JP2013050114A - Seal device and wheel supporting rolling bearing unit with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a structure capable of preventing changes of fastening margins of respective seal lips 42 to 44 constituting a seal device 14c, even if the moment is applied to a hub 2.SOLUTION: A seal ring 32 having the seal lips 42 to 44 freely supports a relative rotation with respect to the hub 2 by using a rolling bearing 33 with respect to the hub 2. Furthermore, a fixing core bar 52 is internally fittingly fixed at the inner peripheral surface of an outer ring 1, and the fixing core bar 52 and the seal ring 32 are connected to each other by a bellows seal 53 which is non-linear in cross section in such a manner that relative displacement to the axial direction and the radial direction is enabled, and the relative displacement to the circumferential direction is disenabled. By such a constitution, when the hub 2 is inclined with respect to the outer ring 1, the seal ring 32 can be inclined together with the hub 2. Accordingly, the fastening margins of the respective seal lips 42 to 44 can be prevented from being changed.

Description

  The present invention relates to, for example, a seal device for closing an opening end of a rolling bearing incorporated in a rotation support portion of various mechanical devices such as a wheel support rolling bearing unit for supporting a vehicle (automobile) wheel on a suspension device, and the like. Further, the present invention relates to an improvement of a rolling bearing unit for supporting a wheel with a seal device provided with the seal device. Specifically, based on the moment load, etc., a structure that prevents the seal lip tightening margin from changing even when the center axis of the rotating raceway and the center axis of the stationary raceway are inclined to each other is realized. Invented as much as possible.

  Rolling bearings such as ball bearings, cylindrical roller bearings, and tapered roller bearings are incorporated in the rotation support portions of various mechanical devices. Such a rolling bearing incorporates a sealing device to prevent the grease enclosed in the inner space of the rolling bearing from leaking to the outside, and various foreign matters such as rainwater, mud, and dust existing outside the rolling bearing. To prevent it from getting inside. FIG. 4 shows a structure for rotatably supporting a driving wheel of a vehicle on a suspension device as an example of a wheel bearing rolling bearing unit with a sealing device provided with such a sealing device.

  The wheel support rolling bearing unit with a seal device includes an outer ring 1 corresponding to a stationary side bearing ring, a hub 2 also corresponding to a rotating side bearing ring, and a plurality of rolling elements 3, 3. It consists of. Of these, the hub 2 is formed by combining a hub body 4 and an inner ring 5. Each of the rolling elements 3, 3 includes a double row outer ring raceway 6, 6 formed on the inner peripheral surface of the outer ring 1 and a double row inner ring raceway 7, 7 formed on the outer peripheral surface of the hub 2. A plurality of them are provided so as to roll freely. Then, in order to rotatably support the wheel with respect to the suspension device, the outer ring 1 is fixed to a knuckle 8 constituting the suspension device, and the wheel is coupled and fixed to a mounting flange 9 provided on the hub body 4. Further, since the structure shown in FIG. 4 is a structure for supporting the drive wheel, the spline shaft 12 attached to the constant velocity joint 11 is engaged with the spline hole 10 provided in the central portion of the hub body 4. ing.

  Among the rolling bearing units for supporting a wheel with a sealing device as described above, the interior in which the rolling elements 3 and 3 are installed, which are present between the inner peripheral surface of the outer ring 1 and the outer peripheral surface of the hub 2. Grease is sealed in the space 13 to lubricate the rolling contact portions of the rolling surfaces of the rolling elements 3 and 3 and the outer ring raceways 6 and 6 and the inner ring raceways 7 and 7. Sealing devices 14a and 14b are provided between the inner peripheral surface of both ends in the axial direction of the outer ring 1, the outer peripheral surface of the inner end portion in the axial direction of the inner ring 5 and the outer periphery of the intermediate portion in the axial direction of the hub body 4, respectively. Thus, both end portions in the axial direction of the internal space 13 are closed. In the present specification, “inner with respect to the axial direction” means a side that is closer to the middle in the width direction of the vehicle when assembled to the vehicle, and the right side of each figure. On the other hand, on the left side of each figure, the side that is outward in the width direction of the vehicle is referred to as outside in the axial direction.

  Of the sealing devices 14a and 14b, the sealing device 14a for closing the opening on the inner end side in the axial direction of the internal space 13 is configured as shown in FIG. The seal device 14 a is called a combination seal ring, and includes a seal ring 15 and a slinger 16. The seal ring 15 includes a metal core 17 and a seal material 18, and the metal core 17 includes an outer diameter side cylindrical part 19 that can be fitted and fixed to the inner peripheral surface of the inner end of the outer ring 1 in the axial direction. The outer diameter side cylindrical portion 19 includes an outer diameter side annular portion 20 that is bent inward in the diameter direction from the outer edge in the axial direction. The sealing material 18 is made of an elastic material such as an elastomer such as rubber and includes three sealing lips 21 to 23 on the outer side, the middle side, and the inner side, and the base end portion is coupled to the cored bar 17. It is fixed.

  The slinger 16 is bent radially outwardly from the inner diameter side cylindrical portion 24 that can be externally fitted and fixed to the outer peripheral surface of the inner ring 5 in the axial direction, and from the inner edge of the inner diameter side cylindrical portion 24 in the axial direction. In addition, the entire inner ring portion 25 is L-shaped in cross section and has an annular shape. Of the three seal lips 21 to 23 constituting the seal ring 15, the end of the outer seal lip 21, called a side lip, is provided on the outermost diameter side so as to protrude inward in the axial direction. The edge is slidably contacted with the outer circumferential surface of the inner diameter side annular portion 25 constituting the slinger 16 over the entire circumference. In contrast, the leading edges of the remaining two intermediate and inner seal lips 22 and 23 are in sliding contact with the outer peripheral surface of the inner diameter side cylindrical portion 24 constituting the slinger 16 over the entire circumference.

  On the other hand, the sealing device 14b that closes the opening on the outer end side in the axial direction of the internal space 13 is constituted by a single seal ring 26 having no slinger as shown in FIG. The seal ring 26 includes a core metal 27 and a seal material 28. Of these, the sealing material 28 is made of an elastic material such as an elastomer such as rubber, and includes three sealing lips 29 to 31 on the outer side, the middle side, and the inner side. Bonded and fixed. Then, the distal end edge of the outer seal lip 29, which is called a side lip and protrudes outward in the axial direction, is brought into sliding contact with the inner surface of the base end portion of the mounting flange 9 over the entire circumference, and the remaining two The intermediate edge of the inner and inner seal lips 30, 31 is slid over the entire circumference from a continuous portion of the inner surface of the base end portion and the outer peripheral surface of the hub body 4 in the axial direction to the outer peripheral surface of the axial direction intermediate portion. Touching.

  As described above, in the case of the wheel support rolling bearing unit with the seal device, the internal space 13 is formed by closing the axial end openings of the internal space 13 with the seal devices 14a and 14b as described above. In addition to preventing foreign matter such as muddy water from entering the interior, the grease enclosed in the internal space 13 is prevented from leaking to the outside. Therefore, in order to improve the sealing performance of the sealing devices 14a and 14b, the sliding contact between the tip edges of the sealing lips 21 to 23 and 29 to 31 constituting the sealing devices 14a and 14b and the mating surface is possible. It is necessary that the state is appropriate.

  However, in the case of the wheel bearing rolling bearing unit provided with the sealing devices 14a and 14b as described above, for example, as described in Patent Document 1, a wheel is configured with respect to the hub 2 when the vehicle turns. A moment load is applied through the mounting flange 9 from the ground contact surface of the tire. As a result, the constituent members are elastically deformed, and the sliding contact state between the leading edge of each of the seal lips 21 to 23 and 29 to 31 (particularly the outer seal lips 21 and 29) and the mating surface is uneven in the circumferential direction. Thus, problems such as a decrease in durability and a decrease in sealing performance of the seal lips 21 to 23 and 29 to 31 occur. With regard to this point, focusing on the outer seal lip 21 where the change in the tightening margin tends to be large among the seal lips 21 to 23, taking the seal device 14a on the axially inner end opening side of the internal space 13 as an example. 7 to 8 will be described.

  As shown by an arrow in FIG. 7, a description will be given of a case where a moment M associated with turning travel is applied to the hub 2 in the clockwise direction of FIG. 7. In this case, the outer ring 1 and the hub 2 are inclined due to the elastic deformation of each part, but at the contact portion between the rolling elements 3, 3 and the outer ring raceways 6, 6 and the inner ring raceways 7, 7. Therefore, the inclination (inclination angle) of the hub 2 is larger than that of the outer ring 1. Here, assuming that the outer ring 1 is not inclined (the outer ring 1 is fixed in a neutral state), the central axis of the hub 2 extends from the α position representing the center line of the outer ring 1 to the β position. It is relatively inclined by the angle θ (relative inclination occurs in the hub 2). As a result, the slinger 16 that is externally fitted and fixed to the inner end of the inner ring 5 that constitutes the hub 2 is also relative to the seal ring 15 supported by the outer ring 1 by the angle θ. Tilt. In the state shown in FIG. 7, in the upper part of FIG. 7, the inner diameter side annular portion 25 constituting the slinger 16 is displaced in the direction away from the core metal 17 as shown in FIG. . As a result, the tightening margin of the outer seal lip 21 is reduced in the upper portion. On the other hand, in the lower portion of FIG. 7, the inner diameter side annular ring portion 25 is displaced in a direction approaching the cored bar 17 as shown in FIG. As a result, the allowance for tightening the outer seal lip 21 increases in the lower portion. On the other hand, the sealing device 14b that closes the axially outer end opening of the internal space 13 moves in the opposite direction to the sealing device 14a on the inner end side. In any case, in the portions of the sealing devices 14a and 14b where the tightening allowance of the outer seal lips 21 and 29 is reduced, the foreign matter intrusion preventing action by the outer seal lips 21 and 29 is impaired.

  For this reason, conventionally, based on the moment M, even if the outer ring and the hub are relatively inclined and the seal lip tightening margin is partially reduced, these seals can be secured so that the sealability of the part can be secured. The lip tightening margin was set. Specifically, the tightening allowance of each seal lip in the neutral state is set to be large, and even if the relative inclination between the outer ring and the hub occurs, the allowance for each seal lip is set to the entire circumference. As a result, it was left as much as possible to ensure sealing performance. However, when the tightening margin is set to be large in this way, as a compensation, the sliding resistance with respect to each seal lip is increased, and each of these seal lips is easily worn or set. An increase in sliding resistance is not preferable because it leads to an increase in rotational resistance of the hub and a deterioration in driving performance centering on fuel efficiency and acceleration performance. In addition, it is not preferable that the roller bearing is easily worn or worn because it leads to a decrease in durability of the rolling bearing.

  In recent years, the rolling bearing unit for supporting a wheel with a seal device as described above is applied to a large vehicle. However, such a wheel-supporting rolling bearing unit with a seal device for a large vehicle is more likely to cause the problem of change in the tightening margin of the seal lip as described above. That is, the relative inclination angle generated between the outer ring and the hub based on the moment load affects the controllability, stability, etc. of the vehicle, so it is almost the same for large vehicles and small vehicles (or medium vehicles). However, since the rolling bearing unit for supporting a wheel for a large vehicle has a larger outer diameter than that for a small vehicle or a medium-sized vehicle, the outer diameter of the sealing device to be incorporated is also increased. In particular, in the case of a rolling bearing unit for supporting wheels for driving wheels as shown in FIG. 4, the outer diameter dimension is further increased due to the necessity of inserting a spline shaft inside, and the outer diameter dimension of the sealing device to be incorporated is also increased. Become bigger. When the outer diameter of the seal device is increased in this way, the amount of displacement of the seal lip when the relative inclination occurs between the outer ring and the hub increases, so that the change in the tightening allowance of the seal lip also increases. As a result, problems such as a decrease in the durability of the seal lip and a decrease in the sealing performance are likely to occur.

  As described above, in the case of a rolling bearing unit for supporting a wheel for a large vehicle, the change in the tightening margin of the seal lip becomes large (the tightening margin tends to be insufficient), which will be described in more detail. . For example, in the case of a sealing device having three seal lips as shown in FIG. 5, the center of the three inclined seal lips (the central axis of the hub is inclined with respect to the central axis of the outer ring). In the case of a side lip (outer seal lip) that has a large distance from the inclination center), in other words, a change in tightening margin is likely to be large, generally, from the base end of the side lip to the tip edge The axial dimension (width dimension) of this is about 2/3 of the axial dimension (width dimension) of the entire sealing device, and the size of the tightening margin is about 1/3 of the axial dimension of the side lip. . For this reason, the size of the tightening margin is about 2/9 of the axial dimension of the entire sealing device. On the other hand, the amount of displacement (amplitude) that the seal lip (side lip) can follow varies depending on the material of the seal lip, that is, the hardness. In general rolling bearing units for supporting wheels, acrylonitrile butadiene rubber (NBR) having a hardness of about 70 (durometer A) is often used as the material of the seal lip. In this case, the seal lip follows. The possible amount of displacement is about 1/3 of the fastening allowance (see Non-Patent Document 1). Accordingly, the tightening allowance change (amplitude) that the side lip can follow is about 2/27 of the axial dimension of the entire sealing device. On the other hand, if the tightening margin is set in proportion to the outer diameter (diameter) of the sealing device, the seal torque increases in proportion to the square of the diameter, so the seal incorporated in the wheel bearing rolling bearing unit for large vehicles. Even in the case of a device (in the case of a large-diameter sealing device), the tightening allowance cannot be increased easily. For this reason, the larger the diameter of the sealing device incorporated in the wheel bearing rolling bearing unit for a large vehicle, the more likely the fastening margin is insufficient.

  In addition, there exist invention described in patent document 2, 3 as a prior art document relevant to this invention. In these Patent Documents 2 and 3, a constricted portion with a reduced thickness is provided at the base end portion of the outer seal lip so that the change in the tightening allowance of the outer seal lip is less likely to be connected to the pressure change in the sliding contact portion. The structure is described. According to such a structure, the contact pressure between the leading edge of the outer seal lip and the mating surface against changes in the tightening margin of the outer seal lip due to the relative inclination between the outer ring and the hub that occurs during turning. Changes are insensitive. However, even in the case of the structures described in Patent Documents 2 and 3, since the size of the tightening allowance in the neutral state is set to be large, the sliding resistance and wear of the outer seal lip are reduced by the tightening allowance. Compared to the case where the size is not increased, an increase is unavoidable.

JP 2003-240003 A Japanese Utility Model Publication No. 5-73364 Japanese Utility Model Publication No. 5-73365

Co-authored by Toshige Chikamori and Yoshio Kawahara, “Tribology Series 7 Sealing Device”, Koshobo Co., Ltd., published on December 1, 1975, first edition, page 150

  In the present invention, in view of the circumstances as described above, even when the central axis of the rotating raceway and the central axis of the stationary raceway are inclined to each other based on the moment load or the like, the tightening margin of the seal lip changes. The invention was invented to realize a structure capable of preventing this.

The sealing device of the present invention is used to close an end opening of a space existing between a rotating side peripheral surface and a stationary side peripheral surface facing each other, and includes a seal ring, a rolling bearing, and a seal And a detent mechanism with a function.
Of these, the seal ring includes a cored bar and an elastic sealing material reinforced by the cored bar. Further, the seal material is provided with one or more seal lips that are in sliding contact with the rotation side raceway or a member (for example, a slinger) that rotates together with the rotation side raceway.
The rolling bearing has an outer ring equivalent member, an inner ring equivalent member, and a plurality of rolling elements, and is provided at a portion between the rotating side race ring and the seal ring. And this seal ring is supported so that relative rotation with respect to this rotation side raceway ring is possible.
The detent mechanism with a sealing function seals a portion between the stationary peripheral surface and the seal ring, and the central axis of the rotating side raceway and the central axis of the stationary side raceway are inclined with respect to each other. This prevents the seal ring from rotating relative to the stationary ring (rotating around the center axis of the seal ring) while allowing relative displacement between the seal ring and the stationary ring. To do.

In the case of carrying out the present invention, preferably, as in the invention described in claim 2, for example, the detent mechanism with a sealing function is constituted by a fixing member and a flexible seal.
Of these, the fixing member is fitted and fixed to the stationary peripheral surface.
In addition, the flexible seal has a substantially annular shape as a whole, and a cross-sectional shape with respect to a virtual plane including the center line is non-linear (for example, a square shape, a bellows shape, a sawtooth shape, etc.) Are bonded and fixed to the fixing member and the core metal constituting the seal ring, respectively.

Alternatively, as in the invention described in claim 3, the detent mechanism with a sealing function is constituted by a convex surface portion formed on a part of the core metal and an O-ring.
Among these, the convex surface portion is formed in a portion of the core bar that faces the stationary peripheral surface, and the cross-sectional shape with respect to the virtual plane including the center line is an arc shape.
The O-ring has a circular cross section and is disposed in a groove formed on the stationary peripheral surface, and is elastically sandwiched between the bottom of the groove and the convex surface over the entire circumference. (Compressed).
Preferably, when the invention described in claim 3 is carried out, preferably, the outer surface shape (outer peripheral surface shape or inner peripheral surface shape) of the convex surface portion is set such that the center axis of the rotating side raceway and the stationary side raceway are A partial spherical convex surface with the center of inclination when the central axis is inclined to each other as its center is defined.

  Further, when the present invention is carried out, preferably, as in the invention described in claim 4, for example, a seal device incorporated in a wheel bearing rolling bearing unit for rotatably supporting a wheel on a suspension device is claimed. It is set as the sealing apparatus of the invention described in any one of 1-3.

According to the sealing device of the present invention configured as described above and the rolling bearing unit for supporting a wheel with the sealing device, the central axis of the rotating side raceway and the central axis of the stationary side raceway are inclined with respect to each other based on moment load or the like. Even in this case, it is possible to effectively prevent the seal lip fastening margin from changing.
That is, in the case of the sealing device of the present invention, the seal ring, which is prevented from rotating relative to the stationary side race ring by the detent mechanism with a sealing function, can be rotated relative to the rotation side race ring by the rolling bearing. It is supported. Further, the anti-rotation mechanism with a seal function is configured so that the center ring of the rotation side raceway and the center axis of the stationary side raceway are inclined with respect to each other due to a moment load, for example. Not only can the relative displacement with the side raceway be allowed, but also when such relative displacement occurs, the portion between the seal ring and the stationary side raceway can be sealed. Therefore, the seal ring constituting the seal device of the present invention does not rotate with the rotating side raceway (still with the stationary side raceway), but when a moment load or the like is applied, the stationary ring The stationary bearing ring is tilted together with the rotating bearing ring while maintaining a sealing property with the bearing ring. As a result, according to the sealing device of the present invention, even when the center axis of the rotating side raceway and the center axis of the stationary side raceway are inclined with respect to each other due to a moment load or the like, the seal lip is tightened. It is possible to effectively prevent changes in bills.
As a result, according to the sealing device of the present invention, it is not necessary to set a large margin for the sealing lip in the neutral state in order to ensure sealing performance. The durability of the lip can be improved. For example, when applied to a wheel support rolling bearing unit with a seal device, the durability of the wheel support rolling bearing unit with a seal device can be improved, and at the same time, the running performance of a vehicle centering on fuel efficiency and acceleration performance. Can be improved.
In particular, the present invention provides a seal lip (for a seal device) at a level (for example, 1G, preferably 0.8G) at which the turning acceleration during turning of the vehicle does not occur during normal driving or rarely occurs. When applied to a wheel bearing rolling bearing unit for a large vehicle, the change (amplitude) of the side lip) exceeds 2/27 of the axial dimension of the entire sealing device. An advantageous effect is obtained.

The enlarged view equivalent to the X section of FIG. 4 which shows the 1st example of embodiment of this invention. The enlarged view equivalent to the Y section of Drawing 4 showing the 2nd example similarly. The enlarged view equivalent to the X section of Drawing 4 showing the 3rd example similarly. Sectional drawing of the rolling bearing unit for wheel support with a sealing apparatus which shows the 1st example of a conventional structure. The partial expanded sectional view of the sealing device assembled | attached to the X section of FIG. The partial expanded sectional view of the sealing device similarly assembled | attached to the Y part. Sectional drawing of the rolling bearing unit for wheel support with a sealing device which shows the state which a hub inclines with the moment load added at the time of driving | running | working of a vehicle. The partial expanded sectional view which shows the displacement state of the slinger of the sealing device assembled | attached to the rolling bearing unit for wheel support with a sealing device shown in FIG.

[First example of embodiment]
FIG. 1 shows a first example of an embodiment of the present invention corresponding to claims 1, 2 and 4. The seal device 14c of this example is configured by combining a seal ring 32, a rolling bearing 33, a detent mechanism 34 with a sealing function, and a slinger 35 to form a combined seal ring. The sealing device 14c is mounted between an outer ring 1 that is a stationary side race ring that rotates relative to each other and a hub 2 (inner ring 5) that is a rotary side race ring. The axially inner end opening of the internal space 13 existing between the outer peripheral surface of the hub 2 is blocked. The structure, operation, and effects of the other parts other than the sealing device 14c including the sealing device 14b that closes the axially outer end opening of the internal space 13 are the same as those of the conventional structure described above.

  The seal ring 32 includes a core metal 36 and a seal material 37. The core metal 36 includes a substantially cylindrical stationary-side cylindrical portion 38 provided on the radially outer portion, and an outer portion bent from the axially outer end of the stationary-side cylindrical portion 38 toward the radially inner side. A diameter-side annular ring portion 39, a folded tube portion 40 that is bent from the inner diameter-side end portion of the outer-diameter-side annular portion 39 toward the axially outward direction, and an intermediate portion thereof is folded axially inward by 180 degrees; And an inner diameter side circular ring portion 41 that is bent inwardly in the diameter direction from the axially inner end portion of the folded tube portion 40. The sealing material 37 is reinforced by the cored bar 36 having such a configuration. The sealing material 37 is made of an elastic material such as an elastomer such as rubber, and includes a plurality of (three in the illustrated example) sealing lips 42 to 44. In the case of carrying out this example, the outer diameter side annular portion 39 is omitted, and the stationary side cylindrical portion 38 and the outer diameter side portion of the folded tube portion 40 are directly connected (with the same diameter). You can also.

  The slinger 35 is formed by bending a metal plate into a substantially L-shaped cross section, and is a rotation-side cylindrical portion 45 that is externally fitted and fixed to the outer peripheral surface in the axial direction inner end portion of the inner ring 5 constituting the hub 2. And a rotation-side circular ring portion 46 that is bent from the axially inner end of the rotation-side cylindrical portion 45 toward the outside in the diameter direction. In the case of this example, the leading edge of each of the seal lips 42 to 44 is brought into sliding contact with such a slinger 35. Specifically, of these seal lips 42 to 44, the tip edge of the outer seal lip 42, called a side lip, is slidably contacted with the outer circumferential surface of the rotation-side annular portion 46 over the entire circumference. Yes. On the other hand, the end edges of the intermediate seal lip 43 and the inner seal lip 44, called radial lips, are in sliding contact with the outer peripheral surface of the rotation-side cylindrical portion 45 over the entire circumference. In particular, in the case of this example, the size of the fastening allowance of each of the seal lips 42 to 44 in the neutral state is not set to be large in consideration of the inclination of the hub 2 when a moment load is applied. {Set to normal size (sliding resistance and neutral wear in neutral state)}.

  The rolling bearing 33 includes a rolling bearing outer ring 47, a rolling bearing inner ring 48, and a plurality of balls (rolling elements) 49. In the illustrated example, the rolling bearing 33 has a high rigidity against a moment load. It is a point contact type radial ball bearing. A deep groove type outer ring raceway 50 is formed on the inner peripheral surface of the rolling bearing outer ring 47, and a deep groove type inner ring raceway 51 is formed on the outer peripheral surface of the rolling bearing inner ring 48. . The cross-sectional shapes of both the tracks 50 and 51 are so-called gothic arch shapes in which a pair of arcs having a radius of curvature larger than the radius of curvature of the rolling surface of each ball 49 intersect at the center in the width direction. Yes. Thereby, the rolling surfaces of the balls 49 and the tracks 50 and 51 are in contact with each other at two points (four points in total). In the case of this example, the rolling bearing 33 having such a configuration is provided between the slinger 35 that is externally fitted and fixed to the inner ring 5 and the core metal 36 that constitutes the seal ring 32. Specifically, the rolling bearing inner ring 48 constituting the rolling bearing 33 is externally fitted and fixed to the outer peripheral surface of the outer half portion in the axial direction of the rotating cylindrical portion 45 constituting the slinger 35, and the outer ring for rolling bearing is provided. 47 is fitted and fixed to the inner peripheral surface of the folded tube portion 40 constituting the cored bar 36. In the case of this example, by providing such a rolling bearing 33, the seal ring 32 is supported so as to be relatively rotatable with respect to the hub 2 (inner ring 5) and impossible to relatively displace in the axial direction. Yes.

  The anti-rotation mechanism 34 with a sealing function includes a substantially cylindrical fixing core metal 52 corresponding to the fixing member described in the claims, and a bellows seal having an overall ring shape that is also equivalent to a flexible seal. (Diaphragm) 53. Among these, the fixing core metal 52 is fitted and fixed to the inner peripheral surface of the inner end portion in the axial direction of the outer ring 1. The bellows seal 53 is made of an elastic material such as an elastomer such as rubber (same material in this example), like the seal material 37 constituting the seal ring 32. The circumferential force applied to the bellows seal 53 includes the friction torque generated by the seal lips 42 to 44, the elasticity of the bellows seal 53 and the seal lips 42 to 44, and the seal. Since only the rolling resistance (dynamic torque) generated in the rolling bearing 33 that supports the own weight of the ring 32, the amount of elastic deformation (expansion / contraction amount) in the circumferential direction of the bellows seal 53 is small enough to be ignored (substantially). It does not expand or contract in the circumferential direction). The outer peripheral edge portion of the bellows seal 53 is vulcanized and bonded to the inner peripheral surface of the axially inner end portion of the fixing metal core 52 over the entire periphery. Similarly, the inner peripheral edge portion is the core of the seal ring 32. Of the gold 36, vulcanized and bonded to the outer peripheral surface of the axially inner end portion of the stationary-side cylindrical portion 38 disposed radially inward of the fixing core metal 52. In the case of this example, the outer peripheral side of the bellows seal 53 covers the outer peripheral surface and the inner end surface of the axial inner end of the fixing core metal 52 and functions as a nose gasket. The inner peripheral edge portion is made to continue to the sealing material 54, and the outer peripheral edge portion of the sealing material 37 constituting the seal ring 32 (the portion covering the inner end surface in the axial direction of the stationary side cylindrical portion 38). Thereby, both the said sealing materials 37 and 54 and the said bellows seal 53 are comprised integrally.

  The bellows seal 53 has a non-linear cross-sectional shape with respect to a virtual plane including the center line. In the example shown in the drawing, this bellows seal 53 is bent (flexible) by making this cross-sectional shape into a substantially cross-sectional shape with a radially intermediate portion protruding inward in the axial direction. Accordingly, the fixing core metal 52 and the seal ring 32 connected via such a bellows seal 53 can be relatively displaced in the radial direction and the axial direction by the amount of bending of the bellows seal 53. However, both peripheral portions of the bellows seal 53 are bonded to the fixing core metal 52 and the seal ring 32 over the entire circumference, and the bellows seal 53 cannot expand and contract in the circumferential direction. The relative displacement in the circumferential direction between the cored bar 52 and the seal ring 32 is prevented. The cross-sectional shape of the bellows seal 53 is not limited to that shown in the drawings, and may be any shape having a bend, such as a bellows shape or a sawtooth shape.

  The anti-rotation mechanism 34 with the sealing function having such a configuration seals (seals) a portion between the inner peripheral surface of the outer ring 1 and the seal ring 32 (stationary side cylindrical portion 38), and through the portion, In addition to preventing foreign matter such as muddy water from entering the internal space 13, the grease enclosed in the internal space 13 is prevented from leaking to the outside. Further, the detent mechanism 34 with the sealing function utilizes the bending of the bellows seal 53 to cause the seal ring 32 (stationary side) when the center axis of the hub 2 is inclined with respect to the center axis of the outer ring 1. The inclination of the cylindrical portion 38) relative to the outer ring 1 (relative displacement in the direction of arrow A in FIG. 1) is allowed. However, the seal ring 32 is prevented from rotating around the central axis of the seal ring 32 with respect to the outer ring 1.

In the case of this example having the above-described configuration, a moment load is applied to the hub 2 from the ground contact surface of the tire constituting the wheel via the mounting flange 9 (see FIGS. 4 and 7) when the vehicle turns. Even when the central axis of the hub 2 is inclined with respect to the central axis of the outer ring 1 (relative inclination occurs between the outer ring 1 and the hub 2), the tightening allowance of the seal lips 42 to 44 is changed. Can be prevented.
That is, in the case of the sealing device 14c of the present example, the seal ring 32, which is prevented from rotating relative to the outer ring 1 by the anti-rotation mechanism 34 with the sealing function, is connected to the hub 2 (slinger) by the rolling bearing 33. 35) is supported so as to be relatively rotatable. Further, the detent mechanism 34 with the sealing function is configured so that a moment load is applied to the hub 2 when the vehicle turns, and the center ring of the hub 2 is inclined with respect to the center axis of the outer ring 1. The inclination of 32 (stationary side cylindrical portion 38) with respect to the outer ring 1 can be allowed. Moreover, even when tilted in this way, the sealing performance (sealing performance) between the seal ring 32 (stationary side cylindrical portion 38) and the outer ring 1 can be secured.

For this reason, the seal ring 32 does not rotate with the hub 2 (slinger 35) (still with the outer ring 1), but when a moment load is applied to the hub 2, the seal ring 32 and the outer ring 1 With the hub 2 (slinger 35) inclined, the sealability of the intermediate portion is ensured. In particular, in the case of this example, the seal ring 32 is supported by the hub 2 (slinger 35) using a four-point contact type rolling bearing 33. 2 (slinger 35) is substantially equal to the inclination angle. As a result, in the case of this example, even when a moment load is applied to the hub 2 and the central axis of the hub 2 is inclined with respect to the central axis of the outer ring 1, the sealing lips 42 to 44 are tightened. It is possible to effectively prevent changes in bills. Thereby, in the case of this example, in order to ensure sealing performance, it is not necessary to set a large margin for tightening the seal lips 42 to 44 in the neutral state. The friction (torque) can be reduced and the durability of each of the seal lips 42 to 44 can be improved (sag prevention). And while improving the durability of the wheel bearing rolling bearing unit with the seal device, it is possible to improve the running performance of the vehicle centering on fuel efficiency and acceleration performance.
Other configurations and operations / effects are the same as those of the conventional structure described above.

[Second Example of Embodiment]
FIG. 2 shows a second example of the embodiment of the present invention, which also corresponds to the first, second and fourth aspects. The sealing device 14d of the present example closes the axially outer end opening of the internal space 13 existing between the inner peripheral surface of the outer ring 1 and the outer peripheral surface of the hub 2. As the sealing device 14c for closing the axially inner end opening of the internal space 13, the one shown in the first example of the above-described embodiment is used. The sealing device 14d of this example has a structure in which the slinger 35 (see FIG. 1) is omitted from the sealing device 14c of the first example.

That is, in the case of this example, the inner ring 48 for the rolling bearing constituting the rolling bearing 33 is directly fitted and fixed to the outer circumferential surface of the intermediate portion in the axial direction of the hub body 4. Of the seal lips 42 to 44 constituting the seal ring 32, the distal end edge of the outer seal lip 42 is brought into sliding contact with the entire inner surface of the base end portion of the mounting flange 9, and the intermediate and inner seal lips 43 are also brought into contact. , 44 is in sliding contact with the entire periphery of the continuous portion of the inner surface of the base end portion and the outer peripheral surface of the hub body 4 in the axial direction or the outer peripheral surface of the intermediate portion in the axial direction. In the case of this example having such a configuration, a change in the tightening allowance of each of the seal lips 42 to 44 can be effectively prevented even with respect to the seal device 14d that closes the axially outer end opening of the internal space 13.
The configuration of the other parts is basically the same as that of the sealing device 14c of the first example except that the inside and outside in the axial direction are reversed, and the same operation and effect are obtained. Are denoted by the same reference numerals and description thereof is omitted.

[Third example of embodiment]
FIG. 3 shows a third example of an embodiment of the present invention corresponding to claims 1, 3 and 4. Similarly to the case of the first example of the above-described embodiment, the sealing device 14e of this example is also an axial direction of the internal space 13 existing between the inner peripheral surface of the outer ring 1 and the outer peripheral surface of the hub 2. The inner end opening is closed. The sealing device 14e of the present example and the sealing device 14c of the first example are substantially the same in the other parts except for the configuration of the detent mechanism 34a with a sealing function. To do.

In the case of this example, the radial dimension of the outer diameter side annular portion 39a constituting the core metal 36a of the seal ring 32a is increased (extended radially outward), and the outer diameter side annular portion 39a The shape of the stationary side cylindrical portion 38a formed in a state of being bent inward in the axial direction from the radial side end portion is different from that of the first example. Specifically, the stationary-side cylindrical portion 38a is formed into a partial spherical shape, and the outer peripheral surface shape of the stationary-side cylindrical portion 38a facing (closely facing) the inner peripheral surface of the outer ring 1 The center of inclination when tilting with respect to the central axis of the outer ring 1 {the point γ (see FIG. 7) located at the axial center of both rows of rolling elements 3, 3 on the central axis of the outer ring 1 and the hub 2} as its center, a curvature radius is a partially spherical convex surface 55 is R _55. Therefore, the cross-sectional shape when the outer peripheral surface of the stationary-side cylindrical portion 38a is cut by a virtual plane including the central axis of the cored bar 36a is an arc shape. Further, in the case of this example, even when the hub 2 is inclined with respect to the outer ring 1 with the point γ as the center, the partial spherical convex surface 55 and an O-ring 57 which will be described later are formed from this point γ. The distance to the contact portion is constant.

Further, a concave groove 56 having a rectangular cross section is formed in a portion of the inner peripheral surface of the outer ring 1 facing the partial spherical convex surface 55, and an O-shaped cross section made of an elastic material is formed in the concave groove 56. The outer diameter side half of the ring 57 is accommodated with almost no gap. The O-ring 57 is elastically sandwiched (compressed) over the entire circumference between the bottom of the groove 56 and the partial spherical convex surface 55. In such a state, the O-ring 57 rotates around the cross-sectional center O ₅₇ (rotation about the center of the cross-sectional shape when cut along a virtual plane including the central axis of the O-ring 57, as shown in FIG. Only rotation in the direction of arrow B is possible {rotation in the circumferential direction (rotation around the central axis of the O-ring 57) is disabled}. In particular, in the case of the present example, since the distance from the point γ to the contact portion between the O-ring 57 and the partial spherical convex surface 55 is constant, the O-ring 57 can be used even when the seal ring 32a is inclined. No further compressive stress is applied to the surface.

In the case of this example, in order to easily rotate the O-ring 57 around the cross-sectional center O ₅₇ (by the frictional force acting between the partial spherical convex surface 55), Grease is held (particularly in the concave groove 56). For this purpose, an outer-diameter side seal lip (nose gasket) 58 is provided at a portion between the outer circumferential surface of the axially inner end portion of the stationary side cylindrical portion 38a and the inner circumferential surface of the outer ring 1 in the axial direction. The grease in the vicinity of the O-ring 57 is prevented from leaking inward in the axial direction. Further, foreign matter such as muddy water is prevented from entering the portion where the O-ring 57 is installed. In the case of this example, the outer diameter side seal lip 58 is formed by a part of the seal material 37 constituting the seal ring 32a.

In the case of this example having the above-described configuration, the portion between the outer ring 1 and the seal ring 32a (stationary side cylindrical portion 38a) is sealed by the O-ring 57 and the outer diameter side seal lip 58, Through this portion, it is possible to prevent foreign matters such as muddy water from entering the internal space 13 and to prevent the grease enclosed in the internal space 13 from leaking to the outside. Further, the anti-rotation mechanism 34a with a sealing function causes the O 2 due to the frictional force that acts on the contact portion with the partial spherical convex surface 55 when the central axis of the hub 2 is inclined with respect to the central axis of the outer ring 1. By rotating the ring 57 around the cross-sectional center O ₅₇ , the seal ring 32 a is allowed to tilt with respect to the outer ring 1. However, the relative rotation of the seal ring 32 a with respect to the outer ring 1 is prevented by the frictional resistance acting between the O-ring 57 and the inner surfaces of the partial spherical convex surface 55 and the concave groove 56.

Also in the case of this example having the above-described configuration, when the vehicle turns, a moment load is applied to the hub 2 from the ground contact surface of the tire constituting the wheel via the mounting flange 9 (see FIG. 4). Even when the center axis of the hub 2 is inclined with respect to the center axis of the outer ring 1, it is possible to prevent the tightening allowance of the seal lips 42 to 44 from changing. Further, in the case of this example, since it is not necessary to use the bellows seal 53 (see FIG. 1), it is advantageous in reducing the radial dimension of the sealing device 14e as compared with the case of the first example. Become.
Other configurations and operations / effects are the same as in the case of the first example.

  In each example of the embodiment described above, the case where a four-point contact type rolling bearing is used as the rolling bearing constituting the seal device has been described. However, the rolling bearing constituting the seal device of the present invention is described below. The invention is not limited to such a four-point contact type (multi-point contact type) rolling bearing. When a slight change is allowed with respect to the tightening margin of the seal lip (a slight difference is allowed between the inclination angle of the seal ring and the inclination angle of the rotating side raceway), the radius of curvature with respect to the cross-sectional shape of each raceway surface It is also possible to use a single row deep groove ball bearing with a reduced ball diameter ratio. Various rolling bearings such as an angular ball bearing, a radial needle bearing, and a cylindrical roller bearing can also be used. Also, a plurality of rolling bearings and sliding bearings can be used in combination. Further, for the outer ring equivalent member and the inner ring equivalent member constituting the rolling bearing, the outer ring for the rolling bearing and the inner ring for the rolling bearing can be provided separately from the core metal and the slinger, as in the case of the respective examples. However, a metal core or slinger (or an inner ring constituting a hub, a hub body) directly forming each track may be substituted. In this case, it is preferable to harden a member such as a core metal or a slinger by carburizing or nitriding. As described above, when a member such as a core bar or slinger is used as a substitute, it is possible to reduce the cost associated with the reduction in the number of parts, reduce the weight of the sealing device, and shorten the radial dimension.

  Further, when the present invention is carried out, the number of seal lips constituting the seal device may be one (preferably only the side lips that are liable to change the tightening allowance), or two or as in the case of the above examples. Three or more may be used. In each example of the above-described embodiment, the outer ring is a stationary side race ring and the hub (inner ring) is a rotation side race ring (inner ring rotation type wheel support rolling bearing unit). The present invention can also be applied to a structure (outer ring rotation type wheel support bearing unit) in which the outer ring is a rotation side race and the inner ring is a stationary side race.

DESCRIPTION OF SYMBOLS 1 Outer ring 2 Hub 3 Rolling element 4 Hub body 5 Inner ring 6 Outer ring raceway 7 Inner ring raceway 8 Knuckle 9 Mounting flange 10 Spline hole 11 Constant velocity joint 12 Spline shaft 13 Internal space 14a-14e Sealing device 15 Seal ring 16 Slinger 17 Core metal 18 Seal material 19 Outer diameter side cylindrical portion 20 Outer diameter side annular portion 21 Outer seal lip 22 Intermediate seal lip 23 Inner seal lip 24 Inner diameter side cylindrical portion 25 Inner diameter side annular portion 26 Seal ring 27 Core metal 28 Seal material 29 Outer seal Lip 30 Intermediate seal lip 31 Inner seal lip 32, 32a Seal ring 33 Rolling bearings 34, 34a Non-rotating mechanism with seal function 35 Slinger 36, 36a Core metal 37 Sealing material 38, 38a Cylindrical part 39, 39a Outside diameter side circle Ring portion 40 Folded tube portion 41 Inner diameter side annular portion 42 Side seal lip 43 Intermediate seal lip 44 Inner seal lip 45 Rotating side cylindrical portion 46 Rotating side annular portion 47 Rolling bearing outer ring 48 Rolling bearing inner ring 49 Ball 50 Outer ring raceway 51 Inner ring raceway 52 Stationary side tubular portion 53 Bellows seal 54 Seal material 55 Partial spherical convex surface 56 Concave groove 57 O-ring 58 Outer diameter side seal lip

Claims (4)

It is used to seal the end opening of the space that exists between the rotating side circumferential surface formed on the rotating side races facing each other and the stationary side circumferential surface formed on the stationary side races. A ring, a rolling bearing, and a detent mechanism with a sealing function;
Of these, the seal ring is composed of a cored bar and an elastic sealant reinforced by the cored bar, and this sealant is a member that rotates together with the rotating side raceway or the rotating side raceway. On the other hand, there is a seal lip that slidably contacts the entire circumference.
The rolling bearing is provided in a portion between the rotation-side raceway and the seal ring, and supports the seal ring so as to be rotatable relative to the rotation-side raceway,
The detent mechanism with a sealing function seals a portion between the stationary side peripheral surface and the seal ring, and the central axis of the rotating side raceway and the central axis of the stationary side raceway are inclined with respect to each other. The seal ring is allowed to rotate relative to the stationary side raceway while allowing relative displacement between the seal ring and the stationary side raceway.
Sealing device.   An anti-rotation mechanism with a sealing function includes a fixing member fitted and fixed to the stationary peripheral surface, and an overall shape of a substantially annular shape, and both peripheral portions in the radial direction thereof are formed of the fixing member and a core metal constituting the seal ring. The sealing device according to claim 1, further comprising: a flexible seal bonded to each other and having a non-linear cross-sectional shape with respect to a virtual plane including a center line.   A detent mechanism with a sealing function is formed in a portion facing the stationary side peripheral surface of the core metal constituting the seal ring, and a convex surface portion whose cross-sectional shape with respect to a virtual plane including the center line is an arc shape, It is arrange | positioned in the ditch | groove formed in this stationary-side surrounding surface, and is equipped with the O-ring elastically pinched over the perimeter between the bottom part of this ditch | groove, and this convex surface part. Sealing device.   Rotation side raceway having a rotation side raceway on the rotation side circumferential surface, stationary side raceway ring having a stationary side raceway on the stationary side circumferential surface, and provided between these rotation side raceway and stationary side raceway so as to be capable of rolling. A rolling bearing unit for supporting a wheel with a seal device, comprising: a plurality of rolling elements; and a seal device that closes an end opening of a space existing between the rotating side peripheral surface and the stationary side peripheral surface. A wheel bearing rolling bearing unit with a seal device, wherein the seal device is the seal device according to any one of claims 1 to 3.

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