JP2019060441A - Ball bearing with seal - Google Patents

Abstract

To provide a ball bearing with a seal capable of reducing torque of the seal, and capable of securing sealing performance without reducing the interference of the seal.SOLUTION: A 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 includes a lip support part 27 which extends toward a radial inner side from an inner peripheral edge 24a of the core metal 21 and has a seal lip 29 slidably abutted to a seal groove 18 of an inner ring 12 in an internal diameter side portion. The lip support part 27 has a thin part 31 having an axial thickness t thinner than the thickness of other portions of the lip support part 27 on the core metal 21 side with respect to a radial intermediate position CP between an end 29a of the seal lip 29 and the inner peripheral edge 24a of the core metal 21.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a sealed ball bearing.

  Conventionally, as a rolling bearing incorporating a contact type seal, one is known in which the seal interference is reduced by bringing the seal into light contact only at the time of preload load, and rotational torque is reduced due to the frictional resistance of the seal. (See Patent Document 1). Further, Patent Document 2 describes a rolling bearing having a non-contact type seal having a gap between an inner ring and a seal lip, eliminating friction between the inner ring and the seal and securing a certain dustproof performance. ing.

Patent No. 3948477 gazette Patent No. 5636819 gazette

  However, in the rolling bearing described in Patent Document 1, there is a problem that the sealing performance is lower than that of a normal contact type seal because the interference of the seal is reduced. Moreover, also in the rolling bearing described in Patent Document 2, since the seal is a noncontact seal, the sealing property is low.

  The present invention has been made in view of the above-described problems, and an object thereof is to reduce the torque of the seal and to provide a seal ball bearing capable of securing the sealability without reducing the interference of the seal. To provide.

The above object of the present invention is achieved by the following constitution.
(1) The outer ring having the outer ring raceway groove formed on the inner peripheral surface, the inner ring having the inner ring raceway groove formed on the outer peripheral surface, and the roll ring disposed between the outer ring raceway groove and the inner ring raceway groove Sealed ball bearing comprising: a plurality of balls; a cage rotatably holding the plurality of balls; and at least one seal member sealing the axial opening between the outer ring and the inner ring And
The seal 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 radially inward from the inner peripheral edge of the cored bar and having, at an inner diameter side portion, a seal lip slidably contacting the seal groove of the inner ring,
The lip supporting portion is closer to the cored metal with respect to the radial intermediate position between the tip of the seal lip and the inner peripheral edge of the cored bar, and the axial thickness is greater than the thickness of the other portion of the lip supporting portion Has a thin thin part,
A sealed ball bearing characterized in that a diameter of an inner peripheral edge of the cored bar is larger than a diameter of a pitch circle of the ball.

  According to the sealed ball bearing of the present invention, the seal member includes an annular core metal and an annular elastic body fixed to the core metal, and the elastic body extends radially from the inner peripheral edge of the core metal. The lip support has an inwardly extending seal lip having a seal lip in sliding contact with the seal groove of the inner ring in the inner diameter side portion, and the lip support is at a radially intermediate position between the tip of the seal lip and the inner peripheral edge of the core. On the other hand, on the core metal side, there is a thin-walled portion whose axial thickness is thinner than the thickness of the other part of the lip support, 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 supporting portion is easily deformed, and it is possible to reduce the frictional resistance of the seal lip while maintaining the sealing performance by securing the interference between the seal groove of the inner ring and the seal lip.

It is a principal part longitudinal cross-sectional view of a ball bearing with a seal. It is an expanded sectional view of the seal member shown in FIG.

Hereinafter, a sealed ball bearing according to an embodiment of the present invention will be described in detail based on the drawings.
As shown in FIG. 1, the sealed ball bearing 10 of the present embodiment is a cage 14 that holds the outer ring 11, the inner ring 12, the plurality of balls 13 as rolling elements, and the plurality of balls 13 in a rolling manner. And a pair of seal 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 by the cage 14 and rotatably held are disposed. A pair of seal members 20 for sealing the sealed ball bearing 10 from the outside in cooperation with the seal groove 18 is disposed on both axial sides between the outer ring 11 and the inner ring 12 to seal the axial opening. .

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

  Referring also to FIG. 2, seal member 20 is an annular core metal 21 formed in a substantially L-shaped cross section by a metal plate such as a steel plate, and an annular material fixed to core metal 21 and made of an elastic material such as rubber. And an elastic body 22 of

  The cored bar 21 has a cylindrical portion 23 and a disc portion 24 bent radially inward from one end of the cylindrical portion 23 in the axial direction. The diameter D of the inner peripheral edge 24 a of the disk portion 24 is larger than the pitch circle diameter PCD of the sealed ball bearing 10.

  The elastic body 22 covers an outer peripheral surface of the cylindrical portion 23 of the cored bar 21 and is formed to expand radially outward, and an annular ring extending radially inward from the inner peripheral edge 24 a of the cored bar 21. And a side portion 28 fixed to the outer surface 25 of the metal core 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 engaged with the seal engagement groove 16 formed at the axial direction end 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 27 extends inward in the axial direction as it extends radially inward from the inner peripheral edge 24 a of the core metal 21, and the seal lip 29 projects axially inward at the inner diameter side of the lip support 27. It is formed.

  The seal lip 29 is in sliding contact with the axially outward side wall surface 18 a of the seal groove 18 provided at the axial end of the inner ring 12. A grease lip 30 projecting axially inward is formed on the inner surface radially outward of the seal lip 29 of the lip support 27. The grease lip 30 is disposed in close proximity to the side wall surface 18 a of the seal groove 18.

  In addition, the lip support 27 includes a thin portion 31 whose axial thickness t is thinner than the thickness of the other portion of the lip support 27. The thin portion 31 is provided closer to the core metal 21 than a radially intermediate position CP of the radial tip end 29 a of the seal lip 29 and the inner peripheral edge 24 a of the core metal 21. The thin-walled portion 31 is formed in a substantially arc-shaped cross section in which the inner side surface is recessed outward in the axial direction, and the outer side surface is formed linearly in a cross-sectional shape, thereby reducing the thickness t.

  That is, when the sealing member 20 is attached to the sealed ball bearing 10, the thin portion 31 has a substantially arc-shaped cross section on the side where the lip supporting portion 27 is deformed outward in the axial direction by the interference of the sealing member 20 Yes, the opposite side is straight in cross section. By forming the inner side surface of the thin portion 31 into a substantially arc shape in cross section, interference between the lip support 27 and the holder 14 can be reliably prevented.

  Thus, the inner diameter of the core metal 21 is increased, and the radial length of the lip support 27 is increased, and the thin portion 31 is provided on the lip support 27, and the radial direction of the seal lip 29 from the thin portion 31. By setting the distance to the tip 29a long to make the lip support 27 easy to deform, it is possible to reduce the frictional resistance and reduce the torque without reducing the seal interference with the seal groove 18.

  In order to achieve the above object effectively and to prevent interference with the cage 14, the length L 1 from the inner peripheral edge 24 a of the metal core 21 to the thin portion 31 and the thin portion 31 to the seal lip 29 Is preferably smaller than 1: 1, more preferably larger than 1: 3, and still more preferably larger than 1: 2.

  Further, it is preferable that the lip supporting portion 27, that is, the inner peripheral edge 24 a of the core metal 21 to the radial direction end 29 a of the seal lip 29 be made of only an elastic material. As a result, the frictional resistance is small and the torque is low, and the sealing performance equivalent to that of a normal contact seal can be secured.

  In addition, since the lip support 27 tends to be deformed, the tightening force of the seal lip 29 also tends to be weak. However, to improve the sealing performance, the side portion 29b of the inner ring raceway groove 17 side of the seal lip 29 It is preferable that the side wall surface 18 a of the seal groove 18 be in sliding contact.

  Also, although the grease lip 30 suppresses the flow of the enclosed grease into the seal groove 18, it is not in contact with the seal groove 18 of the inner ring 12 to reduce the frictional resistance, and is disposed with a gap. It is desirable to be done.

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

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

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

  The present invention is not limited to the above-described embodiment, and appropriate modifications, improvements, and the like can be made.

DESCRIPTION OF SYMBOLS 10 seal ball bearing 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 periphery of metal core 27 lip support 29 seal lip 29a seal lip Radial tip 31 Thin-walled part CP Radial intermediate position D Inner peripheral diameter of core metal PCD Pitch circle diameter t Axial thickness

Claims (1)

An outer ring having an outer ring raceway groove formed on an inner peripheral surface, an inner ring having an inner ring raceway groove formed on an outer peripheral surface, and a plurality of ball balls rollably disposed between the outer ring raceway groove and the inner ring raceway groove A sealed ball bearing comprising: a holder rotatably holding the plurality of balls; and at least one seal member sealing an axial opening between the outer ring and the inner ring. ,
The seal 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 radially inward from the inner peripheral edge of the cored bar and having, at an inner diameter side portion, a seal lip slidably contacting the seal groove of the inner ring,
The lip supporting portion is closer to the cored metal with respect to the radial intermediate position between the tip of the seal lip and the inner peripheral edge of the cored bar, and the axial thickness is greater than the thickness of the other portion of the lip supporting portion Has a thin thin part,
A sealed ball bearing characterized in that a diameter of an inner peripheral edge of the cored bar is larger than a diameter of a pitch circle of the ball.

Images