JP2003184897A - Sealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a sealing device 12 having an improved sealing performance. <P>SOLUTION: A sealing member 16 comprises an outside seal-lip 23, an intermediate seal-lip 24, and an inside seal lip 25, which come into slide-contact with a to-be-slid-contacted surface in the surface of a slinger 18. The surface roughness of the surface coming in slide-contact with the lips 23, 24, 25 is specified to be 0.3 μm or less in the center-line average roughness (Ra), and 1.2 μm or less in the maximum height (Ry). Thus, a minute gap is hard to generate between the lips 23, 24, and 25 and the slid-contact surface, consequently, an improved sealability is ensured. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing device used in an environment where a large amount of foreign matter such as water, muddy water, oil, and dust exists in the surroundings, for example, a hub unit for automobiles and a bearing unit for water pumps. The present invention relates to improvement of a seal device to be assembled.

[0002]

2. Description of the Related Art Rolling bearing devices including rolling bearings such as ball bearings, roller bearings and tapered roller bearings are incorporated in the rotation supporting portions of various mechanical devices. In such a rolling bearing device, the sealing device provided at the opening end of the rolling bearing device prevents the grease enclosed therein from leaking to the outside, and prevents various foreign substances such as water and dust existing outside from leaking to the inside. Prevent entry. An example of a rolling bearing device assembled with such a seal device will be described with reference to FIG. 1 showing a first example of an embodiment of the present invention.

FIG. 1 shows, as an example of a rolling bearing device incorporating a sealing device to which the present invention is applied, a vehicle hub unit for rotatably supporting a vehicle wheel with respect to a suspension device. 1 shows an example of an automobile hub unit for drive wheels (front wheels of FF vehicle, rear wheels of FR vehicle and RR vehicle, all wheels of 4WD vehicle). Outer ring 1 which is a stationary member
Is supported and fixed to the suspension device by the mounting portion 2 formed on the outer peripheral surface thereof, and does not rotate during use. On the inner diameter side of such an outer ring 1, an inner ring equivalent member 3 which is a rotating member is provided concentrically with the outer ring 1 so that the inner ring equivalent member 3 rotates during use. The member 3 corresponding to the inner ring is the hub 4
And inner ring 5. A spline hole 6 is formed in the center of the hub 4, and a mounting flange 7 is formed on the outer peripheral surface of the outer end (the end that is the outer side in the width direction when assembled to a vehicle; the left end in FIGS. 1 and 2). Is forming. At the time of assembly to a vehicle, a spline shaft attached to a constant velocity joint (not shown) is inserted into the spline hole 6, and a wheel is fixed to the mounting flange 7.

Further, double rows of outer ring raceways 8 and 8 are formed on the inner peripheral surface of the outer ring 1, and inner ring raceways 9 and 9 are formed on the outer peripheral surface of the intermediate portion of the hub 4 and the outer peripheral surface of the inner ring 5, respectively. There is. A plurality of rolling elements 10 and 10 are provided between the outer ring raceways 8 and 8 and the inner ring raceways 9 and 9, respectively, so that the inner ring equivalent member 3 can freely rotate inside the outer ring 1. There is. The rolling elements 10 and 10 are rotatably held by cages 11 and 11, respectively. or,
In the illustrated example, balls are used as the rolling elements 10 and 10, but in the case of a hub unit for a vehicle that is heavy in weight, tapered rollers may be used as the rolling elements. Further, a sealing device is provided between an inner end surface of the outer ring 1 (referred to as an end on the widthwise center side when assembled in a vehicle, which is the right end in FIGS. 1 and 2) and an inner end outer peripheral surface of the inner ring 5. A seal ring 13 is provided between the inner peripheral surface of the outer end portion of the outer ring 1 and the outer peripheral surface of the intermediate portion of the hub 4. Then, the sealing device 12 and the seal ring 13 close both end openings of the space 14 in which the rolling elements 10, 10 are installed between the inner peripheral surface of the outer ring 1 and the outer peripheral surface of the inner ring equivalent member 3. I'm out.

These seal device 12 and seal ring 13
As shown in FIG. 2, the seal device 12 for closing the inner end opening of the space 14 has a seal ring 1 including a core metal 15 and a seal member 16 each formed in an annular shape.
7 and a slinger 18 which is also formed in an annular shape. The core metal 1 constituting the seal ring 17 among them
5 is integrally formed by subjecting a metal plate such as a low carbon steel plate to punching such as press working and plastic working. Such a cored bar 15 includes an outer diameter side cylindrical portion 19 which can be fitted and fixed to the inner peripheral surface of the inner end portion of the outer ring 1, and an axial outer end edge (the left end edge in FIG. 2) of the outer diameter side cylindrical portion 19. ) And an inner circular ring portion 20 that is bent inward in the diametrical direction, and has a substantially L-shaped cross section and has a circular shape as a whole.

The slinger 18 is integrally formed by subjecting a metal plate having excellent corrosion resistance such as a stainless steel plate to punching such as press working and plastic working. Such a slinger 18 has an inner diameter side cylindrical portion 21 which can be externally fitted and fixed to the outer peripheral surface of the inner end portion of the inner ring 5, and a diametrically outer portion from the inner end edge (the right end edge in FIG. 2) of the inner diameter side cylindrical portion 21. The outer ring portion 22 is bent in one direction, and has an L-shaped cross section, and has an annular shape as a whole.

The seal member 16 is made of an elastic material such as an elastomer such as rubber and has three seal lips 23, 24 and 25 on the outer side, the middle side and the inner side. The ends are fixed together. Then, with respect to the inward and outward directions of the space 14, the tip edge of the outer seal lip 23 located on the outermost side is slidably contacted with the inner side surface of the outer ring portion 22 constituting the slinger 18, and the remaining two seal lips are used. Sliding the tip edges of the intermediate seal lip 24 and the inner seal lip 25 with the outer peripheral surface of the inner diameter side cylindrical portion 21 forming the slinger 18 prevents grease from leaking from the space 14. Foreign matter such as water, muddy water, oil, and dust is prevented from entering the space 14 from the outside.

On the other hand, the seal ring 13 for closing the outer end opening of the space 14 is composed of a core metal 26 and a seal member 27 each formed in an annular shape. The core metal 26
Is integrally formed by subjecting a metal plate such as a low carbon steel plate to punching such as press working and plastic working.
The seal member 27 is made of an elastic material such as elastomer such as rubber. The seal member 27 is fixed to the core metal 26 by molding the core metal 26 in the cavity of the molding die. In such a seal member 27, the outer edges of the space 14 are opened by directly sliding the tip edges of the seal lips 28a, 28b, 28c provided on the seal member 27 onto the surface of the hub 4. Is sealed.

[0009]

In the case of the seal units 12 and 12a (see FIG. 4 described later) incorporated in a hub unit for a vehicle configured as described above, a bearing unit for a water pump described below, etc. Higher sealing performance is required in accordance with higher performance of. However, in the case of the conventional sealing device, there is a possibility that the required sealing performance cannot be sufficiently ensured. That is, in the case of the conventional sealing device, a minute gap exists between each seal lip that constitutes the sealing device and the peripheral surface of the slinger with which the seal lip is in sliding contact, due to minute unevenness existing on the peripheral surface of the slinger. Can occur based on More specifically, conventionally, the surface roughness of the peripheral surface of the slinger is 0.8 μm or less in terms of center line average roughness (Ra), and is substantially 0.4 to 0.6 μm.

For this reason, the seal device 12 shown in FIGS. 1 and 2 will be described as an example. Due to such unevenness, minute gaps may occur between the surfaces of these respective parts 21 and 22 and the respective seal lips 23, 24 and 25. If a minute gap is created between the seal lip and the slinger surface, foreign matter such as water or oil will enter the rolling bearing device (such as a hub unit for automobiles or a bearing unit for a water pump) from the outside. , There is a possibility that it will gradually invade, although it is in small amounts.

The entry of such foreign matter such as water or oil causes deterioration such as emulsification of the grease that lubricates the rolling contact portion, and damage such as early peeling occurs at the rolling contact portion due to poor lubrication. there is a possibility. Moreover, when such damage is significant, the rolling bearing device may reach the end of its life before the automobile is discarded due to the end of its useful life. The present invention has been made in view of the above circumstances to realize a sealing device having excellent sealing performance.

[0012]

The sealing device of the present invention comprises:
The rolling bearing device is held by the stationary side member in order to close the end opening of the space existing between the peripheral surface of the rotating side member and the peripheral surface of the stationary side member where a plurality of rolling elements are installed. A seal ring and a slinger fixed to the rotary member are provided. The tip end edge of a seal lip made of an elastic material that constitutes the seal ring is in sliding contact with the surface (peripheral surface or side surface) of the slinger over the entire circumference. In particular, in the sealing device of the present invention, the surface roughness of at least the portion of the surface of the slinger that is in sliding contact with the seal lip is 0.3 μm or less in terms of center line average roughness (Ra), and The maximum height (Ry) is 1.2 μm or less. If necessary, the slinger may be a metal plate plated with corrosion resistance, and a solid lubricant may be contained in the corrosion resistance plating.

[0013]

In the case of the sealing device of the present invention configured as described above, between the seal lip forming the sealing device and the slidable contact surface of the slinger with which the sealing lip slides,
A minute gap is less likely to occur, and sufficient sealing performance can be ensured. Therefore, excellent sealing performance can be exhibited even when used in a severe environment exposed to foreign matters such as water, muddy water, oil, and dust. As a result, it is possible to contribute to the performance improvement of various rolling bearing devices such as a hub unit for an automobile and a bearing unit for a water pump.

The center line average roughness (Ra) is 0.3 μm.
If it exceeds, the unevenness of the slidable contact surface of the slinger becomes too conspicuous, and a minute gap is likely to occur between the slidable contact surface and the seal lip. Then, deterioration of grease or the like due to intrusion of foreign matter such as water, muddy water, or oil from the outside is likely to occur, and damage such as peeling is likely to occur at the rolling contact portion. On the other hand, when the maximum height (Ry) exceeds 1.2 μm, a minute (however, larger than other portions) gap is likely to occur at this maximum height portion, and therefore the same as the case described above. Foreign matter is likely to enter from the outside, and the rolling contact portion is likely to be damaged due to alteration of grease or the like.

[0015]

1 and 2 show, as a first example of an embodiment of the present invention, a sealing device incorporated in an automobile hub unit for rotatably supporting an automobile wheel with respect to a suspension device. , The case where the present invention is applied is shown. The basic structure of the hub unit for an automobile is the same as that described with reference to FIG. 1 as an example of the rolling bearing device incorporating the seal device which is the subject of the present invention. Will be omitted or simplified, and the characteristic part of the present invention will be mainly described below.

In the case of the present embodiment, a sealing device 12 is provided between the inner peripheral surface of the inner end portion of the outer ring 1 and the outer peripheral surface of the inner end portion of the inner ring 5, and the inner peripheral surface of the outer end portion of the outer ring 1 and the outer peripheral portion of the intermediate portion of the hub 4. Sealing rings 13 are provided between the respective surfaces. Then, the rolling elements 10 and 10 are provided between the inner peripheral surface of the outer ring 1 which is a stationary side member and the outer peripheral surface of the inner ring equivalent member 3 which is a rotating side member formed by the inner ring 5 and the hub 4. Space 1 installed
Both ends of 4 are closed. Of the sealing device 12 and the sealing ring 13, the sealing device 12 that closes the inner end opening of the space 14 includes a core metal 15 and a sealing member 16 each formed in an annular shape, as shown in FIG. And a slinger 18 which is also formed in an annular shape.

The slinger 18 is made of a stainless steel plate, a stainless steel plate, a cold rolled steel plate plated with corrosion resistance, or a metal plate having excellent corrosion resistance against corrosion by water, oil, muddy water, or the like. Constitute. As the corrosion-resistant plating applied to such a metal plate, nickel plating, zinc plating, zinc-iron alloy plating, zinc-nickel alloy plating, tin plating and the like are preferable. However, chrome plating, which is the most common type of corrosion-resistant plating, uses chromic acid as a raw material and may leave traces of harmful hexavalent chromium.
Not preferable from the viewpoint of pollution prevention. Each of the above corrosion resistant platings may be applied individually, but in each of these corrosion resistant platings, for example, polytetrafluoroethylene (PTF) may be used.
Fluorine resin including E) or molybdenum disulfide,
A composite plating containing a solid lubricant such as graphite may be used.

When such a solid lubricant is contained in the film, the friction coefficient is reduced, and thus the rotational torque due to the friction of the seal lips 23, 24, 25 constituting the seal member 16 can be reduced. The content of such solid lubricant is 5 to 35% by volume, more preferably 15 to 25% by volume. If the content of the solid lubricant is less than 5% by volume, the effect of reducing the friction coefficient due to the addition cannot be sufficiently achieved, which is disadvantageous in terms of cost effectiveness. On the other hand, when the content of the solid lubricant exceeds 35% by volume, the portions that are in sliding contact with the respective seal lips 23, 24, 25 are likely to be worn, and the slinger 18, and thus the sealing device 12, of the slinger 18 are extended. It becomes difficult to ensure sufficient durability. Each of the above-mentioned corrosion-resistant plating may be either electrolytic plating or electroless plating.

Further, the average amount of the above corrosion-resistant plating (the amount of plating deposited on one surface of a substrate such as a stainless steel plate, which is proportional to the thickness of the plating film) is 2 to 25 g / m.
² is preferable. It should be noted that this average amount of adhesion refers to the sum of the average amounts of adhesion of these plating layers when a plurality of plating layers are provided to ensure more sufficient corrosion resistance. In addition, when this average adhesion amount is less than 2 g / m ² ,
Since the plating film is too thin, the probability of appearance of pinholes, which are untreated parts where this plating film does not exist, increases.
As a result, rust tends to occur starting from that portion, and on the contrary, it becomes difficult to ensure sufficient corrosion resistance. on the other hand,
When the above-mentioned average adhesion amount exceeds 25 g / m ² , the corrosion resistance can be secured by increasing (increasing) the adhesion amount, but the cost of the corrosion-resistant plating treatment increases. Further, even if it is too large, the corrosion resistance cannot be further improved, which is not preferable. Incidentally, in consideration of compatibility between ensuring corrosion resistance and cost reduction, the above-mentioned average amount of adhesion is 5 to 15 g / m ²
Is more preferable.

As the stainless steel plate forming the slinger 18, for example, austenitic, ferritic, martensitic, precipitation hardening stainless steel can be used. Of these, the austenitic stainless steel is a stainless steel containing 16% or more of chromium (Cr) and other nickel (Ni), such as SUS304 and SUS316.
Etc. are preferred. The ferritic stainless steel is a stainless steel containing 13% or more of chromium and molybdenum (Mo), and SUS430 or the like is preferable. or,
The martensitic stainless steel contains 13% chromium.
% Or more, and further contains a large amount of carbon (C), and is a stainless steel whose hardness is increased by heat treatment, and for example, SUS440C is preferable. In addition, the above precipitation-hardening stainless steel contains 1% of chromium.
A stainless steel containing 7% or more and having a high hardness by performing precipitation hardening heat treatment after cold rolling (cold rolling) to generate an intermetallic compound containing fine aluminum (Al) in martensite, for example, SUS631 and the like are preferable. When priority is given to corrosion resistance, the austenitic and ferritic stainless steels are preferable, but the sealing lips 23, 24,
There is a possibility that the wear resistance of the portion that is in sliding contact with 25 cannot be sufficiently secured.

On the other hand, in the case of the above-mentioned martensitic stainless steel and precipitation hardening stainless steel, since it can be hardened by heat treatment, it is easy to secure wear resistance. However, when such a martensitic or precipitation hardening stainless steel is used, it is more preferable to carry out the above-mentioned corrosion-resistant plating in order to secure the corrosion resistance. Incidentally, in the case of applying corrosion-resistant plating to a martensitic or precipitation hardening stainless steel plate as described above, it is more preferable to use electroless nickel plating which can be hardened by heat treatment at the same time. This electroless nickel plating generally contains phosphorus (P) in addition to nickel (Ni), but other than that, alloy plating containing boron (B) and tungsten (W), P
It is also preferable to use composite plating containing a solid lubricant such as TFE (polytetrafluoroethylene) / BN (boron nitride) / SiC (silicon carbide).

In the case of this example, the slinger 1 is used.
Of the surfaces of 8, the outer, middle, and inner seal lips 23, 24, 25 forming the seal member 16 are in sliding contact, that is, the outer peripheral surface of the inner diameter side cylindrical portion 21 forming the slinger 18. Similarly, the surface roughness with the inner side surface of the outer ring portion 22 is set to 0.3 μm or less in the center line average roughness (Ra) and 1.2 μm (more preferably 0.8 μm) in the maximum height (Ry). ) Below. In order to regulate the surface roughness in this way, the target surface roughness, that is, the center line average roughness is smaller than 0.3 μm and the maximum height is smaller than 1.2 μm by press working. This plate material is formed into a desired shape (slinger 18) by applying. Further, when the target surface roughness cannot be obtained by such processing, the surface roughness is improved (the value is lowered) by performing surface processing such as lapping after the press processing,
A target surface roughness may be obtained. It should be noted that the portion that regulates the surface roughness of the slinger in this way is only the portion of the surface of the slinger 18 that is in sliding contact with the seal lips 23, 24, 25, and the other portions may be somewhat rough. good.
That is, in order to suppress an increase in manufacturing cost, the slinger 1
Of the eight, for example, the inner peripheral surface of the inner diameter side cylindrical portion 21 and the outer peripheral surface of the outer circular ring portion 22 may have a slightly rough surface without restricting the surface roughness as described above.

The sealing device 12 of the present example configured as described above.
In the case of, each of the above seal lips 23, 24, 25,
A minute gap is less likely to be formed between the seal lips 23, 24, 25 and the slidable contact surface of the slinger 18 with which the seal lips 23, 24, 25 are in sliding contact, and sufficient sealing performance can be ensured. Therefore,
Excellent sealing performance can be achieved even when used in a harsh environment exposed to foreign matter such as water, muddy water, oil, and dust. As a result, it is possible to contribute to improving the performance of the hub unit for automobiles, centering on the durability.

The center line average roughness (Ra) is 0.3 μm.
When it exceeds, the unevenness of the slidable contact surface of the slinger 18 becomes too conspicuous, and a minute gap is apt to occur between the slidable contact surface and each of the seal lips 23, 24, 25. Then, deterioration of grease or the like due to intrusion of foreign matter such as water, muddy water, or oil from the outside is likely to occur, and damage such as peeling is likely to occur at the rolling contact portion. On the other hand, the maximum height (R
If y) exceeds 1.2 μm, a minute gap is created at this maximum height part, but a large gap is likely to occur compared to other parts, so foreign matter is likely to enter from the outside as in the case described above. Therefore, the rolling contact portion is likely to be damaged due to the deterioration of grease or the like.

Next, FIGS. 3 to 4 show, as a second example of the embodiment of the present invention, a case where the present invention is applied to a seal device assembled to a bearing unit for a water pump. A rotating shaft 30 of a water pump 29 for circulating cooling water of an automobile engine is rotatably supported by a bearing unit 31. This example shows the case where the present invention is applied to the sealing device 12a (see FIG. 4) assembled to such a bearing unit 31.
Incidentally, FIG. 3 shows a drive mechanism for rotationally driving a cooling fan 32 for blowing air to a radiator for radiating cooling water and the water pump 29 by a single rotary shaft 30.

That is, the rotating shaft 30 rotatably supports the intermediate portion thereof by the bearing unit 31 supported by the housing 33 of the water pump 29.
Further, an impeller 34 is located at a portion located inside the housing 33 at an inner end portion (right end portion in FIG. 3) of the rotary shaft 30, and is located outside the housing 33 at an outer end portion (left end portion in FIG. 3). The driven pulleys 35 are fixed to the respective portions. An endless belt 36 is stretched between the driven pulley 35 and a drive pulley (not shown) fixed to the end of a crankshaft so that the rotary shaft 30 can be driven to rotate during engine operation.

Further, the driven pulley 35 is connected to the rotary shaft 30.
The cooling fan 32 is supported on the outer half portion (the left half portion in FIG. 3) of the inner hub 37 for fixing to the outer end portion thereof via the rolling bearing 38 and the fluid coupling 39. On the other hand, the impeller 34 and the bearing unit 31 are provided at a part of the rotary shaft 30.
A mechanical seal 40 is provided between the portion between and and the housing 33 so that the cooling water flowing through the housing 33 does not enter the bearing unit 31 side. Further, in order to prevent the cooling water that has entered the bearing unit 31 side beyond the mechanical seal 40 from entering the bearing unit 31, the inner end of the bearing unit 31 (the right end of FIGS. 3 to 4). A sealing device 12a as shown in FIG. 4 is provided in the opening.

The sealing device 12a is provided with a seal ring 17a composed of a core metal 15a and a sealing member 16a each formed in an annular shape, and a slinger 18a also formed in an annular shape. The core metal 15a constituting the seal ring 17a is formed into an annular shape by subjecting a metal plate such as a low carbon steel plate to punching such as press working and plastic working. In addition, the seal member 16a
Is made of an elastic material such as an elastomer such as rubber. The seal member 16a is fixed to the core metal 15a by molding the core metal 15a in the cavity of the molding die. Such a seal member 16a includes two outer seal lips 41 and 42 and one inner seal lip 43. Then, the sealing member 16a
The outer circumferential edge of the bearing is locked in a locking groove 45 provided on the inner peripheral surface of the inner end portion of the outer ring 44, which is the stationary member constituting the bearing unit 31, over the entire circumference without any gap. is doing.

The slinger 18a is the slinger 18 described in the first example of the above-described embodiment (see FIGS. 1 and 2).
Similarly, a stainless steel plate, a stainless steel plate plated with corrosion resistance, or a cold-rolled steel plate coated with corrosion resistance, such as a metal plate with excellent corrosion resistance against corrosion by water, oil, muddy water, etc. Alternatively, it is composed of a stainless steel plate subjected to corrosion-resistant plating. Such a slinger 18a includes an inner diameter side cylindrical portion 21a which can be externally fitted and fixed to the outer peripheral surface of the inner end portion of the rotating shaft 30 which is a rotating side member, and an inner end edge of the inner diameter side cylindrical portion 21a (right end in FIG. 4). Rim) and an outer circular ring portion 22a bent inward in the diametrical direction, and a second inner diameter side that is bent substantially outward from the outer end edge of the outer circular ring portion 22a in the axially outward direction (left in FIG. 4). And a cylindrical portion 46, which is substantially U-shaped in cross section and has an annular shape as a whole. Then, the second outer seal lip 42 and the inner seal lip 43 of the three seal lips 41, 42, 43.
Is slidably contacted with the inner diameter side cylindrical portion 21a and the outer peripheral surface of the rotary shaft 30, and the first outer seal lip 41 is slidably contacted with the outer peripheral surface of the second inner diameter side cylindrical portion 46.

Also in this example, the slinger 18 is used.
Of the outer peripheral surface of a, each of the seal lips 41, 42, 4
The surface roughness of the sliding contact surface with which 3 slidably contacts, that is, the surface roughness of the outer peripheral surface of the second inner diameter side cylindrical portion 43, which is the same as the outer peripheral surface of the inner diameter side cylindrical portion 21a that constitutes this slinger 18a, is the center line average roughness ( Ra) of 0.3 μm or less and the maximum height (R
y) is 1.2 μm (more preferably 0.8 μm) or less. The surface roughness of the outer peripheral surface of the rotary shaft 30 axially outward from the slinger 18a, that is, the portion where the inner seal lip 43 is in sliding contact, is preferably limited to the above range. Other configurations and operations are
Since it is the same as the case of the first example described above, the description of the equivalent parts will be omitted.

[0031]

EXAMPLES In order to confirm the effects of the present invention, the tests conducted by the present inventor will be described. This test is based on FIG.
The sealing device 12a shown in FIG. 2 is used, and as described in the following Table 1, the sealing device (Examples 1 to 4) configured by the slinger 18a according to the present invention, and the slinger (slinger 18a which deviates from the present invention. A sealing device (comparative example 1) having the same shape as the above but having a large surface roughness
The sealability evaluation of 2) was performed.

[0032]

[Table 1]

FIG. 5 shows a test apparatus used for the main test. The test apparatus has a housing 47, a support frame 48, and a lid 49. Housing 4 of these
A bearing unit 31 for rotatably supporting a rotary shaft 30 of a water pump 29 (see FIG. 3) is fixed to be internally fittable. The bearing unit 31 is composed of an outer ring 44 which is a stationary member, a plurality of balls 50 and 50 which are rolling elements, rollers 51 and 51, and the rotary shaft 30 which is a rotating member. Outer ring 46 of these is
A first outer ring raceway 52 having an arcuate cross section is provided at a portion near one end (right end in FIG. 5) of the inner peripheral surface, and a cylindrical second outer ring raceway 53 is similarly provided at a portion near the other end (left end in FIG. 5). Each is formed. Further, the rotary shaft 30 has a first inner ring raceway 54 having an arcuate cross section at a portion facing the first outer ring raceway 52 at an intermediate portion of an outer peripheral surface, and also faces the second outer ring raceway 53. The second inner ring raceways 55 each having a cylindrical shape are directly formed in the portions. Also, each ball 50, 50 and each roller 5
1, 51 are provided between the first outer ring raceway 52 and the first inner ring raceway 54 and between the second outer ring raceway 53 and the second inner ring raceway 55, respectively. It is provided so that it can roll freely. In this state, the rotary shaft 30 is rotatably supported by the housing 47.

Further, the outer ring 44 has a locking groove 45 formed on the inner peripheral surface of one end portion over the entire circumference, and the sealing device 12 for evaluation.
The outer peripheral edge of the seal member 16a that constitutes a is freely engageable over the entire circumference without a gap. Also, the rotating shaft 30
Is a slinger 18a constituting the sealing device 12a at a portion of the inner peripheral surface of the intermediate portion which is aligned with the sealing member 16a.
Is externally fitted and fixed, and the driven pulley 35a is joined and fixed at one end. An endless belt 36a is laid between the driven pulley 35a and a drive pulley (not shown) so that the rotary shaft 30 can be driven to rotate. The support frame 48 is fixed to the upper surface of the support base 56 and has a support portion 57 protruding upward. The housing 47 and the lid 49 can be fixedly connected to both side surfaces of the support portion 57.

Further, the supporting portion 57 is provided with a through hole 58 in a state of penetrating both side surfaces thereof. Then, the housing 47 is coupled and fixed to the side surface on the other end side (left side in FIG. 5) of the support portion 57, and the rotary shaft 30 is penetrated through the housing 47 while the bearing unit 31 is fitted and fixed therein. It passes through the hole 58. Further, the lid 49 is provided on the side surface on one end side (right side in FIG. 6) of the support portion 57.
Is fixed to the circular hole 59 provided in the central portion of the lid 49 with the rotary shaft 30 penetrating therethrough, thereby closing the one end side opening of the through hole 58. Then, the cooling water of the same quality as the cooling water for the automobile can be sent toward the sealing device 12a through the cooling water introducing pipe 60 provided in the lid 49. Then, the cooling water sent toward the sealing device 12a in this way passes through the through hole 58.
Inner surface, one side surface of the housing 47, and the lid 4
The cooling water is stored in the cooling water storage space 61 constituted by the other side surface 9 and the sealing device 12a. In order to freely supply the cooling water to the sealing device 12a in this manner, a metering pump (not shown) is provided at the upstream end of the cooling water introducing pipe 60, and a certain amount of cooling water is supplied through the metering pump. , And can be supplied to the sealing device 12a.

The rotary shaft 30 and the support frame 4 are also provided.
An electric circuit 62 is formed between the rotating shaft 30 and the supporting frame 48 so that the electric resistance between the rotating shaft 30 and the supporting frame 48 can be measured freely. Further, a heater 63 is provided on the outer peripheral surface of the housing 47 to allow the housing 47 to be heated, and a temperature sensor 64 such as a thermocouple is provided in a through hole provided so as to penetrate both the inner and outer peripheral surfaces of the housing 47. The temperature of the outer ring 44 fitted in the housing 47 can be measured freely. Then, the test apparatus configured as described above is operated under the following conditions, and every 100 hours of operation time,
The amount of water contained in the grease in the bearing unit 31 is measured, and when the amount of water contained in the grease reaches 5%, the sealability becomes abnormal and the bearing unit 3
Assuming that there was a problem with No. 1, the time until reaching it was calculated. Test conditions Heating temperature (temperature of outer ring 44): 100 ° C Rotating speed of rotating shaft 30: 2000min ^-1

The results of the tests are shown in Table 2 below. The sealing member 16a constituting the sealing device 12a is made of acrylonitrile butadiene rubber (NBR) to which carbon black as a reinforcing agent, other vulcanizing additive, antiaging agent and the like are added. Then, the rubber material composition having such a structure was kneaded and then adhered to the core metal 15a (see FIG. 4) together with vulcanization to bond the core metal 15a and the seal member 16a.

[Table 2]

In Table 1, "Nif Grip No.
"2" is the surface treatment (plating) technology of ULVAC TECHNO. Specifically, stainless steel (SUS4
30), electroless nickel and PTFE (polytetrafluoroethylene) were co-deposited in the treatment liquid to contain 20% by volume of PTFE in the nickel plating film, and heat treatment was performed after film formation. It is a plating treatment in which nickel and PTFE are firmly adhered. Further, in Table 2 above, the relative time of each Example and Comparative Example is that the water content in the grease is 5
The time to reach% is shown as a relative value with Comparative Example 1 being 1.0.

As is clear from Table 2 above, according to the sealing device (Examples 1 to 4) belonging to the present invention, compared with the sealing devices (Comparative Examples 1 and 2) which are not included in the present invention, The time for the water content to reach 5% can be doubled or longer. In particular, Example 4 in which the center line average roughness was 0.3 μm
Is a comparative example 1 in which the center line average roughness is 0.4 μm.
Compared with, the sealing property is significantly improved (the value of 0.3 μm has a boundary meaning). Further, in the case of Examples 2 and 3 in which the surface roughness is smaller than that in Example 4, the sealing property is improved as the surface roughness is reduced. Furthermore, in Example 1, since electroless nickel plating containing PTFE having a water-repellent effect was applied, invasion of water was suppressed and sealing performance was further improved as compared with Example 2 in which this corrosion resistant plating was not applied. Can be improved.

[0040]

Since the sealing device of the present invention is constructed and operates as described above, it is an excellent seal even when used in a severe environment where it is exposed to foreign matter such as water, oil, muddy water, and dust. Performance can be secured. For this reason, it is possible to contribute to the improvement of performance centering on durability of the rolling bearing device used in such a severe environment.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first example of an embodiment of the present invention.

FIG. 2 is a partially enlarged sectional view showing a sealing device incorporated in the right end portion of FIG.

FIG. 3 is a sectional view showing a second example of the embodiment of the present invention.

FIG. 4 is an enlarged vertical sectional view of a portion A of FIG. 3 with a part omitted.

FIG. 5 is a sectional view showing a test apparatus.

[Explanation of symbols]

1 outer ring 2 Mounting part 3 Inner ring equivalent member 4 hubs 5 inner ring 6 spline holes 7 Mounting flange 8 Outer ring track 9 Inner ring track 10 rolling elements 11 cage 12, 12a Sealing device 13 Seal ring 14 space 15, 15a core metal 16, 16a Seal member 17, 17a Seal ring 18, 18a slinger 19 Outer diameter side cylindrical part 20 Inner ring part 21, 21a Inner diameter side cylindrical part 22, 22a Outer ring part 23 Outer seal lip 24 Intermediate seal lip 25 inner seal lip 26 core 27 Seal member 28a, 28b, 28c Seal lip 29 Water pump 30 rotation axis 31 Bearing unit 32 cooling fan 33 housing 34 Impeller 35, 35a driven pulley 36, 36a Endless belt 37 Inner hub 38 Rolling bearing 39 Fluid coupling 40 mechanical seal 41 First Outer Seal Lip 42 Second Outer Seal Lip 43 Inner seal lip 44 outer ring 45 locking groove 46 Second inner diameter side cylindrical portion 47 housing 48 support frame 49 Lid 50 balls Around 51 52 First outer ring raceway 53 Second outer ring raceway 54 First inner ring raceway 55 Second inner ring raceway 56 Support 57 Support 58 through hole 59 circular hole 60 Cooling water introduction pipe 61 Cooling water storage space 62 electric circuit 63 heater 64 temperature sensor

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takahiko Uchiyama             1-5-50 Kumei, Kugenuma, Fujisawa-shi, Kanagawa             Within NSK Ltd. F-term (reference) 3J006 AE23 AE34                 3J016 AA02 AA03 BB03

Claims (3)

[Claims] 1. A stationary bearing member, which is located between a peripheral surface of a rotary member and a stationary member of a rolling bearing device and closes an end opening of a space in which a plurality of rolling elements are installed. The seal ring held by the side member and the slinger fixed to the rotating side member are provided, and the tip edge of the seal lip made of an elastic material forming the seal ring is slidably contacted with the surface of the slinger over the entire circumference. In the above sealing device, the surface roughness of at least a portion of the surface of the slinger that is in sliding contact with the seal lip is 0.3 μm or less in the center line average roughness and 1.2 μm in the maximum height. Sealing device characterized by the following. 2. The sealing device according to claim 1, wherein the slinger is a metal plate plated with corrosion resistance. 3. The sealing device according to claim 2, wherein a solid lubricant is contained in the corrosion resistant plating.