JP2002181054A - Electrocorrosion preventive rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce cost by reducing working manhour and working hour by simplifying a spray process, obtaining an excellent electrical insulating property, close adhesion to a bearing ring of an insulating layer or a peeling preventive property at the time of fastening and fitting. SOLUTION: A coating layer 6 is provided from a peripheral surface 3a mounted on a housing 10 of an outer ring 3 over width surfaces 3b, 3c on both sides. The part 3a for covering the peripheral surface of the outer ring 3 in this coating layer 6 and parts 6a and 6b for covering a load side width surface 3b are made a two-layer structure or a three-layer structure laminating a ceramics insulating layer 8 and metallic layers 7 and 9. In a part 6c for covering a non-load side width surface 3c of the outer ring 3 in the coating layer 6, the number of laminated layers is smaller than that in the part 6a for covering the peripheral surface and an outermost layer is made as a ceramics insulating layer 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing used for a main motor, a drive unit, an axle, etc. of a railway vehicle, and an electric current flows inside the bearing due to the structure of a device in which the bearing is incorporated. TECHNICAL FIELD The present invention relates to an anti-corrosion type rolling bearing used for an application that requires prevention of rolling.

[0002]

2. Description of the Related Art Rolling bearings used for a main motor of a railway vehicle are designed such that when the current collector for grounding the current of the main motor to the ground from the wheels to the rail is incomplete, the current of the main motor is supplied to the inner and outer rings of the rolling bearing. And through a rolling element, it flows between a wheel and a rail. For this reason, a spark may be generated between the rolling element and the rolling surface of the outer ring, or between the rolling element and the rolling surface of the inner ring, so that so-called electrolytic corrosion may be caused to shorten the life of the bearing. For this reason, there has been proposed an outer ring in which a surface to be attached to a housing is covered with a resin insulating layer. However, the resin layer has a large coefficient of linear expansion, and an error occurs in fitting between the outer ring and the housing due to heat generated during operation of the bearing. As the insulating layer, ceramics are preferred because of their low coefficient of linear expansion and high electrical insulation, and a thermal sprayed ceramic layer has been proposed as the insulating layer. However, ceramics are not easily blended with the material of the bearing race, and are not easily sprayed, so that there is a problem in adhesion to the outer race. Further, when the outer ring is pressed into the housing, peeling may occur.

In order to solve such a problem, there has been proposed a structure in which a coating layer having a three-layer structure including a metal layer, an insulating layer of ceramics, and a metal layer is provided on a mounting surface of an outer ring to a housing (FIG. 1). For example, Japanese Utility Model Laid-Open No. 2-46119). Each layer is provided by thermal spraying. Of the above three layers,
The metal layer on the inner layer side is provided to improve the adhesion of the insulating layer because the ceramic of the insulating layer is not easily adapted to the material of the bearing race and is not easily sprayed. The metal layer on the outer layer side is provided such that when the outer ring is tightly fitted into the housing, the insulating layer is not easily peeled off at the time of press fitting.

[0004]

The insulating layer and the inner and outer metal layers each having a three-layer structure as described above can be obtained by thermal spraying. However, thermal spraying is an expensive process, and in the case of a bearing, if it has a three-layer structure as described above,
The cost of thermal spraying accounts for the majority of the production cost of the bearing, and the price of the bearing itself is very high. Further, in the case of the tapered roller bearing, if the three-layer structure is used as described above, there is a possibility that the sprayed layer on the large-diameter side width surface may be turned up during processing. In other words, in order to suppress the temperature rise of the base material bearing steel, cooling is performed simultaneously with air or the like at the time of spraying, but the sprayed material is also cooled, and the contraction force generated at this time loses the adhesion force with the base material. , Turning over occurs.

In order to reduce the above-mentioned thermal spraying cost, the present applicant has proposed a structure in which the entire coating layer has a two-layer structure (Japanese Patent Application No. 2000-236791). However, the situation such as the load acting on the place where the coating layer is provided on the raceway,
Each part is different. Therefore, when the entire coating layer has a two-layer structure, the effect of cost reduction is still insufficient compared with the processing cost and the obtained function.

SUMMARY OF THE INVENTION It is an object of the present invention to simplify the thermal spraying process while obtaining excellent electrical insulation and adhesion of an insulating layer to a raceway or preventing peeling at the time of interference fit, thereby reducing the number of processing steps,
An object of the present invention is to provide an anti-corrosion type rolling bearing capable of reducing the processing time and reducing the cost. Another object of the present invention is to prevent the thermal spray layer on the large-diameter side from being curled during machining in the case of a tapered roller bearing.

[0007]

According to the present invention, an anti-corrosion type rolling bearing is provided with a coating layer extending from a peripheral surface attached to a housing or a shaft of a race to a width surface on both sides. A portion covering the peripheral surface of the bearing member has a two-layer structure or a three-layer structure in which a ceramic insulating layer and a metal layer are laminated, and the portion covering the non-load-side width surface of the bearing ring in the covering layer is more than the portion covering the peripheral surface. It is assumed that the number of layers is small and the outermost layer is an insulating layer of ceramics. The portion covering the load-side width surface of the bearing ring has the same two-layer structure or three-layer structure as the portion covering the peripheral surface. As described above, the portion covering the non-load-side width surface of the bearing ring has a smaller number of layers than the portion covering the peripheral surface, that is, since a part of the sprayed layer is reduced, the spraying process is simplified accordingly, and the processing is performed. Man-hours and processing time can be reduced, and costs can be reduced. The number of sprayed layers is reduced in the area that covers the non-load side width surface of the raceway, and in the area where the number of layers is reduced, the outermost layer is a ceramic insulating layer. During handling such as joint work, there is no problem of insufficient strength of the coating layer, and electrical insulation is ensured. As described above, the reduction in the function of the coating layer is suppressed, and the cost can be reduced by reducing the number of sprayed layers.

In the present invention, a metal layer may be used as the outermost layer of the coating layer, which covers the outer diameter surface and the load-side width surface of the bearing ring. As described above, when the outermost layer on the outer diameter surface of the bearing ring is a metal layer, the insulating layer is prevented from peeling during press fitting when the bearing ring is tightly fitted to the housing or the shaft. If the outermost layer on the load-side width surface of the bearing ring is also a metal layer, axial loads and impacts do not directly act on the ceramic insulating layer, and damage to the insulating layer is prevented.

In the present invention, the bearing may be a tapered roller bearing. In the case of a tapered roller bearing, due to its structure, the width surface on the large diameter side becomes the non-load side width surface. In the tapered roller bearing, as described above, the coating layer on the large-diameter width surface is likely to be rolled up during thermal spraying. However, since the number of laminations on the large-diameter width surface is reduced, the winding is unlikely to occur.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. This anti-corrosion type rolling bearing 1
Has a plurality of rolling elements 5 held by a retainer 4 interposed between an inner ring 2 which is an inner and an outer race ring and an outer ring 3, and a coating layer 6 is provided on the outer ring 3. This bearing comprises a tapered roller bearing, the inner ring 2 has flanges 2a and 2b on both sides, and the outer ring 3
Is assumed to have no collar. The rolling elements 5 are formed of tapered rollers.

The coating layer 6 of the outer race 3 is provided from the outer peripheral surface attached to the housing 10 to the width surfaces 3b and 3c on both sides. As shown in FIG. 3A in an enlarged manner, a portion 6a covering the outer peripheral surface 3a of the outer ring 3 and a portion 6b covering the load-side width surface 3b in the covering layer 6 have a metal layer 7 as the innermost layer and a ceramic layer as the intermediate layer. Has a three-layer structure in which an insulating layer 8 and an outermost layer are metal layers 9. The portion 6c of the coating layer 6 that covers the non-load-side width surface 3c of the outer ring 3 has a smaller number of layers by one layer than the portion 6b that covers the outer peripheral surface, and the inner layer is a metal layer 7 and the outer layer is a ceramic insulating layer 8. I have. That is, the portion 6c that covers the non-load-side width surface 3c is the other portion 6c.
The outer metal layer 9 in a and 6c is omitted. Due to the structure of the tapered bearing, the width surface on the small diameter side of the outer ring 3 is
b, and the width surface on the large diameter side becomes the non-load side width surface 6c. The corner between the outer peripheral surface 3a of the outer ring 3 and the width surfaces 3b and 3c on both sides is a chamfered portion. On the non-load-side width surface 3c, the chamfered portion covers the coating layer 6. As shown in the figure, the outer peripheral surface portion 6a
The same three-layer structure as described above may be used.

Each of the metal layers 7, 9 and the insulating layer 8 in the coating layer 6 is a sprayed layer. The surface of the outermost metal layer 9 may be a machined surface. That is,
The metal layer 9 may be sprayed to a thickness including a grinding allowance, and may be subjected to machining such as grinding so that the outer diameter surface or the like has a predetermined size after the spraying. In thermal spraying, a material (powder or rod shape) to be sprayed is melted at an ultra-high temperature and a surface film is formed by colliding with a workpiece by a jet jet. It is desired to set appropriate thermal spraying conditions by using a thermal spray device capable of obtaining a super-high-speed jet and an ultra-high temperature. Each of the metal layers 7, 9 and the insulating layer 8 composed of a thermal spray layer has fine pores,
After the thermal spraying is completed, a sealing process is performed so that moisture does not enter the pores. The sealing treatment is performed with a resin or an adhesive having good permeability, inorganic fine powder, or the like.

As the ceramic material for forming the insulating layer 8, a metal oxide such as alumina (Al ₂ O ₃ ), gray alumina, titanium oxide (TiO ₂ ), chromium oxide (Cr ₂ O ₃ ), or a base material made of these materials And the like. The material of the metal layers 7 and 9 is Al, N
i, Cr, Fe, or the like is used, or a composite material obtained by mixing these materials is used. The metal layers 7 and 9 are preferably made of a relatively soft material having a hardness after spraying of Hv450 or less, preferably Hv300 or less. Further, it is preferable that the metal layers 7 and 9 be non-insulating and have electrical conductivity.

FIG. 2 shows a bearing device in which the anti-corrosion rolling bearing 1 of this embodiment is installed. The two anti-corrosion rolling bearings 1 are arranged inside the housing 10 so that the back faces each other. The back faces of the two bearings, that is, the small-diameter-side width surface 3b of the outer ring 3 is a flange provided on the inner diameter surface of the housing 10. 10a is in contact with the side surface. The outer ring 3 of the dual bearing 1 is fixed to the inner diameter surface of the housing 10 by press fitting. The inner races 2 of the two bearings are fitted to the outer diameter surface of the shaft 11 in a stationary or loosely fitted state. One bearing (right side in the figure) 1
Inner ring 2 is engaged with the step surface 11a of the shaft 11, and the inner ring 2 of both bearings 1 together with the inner ring spacer 12 and the other inner ring spacer 13 interposed therebetween has a female screw member or a retaining ring (not shown). ), It is fixed to the stepped surface 11a in a pressed state.

According to the anti-corrosion rolling bearing 1 of this configuration, since the coating layer 6 has a three-layer structure including the metal layer 7, the ceramic insulating layer 8, and the metal layer 9, the same as in the above proposed example. The following effects can be obtained. That is, since the ceramic insulating layer 8 is interposed between the outer ring 3 and the housing 10, insulation is ensured therebetween, and electrical insulation between the shaft 11 fitted to the inner ring 2 and the housing 10 is improved. Secured. The inner metal layer 7 improves the adhesion of the insulating layer 8 made of ceramics. The outer metal layer 9
When the outer race 3 is tightly fitted to the housing 10, the insulating layer 8 is prevented from peeling off at the time of press fitting.

A feature of the bearing 1 is that the portion 6c of the cover layer 6 covering the non-load-side width surface 3c of the outer race 3 has a smaller number of layers than the portion 6a covering the peripheral surface, that is, FIG. As shown in the figure, since the entire coating layer 6 has a three-layer structure, a part of the thermal spray layer is reduced, so that the thermal spraying process is simplified, the number of processing steps and processing time can be reduced, and the cost can be reduced. Can be achieved. The number of thermal sprayed layers is reduced by the portion 6c covering the non-load-side width surface 3c of the outer ring 3.
In the portion where the number of layers is reduced, since the outermost layer is the insulating layer 8 made of ceramics, there is no problem of insufficient strength of the coating layer 6 when the bearing 1 is used or when the fitting operation is performed. In addition, electrical insulation is ensured. in this way,
The reduction in the function of the coating layer 6 is suppressed, and the cost can be reduced by reducing the number of sprayed layers. As described above, the tapered roller bearing has a large-diameter side surface 3c for cooling during thermal spraying.
However, in the present embodiment, since the number of laminations of the large-diameter-side width surface 3c in the coating layer 6 is reduced as described above, the winding is unlikely to occur.

Next, the test results will be described. Since a part of the sprayed layer was eliminated, a test was conducted to confirm whether there was a crack at the time of a drop impact and a decrease in insulation resistance value. Fig. 3
The outer ring 3 according to the embodiment described with (A) and the outer ring 3 having the three coating layers 6 as a whole shown in FIG. In the test, the test piece was dropped on a steel plate from a position having a height of 100 mm, the presence or absence of cracks in the insulating layer 8 made of ceramics was checked, and the insulation resistance was measured. The portion that first hits the iron plate when each outer ring 3 falls is a chamfer between the outer peripheral surface and the width surface. Table 1 shows the test results.

[0018]

[Table 1]

From the test results shown in Table 1, no cracking at the time of a drop impact and no decrease in insulation resistance were observed, and it was confirmed that it was practicable.

In the above-described embodiment, the covering layer 6 has a basically three-layer structure. However, as shown in FIG.
The portion 6a covering the outer peripheral surface 3a of the outer ring 3 and the portion 6b covering the load side width surface 6b may have a two-layer structure in which the innermost layer is a ceramic insulating layer 8 and the outermost layer is a metal layer 9. In this case, the portion 6c of the coating layer 6B covering the non-load-side width surface 3c of the outer ring 3 has a smaller number of layers by one layer than the portion 6a covering the outer peripheral surface, and may be a single layer of only the ceramic insulating layer 8. Further, in the case of this embodiment, since the sprayed layer directly in contact with the outer ring 3 becomes the ceramic insulating layer 8, the surfaces 3a and 3 of the outer ring 3 where the insulating layer 8 is sprayed are formed.
It is preferable that b and 3c are adhesion-treated surfaces.
The adhesion improving surfaces 3a to 3c are roughened surfaces such as sandblasted surfaces.

As described above, when the coating layer 6 has a two-layer structure, the spraying process is further simplified. In this case, the portion 6c covering the outer ring non-load side width surface 3c of the coating layer 6
Has a single-layer structure composed of a ceramic insulating layer 8, so that the number of processing steps and processing time can be further reduced, and the cost can be reduced. In the case of the tapered roller bearing, when the thermal spray layer of the large-diameter side width surface serving as the outer ring non-load-side width surface 3c is formed as a single layer, the prevention of the bending during cooling during thermal spraying is further ensured. In this embodiment, since the insulating layer 8 made of ceramics is in direct contact with the outer ring 3, the adhesion of the insulating layer 8 is a problem. By devising, it is possible to improve the adhesion of the insulating layer 8 made of ceramics.

FIG. 5 shows still another embodiment of the present invention. This anti-corrosion rolling bearing 1A is formed of a cylindrical roller bearing. More specifically, the inner ring 2A has no flange, the outer ring 3A has both flanges, and the rolling element 5A is a cylindrical roller. The coating layer 6A is provided from the outer peripheral surface 3Aa attached to the housing of the outer ring 3A to the width surfaces 3Ac on both sides. The portion 6Aa of the coating layer 6A that covers the outer peripheral surface 3Aa of the outer ring 3A has a three-layer structure in which the innermost layer is a metal layer 7, the intermediate layer is a ceramic insulating layer 8, and the outermost layer is a metal layer 9. The portion 6Ac that covers the non-load-side width surface 3Ac, which is the width surface on both sides of the outer ring 3A, in the coating layer 6A is smaller in the number of layers by one layer than the portion 6Aa that covers the outer peripheral surface, the inner layer is a metal layer 7, and the outer layer is a ceramic insulating material. Layer 8 is formed.
In the case of a cylindrical bearing without inner ring double flanges, the outer ring 3
The width surfaces 3Ac, 3Ac on both sides of A are non-load-side width surfaces.

As described above, even when applied to a cylindrical roller bearing, the portion covering the non-load-side width surface of the outer ring 3A has a smaller number of laminations than the portion covering the peripheral surface, so that it has excellent electrical insulation and insulation. While obtaining the adhesion of the layer to the raceway or preventing peeling during interference fit, the spraying process is simplified,
Processing man-hours and processing time can be reduced, and costs can be reduced.

[0024]

The anti-corrosion rolling bearing of the present invention is provided with a coating layer extending from the peripheral surface attached to the housing or shaft of the bearing ring to the width surfaces on both sides. The covering portion has a two-layer structure or a three-layer structure in which a ceramic insulating layer and a metal layer are laminated, and the portion covering the non-load-side width surface of the bearing ring in the covering layer has a smaller number of layers than the portion covering the peripheral surface. And, since the outermost layer is an insulating layer made of ceramics, it has excellent electrical insulation properties, while achieving the adhesion of the insulating layer to the raceway, or the anti-separation property at the time of interference fitting, by simplifying the spraying process, Processing man-hours and processing time can be reduced, and costs can be reduced. When the outermost layer of the covering layer covering the outer diameter surface of the bearing ring and the width surface on the load side is a metal layer, peeling of the covering layer at the time of interference fitting of the bearing ring is prevented, and also during use and handling. In this case, damage of the coating layer on the load-side width surface is prevented. When the above-mentioned bearing is a tapered roller bearing, it becomes difficult for the large-diameter width surface to be easily bent during thermal spraying.

[Brief description of the drawings]

FIG. 1 is a partial cross section of an anti-corrosion rolling bearing according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a bearing device using the bearing.

FIG. 3A is a partially enlarged sectional view of an outer ring of the bearing,
(B) is a partial cross-sectional view of an outer ring in a conventional bearing.

FIG. 4 is a partial sectional view of an outer race according to another embodiment of the present invention.

FIG. 5 is a partial sectional view of a bearing according to still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electro-corrosion prevention type rolling bearing 2 ... Inner ring (track ring) 3,3A ... Outer ring (track ring) 3a, 3Aa ... Outer peripheral surface 3b, 3Aa ... Loaded load side width surface 3c, 3Ac ... Load non-load side width surface Moving body 6 ... Coating layer 7 ... Metal layer 8 ... Insulating layer of ceramic 9 ... Metal layer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3J101 AA16 AA25 AA32 AA43 AA54 AA62 BA54 BA56 BA70 EA01 EA41 EA42 FA11 FA44 GA24 5H605 AA12 BB05 CC04 DD01 EB10 EB12 EB16 FF10

Claims (3)

[Claims] 1. A coating layer is provided from a peripheral surface attached to a housing or a shaft of a bearing ring to a width surface on both sides, and a portion of the coating layer covering the peripheral surface of the bearing ring is formed by a ceramic insulating layer and a metal layer. And a three-layer structure in which the number of layers covering the non-load-side width surface of the bearing ring in the coating layer is smaller than the number of layers covering the peripheral surface, and the outermost layer is a ceramic insulating layer. Anti-corrosion-type rolling bearing. 2. The anti-corrosion rolling bearing according to claim 1, wherein the outermost layer of a portion of the coating layer covering the outer diameter surface and the width surface on the load side of the bearing ring is a metal layer. 3. The anti-corrosion rolling bearing according to claim 1, wherein said bearing comprises a tapered roller bearing.