JP2008202729A - Sealing device for rolling bearing and rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive sealing device for a rolling bearing in simple constitution capable of preventing intrusion of mud water and improving friction resistance and abrasion resistance; and the rolling bearing using it. <P>SOLUTION: This sealing device 9 for the rolling bearing is furnished with an annular sealing plate 12 made of a sealing member 14 fixed on one of an outward member on an inner periphery of which an outside rolling surface is formed and an inward member on an outer periphery of which an inside rolling surface opposed to the outside rolling surface is formed and integrally having seal lips and a core metal 13 to reinforce this sealing member 14; and a slinger 11 provided on the other of the outward member or the inward member and to make contact with the seal lips. The slinger 11 and the sealing plate 12 are formed roughly in an L shape in their cross sections and arranged opposed to each other, and the slinger 11 has a ceramic film 11c formed by an AD method on a surface to which the seal lips 14a, 14b, 14c sliding contact. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rolling bearing seal device used for automobile wheels and the like, and more particularly to a rolling bearing seal device in which muddy water is prevented from entering under actual use conditions and low friction torque and low wear are improved. The present invention relates to a rolling bearing in which the sealing device is incorporated.

  BACKGROUND ART A wheel bearing device that supports a wheel of an automobile or the like supports a hub wheel for mounting a wheel rotatably via a double row rolling bearing, and includes a driving wheel and a driven wheel. For structural reasons, an inner ring rotation method is generally used for driving wheels, and an inner ring rotation method and an outer ring rotation method are generally used for driven wheels. Further, the wheel bearing device has a structure called a first generation in which a wheel bearing composed of a double row angular ball bearing or the like is fitted between a knuckle and a hub wheel constituting a suspension device. Second generation structure in which body mounting flange or wheel mounting flange is formed directly on the outer periphery of the member, third generation structure in which one inner rolling surface is directly formed on the outer periphery of the hub wheel, or hub wheel, etc. It is roughly classified into a fourth generation structure in which the inner rolling surface is directly formed on the outer periphery of the outer joint member of the speed universal joint.

  A seal device is attached to these bearing portions in order to prevent leakage of grease sealed inside the bearing and to prevent intrusion of rainwater, dust and the like from the outside. In recent years, the maintenance of automobiles has become more maintenance-free, and even longer bearing life has been demanded for wheel bearing devices. However, the damage due to the sealing failure is a major factor. Therefore, the bearing life can be improved by improving the sealing performance and durability of the sealing device.

A seal lip (especially a side lip) provided on a seal member fixed to the outer ring side (or inner ring side) in order to improve the sealing performance and durability of the seal used for the rolling bearing configured to seal the encapsulated lubricant. Lip) is applied to the surface of the slinger metal surface that is in sliding contact with the inner ring side (or outer ring side), such as hard chrome plating or electroless nickel plating, hard metal plating, quenching treatment, silicon nitride, etc. A hardening process such as applying a ceramic coating and various coatings by a PVD method or a CVD method is known (see Patent Document 1).
Further, in order to reduce the rotational torque of the bearing due to the contact resistance of the seal, the radial lip was eliminated, and the first and second side lips were formed in duplicate, and were brought into sliding contact with the surface of the slinger metal surface. An example is known in which high sealing performance is ensured and the contact resistance of the seal is reduced (see Patent Document 2).

However, in a seal for a rolling bearing as shown in Patent Document 1, slinger generated by polishing action due to mud particles or the like in a muddy water environment causes wear problems at the sliding contact portion with the side lip of the seal, for example, hard chrome plating or hard Even if measures were taken by forming a hardened surface layer such as metal plating, there was a problem that the torque increased due to the sliding contact of the radial lip portion.
Also, in Patent Document 2, the first side lip and the second side lip are configured to be in sliding contact with the surface of the slinger metal surface. Further, in order to reduce the fuel consumption of the vehicle, it is necessary to further reduce the frictional force due to the contact resistance of the seal.
JP 2003-262231 A JP 2005-291305 A

  The present invention has been made in view of such conventional problems, and can reduce the amount of wear on the metal surface that is in sliding contact with the seal lip, thereby preventing intrusion of muddy water and improving friction resistance and wear resistance. It is an object of the present invention to provide an inexpensive rolling bearing seal device with a simple configuration and a rolling bearing using the same.

  The rolling bearing sealing device of the present invention is fixed to one of an outer member having an outer rolling surface formed on the inner periphery or an inner member having an inner rolling surface opposed to the outer rolling surface on the outer periphery. An annular seal plate comprising a seal member integrally having a seal lip and a core metal that reinforces the seal member, and a slinger provided on the other of the outer member and the inner member and contacting the seal lip , Wherein the slinger and the seal plate have a substantially L-shaped cross section and are arranged to face each other, and the slinger is slid on the seal lip. A ceramic film formed by an aerosol deposition method (hereinafter referred to as an AD method) is provided on a contact surface.

The ceramic coating is a coating using ceramic fine particles having an average particle size of 0.01 μm to 2 μm as an aerosol raw material.
The ceramic fine particles are silicon nitride or silicon carbide fine particles.

  The rolling bearing of the present invention includes an outer member having an outer rolling surface formed on the inner periphery, an inner member having an inner rolling surface opposed to the outer rolling surface on the outer periphery, and both of these rolling members. A rolling bearing comprising a rolling element rotatably accommodated between surfaces, and a seal device mounted in an annular space formed between the outer member and the inner member, the rolling bearing seal device It is characterized by using.

A seal device for a rolling bearing according to the present invention is provided with a seal for a rolling bearing provided with an annular seal plate made up of a seal member integrally having a seal lip, a core metal that reinforces the seal member, and a slinger that contacts the seal lip. Since the slinger has a ceramic film with a low coefficient of friction formed by the AD method on the surface where the seal lip contacts, mud particles or the like enter the muddy water environment at the sliding contact portion between the slinger and the seal lip. However, it is possible to prevent an increase in rotational torque due to friction, damage to the sliding contact surface due to wear, and the like, thereby improving the sealing performance.
Also, since the ceramic coating is formed from silicon nitride fine particles, silicon oxide is generated by a tribochemical reaction on the sliding contact surface, preventing solid contact between the base materials, reducing wear and reacting with invading water. By acting as a lubricant, it is possible to impart a friction reducing effect.
Further, by forming the ceramic film by the AD method, the film formation rate is much faster than that of the ceramic film formed by the PVD method or the CVD method, and a high vacuum is not required, so that it can be manufactured at a very low cost.

  Since the rolling bearing of the present invention uses the sealing device, the sliding contact surface of the sealing device can prevent an increase in rotational torque due to friction, damage to the sliding contact surface due to wear, and the like, and can extend the life.

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 rolling bearing of the present invention. This rolling bearing is applied to a wheel bearing for rotatably supporting a driving wheel of an automobile with respect to a suspension device. FIG. 2 is an enlarged view of an essential part showing an example of the sealing device of the present invention installed on the inner side of FIG. FIG. 3 is a perspective view showing the slinger of FIG. In the following description, the side closer to the outside of the vehicle in the state assembled to the vehicle is referred to as the outer side (left side in the drawing), and the side closer to the center is referred to as the inner side (right side in the drawing).

  The wheel bearing is for a follower wheel, and includes an inner member 1 and an outer member 10, and double row rolling elements (balls) 7 and 7 accommodated between the members 1 and 10 in a freely rolling manner. The configuration is called the third generation. The inner member 1 includes a hub ring 2 and an inner ring 3 press-fitted into the hub ring 2 with a predetermined tightening allowance.

  The hub wheel 2 integrally has a wheel mounting flange 4 for mounting a wheel at one end portion, one (outer side) inner rolling surface 2a on the outer periphery, and a small diameter step extending in the axial direction from the inner rolling surface 2a. Part 2b is formed. Further, hub bolts 4 a are implanted in the circumferentially equidistant positions of the wheel mounting flanges 4. The inner ring 3 is formed with the other (inner side) inner rolling surface 3a on the outer periphery, and is press-fitted into the small-diameter step portion 2b of the hub ring 2 through a predetermined allowance. The end portion of the small-diameter step portion 2b is fixed in the axial direction with respect to the hub wheel 2 in a state in which a preload is applied by a caulking portion 5 formed by plastically deforming the outer end in the radial direction.

  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 formed. Between these rolling surfaces 10a, 2a and 10a, 3a, double row rolling elements 7, 7 are accommodated via a cage 6 so as to roll freely. This outer member 10 is formed of medium carbon steel containing 0.40 to 0.80% by weight of carbon such as S53C, and at least the double row outer rolling surfaces 10a and 10a are hardened in the range of 58 to 64 HRC by induction hardening. Has been processed.

  Sealing devices 8 and 9 are attached to both ends of the outer member 10 to seal the opening of the annular space formed between the outer member 10 and the inner member 1. At least the sealing device 9 is the rolling bearing sealing device of the present invention. The sealing devices 8 and 9 prevent the lubricating grease enclosed in the bearing from leaking to the outside and preventing rainwater, dust, and the like from entering the bearing from the outside.

  The hub wheel 2 is formed of medium carbon steel containing 0.40 to 0.80% by weight of carbon such as S53C and is induction-hardened from the base of the wheel mounting flange 4 serving as the seal land portion of the outer seal device 8 to the small diameter step portion 2b. The surface is hardened in the range of ~ 64 HRC. The caulking portion 5 is left as it is after forging. On the other hand, the inner ring 3 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.

  Here, the sealing device 9 of the present invention on the inner side is composed of a slinger 11 and an annular sealing plate 12 arranged to face each other as shown in an enlarged view in FIG. Slinger 11 is made of austenitic stainless steel plate (JIS standard SUS304 type, etc.) or rust-proof cold rolled steel plate (JIS standard SPCC type, etc.) by pressing to form a substantially L-shaped cross section. The cylindrical portion 11a is press-fitted into the inner ring 3, and the upright plate portion 11b extends radially from the cylindrical portion 11a. As shown in FIG. 2 and FIG. 3, the slinger 11 includes a vertical plate portion 11b that is a sliding contact surface of the outer seal lip 14a, and a cylindrical portion 11a that is a sliding contact surface of the middle sealing lip 14b and the inner sealing lip 14c. A ceramic film 11c is formed by the AD method. Since the rust prevention treatment and the ceramic coating 11c can prevent rusting and wear on the sliding surface of the slinger 11, the durability of the sealing device 9 can be improved and the cost can be reduced. The ceramic coating 11c may be formed in the vicinity where at least the tip of each seal lip is in sliding contact.

  On the other hand, the seal plate 12 has a substantially L-shaped cross section and is attached to the outer member 10. The seal plate 12 includes a metal core 13 and a seal member 14 vulcanized and bonded to the metal core 13. The core 13 is formed by press working 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 cylindrical portion 13a is fitted into the end portion of the cylinder 10 and the upright plate portion 13b extends radially inward from the cylindrical portion 13a.

  The seal member 14 is made of an elastic member such as nitrile rubber, and includes an outer seal lip 14a that is in sliding contact with the standing plate portion 11b of the slinger 11, an inner seal lip 14b that is in sliding contact with the cylindrical portion 11a, and an inner seal lip 14c. . The outer seal lip 14a is formed so as to be inclined from the standing plate portion 13b of the core bar 13 toward the outer diameter side, and the tip thereof is in sliding contact with the standing plate portion 11b of the slinger 11 with a predetermined margin. The middle seal lip 14b and the inner seal lip 14c are formed so as to incline from the upright plate portion 13b of the core bar 13 toward the inner diameter side, and their tips are in sliding contact with the cylindrical portion 11a of the slinger 11 with a predetermined tightening margin.

  In addition, although the double row angular contact ball bearing which used the ball for the rolling element 7 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 7 may be sufficient. In addition, the rolling bearing (device) according to the present invention can be applied to, for example, a first generation, a second generation, or a fourth generation structure in addition to the third generation structure illustrated as long as it is an inner ring rotating system. . In the case of the first generation and the second generation, the rolling bearing sealing device according to the present invention can be applied not only to the inner side but also to the outer side.

FIG. 4 is an enlarged view of an essential part showing another embodiment of the sealing device of the present invention shown in FIG. FIG. 5 is a perspective view showing the slinger of FIG. In this embodiment, the installation form of the seal lip and the ceramic film of the seal device described with reference to FIGS. 2 and 3 is changed as follows.
As shown in FIGS. 4 and 5, in the slinger 11, a ceramic film 11d is formed by an AD method on a standing plate portion 11b which is a surface where the side lips 14e and 14f are in sliding contact. The rust prevention treatment and the ceramic coating can prevent rusting and abrasion on the sliding contact surface of the slinger 11, so that the durability of the seal device 9 can be improved and the cost can be reduced. The ceramic coating 11d may be formed in the vicinity where at least the tip of each seal lip is in sliding contact.

  On the other hand, the seal member 14 is made of an elastic member such as nitrile rubber, and has first and second side lips 14e and 14f that are in sliding contact with the standing plate portion 11b of the slinger 11. These first and second side lips 14e and 14f are formed to be inclined from the standing plate portion 13b of the core metal 13 toward the outer diameter side, and their tips have a predetermined allowance on the standing plate portion 11b of the slinger 11. It is in sliding contact.

  Further, the seal member 14 wraps around and adheres to the outer surface of the cylindrical portion 13a of the core metal 13 to improve airtightness, and wraps around and adheres to the inner edge of the standing plate portion 13b of the core metal 13 to form a cylinder. A shaped inner end portion 14d is formed. A labyrinth seal 16 is formed by forming an annular clearance between the inner end portion 14d and the cylindrical portion 11a of the slinger 11, thereby preventing the grease enclosed in the bearing from leaking to the outside. . Further, the labyrinth seal 15 is configured by causing the outer edge of the standing plate portion 11b of the slinger 11 and the cored bar 13 to face each other through a slight gap, and rainwater, dust, and the like are directly supplied from the outside to the first and second side lips 14e, It is prevented from falling to 14f.

  Thus, in this embodiment, it has the 1st and 2nd side lips 14e and 14f which slidably contact with the standing board part 11b of the slinger 11 with a predetermined interference, and the outer edge and cored bar of the standing board part 11b in the slinger 11 In addition to the labyrinth seal 15 formed between the labyrinth seal 13 and the labyrinth seal 16 between the inner end portion 14d of the seal portion 14 and the cylindrical portion 11a of the slinger 11, high sealing performance is ensured. It is possible to provide a rolling bearing sealing device that reduces the torque of the bearing.

  Further, in these first and second side lips 14e, 14f, the tightening allowance of the first side lip 14e is set larger than the tightening allowance of the second side lip 14f. As a result, the wear of the second side lip 14f is suppressed, and even if the first side lip 14e is worn and the tightening margin is reduced, the two side lips with the second side lip 14f are highly sealed over a long period of time. Sex can be maintained.

  In the present invention, the method of forming a ceramic coating by the AD method is that an aerosol in which ceramic fine particles as a raw material are dispersed in a gas is sprayed from an aerosol spray nozzle toward a slinger as a base material, and the aerosol is rapidly applied to the surface of the base material. The film is formed by a method of forming a film made of a constituent material of fine particles on a substrate.

Examples of the ceramic fine particles used as an aerosol raw material for forming a ceramic coating by the AD method in the present invention include oxides such as alumina, zirconia and titania, and fine particles such as silicon carbide and silicon nitride. In addition to the ceramic fine particles, fine particles of a brittle material having a strong cleavage, such as silicon and germanium, can be used.
Among these, particularly preferable ceramics are silicon nitride and silicon carbide. Regarding the frictional wear reduction mechanism in water by silicon nitride and silicon carbide, silicon oxide is generated by tribochemical reaction on the friction surface, and the silicon oxide is softer than the base material, and the solid contact between the base materials on the sliding surface , And the plastic deformation reduces the stress concentration and reduces the wear leading to fracture. Furthermore, by reacting with water, it becomes a softer hydroxide or hydrate, which acts as a lubricant and imparts a friction reducing effect.
Due to the effect of reducing the friction coefficient between the seal lip surface and the slinger surface on which the ceramic film is formed, the contact resistance on the sliding surface is reduced, and the rotational torque of the bearing is reduced.

The average particle size of the ceramic fine particles used in the present invention is preferably 0.01 μm to 2 μm. If it is less than 0.01 μm, it tends to agglomerate and it is difficult to form an aerosol. If it exceeds 2 μm, the proportion of fine particles that do not contribute to film formation increases, and the film formation efficiency decreases and the cost increases. In the present invention, the average particle diameter is a value measured by Nikkiso Co., Ltd .: Laser type particle size analyzer Microtrac MT3000.
Further, in order to satisfactorily form a film, it is preferable to previously form cracks in the fine particles using a pulverizer such as a ball mill or a jet mill so that the fine particles are easily pulverized upon collision with the substrate.

A method of forming a film on the slinger in the present invention will be described based on a film forming apparatus 17 shown in FIG.
Ceramic fine particles are put into the aerosol generator 24, the vacuum pump 26 is activated, and the aerosol generator 24 is depressurized via the vacuum chamber 19. A carrier gas is supplied from the gas supply facility 23 to the aerosol generator 24 to form an aerosol composed of ceramic fine particles and a carrier gas. The aerosol is supplied to the aerosol injection nozzle 18 of the vacuum chamber 19. Examples of usable carrier gas include inert gases such as argon, nitrogen, and helium. In addition, a filter 25 is provided to prevent fine particles and foreign matter from entering the vacuum pump.

In the vacuum chamber 19, the aerosol is sprayed from the aerosol spray nozzle 18 toward the slinger 22 as a base material, and a ceramic film is formed on the slinger 22.
The slinger 22 is attached to an object rotation motor 21 connected to the positioning XY table 20, rotated by the object rotation motor 21 (B in the figure), and moved in the horizontal direction by the positioning XY table 20. (A in the figure). While rotating and moving the slinger, aerosol is sprayed onto the standing plate portion of the slinger to form a film. The film formation is performed until a predetermined film thickness is obtained.

Example 1
Slinger (made of SUS430, cylindrical part: inner diameter 61.5 mm x outer diameter 63.1 mm x length 5.5 mm, standing plate part: 5.8 mm x outer diameter 75 mm x thickness 0.8 mm) with a standing plate (11b in Fig. 3) Got ready. This slinger is attached to an object rotating motor 21 connected to the XY table 20 of the film forming apparatus by the AD method shown in FIG. 6, and silicon nitride (SN-E10, manufactured by Ube Industries, average particle diameter 0.55 μm) as a ceramic material. ) Into the aerosol generator 24, the vacuum pump 26 is started, the vacuum chamber 19 is depressurized to 100 Pa or less, nitrogen gas is supplied as a carrier gas from the gas supply facility 23 to the aerosol generator 24, and the aerosol is Generated. This aerosol was sprayed from an aerosol spray nozzle 18 (opening size: 10 mm × 2.0 mm) onto a slinger standing plate 11b as a base material to form a silicon nitride film having a thickness of 5 μm.
The obtained slinger was attached to a sealing device (0.3 g of grease applied between seal lips) and evaluated by the method shown below. The results are shown in Table 1.

<Torque test>
For the created seal device, the torque in a stable state after 30 minutes was measured using a seal rotation tester under the following conditions. The results are shown in Table 1.
Rotation speed: 1000 rpm
Shaft eccentricity: 0.05 mm T.D. I. R (Total Indication Reading)
Mounting eccentricity: 0.05 mm I. R
Lip fastening allowance: Median seal design shape

Example 2
The sealing device obtained by treating in the same manner as in Example 1 except that silicon carbide (made by Showa Denko KK, DUA-1, average particle size 0.45 μm) was used as the ceramic material in Example 1 was evaluated by the above method. did. The results are also shown in Table 1.

Comparative Example 1
The sealing device obtained without forming the ceramic coating was evaluated by the above method. The results are also shown in Table 1.

  The rolling bearing sealing device of the present invention uses a slinger having a ceramic coating with a low friction coefficient formed by the AD method on the sliding contact surface of the seal lip, so that a muddy water environment is formed at the sliding contact portion between the slinger and the seal lip. Even if mud or the like enters, it is possible to prevent an increase in rotational torque due to friction, damage to the sliding contact surface due to wear, and the like, and improve the sealing performance. For this reason, the rolling bearing using this rolling bearing seal device has excellent bearing life even when used in an environment where muddy water enters, and can be suitably used as a wheel bearing used for an automobile wheel or the like.

It is a longitudinal cross-sectional view which shows the rolling bearing of this invention. It is a principal part expanded sectional view which shows an example of the inner side sealing apparatus of FIG. It is a perspective view which shows the slinger of FIG. It is a principal part expanded sectional view which shows the other example of the inner side sealing apparatus of FIG. It is a perspective view which shows the slinger of FIG. It is a figure which shows a film formation apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner member 2 Hub wheel 2a, 3a Inner rolling surface 2b Small diameter step part 3 Inner ring 4 Car body mounting flange 4a Hub bolt 5 Clamping part 6 Cage 7 Rolling body 8 Outer side sealing device 9 Inner side sealing device 10 Outer member 10a Outer rolling surface 10b Car body mounting flange 11 Slinger 11a, 13a Cylindrical portion 11b, 13b Standing plate portion 11c Ceramic coating 11d Ceramic coating 12 Seal plate 13 Core metal 14 Seal member 14a Outer seal lip 14b Middle seal lip 14c Inner seal lip 14d Inner end portion 14e First side lip 14f Second side lip 15 Labyrinth seal 16 Labyrinth seal 17 Film forming device 18 Aerosol injection nozzle 19 Vacuum chamber 20 XY table for positioning 21 Motor for object rotation 22 Slin Moth (base material)
23 Gas supply equipment 24 Aerosol generator 25 Filter 26 Vacuum pump

Claims (4)

A sealing member that is fixed to one of an outer member having an outer rolling surface formed on the inner periphery or an inner member having an inner rolling surface opposite to the outer rolling surface formed on the outer periphery, and integrally having a seal lip. And a ring seal plate comprising a metal core that reinforces the seal member, and a slinger provided on the other of the outer member or the inner member and a slinger that contacts the seal lip. There,
In the sealing device, the slinger and the seal plate are formed in a substantially L-shaped cross section so as to be opposed to each other, and the slinger is formed by an aerosol deposition method on a surface in contact with the seal lip. A rolling bearing sealing device characterized by comprising:   2. The bearing seal device according to claim 1, wherein the ceramic coating is a coating using ceramic fine particles having an average particle diameter of 0.01 to 2 [mu] m as an aerosol raw material.   The rolling bearing seal device according to claim 2, wherein the ceramic fine particles are fine particles of silicon nitride or silicon carbide. An outer member having an outer rolling surface formed on the inner periphery, an inner member having an inner rolling surface facing the outer rolling surface on the outer periphery, and rotatably accommodated between both the rolling surfaces. A rolling bearing comprising: a rolling element formed; and a sealing device mounted in an annular space formed between the outer member and the inner member;
The rolling bearing according to claim 1, 2 or 3, wherein the sealing device is a rolling bearing sealing device.

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