JP2007315459A - Bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device in which eccentric wear hardly occurs in a seal lip of an elastic part, oil leakage hardly occurs, and rotational torque is hardly increased. <P>SOLUTION: A seal member 4 is composed of a core bar 41 and the elastic part 42 fixed to the core bar 41. A main lip 50 for sealing the seal member 4 and the second outer peripheral face 32 of an inner ring 2 constantly in the radial direction is formed at the elastic part 42. Further, an auxiliary lip 51 is formed at the elastic part 42 which is not in contact with the inner ring 2 when there is no pressure from the outside, and which seals the seal member 4 and a step 31 of the inner ring 2 in the axial direction when pressure M is applied from the outside. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a bearing device, and more particularly, to a bearing device that is suitable if it is disposed in a transmission or a crank of a motorcycle or an ATV.

  Conventionally, as a bearing device, there is one described in JP-A-7-332379 (Patent Document 1).

  The bearing device includes an outer ring, an inner ring, a rolling element disposed between the outer ring and the inner ring, and a seal member disposed between an inner peripheral surface of the outer ring and an outer peripheral surface of the inner ring.

  The seal member includes a cored bar part and an elastic part that covers the cored bar. The seal member has a fixed side on the outer diameter side and a free end side on the inner diameter side, and a tightening margin is set between the end portion on the free end side and the inner ring. Specifically, the seal member is fitted with an end on the outer diameter side in a mounting groove provided on the inner periphery of the outer ring, and an end on the inner diameter side faces a seal groove provided on the outer peripheral surface of the inner ring, The raceway surface is sealed with respect to the outside by bringing the seal lip of the elastic portion into sliding contact with the side wall of the seal groove.

  In the bearing device, the inner diameter of the cored bar is made smaller than the outer diameter of the inner ring raceway shoulder, so that the deformation of the seal lip is suppressed and the raceway surfaces of the inner and outer rings are reliably sealed to the outside. Like to do.

However, in the above bearing device, when the hydraulic pressure outside the bearing is high, there is a problem that the force when the seal lip is pressed against the side wall of the seal groove becomes excessive, and the lip portion is liable to be unevenly worn. There is a problem that external oil enters the bearing device. Further, when the hydraulic pressure outside the bearing is high, there is a problem that the force with which the seal lip is pressed against the side wall of the seal groove becomes excessive, and the rotational torque of the bearing device is large.
Japanese Patent Laid-Open No. 7-332379 (FIG. 1)

  Accordingly, an object of the present invention is to provide a bearing device in which the seal lip of the elastic portion is less likely to be unevenly worn, oil leakage is unlikely to occur, and the rotational torque is not likely to increase.

In order to solve the above problems, the bearing device of the present invention is
A first race ring having a first raceway surface;
A second raceway having a second raceway surface, a circumferential surface, and a step portion located between the second raceway surface and the circumferential surface;
A rolling element disposed between the first raceway surface of the first raceway and the second raceway surface of the second raceway;
A seal member having one end attached to the first raceway ring,
The sealing member is
A cored bar,
It has an elastic part attached to this mandrel part,
The elastic part is
A main lip that extends substantially in the radial direction of the second raceway and contacts the peripheral surface of the second raceway surface;
When no pressure is applied from the outside in the axial direction, the stepped portion faces the stepped portion at an interval in the axial direction, and when pressure is applied from the outside in the axial direction, a secondary lip that contacts the stepped portion It is characterized by having.

  According to the present invention, the main lip of the elastic portion extends substantially in the radial direction of the second track ring and comes into contact with the peripheral surface of the second track ring. Even when a large pressure is applied and the seal member is elastically deformed so that the other end of the seal member is displaced inward in the axial direction, the tightening allowance between the main lip and the second race ring is greatly changed. There is no. Therefore, since the frictional force between the second race and the main lip does not become excessive, the main lip portion is less likely to cause uneven wear, and oil leakage is less likely to occur. Further, even if a large pressure is applied from the outside, the frictional force between the second race and the main lip does not increase, so that the rotational torque does not increase.

  Further, according to the present invention, the secondary lip is opposed to the stepped portion with a gap in a state where no pressure is applied in the axial direction from the outside and a large sealing capacity is not required. Lip wear can be suppressed and rotational torque can be reduced.

  Further, according to the present invention, the sub lip is subjected to greater pressure from the outside inward in the axial direction, and the seal member is elastic so that the other end side of the seal member is displaced inward in the axial direction. Since it contacts the step when deformed, it can increase the ability of the seal and reliably prevent oil leakage when a greater pressure is applied in the axial direction from the outside. Can do.

  According to the sealing device of the present invention, the main lip extends substantially in the radial direction of the second race ring and comes into contact with the peripheral surface of the second race ring, so that a large pressure is applied from the outside. Even if the sealing member is elastically deformed so that the other end side of the sealing member is displaced inward in the axial direction by acting, the tightening allowance between the main lip and the second bearing ring does not change greatly, and the second The frictional force between the race and the main lip will not be excessive. Therefore, the main lip portion is less likely to cause uneven wear, oil leakage is less likely to occur, and the rotational torque does not increase.

  Further, according to the sealing device of the present invention, the secondary lip is opposed to the stepped portion with a gap in a state where no pressure is applied in the axial direction from the outside and a large sealing capability is not required. Therefore, the wear of the auxiliary lip can be suppressed and the rotational torque can be reduced.

  According to the sealing device of the present invention, when the sub lip is subjected to a greater pressure in the axial direction from the outside, and the seal member is elastically deformed so that the other end side of the seal member is displaced inward in the axial direction. Therefore, when a greater pressure is applied in the axial direction from the outside, oil leakage can be reliably prevented.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a sectional view in the axial direction of a bearing device when no pressure is applied in the axial direction from the outside of an embodiment of the present invention. FIG. 3 is a cross-sectional view of the bearing device in the axial direction when pressure is applied in the axial direction from the outside of the embodiment of the present invention.

  This bearing device is used in an environment where the external hydraulic pressure is high, such as a transmission or a crank of a two-wheeled vehicle, and an installed rotary shaft rotates at high speed. 1 and 3 indicate directions in which hydraulic pressure acts.

  As shown in FIG. 1, this bearing device includes an outer ring 1 as a first bearing ring, an inner ring 2 as a second bearing ring, a ball 3 as an example of a rolling element, and one axial direction of the outer ring 1. A seal member 4 is provided between the one end portion and the one end portion on the one side in the axial direction of the inner ring 2.

  The outer ring 1 is fitted in an inner peripheral surface of a housing (not shown) such as a transmission or a crank of a motorcycle. The outer ring 1 has a raceway groove 15 as a first raceway surface and a mounting groove 16 on one side of the raceway groove 15 in the axial direction. On the other hand, the inner ring 2 is externally fitted to a rotating shaft (not shown). The inner ring 2 includes a raceway groove 25 as a second raceway surface, a first outer circumference surface 30 adjacent to the raceway groove 25 in the axial direction, and a second outer circumference surface connected to the first outer circumference surface 30 via a step portion 31. 32. The second outer peripheral surface 32 is polished. The step 31 is located between the first outer peripheral surface 30 and the second outer peripheral surface 32 as an example of the peripheral surface. The axially outer end face of the step portion 31 has a substantially conical shape whose diameter decreases in accordance with the line outward in the axial direction. A plurality of the balls 3 are arranged between the raceway groove 15 of the outer ring 1 and the raceway groove 25 of the inner ring 2 with a predetermined interval in the circumferential direction while being held by the cage 5.

  The seal member 4 includes a metal cored bar 41 and a rubber elastic part 42. The elastic part 42 is fixed to the cored bar part 41 by means such as pressure bonding, baking, or adhesion. One end side in the radial direction of the seal member 4 is fitted and fixed in the mounting groove 16 of the outer ring 1, while the other end side in the radial direction of the seal member 4 is slid with respect to the inner ring 2. It comes to move. The elastic part 42 is fixed to the cored bar part 41 so as to surround both ends of the cored bar part 41 in the radial direction and to cover the entire outer end face of the cored bar part 41 in the axial direction. In other words, the elastic portion 42 is disposed so as to cover a portion other than the central portion of the inner end face in the axial direction of the cored bar portion 41. The seal member 4 blocks one axial opening between the outer ring and the inner ring, thereby preventing oil from entering the bearing from the outside in one axial direction.

  FIG. 2 is an enlarged cross-sectional view of the vicinity of the other end side (sliding portion) of the seal member 4 of the bearing device when no pressure is applied in the axial direction from the outside. FIG. 4 is an enlarged cross-sectional view of the vicinity of the other end side (sliding portion) of the seal member 4 of the bearing device when pressure is applied in the axial direction from the outside.

  As shown in FIG. 2, on the other end side of the seal member 4, the inner diameter of the inner end surface in the radial direction of the cored bar 41 is larger than the outer diameter of the first outer peripheral surface 30 adjacent to the track shoulder of the inner ring 2. Is also getting smaller. Further, at the other end of the seal member 4, the cored bar 41 is bent inward in the axial direction, and the tip of the cored bar 41 is radially inward and axially inward. 2 It extends so as to be inclined obliquely with respect to the normal direction of the outer peripheral surface 32. In this way, the cored bar part 41 is extended inward in the radial direction, and the distal end part of the cored bar part 41 is bent inward in the axial direction, whereby the rigidity of the cored bar part 41 is increased.

  The elastic portion 42 has a block-shaped portion 44 that covers the entire outer surface of the distal end portion of the cored bar portion 41 on the other end side of the seal member 4. A main lip 50 and a sub lip 51 are formed in the block-shaped portion 44. The main lip 50 is located inward in the radial direction of the block-shaped portion 44. The main lip 50 protrudes radially inward toward the second outer peripheral surface 32 of the inner ring 2 and substantially extends in the circumferential direction along an annular block-shaped portion 44. The main lip 50 is always in contact with the second outer peripheral surface 32 of the inner ring 2 over the entire circumference, and seals between the seal member 4 and the second outer peripheral surface 32. To slide. The main lip 50 is located outward in the axial direction from the radially inner end face of the cored bar 41. In this way, even if a high pressure acts on the main lip 50 from the outside in the axial direction, the main lip 50 is prevented from reversing inward in the axial direction.

  On the other hand, the sub lip 51 is located inside the block-shaped portion 44 in the axial direction. The sub lip 51 protrudes toward the inner step portion 31 in the axial direction, and substantially extends in the circumferential direction along the annular block-shaped portion 44. As shown in FIGS. 1 and 2, the sub lip 51 is opposed to the axial direction with an interval from the step portion 31 when no pressure is applied from the outside toward the inside in the axial direction. When a pressure smaller than a predetermined value is applied inward, the other end of the seal member 4 is displaced inward in the axial direction, and is opposed in the axial direction with a shorter distance from the step portion 31. On the other hand, as shown in FIGS. 3 and 4, when pressure is applied to a predetermined value or more from the outside toward the inside in the axial direction, the step 31 is moved inward in the axial direction by elastic deformation of the seal member 4. The seal member 4 and the step portion 31 are hermetically sealed. The sub lip 51 slides with respect to the step portion 31 when it contacts the step portion 31.

  As pressure is applied from the outside toward the inside in the axial direction, and the pressure decreases from the state in which the sub lip 51 is in contact with the step portion 31, the displacement on the other end side of the seal member 4 is reduced, and the sub lip is reduced. 51 and the stepped portion 31 are not in contact with each other, and when the pressure disappears, the state returns to the original as shown in FIGS.

  According to the bearing device of the above embodiment, since the main lip 50 seals the seal member 4 and the second outer peripheral surface 32 in the radial direction, the seal is generated by the external force (hydraulic pressure) M in the axial direction. Even if the other end side of the seal member 4 is displaced to the ball 3 side due to the elastic deformation of the member 4, the tightening margin between the main lip 50 and the second outer peripheral surface 32 of the inner ring 2 does not increase. Therefore, even if the external pressure from the outside increases, the frictional force between the main lip 50 and the inner ring 2 does not increase, so that uneven wear of the main lip 50 due to friction can be suppressed, and the unevenness of the main lip 50 can be suppressed. Oil leakage due to wear can be suppressed. Further, even if the external pressure from the outside increases, the frictional force between the main lip 50 and the inner ring 2 does not increase. Therefore, unlike the conventional bearing device, the rotational torque rapidly increases even if the external pressure from the outside increases. It doesn't get bigger. Further, the seal between the main lip 50 and the second outer peripheral surface 32 of the inner ring 2 is a radial seal, and the seal with the second outer peripheral surface 32 of the inner ring 2 is on the other end side of the seal member 4. Since the main lip 50 is hardly affected by the displacement and only the rubber elasticity of the main lip 50 is used, the main lip whose sealing force is greatly influenced by the displacement of the other end of the seal member is compared with the structure in which the main lip seals in the axial direction. Rotational torque can be reduced.

  Further, according to the bearing device of the above-described embodiment, the main lip 50 is positioned outward in the axial direction from the radially inner end face of the cored bar portion 41, so that the main lip is ball-shaped by the external pressure M. Inversion to the 3 side can be reliably prevented.

  Further, according to the bearing device of the above embodiment, the sub lip 51 is opposed to the step portion 31 with a gap in a state where no pressure is applied in the axial direction from the outside and a large sealing capability is not required. Thus, the auxiliary lip 51 is not always in contact with the inner ring 2, so that the wear of the auxiliary lip 51 can be suppressed and the rotational torque can be reduced.

  Further, according to the bearing device of the above embodiment, the sub lip 51 is applied with a greater pressure from the outside toward the inside in the axial direction, and the seal member 4 is elastically deformed, whereby the other end side of the seal member 4 is further displaced. When this happens, it will come into contact with the step 31.When a larger pressure is applied from the outside toward the inside in the axial direction, the ability of the seal can be increased, and oil leakage can be ensured. Can be prevented. That is, when an external force (hydraulic pressure) M acts on the seal member 4 and there is a risk of oil leakage, the main lip 50 and the sub lip 51 can cooperate to form a double lip structure. When an external force (hydraulic pressure) M is applied, the sealing performance can be remarkably improved, and oil can be reliably prevented from leaking into the ball 3 side.

  In the bearing device of the above embodiment, the first bearing ring is the outer ring 1 and the second bearing ring is the inner ring 2. However, in the present invention, the first bearing ring is the inner ring, The two race rings may be outer rings. That is, in the bearing device of the above embodiment, one end side of the seal member 4 is fitted and fixed in the mounting groove 16 of the outer ring 1, and the other end side of the seal member 4 slides with respect to the inner ring 2. However, in the present invention, one end side of the seal member may be fitted and fixed to the inner ring, and the other end side of the seal member may slide with respect to the outer ring.

  In the bearing device of the above embodiment, the seal member 4 is provided only on one side in the axial direction of the bearing device. However, in this invention, the seal member is provided on both sides in the axial direction of the bearing device. May be.

  Furthermore, in the bearing device of the above-described embodiment, the elastic portion 42 is fixed to the core metal portion 41 so as to cover the entire outer end surface of the core metal portion 41 in the axial direction. May be arranged so as to cover the entire inner end face in the axial direction of the cored bar part and cover a part other than the central part of the axially outer end face of the cored bar part, or the axis of the cored bar part You may coat the entire end face either inward or outward.

  In the bearing device of the above embodiment, the rolling element is the ball 3, but in the present invention, the rolling element may be a rolling element other than a ball, such as a cylindrical roller or a tapered roller. is there.

It is sectional drawing of the axial direction of the bearing apparatus when the pressure is not applied to the axial direction from the outer side of one Embodiment of this invention. It is an expanded sectional view near the other end side (sliding part) of the seal member of the bearing device of the embodiment when no pressure is applied in the axial direction from the outside. It is sectional drawing of the axial direction of the bearing apparatus when the pressure is applied to the axial direction from the outer side of one Embodiment of this invention. It is an expanded sectional view near the other end side (sliding part) of the seal member of the bearing device of the embodiment when pressure is applied in the axial direction from the outside.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer ring 2 Inner ring 3 Ball 4 Seal member 30 1st outer peripheral surface 31 Step part 32 2nd outer peripheral surface 41 Core metal part 42 Elastic part 44 Block-shaped part 50 Main lip 51 Sub lip

Claims (1)

A first race ring having a first raceway surface;
A second raceway having a second raceway surface, a circumferential surface, and a step portion located between the second raceway surface and the circumferential surface;
A rolling element disposed between the first raceway surface of the first raceway and the second raceway surface of the second raceway;
A seal member having one end attached to the first raceway ring,
The sealing member is
A cored bar,
It has an elastic part attached to this mandrel part,
The elastic part is
A main lip that extends substantially in the radial direction of the second raceway and contacts the peripheral surface of the second raceway surface;
When no pressure is applied from the outside in the axial direction, the stepped portion faces the stepped portion at an interval in the axial direction, and when pressure is applied from the outside in the axial direction, a secondary lip that contacts the stepped portion A bearing device comprising:

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