JP2018096417A - Wheel support rolling bearing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a structure which can reduce an amount of a water component such as rainwater and muddy water flowing inside a radial direction along an axial inside face of a rotation-side flange reaching a contact lip through a clearance existing between the inside face of the rotation-side flange and a tip of a non-contact lip when the rotation of a hub is stopped.SOLUTION: A non-contact lip 37 is inclined to a direction progressing toward the outside of a radial direction as progressing toward a tip being an axial outer end part from a base end part being an axial inside end part, and a tip of the non-contact lip 37 is made to approximate an outer end part of an inside-diameter side step part 18 which is formed at an axial inside face of a rotation-side flange 11 over the whole periphery. In this state, an axial outer end edge P of an external peripheral face of the non-contact lip 37 is located inside the radial direction rather than a radial inner end edge of an outside-diameter side step part 17 which is formed at the axial inside face of the rotation-side flange 11.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a wheel-supporting rolling bearing unit used for rotatably supporting a vehicle wheel with respect to a suspension device.

  2. Description of the Related Art A wheel bearing rolling bearing unit is used as a rolling bearing device for rotatably supporting a vehicle wheel with respect to a suspension device. As such a wheel-supporting rolling bearing unit, Patent Document 1 discloses that the inner peripheral surface of an outer ring that does not rotate even when used while being supported and fixed to a suspension device, and the wheel rotates while being supported and fixed. A structure is described in which an axially outer end opening of an internal space (rolling element installation space) provided between the outer peripheral surface of the hub is closed with a seal ring.

  In the entire specification and claims, “outside” in the axial direction means the left side of FIGS. On the contrary, the right side of FIGS. 1, 2, 4, 5, and 6 which is the center side in the width direction of the vehicle body is referred to as “inside” in the axial direction.

  The seal ring is supported and fixed to the outer end of the outer ring in the axial direction, and is provided on the outer surface in the radial direction with respect to the contact lip that is in sliding contact with the entire surface of the hub. And a non-contact lip having a front end portion that is close to and opposed to the inner surface in the axial direction of the rotation side flange provided at the outer end portion in the axial direction of the hub.

  In the seal ring of the conventional structure having the above-described configuration, the labyrinth seal is formed at the close-facing portion by making the tip of the non-contact lip approach the axial inner surface of the rotating flange. Therefore, the amount of water (foreign matter) such as rain water and muddy water splashed from the road surface reaching the contact lip can be reduced.

JP 2014-169724 A

  However, in the case of the above-described conventional structure, for example, when the automobile stops while the automobile is traveling on a wet road surface and moisture is attached to the inner side surface in the axial direction of the rotation side flange, Possibility of reaching the contact lip through a gap existing between the axial inner surface of the rotating side flange and the tip of the non-contact lip, flowing radially inward along the axial inner surface of the flange There is.

  If moisture reaches the contact lip in this way, the durability of the contact lip may be adversely affected. For this reason, it is desired to realize a structure capable of suppressing the amount of moisture reaching the contact lip as described above.

  In the present invention, in view of the above-described circumstances, when rotation of the hub is stopped, moisture such as rain water and muddy water flowing inward in the radial direction along the axial inner surface of the rotation side flange causes the rotation side flange to The invention has been invented to realize a structure that can suppress the amount reaching the contact lip through a gap existing between the inner surface in the axial direction and the tip of the non-contact lip.

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.
Of these, the outer ring has an outer ring raceway on the inner peripheral surface, and does not rotate while being supported and fixed to the suspension device during use.
The hub has an inner ring raceway in a portion of the outer peripheral surface facing the outer ring raceway, and is used for supporting and fixing a wheel on a portion of the outer peripheral surface located axially outside the outer ring. It has a rotation side flange.
The plurality of rolling elements are provided between the outer ring raceway and the inner ring raceway so as to roll freely.
Further, the seal ring is supported and fixed at the axially outer end portion of the outer ring, and has an axially outer end opening in an inner space existing between the inner peripheral surface of the outer ring and the outer peripheral surface of the hub. It is blocking.
The rotation-side flange includes a recess provided in a state of being recessed in the axial direction at a plurality of positions in the circumferential direction from the radial intermediate portion of the inner surface in the axial direction to the outer end portion, and the diameter of the inner surface of each of the recesses. And a step portion which is provided at each inner end portion in the direction and is inclined in a curve or linearly in a direction toward the inner side in the axial direction toward the inner side in the radial direction.
The seal ring includes a contact lip made of an elastic material and a non-contact lip made of an elastic material provided on the outer side in the radial direction from the contact lip.
The tip of the contact lip is in sliding contact with the mating surface rotating relative to the outer ring over the entire circumference.
Further, the non-contact lip is inclined in a direction toward the radially outer side from the base end portion which is the inner end portion in the axial direction toward the front end portion which is the outer end portion in the axial direction. The axially outer edge of the outer peripheral surface is close to and opposed to the portion adjacent to the inner side in the radial direction with respect to the radial position where each step portion exists in the axial inner surface of the side flange. However, it is arrange | positioned in the same radial direction position as the radial direction inner end edge of each said step part, or the radial direction position inside the radial direction inner end edge of each said step part.

  When carrying out the present invention, for example, in the virtual plane including the central axis of the hub and passing through the stepped portion, the axial outer edge of the outer peripheral surface of the non-contact lip is the diameter of the stepped portion. It is possible to adopt a configuration in which a tangential line at the inner edge in the direction or an extension line of the step portion passes, or a radial position inside the tangent line or the extension line.

  In carrying out the present invention, for example, a shaft portion and an axially intermediate portion fixed to the axially inner end portion of the shaft portion and having a larger outer diameter than the shaft portion and an axially intermediate portion of the outer peripheral surface. It is possible to employ a configuration further including a stud bolt having a head portion having a maximum diameter portion having a diameter dimension larger than that of other portions positioned on both sides in the axial direction. And the said rotation side flange has the insertion hole provided in the state pinched between the said recessed parts adjacent to each other regarding the circumferential direction in the state which penetrates the said part to an axial direction, In the stud bolt, the shaft portion is inserted into the insertion hole, and the axially outer side surface of the head is in contact with the axially inner side surface of the rotation side flange. It is possible to adopt a configuration in which the maximum diameter portion overlaps the outer peripheral surface of the non-contact lip in the radial direction.

  According to the rolling bearing unit for supporting a wheel of the present invention having the above-described configuration, when the hub stops rotating, rainwater, muddy water, and the like that flow radially inward along the axial inner surface of the rotation-side flange. The amount of water reaching the contact lip through the gap existing between the axially inner side surface of the rotation side flange and the tip of the non-contact lip can be reduced.

Sectional drawing of the rolling bearing unit for wheel support regarding the 1st example of embodiment of this invention. Similarly, the A section enlarged view of FIG. Similarly, the figure which took out only the hub main part and looked at the upper part of FIG. 1 from the axial direction inner side. Similarly, the elements on larger scale of Drawing 1 shown in the state where the stud bolt fixed to the rotation side flange was located in the upper part. The figure similar to the upper part of FIG. 2 regarding the modification of the 1st example of embodiment of this invention. The figure similar to FIG. 4 regarding the 2nd example of embodiment of this invention. Similarly, B arrow view of FIG.

[First example of embodiment]
A first example of the embodiment of the present invention will be described with reference to FIGS.
The wheel support rolling bearing unit of this example is for a driven wheel, and includes an outer ring 1, a hub 2, a plurality of rolling elements 3 and 3, a plurality of stud bolts 4, a seal ring 5, and a cap 6. With.

  The outer ring 1 has a stationary flange 7 on the outer peripheral surface, and double-row outer ring raceways 8a and 8b on the inner peripheral surface. Such an outer ring 1 does not rotate in a state where it is supported by the suspension device by connecting and fixing the stationary flange 7 to the knuckle of the suspension device in use.

  The hub 2 is configured by connecting a hub body 9 and an inner ring 10, and is arranged coaxially (concentrically) with the outer ring 1 on the inner diameter side of the outer ring 1.

  A circle for supporting and fixing a rotating member for braking such as a wheel (driven wheel) and a disk rotor on a portion of the outer peripheral surface of the hub main body 9 that protrudes outward in the axial direction from the axial outer end opening of the outer ring 1. An annular rotating flange 11 is provided. Further, an inner ring raceway 12 a in the axially outer row is provided in a portion of the outer circumferential surface of the hub body 9 that is opposed to the outer ring raceway 8 a in the axially outer row provided on the inner circumferential surface of the outer ring 1. Further, a small-diameter step portion 13 is provided at the inner end portion in the axial direction facing the outer ring raceway 8 b in the inner row in the axial direction provided on the inner peripheral surface of the outer ring 1 in the outer peripheral surface of the hub body 9.

  The outer surface in the axial direction of the rotation side flange 11 is a plane (annular surface) orthogonal to the central axis of the hub body 9 almost entirely except for the corner R portion provided at the inner end edge portion in the radial direction. It has become.

  On the other hand, on the inner side surface in the axial direction of the rotation-side flange 11, concave portions 14 and 14 are provided in a state of being recessed in the axial direction at a plurality of locations in the circumferential direction from the radial intermediate portion to the outer end portion. More specifically, each of these recesses 14 and 14 is provided in a state of opening in two directions, that is, the inner side in the axial direction and the outer side in the radial direction. In the case of this example, the portions that are aligned with the concave portions 14 and 14 in the circumferential direction in the radial direction intermediate portion to the outer end portion of the rotation side flange 11 are the thin portions 15. Further, in the radial direction intermediate portion or outer end portion of the rotation-side flange 11, the portions removed from the concave portions 14, 14 in the circumferential direction are thicker (the axial thickness dimension is larger than that of the thin portion 15). It is part 16.

  In addition, the radially inner end of the inner surface of each of the recesses 14 and 14 has a concave sectional shape cut by a virtual plane including the central axis of the hub body 9 that is inclined inward in the axial direction as it goes radially inward. An arc-shaped outer diameter side step portion 17 is formed. In the case of this example, each of the outer diameter side step portions 17 and 17 corresponds to the step portion described in the claims.

  Further, on the inner side surface in the axial direction of the rotation-side flange 11, at a position adjacent to the inner side in the radial direction with respect to the radial range in which the concave portions 14 and 14 are provided, the inner side in the radial direction is directed toward the inner side in the axial direction. An inner diameter side step portion 18 that is inclined in the direction and has a straight busbar shape is provided over the entire circumference. An annular surface portion 19 that is orthogonal to the central axis of the hub body 9 is provided over the entire circumference at a portion adjacent to the inner side in the axial direction of the inner diameter side step portion 18. Further, a portion adjacent to the inner side in the radial direction of the ring surface portion 19 is inclined in a direction toward the inner side in the axial direction toward the inner side in the radial direction. Is provided all around. In addition, a portion of the outer peripheral surface of the hub body 9 adjacent to the inner side in the axial direction of the curved surface portion 20 (a portion between the curved surface portion 20 and the inner ring raceway 12a in the axially outer row) has a diameter in the axial direction. A cylindrical surface portion 21 whose dimensions do not change is provided.

  Further, in the rotation side flange 11, a portion corresponding to each thick portion 16, which is a portion between the recesses 14 adjacent to each other in the circumferential direction, is inserted through the insertion hole 22 in a state of penetrating in the axial direction. Is provided.

  On the outer circumferential surface of the inner ring 10, an inner ring raceway 12 b in an axially inner row is provided. Such an inner ring 10 is held in the small-diameter step portion 13 of the hub main body 9 by an interference fit, and the inner end surface in the axial direction is suppressed by the caulking portion 23 formed at the inner end portion in the axial direction of the hub main body 9. It is attached.

  A plurality of rolling elements 3, 3 are respectively held in a portion between the outer ring raceway 8a and the inner ring raceway 12a in the outer row in the axial direction and a portion between the outer ring raceway 8b and the inner ring raceway 12b in the inner row in the axial direction. It is provided so that it can roll while being held by the vessels 24 and 24. In the illustrated example, balls are used as the rolling elements 3 and 3. However, in the case of a rolling bearing unit for supporting a wheel of an automobile that is heavy, tapered rollers may be used instead of the balls.

  The plurality of stud bolts 4 are used for supporting and fixing the wheel and the brake rotating member with respect to the rotation-side flange 11, and each of the stud bolts 4 includes a shaft portion 25 having a male screw portion formed on the outer peripheral surface thereof. The head portion 26 is fixed to the inner end portion in the axial direction of the shaft portion 25 and has a larger diameter dimension on the outer peripheral surface than the shaft portion 25. In the case of this example, the outer peripheral surface of the head 26 is a convex curved surface having a maximum diameter portion 27 having the largest diameter dimension at the axial center and having an arcuate generatrix. The plurality of stud bolts 4 having such a configuration are serrated and fitted (inserted) into the respective insertion holes 22 provided in the rotation side flange 11 by press-fitting the axially inner end portion of the shaft portion 25, The axially outer side surface of the head 26 is supported and fixed to the rotating side flange 11 with the axially inner side surface of each thick portion 16 provided on the rotating side flange 11 in contact.

The seal ring 5 includes a plurality of rolling elements 3 and 3 existing between the inner peripheral surface of the outer ring 1 and the outer peripheral surface of the hub 2 in a state where the seal ring 5 is supported and fixed to the outer end portion in the axial direction of the outer ring 1. The axially outer end opening of the provided internal space 28 is closed.
On the other hand, the cap 6 has a bottomed cylindrical shape, and closes the axially inner end opening of the outer ring 1 in a state where the cap 6 is assembled to the axially inner end of the outer ring 1.

  In the case of this example, the seal ring 5 is composed of a core metal 29 and a seal material 30.

  Of these, the core metal 29 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 tube portion 31 and a fitting tube portion. An outward flange 32 bent radially outward from the axially outer end of 31, and folded outwardly in the axial direction from the axially inner end of the fitting tube part 31 and directed radially inward And an inner diameter support portion 33 that is bent. Of these, the fitting tube portion 31 is fitted and fixed to the inner peripheral surface of the outer end portion of the outer ring 1 by an interference fit, and the inner side surface in the axial direction of the outer flange portion 32 is connected to the outer end surface in the axial direction of the outer ring 1. In this state, a part of the sealing material 30 is interposed. In the case of this example, the outer diameter of the outward flange 32 is larger than the outer diameter of the outer end of the outer ring 1 in the axial direction.

  The seal material 30 is made of an elastic material such as an elastomer such as rubber, and is fixedly coupled to the core metal 29. The three contact lips (contact seal lips) 34, 35, and 36, and one non-contact lip. (Non-contact type seal lip) 37.

  The three contact lips 34, 35, 36 are arranged in the order of the first contact lip 34, the second contact lip 35, and the third contact lip 36 from the side close to the internal space 28. The surface of the hub body 9, which is a mating surface that rotates relative to the outer ring 1, is in sliding contact with the entire circumference. More specifically, the tip of the first contact lip 34 is the cylindrical surface portion 21, the tip of the second contact lip 35 is the curved surface portion 20, and the tip of the third contact lip 36 is the ring surface portion 19, respectively. It is in sliding contact with the entire circumference. 1, 2, and 4, the shape of the sealing material 30 including the three contact lips 34, 35, and 36 is shown in a free state of the sealing material 30.

  Further, the first contact lip 34 is inclined in the direction toward the inner space 28 as it goes from the outer diameter side end portion as the base end portion toward the inner diameter side end portion as the distal end portion. Thereby, the function of preventing leakage of grease from the internal space 28 by the first contact lip 34 is enhanced. In addition, the second contact lip 35 and the third contact lip 36 are inclined in a direction toward the external space (away from the internal space 28) as they go from the base end to the tip. Thereby, the foreign matter intrusion prevention function from the external space by the second contact lip 35 and the third contact lip 36 is enhanced.

  On the other hand, the single non-contact lip 37 is provided on the radially outer side than the third contact lip 36, and the distance from the proximal end that is the axial inner end toward the distal end that is the axial outer end is increased. It is configured in the shape of a partial conical cylinder inclined in the direction toward the radially outer side. Such a non-contact lip 37 has a tip end portion on the radially outer end of the inner diameter side step portion 18 provided on the inner surface in the axial direction of the rotation side flange 11 (of the inner surface in the axial direction of the rotation side flange 11). Then, a labyrinth seal is formed on the portion that is close to and opposed to the portion that is adjacent to the outer diameter side stepped portions 17 and 17 over the entire circumference. Yes.

  In this example, as shown in FIGS. 2 to 3, in this state, the outer peripheral edge P of the outer peripheral surface of the non-contact lip 37 is the inner end in the radial direction of each outer diameter side stepped portion 17. It is arranged at a radial position inside the edge Q.

  Further, in the case of this example, the outer peripheral edge P in the axial direction of the outer peripheral surface of the non-contact lip 37 is included in the virtual plane including the central axis of the hub body 9 and passing through each outer diameter side stepped portion 17. The outer diameter side step portion 17 is disposed at a radial position inside the tangent line α at the radially inner end edge Q. Or although illustration is abbreviate | omitted, the axial direction outer end edge P is arrange | positioned in the radial direction position which the said tangent (alpha) passes.

  Further, in this example, in this state, as shown in FIGS. 1 and 4, the maximum diameter portion 27 of the outer peripheral surface of the head 26 of each stud bolt 4 is in the radial direction with the outer peripheral surface of the non-contact lip 37. Is superimposed.

  Further, in the sealing material 30, the portion to which the base end portion of the non-contact lip 37 is connected is almost the entire surface of the outward flange portion 32 constituting the core metal 29 (the radially inner end of the inner surface in the axial direction). An outer diameter side cover portion 38 that covers a portion other than the portion) is provided. The axially inner side surface of the outward flange 32 is abutted against the axially outer end surface of the outer ring 1 with a part of the outer diameter side cover 38 interposed therebetween. In the case of this example, a dam portion 39 is constituted by a portion of the outward flange portion 32 and the outer diameter side cover portion 38 that protrudes radially outward from the axial outer end portion of the outer ring 1. .

  In the case of the rolling bearing unit for supporting a wheel according to the present example having the above-described configuration, the outer ring 1 protrudes radially outward from the axial outer end of the outer ring 1 at a position adjacent to the outer side in the axial direction. The dam portion 39 is provided. For this reason, even when water such as rain water and muddy water adhering to the outer peripheral surface of the outer ring 1 flows axially outward along the outer peripheral surface of the outer ring 1, the water is blocked by the dam portion 39. Thus, it is possible to prevent this moisture from reaching the third contact lip 36 through the portion between the axially outer end surface of the outer ring 1 and the axially inner surface of the rotation side flange 11.

  Further, in the case of this example, the tip of the non-contact lip 37 is made to face and oppose to the radially outer end of the radially inner step 18 provided on the axially inner surface of the rotating flange 11 over the entire circumference. As a result, a labyrinth seal is formed in the portion opposed to each other. For this reason, the amount of water such as rainwater and muddy water splashed from the road surface reaching the third contact lip 36 can be reduced.

  In the case of this example, the axial outer end edge P of the outer peripheral surface of the non-contact lip 37 is the radial inner end of each outer diameter step 17 provided on the axial inner surface of the rotation side flange 11. It is located radially inward from the edge Q. Furthermore, the tangent line α at the radially inner end edge Q of each outer diameter side stepped portion 17 in the imaginary plane including the central axis of the hub body 9 is the axial outer edge P of the outer peripheral surface of the non-contact lip 37. (Or the tangent line α is in contact with the outer edge P in the axial direction). For this reason, when the automobile stops while moisture is attached to the axial inner surface of the rotation side flange 11 by traveling on a wet road surface, the vehicle is provided on the axial inner surface of the rotation side flange 11. 1-2, the moisture adhering to the inner surface of the concave portion 14 located at the upper part in the vertical direction as shown in FIGS. 1-2 is vertically lowered along the inner surface of the concave portion 14 due to gravity (radial direction). When flowing inwardly, this moisture efficiently transfers from the outer diameter side step portion 17 constituting the radially inner end portion of the inner surface of the concave portion 14 to the outer peripheral surface of the non-sliding contact lip 37. Then, the moisture transferred to the outer peripheral surface of the non-sliding contact lip 37 moves downward along the outer peripheral surface and is discharged while moving toward the base end side of the outer peripheral surface. Therefore, in the case of this example, the moisture adhering to the axial inner side surface of the rotation side flange 11 is correspondingly between the axial inner side surface of the rotation side flange 11 and the tip of the non-contact lip 37. Thus, the amount reaching the third contact lip 36 through the gap existing in is reduced.

  Furthermore, in the case of this example, the outer peripheral surface of the head portion 26 constituting the plurality of stud bolts 4 has a maximum diameter portion 27 at the center portion in the axial direction, and the generatrix is a convex curved surface having an arc shape. In addition, the maximum diameter portion 27 is located on the axially inner side of the outer peripheral edge P of the outer peripheral surface of the non-contact lip 37 and overlaps the outer peripheral surface of the non-contact lip 37 in the radial direction. Yes. For this reason, when the automobile stops in a state where moisture adheres to the axial inner side surface of the rotation side flange 11 by traveling on a wet road surface, among the axial inner side surfaces of the rotation side flange 11, As shown in FIG. 4, the moisture adhering to the upper side of the stud bolt 4 located at the upper part of the rotating side flange 11 flows downward along the axial inner surface of the rotating side flange 11, and the stud When adhering to the outer peripheral surface of the head portion 26 of the bolt 4, the moisture is collected along the outer peripheral surface of the head portion 26 at the lower end portion of the maximum diameter portion 27 of the outer peripheral surface. Drops downward and transfers to the outer peripheral surface of the non-sliding lip 37. Then, the moisture transferred to the outer peripheral surface of the non-sliding lip 37 is discharged downward along the outer peripheral surface. Therefore, in the case of this example, the water adhering to the inner surface in the axial direction of the rotation side flange 11 is also caused by this between the axial inner surface of the rotation side flange 11 and the tip of the non-contact lip 37. The amount reaching the third contact lip 36 through the gap existing therebetween can be reduced. In addition, the moisture which did not adhere to the head 26 of the stud bolt 4 is transferred from the outer diameter side step portion 17 to the outer peripheral surface of the non-contact lip 37 and moved downward similarly to the moisture attached to the concave portion 14. Discharged.

  When the present invention is implemented, as a modification of the first example of the above-described embodiment, as shown in FIG. 5, the center axis of the hub body 9 (see FIG. 1) is included and each outer diameter side is included. In an imaginary plane passing through the stepped portion 17a, the axial outer end edge P of the outer peripheral surface of the non-contact lip 37 is positioned radially inside the extension line β extending inward in the axial direction of each outer diameter side stepped portion 17a. (Or although not shown, the axially outer edge P is disposed at a radial position through which the tangent line β passes) may be employed. Even when such a configuration is adopted, the moisture adhering to the inner surface of the recess 14 is directed radially inward along the inner surface of the recess 14 as in the case of the first example of the embodiment described above. When flowing, the moisture can be efficiently transferred from the outer diameter side stepped portion 17a constituting the radially inner end portion of the inner surface of the concave portion 14 to the outer peripheral surface of the non-sliding contact lip 37.

  Further, when implementing the present invention, as a modification of the first example of the above-described embodiment, the inner diameter side stepped portion 18 is curvedly inclined in the direction toward the inner side in the axial direction toward the inner side in the radial direction. It can also be a curved surface (the busbar shape is a concave arc shape). Similarly, as a modification, a hub is provided in a radial range sandwiched between a radial range in which the outer diameter side step portions 17 and 17 are provided and a radial range in which the inner diameter side step portion 18 is provided. It is also possible to provide a configuration in which a ring-shaped plane portion orthogonal to the central axis of the main body 9 is provided and the tip portion of the non-contact lip 37 is closely opposed over the entire outer periphery of the plane portion in the radial direction. it can.

[Second Example of Embodiment]
A second example of the embodiment of the present invention will be described with reference to FIGS.
In the case of this example, of the heads 26a constituting the plurality of stud bolts 4a, an arc that protrudes toward the center axis of each stud bolt 4a at the inner end portion in the radial direction of the rotation side flange 11 A shape cutout 40 is provided. Thus, the stud bolts 4a can be exchanged (the shaft portion 25 is inserted into and removed from the insertion hole 22) without interference between the head 26a of the stud bolts 4a and the outer ring 1. The notch 40 is formed in a state where the entire axial width of the head portion 26a is notched. Further, in the state where the stud bolt 4 a is positioned at the uppermost portion in the vertical direction, both circumferential ends of the notch 40 are positioned vertically downward with respect to the circumferential central portion of the notch 40.

In the case of this example having such a configuration, moisture adhering to the outer peripheral surface of the head portion 26a of the stud bolt 4a located at the upper portion of the rotation side flange 11 is removed from the maximum diameter portion 27 of the outer peripheral surface. Since it can be dripped from the both ends of the notch 40 regarding the circumferential direction, the dripping position of the water | moisture content from this outer peripheral surface can be controlled more correctly.
Other configurations and operations are the same as those in the first example of the embodiment described above.

  The present invention can be implemented by appropriately combining the configurations of the above-described embodiments (including modifications).

The wheel support rolling bearing unit of the present invention is not limited to a wheel support rolling bearing unit for a driven wheel, but can also be applied to a wheel support rolling bearing unit for a drive wheel.
When the present invention is carried out, the mating surface with which the sliding contact lip constituting the seal ring is slidably contacted can be, for example, the surface of a sliding contact ring made of a metal plate supported and fixed to the hub.

DESCRIPTION OF SYMBOLS 1 Outer ring 2 Hub 3 Rolling element 4, 4a Stud bolt 5 Seal ring 6 Cap 7 Static side flange 8a, 8b Outer ring raceway 9 Hub body 10 Inner ring 11 Rotation side flange 12a, 12b Inner ring raceway 13 Small diameter step part 14 Recessed part 15 Thin part 16 Thick portion 17, 17a Outer diameter side step portion 18 Inner diameter side step portion 19 Ring surface portion 20 Curved surface portion 21 Cylindrical surface portion 22 Insertion hole 23 Caulking portion 24 Cage 25 Shaft portion 26, 26a Head portion 27 Maximum diameter portion 28 Internal space DESCRIPTION OF SYMBOLS 29 Metal core 30 Sealing material 31 Fitting cylinder part 32 Outward flange part 33 Inner diameter support part 34 First contact lip 35 Second contact lip 36 Third contact lip 37 Non-contact lip 38 Outer diameter side cover part 39 Weir part 40 Notch

Claims (3)

An outer ring that has an outer ring raceway on its inner peripheral surface and does not rotate during use;
A hub having an inner ring raceway in a portion of the outer peripheral surface facing the outer ring raceway, and a rotation side flange for supporting and fixing a wheel in a portion of the outer peripheral surface located outside the outer ring in the axial direction. When,
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 an axial outer end opening of an internal space existing between an inner peripheral surface of the outer ring and an outer peripheral surface of the hub in a state of being supported and fixed to the outer end portion in the axial direction of the outer ring. ,
The rotation-side flange includes a recess provided in a state of being axially recessed at each of a plurality of locations in the circumferential direction of the radially inner portion or outer end of the axial inner side surface, and a radially inner portion of the inner surface of each of the recesses. Each of which is provided at each end, and has a stepped portion that is inclined in the direction toward the inner side in the axial direction toward the inner side in the radial direction,
The seal ring has a contact lip made of an elastic material, and a non-contact lip made of an elastic material provided radially outside the contact lip.
The contact lip is slidably in contact with the other surface rotating relative to the outer ring.
The non-contact lip is inclined in the direction toward the radially outer side from the base end portion which is the inner end portion in the axial direction toward the front end portion which is the outer end portion in the axial direction. The axially outer end edge of the outer peripheral surface is close to and opposed to the portion adjacent to the radially inner side with respect to the radial position where each step portion exists in the axially inner side surface of A wheel bearing rolling bearing unit that is disposed at the same radial position as the radially inner end edge of each stepped portion, or at a radially located position inside the radially inner end edge of each stepped portion. In a virtual plane that includes the central axis of the hub and passes through the stepped portion, the axially outer edge of the outer peripheral surface of the non-contact lip is tangent to the radially inner end edge of the stepped portion or the stepped portion. The rolling bearing unit for wheel support according to claim 1, wherein the rolling bearing unit is disposed at a radial position through which an extension line of the portion passes, or at a radial position inside the tangent line or the extension line. The shaft portion is fixed to the inner end portion in the axial direction of the shaft portion, and has a larger diameter dimension on the outer peripheral surface than the shaft portion, and other portions located on both sides in the axial direction in the axial intermediate portion of the outer peripheral surface. And further comprising a stud bolt having a head portion having a maximum diameter portion having a larger diameter dimension,
The rotation-side flange has an insertion hole provided in a state sandwiched between the recesses adjacent to each other in the circumferential direction so as to penetrate the portion in the axial direction.
The stud bolt has an outer peripheral surface of the head in a state where the shaft portion is inserted through the insertion hole and an axial outer surface of the head is in contact with an axial inner surface of the rotating flange. The wheel bearing rolling bearing unit according to any one of claims 1 to 2, wherein a maximum diameter portion of the wheel overlaps with an outer peripheral surface of the non-contact lip in a radial direction.

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