distance to the tip 29a to facilitate deformation of the lip support portion 27, it is possible to reduce the frictional resistance and reduce the torque without reducing the seal tightening allowance for the seal groove 18.

In order to effectively achieve the above object and prevent interference with the cage 14, the length L1 from the inner peripheral edge 24a of the core metal 21 to the thin-walled portion 31 and the seal lip 29 from the thin-walled portion 31 to the thin-walled portion 31. The ratio to the length L2 up to the radial tip 29a is preferably smaller than 1: 1, more preferably larger than 1: 3, and even more preferably larger than 1: 2.

Further, the lip support portion 27, that is, from the inner peripheral edge 24a of the core metal 21 to the radial tip 29a of the seal lip 29 may be composed of only an elastic material. As a result, the frictional resistance is small, the torque is low, and the sealing performance equivalent to that of a normal contact seal can be ensured.

Further, since the lip support portion 27 is easily deformed, the tightening force of the seal lip 29 tends to be weak, but in order to improve the sealing performance, the side surface portion 29b of the seal lip 29 on the inner ring raceway groove 17 side is formed on the inner ring 12. It is preferable that the seal groove 18 is brought into sliding contact with the side wall surface 18a.

Further, the grease lip 30 suppresses the enclosed grease from flowing out to the seal groove 18, but in order to reduce frictional resistance, the grease lip 30 does not come into contact with the seal groove 18 of the inner ring 12 and is arranged with a gap. It is desirable to be done.

Further, the core metal 21 has an L-shaped cross section, which is a simple shape capable of reducing the manufacturing cost, and the outer peripheral edge portion 26 does not include the core metal 21 in consideration of mountability to the seal locking groove 16. It is desirable to do so.

As described above, according to the ball bearing 10 with a seal of the present embodiment, the seal member 20 includes an annular core metal 21 and an annular elastic body 22 fixed to the core metal 21. The elastic body 22 has a lip support portion 27 having a seal lip 29 extending inward in the radial direction from the inner peripheral edge 24a of the core metal 21 and sliding in contact with the seal groove 18 of the inner ring 12 on the inner diameter side portion. In 27, the thickness t in the axial direction is the thickness of the other part of the lip support portion 27 on the core metal 21 side with respect to the radial intermediate position CP between the tip 29a of the seal lip 29 and the inner peripheral edge 24a of the core metal 21. It has a thinner thin portion 31. As a result, the lip support portion 27 is easily deformed, and the frictional resistance between the seal lip 29 and the seal groove 18 is reduced while ensuring the tightening allowance between the seal groove 18 of the inner ring 12 and the seal lip 29 to maintain the sealing property. can do.

Further, since the diameter D of the inner peripheral edge 24a of the core metal 21 is larger than the pitch circle diameter PCD of the ball 13, the radial length of the lip support portion 27 can be set long, and the sealing force can be further reduced.

The present invention is not limited to the above-described embodiment, and can be appropriately modified, improved, and the like.

10 Ball bearing with seal 11 Outer ring 12 Inner ring 13 Ball 14 Cage 15 Outer ring raceway groove 17 Inner ring raceway groove 18 Seal groove 20 Seal member 21 Core metal 22 Elastic body 24a Inner peripheral edge of core metal 27 Lip support 29 Seal lip 29a Seal lip Radial tip 31 Thin wall CP Radial intermediate position D Diameter of inner peripheral edge of core metal PCD Pitch circle diameter t Axial wall thickness

Claims (2)

An outer ring having an outer ring raceway groove formed on the inner peripheral surface, an inner ring having an inner ring raceway groove formed on the outer peripheral surface, and a plurality of balls freely arranged between the outer ring raceway groove and the inner ring raceway groove. A ball bearing with a seal, comprising a cage that rotatably holds the plurality of balls, and at least one sealing member that seals an axial opening between the outer ring and the inner ring. ,
The sealing member includes an annular core metal and an annular elastic body fixed to the core metal.
The elastic body has a lip support portion extending inward in the radial direction from the inner peripheral edge of the core metal and having a seal lip on the inner diameter side portion which is in sliding contact with the seal groove of the inner ring.
The lip support portion is on the core metal side with respect to the radial intermediate position between the tip of the seal lip and the inner peripheral edge of the core metal, and the axial wall thickness is larger than the wall thickness of the other portion of the lip support portion. Has a thin thin wall,
A ball bearing with a seal, wherein the diameter of the inner peripheral edge of the core metal is larger than the pitch circle diameter of the ball. The ball bearing with a seal according to claim 1, wherein the thin-walled portion is formed in a substantially arcuate cross section in which the inner side surface is recessed outward in the axial direction and the outer surface is formed in a straight cross section.

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