JP2018150972A - Rolling bearing unit for wheel support - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further reliably prevent water from entering an internal space, in a structure provided with a thin wall part in an axial outside part of an outer ring.SOLUTION: In a wheel supporting rolling bearing unit, a core metal 2a constituting a seal ring 1a includes: a fitting cylindrical part 4a internally fitted to an axial outside inner peripheral surface of an outer ring 9; and an inner diameter-side annular part 5a bent radially inward from an axial outer end part of the fitting cylindrical part 4a. The axial outer end part of the fitting cylindrical part 4a is positioned on an outside relative to a thin wall part 12 of the outer ring 9 relating to an axial direction.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a wheel bearing rolling bearing unit for rotatably supporting a wheel of an automobile with respect to a suspension device.

  An automobile wheel and a braking rotator are rotatably supported by a suspension device by a wheel bearing rolling bearing unit. The wheel support rolling bearing unit includes an outer ring having an outer ring raceway on an inner peripheral surface, a hub having an inner ring raceway on an outer peripheral surface, and a plurality of rolling elements provided between the outer ring raceway and the inner ring raceway. A moving body. The outer ring is supported and fixed to the suspension device, and the wheel and the brake rotating body are supported and fixed to the hub.

  As a rolling bearing unit for supporting wheels, in order to close the axially outer opening of the inner space existing between the inner peripheral surface of the outer ring and the outer peripheral surface of the hub, Conventionally, a structure in which a seal ring is mounted between the outer peripheral surface of the part is also known.

  Note that “outside” with respect to the axial direction refers to the outside in the width direction of the vehicle in the assembled state in the automobile, and corresponds to the left side in each figure. On the contrary, the right side of each figure, which is the center side in the width direction of the vehicle in the assembled state in the automobile, is referred to as “inside” in the axial direction.

  FIG. 6 shows an example of a wheel support rolling bearing unit described in JP-A-2015-227673. The seal ring 1 includes an annular cored bar 2 and a sealing material 3 joined to the cored bar 2. The cored bar 2 includes a cylindrical fitting tube portion 4 and an inner diameter side ring that is folded back in a U shape from the inner end in the axial direction of the fitting tube portion 4 toward the radially inner side and the axially outer side. A portion 5 and an outer-diameter-side annular portion 6 that is bent and extends radially outward from the axially outer end of the fitting tube portion 4. The sealing material 3 is vulcanized and bonded to the core metal 2 and includes three sealing lips 7.

  The seal ring 1 as described above is configured such that the fitting cylinder portion 4 of the core metal 2 is fitted and fixed to the inner circumferential surface of the outer side of the outer ring 9 by an interference fit. It is attached to. With the seal ring 1 mounted on the inner diameter side of the outer side in the axial direction of the outer ring 9, the seal lip 7 is in sliding contact with the surface of the hub 8 over the entire circumference.

  In the illustrated example, a groove 10 that is recessed radially inward is provided on the outer circumferential surface of the outer side of the outer ring 9 in the axial direction. Since such a concave groove 10 is provided, it adheres to the outer peripheral surface of the outer ring 9 during traveling of the vehicle, and this outer peripheral surface is transmitted from the inner side in the axial direction to the outer side. Foreign matter such as rain water and muddy water reaching the surface is guided to the road surface side by the concave groove 10 and is easily discharged to the outside.

JP2015-227673A

  In order to mount the seal ring 1 as described above on the inner diameter side of the outer side portion of the outer ring 9, the fitting tube portion 4 of the core metal 2 is directed from the outer side of the outer ring 9 toward the inner side in the axial direction. If it press-fits in the axial direction outer side inner peripheral surface, the press-fitting flaw may be formed in the outer peripheral surface of the fitting tube portion 4 in the axial direction. In such a press-fitting wound, the greater the rigidity in the radial direction of the outer ring 9 and the fitting cylinder part 4, the larger the surface pressure of the fitting part between the outer peripheral surface of the fitting cylinder part 4 and the inner peripheral surface of the outer ring 9. So it is easy to form.

  In the structure shown in the drawing, among the axially outer portions of the outer ring 9, the radial thickness of the thick portion 11 existing outside the concave groove 10 in the axial direction is the thin portion existing on the inner diameter side of the concave groove 10. It is thicker than 12 radial thicknesses. For this reason, the rigidity in the radial direction of the outer ring 9, particularly the rigidity with respect to the force in the direction of expanding the inner diameter of the outer ring 9, is determined by the inner space 13 existing between the inner peripheral surface of the outer ring 9 and the outer peripheral surface of the hub 8. The thick part 11 on the side closer to the axially outer opening is larger than the thin part 12 on the side far from the axially outer opening.

  On the other hand, the cored bar 2 is provided with an inner diameter side annular portion 5 that is folded back in a U shape from the inner end in the axial direction of the fitting cylinder portion 4 toward the radially inner side and the axially outer side. For this reason, the rigidity with respect to the radial direction of the fitting cylinder part 4, particularly the rigidity with respect to the force in the direction of reducing the outer diameter of the fitting cylinder part 4, When it press-fits, it becomes the largest in the axial direction inner end part of the fitting cylinder part 4 initially press-fitted, and it becomes small as it goes to an axial direction outward.

  Therefore, when the fitting tube portion 4 is press-fitted, the surface pressure between the outer peripheral surface of the fitting tube portion 4 and the inner peripheral surface of the outer side of the outer ring 9 is the same as the outer peripheral surface of the inner end portion of the fitting tube portion 4 in the axial direction. It becomes large in the initial stage of the press-fitting work in which the inner peripheral surface of the thick portion 11 is fitted. For this reason, from the initial stage of the press-fitting work of the fitting cylinder part 4, the press-fitting defect is easily formed on the outer peripheral surface of the fitting cylinder part 4. If a press-fitting flaw is formed on the outer peripheral surface of the fitting cylinder portion 4 in the initial stage of the press-fitting operation, the press-fitting flaw increases as it extends in the axial direction as the press-fitting operation proceeds. As a result, press-fitting flaws are formed on the outer peripheral surface of the fitting cylinder portion 4 over the entire length in the axial direction.

  Further, when the fitting cylinder portion 4 is press-fitted into the inner circumferential surface of the outer ring 9 in the axial outer side portion, the outer circumferential surface of the axial inner end portion having the greatest radial rigidity among the fitting cylinder portions 4 is The outer ring 9 is first press-fitted into the inner peripheral surface of the outer side in the axial direction. For this reason, the slidable contact length between the axial inner end portion outer peripheral surface of the fitting cylinder portion 4 and the axial outer side inner peripheral surface of the outer ring 9 is increased, and the shaft of the fitting cylindrical portion 4 is out of the press-fitting wound. There is a possibility that the depth of the portion formed on the outer peripheral surface of the inner end portion in the direction becomes deeper or the width in the circumferential direction of this portion becomes larger. When the press-fitting of the fitting cylinder part 4 is completed and the seal ring 1 is mounted on the inner diameter side of the outer side part of the outer ring 9 in the axial direction, the outer peripheral surface of the inner side part in the axial direction of the fitting cylinder part 4 is The inner wall of the thin portion 12 is fitted. When a large press-fitting flaw is formed on the outer peripheral surface of the inner end portion in the axial direction of the fitting tube portion 4, the outer peripheral surface of the inner end portion in the axial direction of the fitting tube portion 4 and the thin portion 12 corresponding to the presence of the press-fitting flaw. The contact area with the inner peripheral surface of the is reduced. Since the rigidity in the radial direction of the thin-walled portion 12 is small, the surface pressure between the outer peripheral surface in the axial direction inner end portion of the fitting tube portion 4 and the inner peripheral surface of the thin-walled portion 12 is fitted to be fitted to each other at the initial stage of press-fitting operation. It becomes smaller than the surface pressure between the outer peripheral surface of the axially inner end portion of the combined tube portion 4 and the inner peripheral surface of the thick portion 11. Therefore, there is a possibility that the fitting force of the outer peripheral surface of the inner end portion in the axial direction of the fitting cylinder portion 4 with respect to the inner peripheral surface of the outer side portion of the outer ring 9 cannot be secured sufficiently.

  A press-fitting wound is formed over the entire length in the axial direction of the outer peripheral surface of the fitting cylindrical portion 4, or sufficient fitting force is secured on the outer peripheral surface of the inner end portion in the axial direction of the fitting cylindrical portion 4 with respect to the inner peripheral surface of the outer ring 9 in the axial direction. If it is not possible, there is a possibility that the sealing performance of the fitting portion between the outer peripheral surface of the fitting cylinder portion 4 and the inner peripheral surface of the outer side of the outer ring 9 cannot be sufficiently ensured. As a result, the foreign matter that has reached the outer peripheral surface of the outer ring 9 in the axial direction is an abutting portion between the metal surfaces, and the inner surface in the axial direction of the outer diameter side annular portion 6 and the outer end surface in the axial direction of the outer ring 9. If it reaches the outer peripheral surface of the axially outer end portion of the fitting tube portion 4 through the gap, there is a risk of entering the internal space 13 through press-fitting.

  In view of the circumstances as described above, the present invention sufficiently secures the sealing performance of the fitting portion between the outer peripheral surface of the fitting cylindrical portion constituting the core metal of the seal ring and the inner peripheral surface of the outer side in the axial direction of the outer ring. The purpose is to realize a structure that is easy to do.

The wheel bearing rolling bearing unit of the present invention includes an outer ring, a hub, a plurality of rolling elements, and a seal ring.
The outer ring has an outer ring raceway provided on the inner peripheral surface, and a thin part provided on the entire outer periphery in the axial direction.
The hub has an inner ring raceway provided on an outer peripheral surface.
The plurality of rolling elements are rotatably provided between the outer ring raceway and the inner ring raceway.
The seal ring closes the axially outer opening of the internal space existing between the inner peripheral surface of the outer ring and the outer peripheral surface of the hub, and includes an annular cored bar and an elastic material reinforced by the cored bar. And a sealing material made of material.

  In the first aspect of the present invention, the radial thickness of the thin portion is smaller than at least a portion adjacent to the axially outer side of the thin portion, or a portion adjacent to both axial sides of the thin portion, A fitting tube portion in which the core metal is fitted on the inner peripheral surface of the outer side in the axial direction of the outer ring; and an inner diameter side annular portion bent inward in the radial direction from the axial outer end portion of the fitting tube portion; And the axially outer end portion of the fitting tube portion is located outside the thinned portion with respect to the axial direction, and the axially inner end portion of the fitting tube portion of the thinned portion is Located on the inner diameter side.

  In the second aspect of the present invention, the radial thickness of the thin portion is smaller than at least a portion adjacent to the inner side in the axial direction of the thin portion, or a portion adjacent to both axial sides of the thin portion, A fitting tube portion in which the core metal is fitted on the inner circumferential surface of the outer side in the axial direction of the outer ring; and an inner diameter side annular portion bent inward in the radial direction from the axial inner end portion of the fitting tube portion; The inner end of the fitting tube portion in the axial direction is located on the inner side of the thin portion with respect to the axial direction. And the internal diameter of the axial direction outer end part of the said outer ring which exists in the outer side rather than the said thin part regarding an axial direction is larger than the internal diameter of the said thin part.

  When the second aspect of the present invention is carried out, the inner diameter of the inner peripheral surface of the outer end portion in the axial direction of the outer ring existing outside the thin portion in the axial direction increases toward the outer side in the axial direction. It is preferable to adopt a configuration inclined in the direction.

  In the case of carrying out the second aspect of the present invention, the core bar has an outer diameter side annular portion that bends and extends radially outward from the axial outer end portion of the fitting tube portion. A configuration in which the inner surface in the axial direction of the outer diameter side annular portion is abutted against the outer end surface in the axial direction of the outer ring directly or via the sealing material can be employed.

  When carrying out the present invention, the outer circumferential surface of the outer ring in the axial direction is provided with a radially indented groove on the outer circumferential surface of the outer ring, and the thin-walled portion is the outer side in the axial direction of the outer ring. Among these, it is preferable that it is comprised by the part which exists in the internal diameter side of the said ditch | groove.

  In other words, the rolling bearing unit for supporting a wheel according to the present invention is configured such that when the fitting cylindrical portion of the core metal constituting the seal ring is press-fitted into the inner peripheral surface of the outer side in the axial direction of the outer ring, the fitting is started from the initial stage of the press-fitting operation. In order to prevent the press-fitting wound from being formed on the outer peripheral surface of the joint tube portion, at the initial stage of the press-fitting operation, the outer peripheral surface of the portion having a large radial rigidity in the fitting tube portion and the outer ring The inner peripheral surface of the portion having a large rigidity in the radial direction is not fitted.

  According to the rolling bearing unit for supporting a wheel of the present invention as described above, when the outer peripheral surface of the fitting cylinder part constituting the core metal of the seal ring is press-fitted into the inner peripheral surface of the outer side in the axial direction of the outer ring, the fitting is performed. It is possible to prevent the press-fitting wound from being formed over the entire length in the axial direction on the outer peripheral surface of the joint tube portion. As a result, it is possible to sufficiently ensure the sealing performance of the fitting portion between the outer peripheral surface of the fitting cylinder portion and the inner peripheral surface of the outer side in the axial direction of the outer ring.

FIG. 1 is a cross-sectional view showing a first example of an embodiment of the present invention. FIG. 2 is an enlarged view of a portion X in FIG. FIG. 3 is a view similar to FIG. 2 showing a second example of the embodiment of the present invention. FIG. 4 is a view similar to FIG. 2, showing a third example of the embodiment of the present invention. FIG. 5 is a view similar to FIG. 2, showing a fourth example of the embodiment of the present invention. FIG. 6 is a view similar to FIG. 2 showing an example of a conventional structure.

[First example of embodiment]
1 and 2 show a first example of an embodiment of the present invention. The wheel support rolling bearing unit 14 of this example includes an outer ring 9, a hub 8a, a plurality of rolling elements 15a and 15b, a seal ring 1a, and an axially inner seal ring 16.

  The outer ring 9 is made of medium carbon steel, and has a double row of outer ring raceways 17a and 17b provided on the inner peripheral surface, and a stationary side flange 18 provided in a state of projecting radially outward from the outer peripheral surface in the axial direction intermediate portion. And a thin-walled portion 12 provided on the entire outer periphery in the axial direction. The outer ring 9 is supported and fixed to the suspension device by bolts inserted or screwed into mounting holes 19 provided at a plurality of locations in the circumferential direction of the stationary flange 18.

  In this example, a groove 10 having a semicircular cross section that is recessed radially inward is provided on the outer circumferential surface of the outer side of the outer ring 9 in the axial direction. The thin portion 12 is configured by a portion existing on the inner diameter side of the concave groove 10, and has a smaller radial thickness than portions adjacent to both sides of the outer ring 9 in the axial direction. That is, in the axially outer side portion of the outer ring 9, the portion existing outside the thinned portion 12 in the axial direction is the thickened portion 11a on the axially outer side having a larger radial thickness than the thinned portion 12, A portion existing inside the thin portion 12 with respect to the axial direction is a thick portion 11 b on the inner side in the axial direction having a larger radial thickness than the thin portion 12. Further, the radial thickness of the thick portion 11a on the outer side in the axial direction is smaller from the thin portion 12 toward the outer side in the axial direction. More specifically, the inner peripheral surface of the thick portion 11a on the outer side in the axial direction is inclined in a direction in which the inner diameter increases as it goes outward in the axial direction. On the other hand, the inner peripheral surface of the thin portion 12 is a cylindrical surface having a constant inner diameter with respect to the axial direction.

  In addition, the cross-sectional shape of the concave groove 10 is not limited to the semicircular shape as illustrated, and a rectangular shape, a V shape, a U shape, or the like is also applicable.

  The hub 8 a is disposed coaxially with the outer ring 9 on the inner diameter side of the outer ring 9. Such a hub 8a includes double row inner ring raceways 20a and 20b provided at the axially intermediate portion of the outer peripheral surface, and a portion of the outer peripheral surface that protrudes axially outward from the axial outer end surface of the outer ring 9. And a rotation-side flange 21 provided so as to protrude outward in the radial direction. Through holes 22 are provided at a plurality of locations in the circumferential direction of the rotation side flange 21, and the base end portion of the stud 23 is press-fitted and fixed inside the through holes 22. In the state of use, a braking rotator such as a disk rotor and a drum brake and a wheel constituting the wheel are supported and fixed to the rotation side flange 21 of the hub 8 a by the stud 23.

  In this example, the hub 8 a is configured by combining the hub body 24 and the inner ring 25. The hub main body 24 is made of medium carbon steel, and an inner ring raceway 20a on the outer side in the axial direction of the double row inner ring raceways 20a and 20b is provided on the outer peripheral face in the axial direction. A rotation-side flange 21 is provided at a portion located on the outer side in the axial direction from the outer ring raceway 20a. A small-diameter step portion 26 having an outer diameter smaller than that of a portion adjacent to the outside in the axial direction is provided at the inner end portion in the axial direction of the hub body 24.

  In this example, a concave portion 27 having a rectangular cross section that is recessed outward in the axial direction is provided on the inner surface in the axial direction of the rotation side flange 21 over the entire circumference. By inserting the axially outer end of the outer ring 9 into such a recess 27, a cross-section that is a non-contact type seal between the rotation side flange 21 and the axially outer end of the outer ring 9. A labyrinth seal 28 having a U-shape is provided. The labyrinth seal 28 includes a radial labyrinth seal 29, an outer radial side labyrinth seal 30a, and an inner radial side labyrinth seal 30b. The radial labyrinth seal 29 is formed by causing the bottom surface (axial inner side surface) of the recess 27 and the axial outer end surface of the outer ring 9 to face each other close to each other. Further, the axial labyrinth seal 30a on the outer diameter side is configured so that the outer peripheral side peripheral surface of the inner surface of the recess 27 and the outer peripheral surface of the outer ring 9 in the axial direction are closely opposed to each other. It is formed in a state of being bent and extended inward in the axial direction from the radially outer end. Furthermore, the axial labyrinth seal 30b on the inner diameter side has a diameter of the radial labyrinth seal 29 by causing the inner peripheral surface of the inner surface of the concave portion 27 and the inner peripheral surface of the outer ring 9 to approach each other in close proximity. It is formed so as to bend and extend inward in the axial direction from the inner end in the direction.

  The inner ring 25 is made of bearing steel, and the inner ring raceway 20b on the inner side in the axial direction of the double row inner ring raceways 20a and 20b is provided on the outer peripheral surface. Such an inner ring 25 is externally fitted to the small-diameter step portion 26 of the hub body 24, and the inner end surface in the axial direction of the inner ring 25 is pressed by a caulking portion 38 provided at the inner end portion in the axial direction of the small-diameter step portion 26. The hub body 24 and the inner ring 25 are fixedly coupled.

  Each of the rolling elements 15a and 15b is made of bearing steel, and a plurality of rolling elements 15a and 15b are provided between the double-row outer ring raceways 17a and 17b and the double-row inner ring raceways 20a and 20b, respectively, so as to be freely rollable. In the illustrated example, the pitch circle diameter of the rolling elements 15a in the axially outer row is larger than the pitch circle diameter of the rolling elements 15b in the axially inner row, and the ball diameter of the rolling elements 15a in the axially outer row. Is made smaller than the ball diameter of the rolling elements 15b in the axially inner row. However, the ball diameter of the rolling elements 15a in the axially outer row may be the same as the ball diameter of the rolling elements 15b in the axially inner row, or may be larger than the ball diameter of the rolling elements 15b in the axially inner row. You can also. The pitch circle diameter of the rolling elements 15a in the axially outer row may be the same as the pitch circle diameter of the rolling elements 15b in the axially inner row, or may be larger than the pitch circle diameter of the rolling elements 15b in the axially inner row. It can also be made smaller. In the illustrated example, balls are used as the rolling elements 15a and 15b, but tapered rollers can also be used.

  The seal ring 1a is for closing the axially outer opening of the inner space 13 existing between the inner peripheral surface of the outer ring 9 and the outer peripheral surface of the hub 8a. The annular core metal 2a and the core metal 2a It is comprised from the sealing material 3a reinforced by this.

  The cored bar 2a is made by bending a metal plate such as a mild steel plate, and has a cylindrical fitting tube portion 4a and a radially inward portion from the axially outer end portion of the fitting tube portion 4a. And an annular inner ring portion 5a that is bent and extended. In addition, the axial direction inner end part of the fitting cylinder part 4a becomes a free end which is not couple | bonded with the other part of the metal core 2a. Further, the outer peripheral surface of the fitting cylinder portion 4a is a cylindrical surface having a constant outer diameter in the axial direction.

  The seal material 3 a is made of an elastomer such as rubber or other elastic material, and is vulcanized and bonded to the core metal 2 a and has three contact-type seal lips 7.

  The seal ring 1a having such a configuration has an inner diameter side of the axially outer side portion of the outer ring 9 by fitting the fitting cylindrical portion 4a of the core metal 2a to the inner peripheral surface of the outer side of the outer ring 9 with an interference fit. It is attached to. In this state, the seal lip 7 is slidably contacted with the inner peripheral surface of the axial direction inner surface of the rotation side flange 21 or the axial intermediate portion of the hub 8a over the entire circumference, so that the outer edge of the inner space 13 is axially outer. The opening is blocked. In the illustrated example, the number of the seal lips 7 is three, but the number of the contact-type seal lips 7 can be an arbitrary number of one or more. However, the number of the contact-type seal lips 7 is determined from the surface that prevents the sliding contact resistance between the tip edge of the seal lip 7 and the surface of the hub 8a from increasing unnecessarily while ensuring a good sealing effect. Two or three are preferable.

  In this example, with the seal ring 1a mounted on the inner diameter side of the axially outer side portion of the outer ring 9, the axially outer end portion of the fitting tube portion 4a is located outside the concave groove 10 in the axial direction. The inner end portion in the axial direction of the fitting tube portion 4a is positioned on the inner diameter side of the thin portion 12. That is, the outer peripheral surface in the axial direction outer end of the fitting tube portion 4a is fitted into the inner peripheral surface of the thick portion 11a on the outer side in the axial direction by an interference fit, and the outer peripheral surface in the axial direction inner end portion of the fitting tube portion 4a. However, it is made to fit in the inner peripheral surface of the thin part 12 by interference fit. Of the inner peripheral surface of the outer side portion of the outer ring 9 in the axial direction, the portion to which the fitting tube portion 4a is fitted is a cylindrical surface having a constant inner diameter in the axial direction.

  The axially inner seal ring 16 is a combined seal ring composed of a slinger and a seal ring, and closes the axially inner opening of the internal space 13. However, the axially inner opening of the outer ring 9 can be closed by a bottomed cylindrical cover fitted to the inner end of the outer ring 9 in the axial direction.

  In this example, a labyrinth seal 28 is provided between the rotation side flange 21 and the outer end of the outer ring 9 in the axial direction. For this reason, foreign matter such as rainwater and muddy water that adheres to the outer peripheral surface of the outer ring 9 and travels along the outer peripheral surface and reaches the outer peripheral surface of the outer end portion in the axial direction of the outer ring 9 is blocked by the labyrinth seal 28. . As a result, the foreign matter can hardly reach the sliding contact portion between the tip edge of the seal lip 7 and the surface of the hub 8a.

  In addition, since the outer circumferential surface of the outer ring 9 is provided with a concave groove 10 that is recessed inward in the radial direction, the foreign matter reaching the outer circumferential surface of the outer side of the outer ring 9 is recessed. It is guided to the road surface side by the groove 10 and is easily discharged to the outside. Also from this surface, the foreign matter can hardly reach the sliding contact portion between the tip edge of the seal lip 7 and the surface of the hub 8a.

  Furthermore, according to the wheel bearing rolling bearing unit 14 of this example, when the outer peripheral surface of the fitting cylinder portion 4a is press-fitted into the inner peripheral surface of the outer side of the outer ring 9 in the axial direction, the outer peripheral surface of the fitting cylinder portion 4a is applied. It is possible to prevent the press-fitting wound from being formed over the entire length in the axial direction. As a result, it is possible to sufficiently ensure the sealing performance of the fitting portion between the outer peripheral surface of the fitting cylinder portion 4a and the inner peripheral surface of the outer side of the outer ring 9 in the axial direction. This point will be described in more detail below.

  In this example, the inner diameter side annular portion 5a of the cored bar 2a is provided in a state of being bent radially inward from the axially outer end portion of the fitting tube portion 4a. For this reason, the rigidity in the radial direction of the fitting cylinder portion 4a is the largest at the outer end portion in the axial direction and decreases as it goes inward in the axial direction. When the fitting tube portion 4a of the metal core 2a is press-fitted into the axially outer side inner peripheral surface of the outer ring 9 in order to mount the seal ring 1a, first, the rigidity in the radial direction is set in the fitting tube portion 4a. The smallest axially inner end portion is press-fitted into the axially outer side inner peripheral surface of the outer ring 9. Therefore, the surface pressure between the outer peripheral surface of the fitting tube portion 4a and the inner peripheral surface of the outer side in the axial direction of the outer ring 9 at the initial stage of the press-fitting operation of the fitting tube portion 4a is compared with that in the conventional structure shown in FIG. And can be kept small. For this reason, in the initial stage of the press-fitting work of the fitting cylinder part 4a, it is difficult to form an initial press-fitting wound that is a source of scratches over the entire length in the axial direction on the outer peripheral surface of the axially inner end part of the fitting cylinder part 4a. it can.

  Further, the radial thickness of the portion of the outer ring 9 that is fitted to the axially inner end of the fitting tube portion 4a in the axially outer side portion is determined by the progress of the press-fitting operation of the fitting tube portion 4a (fitting tube portion). 4a is pushed toward the inner side in the axial direction with respect to the outer ring 9, the smaller the press-fitting amount of the fitting cylinder portion 4a, the smaller the rigidity in the radial direction. Therefore, as the press-fitting amount of the fitting cylinder portion 4a is increased, the surface pressure between the outer peripheral surface of the inner end portion in the axial direction of the fitting cylinder portion 4a and the inner peripheral surface of the outer side portion in the axial direction of the outer ring 9 decreases. In the state where the press-fitting operation of the fitting cylinder portion 4a is completed, the outer peripheral surface of the inner end portion in the axial direction of the fitting cylinder portion 4a is present inward in the radial direction of the concave groove 10 and is thin with a small rigidity in the radial direction. It fits with the inner peripheral surface of the part 12. Therefore, even if a press-fitting flaw is formed on the outer peripheral surface of the inner end of the fitting cylinder part 4a in the initial stage of the press-fitting work of the fitting cylinder part 4a, Is difficult to grow. As a result, this press-fitting flaw can be prevented from being formed over the entire length in the axial direction on the outer peripheral surface of the fitting cylinder portion 4a.

  Further, the axially outer end portion having the greatest radial rigidity in the fitting cylinder portion 4a is the thin portion 12 having the radial rigidity in the outer ring 9 at the final stage of the press-fitting operation of the fitting cylinder portion 4a. It is press-fitted into the inner peripheral surface of the thicker portion 11a on the outer side in the larger axial direction. Therefore, when the fitting tube portion 4a is press-fitted, the sliding between the outer peripheral surface of the axial outer end portion having the greatest radial rigidity in the fitting tube portion 4a and the inner peripheral surface of the outer side portion of the outer ring 9 in the axial direction. The contact length can be shortened. As a result, it is possible to prevent press-fitting from being formed on the outer peripheral surface of the outer end portion in the axial direction of the fitting tube portion 4a, or even if it is formed, it can be suppressed to a small size. Accordingly, it is possible to sufficiently secure an area in which the outer peripheral surface of the outer end portion in the axial direction of the fitting cylinder portion 4a and the inner peripheral surface of the thick portion 11a on the outer side in the axial direction are fitted (contacted). As a result, it is possible to sufficiently secure the fitting force of the outer peripheral surface in the axial outer end portion of the fitting cylinder portion 4 a with respect to the inner peripheral surface of the outer side portion of the outer ring 9.

  As described above, according to the structure of this example, it is possible to prevent the press-fitting from being formed on the outer peripheral surface of the fitting tube portion 4a in the axial direction, and to fit the outer ring 9 to the inner peripheral surface in the axial outer side portion. It is possible to sufficiently secure the fitting force on the outer peripheral surface of the outer end portion in the axial direction of the cylindrical portion 4a. Therefore, it is possible to sufficiently ensure the sealing performance of the fitting portion between the outer peripheral surface of the fitting cylinder portion 4a and the inner peripheral surface of the outer side of the outer ring 9 in the axial direction. As a result, foreign matter such as rainwater and muddy water travels along the surface of the outer ring 9 and reaches the outer end in the axial direction of the fitting portion between the outer peripheral surface of the fitting tube portion 4a and the inner peripheral surface of the outer side of the outer ring 9 in the axial direction. Even if it does, it can prevent more reliably that a foreign material permeates in the internal space 13 through a press-fitting wound.

  Furthermore, in this example, in the inner peripheral surface of the outer ring 9, the portion between the outer end in the axial direction and the portion where the fitting tube portion 4a is fitted (in the axial direction than the thick portion 11a on the outer side in the axial direction). The outer portion is an inclined surface having a larger diameter toward the outer side in the axial direction. Therefore, before the fitting cylinder portion 4a starts to be press-fitted into the inner peripheral surface of the outer side in the axial direction of the outer ring 9, it is possible to prevent the fitting cylinder portion 4a from sliding strongly against the inner peripheral surface of the outer ring 9, and It is possible to prevent press-fitting from being formed on the outer peripheral surface of the portion 4a.

  In this example, the case where the present invention is applied to a wheel bearing rolling bearing unit for a driven wheel having a solid hub 8a has been described. However, the present invention may also be applied to a wheel support rolling bearing unit for a drive wheel in which an engagement hole such as a spline hole for engaging the power of the drive shaft in a central portion of the hub is provided. it can.

[Second Example of Embodiment]
FIG. 3 shows a second example of the embodiment of the present invention. In this example, the outer end surface in the axial direction of the outer ring 9a is an inclined surface that is inclined in a direction toward the outer side in the axial direction toward the outer side in the radial direction. Further, a concave portion 27a having a substantially right-angled triangular cross section is provided over the entire circumference on the inner side surface in the axial direction of the rotation side flange 21a. The bottom surface (axial inner side surface) of the recess 27a is an inclined surface parallel to the axial outer end surface of the outer ring 9a.

  A non-contact type labyrinth seal 28a is provided between the rotation side flange 21a and the outer end portion in the axial direction of the outer ring 9a by inserting the outer end portion in the axial direction of the outer ring 9a into the recess 27a. ing. The labyrinth seal 28a includes a radial labyrinth seal 29a and an axial labyrinth seal 30c. The radial labyrinth seal 29a is formed by causing the bottom surface of the recess 27a, which are inclined surfaces parallel to each other, and the axially outer end surface of the outer ring 9a to face each other close to each other. Further, the axial labyrinth seal 30c is formed so that the outer peripheral side surface of the concave portion 27a and the outer peripheral surface of the outer ring 9a are close to each other so that the axial labyrinth seal 30c extends from the radial outer end of the radial labyrinth seal 29a. It is formed so as to bend inward and extend.

In this example, the axial length of the axial labyrinth seal 30c is easier to ensure than the axial length of the axial radial labyrinth seal 30a constituting the labyrinth seal 28 of the first example of the embodiment. For this reason, it is easy to improve the labyrinth effect by the labyrinth seal 28a as compared with the labyrinth seal 28 of the first example of the embodiment.
The structure and operation of other parts are the same as in the first example of the embodiment.

[Third example of embodiment]
FIG. 4 shows a third example of the embodiment of the present invention. In this example, an inclined surface portion 31 is provided on the inner circumferential surface of the outer end portion 9b of the outer ring 9b so as to be inclined in the radially outward direction as it goes outward in the axial direction. In the illustrated example, the inclined surface portion 31 is provided in a portion from the axial outer end edge of the inner peripheral surface of the outer ring 9 b to the axial intermediate portion of the inner peripheral surface of the thin portion 12. The concave groove 10 is provided in a portion adjacent to the axial outer end of the outer circumferential surface of the outer ring 9b in the axial direction, and the thick outer portion 11a on the outer side in the axial direction is the outer end in the axial direction of the outer ring 9b. Part.

  The cored bar 2b constituting the seal ring 1b includes a cylindrical fitting tube portion 4b and a ring-shaped inner diameter side circle that extends and bends radially inward from the axially inner end of the fitting tube portion 4b. And an annular portion 5b. In addition, the axial direction outer end part of the fitting cylinder part 4b becomes a free end which is not couple | bonded with the other part of the metal core 2b. Therefore, the rigidity in the radial direction of the fitting cylinder portion 4b is greatest at the inner end portion in the axial direction and decreases toward the outer side in the axial direction.

  In the state where the seal ring 1b is mounted on the inner diameter side of the outer side portion of the outer ring 9b in the axial direction, the inner end portion in the axial direction of the fitting tube portion 4b is provided on the outer peripheral surface of the outer side portion of the outer ring 9b in the axial direction. It is made to be located inside the concave groove 10. That is, in this example, the outer peripheral surface of the outer end portion in the axial direction of the fitting cylinder portion 4b is fitted into the inner peripheral surface of the thin portion 12 with an interference fit. On the other hand, the outer peripheral surface of the inner end portion in the axial direction of the fitting tube portion 4b is an inner shaft of the outer ring 9b that is present on the inner side of the groove 10 in the axial direction and has a larger radial thickness than the thin portion 12. It is fitted by interference fit on the inner peripheral surface of the thick portion 11b on the inner side in the direction.

  In this example, the outer end surface in the axial direction of the outer ring 9b is an inclined surface that is inclined in the direction toward the inner side in the axial direction as it goes outward in the radial direction. Further, a concave portion 27b that is recessed outward in the axial direction is provided on the inner surface in the axial direction of the rotation-side flange 21b, and the bottom surface (axial inner surface) of the concave portion 27b is connected to the outer end surface in the axial direction of the outer ring 9b. Parallel inclined surfaces.

  A non-contact type labyrinth seal 28b is provided between the rotation side flange 21b and the outer end portion in the axial direction of the outer ring 9b by inserting the outer end portion in the axial direction of the outer ring 9b into the recess 27b. . The labyrinth seal 28b includes a radial labyrinth seal 29b, an axial labyrinth seal 30d on the outer diameter side, and an axial labyrinth seal 30e on the inner diameter side. The radial labyrinth seal 29b is an axially inward direction as it goes radially outward by making the bottom surface of the recess 27b and the axially outer end surface of the outer ring 9b approach each other, which are inclined surfaces parallel to each other. It is formed in a state of extending. Further, the axial labyrinth seal 30d on the outer diameter side is configured so that the outer peripheral side peripheral surface of the recess 27b and the outer peripheral surface of the outer ring 9b in the axial direction are closely opposed to each other, so It is formed so as to bend and extend inward in the axial direction from the end. Further, the axial labyrinth seal 30e on the inner diameter side has a radially inner end portion of the radial labyrinth seal 29b by causing the inner peripheral surface of the concave portion 27b and the inner peripheral surface of the outer ring 9b to face each other close to each other. It is formed so as to bend and extend inward in the axial direction.

  Also in the case of this example, when the fitting cylinder part 4b of the core metal 2b is press-fitted into the inner peripheral surface of the outer side in the axial direction of the outer ring 9b in order to attach the seal ring 1b, the fitting cylinder part 4b It can prevent that it forms in the outer peripheral surface of the whole axial direction.

  In this example, an inclined surface portion 31 is provided on the inner circumferential surface of the outer end portion 9b of the outer ring 9b so as to be inclined in the radially outward direction as it goes outward in the axial direction. For this reason, in the initial stage of the press-fitting operation of the fitting cylinder part 4b, the outer peripheral surface of the inner end part in the axial direction of the fitting cylinder part 4b is thicker on the outer side in the axial direction having a large radial rigidity in the outer ring 9b. It does not fit with the inner peripheral surface of 11a. When the fitting tube portion 4b is press-fitted into the inner peripheral surface of the outer side portion 9b in the axial direction, the inner end portion in the axial direction of the fitting tube portion 4b is first press-fitted into the inner peripheral surface of the thin portion 12 of the outer ring 9b. The Since the rigidity in the radial direction of the thin wall portion 12 is relatively small, the surface pressure between the outer peripheral surface of the fitting tube portion 4b and the inner peripheral surface of the outer portion 9b in the axial direction at the initial stage of the press-fitting operation of the fitting tube portion 4b. Can be kept relatively small. As a result, at the initial stage of the press-fitting operation of the fitting tube portion 4b, an initial press-fitting scratch that is a source of scratches over the entire length in the axial direction is hardly formed on the outer peripheral surface of the fitting tube portion 4b in the axial direction. it can.

  The axially inner end portion having the greatest radial rigidity in the fitting cylinder portion 4b is located inward of the outer ring 9b with respect to the axial direction in the axial direction in the outer ring 9b. It is press-fitted into the inner peripheral surface of the thick portion 11b that is positioned and has a larger radial thickness than the thin portion 12 in the axial direction. Therefore, the sliding contact length between the axially inner end portion having the greatest radial rigidity in the fitting cylinder portion 4b and the portion having the large radial rigidity in the outer ring 9b can be shortened. As a result, it is possible to prevent the press-fitting from being formed on the outer peripheral surface of the inner end portion in the axial direction of the fitting tube portion 4b, or even if it is formed, it can be suppressed to a small size. Therefore, the axial direction in which the rigidity in the radial direction is larger than that in the thin portion 12 in the outer peripheral surface of the axially inner end portion of the fitting cylindrical portion 4b and the axially outer end portion of the outer ring 9b. A sufficient area with the inner peripheral surface of the inner thick portion 11b can be secured. As a result, it is possible to sufficiently secure the fitting force of the outer circumferential surface of the inner end portion in the axial direction of the fitting cylinder portion 4b with respect to the inner circumferential surface of the outer side portion of the outer ring 9b.

  As described above, according to the structure of this example, it is possible to prevent the press-fitting from being formed on the outer peripheral surface of the fitting tube portion 4b in the axial direction, and to fit the outer ring 9b to the inner peripheral surface in the axial outer side portion. A sufficient fitting force on the outer peripheral surface of the inner end portion in the axial direction of the cylindrical portion 4b can be ensured. Therefore, it is possible to sufficiently ensure the sealing performance of the fitting portion between the outer peripheral surface of the fitting cylinder portion 4b and the inner peripheral surface of the outer side portion 9b in the axial direction.

In this example, the radial labyrinth seal 29b constituting the labyrinth seal 28b is provided so as to extend in the axially inward direction as it goes radially outward. For this reason, even when the moment force based on the road surface reaction force is applied to the rotation side flange 21b while the vehicle is traveling, the width dimension of the radial labyrinth seal 29b even when the center axis of the hub 8b is inclined with respect to the center axis of the outer ring 9b. Can be made substantially constant in the length direction. Therefore, it is easy to set the width dimension of the radial labyrinth seal 29b to be small, and it is easy to improve the labyrinth effect.
The structure and operation of other parts are the same as in the first example of the embodiment.

[Fourth Example of Embodiment]
FIG. 5 shows a fourth example of the embodiment of the present invention. In this example, as in the third example of the embodiment, the inclined surface portion 31 that is inclined in the radially outward direction as it goes outward in the axial direction is provided on the inner peripheral surface of the outer end 9c in the axial direction. ing. The inclined surface portion 31 is provided in a portion extending from an axial outer end edge of the inner peripheral surface of the outer ring 9c to an axial intermediate portion of the inner peripheral surface of the thin portion 12 of the outer ring 9c.

  The cored bar 2c constituting the seal ring 1c includes a cylindrical fitting tube portion 4c and a ring-shaped inner diameter side circle that extends and bends radially inward from the axially inner end of the fitting tube portion 4c. An annular portion 5c and an annular outer diameter side annular portion 32 that is bent and extended radially outward from the axially outer end portion of the fitting cylinder portion 4c are provided.

  In this example, the inner surface in the axial direction of the outer diameter side annular portion 32 is abutted against the outer end surface in the axial direction of the outer ring 9c through a part of the sealing material 3b. Moreover, the dam part 33 is provided by covering the part which protruded in the radial direction outer side from the axial direction outer end surface outer periphery of the outer ring | wheel 9c among the outer diameter side annular ring parts 32 with the sealing material 3b.

  Further, a labyrinth slip 34 is provided in a portion of the plurality of seal lips 7 positioned further radially outward than the seal lip 7 provided on the outermost radial direction. An axially outer half portion of the labyrinth slip 34 and a stepped portion 35 provided in a radially outward direction at the radially intermediate portion of the rotation side flange 21 are overlapped in the radial direction. And the axial labyrinth seal 36 is provided in the said part by making the axial direction outer half part internal peripheral surface of the labyrin slip 34 and the step part 35 adjoin and oppose. Further, the portion of the sealing material 3b that covers the axially outer side surface of the outer-diameter-side annular portion 32 and the axially inner side surface of the radially inner half portion of the rotation-side flange 21 are closely opposed to each other, thereby causing the radial direction. A labyrinth seal 37 is provided.

  According to this example, the outer diameter side annular portion 32 constituting the cored bar 2c is abutted against the axially outer end surface of the outer ring 9c via a part of the sealing material 3b. The positioning in the axial direction can be facilitated.

  The seal ring 1c is provided with a weir 33 that protrudes radially outward from the outer peripheral edge of the outer ring 9c in the axial direction. For this reason, even when foreign matter such as rainwater or muddy water adhering to the outer peripheral surface of the outer ring 9 c reaches the outer peripheral surface of the outer end of the outer ring 9 c in the axial direction beyond the concave groove 10, the foreign matter is dammed by the dam portion 33. Stopping and reaching the outer peripheral surface of the labyrinth slip 34 can be prevented. A part of the sealing material 3b is interposed between the axial inner side surface of the outer diameter side annular portion 32 of the core metal 2c and the axial outer end surface of the outer ring 9c. Therefore, the foreign matter reaching the outer peripheral surface of the outer ring 9c in the axial direction is less likely to enter the inner diameter side between the axial inner surface of the outer ring side annular portion 32 and the outer outer surface of the outer ring 9c in the axial direction. it can.

In this example, the labyrinth slip 34 is provided on the sealing material 3 b, whereby the axial labyrinth seal 36 is provided between the inner peripheral surface of the labyrinth slip 34 and the stepped portion 35. Further, a radial labyrinth seal is provided between a portion of the sealing material 3 b that covers the axially outer side surface of the outer diameter side annular portion 32 and the axially inner side surface of the radially inner half of the rotation side flange 21. 37 is provided. Therefore, even when the hub 8a is inclined with respect to the outer ring 9c, it is difficult to generate metal contact between the hub 8a and the outer ring 9c.
Other configurations and operations are the same as those of the first and third examples of the embodiment.

DESCRIPTION OF SYMBOLS 1, 1a-1c Seal ring 2, 2a-2c Core metal 3, 3a, 3b Sealing material 4, 4a-4c Fitting cylinder part 5, 5a-5c Inner diameter side annular part 6 Outer diameter side annular part 7 Seal lip 8, 8a, 8b Hub 9, 9a-9c Outer ring 10 Recessed groove 11, 11a, 11b Thick part 12 Thin part 13 Inner space 14 Rolling bearing unit for wheel support 15a, 15b Rolling element 16 Seal ring 17a, 17b Outer ring raceway 18 Stationary side flange 19 Mounting hole 20a, 20b Inner ring raceway 21, 21a, 21b Rotating side flange 22 Through hole 23 Stud 24 Hub body 25 Inner ring 26 Small diameter step 27, 27a, 27b Recess 28, 28a, 28b Labyrinth seals 29, 29a, 29b Radial direction labyrinth seal 30a-30e Axial labyrinth seal 31 Inclined surface part 32 Outer diameter side ring 33 weir 34 the labyrinth lip 35 step portion 36 axially labyrinth seal 37 radially labyrinth seal 38 crimped portion

Claims (4)

An outer ring having an outer ring raceway provided on the inner peripheral surface, and a thin wall part provided on the entire outer periphery in the axial direction and having a smaller radial thickness than a part adjacent to the outer side in the axial direction;
A hub having an inner ring raceway provided on the outer peripheral surface;
A plurality of rolling elements provided in a freely rollable manner between the outer ring raceway and the inner ring raceway;
A seal ring that closes the axially outer opening of the internal space existing between the inner peripheral surface of the outer ring and the outer peripheral surface of the hub;
The seal ring is composed of an annular cored bar and a sealing material made of an elastic material reinforced by the cored bar,
A fitting tube portion in which the core metal is fitted on the inner peripheral surface of the outer side in the axial direction of the outer ring; and an inner diameter side annular portion bent inward in the radial direction from the axial outer end portion of the fitting tube portion; Have
The axially outer end portion of the fitting tube portion is located outside the thin portion with respect to the axial direction, and the axially inner end portion of the fitting tube portion is located on the inner diameter side of the thin portion. A rolling bearing unit for wheel support. An outer ring having an outer ring raceway provided on the inner peripheral surface, and a thin part that is provided over the entire circumference on the outer side in the axial direction and has a smaller radial thickness than a part adjacent to the inner side in the axial direction;
A hub having an inner ring raceway provided on the outer peripheral surface;
A plurality of rolling elements provided in a freely rollable manner between the outer ring raceway and the inner ring raceway;
A seal ring that closes the axially outer opening of the internal space existing between the inner peripheral surface of the outer ring and the outer peripheral surface of the hub;
The seal ring is composed of an annular cored bar and a sealing material made of an elastic material reinforced by the cored bar,
A fitting tube portion in which the core metal is fitted on the inner circumferential surface of the outer side in the axial direction of the outer ring; and an inner diameter side annular portion bent inward in the radial direction from the axial inner end portion of the fitting tube portion; Have
The axially inner end portion of the fitting tube portion is located on the inner side of the thin portion with respect to the axial direction,
A wheel bearing rolling bearing unit in which an inner diameter of an outer end portion in the axial direction of the outer ring existing outside the thin portion in the axial direction is larger than an inner diameter of the thin portion. The inner peripheral surface of the outer end portion in the axial direction of the outer ring that exists outside the thin portion with respect to the axial direction is inclined in a direction in which the inner diameter increases toward the outer side in the axial direction.
The rolling bearing unit for wheel support according to claim 2. On the outer circumferential surface of the outer side in the axial direction of the outer ring, a groove that is recessed radially inward is provided in the circumferential direction,
The thin portion is configured by a portion existing on the inner diameter side of the concave groove in the outer side in the axial direction of the outer ring.
The rolling bearing unit for wheel support according to any one of claims 1 to 3.

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