JP2003254340A - Bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the generation of fretting in an abutment surface between an inner ring and a fixed ring in a bearing device for supporting an axle of a railway vehicle. <P>SOLUTION: In this bearing device 2, a wheel side inner ring 11b of a rolling bearing 3 is made to abut on a free end side end surface 30 of a rear cover 9 for positioning, and the free end side end surface 30 of the rear cover 9 is coated with a diamond-like carbon film 19 having excellent smoothness and abrasion resistance. With this structure, abrasion and damage of the diamond- like carbon film 19 is hard to be generated, and a coefficient of friction in the abutment surface between the rear cover 9 and the wheel side inner ring 11b can be reduced to prevent the generation of fretting. <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 bearing having a rolling bearing which is externally mounted on a rotary shaft and a fixed ring which is externally fitted and fixed to the rotary shaft to position the inner ring of the rolling bearing with respect to the rotary shaft. Regarding the device.

[0002]

2. Description of the Related Art The structure of a bearing device used to support a vehicle body on an axle of a railway vehicle will be described. The conventional bearing device is
A double row outward rolling bearing is provided. This rolling bearing consists of a single outer ring, two inner rings, a double row tapered roller group interposed between the outer ring and both inner rings in two rows, and a roller group in each row between the outer ring and both inner rings. And two retainers for supporting the. The vehicle body is fixed to the outer ring. Both inner rings are mounted axially adjacent to the journal portion of the axle.

A front lid is fixed to the free end side of the journal portion of the axle. The rear lid is fixed to the wheel side of the journal part of the axle. Both inner rings of the rolling bearing are fixed to the journal portion of the axle by a front lid and a rear lid so as to be fixed axially in the axial direction. In this case, both end surfaces of the wheel-side inner ring of the rolling bearing and the rear lid are in direct contact with each other.

[0004]

As the railway vehicle travels, the axle is subject to radial and axial loads and impacts, and vibrates. As a result, a slight deflection is generated on the axle and a slight relative movement with respect to the rolling bearing occurs. In this case, both the wheel-side inner ring and the rear lid are made of a metal material.
Therefore, when the deflection and the minute relative movement are repeated, the contact surfaces of the wheel-side inner ring and the rear lid are rubbed with each other,
So-called fretting occurs and metal abrasion powder is produced. Such metal wear powder mixes with the lubricant to accelerate the deterioration of the lubricant, or to get caught in the rolling surface of the rolling bearing to accelerate the wear of the rolling bearing, thereby shortening the life of the bearing device.

Therefore, the problem to be solved by the present invention is to provide a rolling bearing which is externally mounted on a rotary shaft, and a fixed ring which is externally fitted and fixed to the rotary shaft to position the inner ring of the rolling bearing with respect to the rotary shaft. In the bearing device having the above, it is possible to suppress the occurrence of fretting due to the friction between the contact surfaces of the inner ring and the fixed ring provided in the rolling bearing.

[0006]

According to a first aspect of the present invention, there is provided a rolling bearing which is externally fitted to and fixed to the rotary shaft and which is externally fitted to the rotary shaft. A bearing device having a fixed ring for abutting an inner ring provided to position the inner ring with respect to the rotary shaft, wherein one of the contact surfaces of the inner ring of the rolling bearing and the fixed ring is provided. The chromium film, the tungsten carbide film, and the diamond-like carbon film are laminated and provided.

The rotating shaft is a rotating shaft or a shaft that can be rotated, and is not limited to the axle of the embodiment and may be any shaft or shaft-like structure as long as it is rotatable.

The rolling bearing is not limited to the rolling bearing having the two inner rings axially adjacent to the rotating shaft like the double row outward rolling bearing of the embodiment, but the rolling bearing having a single inner ring. Also includes.

The diamond-like carbon film is an amorphous hard carbon film mainly composed of carbon and hydrogen. Since it has an amorphous structure, it has properties similar to those of diamond. Compared to other hard films, it is extremely hard and has excellent wear resistance, and it has excellent anti-adhesion properties such as low opponent attack. Further, the diamond-like carbon film has an extremely smooth film surface.

In the bearing device of the present invention, since the diamond-like carbon film is provided on one of the contact surfaces of the inner ring and the fixed ring, even if the contact surfaces of the fixed ring and the inner ring are repeatedly rubbed against each other. Abrasion of both contact surfaces is suppressed. As a result, it is possible to suppress the occurrence of fretting due to the rubbing of both contact surfaces.

In addition, since the coating is provided via the chromium-containing film as the base film, the bonds between the atoms of each film are strengthened, and the hard film is attached to one surface of the contact surface between the fixed ring and the inner ring. Can be firmly adhered to. Along with this, since the tungsten-carbide film is interposed between the diamond-like carbon film and the chromium film, the bond between the atoms to be covered becomes stronger and the diamond-like carbon film is fixed. It can be firmly adhered to one surface of the contact surface between the inner ring and the inner ring.

Therefore, the bearing device of the present invention is applied as a rotating shaft to an axle of a railroad vehicle, mounted on the axle, and the contact surface between the inner ring of the rolling bearing and the rear lid fixed to the axle as the fixed ring is rubbed. It is possible to effectively suppress the occurrence of fretting due to matching. Therefore, it is possible to suppress the generation of metal abrasion powder due to the rubbing of both abutting surfaces to reduce the abrasion rate of the rolling bearing, and it is also possible to prevent the metal abrasion powder from mixing with the lubricant and deteriorating the lubricant. As a result, it is possible to extend the life of the bearing device applied to the axle of the railway vehicle.

In the present invention, preferably, the diamond-like carbon film has a film thickness of 1.
It has a thickness of 0 to 5.0 μm, and its adhesion to the coating object is set to at least 40N.

If the thickness of the diamond-like carbon film is less than 1.0 μm, the wear resistance is insufficient and 5.0 μ
If it exceeds m, not only the cost becomes enormous, but also the internal stress becomes large due to the excessively large film thickness, which causes peeling. Further, when the adhesion of the diamond-like carbon film to the coating object is less than 40 N, the coating film is likely to peel off.

In such a case, it is possible to obtain a diamond-like carbon film which is excellent in smoothness and wear resistance in addition to the above-mentioned effects. In this case, the thickness of the diamond-like carbon film is more preferably 1 to 5
μm, optimally 3 μm.

More preferably, in the present invention, as shown in claim 3, the total thickness of the chromium film, the tungsten carbide film, and the diamond-like carbon film is 1.5 to 3. 0 μm, and the roughness of the diamond-like carbon film surface is the center line average roughness (R
It is controlled to 0.1 μm or less in a).

If the total film thickness is less than 1.5 μm, the abrasion resistance is insufficient, and if it exceeds 3.0 μm, not only the cost becomes enormous, but also the internal stress due to the excessive film thickness is large. It may cause peeling. Further, if the hardness is less than 1000 in Vickers hardness (Hv), the abrasion resistance is insufficient, and if it exceeds 2000, the internal stress becomes large and causes peeling.

In the present invention, more preferably, the diamond-like carbon film contains tungsten.

In such a case, in addition to the above-described effects, since the diamond-like carbon film contains tungsten, the bond between atoms and the object to be coated becomes stronger, and the diamond-like carbon film is fixed to the fixed ring and the inner ring. Can be firmly adhered to one surface of the contact surface with. Further, since tungsten is a metal element, the conductivity of the diamond-like carbon film is improved, which makes it suitable for use under the condition where the conductivity is required.

[0020]

DETAILED DESCRIPTION OF THE INVENTION The details of the present invention will be described below with reference to the embodiments shown in the drawings.

Embodiment 1 is shown in FIGS. 1 to 3. Figure 1
1 is a sectional view showing a bearing device according to a first embodiment of the present invention and a supporting portion of an axle of a railway vehicle to which the bearing device is applied, FIG. 2 is an enlarged sectional view of a main part of FIG. 1, and FIG. It is an expanded sectional view which shows the coating structure of the end surface by the side of the free end of a rear lid.

Referring to these figures, 1 is an axle, 2 is
Indicates a bearing device.

A wheel (not shown) is attached to the right side of FIG. 1 as a rotating shaft of the axle 1.

The bearing device 2 includes a rolling bearing 3 and a front lid 4.
An oil draining sleeve 5, a plurality of bolts 6, sealing devices 7 and 8, and a rear lid 9.

The rolling bearing 3 serves as a so-called double row outward tapered roller bearing arranged outward, and is attached to the journal portion 21 of the axle 1.

The rolling bearing 3 also includes a single outer ring 10,
Two inner rings 11a, 11 arranged axially side by side
b, a double row tapered roller 12 as a rolling element arranged between the inner and outer rings 10, 11a, 11b, and a retainer 13 for the tapered roller 12.

In the rolling bearing 3, the outer ring 10 is the vehicle body.
It is fixed to (not shown). Each inner ring 11a, 1
1b is axially sandwiched by the front lid 4 and the rear lid 9 via the spacer 14. The entire rolling bearing 3 is composed of the inner rings 11a,
It is fixed immovably in the axial direction by the holding structure of 11b.

In this case, the front lid 4 and the rear lid 9 are arranged on the outer periphery of the journal portion 21 of the axle 1 on both sides in the axial direction of the rolling bearing 3. Specifically, the front lid 4 is on the free end side end surface of the inner ring 11a on one side (the free end side of the journal portion 21 of the axle 1) via the oil draining sleeve 5, and the rear lid 9 is on the other side inner ring 11b. It directly abuts on the wheel-side end surface (on the base side of the journal portion 21 of the axle 1). As a result, the front lid 4 and the rear lid 9 both function as an annular fixed ring that fixes the rolling bearing 3 immovably in the axial direction, in addition to the function of the lid.

In this case, the front lid 4 is attached to the free end side of the journal portion 21 by tightening the bolt 6 with a predetermined torque, and is attached to the free end side of the inner ring 11a via the oil draining sleeve 5. It is in contact with the end face.

Further, the rear lid 9 has a structure integrated with the oil draining sleeve. However, the rear lid 9 may be brought into contact with the wheel-side end surface of the inner race 11b via the oil draining sleeve 5 in the same manner as the front lid 4 side.

Both sealing devices 7 and 8 are arranged on the outer peripheral surfaces of the oil removing sleeve 5 and the rear lid 9, respectively, on both axial sides of the rolling bearing 3.

Both sealing devices 7 and 8 seal a required sealing area including both end portions of the rolling bearing 3, thereby preventing muddy water, dust and the like from entering the inside of the rolling bearing 3 from the outside. To be done.

In the drawing, the sealing area 3 on the sealing device 8 side is shown.
1 is shown enlarged in FIG. 2, the sealing region on the side of the sealing device 7 also has a similar structure.

The first embodiment of the present invention is characterized by having the following configuration.

That is, the diamond-like carbon (Diamond) is attached to the end surface 30 of the rear lid 9 on the free end side.
-Like carbon (DLC) film 91 is covered.

In order to ensure the adhesion of the diamond-like carbon film 91 to the base material (end surface of the rear lid 9 on the free side) in this coating, it is preferable that a chromium (Cr) film 92 is previously formed on the rear lid 9 as a base film. The end face 30 on the end side is covered.

The chromium film 92 is covered with a diamond-like carbon film 91. However, the chromium film 92 is not essential, and the diamond-like carbon film 91 may be directly coated on the end surface 30 of the rear lid 9 on the free end side.

The thickness of the diamond-like carbon film 91 is controlled to 1.0 to 5.0 μm.

The adhesion to the object on which the diamond-like carbon film 91 is formed is at least 40 N, preferably 6
Managed to 0N.

The diamond-like carbon film 91 has a graphite structure (SP ² ) and a diamond structure (bonding:
SP ³ ) coexists with each other, the carbon atoms constituting them are strongly bonded to each other, and they themselves are hard and have excellent surface smoothness.

Therefore, by forming the diamond-like carbon film 91 on the end surface 30 of the rear lid 9 on the free end side, the diamond-like carbon film 91 itself is less likely to be worn or damaged, and the inner ring 11b and the rear lid 9 are prevented.
It is possible to reduce the friction coefficient on the contact surface with and to prevent fretting.

Further, the diamond-like carbon film 91
Since the chromium film 92 is provided as a base film of the above, the bonds between the atoms of the respective films are strengthened, and the diamond-like carbon film 91 excellent in smoothness and wear resistance is firmly adhered to the rear lid 9. be able to. Therefore, the diamond-like carbon film 91 is less likely to be peeled off, durability is improved, and reliability can be greatly improved.

The diamond-like carbon film 91 and the chromium film 92 are formed by physical vapor deposition (P
VD) method, chemical vapor deposition (CVD) method, plasma CVD method,
It can be formed by an ion beam forming method, an ionization vapor deposition method, or the like.

Among them, the sputtering method, which is one of the PVD methods, is a coating method utilizing a physical mechanism, and therefore has a feature that high adhesion can be ensured regardless of the material of the underlying layer.

Therefore, here, a sputtering method is selected, and a generation process by the same method will be described. At that time, the chromium film 92 and the diamond-like carbon film 91 are sequentially formed in this order.

First, in forming the chromium film 92, chromium is used as a target and argon gas is used as an introduction gas. Then, the chamber pressure is set to 10
^-3 to 10 [Torr] and discharge voltage 100 to 2k
The discharge treatment is performed at [V] and a current of 0.5 to 5.0 [A]. As a result, the chromium film 9 is formed on the surface of the end surface 30 of the rear lid 9.
2 is formed with a thickness of 0.4 to 0.6 μm.

Next, the diamond-like carbon film 91
In producing the gas, an argon gas, a hydrocarbon gas, or the like is used as an introduction gas, and the discharge voltage is 100 to 2 k.
The discharge treatment is performed at [V] and a current of 2 to 10 [A]. As a result, the diamond-like carbon film 91 made of amorphous carbon is formed on the chromium film 92.

In this way, in order to form the chromium film 92 or the diamond-like carbon film 91 on a part of the target component, masking may be applied appropriately.

The diamond-like carbon film 91
The abrasion resistance (smoothness) and the adhesiveness of No. 1 will be described because they are respectively tested.

First, the diamond-like carbon film 91
The test for the abrasion resistance (smoothness) will be described.

The test was conducted on the examples according to the present invention and the comparative examples. In the example, a JIS standard SUS440C circular plate coated with the diamond-like carbon film 91 was used as a sample.

In the comparative example, an uncoated JIS standard SU is used.
A circular plate of S440C was used as a sample.

As a test method, a plurality of metal balls were circumferentially arranged and pressed at the eccentric positions of the circular plates of the above-mentioned examples, and each circular plate was rotated while being pressed. The ball is
Made of SUJ2 material with a diameter of 5/32 inch, surface pressure 1.0
By pressing under the strong pressing force of GPa, the circular plate slides non-rotatingly with respect to the rotation. When the circular plate of each sample was rotated, the sliding speed with respect to the ball was 0.
It is controlled so that the sliding distance is 1 m / s and the sliding distance is 360 m.

[0054]

[Table 1] As a result, as shown in Table 1 above, both the friction coefficient and the wear scar diameter of the example were reduced to 1/3 or less of those of the comparative example, and excellent abrasion resistance and smoothness were obtained. It turned out that

Next, the diamond-like carbon film 91
The test for the adhesiveness of is described.

The test was conducted on the examples according to the present invention and the comparative examples. In the embodiment, JIS standard SUS440 is used.
A substrate of C was coated with a diamond-like carbon film 91 via a chromium film 92 as a base film, which was used as a sample.

In the comparative example, JIS standard SUS440C is used.
A substrate obtained by coating the diamond-like carbon film 91 with a silicon film as a base film interposed therebetween was used as a sample.

In the embodiment, the diamond-like carbon film 91 is controlled to have a thickness of 3 μm and an adhesion force of 60N. In the comparative example, the diamond-like carbon film 91
The thickness is controlled to 2 μm and the adhesion is controlled to 5N.

As a test method, under oil bath lubrication,
A plurality of metal balls were arranged in the circumferential direction at the eccentric positions of the circular plates of each of the above examples and pressed while the circular plates were rotated. The ball is made of SUJ2 material with a diameter of 5/32 inch. The pressing force is 1.6 GPa, 2.1 GPa, 3.
Three types of 4 GPa were set, and each was tested. Under each of these pressing forces, the ball rolls on the circular plate. The circular plate of each sample is controlled at 1200 rpm and
0 ⁸ broke off test when rotated.

[0060]

[Table 2] As a result, as shown in Table 2 above, in the comparative example, even when the pressure of the ball was 1.6 GPa, peeling of the coating had already occurred at less than 10 ⁷ revolutions, and 2.1 GPa and 3.4 GPa.
In, the life is further reduced to 10 ⁶ rotations or less.

On the other hand, in the examples, no sign of peeling, abrasion or the like could be found even if the ball was pressed for 10 ⁸ times at any pressing force, and it was proved that the ball had excellent adhesion.

FIG. 4 is an enlarged sectional view showing a covering structure of the end surface on the free end side of the rear lid according to the second embodiment of the present invention.

The second embodiment is characterized in that a diamond-like carbon film 93 containing tungsten is formed on the end surface 30 of the rear lid 9 on the free end side via a chromium film 92 as a base film. That is the coating.

In this embodiment, the diamond-like carbon film 93 containing tungsten is abbreviated as the W-diamond-like carbon film 93.

In this case, the W-diamond-like carbon film 93 is set to a composition in which the amount of tungsten is abundant toward the chromium film 92 side. As a result, the amount of carbon becomes richer toward the surface side.

By the way, the W-diamond-like carbon film 93 and the chromium film 92 are formed, for example, by physical vapor deposition (PVD) method, chemical vapor deposition (CVD) method, plasma CVD.
Method, ion beam forming method, ionization vapor deposition method, or the like.

Here, for the same reason as in Embodiment 1 above, a sputtering method, which is one of the PVD methods, is selected,
The generation process by the same method will be described. At that time, the chromium film 92 and the W-diamond-like carbon film 93 are sequentially formed in this order. However, the process of forming the chromium film 92 has already been described, and thus the description thereof will be omitted.

In forming the W-diamond-like carbon film 93, tungsten carbide (WC) or tungsten is used as a target, and argon gas or hydrocarbon gas is used as an introduction gas.

Then, the pressure in the chamber is set to 10 ^-3 to 10
About [Torr], and discharge processing is performed. During the coating, the amount of carbon gas is increased by increasing the amount of hydrocarbon gas or shielding the target with a shutter.

By the way, the total thickness of the W-diamond-like carbon film 93 and the chromium film 92 serving as a base film is controlled to, for example, about 1.5 to 3.0 μm, and the hardness is Vickers hardness. 1000 (Hv) to 20
00, and the roughness of the outermost surface is the centerline average roughness.
(Ra) is controlled to 0.1 μm or less.

In the bearing device 2 described above, since the end surface 30 of the rear lid 9 on the free end side is covered with the W-diamond-like carbon film 93 having excellent smoothness and wear resistance, the inner ring 11b and the rear ring 11b are not covered. Even if a lubricating component such as grease is not present at the contacting portion with the lid 9, its smoothness and wear resistance are maintained well, and the aggressiveness to the inner ring 11b can be suppressed low. Therefore, the occurrence of so-called fretting can be reduced, and the life of the bearing device 2 can be improved.

Since the W-diamond-like carbon film 93 covers the rear lid 9 as the base material via the chromium film 92 as the base film, the interatomic bond between the respective films is increased. Of the W-diamond-like carbon film 93, which is strong and has excellent smoothness and wear resistance, can be firmly adhered to the rear lid 9 to cover it. Therefore, the W-diamond-like carbon film 93 is less likely to be peeled off, durability is improved, and the reliability can be greatly improved.

Further, since the W-diamond-like carbon film 93 contains tungsten and is set to have a composition in which the amount of tungsten is abundant toward the object to be coated, the W-diamond-like carbon film 93 has an interatomic relationship with the object to be coated. It keeps the bond strong. On the other hand, since the amount of tungsten decreases toward the front surface side, the amount of carbon is relatively increased, and the smoothness and wear resistance of the surface of the W-diamond-like carbon film 93 are maintained.

Further, since the W-diamond-like carbon film 93 contains tungsten which is a metal element, the W-diamond-like carbon film 93 and the rear lid 9 have electrical conductivity. Thus, it becomes suitable for use under the condition where electrical conductivity is required, such as a bearing device for supporting an axle of a railroad vehicle, particularly a train.

FIG. 5 is an enlarged cross-sectional view showing the covering structure of the end surface on the free end side of the rear lid according to the third embodiment of the present invention.

The feature of the third embodiment is that
The tungsten carbide film 9 is formed on the end surface 30 on the free end side of the rear lid 9 with a chromium film 92 as a base film interposed therebetween.
5 and the diamond-like carbon film 91 are laminated and covered in this order.

In this embodiment, as shown in FIG. 5, the tungsten-carbide film 95 and the diamond-like carbon film 91 are alternately provided on the diamond-like carbon film 91 in this order. Several layers are stacked, and the thickness of each tungsten carbide film 95 is set to be gradually thinner from the object to be coated toward the front surface side. On the other hand, the thickness of each diamond-like carbon film 91 is set to be gradually thicker from the object to be coated toward the front surface side.

The chromium film 92, the tungsten carbide film 95, and the diamond-like carbon film 91.
Also, for example, it can be formed by a physical vapor deposition (PVD) method, a chemical vapor deposition (CVD) method, a plasma CVD method, an ion beam forming method, an ionization vapor deposition method, or the like.

Here, a sputtering method, which is one of PVD methods, is selected for the same reason as in the first embodiment.
The generation process by the same method will be described. At that time, the chromium film 92 and the tungsten / carbide film 95 are formed.
And the diamond-like carbon film 91 are sequentially formed in this order. However, the process of forming the chromium film 92 has already been described, and thus the description thereof will be omitted.

First, in forming the tungsten carbide film 95, tungsten carbide or tungsten is used as a target, and argon gas is used as an introduction gas. Then, the chamber internal pressure is set to about 10 ⁻³ to 10 [Torr], and the discharge voltage is set to 200 to
Discharge treatment is performed at 700 [V] and a current of 2 to 10 [A]. As a result, the tungsten carbide film 95 is formed on the chromium film 92.

Next, the diamond-like carbon film 91
In producing the gas, an argon gas, a hydrocarbon gas, or the like is used as an introduction gas, and the discharge voltage is 200 to 700.
The discharge treatment is performed at [V] and a current of 2 to 10 [A]. As a result, the diamond-like carbon film 91 made of amorphous carbon is formed on the tungsten carbide film 95.

After that, the diamond-like carbon film 9
As shown in FIG. 5, the tungsten carbide film 95 and the diamond-like carbon film 91 are alternately laminated on the first layer 1 by a required number. At this time, each tungsten
The thickness of the carbide film 95 is gradually reduced from the object to be coated toward the surface side, and the thickness of each diamond-like carbon film 91 is gradually increased from the object to be coated toward the surface side.

These films 92, 95, 91 do not form a boundary surface, but are diffused and bonded to each other at the atomic level.

In the bearing device 2 described above, like the diamond-like carbon film 91 shown in FIG.
Since the surface of the end surface 30 on the free end side of the rear lid 9 is composed of the diamond-like carbon film 91 having excellent smoothness and wear resistance, grease or the like may be applied to the contact portion between the inner ring 11b and the rear lid 9. Even if the lubricating component is not present, its smoothness and wear resistance are kept good, and the aggressiveness to the inner ring 11b can be suppressed to a low level.

Therefore, the occurrence of so-called fretting can be reduced, and the life of the bearing device 2 can be improved.

Further, the diamond-like carbon film 91
And the tungsten / carbite film 95 are coated on the rear lid 9 as a base material via the chromium film 92 as a base film, the bonds between the atoms of each film become strong and smooth. The diamond-like carbon film 91 having excellent properties and abrasion resistance can be firmly adhered to the rear lid 9 to cover it.

As a result, the diamond-like carbon film 91 is less likely to be peeled off and durability is improved, which greatly contributes to reliability improvement.

The bearing device 2 shown in the above embodiment may be modified or applied as follows.

(1) In the above-described embodiment, the diamond-like carbon film 91 or the W-diamond-like carbon film 93 is formed on the end surface 30 of the rear lid 9 on the free end side. It may be formed on the entire outer surface or may be formed on the surface of the wheel-side end surface 32 of the inner ring 11b.

(2) The rolling bearing 3 of the bearing device 2 is a double row outward tapered roller bearing, but the present invention can be applied to a bearing device having other types of rolling bearings.

[0091]

As described above, according to the present invention, the diamond-like carbon film having excellent smoothness and wear resistance is formed on one of the contact surfaces of the inner ring and the fixed ring.
When the contact part between the fixed ring and the inner ring rubs slightly,
The diamond-like carbon film interposed in the abutting portion improves mutual smoothness and wear resistance,
It becomes possible to suppress the occurrence of fretting at the contact portion.

Therefore, unlike the conventional example, it is not necessary to generate the abrasion powder from the abutting portion, so that the abrasion powder can be prevented from being mixed into the inside of the rolling bearing, which contributes to the improvement of the life of the bearing device. Like

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a bearing device according to a first embodiment of the present invention and a support portion of an axle of a railway vehicle to which the bearing device is applied.

FIG. 2 is an enlarged cross-sectional view of the main part of FIG.

FIG. 3 is an enlarged cross-sectional view showing a covering structure of an end surface on the free end side of the rear lid of FIG.

FIG. 4 is an enlarged cross-sectional view showing a covering structure of an end surface on a free end side of a rear lid according to a second embodiment of the present invention.

FIG. 5 is an enlarged cross-sectional view showing a covering structure of an end surface on a free end side of a rear lid according to a third embodiment of the present invention.

[Explanation of symbols]

2 Bearing device 3 Rolling bearing 9 Rear lid 11b Wheel side inner ring 91 Diamond-like carbon film 92 Chrome film 93 W-Diamond-like carbon film 95 Tungsten Carbide Film

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3J017 AA01 DA01 DB01                 3J101 AA13 AA25 AA32 AA43 AA54                       AA62 BA51 BA53 BA57 BA70                       DA05 EA43 EA47 EA78 FA35                       GA01 GA02

Claims (4)

[Claims] 1. A rolling bearing which is externally mounted on a rotary shaft, and an inner ring which is externally fitted and fixed to the rotary shaft and abuts on an inner ring provided on the rolling bearing to position the inner ring with respect to the rotary shaft. A bearing device having a fixed ring, wherein a chromium film, a tungsten / carbide film, and a diamond-like carbon film are laminated on one of both contact surfaces of the inner ring of the rolling bearing and the fixed ring. Bearing device that is installed. 2. The bearing device according to claim 1, wherein the diamond-like carbon film has a thickness of 1.0 to
A bearing device having a thickness of 5.0 μm and an adhesion force with respect to the coating target of which is set to at least 40N. 3. The bearing device according to claim 1, wherein the chromium film, the tungsten carbide film, and the diamond-like carbon film have a total film thickness of 1.5 to 3.0 μm. , A bearing device in which the roughness of the surface of the diamond-like carbon film is controlled to be 0.1 μm or less in terms of center line average roughness (Ra). 4. The bearing device according to claim 1, wherein the diamond-like carbon film contains tungsten.