JP2013210083A - Rolling bearing with seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling bearing with seal configured to increase seal pressure against an inner race of a seal lip as a negative pressure increases when the negative load acts on the outside of a seal lip, and to reliably prevent leakage of grease in a bearing.SOLUTION: A rolling bearing with seal includes an annular lip support part 42 formed on an inner peripheral side of a seal member 34 to be thicker than a seal lip 43. The seal lip 43 protruded from the inner peripheral surface of the lip support part 42 has a trapezoidal cross section including: a cylindrical seal surface 43a in close contact with an outer peripheral surface of an inner ring 30; an outside surface 43c standing from an outer end of the seal surface 43a to reach the lip support part 42; and a conical inside surface 43b which inclines toward the outside surface 43c while extending radially outward from an inner end of the seal surface 43a, to reach the lip support part 42.

Description

  The present invention includes an inner ring, an outer ring surrounding the inner ring, a large number of rolling members arranged in an annular arrangement interposed between the inner and outer rings, and an inner ring arranged between the inner and outer rings so as to cover both sides of the group of rolling members. A pair of annular sealing members provided, and a mounting bead fixed to the outer ring on the outer periphery of each sealing member, and an outer peripheral surface of the inner ring rotating on the inner periphery of each sealing member. The present invention relates to an improvement in a rolling bearing with a seal in which seal lips that are slidably in contact with each other are formed.

  As disclosed in Patent Document 1, such a rolling bearing with a seal is interposed between a partition between two chambers having different internal pressures and a rotating shaft penetrating the partition. It is possible to prevent the pressure from moving between the two chambers while ensuring smooth rotation.

JP 2004-263734 A

  By the way, in the seal member of the rolling bearing with seal described in the above-mentioned Patent Document 1, the seal lip that is in close contact with the outer peripheral surface of the inner ring is pierced so as to go radially outward of the inner ring toward the outer side of the inner ring. Because of the conical shape, if a large negative pressure is generated in the chamber where the seal lip faces, the negative pressure acts on the frustoconical outer peripheral surface of the seal lip, causing the seal lip to move from the outer peripheral surface of the inner ring. Attempts to float and weaken the seal pressure on the inner ring of the seal lip, which may cause the grease inside the bearing to leak out.

  The present invention has been made in view of such circumstances, and when negative pressure acts on the outside of the seal lip, the higher the negative pressure, the higher the seal pressure with respect to the inner ring of the seal lip is increased. An object of the present invention is to provide a sealed bearing with a simple structure that can surely prevent leakage of grease.

  In order to achieve the above object, the present invention covers an inner ring, an outer ring surrounding the inner ring, a large number of rolling members in an annular arrangement interposed between the inner and outer rings, and both sides of these rolling member groups. And a pair of annular seal members disposed between the inner and outer rings, and a mounting bead fixed to the outer ring on the outer periphery of each seal member, and an inner periphery of each seal member , In the rolling bearing with seal formed on the outer peripheral surface of the inner ring so as to be rotatable and slidable, an annular lip support portion thicker than the seal lip is formed on the inner peripheral side of the seal member, The seal lip projecting from the inner peripheral surface of the lip support portion includes a cylindrical seal surface that is in close contact with the outer peripheral surface of the inner ring, an outer surface that reaches the lip support portion from the outer end of the seal surface, and the seal lip. From the inner edge of the surface. At least a portion to reach flop support portion, the first characterized by having an inclined inner surface such as by the said outer surface side while facing radially outward. In addition, the said rolling member respond | corresponds to the ball | bowl 32 in embodiment of this invention mentioned later.

  In addition to the first feature, the second feature of the present invention is that the axial width of the base of the seal lip is set larger than the radial height of the seal lip.

  Furthermore, in addition to the first or second feature, the present invention has a third feature in that an annular recess is formed on the outer surface of the lip support portion to directly above the seal lip.

  According to the first feature of the present invention, an annular lip support portion thicker than the seal lip is formed on the inner peripheral side of the seal member, and the seal lip protruding from the inner peripheral surface of the lip support portion is: A cylindrical sealing surface that is in close contact with the outer peripheral surface of the inner ring, an outer surface that reaches the lip support portion from the outer end of the seal surface, and at least a portion from the inner end of the seal surface to the lip support portion. , Because it has an inner surface inclined toward the outer surface while facing outward in the radial direction, even if an axial load due to a pressure difference between the inner and outer surfaces of the seal member is applied to the seal lip of the seal member, Since the seal lip has a large cylindrical seal surface that is in close contact with the outer peripheral surface of the inner ring, the seal lip exhibits great rigidity and does not tilt in the axial direction. In particular, when negative pressure acts on the outer surface of the seal lip, the load due to the pressure difference between the negative pressure and the atmospheric pressure inside the seal lip presses the inclined portion of the inner surface of the seal lip vertically. The radial component of the load presses the seal lip against the outer peripheral surface of the inner ring. As a result, the higher the negative pressure, the higher the sealing pressure on the inner ring of the sealing surface. Therefore, even if the seal lip is subjected to large positive and negative pressures on the outer surface, the seal lip can always maintain an appropriate close contact with the outer peripheral surface of the inner ring, and the grease inside the bearing can be surely discharged. Therefore, it is possible to provide a rolling bearing with a seal having a simple structure and high durability.

  According to the second feature of the present invention, by setting the axial width of the base of the seal lip to be larger than the radial height of the seal lip, the inclination rigidity of the seal lip in the axial direction is further enhanced. Tilt can be reliably prevented.

  According to the third aspect of the present invention, an annular recess that cuts into the outer surface of the lip support portion up to just above the seal lip is formed, so that the support rigidity of the lip support portion with respect to the seal lip is increased by the depth of the recess. Therefore, the friction torque between the seal lip and the inner ring can be adjusted, and the change in the allowable rotational torque of the inner ring can be dealt with.

1 is a cross-sectional view of an intake control device for an engine that includes a sealed rolling bearing according to a first embodiment of the present invention. FIG. 2 is an enlarged view of part 2 of FIG. 1. FIG. 3 is a view corresponding to FIG. 2 showing a second embodiment of the present invention.

  Embodiments of the present invention will be described below on the basis of preferred embodiments of the present invention shown in the accompanying drawings.

  In FIG. 1, a throttle body 1 constituting a part of an intake system of a vehicle engine such as a motorcycle or an automobile has an intake passage 2 connected to an intake port of the engine at the center thereof. A valve shaft 3 a of a butterfly throttle valve 3 that opens and closes the intake passage 2 is rotatably supported on the left and right side walls of the throttle body 1 via a pair of rolling bearings 4 and 5. At that time, the left rolling bearing 5 is particularly a rolling bearing with a seal, which will be described in detail later.

  A cap 6 that covers the right end of the throttle valve 3 and the rolling bearing 4 is fitted to the right side wall of the throttle body 1. The left end portion of the valve shaft 3a protrudes outward from the left side wall of the throttle body 1, and an electric motor 8 for driving the throttle valve 3 to open and close is connected to the protruding end portion via a reduction gear mechanism 9. The The reduction gear mechanism 9 includes a primary drive gear 11 fixed to the output shaft 10 of the electric motor 8, a primary driven gear 12 that is rotatably supported by the intermediate shaft 15 and meshes with the primary drive gear 11, and the primary drive gear 11. A secondary drive gear 13 integrally formed on one side of the driven gear 12 and a sector type secondary driven gear 14 fixed to the left end portion of the valve shaft 3a and meshing with the secondary drive gear 13 are provided. The rotation of the output shaft 10 of the motor 8 is decelerated in two steps and transmitted to the valve shaft 3a so that the throttle valve 3 can be opened and closed. The valve shaft 3a, the output shaft 10 and the intermediate shaft 15 The axes are arranged so as to be orthogonal to the axis of the intake passage 2 and to be parallel to each other.

  The secondary driven gear 14 is connected to a closing spring 17 that urges the secondary driven gear 14 in the closing direction of the throttle valve 3. A default lever 20 is rotatably supported on the valve shaft 3 a adjacent to the secondary driven gear 14. The default lever 20 is connected to an opening spring 22 that biases the default lever 20 in the opening direction of the throttle valve 3 and has a spring force larger than that of the closing spring 17. When the default lever 20 is rotated in the opening direction of the throttle valve 3 by the biasing force of the opening spring 22, the throttle valve 3 is driven in the opening direction via the secondary driven gear 14. A default stopper bolt (not shown) that receives 20 and stops the opening of the throttle valve 3 from the idle opening at a predetermined default opening is attached to the throttle body 1. Thus, when the electric motor 8 cannot be energized during the operation of the engine, the throttle valve 3 is held at the default opening by the biasing force of the opening spring 22. This makes it possible to supply the engine with an intake air amount that enables the vehicle to travel at a low speed to the maintenance shop.

  A control case 24 that accommodates the electric motor 8 and the reduction gear mechanism 9 and the like is integrally formed on the left side wall of the throttle body 1, and a synthetic resin that closes the opening on the left end surface of the control case 24. A case cover 25 made of metal is joined by bolts 26. The case cover 25 is provided with a throttle sensor 27 that detects the rotation angle of the valve shaft 3 a as the opening degree of the throttle valve 3. Further, the case cover 25 is provided with a ventilation hole (not shown) for ventilation inside the control case 24 in order to prevent dew condensation in the control case 24, so that the inside of the control case 24 is always at atmospheric pressure.

  Now, with reference to FIG. 2, the rolling bearing 5 with seal on the control case 24 side that supports the valve shaft 3a will be described.

  The rolling bearing 5 with seal includes an inner ring 30, an outer ring 31 surrounding the inner ring 30, a plurality of balls 32, 32... Interposed between the inner and outer rings 30, 31, and the balls 32, 32. A retainer 33 for holding the group and a pair of annular seal members 34, 34 disposed between the inner and outer rings 30, 31 so as to cover the group from both sides of the balls 32, 32,. Lubricating grease (not shown) is applied around 32.

  On the other hand, on the side wall 1a of the throttle body 1 on the control case 24 side, a shaft hole 35 through which the valve shaft 3a passes and a stepped portion 36 facing the control case 24 side are coaxially connected to the shaft hole 35. A bearing housing 37 is formed, and the stepped portion 36 is provided with an annular relief recess 38.

  The outer ring 31 of the rolling bearing 5 with seal is attached to the bearing housing 37 by press fitting, and the inner ring 30 is attached to the outer periphery of the valve shaft 3a by press fitting. At this time, the contact between the inner ring 30 and the side wall 1a is avoided by the escape recess 38.

  The annular seal member 34 is made of rubber or elastomer, and includes a plate-like wall 40, an annular mounting bead 41 bulging from the outer peripheral portion of the plate-like wall 40 toward the balls 32, 32,. An annular thick lip support 42 bulging from the inner periphery of the wall 40 toward the balls 32, 32, and the group side, and a seal lip 43 protruding from the inner peripheral surface of the lip support 42. A steel plate reinforcing ring 44 is embedded from the lip support 42 to the mounting bead 41.

  The mounting bead 41 is fitted and fixed in an annular mounting groove 39 provided on the inner peripheral surface of the outer ring 31.

  The seal lip 43 stands up in a direction perpendicular to the generatrix of the outer peripheral surface of the inner ring 30 from the outer end of the cylindrical seal surface 43a that is in close contact with the outer peripheral surface of the inner ring 30 with a certain allowance. An outer surface 43c that reaches the inner peripheral surface of the lip support portion 42, and an inner periphery of the lip support portion 42 that is inclined so as to approach the outer surface 43c while going radially outward from the inner end of the seal surface 43a. It is formed in an unequal leg trapezoidal cross section having a conical inner side surface 43b reaching the surface. At that time, the axial width W of the base portion of the seal lip 43, that is, the connecting portion with the lip support portion 42 is set to be greater than the radial height H of the seal lip 43. The fact that the outer surface 43c stands up in a direction perpendicular to the generatrix of the outer peripheral surface of the inner ring 30 can also mean that the outer surface 43c stands up in a direction perpendicular to the central axis X of the inner ring 30.

  The outer surface 43 c of the seal lip 43 is positioned so as to be flush with or near the outer surface 40 a of the plate-like wall 40, and the inner surface 43 b is positioned at the intermediate portion in the axial direction of the lip support portion 42. Accordingly, the seal lip 43 is offset from the center in the axial direction of the lip support portion 42 toward the outer side of the inner ring 30, and the inner peripheral end of the reinforcing ring 44 does not impair the elasticity of the seal lip 43. The seal lip 43 is offset inward of the seal member 34.

  Thus, the pair of left and right seal members 34, 34 disposed between the inner ring 30 and the outer ring 31 have a symmetrical structure, and when the rolling bearing 5 with seal is mounted on the bearing housing 37 and the valve shaft 3 a, There is no need to regulate the mounting direction.

  Next, the operation of the first embodiment will be described.

  During the operation of the engine, the throttle valve 3 is driven by the electric motor 8 via the reduction gear mechanism 9, and opens and closes the intake passage 2 to control the intake amount of the engine. At that time, since the valve shaft 3a of the throttle valve 3 is supported by a pair of left and right rolling bearings 4 and 5, the valve shaft 3a can be rotated, that is, the throttle valve 3 can be opened and closed smoothly. In addition, the rolling bearing 5 particularly on the control case 24 side includes a pair of seal members 34 and 34 covering both sides of the balls 32, 32..., So that the intake passage 2 and the control case 2 are formed by the seal members 34 and 34. It is possible to prevent the pressure from moving between the inside and the inside of the bearing 24 and to prevent the grease inside the rolling bearing 5 with a seal from flowing out.

  By the way, during the operation of the engine, positive pressure and negative pressure are alternately generated in the intake passage 2 due to the intake pulsation, and the pulsation pressure passes through the shaft hole 35 and the relief recess 38 and then the rolling bearing 5 with seal. Acts on the outer surface of the seal member 34 on the intake passage 2 side. Here, since the inside of the control case 24 is always at atmospheric pressure, the pulsating pressure (positive pressure and negative pressure), the atmospheric pressure, and the pressure are applied to the seal member 34 on the intake passage 2 side in the sealed rolling bearing 5. An outward axial load and an inward axial load due to the differential pressure of the seal member 34 are alternately applied to try to incline the most flexible seal lip 43 in the seal member 34 in the axial direction. Since the lip 43 has a cylindrical wide sealing surface 43a that is in close contact with the outer peripheral surface of the inner ring 30, it exhibits great rigidity and does not tilt in the axial direction. In addition, since the base axial width W of the seal lip 43 is set to be larger than the radial height H, the inclination rigidity (bending rigidity) of the seal lip 43 in the axial direction is further strengthened, and the inclination is surely ensured. Can be prevented.

  In particular, when a negative pressure is applied to the outer surface 43 c of the seal lip 43, the load F due to the differential pressure between the negative pressure and the atmospheric pressure in the control case 24 causes a conical inner surface 43 b of the seal lip 43 to be formed. Is pushed vertically, the radial component force F1 of the load F presses the seal lip 43 against the outer peripheral surface of the inner ring 30. As a result, the higher the negative pressure, the higher the sealing pressure on the inner ring 30 of the seal surface 43a. The axial component force F2 of the load F is the outward axial load that tends to tilt the seal lip 43 outward.

  As described above, the seal lip 43 can always maintain an appropriate close contact state of the seal surface 43a with the outer peripheral surface of the inner ring 30 even when the pulsation pressure of the intake passage 2 is received. It is possible to obtain the rolling bearing 5 with a seal that can be surely prevented and has a simple structure and high durability.

  Next, a second embodiment of the present invention shown in FIG. 3 will be described.

  In the second embodiment, an annular recess 45 is formed on the outer surface of the lip support portion 42 of the seal member 34 so as to bite up to just above the seal lip 43. Since other configurations are the same as those of the previous embodiment, portions corresponding to those of the previous embodiment in FIG. 3 are denoted by the same reference numerals, and redundant description is omitted.

  According to the second embodiment, the support rigidity of the lip support portion 42 with respect to the seal lip 43 can be moderated by the depth of the recess 45, thereby adjusting the friction torque between the seal lip 43 and the inner ring 30. When the specification of the throttle body 1 or the like is changed, it is possible to cope with a change in the allowable rotational torque of the valve shaft 3a, that is, the allowable rotational torque of the inner ring 30 press-fitted to the valve shaft 3a.

  The present invention is not limited to the above embodiment, and various design changes can be made without departing from the scope of the invention. For example, the outer surface 43c of the seal lip 43 can be formed in a conical shape symmetrical to the inner surface 43b. Moreover, the rolling bearing 5 with a seal according to the present invention can be used for supporting a rotating shaft penetrating a partition wall between two chambers having different internal pressures in various devices other than an engine intake control device. The present invention can also be applied to a roller bearing using a rolling member as a roller.

5. Rolling bearing 30 with seal 30 ... Inner ring 31 ... Outer ring 32 ... Rolling member (ball)
34 ... Seal member 41 ... Mounting bead 42 ... Lip support part 43 ... Seal lip 43a ... Seal surface 43b ... Inner surface 43c ... Outer surface 45 ... Concave

Claims (3)

An inner ring (30), an outer ring (31) surrounding the inner ring (30), a large number of rolling members (32) arranged in an annular arrangement between the inner and outer rings (30, 31), and a group of these rolling members (32) A pair of annular seal members (34) disposed between the inner and outer rings (30, 31) so as to cover both sides of the outer ring (30, 31). 31) a mounting bead (41) fixed to the inner ring, and a seal lip (43) which is in close contact with the outer peripheral surface of the inner ring so as to be rotatable and slidable is formed on the inner periphery of each seal member (34). In a rolling bearing,
An annular lip support portion (42) that is thicker than the seal lip (43) is formed on the inner peripheral side of the seal member (34), and the seal lip projects from the inner peripheral surface of the lip support portion (42). (43) is a cylindrical sealing surface (43a) that is in close contact with the outer peripheral surface of the inner ring (30), and an outer surface (43c) that reaches the lip support portion (42) from the outer end of the sealing surface (43a). , The inner surface of the sealing surface (43a) is inclined so that at least a part from the inner end of the sealing surface (43a) to the lip support portion (42) is inclined radially outward and toward the outer surface (43c). (43b) and a rolling bearing with a seal. The rolling bearing with seal according to claim 1,
A rolling bearing with seal, wherein the axial width (W) of the base of the seal lip (43) is set larger than the radial height (H) of the seal lip (43). The rolling bearing with seal according to claim 1 or 2,
A rolling bearing with a seal, wherein an annular recess (45) is formed on the outer surface of the lip support portion (42) so as to bite directly above the seal lip (43).

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