JP6809195B2 - 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 the plurality of rolling elements 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. ing. 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 left side of each drawing except FIG. 4, which is the outside in the width direction of the vehicle body when assembled to the automobile, and conversely, the center in the width direction of the vehicle body. The right side of each drawing except FIG. 4 on the side 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 end portion which is the base end portion toward the inner diameter side end portion which is the tip end portion. 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 portion to the tip end portion, 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 the plurality of rolling elements 3 and the first to third seal lips 10 to 12 Friction heat is generated at the sliding contact portion (sliding contact portion) between the seal and 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 of the space 15 between the second lips sandwiched between the 12 lips tends to increase.

Here, the second seal lip 11 is inclined in the direction toward the external space side from the base end portion toward the tip end portion. That is, in the posture of the second seal lip 11, the air in the space 15 between the second lips (on the external space side) passes through the sliding contact portion between the second seal lip 11 and the seal sliding contact surface 13, and the space 14 between the first lips 14 On the other hand, the air in the space 14 between the first lips passes through the sliding contact portion between the second seal lip 11 and the sliding contact surface 13 of the seal, and the space 15 between the second lips (external space side). The posture is such that it easily leaks out.

Further, the third seal lip 12 is also inclined in the direction toward the external space side from the base end portion toward the tip end portion. That is, the posture of the third seal lip 12 is such that the air on the external space side does not easily enter the space 15 between the second lips through the sliding contact portion between the third seal lip 12 and the seal sliding contact surface 13. On the other hand, the air in the space 15 between the second lips is in a posture that easily leaks to the external space side through the sliding contact portion between the third seal lip 12 and the seal sliding contact surface 13.

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 possible 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 portion toward the tip end portion. That is, in the posture of the first seal lip 10, the air in the space 14 between the first lips (on the side of the external space) invades the internal space 6 through the sliding contact portion between the first seal lip 10 and the seal sliding contact surface 13. On the other hand, the posture is such that the air in the internal space 6 does not easily leak into the space 14 between the first lips (on the external space side) through the sliding contact portion between the first seal lip 10 and the seal sliding contact surface 13. It has become.

Therefore, even if the pressure in the internal space 6 tends to increase, the air in the internal space 6 will pass through the sliding contact portion between the first seal lip 10 and the seal sliding contact surface 13 and the space 14 between the first lips (external space). Since it is not efficiently discharged to the side), it is difficult to suppress the increase in the pressure in the internal space 6.

Then, when the pressure in the internal space 6 rises in this way, the pressure in the internal space 6 elastically deforms the first seal lip 10 so as to be pressed (attached) to the seal sliding contact surface 13, and these first seal lips 10 are elastically deformed. There arises a problem that the frictional force acting on the sliding contact portion between the seal lip 10 and the sealing sliding contact surface 13 increases.

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 in this way, the frictional heat generated at the sliding contact portion increases and is affected by this frictional heat. The temperature of the first lip space 14 tends to rise further, which is easy. Then, when the rotation of the hub 2 is stopped from this state and the bearing temperature is lowered, a strong negative pressure tends to be generated in the space 14 between the first lips. 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 sliding contact surface 13, and the first and second seal lips 10 and 11 and the seal friction are formed. There is a problem that the frictional force acting on the sliding contact portion with the contact surface 13 increases.

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, and a seal ring.
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 seal ring is an opening at the axial end of an internal space provided with a plurality of rolling elements 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. It 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 to 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 of the lip. Then, the tips of the first and second seal lips are slidably contacted with the surface of the inner diameter side raceway ring or the surface of the sliding contact ring fixed to the inner diameter side raceway ring.
Further, the rigidity of the first seal lip changes in the circumferential direction. In other words, the rigidity of the first seal lip is not uniform in the circumferential direction.

Further, when the present invention is carried out, for example, tongue pieces provided at one or more locations in the circumferential direction of the first seal lip in a state of extending inward in the radial direction from the core metal (for example). It is possible to adopt a configuration in which the first seal lip is embedded (in a state of invading from the base end side) .
Further, although it is out of the technical scope of the present invention, thick portions having a thickness larger than that of the portions adjacent to each other in the circumferential direction are provided at one or a plurality of locations in the circumferential direction of the first seal lip. It is possible to adopt the configuration that has been adopted.

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, a cross-sectional view (a) and a cross-sectional view (a) showing the radial inner end of the seal ring on the outer side in the axial direction when the tongue piece of the core metal and the thick portion of the seal material are not present are cut at a circumferential position. FIG. 3B is a cross-sectional view when the tongue piece and the thick portion are cut at a position in the circumferential direction. Similarly, a schematic diagram for explaining how the first seal lip deforms before and after the hub rotates. An enlarged view corresponding to a part B of FIG. 1 showing a concrete seal structure according to a second example of the embodiment of the present invention. Similarly, a cross-sectional view (a) showing the radial inner end of the seal ring inward in the axial direction when the core metal is cut at a circumferential position where the tongue piece does not exist, and the circumference where the tongue piece exists. FIG. 5 (b) is a cross-sectional view when cutting at a directional position. The same figure as FIG. 2 regarding one example of the reference example related to this invention. Similarly, there is a cross-sectional view (a) showing the radial inner end of the seal ring on the outer side in the axial direction when the seal material is cut at a circumferential position where the thick portion of the seal material does not exist, and the thick portion exists. FIG. 3B is a cross-sectional view when the product is cut at a position in the circumferential direction. 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 a drive wheel, 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 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 main 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.

The sealing ring 19 on the outer side in the axial direction is composed of a core metal 32 and a sealing 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 35 bent radially outward from the axial outer end of 34, and the fitting cylinder 34 is folded back axially outward and radially inward from the axial inner end. From one or more points in the circumferential direction (for example, 2 to 8 places at equal intervals in the circumferential direction) of the bent inner diameter support portion 36 and the inner peripheral edge of the inner peripheral support portion 36, inward and axially, respectively. It has a substantially rectangular plate-shaped tongue piece 37 provided so as to extend inward. That is, the tongue piece 37 is curvedly inclined in the axially inward direction from the radial outer end portion, which is the base end portion, to the radial inner end portion, which is the tip end portion. 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 outward 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 sealing lips 38 to 40, an outer diameter side covering portion 41, and an auxiliary lip 42.

The three seal lips 38 to 40 are arranged in the order of the first seal lip 38, the second seal lip 39, and the third seal lip 40 from the side closer to the internal space 31, and the tip of each is the 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 surface portion (corner R portion) having a concave arc shape as a bus, 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 direction. 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. Then, the tip of the first seal lip 38 is placed on the cylindrical surface 46, the tip of the second seal lip 39 is placed on the curved surface 45, and the tip of the third seal lip 40 is placed on the annular surface 44. It is in sliding contact. In FIG. 2, the shape of the sealing material 33 including the first to third sealing lips 38 to 40 is shown in the free state of the sealing material 33.

Further, in this state, between the seal material 33 and the seal sliding contact surface 43, the space 47 between the first lip and the second, which are sandwiched between the first and second seal lips 38, 39, and the second. A second lip space 48 sandwiched between the third seal lips 39 and 40 is formed.

Further, in the case of this example, the first seal lip 38 extends (inclines) in the direction toward the internal space 31 side from the outer diameter side end portion which is the base end portion to the inner diameter side end portion which is the tip end portion. ). As a result, the grease leakage prevention function of the first seal lip 38 is enhanced. Further, the second seal lip 39 and the third seal lip 40 are extended (tilted) in the direction toward the external space side (away from the internal space 31) from the base end portion to the tip end portion, respectively. As a result, the foreign matter intrusion prevention function of the second seal lip 39 and the third seal lip 40 is enhanced.

Further, in the case of this example, one or a plurality of base halves of the first seal lip 38 having the same phase as the tongue piece 37 constituting the core metal 32 in the circumferential direction are adjacent to both sides in the circumferential direction. A thick portion 49 is provided, which has a larger thickness than the portion and the portion adjacent to the tip side. On the axial inner surface (diametric outer surface) of the first seal lip 38, the portion corresponding to the thick portion 49 bulges in the axial direction (diametrically outer) as compared with the peripheral portion. In the case of this example, the first half of the tongue piece 37 is embedded in such a thick portion 49 in a state of invading from the base end side of the first seal lip 38. Therefore, the rigidity of the first seal lip 38 is larger in the circumferential direction portion where the thick portion 49 is provided and the tongue piece 37 is embedded, as compared with the other circumferential direction portions. ..

The outer diameter side covering portion 41 is provided so as to cover the axial outer surface and the radial outer end surface of the outward flange portion 35 constituting the core metal 32, and has a diameter larger than that of the outer peripheral surface of the axial outer end portion of the outer ring 16. It protrudes outward in the 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 closer to 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 end portion of the auxiliary lip 42 is inclined in a curved shape in the direction toward the inner side in the axial direction toward the inner side in the radial direction provided at the portion near the inner end in the radial direction on the inner side surface in the axial direction of the rotation side flange 25. The step portion 50 is brought close to and opposed to the step portion 50 via a minute gap. As a result, a labyrinth seal is formed on the closely opposed portions.

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 outer ring race tracks 22a and 22b and the inner ring raceways 26a and 26b and the rolling contact portions between the plurality of rolling elements 18 and 18 become , Friction heat is generated at the sliding contact portion (sliding contact portion) between the first to third seal lips 38 to 40 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 47, and the second lip space 48 tend to rise.

Here, the second seal lip 39 is inclined in the direction toward the external space side from the base end portion toward the tip end portion. That is, in the posture of the second seal lip 39, the air in the second lip space 48 (external space side) passes through the sliding contact portion between the second seal lip 39 and the seal sliding contact surface 43, and the first lip space 47 On the other hand, the air in the space 47 between the first lips passes through the sliding contact portion between the second seal lip 39 and the sliding contact surface 43 of the seal, and the space 48 between the second lips (external space side). The posture is such that it easily leaks out.

Further, the third seal lip 40 is also inclined in the direction toward the external space side from the base end portion toward the tip end portion. That is, the posture of the third seal lip 40 is such that the air on the external space side does not easily enter the space 48 between the second lips through the sliding contact portion between the third seal lip 40 and the seal sliding contact surface 43. On the other hand, the air in the space 48 between the second lips is in a posture that easily leaks to the external space side through the sliding contact portion between the third seal lip 40 and the seal sliding contact surface 43.

Therefore, even when the pressure in the spaces 47 and 48 between the first and second lips tends to increase, the air in the spaces 47 and 48 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 39 and 40 and the sealing sliding contact surface 43, it is easy to suppress an increase in pressure in the spaces 47 and 48 between the first and second lips.

On the other hand, the first seal lip 38 is inclined in the direction toward the internal space 31 side from the base end portion toward the tip end portion. That is, in the posture of the first seal lip 38, the air in the space 47 between the first lips (external space side) invades the internal space 31 side through the sliding contact portion between the first seal lip 38 and the seal sliding contact surface 43. On the other hand, the air in the internal space 31 is in an easy posture, but it is difficult for the air in the internal space 31 to leak into the space 47 between the first lips (external space side) through the sliding contact portion between the first seal lip 38 and the seal sliding contact surface 43. It has become.

However, in the case of this example, when the hub 17 rotates, the surface pressure of the sliding contact portion between the first seal lip 38 and the sealing sliding contact surface 43 is partially reduced or lost. Then, through this portion, the air in the internal space 31 easily leaks into the space 47 between the first lips (on the external space side). This point will be described with reference to FIG.

FIG. 4 is a schematic view of the sliding contact portion between the first seal lip 38 and the seal sliding contact surface 43 as viewed from the axial direction, and in the upper half portion (A), the first seal lip 38 has a thick portion 49. In the structure of the comparative example in which the tongue piece 37 is not embedded and does not exist, the lower half (B) is a book in which the thick portion 49 is present in the first seal lip 38 and the tongue piece 37 is embedded. The structure of each example is shown. In FIG. 4, radial two-dot chain lines existing at a plurality of locations in the circumferential direction of the first seal lip 38 are virtual to make it easier to understand the amount of torsional deformation of the first seal lip 38 in the circumferential direction. It represents a shape line.

When the seal sliding contact surface 43 rotates with the rotation of the hub 17, a frictional force in the rotational direction acts from the seal sliding contact surface 43 to the tip end portion (diameter inner end portion) of the first seal lip 38.

At this time, in the case of the structure of the comparative example shown in the upper half (A) of FIG. 4, the thick portion 49 does not exist in the first seal lip 38 and the tongue piece 37 is not embedded. The rigidity of the first seal lip 38 is uniform in the circumferential direction. Therefore, the amount of torsional deformation in the circumferential direction generated in the first seal lip 38 due to the frictional force in the rotational direction is uniform as a whole as shown in (a) → (b) of FIG. 4 (A). Become.

On the other hand, in the case of the structure of this example shown in the lower half (B) of FIG. 4, the thick portion 49 exists in the first seal lip 38 and the tongue piece 37 is embedded. The rigidity of the first seal lip 38 is larger in the circumferential direction portion in which the thick portion 49 is present and the tongue piece 37 is embedded, as compared with the other circumferential direction portions. Therefore, the amount of torsional deformation in the circumferential direction generated in the first seal lip 38 due to the frictional force in the rotational direction is determined by the thick portion 49 as shown in (a) → (b) of FIG. 4 (B). In the circumferential portion that is present and in which the tongue piece 37 is embedded, it is smaller than the other circumferential portions, or becomes substantially zero.

Along with this, the α portion of the first seal lip 38 adjacent to the thick portion 49 and the tongue piece 37 on the front side in the rotational direction is in a state of being stretched in the circumferential direction by the frictional force. Then, in this α portion, the surface pressure of the sliding contact portion with the seal sliding contact surface 43 is higher than that of the other portions.

On the other hand, of the first seal lip 38, the β portion adjacent to the thick portion 49 and the tongue piece 37 on the rear side in the rotational direction is in a state of being crushed in the circumferential direction by the frictional force. Then, in this β portion, the surface pressure of the sliding contact portion with the seal sliding contact surface 43 becomes lower or lost as compared with other portions (a minute gap is generated in this sliding contact portion).

Therefore, in the case of this example, the internal space 31 and the first lip space 47 are in communication with each other through the minute gap generated in the sliding contact portion of the β portion, and the internal space 31 and the first lip space 47 ( Air can move between the outside space side).

Therefore, in the case of this example, even when the pressure in the internal space 31 tends to increase, the inside is passed through a minute gap generated in the sliding contact portion between the β portion of the first seal lip 38 and the sealing sliding contact surface 43. Since the air in the space 31 leaks into the space 47 between the first lips (on the side of the external space), the increase in pressure in the internal space 31 can be suppressed. As a result, the pressure of the internal space 31 prevents the first seal lip 38 from being elastically deformed so as to be pressed (attached) to the seal sliding contact surface 43, and the first seal lip 38 and the seal sliding contact. It is possible to suppress an increase in the frictional force acting on the sliding contact portion with the surface 43.

Further, as a result, it is possible to suppress an increase in the frictional heat generated at the sliding contact portion between the first seal lip 38 and the seal sliding contact surface 43, so that the space 47 between the first lips is easily affected by the frictional heat. It is possible to prevent the temperature from rising further. Therefore, when the rotation of the hub 17 is stopped from this state and the bearing temperature is lowered, the magnitude of the negative pressure generated in the space 47 between the first lips can be suppressed. As a result, it is possible to suppress elastic deformation of the first and second seal lips 38 and 39 so as to stick to the seal sliding contact surface 43 due to this negative pressure, and these first and second seal lips 38 and 39 It is possible to suppress an increase in the frictional force acting on the sliding contact portion with the seal sliding contact surface 43.

[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 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 constitutes a combined seal ring by combining with the sliding contact ring (slinger) 51.

Of these, the sliding contact ring 51 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 52 and a ring-shaped rotating side plate portion 53 provided in a state of being bent radially outward from the axial inner end portion of the rotating side cylindrical portion 52. The outer peripheral surface of the rotating side cylindrical portion 52 and the axially outer surface of the rotating side plate portion 53 are designated as the seal sliding contact surface 54. Such a sliding contact ring 51 is supported and fixed to the hub 17 in a state where the rotating side cylindrical portion 52 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 55 and a seal material 56.

Of these, the core metal 55 has an L-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. The stationary side cylindrical portion 57 and the stationary portion 57 are stationary. A substantially circular ring-shaped stationary side plate 58 provided in a state of being bent inward in the radial direction from the axial outer end of the side cylindrical portion 57, and one or a plurality of circumferential directions of the inner peripheral edge of the stationary side plate 58. It has a substantially rectangular plate-shaped tongue piece 59 provided in a state of extending inward in the radial direction and outward in the axial direction from (for example, 2 to 8 locations at equal intervals in the circumferential direction). There is. That is, the tongue piece 59 is curvedly inclined in the axially outward direction from the radial outer end portion which is the base end portion to the radial inner end portion which is the tip end portion. Such a core metal 55 is supported and fixed to the outer ring 16 in a state where the stationary side cylindrical portion 57 is tightly fitted to the inner end portion in the axial direction of the outer ring 16.

The sealing material 56 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 55. Such a sealing material 56 has three sealing lips 60 to 62.

The three seal lips 60 to 62 are arranged in the order of the first seal lip 60, the second seal lip 61, and the third seal lip 62 from the side closer to the internal space 31, and the tip of each is a seal slide. It is slidly contacted with the contact surface 54 all around. More specifically, the tips of the first and second seal lips 60 and 61 are placed on the outer peripheral surface of the rotating side cylindrical portion 52 constituting the seal sliding contact surface 54, and the tip portions of the rotating side plate portions 53 are also outside the axial direction. The tip of the third seal lip 62 is slidably contacted on the side surface over the entire circumference. In FIG. 5, the shape of the sealing material 56 including the first to third sealing lips 60 to 62 is shown in the free state of the sealing material 56.

Further, in this state, between the seal material 56 and the seal sliding contact surface 54, the space 63 between the first lip and the second, which are sandwiched between the first and second seal lips 60 and 61, and the second. A second lip space 64 sandwiched between the third seal lips 61 and 62 is formed.

Further, the first seal lip 60 is extended (inclined) in the direction toward the internal space 31 side from the outer diameter side end portion which is the base end portion toward the inner diameter side end portion which is the tip end portion. As a result, the grease leakage prevention function of the first seal lip 60 is enhanced. Further, the second seal lip 61 and the third seal lip 62 are extended (inclined) in the direction toward the external space side (away from the internal space 31) from the base end portion to the tip end portion, respectively. As a result, the foreign matter intrusion prevention function of the second seal lip 61 and the third seal lip 62 is enhanced.

Further, in the case of this example, one or a plurality of base halves of the first seal lip 60 having the same phase as the tongue piece 59 constituting the core metal 55 in the circumferential direction are adjacent to both sides in the circumferential direction. A thick portion 65 is provided, which has a larger thickness than the portion and the portion adjacent to the tip side. The portion of the first seal lip 60 corresponding to the thick portion 65 bulges outward in the axial direction (outer in the radial direction) as compared with the surrounding portion of the outer surface in the axial direction (outer surface in the radial direction). Then, in the case of this example, the first half of the tongue piece 59 is embedded in such a thick portion 65 in a state of invading from the base end side of the first seal lip 60. Therefore, the rigidity of the first seal lip 60 is larger in the circumferential direction portion where the thick portion 65 is provided and the tongue piece 59 is embedded, as compared with the other circumferential direction portions. ..

In the case of the rolling bearing unit for wheel support of this example having the above-described configuration, when the seal sliding contact surface 54 rotates with the rotation of the hub 17, the seal ring 19 (which closes the axial outer end opening of the internal space 31) ( For the same reason as in the case of FIGS. 2 to 4), the portion of the first seal lip 60 adjacent to the thick portion 65 and the tongue piece 59 on the rear side in the rotation direction (corresponding to the β portion in FIG. 4). In the portion), the surface pressure of the sliding contact portion with the seal sliding contact surface 54 becomes lower or lost as compared with other portions (a minute gap is generated in this sliding contact portion).

Therefore, in the case of this example, even if the pressure in the internal space 31 tends to increase as the bearing temperature rises, the air in the internal space 31 passes through the minute gap in the space 63 between the first lips ( By leaking to the external space side), the increase in pressure in the internal space 31 can be suppressed. As a result, the pressure of the internal space 31 prevents the first seal lip 60 from being elastically deformed so as to be pressed (attached) to the seal sliding contact surface 54, and the first seal lip 60 and the seal sliding contact. It is possible to suppress an increase in the frictional force acting on the sliding contact portion with the surface 54.
Other configurations and operations are the same as in the case of the first example of the above-described embodiment.

[ One example of reference example ]
An example of a reference example related to the present invention will be described with reference to FIGS. 7 to 8.
In the case of this reference example, the configuration of a part of the seal ring 19a on the outer side in the axial direction is different from that of the first example of the above-described embodiment.

In the case of this reference example, the seal ring 19a does not have the tongue piece 37 (see FIGS. 2 to 3) at the radial inner end of the core metal 32a, and the first seal lip 38a constituting the seal material 33a The tongue piece 37 is not embedded in the thick portion 49a. That is, in the case of this reference example, the thick portion 49a is composed of only the elastic material that constitutes the sealing material 33a as a whole.

Also in the case of this reference example as described above, the rigidity of the first seal lip 38a is larger in the circumferential direction portion where the thick portion 49a is provided than in the other circumferential direction portions. In the case of this reference example, the rigidity of the portion provided with the thick portion 49a can be adjusted by changing the thickness dimension of the thick portion 49a. Therefore, also in the case of this reference example, the frictional force acting on the sliding contact portion between the first seal lip 38a and the sealing sliding contact surface 43 due to the same action (reason) as in the case of the first example of the above-described embodiment. However, it can be suppressed from increasing with the change of the bearing temperature.

Further, in the case of this reference example, since the tongue piece 37 is not provided on the core metal 32a, the work of forming the tongue piece 37 becomes unnecessary, and the tongue piece 37 and the thick wall are thickened when the sealing material 33a is vulcanized. Since the work of phase matching with the portion 49a becomes unnecessary, the seal ring 19a can be easily manufactured.
Other configurations and operations are the same as in the case of the first example of the above-described embodiment.

Although not shown, the tongue piece 59 is omitted as a modification of the structure of the second example of the embodiment shown in FIGS. 5 to 6 above, although it is outside the technical scope of the present invention. It is also possible to adopt a structure in which the entire thick portion 65 is composed of only the elastic material constituting the sealing material 56.

Further, in the case of carrying out the present invention, when adopting a configuration in which a tongue piece provided on the core metal is embedded in one or a plurality of places in the circumferential direction of the first seal lip, among the first seal lips, The portion in which the tongue piece is embedded does not necessarily have to be a thick portion, and may have the same thickness as the surrounding portion.

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 element 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, 32a Core metal 33, 33a Sealing material 34 Fitting cylinder part 35 Outward flange part 36 Inner diameter support part 37 Tongue piece 38, 38a First seal lip 39 Second seal Lip 40 Third seal lip 41 Outer diameter side cover 42 Auxiliary lip 43 Seal sliding contact surface 44 Circular ring surface 45 Curved surface 46 Cylindrical surface 47 First lip space 48 Second lip space 49, 49a Thick part 50 steps Part 51 Sliding contact ring 52 Rotating side cylindrical part 53 Rotating side side plate part 54 Seal sliding contact surface 55 Core metal 56 Sealing material 57 Resting side cylindrical part 58 Static side plate part 59 Tongue piece 60 First seal lip 61 Second seal lip 62 Third seal lip 63 Space between first lips 64 Space between second lips 65 Thick part

Claims (1)

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
A seal ring for closing the axial end opening of the internal space provided with the plurality of rolling elements 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 is provided. ,
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 material is arranged at a position in contact with the internal space and extends from the base end portion toward the tip end portion toward the internal space side, and the first sealing lip and the first sealing lip. It has a second seal lip arranged adjacent to the internal space on the opposite side, and the tips of the first and second seal lips are attached to the surface of the inner diameter side race ring or the inner diameter side race ring. It is slidably contacted with the surface of the fixed sliding contact ring.
The rigidity of the first seal lip changes with respect to the circumferential direction.
A tongue piece provided in a state of extending inward in the radial direction from the core metal is embedded in one or a plurality of locations in the circumferential direction of the first seal lip.
Rolling bearing device.

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