JP2017026118A - Wheel support rolling bearing unit, manufacturing method thereof and seal ring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure of a wheel support rolling bearing unit which hardly causes initial grease leakage at a slide-contact part between a tip and a mating face of a side lip, and its manufacturing method.SOLUTION: In a state that tips of inside/outside side lips 27, 28 are not made to contact with an inside face of a rotation-side flange in an axial direction yet, grease 33b, 33c for forming a fluid lubrication film is applied on a portion deviated from the tips out of internal peripheral faces of the inside/outside side lips 27, 28 in advance. In this state, the tips of the inside/outside side lips 27, 28 are made to contact with the inside face of the rotation-side flange in the axial direction while having fastening margins over the whole periphery, and the grease 33b, 33c is made to contact with the inside face of the flange.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a rolling bearing unit for supporting a wheel for supporting a wheel of an automobile on a suspension device, a manufacturing method thereof, and an improvement of a seal ring used by being incorporated in a rotating machine such as a rolling bearing unit for supporting a wheel.

In Patent Document 1, regarding the rolling bearing unit for supporting a wheel of an automobile, the front ends of a plurality of seal lips constituting a seal ring that closes the axially outer end opening of the rolling element installation space, and the surface of the hub as a mating surface, It is described that by forming a fluid lubrication film between the two (sliding contact portions), the frictional resistance of each sliding contact portion is kept low and the sealing property of each sliding contact portion is secured. Among the seal lips, a part of the seal lips is a radial lip whose tip is in sliding contact with the outer peripheral surface of the hub, and the remaining seal lips are in the axial direction of the rotation side flange constituting the hub. It is a side lip which makes a front-end | tip part slidably contact with an inner surface.
In the present specification and claims, “outside” with respect to the axial direction refers to the outside in the width direction of the vehicle when assembled to the automobile, and “inside” with respect to the axial direction refers to the automobile. In the assembled state, the center side in the width direction of the vehicle is said.

  Further, in Patent Document 1, when manufacturing the wheel-supporting rolling bearing unit, the fluid lubrication film is formed in advance at the tip of each seal lip prior to assembling the seal ring. The method of applying the grease is described.

  In the case of a wheel bearing rolling bearing unit manufactured by the conventional manufacturing method as described above, at the start of use, at the sliding contact portion between the tip end portion of the side lip and the axial inner side surface of the rotating side flange, Although it is slight, it may cause initial grease leakage. This point will be described below.

  The centrifugal force generated by the rotation of the hub during operation of the wheel bearing rolling bearing unit is caused by the presence of grease existing in the sliding contact portion between the distal end portion of the radial lip and the outer peripheral surface of the hub. It does not act in the direction of axial movement along the outer peripheral surface (which causes grease leakage at the sliding contact portion). On the other hand, the centrifugal force causes the grease existing in the sliding contact portion between the tip portion of the side lip and the axial inner side surface of the rotation side flange to radially extend along the axial inner side surface of the rotation side flange. It acts in the direction of moving outward (causing grease leakage at the sliding contact portion).

In general, the thickness of the fluid lubricating film at the sliding contact portion between the tip of each seal lip (radial lip, side lip) and the mating surface is about several μm (μm unit). Prior to assembling, it is difficult to apply grease to the tip of each seal lip in advance with the same thickness as the fluid lubrication film. For this reason, the thickness of the grease applied at this time is usually considerably larger than the thickness of the fluid lubricating film.
Accordingly, in a state immediately after the seal ring is assembled, the amount of grease is excessive in the sliding contact portion between the tip portion of each seal lip (radial lip, side lip) and the mating surface.
As a result, at the start of use of the wheel supporting rolling bearing unit, a part of excess grease existing in the sliding contact portion between the tip end portion of the side lip and the axial inner surface of the rotating side flange is caused by centrifugal force. There is a possibility of moving radially outward along the axial inner surface of the rotating flange (initial grease leakage occurs at the sliding contact portion).

In addition, there are Patent Documents 2 and 3 as other prior art documents related to the present invention.
Patent Document 2 describes that grease leakage is induced by vibration during conveyance of a wheel-supporting rolling bearing unit.
Patent Document 3 describes a method of applying a wax used as an initial lubricant on a sliding surface of a seal lip.

JP 2006-046518 A JP 2014-077499 A JP-A-9-133218

  In view of the circumstances as described above, the present invention provides a structure of a rolling bearing unit for wheel support, a manufacturing method thereof, and a seal, in which initial grease leakage is unlikely to occur at a sliding contact portion between a tip portion of a side lip and a mating surface. It was invented to realize the ring structure.

Among the present inventions, the seal ring described in claim 1 includes a sealing material made of an elastic material.
The sealing material includes a side lip that is slidably contacted in a state where the tip end portion has a tightening margin with respect to the axial side surface of the rotating member that rotates during use in a state where the seal ring is assembled at a use location. I have.
Further, in a state before being assembled to the use location, a tip portion of the side lip and an axial side surface of the rotating member are disposed on a portion of the inner peripheral surface of the side lip that is separated from the tip portion of the side lip. Grease for forming a fluid lubrication film on the sliding contact portion is applied (in such a manner that the grease can be brought into contact with the axial side surface of the rotating member when the seal ring is assembled to the use location) The tip of the side lip is not coated with the grease.

A wheel support rolling bearing unit according to a second aspect 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 is a rotating member that rotates when in use, and has an inner ring raceway on an outer peripheral surface, is disposed coaxially with the outer ring on the radially inner side of the outer ring, and is outside of the outer ring in the axial direction of the outer ring. A rotation-side flange for supporting the wheel is formed at a portion protruding axially outward from the end portion.
Each rolling element is provided between the outer ring raceway and the inner ring raceway so as to be freely rollable.
The seal ring is the seal ring according to claim 1, wherein the seal ring is supported and fixed to the outer end portion in the axial direction of the outer ring, and the inner peripheral surface of the outer ring and the outer peripheral surface of the hub. The axial direction outer end opening part of the internal space (rolling body installation space) which exists in between is blocked.
Further, the tip of the side lip constituting the seal ring is in contact with the inner side surface in the axial direction of the rotary flange with a tightening margin on the entire circumference.
Further, the grease is in contact with a portion of the inner side surface in the axial direction of the rotation side flange that is closer to a radially inner side than a portion with which the tip portion of the side lip is in contact, and the tip of the side lip It does not touch the part that the part is in contact with.

  When carrying out the rolling bearing unit for supporting a wheel of the present invention, preferably, as in the invention described in claim 3, the volume of the grease is set to the surface of the sealing material constituting the seal ring and the hub. (E.g., a plurality of seal lips including the side lip constituting the seal material and positioned between the side lip and the other seal lip adjacent to each other), The volume of the enclosed grease space can be 20% or less.

  Among the present inventions, a manufacturing method according to claim 4 is a method for manufacturing a wheel-supporting rolling bearing unit according to any one of claims 2 to 3, wherein the above-mentioned claim 1. After making the seal ring described in the above, the tip end portion of the side lip constituting the seal ring is brought into contact with the axially inner side surface of the rotary side flange in a state having a tightening allowance on the entire circumference, and Grease is brought into contact with a portion of the inner side surface in the axial direction of the flange on the rotating side that is closer to the inside in the radial direction than the portion with which the tip portion of the side lip is in contact, and the tip portion of the side lip is in contact with the grease. Do not touch the part.

  When the present invention is carried out, the grease is spread over the entire periphery of the inner peripheral surface of the side lip in a state where it is removed from the tip end portion of the side lip before the seal ring is assembled to the place of use. It can also apply | coat to cyclic | annular form, or can also apply | coat intermittently (at several places spaced apart in the circumferential direction) regarding the circumferential direction.

According to the seal ring of the present invention as described above, at the start of use of the rotary machine incorporating the seal ring, the tip of the side lip constituting the seal ring and the axial side surface of the rotary member (sliding contact). Part) can prevent initial grease leakage.
That is, in the case of the seal ring of the present invention, the grease is applied to the portion of the inner peripheral surface of the side lip that is detached from the tip of the side lip in a state before being assembled at the use location. The grease is not applied to the tip of the side lip. For this reason, the axial side surface of the rotating member and the side lip of the side lip are in a state immediately after the tip of the side lip is brought into contact with the entire side of the axial side surface of the rotating member. It is possible to prevent an excessive amount of grease from being present in the sliding contact portion with the tip portion. Therefore, at the start of use of the rotary machine incorporating the seal ring, a part of the excessive amount of grease existing in the sliding contact portion moves radially outward along the axial side surface of the rotary member by centrifugal force. This prevents the inconvenience that initial grease leakage occurs at the sliding contact portion.

According to the wheel-supporting rolling bearing unit and the manufacturing method thereof of the present invention as described above, at the start of use of the wheel-supporting rolling bearing unit, the tip end portion of the side lip constituting the seal ring and the axial inside of the rotary side flange It is possible to prevent initial grease leakage between the side surfaces (sliding contact portion).
That is, in the case of the rolling bearing unit for supporting a wheel and the manufacturing method thereof according to the present invention, the tip end portion of the side lip is in contact with the inner peripheral surface in the axial direction of the rotating side flange in a state having a tightening allowance. It is possible to prevent an excessive amount of grease from being present in the sliding contact portion between the axially inner side surface of the rotation side flange and the tip end portion of the side lip immediately after the operation. Therefore, at the start of use of the wheel support rolling bearing unit, a part of the excessive amount of grease existing in the sliding contact portion moves radially outward along the axial inner surface of the rotating flange by centrifugal force. This prevents the inconvenience that initial grease leakage occurs at the sliding contact portion.

Sectional drawing of the rolling bearing unit for wheel support used as the object of the 1st example of embodiment of this invention. The A section enlarged view of FIG. 1 which abbreviate | omits and shows a part. Sectional drawing of a seal ring shown in the state before making three seal lips contact the surface of a hub main body. FIG. 3 is a view similar to FIG. 2, showing a state immediately after the three seal lips are brought into contact with the surface of the hub body so as to have a predetermined tightening allowance. The figure similar to FIG. 3 which shows the 2nd example of embodiment of this invention.

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

  The outer ring 2 does not rotate while being supported and fixed to the suspension device during use. Such an outer ring 2 has double row outer ring raceways 7a and 7b at the axially intermediate portion of the inner peripheral surface, and a stationary flange 8 for supporting and fixing the suspension device to the suspension device at the axially intermediate portion of the outer peripheral surface. .

The hub 3 is a rotating member that rotates together with the wheel while the wheel (driven wheel) is supported and fixed in use. Such a hub 3 is formed by combining a hub body 9, an inner ring 10 and a nut 14.
Of these, the outer peripheral surface of the hub body 9 is provided with a rotation side flange 11 for supporting and fixing the wheel near the outer end in the axial direction, and the axial direction of the double-row inner ring raceways 12a and 12b at the intermediate portion in the axial direction. The outer inner ring raceway 12a is provided with a small-diameter step 13 at the inner end in the axial direction.
On the outer peripheral surface of the inner ring 10, an inner ring raceway 12b on the inner side in the axial direction of the double row inner ring raceways 12a and 12b is provided. Such an inner ring 10 is fitted in the axial direction by the nut 14 which is screwed into a male screw portion provided at the inner end portion in the axial direction of the hub body 9 and further tightened in a state of being fitted on the small diameter step portion 13. The inner end face is held down so as to be coupled and fixed to the hub body 9. In addition, in order to couple and fix the hub body and the inner ring, instead of the structure in which the nut 14 is screwed into the axially inner end of the hub body 9 as shown in the drawing, the axially inner end of the hub body is radially A structure may be employed in which the inner end surface in the axial direction of the inner ring that is externally fitted to the small-diameter step portion of the hub body is suppressed by a caulking portion formed by plastic deformation outward.

  Each of the rolling elements 4, 4 rolls in a state where a plurality of rolling elements are held by the cages 15a, 15b for each row between the outer ring raceways 7a, 7b and the inner ring raceways 12a, 12b. It is provided freely. In the example shown in the figure, balls are used as the rolling elements 4 and 4. However, in the case of a rolling bearing unit for supporting a wheel for an automobile having a heavy weight, a tapered roller may be used.

The seal ring 5 is present between the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the hub 3 in a state where the seal ring 5 is supported and fixed to the outer end portion in the axial direction of the inner peripheral surface of the outer ring 2. The axial outer end opening of the cylindrical internal space 16 in which the rolling elements 4 and 4 are installed is closed. The internal space 16 is filled with grease.
Such a seal ring 5 includes a metal core 17 and a seal material 18.

The metal core 17 is formed in an annular shape by pressing a metal plate such as a mild steel plate, and includes a fitting tube portion 19 and an outer edge in the axial direction of the fitting tube portion 19. And an annular portion 20 formed so as to be bent radially inward.
Among these, the fitting cylinder part 19 is formed in a cylindrical shape whose outer diameter dimension and inner diameter dimension do not change over the entire length in the axial direction.
The annular portion 20 includes an outer conical cylinder portion 21, an outer annular portion 22, an inner conical cylinder portion 23, and an inner annular portion 24.
Out of these, the outer cone cylinder portion 21 is formed in a state of being bent (inclined) from the outer edge in the axial direction of the fitting cylinder portion 19 outward in the axial direction and radially inward.
The outer ring portion 22 is formed in a state of being bent radially inward from the radially inner end edge (axial outer end edge) of the outer cone tube portion 21.
The inner conical cylinder portion 23 is formed in a state of being bent (inclined) inward in the axial direction and radially inward from the radially inner end edge of the outer annular portion 22.
The inner circular ring portion 24 is formed in a state of being bent radially inward from the radial inner end edge (axial inner end edge) of the inner conical cylinder portion 23.
The metal core 17 having such a configuration is supported on the outer end portion in the axial direction of the outer ring 2 by fixing the fitting tube portion 19 to the outer end portion in the axial direction of the outer ring 2 by an interference fit. It is fixed.

  The seal material 18 is made of an elastic material such as an elastomer such as rubber, and is fixedly bonded to the core metal 17. The seal base 18 and three contact-type seal lips (radial lip 26, inner side lip 27). And an outer side lip 28). FIG. 3 shows a state before the seal ring 5 is assembled at a use location {free state of the seal lips (25, 26, 27)}. FIGS. 2 and 4 show the use of the seal ring 5. The state after assembly | attaching to the location (The state which said each seal lip (25, 26, 27) elastically deformed) is shown. In the case of this example, the inner side lip 27 and the outer side lip 28 correspond to the side lips described in the claims.

  The seal base portion 25 has a substantially annular shape, and extends from the axially outer side surface (the outer peripheral surface of the outer conical cylinder portion 21) of the core metal 17 through the inner peripheral surface of the annular shape portion 20. The cored bar 17 (the inner annular ring part 24) is joined and fixed to the cored bar 17 in a state of covering a portion of the cored bar 17 (the inner circular ring part 24) that is hung on the radially inner end.

  The radial lip 26 extends from the portion of the seal base 25 that covers the inner peripheral surface of the annular portion 20 (inner annular portion 24) of the core bar 17 inward in the radial direction and axially inward. It is formed in the extended state. The tip (edge tip) of the radial lip 26 has a tightening margin on the entire circumference in a portion of the outer peripheral surface of the hub body 9 adjacent to the inner side in the axial direction of the rotating flange 11. In contact (sliding contact). In this state, at least a part of the radial lip 26 (the tip portion or the intermediate portion in the illustrated example) is the central axis of the outer ring 2 as shown in FIGS. It is elastically deformed in a direction in which the inclination angle with respect to a virtual plane orthogonal to is increased.

  The inner side lip 27 includes a cylindrical portion 29a and a conical cylindrical portion 30a. Of these, the cylindrical portion 29 a is formed in a state of extending outward in the axial direction from the radially inner end of the axially outer surface of the seal base 25. The conical cylinder portion 30a is formed in a state of extending radially outward and axially outward from the axial outer end edge of the cylindrical portion 29a. The front end (front end edge) of the inner side lip 27 is in contact (sliding contact) with the radially inner end of the axially inner side surface of the rotating flange 11 with a tightening margin on the entire circumference. doing. In this state, at least a part of the inner side lip 27 (in the illustrated example, the conical cylinder portion 30a) is the center of the outer ring 2 as shown in FIGS. It is elastically deformed in the direction in which the inclination angle with respect to the axis increases.

  The outer side lip 28 includes a cylindrical portion 29b and a conical cylindrical portion 30b. Of these, the cylindrical portion 29 b is formed so as to extend outward in the axial direction from a portion of the seal base 25 that covers the inner peripheral surface of the inner conical cylinder portion 23 of the core metal 17. The conical cylinder portion 30b is formed in a state of extending radially outward and axially outward from the axial outer end edge of the cylindrical portion 29b. The tip (tip edge) of the outer side lip 28 is in contact (sliding contact) with the entire inner circumference near the radially inner end of the rotary side flange 11 with a tightening margin. )doing. In this state, at least a part of the outer side lip 28 (in the illustrated example, the conical cylinder portion 30b) is the center of the outer ring 2 as shown in FIGS. 3 to 2 and FIG. It is elastically deformed in the direction in which the inclination angle with respect to the axis increases.

  Further, an inner grease space 31 defined between the surface of the hub body 9 and the surface of the sealing material 18, located between the radial lip 26 and the inner side lip 27, and the inner side lip 27, Grease 33a, 33b, and 33c are sealed in the outer grease space 32 positioned between the outer side lips 28, respectively. The inner grease space 31 and the outer grease space 32 correspond to the grease spaces described in the claims. The tip of the radial lip 26 and the outer peripheral surface of the hub body 9 that are in contact (sliding contact) with each other by a part of each of the greases 33 a, 33 b, 33 c, are axially inward of the rotary flange 11. Between a portion (sliding contact portion) between adjacent portions, and between a distal end portion of the inner side lip 27 that contacts (sliding contact) with each other, and a radially inner end portion of an axial inner side surface of the rotation side flange 11 A portion (sliding contact portion) between a portion (sliding contact portion) and a distal end portion of the outer side lip 28 that contacts (sliding contact) with each other and a radially inner end portion of the axial side surface of the rotation side flange 11 ), Fluid lubrication films 34a, 34b, and 34c are formed, respectively. Thus, the frictional resistance of each sliding contact portion is kept low, and the sealing performance of each sliding contact portion is ensured. The thickness of each fluid lubricating film 34a, 34b, 34c is several μm.

  The cover 6 is formed into a bottomed cylindrical shape by a metal plate such as a stainless steel plate or a mild steel plate, and is subjected to a rust prevention treatment such as cationic coating as required. In the state of closing the opening, it is fitted and fixed to the inner end of the outer ring 2 in the axial direction.

  In the case of this example, when assembling the wheel support rolling bearing unit 1 having the above-described configuration, the seal ring 5 is supported and fixed to the outer end of the outer ring 2 in the axial direction, and the outer ring on the outer side in the axial direction. The rolling elements 4 and 4 held by the axially outer cage 15a are held radially inside the track 7a by the axially inner cage 15b inside the axially inner outer ring raceway 7b. Each of the rolling elements 4, 4 thus arranged is arranged.

  At this stage, the fluid lubricating films 34a, 34b, 34c are formed on the three seal lips (26, 27, 28) constituting the seal ring 5 in the manner shown in FIG. For this purpose, greases 33a, 33b and 33c are applied. Specifically, with respect to the radial lip 26, the grease 33a is applied to the entire circumference of the tip portion to the intermediate portion of the inner peripheral surface. Further, with respect to the inner side lip 27, the grease 33b is applied to the entire circumference of the base half portion which is a portion removed from the tip end portion of the inner peripheral surface of the conical cylinder portion 30a. Further, with respect to the outer side lip 28, the grease 33c is applied to the entire circumference of the base half portion, which is a portion removed from the tip portion, of the inner peripheral surface of the conical cylinder portion 30b. The amount (volume) of each of the greases 33a, 33b, 33c applied to the three seal lips (26, 27, 28) forms the fluid lubrication films 34a, 34b, 34c, respectively. The amount is regulated so as not to become insufficient and excessive. Therefore, in the case of this example, in particular, the amount (volume) of the grease 33b applied to the inner side lip 27 is set to the volume of the inner grease space 31 in which the grease 33b is sealed in the assembled state. It is regulated to 20% or less (for example, about 5 to 15%). At the same time, the amount (volume) of the grease 33c applied to the outer side lip 28 is set to 20% or less (for example, 5 to 15%) of the volume of the outer grease space 32 in which the grease 33c is sealed in the assembled state. Degree). In this manner, the operation of applying the greases 33a, 33b, 33c to the three seal lips (26, 27, 28) in this manner is performed by attaching the seal ring 5 to the outer end of the outer ring 2 in the axial direction. It may be performed in a state before being supported and fixed (a state of the seal ring 5 alone), or may be performed in a state after the seal ring 5 is supported and fixed to the outer end of the outer ring 2 in the axial direction. good.

  In any case, as described above, the outer ring 2, the seal ring 5 coated with the greases 33a, 33b, and 33c, and the rolling elements 4 and 4 held by the cage 15a on the outer side in the axial direction. If the rolling elements 4 and 4 held by the cage 15b on the inner side in the axial direction are combined, in this state, the inner end of the hub body 9 in the axial direction through the inner side of the outer ring 2 The intermediate part is inserted from the outside in the axial direction. Thus, the rolling elements 4 and 4 held by the axially outer cage 15a are arranged between the outer ring raceway 7a on the outer side in the axial direction and the inner ring raceway 12a on the outer side in the axial direction. At the same time, as shown in FIG. 4, of the three seal lips (26, 27, 28) constituting the seal ring 5, the distal end portion of the radial lip 26 is connected to the outer peripheral surface of the hub body 9. The tip of the inner side lip 27 is located at a portion adjacent to the inner side in the axial direction of the rotating side flange 11, and the outer side lip 28 is positioned at the radially inner end of the inner side surface in the axial direction of the rotating side flange 11. The tip is brought into contact with a portion closer to the radially inner end of the axially inner side surface of the rotary flange 11 with a predetermined tightening margin over the entire circumference. At the same time, as shown in FIG. 4, the greases 33a, 33b, 33c applied to the three seal lips (26, 27, 28) are brought into contact with the surface of the hub body 9, respectively. Let

  Specifically, the grease 33 a applied to the entire circumference of the inner peripheral surface of the radial lip 26 is applied to the shaft of the rotary flange 11 in the outer peripheral surface of the hub body 9. Touch the adjacent part on the inside in the direction. In this state, a part of the grease 33 a is sandwiched between the tip end portion of the radial lip 26 and a portion of the outer peripheral surface of the hub body 9 adjacent to the axially inner side of the rotation side flange 11. The fluid lubrication film 34a is formed. Further, the grease 33b applied to the entire circumference of the base half portion of the inner peripheral surface of the conical cylinder portion 30a constituting the inner side lip 27 is radially inward of the axial inner side surface of the rotating side flange 11. Among the end portions, the inner side lip 27 is brought into contact with a position slightly inward in the radial direction from a portion where the tip portion of the inner side lip 27 contacts. In this state, the grease 33 b is not sandwiched between the tip end portion of the inner side lip 27 and the radially inner end portion of the axially inner side surface of the rotating side flange 11. Further, the grease 33c applied to the entire circumference of the base half portion of the inner peripheral surface of the conical cylinder portion 30b constituting the outer side lip 28 is radially inward of the axial inner side surface of the rotating side flange 11. Of the portions close to the end, the outer side lip 28 is brought into contact with a position slightly closer to the inside in the radial direction than the portion with which the tip of the outer side lip 28 contacts. In this state, the grease 33c is not sandwiched between the distal end portion of the outer side lip 28 and the radially inner end portion of the axially inner side surface of the rotating side flange 11.

  Thereafter, the inner ring 10 is externally fitted to the small diameter step portion 13 of the hub body 9. In this state, the nut 14 is screwed into a male thread portion provided at the inner end portion in the axial direction of the hub body 9 and further tightened, whereby the inner end surface in the axial direction of the inner ring 10 is suppressed by the nut 14. Thus, the hub body 9 and the inner ring 10 are coupled and fixed. Thereafter, the cover 6 is attached to the inner end of the outer ring 2 in the axial direction.

  In the case of the wheel bearing rolling bearing unit 1 assembled as described above, when the hub 3 is rotated at the start of use, the leading ends of the inner and outer side lips 27 and 28 and the rotation side are accordingly accompanied. The fluid lubrication films 34b and 34c are formed at sliding contact portions with the axially inner side surface of the flange 11, respectively.

  That is, when the hub 3 rotates as described above, a portion of the grease 33b that is in contact with the inner side surface in the axial direction of the rotation-side flange 11 rotates with the rotation-side flange 11 and is subjected to centrifugal force. It moves radially outward along the axially inner surface of the rotating flange 11. As a result, a part of the grease 33b enters between the front end portion of the inner side lip 27 and the inner side surface in the axial direction of the rotation side flange 11 (sliding contact portion), and the fluid lubrication is performed on the sliding contact portion. A film 34b is formed.

  Further, when the hub 3 rotates as described above, a portion of the grease 33c that is in contact with the inner side surface in the axial direction of the rotation side flange 11 rotates together with the rotation side flange 11 by centrifugal force. It moves radially outward along the axially inner surface of the rotating flange 11. As a result, a part of the grease 33c enters between the front end portion of the outer side lip 28 and the inner side surface in the axial direction of the rotating flange 11 (sliding contact portion), and the fluid contacts the sliding contact portions. A lubricating film 34c is formed.

  According to the wheel-supporting rolling bearing unit 1 and the manufacturing method thereof and the seal ring 5 of the present example as described above, at the start of use of the wheel-supporting rolling bearing unit 1, the inner side constituting the seal ring 5, It is possible to prevent initial grease leakage from occurring at the sliding contact portion between the front end portions of the outer side lips 27 and 28 and the inner side surface in the axial direction of the rotating flange 11. That is, in the case of this example, the inner and outer side lips are brought into contact with the inner side surface in the axial direction of the rotation side flange 11 before the tips of the inner and outer side lips 27 and 28 are brought into contact with each other. Greases 33b and 33c are applied to portions of the inner peripheral surfaces of the inner and outer side lips 27 and 28 that are separated from the tip portions of the inner and outer side lips 27 and 28, respectively. For this reason, in the state immediately after the front end portions of the inner and outer side lips 27 and 28 are brought into contact with the inner peripheral surface of the rotating side flange 11 with a tightening margin on the entire circumference, the rotation is performed. It is possible to prevent an excessive amount of grease 33b and 33c from being present between the axially inner side surface of the side flange 11 and the tip portions of the inner and outer side lips 27 and 28 (sliding contact portions). Accordingly, at the start of use of the wheel support rolling bearing unit 1, a part of the excessive amount of grease existing in each sliding contact portion has a diameter along the axial inner surface of the rotation side flange 11 due to centrifugal force. It is possible to prevent the inconvenience of moving outward in the direction (initial grease leakage occurs at each sliding contact portion).

  In the case of this example, the amount (volume) of the grease 33b applied to the inner side lip 27 is restricted to 20% or less of the volume of the inner grease space 31 in which the grease 33b is enclosed. . Accordingly, in the case of this example, it is possible to prevent the centrifugal force acting on the grease 33b during use from becoming excessively large. As a result, it is possible to prevent an excessive amount of grease 33b between the axial inner side surface of the rotating flange 11 and the tip end portion of the inner side lip 27 (sliding contact portion). Prevents grease leakage for a long time.

  In the case of this example, the amount (volume) of the grease 33c applied to the outer side lip 28 is restricted to 20% or less of the volume of the inner grease space 32 in which the grease 33c is enclosed. . Therefore, in the case of this example, it is possible to prevent the centrifugal force acting on the grease 33c during use from becoming excessively large. As a result, it is possible to prevent an excessive amount of grease 33c between the axial inner side surface of the rotation side flange 11 and the tip end portion of the outer side lip 28 (sliding contact portion). Prevents grease leakage for a long time.

  In the case of carrying out this example, the greases 33b and 33c applied to the inner peripheral surfaces of the inner and outer side lips 27 and 28 are not applied over the entire circumference but are separated from each other in the circumferential direction. It is also possible to apply only to the location (intermittently in the circumferential direction). Even in this case, if the respective greases 33b and 33c reach the sliding contact portions between the tip portions of the inner and outer side lips 27 and 28 and the axially inner side surface of the rotation side flange 11 after the start of use, Fluid lubrication films 34b and 34c can be formed on the entire circumference of the sliding contact portion.

[Second Example of Embodiment]
A second example of the embodiment of the present invention will be described with reference to FIG.
In the case of this example, with respect to the seal ring 5a before assembly of the wheel bearing rolling bearing unit, the application position of the grease 33a with respect to the inner peripheral surface of the radial lip 26 is the tip of the inner peripheral surface of the radial lip 26. Or only the entire circumference of the intermediate portion, not the entire circumference of the intermediate portion, so that the total amount of the grease 33a, and hence the total amount of grease in the inner grease space 31 (see FIGS. 2 and 4) after assembly, The number is smaller than in the first example of the embodiment described above.
This prevents the grease leakage phenomenon described in paragraphs [0006] to [0008] of Patent Document 2 from occurring at the seal ring 5a.
That is, the base oil separated from the grease in the internal space 16 (see FIG. 1) due to the vibration during the conveyance of the wheel support bearing unit causes the radial lip 26 and the hub body to be separated by the internal pressure and capillary action of the internal space 16. 9 (see FIGS. 1, 2, and 4), after entering the inner grease space 31 through a minute gap that exists in the sliding contact portion with the outer peripheral surface, the greases 33 a and 33 b (increase in the inner grease space 31) The volume of the greases 33a and 33b is increased by being absorbed by the agent (the inner grease space 31 is filled with the greases 33a and 33b), so that the greases 33a and 33b are connected to the inner side lip 27 and the rotation side. The flange 11 (see FIGS. 1, 2, and 4) reaches the sliding portion with the inner side surface in the axial direction. 2 and 4), and repeated at the sliding contact portion between the outer side lip 28 and the inner side surface in the axial direction of the rotation side flange 11, it is possible to prevent inconvenience that grease leaks to the outer space. I am trying to do it.

  Although not shown in the drawings, when the tip of the radial lip 26 is brought into contact with the outer peripheral surface of the hub body 9 over the entire circumference with a predetermined tightening margin, the grease 33a is Of the outer peripheral surface of the hub main body 9, the hub body 9 comes into contact with a position slightly shifted outward in the axial direction from the contact portion with the tip portion of the radial lip 26. The grease 33a moves toward the sliding contact portion between the distal end portion of the radial lip 26 and the outer peripheral surface of the hub body 9 with the rotation after the start of use, and the fluid lubrication film is formed at the sliding contact portion. 34a is formed.

In the case of this example, before applying the grease 33a, 33b, 33c to the inner peripheral surfaces of the three seal lips (26, 27, 28) constituting the seal ring 5a, the base oil of the grease is used. 35a, 35b, and 35c are applied.
Specifically, with respect to the radial lip 26, the entire circumference of the front half portion (the range indicated by the broken line in FIG. 5) including the tip portion, which is the portion to which the grease 33a is not applied, of the inner peripheral surface, Base oil 35a is applied. The tip of the grease 33a to be applied thereafter is applied from above the rear end of the base oil 35a.
Further, with respect to the inner side lip 27, a tip end portion to an intermediate portion (a range indicated by a broken line in FIG. 5) including a tip half portion that is a portion where the grease 33b is not applied on the inner peripheral surface of the conical cylinder portion 30a. The base oil 35b is applied to the entire circumference. The tip of the grease 33b to be applied thereafter is applied from above the rear end of the base oil 35b.
Further, with respect to the outer side lip 28, the tip end portion to the intermediate portion (the range indicated by the broken line in FIG. 5) including the tip half portion of the inner peripheral surface of the conical cylinder portion 30b where the grease 33c is not applied. The base oil 35c is applied to the entire circumference. The tip of the grease 33c to be applied thereafter is applied from above the rear end of the base oil 35c.
In addition, the application work of the base oils 35a, 35b, and 35c as described above is performed, for example, by applying a sponge (stamp base) soaked with the base oil to the application position on the inner peripheral surface of each seal lip (26, 27, 28). ), Or by rolling a sponge roller soaked with base oil at the application position.

In the case of this example as described above, the base oils 35a, 35b, and 35c are transferred to the front ends of the seal lips (26, 27, and 28) and the hub at the start of use of the wheel support rolling bearing unit. By using it as an initial lubricant at the sliding contact portion with the surface of the main body 9, it is possible to more surely prevent the initial wear of the tip portion of each seal lip (26, 27, 28). Further, based on the presence of the base oils 35a, 35b, and 35c, the greases 33a, 33b, and 33c are moved between the front ends of the seal lips (26, 27, and 28) and the surface of the hub body 9. Since it can be moved to the sliding contact portion at an early stage, the fluid lubrication films 34a, 34b, 34c can be formed at an early stage on each sliding contact portion. The base oils 35a, 35b, and 35c can be thinly applied to the distal end portions of the inner peripheral surfaces of the seal lips (26, 27, and 28). For this reason, at the start of use of the wheel bearing rolling bearing unit, the base oils are slidably contacted with the tip portions of the inner and outer side lips 27 and 28 and the axially inner side surface of the rotating flange 11. It is possible to prevent the initial leakage of 35a, 35b, and 35c.
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 replacing the base oils 35a, 35b, and 35c of the second example of the above-described embodiment with wax. The method for applying the wax is not particularly limited. For example, the application method described in Patent Document 3 can be employed.

An experiment conducted for confirming the effect of the present invention will be described.
In this experiment, the wheel support rolling bearing unit 1 of the first example of the above-described embodiment is targeted, and the inner peripheral surface of the side lip (outer side lip 28) constituting the seal ring 5 is disengaged from the tip portion. The amount of grease (33c) applied to the portion (the base half of the inner peripheral surface of the conical cylinder portion 30b) was varied {the ratio of the volume of the outer grease space 32 to 10%, 15%, 20%, 25% , 30%} were prepared. For each sample, after assembling, an operation of rotating the hub 3 at 2000 min ⁻¹ is performed for 24 hours while applying a straight load of the vehicle, and the axial direction of the distal end portion of the side lip and the rotation side flange 11 is performed. It was confirmed whether or not grease leakage occurred at the sliding contact portion with the inner side surface (“presence of leakage”).

  When preparing each sample, the application of the grease to the inner peripheral surface of the side lip was automatically performed using a greasing machine. When applied in an annular shape, it becomes difficult to bring the grease into contact with the inner side surface in the axial direction of the rotation side flange 11 during assembly. For this reason, for the sample with a small amount of application (10%), one type of the grease applied as “intermittent” (method of applying intermittently in the circumferential direction) is prepared, and the amount of application is large ( Samples of 25% and 30%) were prepared with one type of grease applied in a “ring shape” (how to apply in a ring shape over the entire circumference), and the amount applied was medium (15%, 20%). Two types of samples were prepared with the grease applied as “intermittent” or “annular”. For each type of sample, the above-described operation and grease leakage were confirmed three times.

The experimental results are shown in Table 1 below.

As apparent from the above experimental results, it was found that grease leakage did not occur when the application amount was 20% or less, and grease leakage occurred when the application amount exceeded 20%.
Moreover, there is almost no difference in the distribution of residual grease after the end of the experiment between the case where the coating amount is “intermittent” and the case where it is “annular” from a sample with a medium coating amount (15%, 20%). It was confirmed that the fluid lubrication film can be formed.
In addition, the wax component of the rubber constituting the sealing material 18 is effective because no abnormalities such as initial wear were observed at the tip of the side lip for all samples including each sample having an application amount of 20% or less. It was confirmed that a fluid lubricating film was formed relatively early.

The seal ring of the present invention is not limited to a wheel bearing rolling bearing unit, and can be used in a state of being incorporated in various rotating machines.
Further, when the present invention is carried out, the grease application position and application amount on the part of the inner peripheral surface of the side lip that is off the tip are limited to the positions and amounts employed in the above-described embodiments. The tip of the side lip was brought into contact with the mating surface (the axially inner side surface of the rotating flange, the axially side surface of the rotating member) so as to have a predetermined tightening margin over the entire circumference. If the position and amount of the grease come into contact with the mating surface in the state (but preferably 20% or less of the volume of the grease space in which the grease is sealed), various positions and amounts are adopted. I can do things.

DESCRIPTION OF SYMBOLS 1 Rolling bearing unit for wheel support 2 Outer ring 3 Hub 4 Rolling body 5, 5a Seal ring 6 Cover 7a, 7b Outer ring track 8 Stationary side flange 9 Hub body 10 Inner ring 11 Rotating side flange 12a, 12b Inner ring track 13 Small diameter step part 14 Nut 15a, 15b Cage 16 Internal space 17 Core metal 18 Sealing material 19 Fitting cylinder part 20 Annular part 21 Outer cone part 22 Outer annular part 23 Inner cone part 24 Inner annular part 25 Seal base 26 Radial lip 27 Inner side lip 28 Outer side lip 29a, 29b Cylindrical part 30a, 30b Conical cylinder part 31 Inner grease space 32 Outer grease space 33a, 33b, 33c Grease 34a, 34b, 34c Fluid lubrication film 35a, 35b, 35c Base oil

Claims (4)

A seal ring provided with an elastic sealant,
The sealing material includes a side lip that is slidably contacted in a state where the tip end portion has a tightening margin with respect to the axial side surface of the rotating member that rotates during use in a state where the seal ring is assembled at a use location. Has
In a state before being assembled to the use location, a portion of the inner peripheral surface of the side lip that is separated from the tip of the side lip is slid between the tip of the side lip and the axial side surface of the rotating member. Grease for forming a fluid lubrication film is applied to the contact portion, and the grease is not applied to the end portion of the side lip,
Seal ring. An outer ring that has an outer ring raceway on the inner peripheral surface, and that does not rotate while being supported and fixed to a suspension device during use;
An outer ring has an inner ring raceway, and is arranged coaxially with the outer ring on the radially inner side of the outer ring, and a wheel is projected on a part of the outer peripheral surface that protrudes axially outward from the axial outer end of the outer ring. A hub that is a rotating member that rotates when in use, on which a rotating flange for support is formed,
A plurality of rolling elements provided between the outer ring raceway and the inner ring raceway so as to freely roll;
The axial outer end opening of an internal space existing between the inner peripheral surface of the outer ring and the outer peripheral surface of the hub is closed in a state of being supported and fixed to the outer end portion in the axial direction of the outer ring. With the described seal ring,
The tip portion of the side lip constituting the seal ring is in contact with the axially inner side surface of the rotation side flange in a state having a tightening allowance on the entire circumference,
The grease is in contact with a portion of the inner side surface in the axial direction of the rotation side flange that is closer to the inside in the radial direction than the portion with which the tip portion of the side lip is in contact, and the tip portion of the side lip is Does not touch the touching part,
This is a rolling bearing unit for wheel support. The volume of the grease is 20% or less of the volume of the grease space in which the grease is enclosed, which is defined by the surface of the sealing material that constitutes the seal ring and the surface of the hub.
A wheel bearing rolling bearing unit according to claim 2. It is a manufacturing method of the rolling bearing unit for wheel support given in any 1 paragraph of Claims 2-3,
After producing the seal ring according to claim 1, the tip end portion of the side lip constituting the seal ring is brought into contact with the axially inner side surface of the rotation-side flange in a state having a tightening margin on the entire circumference. At the same time, the grease is brought into contact with a portion of the inner side surface in the axial direction of the rotation side flange that is closer to a radially inner side than a portion with which the tip portion of the side lip is in contact, and the tip portion of the side lip is Do not touch the parts that are in contact,
A method of manufacturing a wheel-supporting rolling bearing unit characterized by the above.

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