JP2009180366A - Wheel bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wheel bearing device achieved in a longer operating life of a bearing by improving the sealing performance and durability of a seal. <P>SOLUTION: A hub ring 2 has an integrated wheel mounting flange 4 at one end, and an inside rolling face 2a formed on the outer periphery. On an inner side of the wheel mounting flange 4, a base 4a is formed on a sectionally circular curved face. The seal 8 on the outer side is composed of a core metal 11 internally fitted to the end of an outward member 10, and a seal member 12 integrally bonded to the core metal 11 with cure adhesion and having a side lip 12a in slide contact with the base 4a via an interference port and a pair of radial lips 12b, 12c. On the surface of the base 4a, a coat layer 13 having a ceramic layer 13b is formed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wheel bearing device for rotatably supporting a wheel of an automobile or the like, and more particularly, a wheel equipped with a seal having a sufficient sealing property for a long period of time even in an environment where a large amount of foreign matter such as rainwater and muddy water exists. The present invention relates to a bearing 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. This is a wheel bearing device on the drive wheel side, and integrally has a vehicle body mounting flange 51b attached to the vehicle body (not shown) on the outer periphery, and double row outer rolling surfaces 51a and 51a are formed on the inner periphery. The outer member 51 and the wheel mounting flange 53 to which a wheel (not shown) is attached at one end are integrally formed, and one inward rolling facing the double row outer rolling surfaces 51a, 51a is provided on the outer periphery. A running surface 52a, a cylindrical small diameter step portion 52b extending in the axial direction from the inner rolling surface 52a, and a hub wheel 52 having a torque transmission serration 52c formed on the inner periphery, and the small diameter step portion 52b And an inner ring 55 that is press-fitted and has the other inner rolling surface 55a formed on the outer periphery. A hub bolt 54 for mounting a wheel (not shown) is implanted at a circumferentially equidistant position of the wheel mounting flange 53 of the hub wheel 52.

  A double row of balls 56 is accommodated by a cage 57 between the double row outer raceway surfaces 51a and 51a and the inner raceway surfaces 52a and 55a opposite to each other. Seals 59 and 60 are respectively attached to the openings of the annular space formed between the inner member 58 formed of the hub ring 52 and the inner ring 55 and the outer member 51, and sealed inside the bearing. This prevents leakage of lubricating grease and intrusion of rainwater and muddy water into the bearing from the outside.

  Of these seals 59, 60, the seal 60 mounted between the outer member 51 and the inner ring 55 is fitted into the outer member 51 serving as the stationary raceway, as shown in FIG. Are fitted on an annular seal plate 63 composed of a cored bar 61 formed on the cored bar 61 and a sealing member 62 vulcanized and bonded to the cored bar 61, and an inner ring 55 serving as a rotating raceway. A cylindrical portion 64a formed in a letter shape and press-fitted into the outer diameter of the inner ring 55, and a slinger 64 including a standing plate portion 64b extending radially outward from the cylindrical portion 64a are provided.

  The seal member 62 is made of an elastic member such as rubber, and includes three seal lips, that is, a side lip 62a, a grease lip 62b, and an intermediate lip 62c, and the end edge of the side lip 62a is the inner surface of the standing plate portion 64b of the slinger 64. The tip edges of the remaining grease lip 62b and intermediate lip 62c are in sliding contact with the cylindrical portion 64a of the slinger 64. The seal plate 63 and the tip of the standing plate portion 64b of the slinger 64 are opposed to each other through a slight radial clearance, and the labyrinth seal 65 is configured up to this clearance.

Further, a friction reducing film 66 for reducing the sliding resistance of each lip is formed on the entire surface of the slinger 64. The friction reducing coating 66 is formed of a polyamide such as 6 nylon or 12 nylon, a synthetic resin having low friction such as polytetrafluoroethylene or polyethylene, or a diamond-like carbon film. As a result, the sliding resistance is reduced without reducing the contact pressure of each lip, and the rotational torque is reduced. Further, lip wear is reduced by the low friction between the slinger 64 and each lip, heat generation at the lip sliding portion is suppressed, and durability of the seal 60 is improved (see, for example, Patent Document 1).
JP 2002-227856 A

  However, in such a conventional seal 60, if the friction reducing coating 66 formed on the entire surface of the slinger 64 is made of a synthetic resin, the sliding resistance is reduced, but it wears in the long term and is not reliable. . On the other hand, if the friction reducing coating 66 is a diamond-like carbon film, it cannot be said that the binding force to the slinger 64 is sufficient, and there is a risk of peeling in the long term, resulting in insufficient reliability.

  The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide a wheel bearing device in which the sealing performance and durability of a seal are enhanced to extend the life of the bearing.

  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. A rolling bearing and a seal mounted in an opening of an annular space formed between the outer member and the inner member, wherein the seal is an end of the outer member. A core metal fitted into the core, a seal member integrally joined to the metal core by vulcanization adhesion, and having a plurality of seal lips, and a coating provided with a ceramic layer on the sliding surface of the seal lip A layer is formed.

  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, the seal is fitted into the end of the outer member. And a sealing member integrally bonded to the core by vulcanization and having a plurality of seal lips, and a coating layer having a ceramic layer is formed on the sliding surface of the seal lip. Therefore, the corrosive substance does not enter the base material base, the corrosion resistance can be improved, the sliding resistance of each lip is reduced, the rotational torque is reduced, and the sliding contact surface and each lip are It is possible to provide a wheel bearing device in which lip wear is reduced due to low friction, heat generation at the lip sliding portion is suppressed, seal sealing performance and durability are improved, and the life of the bearing is extended. Note that the coating layer may have a single-layer structure including only a ceramic layer, or a multilayer structure including a plurality of layers such as a ceramic layer and a metal layer.

  Preferably, as in the invention described in claim 2, if the covering layer has a laminated layer structure including a metal layer and a ceramic layer, adhesion to a metal can be enhanced.

  Further, as in the invention described in claim 3, if the coating layer is a sprayed layer and a sealing process is performed after the spraying is completed, it is possible to prevent moisture from entering the pores.

  According to a fourth aspect of the present invention, the seal is composed of an integrated seal having a plurality of seal lips that are slidably contacted with the outer peripheral surface of the inner member via a shimoshiro. The coating layer may be formed on the outer peripheral surface.

  According to a fifth aspect of the present invention, the inner member integrally has a wheel mounting flange for mounting a wheel at one end, and faces one of the double-row outer rolling surfaces on the outer periphery. And a hub ring formed with a small-diameter step portion extending in the axial direction from the inner rolling surface, and a small-diameter step portion of the hub ring is press-fitted and fixed to the outer periphery via a predetermined shimiro, The inner ring formed with an inner rolling surface facing the other of the outer rolling surfaces of the row, the base on the inner side of the wheel mounting flange is formed in a curved surface with an arc-shaped cross section, and the seal, The base may have a side lip that is in sliding contact with the base through a shimillo, and the coating layer may be formed on the surface of the base.

  According to a sixth aspect of the present invention, the seal is disposed opposite to the annular seal plate having a seal member composed of a side lip and a radial lip, and is fitted on the inner member. And a pack seal comprising a cylindrical portion to which the radial lip is slidably contacted, and a slinger consisting of a standing plate portion extending radially outward from the cylindrical portion and to which the side lip is slidably contacted, The coating layer may be formed on the surface of the slinger that is in sliding contact with the seal lips.

  Preferably, if the coating layer is formed on the entire surface of the slinger as in the seventh aspect of the invention, the corrosion resistance of the slinger itself can be improved, and the sealing performance and durability of the seal can be further improved. it can.

  Further, as in the invention described in claim 8, if the coating layer is formed by the aerosol position method, the corrosive substance does not enter the base material, and the corrosion resistance can be improved. In addition, the sliding resistance of each lip is reduced, the rotational torque is reduced, and the lip wear is reduced by the low friction between the sliding contact surface and each lip, and the heat generation of the lip sliding contact surface is suppressed and the sealing performance of the seal is reduced. Thus, it is possible to provide a wheel bearing device in which durability is increased and the bearing life is extended.

  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; A wheel bearing device including a seal mounted in an opening of an annular space formed between the inner member and a core metal fitted into an end of the outer member; Since this core metal is integrally bonded by vulcanization adhesion and has a seal member having a plurality of seal lips, a coating layer having a ceramic layer is formed on the sliding contact surface of the seal lip. Does not penetrate into the base material, can improve the corrosion resistance, and the sliding resistance of each lip The rotational torque is reduced, and the friction between the slidable contact surface and each lip reduces lip wear, and heat generation at the lip sliding part is suppressed to improve the sealing performance and durability of the seal. It is possible to provide a wheel bearing device with a long life.

  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. And the wheel mounting flange has a base portion on the inner side having a circular arc in cross section. The outer seal of the seals is integrally joined to the end of the outer member, and the core is integrally joined to the core by vulcanization adhesion, A covering member having a laminated structure including a metal layer and a ceramic layer is formed on the surface of the base portion, which includes a sealing member having a side lip and a pair of radial lips that are in sliding contact with each other via a shimoshiro.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a first embodiment of a wheel bearing device according to the present invention, FIG. 2A is an enlarged view of a main part showing one seal portion of FIG. 1, and FIG. FIG. 3 is a schematic view showing the coating layer of (a), FIG. 3 is an enlarged view of the main part showing the other seal part of FIG. 1, and FIG. 4 is an enlarged view of the main part showing a modification of FIG. 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, and leakage of the lubricating grease sealed inside the bearing to the outside, rainwater and It prevents dust and the like from entering the bearing.

  In addition, although the double row angular contact ball bearing which used the ball for the rolling element 6 was illustrated here, this invention is not restricted to this, The double row tapered roller bearing which uses the tapered roller for the rolling element 6 may be sufficient. . 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 includes, as shown in an enlarged view in FIG. 2A, a cored bar 11 and a seal member 12 integrally joined to the cored bar 11 by vulcanization adhesion. It is comprised by the integrated seal which becomes. The core 11 is formed by pressing a cold-rolled steel plate (JIS standard SPCC system or the like), and is fitted into a cylindrical fitting portion 11a fitted into the inner periphery of the end of the outer member 10, and this fitting And an inner diameter part 11b formed by bending from the joint part 11a and extending radially inward.

  On the other hand, the seal member 12 is made of synthetic rubber such as nitrile rubber and is integrally joined to the core metal 11 by vulcanization adhesion. The seal member 12 includes a side lip 12a formed to be inclined outward in the radial direction, and a pair of radial lips 12b and 12c formed in a bifurcated shape. The base portion 4a of the wheel mounting flange 4 is formed in a curved surface having an arcuate cross section. The side lip 12a is in sliding contact with the base portion 4a with a predetermined axial direction, and the radial lips 12b and 12c are in sliding contact with a predetermined radial direction. ing.

  Here, the coating layer 13 is formed on the surface of the base portion 4a which becomes the sliding contact surface of the side lip 12a and the radial lips 12b and 12c. As schematically shown in FIG. 2B, the covering layer 13 has a three-layer structure in which the innermost layer is a metal layer 13a, the intermediate layer is a ceramic layer 13b, and the outermost layer is a metal layer 13c. The metal layers 13a and 13c and the ceramic layer 13b are all sprayed layers, and the outermost metal layer 13c is sprayed to a thickness including a grinding allowance, and after spraying, the surface is predetermined by machining such as grinding. It is formed to the dimension.

  Thermal spraying is to form a surface film by melting a material to be sprayed at an ultra-high temperature (for example, powder or rod) and colliding with a workpiece by a jet jet. Appropriate thermal spraying conditions are set using a thermal spraying device that can obtain a relatively high-speed jet and ultra-high temperature. Since each metal layer 13a, 13c and ceramic layer 13b made of this thermal spray layer has fine pores, after the completion of thermal spraying, sealing treatment is performed so that moisture does not enter the pores. This sealing treatment is performed with a resin, an adhesive, or an inorganic fine powder having good permeability.

As the ceramic material for the ceramic layer 13b, alumina _{(Al 2 O} 3), gray alumina, titanium oxide _(TiO 2), can be exemplified metal oxides such as chromium oxide _(Cr 2 _{O 3)} . On the other hand, Al, Ni, Cr, Fe etc. can be illustrated as a material of the metal layers 13a and 13c. The metal layers 13a and 13c are preferably made of a relatively soft material having a hardness after spraying of Hv 450 or less, preferably Hv 300 or less.

  The covering layer 13 is not only a single layer structure composed of only the ceramic layer 13b, or a three-layer structure composed of the metal layer 13a as the innermost layer, the ceramic layer 13b as the intermediate layer, and the metal layer 13c as the outermost layer. A two-layer structure in which the metal layer 13c is omitted, that is, a two-layer structure in which the inner layer includes the metal layer 13a and the outer layer includes the ceramic layer 13b may be employed.

  Further, since the coating layer 13 is formed on the surface of the base portion 4a serving as the sliding contact surface, the sliding resistance of each lip is reduced, the rotational torque is reduced, and the lip is reduced due to the low friction between the base portion 4a and each lip. It is possible to provide a wheel bearing device in which wear is reduced, heat generation at the lip sliding portion is suppressed, the sealing performance and durability of the seal 8 are improved, and the bearing life is extended.

  The formation of the ceramic layer 13 by thermal spraying has been described above, but the ceramic layer 13 can also be formed by the aerosol position method (hereinafter referred to as AD method I. This AD method is a method in which fine particles of a raw material ceramic are dispersed in a gas. The aerosol is sprayed by an aerosol spray nozzle toward the coating formation portion, the aerosol is collided with the surface of the substrate at a high speed, and a coating composed of fine particle constituent materials is formed on the substrate.

  The ceramic fine particles are pulverized by collision to form a clean new surface and cause low-temperature bonding, so that bonding of the fine particles can be realized at room temperature. Further, in the aerosol, the ceramic fine particles maintain a dispersed state, and the coating obtained by the thermal spraying method is porous, whereas the coating obtained by the AD method becomes an extremely dense ceramic coating 13. For this reason, since the base 4a exposed to the corrosive substance is protected by the ceramic coating 13 having no pores through which the corrosive substance can permeate, the corrosive substance does not enter the base material, and the corrosion resistance can be improved. it can.

  Further, since the ceramic coating 13 is formed on the surface of the base portion 4a serving as the sliding contact surface, the sliding resistance of each lip is reduced, the rotational torque is reduced, and the lip is reduced due to the low friction between the base portion 4a and each lip. It is possible to provide a wheel bearing device in which wear is reduced, heat generation at the lip sliding portion is suppressed, the sealing performance and durability of the seal 8 are improved, and the bearing life is extended.

  Examples of the ceramic fine particles used as an aerosol raw material for forming the ceramic coating 13 by the AD method include oxide ceramic fine particles such as alumina, zirconia, and titania having good corrosion resistance. Among these, alumina fine particles having a small true specific gravity and being easily aerosolized are preferable. In the present embodiment, an alumina fine particle having an average particle diameter in the range of 0.01 μm to 2 μm is used. If the average particle size is less than 0.01 μm, it is easy to adhere and aerosolization is difficult, and if it exceeds 2 μm, the film itself does not grow, so that film formation by the AD method cannot be performed.

  The particle size adjustment method of alumina fine particles includes alkoxide method and colloid method, pyrolysis method of ammonium alum, ammonium aluminum carbonate pyrolysis method, improved buyer method, chemical method of ethylene chlorohydrin method, gas evaporation method A method of heating fine particles of several tens of nanometers or less produced using a physical method such as sputtering, aluminum underwater spark discharge, and agglomerating them into secondary particles having a particle diameter of about several hundreds of nanometers. Can be mentioned. In order to satisfactorily form a film, it is preferable to form a crack in advance using a pulverizer such as a ball mill or a jet mill so that the alumina fine particles are easily pulverized at the time of collision with the substrate.

  As shown in an enlarged view in FIG. 3, the inner seal 9 constitutes a so-called pack seal including an annular seal plate 14 and a slinger 15. The seal plate 14 includes a cored bar 16 attached to the outer member 10 and a seal member 17 integrally joined to the cored bar 16 by vulcanization adhesion. The metal core 16 is formed in a substantially L-shaped cross section by press working from a cold rolled steel plate (JIS standard SPCC system or the like), and is a cylindrical fitting portion that is press-fitted into the inner periphery of the end of the outer member 10. 16a and an inner diameter portion 16b extending radially inward from the fitting portion 16a. The seal member 17 is made of an elastic member such as a synthetic rubber, and includes a side lip 17a extending obliquely outward in the radial direction and a pair of radial lips 17b and 17c formed in a bifurcated shape.

  On the other hand, the slinger 15 includes a cylindrical portion 15a that is press-fitted into the outer diameter of the inner ring 3, and a standing plate portion 15b that extends radially outward from the cylindrical portion 15a. The side lip 17a of the seal member 17 is in sliding contact with the upright plate portion 15b, and the pair of radial lips 17b and 17c are in sliding contact with the cylindrical portion 15a. Further, the outer edge of the standing plate portion 15 b in the slinger 15 faces the seal plate 14 through a slight radial clearance to constitute a labyrinth seal 18.

  The slinger 15 is a ferritic stainless steel plate (JIS standard SUS430 or the like), an austenitic stainless steel plate (JIS standard SUS304 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 15 is exposed to rain water, muddy water, or the like, or even if rain water, muddy water or the like enters the fitting portion with the inner ring 3, the slinger 15 can be prevented from rusting.

  Here, the coating layer 19 is formed on the inner surface of the slinger 15 which is the sliding surface of the side lip 17a and the radial lips 17b and 17c. The covering layer 19 has a two-layer structure in which an inner layer is a metal layer and an outer layer is a ceramic layer. As a result, like the outer seal 8 described above, the sliding resistance of each lip is reduced, the rotational torque is reduced, and the lip wear is reduced by the low friction between the slinger 15 and each lip. Heat generation is suppressed, and the sealing performance and durability of the seal 9 can be improved.

  FIG. 4 shows a modification. This seal 20 basically differs from the above-described seal 9 only in the configuration of the slinger, and other parts having the same parts or the same functions are denoted by the same reference numerals and detailed description thereof is omitted.

  The seal 20 includes an annular seal plate 14 and a slinger 21. The slinger 21 includes a cylindrical portion 21a that is press-fitted into the outer diameter of the inner ring 3, and a standing plate portion 21b that extends radially outward from the cylindrical portion 21a. The covering layer 19 is formed on the entire surface of the slinger 21 including the inner surface which is the sliding surface of the side lip 17a and the radial lips 17b and 17c. As a result, the corrosion resistance of the slinger 21 is further improved. Like the seals 8 and 9, the sliding resistance of each lip is reduced, the rotational torque is reduced, and the lip wear is caused by the low friction between the slinger 21 and each lip. And the heat generation of the lip sliding portion is suppressed, and the sealing performance and durability of the seal 20 can be enhanced.

  FIG. 5 is a longitudinal sectional view showing a second embodiment of the wheel bearing device according to the present invention, and FIG. 6 is an enlarged view of a main part showing one seal portion of FIG. In addition, the same code | symbol is attached | subjected to the component same site | part or the site | part which has the same function as embodiment mentioned above, and detailed description is abbreviate | omitted.

  This wheel bearing device is referred to as a first generation, and is accommodated in a rollable manner via a cage 7 between an inner member 23 and an outer member 24 composed of a pair of inner rings 22 and 3, and both members 23 and 24. A double-row angular contact ball bearing of a back-to-back type is provided.

  The outer member 24 is made of high carbon chrome steel such as SUJ2, and is hardened in the range of 58 to 64 HRC up to the core part by quenching. Seals 25 and 9 are attached to the opening of the annular space formed between the outer member 24 and the inner member 23, and leakage of the lubricating grease enclosed in the bearing to the outside and from the outside It prevents rainwater and dust from entering the bearing.

  As shown in an enlarged view in FIG. 6, the outer side seal 25 is constituted by an integral seal including a cored bar 26 and a seal member 27 integrally joined to the cored bar 25 by vulcanization adhesion. Yes. The core metal 26 is formed by pressing a cold-rolled steel plate (JIS standard SPCC system or the like), and is fitted into a cylindrical fitting portion 26a fitted into the inner periphery of the end portion of the outer member 24. An inner diameter portion 26b formed by bending from the joint portion 26a and extending radially inward is provided.

  On the other hand, the seal member 27 is made of synthetic rubber such as nitrile rubber and is integrally joined to the cored bar 26 by vulcanization adhesion. The seal member 27 has a pair of radial lips 27a and 27b formed in a bifurcated shape, and the radial lips 27a and 27b are in sliding contact with the outer diameter surface 22a of the inner ring 22 with a predetermined radial direction.

  Here, the coating layer 28 is formed on the surface of the outer diameter surface 22a of the inner ring 22 which is the sliding contact surface of the radial lips 27a and 27b. The coating layer 28 has a two-layer structure in which an inner layer is a metal layer and an outer layer is a ceramic layer. Thereby, the corrosion resistance of the sliding contact surface is improved, and the sliding resistance of each lip is reduced, the rotational torque is reduced, and the low friction between the outer diameter surface 22a of the inner ring 22 and each lip, as in the embodiment described above. Thus, lip wear is reduced, heat generation at the lip sliding portion is suppressed, and the sealing performance and durability of the seal 25 can be improved.

  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, and various modifications can be made without departing from the scope of the present invention. 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 is attached to an opening of an annular space.

It is a longitudinal section showing a 1st embodiment of a bearing device for wheels concerning the present invention. (A) is a principal part enlarged view which shows one seal | sticker part of FIG. (B) is a schematic diagram which shows the coating layer of (a). It is a principal part enlarged view which shows the other seal part of FIG. It is a principal part enlarged view which shows the modification of FIG. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the wheel bearing apparatus which concerns on this invention. It is a principal part enlarged view which shows one seal | sticker part of FIG. It is a longitudinal cross-sectional view which shows the conventional wheel bearing apparatus. It is a principal part enlarged view of FIG.

Explanation of symbols

1, 23 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inner member 2 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・.... Hub wheels 2a, 3a ..... Inner rolling surface 2b ...・ ・ ・ ・ ・ Small diameter step 2c ・ ・ ・ ・ ・ ・ ・ ・ Serrations 3, 22 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inner ring 4 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Wheel mounting flange 4a ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Base 5 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Hub Bolt 6 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Rolling element 7 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Retainer 8, 25 ・ ・ ・ ・ ・ ・...・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Outer side seals 9, 20 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inner side seals 10, 24 ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Outer member 10a ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Outer rolling surface 10b ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Body mounting flanges 11, 16, 26 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Cores 11a, 16a, 26a ··························· Fitting portions 11b, 16b, 26b ························· ·········· Seal members 12a, 17a ··················· Side lips 12b, 12c, 17b, 17c, 27a, 27b Lips 13, 19, 28 ...・ ・ ・ ・ ・ ・ ・ ・ ・ Coating layers 13a, 13c ・ ・ ・ ・ ・ ・ ・ ・ Metal layer 13b ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Ceramic layer 14 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Seal plates 15, 21 ・ ・ ・ ・ ・ ・... Slinger 15a, 21a ... Cylindrical part 15b, 21b ... ... Standing plate 18 ... Labyrinth seal 22a ...・ ・ ・ ・ ・ ・ ・ ・ Outer diameter surface 51 of inner ring ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Outer member 51a ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Outer rolling surface 51b ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・Car body mounting flange 52 ... Hub wheels 52a, 55a ...・ ・ ・ ・ ・ Inner rolling surface 52b ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Small diameter stepped portion 52c ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・... serration 53 ... wheel mounting flange 54 ... Hub bolt 55 ... Inner ring 56 ... Ball 57 ... Cage 58 ...・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inner members 59, 60 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Sea 61 ... cored bar 62 ... Sealing member 62a ... side lip 62b ... Grease lip 62c ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Intermediate lip 63 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ Seal plate 64 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Slinger 64a ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ Cylindrical part 64b ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Standing plate 65 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・... Labyrinth seal 66 ... Friction reducing coating

Claims (8)

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 be freely rollable via 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,
The seal includes a metal core fitted into an end portion of the outer member, and a seal member integrally bonded to the metal core by vulcanization adhesion, and having a plurality of seal lips. A wheel bearing device, wherein a coating layer including a ceramic layer is formed on a contact surface.   The wheel bearing device according to claim 1, wherein the coating layer has a laminated structure including a metal layer and a ceramic layer.   The wheel bearing device according to claim 1, wherein the coating layer is a sprayed layer, and sealing is performed after the spraying is completed.   The seal is composed of an integrated seal having a plurality of seal lips that are in sliding contact with the outer peripheral surface of the inner member via a shimoshiro, and the coating layer is formed on the outer peripheral surface of the inner member. The wheel bearing apparatus in any one of 1 thru | or 3.   From the inner rolling surface, the inner member integrally has a wheel mounting flange for mounting a wheel at one end, and is opposed to one of the outer rolling surfaces of the double row on the outer periphery. A hub ring formed with a small-diameter step portion extending in the axial direction, and a small-diameter step portion of the hub ring that is press-fitted and fixed to the outer periphery of the hub wheel through a predetermined shimoshiro, and that is inwardly facing the other of the outer rolling surfaces of the double-row. The inner side base of the wheel mounting flange is formed in a curved surface having an arc shape in cross section, and the seal has a side lip that is in sliding contact with the base through a shimishiro. The wheel bearing device according to claim 1, wherein the coating layer is formed on a surface of the base portion.   An annular seal plate having a seal member composed of a side lip and a radial lip, a cylindrical portion disposed opposite to the seal plate, externally fitted to the inner member, and in sliding contact with the radial lip; and It is constituted by a pack seal provided with a slinger consisting of a standing plate portion that extends radially outward from the cylindrical portion and to which the side lip is slidably contacted, and the surface of the slinger that is slidably contacted by the respective seal lips The wheel bearing device according to any one of claims 1 to 3, wherein a coating layer is formed.   The wheel bearing device according to claim 6, wherein the coating layer is formed on the entire surface of the slinger.   The wheel bearing device according to any one of claims 1 to 7, wherein the coating layer is formed by an aerosol position method.

Images