JP6776833B2 - Rolling bearing equipment - Google Patents

Description

The present invention relates to an improvement of a rolling bearing device used by being incorporated in a rotation support portion of various mechanical devices.

A rolling bearing unit for supporting wheels is used as a rolling bearing device for rotatably supporting the wheels of an automobile with respect to a suspension device. As an example of such a rolling bearing unit for wheel support, Patent Document 1 describes one having a seal structure as shown in FIG.

The wheel support rolling bearing unit has an outer ring 1 that does not rotate even when used while being supported and fixed to a suspension device, a hub 2 that rotates together with the wheel when used while the wheel is supported and fixed, and an inner circumference of the outer ring 1. A plurality of rolling elements 3 provided so as to be rollable between the outer ring track 4 provided on the surface and the inner ring track 5 provided on the outer peripheral surface of the hub 2 are provided.

Further, the axial outer end opening of the internal space 6 provided with each rolling element 3 existing between the inner peripheral surface of the outer ring 1 and the outer peripheral surface of the hub 2 is closed by the seal ring 7. .. As a result, the lubricating grease sealed in the internal space 6 is prevented from leaking to the external space, and foreign matter such as rainwater is prevented from entering the internal space 6 from the external space.

In the whole of this specification, "outside" in the axial direction means the outside in the width direction of the vehicle body in the assembled state of the automobile, the left side of each figure, and conversely the center side in the width direction of the vehicle body. The right side of each figure is referred to as "inside" in the axial direction.

The seal ring 7 has an annular core metal 8 internally fitted and fixed to the axially outer end portion of the outer ring 1, and a sealing material 9 coupled and fixed to the entire circumference of the core metal 8. Of these, the sealing material 9 has three sealing lips 10 to 12 arranged in the order of the first sealing lip 10, the second sealing lip 11, and the third sealing lip 12 from the side closer to the internal space 6. Then, the tips of the first to third seal lips 10 to 12 are slidably contacted with the seal sliding contact surface 13 provided on the surface of the hub 2 over the entire circumference.

Further, the first seal lip 10 is inclined in a direction toward the internal space 6 side from the outer diameter side edge which is the base end edge toward the inner diameter side end edge which is the tip edge. As a result, the grease leakage prevention function of the first seal lip 10 is enhanced. Further, the second seal lip 11 and the third seal lip 12 are inclined in the direction toward the external space side (away from the internal space 6) from the base end edge to the tip end edge, respectively. As a result, the foreign matter intrusion prevention function of the second seal lip 11 and the third seal lip 12 is enhanced.

Japanese Unexamined Patent Publication No. 2012-180922

In the case of the rolling bearing unit for wheel support as described above, when the hub 2 rotates, the rolling contact portion between the outer ring track 4 and the inner ring track 5 and each rolling element 3 and the first to third seal lips 10 to 12 are sealed. Friction heat is generated at the sliding contact portion (sliding contact portion) with the sliding contact surface 13. As a result, the bearing temperature rises, and the internal space 6, the space 14 between the first lips sandwiched between the first and second seal lips 10, 11 and the second and third seal lips 11, The pressure between the second lip spaces 15 sandwiched between the 12 lips tends to increase.

Here, the second seal lip 11 and the third seal lip 12 are inclined in the direction toward the external space side from the base end edge toward the tip end edge, respectively. Therefore, the air in the spaces 14 and 15 between the first and second lips easily leaks to the external space side through the sliding contact portion between the second and third seal lips 11 and 12 and the seal sliding contact surface 13. It has become. Therefore, even when the pressure in the spaces 14 and 15 between the first and second lips tends to increase, the air in the spaces 14 and 15 between the first and second lips is the second and third seal lips. By leaking to the external space side through the sliding contact portion between 11 and 12 and the sealing sliding contact surface 13, it is easy to suppress an increase in pressure in the spaces 14 and 15 between the first and second lips.

On the other hand, the first seal lip 10 is inclined in the direction toward the internal space 6 side from the base end edge toward the tip end edge. Therefore, the air in the internal space 6 is less likely to leak to the external space side through the sliding contact portion between the first seal lip 10 and the seal sliding contact surface 13. Therefore, when the pressure in the internal space 6 tends to increase, it is difficult to suppress the increase in the pressure.

Therefore, when the pressure in the internal space 6 tends to increase, the first seal lip 10 is elastically deformed so as to be pressed (attached) to the seal sliding contact surface 13 due to this pressure. (1) There is a problem that the frictional force acting on the sliding contact portion between the seal lip 10 and the sealing sliding contact surface 13 tends to increase.

Further, when the frictional force acting on the sliding contact portion between the first seal lip 10 and the seal sliding contact surface 13 increases as described above, it is generated at the sliding contact portion between the first seal lip 10 and the seal sliding contact surface 13. Friction heat increases. Then, the temperature of the space 14 between the first lips, which is easily affected by the frictional heat, tends to rise further. Then, when the rotation of the hub 2 is stopped from this state and the bearing temperature is lowered, the air in the first lip space 14 contracts, and a strong negative pressure tends to be generated in the first lip space 14. Then, due to this strong negative pressure, the first and second seal lips 10 and 11 are elastically deformed so as to stick to the seal friction contact surface 13, and the first and second seal lips 10 and 11 and the seal slide are attached. There is a problem that the frictional force acting on the sliding contact portion with the contact surface 13 tends to increase.

In view of the above circumstances, the present invention realizes a structure in which the frictional force acting on the sliding contact portion between the first seal lip and the sealing sliding contact surface can be suppressed from increasing with a change in bearing temperature. It was invented to be.

The rolling bearing device of the present invention includes an outer diameter side raceway ring, an inner diameter side raceway ring, a plurality of rolling elements, an internal space, a seal ring, and a space between the first lips .
Of these, the outer diameter side raceway ring has an outer ring raceway on the inner peripheral surface and does not rotate even during use.
Further, the inner diameter side raceway ring rotates at the time of use.
Further, the plurality of rolling elements are rotatably provided between the outer ring track and the inner ring track.
Further, the internal space exists between the inner peripheral surface of the outer diameter side raceway ring and the outer peripheral surface of the inner diameter side raceway ring , and the plurality of rolling elements are provided .
Further, the seal ring closes the axial end opening of the internal space.
Further, the seal ring has an annular core metal fixed to the axial end portion of the outer diameter side raceway ring, and a sealing material fixed to the entire circumference of the core metal.
Further, the sealing material is arranged at a position in contact with the internal space and extends (inclined) in the direction toward the internal space side from the base end portion toward the tip end portion, and the first sealing lip. It has a second seal lip arranged at a position adjacent to the internal space on the opposite side. Then, sliding the respective tip portions of the first seal lip and a second sheet Rurippu, the seal sliding surface provided on the inner diameter side raceway ring or the surface of the other member fixed to the inner diameter side raceway ring I'm letting you.
Further, the space between the first lips is sandwiched between the sealing material and the sealing sliding contact surface, between the first sealing lip and the second sealing lip, and by the first sealing lip. It is partitioned from the internal space.
In particular, when the rolling bearing device of the present invention, the sealing material has a coupling portion for coupling the proximal end of the second sheet Rurippu the base end portion of the first seal lip, and the coupling portion A constricted portion is provided in a portion adjacent to the radial outer side of the bearing and located in the radial inner side of the core metal.
Also, the state is equal with the pressure of the pressure between the first lip between space of the inner space, wherein one of the seal sliding surface of said first seal lip tip of the the sliding contact portion second sheet Rurippu A thinning portion is provided in a state of being recessed in the radial direction at one or a plurality of locations in the circumferential direction located in the vicinity of the first seal lip, which is a portion between the tip portion and the portion in sliding contact .

When the present invention is carried out, for example, the seal sliding contact surface is provided on the surface of the inner diameter side raceway ring , and at least a part of the seal sliding contact surface is inside the inside in the axial direction. The inclined surface portion is inclined in a direction in which the outer diameter dimension becomes larger toward the opposite side of the space, and the structure in which the thinning portion is provided on the inclined surface portion can be adopted.

In the case of carrying out the present invention, for example, the seal sliding contact surface is provided on the surface of a sliding contact ring which is another member fixed to the inner diameter side raceway ring, and the thinning portion is the said. It is possible to adopt a configuration provided so as to penetrate the sliding contact ring (for example, in the radial direction).

According to the rolling bearing device of the present invention having the above-described configuration, it is possible to prevent the frictional force acting on the sliding contact portion between the first seal lip and the sealing sliding contact surface from increasing with a change in the bearing temperature. Be done.

FIG. 3 is a cross-sectional view of a rolling bearing unit for wheel support showing a simplified seal structure according to a first example of an embodiment of the present invention. Similarly, an enlarged view of part A in FIG. 1 showing a concrete seal structure. Similarly, an enlarged view of part B in FIG. Similarly, the views (a), (b), and (c) of the thinned portion viewed from the radial outside of the hub. The same figure as FIG. 2 regarding the 2nd example of the Embodiment of this invention. Similarly, a view of the thinned portion viewed from the radial outside of the hub. The same figure as FIG. 2 regarding the 3rd example of the Embodiment of this invention. FIG. 5 is an enlarged view corresponding to part C of FIG. 1 showing a concrete seal structure according to a fourth example of the embodiment of the present invention. FIG. 3 is a partial cross-sectional view showing an example of a conventional structure of a rolling bearing unit for wheel support.

[First Example of Embodiment]
The first example of the embodiment of the present invention will be described with reference to FIGS. 1 to 4.
The rolling bearing unit for wheel support of this example is for driving wheels, and includes an outer ring 16, a hub 17, a plurality of rolling elements 18, 18, and seal rings 19, 20.

The outer ring 16 corresponds to the outer diameter side raceway ring described in the claims, and has a stationary side flange 21 on the outer peripheral surface and double-row outer ring raceways 22a and 22b on the inner peripheral surface, respectively. .. At the time of use, such an outer ring 16 does not rotate while being supported by the suspension device by coupling and fixing the stationary side flange 21 to the knuckle of the suspension device.

The hub 17 corresponds to the inner ring side raceway ring described in the claims, and is configured by connecting the hub main body 23 and the inner ring 24, and is coaxial with the outer ring 16 on the inner diameter side of the outer ring 16. Concentric).

Of the outer peripheral surface of the hub main body 23, the portion of the outer ring 16 protruding outward in the axial direction from the axial outer end opening is a circular ring-shaped rotating side for supporting and fixing the wheel (driving wheel) and the rotating member for braking. A flange 25 is provided. Further, on the outer peripheral surface of the hub body 23, a portion facing the outer ring track 22a of the axial outer row provided on the inner peripheral surface of the outer ring 16 is provided with the inner ring track 26a of the axial outer row. Further, among the outer peripheral surfaces of the hub main body 23, a small diameter step portion 27 is provided at an axial inner end portion facing the outer ring track 22b of the axial inner row provided on the inner peripheral surface of the outer ring 16. Further, a spline hole 28 for engaging the spline shaft, which is a drive shaft, is provided at the radial center of the hub body 23.

An inner ring track 26b in the inner row in the axial direction is provided on the outer peripheral surface of the inner ring 24. Such an inner ring 24 is fixed to the small diameter step portion 27 of the hub main body 23 by tightening and fitting, and the inner end surface in the axial direction is suppressed by the caulking portion 29 formed at the inner end portion in the axial direction of the hub main body 23. It is attached.

A plurality of rolling elements 18 and 18 are held in a portion between the outer ring track 22a and the inner ring track 26a in the outer row in the axial direction and a portion between the outer ring track 22b and the inner ring track 26b in the inner row in the axial direction. It is provided so as to be rollable while being held by the vessels 30a and 30b. In the illustrated example, balls are used as the rolling elements 18 and 18, but in the case of a rolling bearing unit for supporting wheels of an automobile, which is heavy, a tapered roller may be used instead of the balls.

Of the seal rings 19 and 20, the seal ring 19 on the outer side in the axial direction is an inside provided with a plurality of rolling elements 18 and 18 existing between the inner peripheral surface of the outer ring 16 and the outer peripheral surface of the hub 17. The axial outer end opening of the space 31 is closed, and the axial inner seal ring 20 closes the axial inner end opening of the internal space 31. As a result, the lubricating grease sealed in the internal space 31 is prevented from leaking to the external space, and foreign matter such as rainwater is prevented from entering the internal space 31 from the external space.

One of the seal rings 19 is composed of a core metal 32 and a seal material 33.

Of these, the core metal 32 is formed in an annular shape as a whole by punching and bending a metal plate such as a steel plate, and has a cylindrical fitting cylinder portion 34 and a fitting cylinder portion. The outward flange portion 35 bent outward in the radial direction from the outer end portion in the axial direction of 34, and the fitting cylinder portion 34 is folded back in the outward direction in the axial direction and inward in the radial direction from the inner end portion in the axial direction. It has an inner diameter support portion 36 that is bent. Then, the fitting cylinder portion 34 is internally fitted to the axial outer end portion of the outer ring 16 by tightening, and the axial inner side surface of the outer flange portion 35 is brought into contact with the axial outer end surface of the outer ring 16. I'm letting you. As a result, the core metal 32 is supported and fixed to the outer end portion in the axial direction of the outer ring 16 in a state where the core metal 32 is positioned in the axial direction.

The sealing material 33 is made of an elastic material such as an elastomer such as rubber, and is bonded and fixed to the entire circumference of the core metal 32. Such a sealing material 33 has three seal lips 37 to 39, a constricted portion 40, an outer diameter side covering portion 41, and an auxiliary lip 42.

The three seal lips 37 to 39 are arranged in the order of the first seal lip 37, the second seal lip 38, and the third seal lip 39 from the side closer to the internal space 31, and the tip of each is a hub main body. The seal sliding contact surface 43 provided on the surface of the 23 is slidably contacted over the entire circumference. More specifically, the seal sliding contact surface 43 includes a circular ring surface portion 44 provided at the radial inner end portion of the axial inner surface of the rotating side flange 25 and whose axial position does not change with respect to the radial direction. A curved portion (corner R portion) having a concave arc shape as a generatrix, which is provided adjacent to the radial inner side of the annular surface portion 44 and is curvedly inclined in the axial direction inward toward the radial inward side. It is composed of 45 and a cylindrical surface portion 46 provided adjacent to the inside of the curved surface portion 45 in the axial direction and whose outer diameter dimension does not change with respect to the axial direction. A chamfered portion 47 is provided between the cylindrical surface portion 46 and the inner ring track 26a in the outer row in the axial direction. In the case of this example, the tip of the first seal lip 37 is on the cylindrical surface 46, the tip of the second seal lip 38 is on the curved surface 45, and the tip of the third seal lip 39 is on the annular surface 44. Are all in contact with each other all around. Further, in this state, between the seal material 33 and the seal sliding contact surface 43, the space 48 between the first lip and the second, which are sandwiched between the first and second seal lips 37, 38. A second lip space 49 sandwiched between the third seal lips 38 and 39 is formed.

Further, the first seal lip 37 is extended (inclined) in the direction toward the internal space 31 side from the outer diameter side edge which is the base end edge toward the inner diameter side end edge which is the tip edge. As a result, the grease leakage prevention function of the first seal lip 37 is enhanced. Further, the second seal lip 38 and the third seal lip 39 are extended (inclined) in the direction toward the external space side (away from the internal space 31) from the base end edge to the tip end edge, respectively. As a result, the foreign matter intrusion prevention function of the second seal lip 38 and the third seal lip 39 is enhanced.

Further, among the first to third seal lips 37 to 39, the base end portion of the first seal lip 37 arranged at a position in contact with the internal space 31 and the first seal lip 37 opposite to the internal space 31. The base ends of the second seal lips 38 arranged adjacent to each other on the side are connected to each other, and the joints 50 between the base ends of the first and second seal lips 37 and 38 are connected to each other. It is arranged radially inside the gold 32.

The constricted portion 40 is adjacent to the radial outer side of the joint portion 50 between the base end portions of the first and second seal lips 37 and 38 and has a diameter larger than that of the core metal 32 (inner diameter side end portion of the inner diameter support portion 36). It is provided in a portion located inside in the direction. The constricted portion 40 is formed so that the wall thickness of the radial middle portion is smaller (constricted) than the wall thickness of both radial end portions, with both side surfaces in the axial direction having an arcuate cross-sectional shape recessed in the axial direction. ing. Further, the radial outer end portion of the constricted portion 40 is close to the inner diameter side end portion of the core metal 32 (inner diameter support portion 36). Then, in the case of this example, based on the fact that the first and second seal lips 37 and 38 swing around the constricted portion 40 as the swing center, these first and second seal lips 37, The 38 can move slightly in the axial direction. In particular, in the case of this example, the radial outer end of the constricted portion 40 is close to the inner diameter side end of the core metal 32, in other words, the radial outer end of the constricted portion 40 is made of metal. It is supported by a highly rigid core metal 32. Therefore, the first and second seal lips 37 and 38 can swing stably with the constricted portion 40 as the swing center.

The outer diameter side covering portion 41 is provided so as to cover the axial outer surface and the radial outer end edge surface of the outward flange portion 35 constituting the core metal 32, and is provided from the outer peripheral surface of the axial outer end portion of the outer ring 16. Also protrudes outward in the radial direction.

The auxiliary lip 42 is provided all around the outer diameter side covering portion 41 in a state of protruding outward in the axial direction from a portion near the outer end of the outer surface in the axial direction. Further, the auxiliary lip 42 is inclined in the radial direction outward as it goes outward in the axial direction. Then, the tip of the auxiliary lip 42 is curved in the direction toward the inward in the axial direction as it goes inward in the radial direction, which is provided at the portion near the inner end in the axial direction on the inner side surface in the axial direction of the rotary side flange 25. The step portion 51 is closely opposed to the step portion 51 via a minute gap. As a result, a labyrinth seal is formed between the tip portion of the auxiliary lip 42 and the step portion 51.

Further, in the case of this example, the diameters of the seal sliding contact surfaces 43 are located at a plurality of locations in the circumferential direction located in the vicinity of the first seal lip 37 between the first and second seal lips 37 and 38, respectively. The recesses 52 and 52 having an arcuate cross section are provided so as to be recessed inward in the direction. More specifically, in the seal sliding contact surface 43 (cylindrical surface portion 46), the pressure P _{1 in} the internal space 31 and the pressure P _{2 in the} space 48 between the first lips are equal to each other (P ₁ = P ₂ ). A circle of a portion (adjacent portion or a portion separated by a small axial distance) adjacent to the axially outer side (opposite to the internal space 31) with respect to the portion where the tip of the first seal lip 37 is in sliding contact. Recesses 52 and 52 having an arcuate cross section are provided at a plurality of locations at equal intervals in the circumferential direction so as to be recessed inward in the radial direction, respectively. In the case of this example, each of these recesses 52 and 52 corresponds to the thinning portion described in the claims. In the case of this example, the shapes of the recesses 52 and 52 viewed from the outside in the radial direction are circular as shown in FIG. 4A. However, when the present invention is carried out, the shapes of the recesses 52 and 52 viewed from the outside in the radial direction are an elliptical shape extending in the circumferential direction as shown in FIG. 4 (b) and an oval shape as shown in FIG. 4 (c). ), Various shapes such as an oval shape extending in the axial direction and a polygonal shape can be adopted.

Although detailed illustration is omitted in this example, of the seal rings 19 and 20, the seal ring 20 inward in the axial direction may be used alone or in combination with a sliding contact ring (slinger) to form a seal ring. , Is assembled to the axial inner end opening of the internal space 31.

In the case of the rolling bearing unit for wheel support of this example configured as described above, when the hub 17 rotates, the rolling contact portions between the outer ring raceways 22a and 22b and the inner ring raceways 26a and 26b and the rolling elements 18 and 18 and the first Friction heat is generated at the sliding contact portion (sliding contact portion) between the first to third seal lips 37 to 39 and the seal sliding contact surface 43. As a result, the bearing temperature rises, and the pressures of the internal space 31, the first lip space 48, and the second lip space 49 tend to rise.

Here, the second seal lip 38 and the third seal lip 39 are inclined in the direction toward the external space side from the base end edge toward the tip end edge, respectively. Therefore, the air in the spaces 48 and 49 between the first and second lips easily leaks to the external space side through the sliding contact portion between the second and third seal lips 38 and 39 and the seal sliding contact surface 43. It has become. Therefore, even when the pressure in the spaces 48 and 49 between the first and second lips tends to increase, the air in the spaces 48 and 49 between the first and second lips is the second and third seal lips. By leaking to the external space side through the sliding contact portion between 38 and 39 and the sealing sliding contact surface 43, it is easy to suppress an increase in pressure in the spaces 48 and 49 between the first and second lips.

On the other hand, the first seal lip 37 is inclined in the direction toward the internal space 31 side from the base end edge toward the tip end edge. That is, the posture of the first seal lip 37 is such that the air in the space 48 between the first lips easily leaks to the internal space 31 side through the sliding contact portion between the first seal lip 37 and the seal sliding contact surface 43. On the other hand, the air in the internal space 31 does not easily leak to the space 48 side (external space side) between the first lips through the sliding contact portion between the first seal lip 37 and the seal sliding contact surface 43.

However, in the case of this example, as the pressure in the internal space 31 increases, the pressure P ₁ in the internal space 31 tends to be higher than the pressure P _{2 in the} space 48 between the first lips (P ₁ > P ₂ ). In the case of, based on the fact that the first and second seal lips 37 and 38 swing around the constricted portion 40 as the swing center, these first and second seal lips 37 and 38 are axially outside. Move slightly towards. At the same time, the first seal lip 37 is pushed by the pressure P ₁ of the internal space 31 and is curved. As a result, when the pressure P ₁ in the internal space 31 becomes larger than the pressure P _{2 in the} space 48 between the first lips by a predetermined amount or more, the tip of the first seal lip 37 is placed in the seal sliding contact surface 43. Ride on the axial range in which each recess 52 is provided {see (a) and (b) of FIG. 3}.

As a result, for example, as shown in FIG. 3B, the portion of the tip of the first seal lip 37 that hangs on the recess 52 is elastic in such a manner that the tip edge is slightly lifted from the seal sliding contact surface 43. Deform. Then, the air in the internal space 31 easily leaks (moves) into the space 48 between the first lips through the portion where such elastic deformation occurs (the portion of the tip of the first seal lip 37 that hangs on the recess 52). (Easy). Alternatively, although not shown, the internal space 31 and the space between the first lips 48 communicate with each other through the recess 52 at the portion of the tip of the first seal lip 37 that hangs on the recess 52. Then, the air in the internal space 31 is more likely to leak into the space 48 between the first lips through the portion that communicates in this way.

Therefore, in the case of this example, even when the pressure P ₁ of the internal space 31 tends to be higher than the pressure P _{2 of} the first lip space 48 (P ₁ > P ₂ ), as described above. The pressure between the internal space 31 and the first lip space 48 is caused by the air in the internal space 31 leaking to the side of the first lip space 48 through the portion of the tip of the first seal lip 37 that hangs on the recess 52. The difference can be reduced or eliminated. As a result, it is possible to suppress an increase in the frictional force acting on the sliding contact portion between the first seal lip 37 and the sealing sliding contact surface 43.

Further, in the case of this example, after that, the rotation of the hub 17 is stopped and the bearing temperature is lowered, so that the air in the first lip space 48 contracts and the pressure P in the first lip space 48. _{Even when 2} tends to be lower than the pressure P ₁ of the internal space 31 (P ₁ > P ₂ ), the first seal lip 37 has the same action as when the pressure of the internal space 31 rises described above. The tip portion hangs on the recess 52, and the air in the internal space 31 leaks to the first lip space 48 side through the portion hung on the recess 52, so that the pressure between the internal space 31 and the first lip space 48 is increased. The difference can be reduced or eliminated. As a result, it is possible to suppress an increase in the frictional force acting on the sliding contact portion between the first seal lip 37 and the sealing sliding contact surface 43.

When the present invention is carried out, when the pressure P ₁ of the internal space 31 becomes larger than the pressure P _{2 of} the first lip space 48 by a predetermined amount or more, the recess 52 of the tip of the first seal lip 37 The depth (diameter) of the recess 52 is provided if the effect that the air in the internal space 31 easily leaks to the space 48 side between the first lips can be obtained through the portion (the gap formed in this portion). The direction width dimension) is not particularly limited. In the case of this example, under such conditions, the depth of the recess 52 is set to a size equal to or less than the wall thickness of the tip of the first seal lip 37.

Further, in the case of this example, the continuous portion (opening edge portion of the recess 52) between the inner surface of the recess 52 and the seal sliding contact surface 43 is a smooth surface (chamfered portion), so that the tip of the first seal lip 37 is formed. It is possible to prevent the portion of the portion that hangs on the recess 52 from being damaged.

Further, in the case of this example, when the pressure in the internal space 31 rises, the tip portion of the second seal lip 38 swings and displaces slightly outward in the axial direction and outward in the radial direction with the constricted portion 40 as the swing center. The tip of the second seal lip 38 is in sliding contact with the curved surface portion 45 having an arc-shaped cross section. Therefore, even when the pressure in the internal space 31 rises, the change in the tightening allowance of the tip portion of the second seal lip 38 with respect to the curved surface portion 45 can be suppressed to be small.

[Second Example of Embodiment]
A second example of the embodiment of the present invention will be described with reference to FIGS. 5 to 6.
In the case of this example, the shape of the portion of the seal sliding contact surface 43a where the recesses 52a and 52 are provided is different from that of the first example of the above-described embodiment.

That is, in the case of this example, the seal sliding contact surface 43a is located between the curved surface portion 45 and the cylindrical surface portion 46 in a direction toward the outer side in the axial direction (the side opposite to the internal space 31 in the axial direction). It has an inclined surface portion (tapered surface portion) 53 which is inclined to a straight line and has a linear bus shape. The recesses 52a and 52a are provided at a plurality of positions at equal intervals in the circumferential direction of the inner end portion in the axial direction of the inclined surface portion 53, respectively.

On the other hand, in the case of this example, the tip of the first seal lip 37 is set in a state where the pressure P ₁ in the internal space 31 and the pressure P _{2 in the} space 48 between the first lips are equal to each other (P ₁ = P ₂ ). It is slidably contacted with the outer end portion of the cylindrical surface portion 46 in the axial direction over the entire circumference. Therefore, in the case of this embodiment, the seal of the sliding surface 43a, the pressure P ₁ of the internal space 31 and the pressure P ₂ of the first lip interspaces 48 are equal to each other first by (P ₁ = P ₂₎ state Recessions 52a and 52a are provided at a plurality of locations in the circumferential direction of the portion adjacent to the outer side in the axial direction (the side opposite to the internal space 31) with respect to the portion where the tip portion of the seal lip 37 is in sliding contact.

In the case of the rolling bearing unit for wheel support of this example having the above-described configuration, the inclined surface portion 53 is formed on the outer peripheral surface of the intermediate material by forging the intermediate material for forming the hub body 23. At the same time, the recesses 52a and 52a can be formed.

That is, in this case, on the inner peripheral surface of the mold (forging mold) for performing the forging process, a conical concave surface portion for forming the inclined surface portion 53 and a plurality of conical concave surface portions for forming the respective recesses 52a and 52a. A convex portion of the above is provided. Then, by pushing the intermediate material into the inner diameter side of the mold from the outside in the axial direction, the inclined surface portion 53 and the recesses 52a and 52a are simultaneously formed on the outer peripheral surface of the intermediate material. Since the axially inner ends of the recesses 52a and 52a formed in this way are open in the axial direction, the intermediate material can be subsequently pulled out from the inner diameter side of the mold.

In the case of this example, the forging process for forming the recesses 52a and 52a can be performed separately after the forging process for forming the inclined surface portion 53.

In any case, after the recesses 52a and 52a are formed by forging as described above, the inclined surface portion 53 on which the recesses 52a and 52a are formed is subjected to finishing cutting and grinding. In the case of this example, since the inclined surface portion 53 has a partially conical surface shape, the shapes of the recesses 52a and 52a viewed from the outside in the radial direction are circular toward the inside in the axial direction, for example, as shown in FIG. It becomes a substantially triangular shape (drop shape) in which the width dimension in the direction becomes smaller.

As described above, in the case of this example, since it is easy to form the recesses 52a and 52a, the manufacturing cost can be reduced.
When carrying out the present invention, as shown by the chain line α in FIG. 5, the inclined surface portion 53 may be provided so as to extend inward in the axial direction up to the axial range in which the cylindrical surface portion 46 exists. In this case, the tip end portion of the first seal lip 37 is slidably contacted with the extended portion over the entire circumference.
Other configurations and operations are the same as in the case of the first example of the above-described embodiment.

[Third example of the embodiment]
A third example of the embodiment of the present invention will be described with reference to FIG.
In the case of this example, the point that the seal sliding contact surface 43b is provided on the surface of the sliding contact ring (slinger) 54 formed separately from the hub body 23 is the first example of the above-described embodiment. Different from the case of.

The sliding contact ring 54 has a substantially C-shaped cross section and is formed in an annular shape as a whole by punching and bending a metal plate such as a steel plate having rust preventive performance, and has an outer peripheral surface of the hub body 23. Of these, the outer fitting is fixed to a portion of the rotating side flange 25 adjacent to the inner side in the axial direction.

More specifically, the sliding contact ring 54 has an inner diameter side cylindrical portion 55 and an axial inner end portion continuous with the axial outer end portion of the inner diameter side cylindrical portion 55, and the radial direction toward the outer side in the axial direction. An inner diameter side curved plate portion 56 having an arcuate cross section inclined in a curved direction toward the outside, and a circular ring plate portion in which the radial inner end portion is continuous with the radial outer end portion of the inner diameter side curved plate portion 56. The outside of the arcuate cross-section in which the radial inner end is continuous with the radial outer end of the annular plate portion 57, and the cross-sectional arc shape is curved in the axially inward direction toward the radial outer side. It has a diameter-side curved plate portion 58 and an outer-diameter-side cylindrical portion 59 having an axially outer end portion continuous with an axial inner end portion of the outer diameter side curved plate portion 58. Then, the inner diameter side cylindrical portion 55 is externally fitted and fixed to the portion (cylindrical surface portion 46) adjacent to the inside of the rotation side flange 25 in the axial direction on the outer peripheral surface of the hub main body 23. At the same time, the axial outer surface of the circular plate portion 57 is brought into contact with the radial inner end portion (circular ring surface portion 44) of the axial inner surface of the rotating side flange 25.

Further, in the case of this example, the seal sliding contact surface 43b is composed of an axial inner surface of the annular plate portion 57, an outer peripheral surface of the inner diameter side curved plate portion 56, and an outer peripheral surface of the inner diameter side cylindrical portion 55. There is. In the case of this example, the tip of the first seal lip 37 is placed on the outer peripheral surface of the inner diameter side cylindrical portion 55, and the tip of the second seal lip 38 is placed on the outer peripheral surface of the inner diameter side curved plate portion 56. The tip of the third seal lip 39 is slidably contacted on the inner surface of the annular plate portion 57 in the axial direction over the entire circumference. Further, in this state, between the seal material 33a constituting the seal ring 19a and the seal sliding contact surface 43b, the space between the first lips sandwiched between the first and second seal lips 37, 38. The 48 and the second lip space 49 sandwiched between the second and third seal lips 38 and 39 are formed.

Further, in the present example, of the sealing sliding surface 43 b (the outer peripheral surface of the inner diameter-side cylindrical portion 55), the pressure P ₁ of the internal space 31 and the pressure P ₂ of the first lip interspaces 48 are equal to each other (P ₁ = with respect to the first seal lip 37 tip sliding contact portion in the P ₂₎ state, the plurality of locations to be equiangularly portion adjacent to the axially outward, is recessed respectively radially state A through hole 60 is provided. In the case of this example, each of these through holes 60 corresponds to the thinning portion described in the claims. Each of these through holes 60 is provided so as to penetrate the inner diameter side cylindrical portion 55 in the radial direction.

Further, in the case of this example, the shape of each through hole 60 seen from the outside in the radial direction is a circular shape similar to the recesses 52, 52 shown in FIG. 4A. However, when the present invention is carried out, the shape of each through hole 60 viewed from the outside in the radial direction is an oval shape extending in the circumferential direction similar to the recesses 52 and 52 shown in FIG. 4 (b). Alternatively, various shapes such as an oval shape extending in the axial direction and a polygonal shape similar to the recesses 52 and 52 shown in FIG. 4 (c) can be adopted.

Further, in the case of this example, the sealing material 33a constituting the sealing ring 19a does not have the auxiliary lip 42 (see FIG. 2). Instead, the sealing material 33a brings the radial outer end portion of the outer diameter side covering portion 41 closer to the inner peripheral surface of the outer diameter side cylindrical portion 59 constituting the sliding contact ring 54 via a minute gap. They are facing each other. As a result, a labyrinth seal is formed between the radial outer end of the outer diameter side covering portion 41 and the inner peripheral surface of the outer diameter side cylindrical portion 59.

In the case of this example having the above-described configuration, each through hole 60, which is a thinning portion, can be formed easily and at low cost by press working at the time of forming the sliding contact ring 54.
Other configurations and operations are the same as in the case of the first example of the above-described embodiment.

[Fourth Example of Embodiment]
A fourth example of the embodiment of the present invention will be described with reference to FIG.
In the case of this example, the structure of the seal ring 20 that closes the axial inner end opening of the internal space 31 and the peripheral portion thereof is devised, which is different from the case of the first example of the above-described embodiment.

In the case of this example, the seal ring 20 is combined with the sliding contact ring (slinger) 61 to form a combined seal ring.

Of these, the sliding contact ring 61 has an L-shaped cross section and is formed in an annular shape as a whole by performing press working such as punching and bending on a metal plate such as a steel plate having rust-preventive performance. It has a portion 62 and a ring-shaped rotating side plate portion 63 provided in a state of being bent radially outward from the axial inner end portion of the rotating side cylindrical portion 62. The outer peripheral surface of the rotating side cylindrical portion 62 and the axially outer surface of the rotating side plate portion 63 are designated as the seal sliding contact surface 64. Such a sliding contact ring 61 is supported and fixed to the hub 17 in a state where the rotating side cylindrical portion 62 is fitted to the inner end portion in the axial direction of the inner ring 24 constituting the hub 17 by tightening and fitting.

Further, the seal ring 20 is composed of a core metal 65 and a seal material 66.

Of these, the core metal 65 is formed by punching and bending a metal plate such as a steel plate to form an annular shape as a whole with an L-shaped cross section. The stationary side cylindrical portion 67 and the stationary portion 67 are stationary. It has a substantially circular ring-shaped stationary side plate portion 68 provided in a state of being bent inward in the radial direction from the axially outer end portion of the side cylindrical portion 67. Such a core metal 65 is supported and fixed to the outer ring 16 in a state where the stationary side cylindrical portion 67 is tightly fitted to the inner end portion in the axial direction of the outer ring 16.

The sealing material 66 is made of an elastic material such as an elastomer such as rubber, and is bonded and fixed to the entire circumference of the core metal 65. Such a sealing material 66 has three sealing lips 69 to 71 and a constricted portion 72.

The three seal lips 69 to 71 are arranged in the order of the first seal lip 69, the second seal lip 70, and the third seal lip 71 from the side closer to the internal space 31, and the tip of each is a seal slide. It is slidably contacted with the contact surface 64 all around. More specifically, the tips of the first and second seal lips 69 and 70 are placed on the outer peripheral surface of the rotating side cylindrical portion 62 constituting the seal sliding contact surface 64, and the tip portions of the rotating side plate portion 63 are also outside the axial direction. The tip of the third seal lip 71 is slidably contacted on the side surface over the entire circumference. Further, in this state, between the seal material 66 and the seal sliding contact surface 64, the space 73 between the first lip and the second, which are sandwiched between the first and second seal lips 69 and 70. A second lip space 74 sandwiched between the third seal lips 70 and 71 is formed.

Further, the first seal lip 69 is extended (inclined) in the direction toward the internal space 31 side from the outer diameter side edge which is the base end edge toward the inner diameter side end edge which is the tip edge. As a result, the grease leakage prevention function of the first seal lip 69 is enhanced. Further, the second seal lip 70 and the third seal lip 71 are extended (inclined) in the direction toward the external space side (away from the internal space 31) from the base end edge to the tip end edge, respectively. As a result, the foreign matter intrusion prevention function of the second seal lip 70 and the third seal lip 71 is enhanced.

Further, among the first to third seal lips 69 to 71, the base end portion of the first seal lip 69 arranged at a position in contact with the internal space 31 and the first seal lip 69 opposite to the internal space 31. The base ends of the second seal lips 70 arranged adjacent to each other on the side are connected to each other, and the joints 75 between the base ends of the first and second seal lips 69 and 70 are connected to each other. It is arranged radially inside the gold 65 (the end on the inner diameter side of the stationary side plate portion 68).

The constricted portion 72 is adjacent to the radial outer side of the joint portion 75 between the base end portions of the first and second seal lips 69 and 70 and is closer than the core metal 65 (inner diameter side end portion of the stationary side plate portion 68). It is provided in a portion located inside in the radial direction. The radial outer end of the constricted portion 40 is close to the inner diameter side end of the core metal 65 (rest side plate portion 68). Then, in the case of this example, based on the fact that the first and second seal lips 69 and 70 swing around the constricted portion 72 as the swing center, these first and second seal lips 69, The 70 can move slightly in the axial direction.

Further, in the present example, of the sealing sliding surface 64 (outer peripheral surface of the rotating side cylindrical portion 62), the pressure P ₁ of the internal space 31 and the pressure P ₂ of the first lip interspaces 73 are equal to each other (P ₁ In the state (= P ₂ ), a portion (adjacent portion or a small axial distance) adjacent to the inside in the axial direction (opposite to the internal space 31) is placed with respect to the portion where the tip of the first seal lip 69 is in sliding contact. Through holes 76 are provided at a plurality of locations at equal intervals in the circumferential direction of the separated portions) so as to be recessed in the radial direction. In the case of this example, each of these through holes 76 corresponds to the thinning portion described in the claims.

Further, in the case of this example, the shape of each through hole 76 seen from the outside in the radial direction is a circular shape similar to the recesses 52, 52 shown in FIG. 4A. However, when the present invention is carried out, the shape of each through hole 76 seen from the outside in the radial direction is an oval shape extending in the circumferential direction similar to the recesses 52 and 52 shown in FIG. 4 (b). Alternatively, various shapes such as an oval shape extending in the axial direction and a polygonal shape similar to the recesses 52 and 52 shown in FIG. 4 (c) can be adopted.

In the case of the rolling bearing unit for wheel support of this example having the above-described configuration, the pressure P ₁ in the internal space 31 tends to be higher than the pressure P _{2 in the} space 73 between the first lips (P ₁ > P ₂ ). In the case of, the constricted portion 72 and the first and second seal lips 69 and 70 are formed in the same manner as in the case of the seal ring 19 (see FIG. 2) that closes the axial outer end opening of the internal space 31. By elastic deformation and axial movement, the air in the internal space 31 is introduced into the space between the first lips through the portion of the sliding contact portion between the first seal lip 69 and the seal sliding contact surface 64, which is hung on each through hole 76. It becomes easy to leak to the 73 side. Therefore, even if the pressure P ₁ in the internal space 31 tends to be higher than the pressure P _{2 in the} space 73 between the first lips (P ₁ > P ₂ ), the air in the internal space 31 tends to be higher than the pressure P _{2 in} the first lip space 73. The pressure difference between the internal space 31 and the first lip space 73 can be reduced or eliminated by leaking to the first lip space 73 side through the portion corresponding to. As a result, it is possible to suppress an increase in the frictional force acting on the sliding contact portion between the first seal lip 69 and the sealing sliding contact surface 64.
Other configurations and operations are the same as in the case of the first example or the third example of the above-described embodiment.

The present invention can be implemented by appropriately combining the configurations of the above-described embodiments.
Further, when the present invention is carried out, it is also possible to adopt a configuration in which the thinning portions such as the recesses and through holes are provided only at one position in the circumferential direction of the seal sliding contact surface.

The rolling bearing device of the present invention is applicable not only to a rolling bearing unit for wheel support for drive wheels but also to a rolling bearing unit for wheel support for driven wheels.
Further, the rolling bearing device of the present invention is applicable not only to the rolling bearing unit for wheel support but also to the rolling bearing device incorporated in the rotary support portion of various mechanical devices.

1 Outer ring 2 Hub 3 Rolling body 4 Outer ring orbit 5 Inner ring orbit 6 Internal space 7 Seal ring 8 Core metal 9 Seal material 10 1st seal lip 11 2nd seal lip 12 3rd seal lip 13 Seal sliding contact surface 14 Between 1st lip Space 15 Space between the second lips 16 Outer ring 17 Hub 18 Rolling element 19, 19a Seal ring 20 Seal ring 21 Stationary side flange 22a, 22b Outer ring orbit 23 Hub body 24 Inner ring 25 Rotating side flange 26a, 26b Inner ring orbit 27 Small diameter step 28 Spline hole 29 Caulking part 30a, 30b Cage 31 Internal space 32 Core metal 33, 33a Sealing material 34 Fitting cylinder part 35 Outward flange part 36 Inner diameter support part 37 First seal lip 38 Second seal lip 39 Third seal lip 40 Constricted part 41 Outer diameter side covering part 42 Auxiliary lip 43, 43a, 43b Seal sliding contact surface 44 Circular ring surface part 45 Curved surface part 46 Cylindrical surface part 47 Chamfered part 48 First lip space 49 Second lip space 50 Joint part 51 steps Part 52, 52a Recessed portion 53 Inclined surface part 54 Sliding contact ring 55 Inner diameter side cylindrical part 56 Inner diameter side curved plate part 57 Circular plate part 58 Outer diameter side curved plate part 59 Outer diameter side cylindrical part 60 Through hole 61 Sliding contact ring 62 rotation Side cylindrical part 63 Rotating side side plate part 64 Seal sliding contact surface 65 Core metal 66 Sealing material 67 Static side cylindrical part 68 Static side plate part 69 First seal lip 70 Second seal lip 71 Third seal lip 72 Constriction part 73 First Space between lips 74 Space between second lips 75 Joint 76 Through hole

Claims (3)

An outer diameter side track ring that has an outer ring track on the inner peripheral surface and does not rotate even during use,
An inner ring track that has an inner ring track on the outer peripheral surface and rotates during use,
A plurality of rolling elements rotatably provided between the outer ring track and the inner ring track, and
An internal space existing between the inner peripheral surface of the outer diameter side raceway ring and the outer peripheral surface of the inner diameter side raceway ring and provided with the plurality of rolling elements .
And a seal ring for closing the axial end opening of the internal space,
The seal ring has an annular core metal fixed to the axial end of the outer diameter side raceway ring, and a sealing material fixed to the entire circumference of the core metal.
The sealing member includes a first seal lip that extends from the disposed at a position that comes into contact with the interior space and the base end portion in a direction toward the internal space side as toward the tip portion, the internal to the first seal lip includes a second seal lip arranged at a position adjacent to the space opposite, secure the respective distal end portions of the first seal lip and a second sheet Rurippu, the inner diameter side raceway ring or the inner diameter side race and by sliding the seal sliding surface provided on the surface of the other member,
It was sandwiched between the sealing material and the sealing sliding contact surface between the first sealing lip and the second sealing lip, and was partitioned from the internal space by the first sealing lip. A rolling bearing device in which a space between the first lips is formed .
The sealing member, the first seal lip of the base end portion and having a coupling portion for coupling the proximal end portion of the second sheet Rurippu, and, and the core metal adjacent the radially outer side of the coupling portion It has a constricted part in the part located inward in the radial direction.
Wherein in a state in which there is a pressure equal to the pressure between the first lip between space of the inner space, the seal of the sliding surface, the tip portion of the distal end portion of the first seal lip and sliding contact portion second sheet Rurippu It is characterized in that a thinning portion is provided in a state of being recessed in the radial direction at one or a plurality of locations in the circumferential direction located in the vicinity of the first seal lip, which is a portion between the portion where the surface is in sliding contact. Rolling bearing device. The seal sliding contact surface is provided on the surface of the inner diameter side raceway ring , and the outer diameter dimension is such that at least a part of the seal sliding contact surface faces the side opposite to the internal space in the axial direction. It is an inclined surface that is inclined in the direction of increasing.
The rolling bearing device according to claim 1, wherein the thinning portion is provided on the inclined surface portion. The seal sliding contact surface is provided on the surface of a sliding contact ring which is another member fixed to the inner diameter side raceway ring.
The rolling bearing device according to claim 1, wherein the thinning portion is provided so as to penetrate the sliding contact ring.

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