JP2011069422A - Bearing device for wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device for a wheel extending the service life of a bearing by enhancing sealability and durability while suppressing rotary torque of a seal. <P>SOLUTION: The seal 8 consists of: a core metal 11 consisting of a cylindrical fitting part 11a internally fitted in the end of an external member 10 and an inner diameter part 11b bent and formed substantially in a U-shape and extending radially inward; and a seal member 12 having a side lip 12a inclined and extending radially outward, a dust lip 12b inclined and extending radially outward on the inner diameter side, and a grease lip 12c inclined and extending to the inner side of the bearing, in which the side lip 12a and the dust lip 12b are in slide-contact with a base part 4a with an axial margin and the grease lip 12c with a radial margin. Annular recesses 13, 14 with a plurality of annular grooves 13a, 14a in the root part of the side lip 12a and the inner peripheral surface between the dust lip 12b and the grease lip 12c are formed, and are filled with grease. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a wheel bearing device for rotatably supporting a wheel of an automobile or the like, and in particular, a wheel bearing equipped with a seal having a sufficient sealing property even in an environment where a large amount of foreign matter such as rainwater and muddy water exists. It relates to the device.

  Since the wheel bearing device that supports the wheel of the automobile rotatably with respect to the suspension device is in an environment where it is directly exposed to rainwater, muddy water, etc., it is strong so that this rainwater, muddy water, etc. does not enter the inside of the bearing. A seal having a sealing property is attached. In recent years, this type of wheel bearing device used in such a harsh environment has been required to have a longer service life. Damage due to seal failure accounts for more than the bearing life. Accordingly, various wheel bearing devices have been proposed in which the sealability and durability of the seal are improved to improve the bearing life.

  The wheel bearing device shown in FIG. 7 is a typical example of this. The wheel bearing device includes an outer member 56 on the fixed side, a hub ring 53 rotatably supported on the outer member 56 via a ball 57, an outer member 56, and a hub ring 53. And a seal 50 attached to the opening of the annular space formed between the two.

  The seal 50 is configured by adding a seal member 52 to the outer peripheral surface of the core metal 51. The core metal 51 is a hollow cylindrical portion 51a that fits inside the inner peripheral surface of the outer member 56, and a hub from the hollow cylindrical portion 51a. It is comprised from the cyclic | annular bending part 51b bent in the reverse S shape toward the ring | wheel 53. FIG. The seal member 52 is provided with three lips 52a, 52b, 52c extending toward the annular curved surface portion Cs of the hub wheel 53, the surface on the annular curved surface portion Cs side of the outer diameter side lip 52a, and the inner diameter side lip 52b. Overlaying portions P1 and P2 are formed on the surface on the annular curved surface portion Cs side between the innermost lip 52c and the innermost diameter side lip 52c, respectively. At least two of the three lips 52a, 52b, and 52c are in sliding contact with the annular curved surface portion Cs of the hub wheel 53.

  The annular curved surface portion Cs is positioned on the bearing side with respect to the root portion of the wheel mounting flange 54, more specifically, within the bearing E within the arrow range E with respect to the bolt head portion 55a of the hub bolt 55, and continuously along the circumferential direction. Is formed. In this case, at least two lips are always in sliding contact with the annular curved surface portion Cs while the hub wheel 53 and the outer member 56 are relatively rotated or in a stationary state, Leakage of lubricant and entry of foreign matter are prevented.

  Specifically, the built-up part P1 of the outer diameter side lip 52a and the built-up part P2 between the inner diameter side lip 52b and the innermost diameter side lip 52c elastically slidably contact the annular curved surface part Cs. That is, the built-up portion P1 is in sliding contact with the annular curved surface portion Cs by the elastic force of the outer diameter side lip 52a (the force that the outer diameter side lip 52a tries to return in the direction of the annular curved surface portion Cs). 52b and the innermost diameter side lip 52c are slidably contacted with the annular curved surface portion Cs by the elastic force of the inner diameter side lip 52b and the innermost diameter side lip 52c. In this case, the foreign material intrusion is mainly prevented by the built-up portion P1, and the leakage of the lubricant is prevented by the built-up portion P2, and the build-up portion P2 is slidably contacted with the annular curved surface portion Cs. Torque is achieved (for example, refer to Patent Document 1).

  Further, the wheel bearing shown in FIG. 8A has an outer ring 58 having double row outer rolling surfaces 58a, 58a on the inner periphery, and an inner side facing these double row outer rolling surfaces 58a, 58a on the outer periphery. Between a pair of inner rings 59, 59 having a rolling surface 59 a, seals 60, 60 attached to an opening of an annular space formed between the outer ring 58 and the inner ring 59, and between the outer ring 58 and the inner ring 59 Interposed double-row balls 61, 61 and a holder 62 for holding the double-row balls 61, 61 rotatably.

  As shown in (b), the seal 60 has a core composed of a cylindrical surface 63a fitted into the inner peripheral surface of the outer ring 58, and a flange 63b bent radially inward at right angles to the cylindrical surface 63a. It consists of a gold 63 and an elastic seal member 64 baked on the core metal 63. The elastic seal member 64 is bonded to an inner surface 64a formed by the cylindrical surface 63a and the flange portion 63b, and has a plurality of seal lips.

  The plurality of seal lips include an axial lip 65 extending axially outward from a substantially central portion in the radial direction of the elastic seal member 64, and first and second radial lips provided radially inward of the axial lip 65. 66, 67. The axial lip 65 is divided into a main lip 65a having a large diameter at the tip and a sub lip 65b having a small diameter.

  The slinger 68 has a cylindrical portion 68a that is fitted on the outer diameter surface of the inner ring 59, and a flange 68b that is bent radially outward at a right angle to the cylindrical portion 68a. The main lip 65a of the axial lip 65 is the main lip 65a. While being in sliding contact with the flange 68b, the auxiliary lip 65b forms a labyrinth and is not in sliding contact with the flange 68b. The first and second radial lips 66 and 67 are in sliding contact with the cylindrical portion 68a.

  Here, an annular space S is formed by the main lip 65a, the sub lip 65b, and the flange 68b of the slinger 68, and the annular space S is filled with grease G. Thereby, the sealing effect of the seal | sticker 60 can further be improved (for example, refer patent document 2).

JP 2006-200628 A JP-A-2005-330987

  However, among the conventional seals 50 and 60, the former seal 50 prevents entry of foreign matter by the built-up portion P1, and prevents leakage of the lubricant and lowers the torque by the built-up portion P2. The centrifugal force generated by the rotation of the hub wheel 53 may cause the outer diameter side lip 52a and the inner diameter side lip 52b to be deformed radially outward, and the lubricant may flow out to the outside.

  In the latter seal 60, an annular space S is formed by the main lip 65a, the sub lip 65b, and the flange 68b of the slinger 68, and the sealing effect of the seal 60 is improved by the grease G filled in the annular space S. However, in this case, space is limited and design freedom is reduced as compared with a general seal, and the thickness of the main lip 65a and the sub lip 65b is inevitably reduced. There was a risk that the wearability would be reduced.

  The present invention has been made in view of such conventional problems, and provides a wheel bearing device that suppresses the rotational torque of the seal and enhances the sealing performance and durability to extend the life of the bearing. With the goal.

  In order to achieve such an object, the invention according to claim 1 of the present invention includes an outer member in which a double row outer rolling surface is integrally formed on the inner periphery, and an outer rolling of the double row on the outer periphery. An inner member in which a double row inner rolling surface facing the surface is formed, and a double row accommodated between the rolling surfaces of the inner member and the outer member via a retainer so as to roll freely. In the wheel bearing device comprising: a rolling element; and a seal attached to an opening of an annular space formed between the outer member and the inner member, at least one of the seals is: An inner periphery of a base portion of the seal lip, and a core member fitted into the end portion of the outer member; and a seal member integrally bonded to the core metal by vulcanization and having a plurality of seal lips. An annular recess is formed in the surface, and this annular recess is filled with grease.

  Thus, in the wheel bearing device including the seal mounted in the opening of the annular space formed between the outer member and the inner member, at least one of the seals is the outer member. A core metal fitted into the end, and a seal member integrally joined to the metal core by vulcanization and having a plurality of seal lips. An annular recess is formed on the inner peripheral surface of the base of the seal lip. Since this annular recess is filled with grease, the wear resistance of the lip is improved while suppressing the rotational torque, and the lubricating film at the sliding contact portion is maintained for a long period of time to improve the sealing performance. can do.

  Preferably, as in the second aspect of the present invention, if a plurality of independent annular grooves are formed on the inner peripheral surface of the annular recess, the holding force of the grease can be increased.

  According to a third aspect of the present invention, there is provided a hub wheel in which the inner member integrally has a wheel mounting flange for mounting a wheel at one end portion, and a small-diameter step portion is formed on the outer periphery. It comprises at least one inner ring press-fitted into a small-diameter step portion of the hub wheel, the base of the wheel mounting flange is formed in a curved surface having a circular cross section, and the seal is formed on the inner periphery of the end of the outer member. A cylindrical fitting portion to be fitted, a core bar formed from an inner diameter portion bent inward from the fitting portion and extending radially inward, and inclined radially outward. A side lip that extends, a dust lip that extends radially inwardly on the inner diameter side of the side lip, and a grease lip that extends to incline toward the inner side of the bearing. Sliding contact with the base in a predetermined axial direction In addition, the grease lip is constituted by an integral seal comprising a seal member that is slidably contacted with the base portion with a predetermined radial squeezing, and the inner peripheral surface of the base portion of the side lip, the dust lip and the grease lip If the annular recess is formed in the inner peripheral surface, the grease in the grease pocket can be replenished by moving by a small amount to the sliding contact portion of the side lip and the dust lip by centrifugal force during rotation. .

  Preferably, as in the invention described in claim 4, a protrusion protruding radially inward is formed in the vicinity of the annular recess, and a protrusion protruding radially outward at the tip of the dust lip If a grease pocket is formed from the base of the side lip to the outer periphery of the dust lip, it is possible to suppress the movement of grease due to centrifugal force and prevent the grease from flowing out. it can.

  According to a fifth aspect of the present invention, the seal member has a bifurcated radial lip that is slidably contacted with the outer diameter of the inner ring via a predetermined radial shimoshiro. The annular recess may be formed on the peripheral surface.

  Further, as in the invention according to claim 6, the seal member is joined in a range extending from the opening end of the fitting portion of the cored bar to the inner end of the inner diameter portion, and the outer diameter of the seal member is If it is formed slightly larger than the outer diameter of the fitting portion of the core metal and is elastically fitted to the inner periphery of the end of the outer member, it covers the surface portion of the core metal exposed to the outside, Covering the surface portion of the core bar exposed to the outside prevents rusting of the core bar, and improves airtightness so that rainwater, muddy water, and the like do not enter from the fitting portion of the core bar.

  Further, as in the invention according to claim 7, the seal includes a cylindrical fitting portion that is fitted in an end portion of the outer member, and an inner diameter portion that extends radially inward from the fitting portion. And a seal member having a radial lip formed in a bifurcated shape and extending inward in the radial direction on the inner diameter side of the side lip, An annular seal plate, a cylindrical portion disposed opposite to the seal plate, externally fitted to the inner member, and in which the radial lip is slidably contacted via a predetermined radial shimoshiro, and radially outward from the cylindrical portion And a slinger comprising a standing plate portion slidably in contact with the side lip through a predetermined axial direction shimiro, and an inner peripheral surface of the base portion of the side lip, and the grease lip Inner peripheral surface between lips If the are annular recess is formed and can be grease in the grease pocket is grease moved to the sliding contact portion of the side lip and the intermediate lip portions trace by centrifugal force during rotation.

  Further, as in the invention according to claim 8, the seal includes a cylindrical fitting portion fitted in an end portion of the outer member, and an inner diameter portion extending radially inward from the fitting portion. And a pair of side lips extending inclined outward in the radial direction, and a seal member having a grease lip extending inclined inward in the radial direction on the inner diameter side of the side lips. A cylindrical portion that is disposed opposite to the plate, and is externally fitted to the inner member, and the grease lip is slidably contacted through a predetermined radial shimoshiro, and extends radially outward from the cylindrical portion, The side lip is composed of a slinger made up of a standing plate portion that is slidably contacted via a predetermined axial direction shimoshiro, and the annular recess is formed on the inner peripheral surface of the base portion of the pair of side lips. Grease pocket Can grease is grease moved by trace the sliding contact portion of the side lip by centrifugal force during rotation.

  Preferably, as in the invention described in claim 9, if a protrusion protruding radially inward is formed in the vicinity of the annular recess, the movement of grease due to centrifugal force is suppressed, and the grease is exposed to the outside. It can be prevented from flowing out.

  Moreover, if the said metal core is formed from the steel plate which has rust prevention ability like invention of Claim 10, it can prevent reliably that a metal core rusts.

  Further, as in the invention described in claim 11, if the grease is previously applied to the sliding contact portion of each lip of the seal member, the wear resistance of each lip can be improved while suppressing the rotational torque. it can.

  Moreover, if the same grease as the grease enclosed in the bearing is used for the seal as in the invention described in claim 12, it is possible to suppress the consistency change and ensure durability and to reduce the cost. it can.

  If the grease used for the seal is regulated to 60% or less of the space volume between the lips as in the invention described in claim 13, the bearing internal temperature during operation increases. Even if the bearing internal pressure increases, it is possible to effectively prevent the grease from leaking to the outside.

  The wheel bearing device according to the present invention includes an outer member in which a double row outer rolling surface is integrally formed on an inner periphery, and a double row inner rolling that faces the outer rolling surface of the double row on an outer periphery. An inner member having a surface formed thereon, a double row rolling element housed between the rolling surfaces of the inner member and the outer member via a cage, and the outer member; In a wheel bearing device including a seal mounted in an opening of an annular space formed between the inner member and at least one of the seals is fitted into an end of the outer member. And a sealing member integrally bonded to the core by vulcanization and having a plurality of sealing lips, and an annular recess is formed on the inner peripheral surface of the root portion of the sealing lip. Since the annular recess is filled with grease, the wear resistance of the lip is improved while suppressing rotational torque. It is possible to improve the sealability by keeping the lubricating film of the sliding contact portion for a long period of time.

It is a longitudinal section showing one embodiment of a wheel bearing device concerning the present invention. It is a principal part enlarged view which shows one seal part of FIG. It is an expanded sectional view which shows the seal | sticker single-piece | unit of FIG. (A) is a principal part enlarged view which shows the other seal part of FIG. 1, (b) is a principal part enlarged view which shows the state which apply | coated the grease to the seal | sticker of (a). It is a principal part enlarged view which shows the modification of the seal | sticker of Fig.4 (a). It is a principal part enlarged view which shows the other modification of the seal | sticker of Fig.4 (a). It is a longitudinal cross-sectional view which shows the conventional wheel bearing apparatus. (A) is a longitudinal cross-sectional view which shows the other conventional wheel bearing apparatus, (b) is a principal part enlarged view which shows the seal | sticker part of (a).

  An outer member integrally having a vehicle body mounting flange to be attached to the suspension device on the outer periphery, a double row outer rolling surface formed integrally on the inner periphery, and a wheel mounting flange for attaching a wheel to one end And a hub wheel in which one inner rolling surface facing the outer rolling surface of the double row is formed on the outer periphery, and a small-diameter step portion extending in the axial direction from the inner rolling surface, and the hub An inner member formed of an inner ring press-fitted into a small-diameter step portion of the ring and having the other inner rolling surface opposed to the outer rolling surface of the double row on the outer periphery; and the inner member and the outer member A double-row rolling element accommodated between the rolling surfaces via a cage, and a seal attached to an opening of an annular space formed between the outer member and the inner member. The wheel mounting flange has a base with a curved surface with an arc-shaped cross section. The outer seal of the seals is formed into a cylindrical fitting portion that is fitted into the inner periphery of the end of the outer member, and is bent from the fitting portion into a substantially U-shape. A cored bar formed of an inner diameter portion extending radially inward, a side lip extending inclined outward in the radial direction, and a dust lip extending inclined outward in the radial direction on the inner diameter side of the side lip A grease lip extending in an inward direction of the bearing, wherein the side lip and the dust lip are in sliding contact with the base portion with a predetermined axial squeeze, and the grease lip has a predetermined radial shimeoshiro with the base portion. An annular seal having a plurality of independent grooves formed on an inner peripheral surface of the base portion of the side lip and an inner peripheral surface between the dust lip and the grease lip. The place is formed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing an embodiment of a wheel bearing device according to the present invention, FIG. 2 is an enlarged view of a main part showing one seal part of FIG. 1, and FIG. 3 is a single seal of FIG. 4 (a) is an enlarged view of the main part showing the other seal part of FIG. 1, and FIG. 4 (b) is an enlarged view of the main part showing a state where grease is applied to the seal of (a). 5 is a main part enlarged view showing a modification of the seal of FIG. 4A, and FIG. 6 is a main part enlarged view showing another modification of the seal of FIG. 4A. In the following description, the side closer to the outer side of the vehicle when assembled to the vehicle is referred to as the outer side (left side in FIG. 1), and the side closer to the center is referred to as the inner side (right side in FIG. 1).

  This wheel bearing device is for a drive wheel, and includes an inner member 1, an outer member 10, and double-row rolling elements (balls) 6 and 6 accommodated between both members 1, 10, and the third generation. The structure is called. The inner member 1 includes a hub ring 2 and an inner ring 3 that is press-fitted into the hub ring 2 through a predetermined scissors.

  The hub wheel 2 integrally has a wheel mounting flange 4 for attaching a wheel (not shown) to an end portion on the outer side, one (outer side) inner rolling surface 2a on the outer periphery, and this inner rolling. A cylindrical small-diameter step 2b extending in the axial direction from the surface 2a is formed, and a serration (or spline) 2c for torque transmission is formed on the inner periphery. Further, hub bolts 5 are implanted at equal circumferential positions of the wheel mounting flange 4. The inner ring 3 is formed with the other (inner side) inner rolling surface 3a on the outer periphery, and is press-fitted and fixed to the small-diameter step portion 2b of the hub ring 2 via a predetermined shimiro.

  The hub wheel 2 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and includes an inner rolling surface 2a and an inner side of a wheel mounting flange 4 serving as a seal land portion of a seal 8 to be described later. The surface is hardened in the range of 58 to 64 HRC by induction hardening from the base 4a to the small diameter step 2b. On the other hand, the inner ring 3 and the rolling element 6 are made of high carbon chrome steel such as SUJ2, and are hardened in the range of 58 to 64 HRC up to the core portion by quenching.

  The outer member 10 integrally has a vehicle body mounting flange 10b to be attached to a knuckle (not shown) constituting a suspension device on the outer periphery, and the inner rolling surfaces 2a and 3a of the inner member 1 on the inner periphery. Opposing double-row outer rolling surfaces 10a and 10a are integrally formed. Between these rolling surfaces 10a, 2a and 10a, 3a, double row rolling elements 6, 6 are accommodated via a cage 7 so as to be freely rollable. This outer member 10 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and at least double row outer raceway surfaces 10a and 10a are surfaced in the range of 58 to 64HRC by induction hardening. Has been cured. Seals 8 and 9 are attached to the opening of the annular space formed between the outer member 10 and the inner member 1, leakage of the lubricating grease enclosed in the bearing inside, and rainwater from the outside. And dust are prevented from entering the bearing.

  In addition, although the wheel bearing apparatus comprised by the double row angular contact ball bearing which used the ball for the rolling element 6 was illustrated here, this invention is not limited to this, The double row using the tapered roller for the rolling element 6 You may be comprised with the tapered roller bearing. The wheel bearing device according to the present invention is not limited to the illustrated third generation structure, and can be applied to a wheel bearing device having a first generation to a fourth generation structure to which a seal is attached.

  The seal 8 on the outer side of the seals 8 and 9, as shown in an enlarged view in FIG. 2, is an integral type comprising a cored bar 11 and a seal member 12 integrally joined to the cored bar 11 by vulcanization adhesion. It is composed of a seal. The core metal 11 is formed by pressing from a steel plate having rust prevention ability, such as an austenitic stainless steel plate (JIS standard SUS304 type, etc.) or a rust-proof cold rolled steel plate (JIS standard SPCC type, etc.). A cylindrical fitting portion 11a that is formed and fitted into the inner periphery of the end portion of the outer member 10, and an inner diameter that is bent from the fitting portion 11a and formed in a substantially U-shape and extends radially inward. Part 11b.

  On the other hand, the seal member 12 is made of synthetic rubber such as NBR (acrylonitrile-butadiene rubber) and is integrally joined to the core metal 11 by vulcanization adhesion. The seal member 12 includes a side lip 12a extending obliquely outward in the radial direction, a dust lip 12b extending obliquely outward in the radial direction on the inner diameter side of the side lip 12a, and an inward bearing side. And a grease lip 12c extending. The base portion 4a of the wheel mounting flange 4 is formed in a curved surface having an arc-shaped cross section. The side lip 12a and the dust lip 12b are slidably contacted with the base portion 4a with a predetermined axial direction, and the radial lip 12c has a predetermined diameter with the base portion 4a. It is in sliding contact with direction squeezing. In addition to NBR, the material of the seal member 12 includes, for example, HNBR (hydrogenated acrylonitrile-butadiene rubber), EPM, EPDM (ethylene / propylene rubber), etc., which have excellent heat resistance, heat resistance and chemical resistance. Examples thereof include ACM (polyacrylic rubber), FKM (fluororubber), and silicon rubber, which are excellent in properties.

  Here, as shown in an enlarged view in FIG. 3, the seal member 12 is joined to a range extending from the end of the fitting portion 11 a of the core metal 11 to the inner end of the inner diameter portion 11 b and exposed to the outside. 11, the outer diameter of the seal member 12 is formed to be slightly larger than the outer diameter of the fitting portion 11 a and is elastically fitted to the inner periphery of the end portion of the outer member 10. Thereby, while preventing the rusting of the exposed part of the core metal 11, airtightness is improved so that rainwater, muddy water, etc. may not enter from the fitting part 11a of the core metal 11.

  Further, annular recesses 13 and 14 are formed on the inner peripheral surface of the base portion of the side lip 12a and the inner peripheral surface between the dust lip 12b and the grease lip 12c, and project radially inward in the vicinity of the annular recess 13. And a protrusion 16 protruding radially outward from the tip of the dust lip 12b, and a grease pocket 17 extending from the base of the side lip 12a to the outer periphery of the dust lip 12b. Has been.

  In addition, the grease is applied in advance to the sliding contact portions of the side lip 12a, the dust lip 12b, and the grease lip 12c, and the grease pocket 17 is filled with the grease in advance. As a result, the wear resistance of each lip 12a, 12b, 12c is improved while suppressing the rotational torque, and the grease in the grease pocket 17 is brought into contact with the side lip 12a and the dust lip 12b by centrifugal force during rotation. The grease can be replenished by moving a minute amount, and the sealing film can be improved by maintaining the lubricating film in the sliding contact portion over a long period of time.

  Further, in the present embodiment, a plurality of independent annular grooves 13 a and 14 a are formed on the inner peripheral surfaces of the annular recesses 13 and 14. The annular grooves 13a and 14a can increase the holding power of the grease and, in combination with the protrusions 15 and 16, can suppress the movement of the grease due to the centrifugal force and prevent the grease from flowing out.

  The grease used here may be exemplified by wheel bearing grease for automobiles, type 1, consistency 2, 3 (JIS K2220-1993). In this way, by using the same grease that is preliminarily applied to the seal 8 as the grease sealed in the bearing, it is possible to suppress the change in consistency and ensure the durability, and to reduce the cost.

  As shown in FIG. 4A, the inner side seal 9 constitutes a so-called pack seal composed of an annular seal plate 18 and a slinger 19. The seal plate 18 includes a cored bar 20 attached to the outer member 10 and a seal member 21 integrally joined to the cored bar 20 by vulcanization adhesion. The metal core 20 is formed into a substantially L-shaped cross section by pressing from an austenitic stainless steel plate (JIS standard SUS304 type or the like) or a rust-proof cold rolled steel plate (JIS standard SPCC type or the like). The outer member 10 has a cylindrical fitting portion 20a that is press-fitted into the inner periphery of the inner side end portion, and an inner diameter portion 20b that extends radially inward from the fitting portion 20a.

  The seal member 21 is made of synthetic rubber such as NBR, and is joined to a range extending from the end of the fitting portion 20a of the core metal 20 to the inner end of the inner diameter portion 20b, covering the open end of the core metal 20, The outer diameter of the seal member 21 is formed to be slightly larger than the outer diameter of the fitting portion 20 a and is elastically fitted to the inner periphery of the end portion of the outer member 10. Thereby, airtightness is improved so that rainwater, muddy water, etc. may not enter the inside of the bearing from the fitting portion 20a of the cored bar 20. And it has the side lip 21a which inclines and extends in the radial direction outward, the grease lip 21c and the intermediate lip 21b formed in a bifurcated shape.

  On the other hand, the slinger 19 includes a cylindrical portion 19a that is press-fitted into the outer diameter of the inner ring 3, and a standing plate portion 19b that extends radially outward from the cylindrical portion 19a. The side lip 21a of the seal member 21 is in sliding contact with the upright plate portion 19b via a predetermined axial shimiro, and the grease lip 21c and the intermediate lip 21b are in sliding contact with the cylindrical portion 19a via a predetermined radial shimillo. Yes. Further, the outer edge of the standing plate portion 19b in the slinger 19 is opposed to the end portion of the seal member 21 through a slight radial clearance to form a labyrinth seal 22.

  The slinger 19 is made of a ferritic stainless steel plate (JIS standard SUS430 or the like), an austenitic stainless steel plate (JIS standard SUS304 type or the like), or a rust-proof cold rolled steel plate (JIS standard SPCC). The cross section is formed in a substantially L shape by press working from the system. Thereby, even if the slinger 19 is exposed to rain water, muddy water, or the like, and even if rain water, muddy water, or the like adheres to the fitting portion with the inner ring 3, rusting can be prevented.

  Here, annular recesses 23 and 24 are formed on the inner peripheral surface of the base portion of the side lip 21a and the inner peripheral surface between the intermediate lip 21b and the grease lip 21c, thereby forming a grease pocket. The grease pocket is filled with grease in advance. As a result, the grease in the annular recess 23 can move to the side lip 21a by a small amount by centrifugal force during rotation to replenish the grease, and the grease in the annular recess 24 can be supplied to the intermediate lip 21b and the grease lip 21c. The lubricating film at the sliding contact portion can be maintained to improve wear resistance and sealing performance.

  It should be noted that as much grease as possible is advantageous in terms of sealing durability, but here, as shown in FIG. 4B, the space volume extending from the side lip 21a to the grease lip 21c is 60%. % Or less. Thereby, it is possible to effectively prevent the grease from leaking to the outside even when the bearing internal pressure increases as the bearing internal temperature increases during operation.

  The seal 25 shown in FIG. 5 basically differs in the configuration of the seal 9 (FIG. 4) and the seal member 27 described above. The seal 25 constitutes a pack seal including an annular seal plate 26 and a slinger 19. The seal plate 26 includes a metal core 20 that is elastically fitted to the inner periphery of the end of the outer member 10 and a seal member 27 that is integrally joined to the metal core 20 by vulcanization adhesion. The seal member 27 has a pair of side lips 27a and 27b extending obliquely outward in the radial direction and a grease lip 27c.

  The side lips 27a and 27b of the seal member 27 are in sliding contact with the upright plate portion 19b via a predetermined axial shimiro, and the grease lip 27c is in sliding contact with the cylindrical portion 19a via a predetermined radial shimillo. Further, the outer edge of the standing plate portion 19b in the slinger 19 is opposed to the end portion of the seal member 27 through a slight radial clearance to form a labyrinth seal 22.

  Here, annular recesses 28 and 29 are formed on the inner peripheral surfaces of the base portions of the side lips 27a and 27b, and a plurality of independent annular grooves 28a and 29a are formed on the inner peripheral surfaces of the annular recesses 28 and 29. ing. The annular groove 28a, 29a can increase the holding force of the grease. Further, protrusions 30 and 31 protruding radially inward are formed in the vicinity of the annular recesses 28 and 29 to constitute a grease pocket. The grease pocket is filled with grease in advance. As a result, the grease in the annular recesses 28 and 29 can be replenished by a small amount to the side lips 27a and 27b by centrifugal force during rotation, and the grease can be replenished. And the sealing performance can be improved.

  The seal 32 shown in FIG. 6 is constituted by an integral seal comprising a cored bar 33 and a seal member 34 integrally joined to the cored bar 33 by vulcanization adhesion. The core metal 33 is formed by pressing from a steel plate having rust prevention ability such as an austenitic stainless steel plate (JIS standard SUS304 type or the like) or a rust-proof cold rolled steel plate (JIS standard SPCC type or the like). A cylindrical fitting portion 33a that is formed and is fitted into the inner periphery of the inner side end of the outer member 10, and is bent from the fitting portion 333a to form a substantially U-shape. And an inner diameter portion 33b extending in the direction.

  On the other hand, the seal member 34 is made of synthetic rubber such as NBR and is integrally joined to the core metal 33 by vulcanization adhesion. The seal member 34 includes a bifurcated dust lip 34a and a grease lip 34b that are in sliding contact with the outer diameter of the inner ring 3 via a predetermined radial shimiro. Here, the seal member 34 is joined in a range extending from the end portion of the fitting portion 33a of the core bar 33 to the inner end portion of the inner diameter portion 33b, covers the surface portion of the core bar 33 exposed to the outside, and seal member The outer diameter of 34 is formed to be slightly larger than the outer diameter of the fitting portion 33 a and is elastically fitted to the inner periphery of the end portion of the outer member 10. This prevents rusting of the exposed part of the cored bar 33 and enhances airtightness so that rainwater, muddy water or the like does not enter from the fitting part 33a of the cored bar 33.

  Here, an annular recess 35 is formed on the inner peripheral surface between the dust lip 34a and the grease lip 34b, and a plurality of independent annular grooves 35a are formed on the inner peripheral surface of the annular recess 35, so that the grease pockets are formed. It is configured. The annular recess 35 is filled with grease in advance. Thus, as in the above-described embodiment, the wear resistance of each lip 34a, 34b is improved while suppressing rotational torque, and the sealing film is improved by maintaining the lubricating film at the sliding contact portion over a long period of time. be able to.

  The embodiment of the present invention has been described above, but the present invention is not limited to such an embodiment, and is merely an example. Of course, the scope of the present invention is indicated by the description of the scope of claims, and further, the equivalent meanings described in the scope of claims and all modifications within the scope of the scope of the present invention are included. Including.

  The wheel bearing device according to the present invention can be applied to a wheel bearing device having a first generation to a fourth generation structure in which a seal including a metal core and a seal member joined to the metal core is mounted.

DESCRIPTION OF SYMBOLS 1 Inner member 2 Hub wheel 2a, 3a Inner rolling surface 2b Small diameter step part 2c Serration 3 Inner ring 4 Wheel mounting flange 4a Base part of the inner side of a wheel mounting flange 5 Hub bolt 6 Rolling body 7 Cage 8 Outer side seal 9, 25, 32 Inner side seal 10 Outer member 10a Outer rolling surface 10b Car body mounting flange 11, 20, 33 Core metal 11a, 20a, 33a Fitting portion 11b, 20b, 33b Inner diameter portion 12, 21, 27, 34 Seal Member 12a, 21a, 27a, 27b Side lip 12b, 34a Dustrip 12c, 21c, 27c, 34b Grease lip 13, 14, 23, 24, 28, 29, 35 Annular recess 13a, 14a, 28a, 29a, 35a Annular Groove 15, 16, 30, 31 Protrusion 17 Grease pocket 18 Seal plate 19 Slinger 19a Cylindrical portion 19b Standing plate portion 21b Intermediate lip 22 Labyrinth seal 50, 60 Seal 51, 63 Core metal 51a Hollow cylindrical portion 51b Annular bent portion 52 Seal member 52a Outer diameter side lip 52b Inner diameter side lip 52c Outermost diameter side lip 53 Hub wheel 54 Wheel mounting flange 55 Hub bolt 55a Bolt head 56 Outer member 57, 61 Ball 58 Outer ring 58a Outer rolling surface 59 Inner ring 59a Inner rolling surface 62 Cage 63a Cylindrical surface 63b Ridge portion 64 Elastic seal member 64a Inner side surface 65 Axial lip 65a main lip 65b sub lip 66 first radial lip 67 second radial lip 68 slinger 68a cylindrical portion 68b flange Cs annular curved surface portion G grease P1, P2 build-up portion S annular space

Claims (13)

An outer member in which a double row outer rolling surface is integrally formed on the inner periphery;
An inner member in which a double row inner rolling surface facing the outer row rolling surface of the double row is formed on the outer periphery;
A double row rolling element housed between the rolling surfaces of the inner member and the outer member so as to roll freely through a cage;
In a wheel bearing device comprising a seal mounted in an opening of an annular space formed between the outer member and the inner member,
At least one of the seals includes a core metal fitted into an end portion of the outer member, and a seal member integrally bonded to the core metal by vulcanization and having a plurality of seal lips. An annular recess is formed in the inner peripheral surface of the base portion of the seal lip, and grease is filled in the annular recess.   The wheel bearing device according to claim 1, wherein a plurality of independent annular grooves are formed on an inner peripheral surface of the annular recess.   The inner member integrally has a wheel mounting flange for mounting a wheel at one end, a hub wheel having a small-diameter step formed on the outer periphery, and at least one press-fitted into the small-diameter step of the hub wheel An inner ring, and a base part of the wheel mounting flange is formed in a curved surface having an arc-shaped cross section, and the seal is fitted into a cylindrical fitting part fitted into the inner periphery of the end part of the outer member, and this fitting It is formed in a substantially U shape by bending from the joint part, a cored bar consisting of an inner diameter part extending radially inward, a side lip extending obliquely outward in the radial direction, and an inner diameter side of this side lip, A dust lip extending obliquely outward in the radial direction and a grease lip extending inclined toward the inner side of the bearing, the side lip and the dust lip are in sliding contact with the base portion with a predetermined axial squeezing force, and Grease lip And a seal member that is slidably contacted with a predetermined radial squeezing portion, and is formed on the inner peripheral surface of the base portion of the side lip and on the inner peripheral surface between the dust lip and the grease lip. The wheel bearing device according to claim 1 or 2, wherein an annular recess is formed.   A protrusion projecting radially inward is formed in the vicinity of the annular recess, and a protrusion projecting radially outward is formed at the tip of the dust lip. The wheel bearing device according to claim 3, wherein a grease pocket is formed along the outer periphery.   The seal member has a bifurcated radial lip that is slidably contacted with an outer diameter of the inner ring via a predetermined radial nip, and the annular recess is formed on an inner peripheral surface between the radial lips. Item 3. A wheel bearing device according to Item 1 or 2.   The seal member is joined in a range extending from the open end of the fitting portion of the metal core to the inner end of the inner diameter portion, and the outer diameter of the seal member is slightly smaller than the outer diameter of the fitting portion of the metal core. The wheel bearing device according to any one of claims 1 to 5, wherein the wheel bearing device is formed in a large diameter and elastically fitted to an inner periphery of an end portion of the outer member.   The seal is inclined radially outwardly with a metal core comprising a cylindrical fitting part fitted into the end of the outer member and an inner diameter part extending radially inward from the fitting part. A ring-shaped seal plate comprising a side lip extending inward and a seal member having a radial lip formed in a bifurcated shape and extending radially inward on the inner diameter side of the side lip, and opposed to the seal plate A cylindrical portion that is disposed and externally fitted to the inward member, and the radial lip is slidably contacted via a predetermined radial shim Shiro, and extends radially outward from the cylindrical portion, and the side lip is a predetermined axial shimiro And a slinger formed of a standing plate portion that is slidably contacted with each other, and the annular recess is formed on the inner peripheral surface of the base portion of the side lip and the inner peripheral surface between the grease lip and the intermediate lip. Claims formed Or wheel bearing device according to 2.   The seal is inclined radially outwardly with a metal core comprising a cylindrical fitting part fitted into the end of the outer member and an inner diameter part extending radially inward from the fitting part. An annular seal plate comprising a pair of side lips extending inward and a seal member having a grease lip extending inward in the radial direction on the inner diameter side of the side lips, and disposed opposite to the seal plate, A cylindrical portion that is externally fitted to the lateral member, and the grease lip is slidably contacted via a predetermined radial nip, and extends radially outward from the cylindrical portion, and the side lip is slidably contacted via a predetermined axial nip The wheel bearing device according to claim 1, wherein the annular recess is formed on an inner peripheral surface of a root portion of the pair of side lips.   The wheel bearing device according to claim 7 or 8, wherein a protrusion protruding radially inward is formed in the vicinity of the annular recess.   The wheel bearing device according to any one of claims 1 to 9, wherein the core metal is formed of a steel plate having anti-rust ability.   The wheel bearing device according to any one of claims 1 to 10, wherein grease is previously applied to a sliding contact portion of each lip of the seal member.   The wheel bearing device according to claim 11, wherein the same grease as the grease sealed in the bearing is used for the seal.   The wheel bearing device according to claim 12, wherein grease used for the seal is regulated to 60% or less of a space volume between the lips.

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