JP2017129252A - Railroad vehicle bearing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a railroad vehicle bearing unit capable of reducing wearing of a fitting face of an outer ring and a seal plate.SOLUTION: The railroad vehicle bearing unit comprises: an outer ring 21 which is mounted in a housing H of a railroad vehicle; an inner ring 22 which is disposed concentrically with the outer ring 21 and mounted on an axle S of the railroad vehicle; multiple conical rollers 23 that are disposed so as to be freely rolled between the outer ring 21 and the inner ring 22; and an annular seal plate 30 which is fitted and fixed to the outer ring 21 and seals a bearing space. On at least one of a fitting face 31a of the seal plate 30 with the outer ring 21 and a fitting face 21a of the outer ring 21 with the seal plate 30, a molybdenum disulfide coat is formed via a phosphate coat.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a railway vehicle bearing unit that rotatably supports an axle of a railway vehicle.

  As a conventional railway vehicle bearing unit, there is known one in which a sensor is attached to a seal plate fitted to an outer ring which is a fixed ring (see, for example, Patent Documents 1 and 2). Normally, in the railway vehicle bearing units as in Patent Documents 1 and 2, since the housing and the outer ring are fitted with a clearance, the outer ring rotates relative to the housing during operation (creep). At this time, since the seal plate is fitted to the outer ring, there is a possibility that the seal plate and the sensor rotate relative to the outer ring and the sensor cable is disconnected.

  And in order to avoid this problem, in the railway vehicle bearing unit described in Patent Documents 1 and 2, the seal plate is brought into contact with the protrusions or stoppers provided on the seal plate and the ribs provided on the housing. The relative rotation of is suppressed.

Japanese Patent No. 5401848 Japanese Patent No. 5163461

  By the way, in the railway vehicle bearing units described in Patent Documents 1 and 2, when the force (creep force) for rotating the outer ring is relatively large, the outer ring rotates relative to the seal plate. Wear on the mating surfaces of the plates could cause grease leakage. Further, since repeated stress is generated between the protruding portion of the seal plate or the stopper and the rib of the housing, the rib of the housing may be worn or deformed, which may affect the service life of the housing.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a railway vehicle bearing unit that can reduce wear of a fitting surface between an outer ring and a seal plate.

The above object of the present invention can be achieved by the following constitution.
(1) A fixed wheel mounted on the housing of the railway vehicle, a concentric arrangement with the fixed wheel, and a rotatable wheel mounted on the axle of the railway vehicle, and a rotatable wheel disposed between the fixed wheel and the rotating wheel. A rolling stock bearing unit comprising a plurality of rolling elements, and an annular seal plate that is fitted and fixed to a fixed ring and seals a bearing space, the fitting surface of the seal plate with the fixed ring and a fixed ring A railcar bearing unit, characterized in that a molybdenum disulfide coating is formed on at least one of the fitting surfaces with the seal plate via a phosphate coating.
(2) The railway vehicle bearing unit according to (1), further comprising a sensor that is attached to the seal plate and detects a state of the bearing unit.
(3) The seal plate is provided with at least one projecting portion projecting toward the housing, and when the fixed wheel rotates relative to the housing during rotation of the rotating wheel, the projecting portion of the seal plate is formed on the housing. The railcar bearing unit according to (1) or (2), wherein the rotation of the seal plate relative to the housing is prevented by contacting a stop portion provided.

  According to the present invention, since the molybdenum disulfide coating is formed on at least one of the fitting surface of the seal plate with the fixed ring and the fitting surface of the fixed ring with the seal plate via the phosphate coating, By reducing the friction coefficient of the fitting surface between the ring and the seal plate, it is possible to reduce the creep force that tries to rotate the seal plate relatively. For this reason, it is possible to reduce wear of the fitting surface between the fixed ring and the seal plate.

It is the front view which looked at one embodiment of the bearing unit for rail vehicles concerning the present invention from the sensor side. It is the sectional view on the AA line of FIG. It is an expanded sectional view of the periphery of the seal plate of FIG. It is a graph which shows the result of a grease leak confirmation test.

  Hereinafter, an embodiment of a railway vehicle bearing unit according to the present invention will be described in detail with reference to the drawings.

  As shown in FIGS. 1 and 2, the railway vehicle bearing unit 10 according to the present embodiment includes a double-row tapered roller bearing 20 that rotatably supports the axle S of the railway vehicle. And the wheel (not shown) of a railway vehicle is attached to the outer end part (right end part of FIG. 1) of the axle shaft S.

  The double-row tapered roller bearing 20 includes an integral outer ring (fixed ring) 21 fitted in the housing H of the railway vehicle, and a pair of inner rings (concentrically arranged on the inner diameter side of the outer ring 21 and fitted on the axle S). A rotating wheel), a plurality of tapered rollers (rolling elements) 23 that are rotatably arranged between the outer ring 21 and the pair of inner rings 22, and a pair that holds the plurality of tapered rollers 23 at equal intervals in the circumferential direction. And a spacer 25 arranged between the pair of inner rings 22.

  The railcar bearing unit 10 is externally fitted to the axle S and is fitted to the axle S and a cylindrical front lid 26 that comes into contact with the outer end surface of the inner ring 22 on the side away from the wheel. A cylindrical rear lid 27 in contact with the axially outer end surface of the inner ring 22, an annular seal plate 30 that seals between the outer ring 21 and the front lid 26, and the outer ring 21 and the rear lid 27. And a sealing device 40 that seals between the two. In this railway vehicle bearing unit 10, the inner ring 22, the front lid 26, and the rear lid 27 rotate together with the axle S.

  As shown in FIG. 2, the sealing device 40 is attached to the inner peripheral surface of the slinger 41 that is fitted and fixed to the axial outer end of the inner peripheral surface of the outer ring 21, and the outer peripheral surface of the rear lid 27. And a seal member 42 in contact with. Moreover, the labyrinth seal is formed by inserting the front-end | tip part of the slinger 41 into the ditch | groove 27a formed in the back cover 27 via a micro clearance gap.

  As shown in FIG. 3, the seal plate 30 includes an outer diameter side cylindrical portion 31 that is fitted and fixed to an axial outer end portion of the inner peripheral surface of the outer ring 21, and an axial outer end portion of the outer diameter side cylindrical portion 31. An annular portion 32 having a crank-shaped cross section extending inward in the radial direction, and an inner diameter side cylindrical portion 33 extending inward in the axial direction from the radially outer end portion of the annular portion 32. Further, the labyrinth seal is formed by inserting the inner diameter side cylindrical portion 33 of the seal plate 30 into the concave groove 26a formed in the front lid 26 through a minute gap.

  As shown in FIGS. 1 and 2, a sensor 11 that detects the state of the bearing unit 10 is attached to the outer surface in the axial direction of the seal plate 30. In addition, an encoder 12 having an uneven surface formed on the outer peripheral surface of the axle S is fitted in contact with the front lid 26. An annular member 13 including a cover 13a is fixed to the outer end surface in the axial direction of the encoder 12 with a bolt.

  In addition, the seal plate 30 is formed with projecting portions 34 projecting in the housing H direction at a plurality of locations (two locations in the present embodiment) deviated in the circumferential direction from the position where the sensor 11 is attached. The two protrusions 34 come into contact with a stop convex portion (stop portion) H1 provided on the housing H when the outer ring 21 rotates relative to the housing H when the inner ring 22 rotates. The relative rotation of the seal plate 30 is prevented. The stop convex portion H1 is formed so as to protrude radially inward from the inner peripheral surface of the housing H. In addition, although the protrusion part 34 is integrally formed with the sealing plate 30 in this embodiment, you may make it fix to the sealing plate 30 with a screw etc. as another component.

  In this embodiment, as shown in FIG. 3, the seal-side fitting surface 31 a that is the fitting surface with the outer ring 21 of the outer-diameter-side cylindrical portion 31 of the seal plate 30 is provided with a phosphate coating therebetween. A molybdenum sulfide film is formed. Moreover, it is not limited to this, A molybdenum disulfide film may be formed on the outer ring side fitting surface 21a which is a fitting surface with the seal plate 30 on the inner peripheral surface of the outer ring 21 via a phosphate film. . Further, a molybdenum disulfide coating may be formed on both the seal-side fitting surface 31a and the outer ring-side fitting surface 21a via a phosphate coating.

  In addition to the rust prevention effect, the phosphate coating serves as an underlayer for the molybdenum disulfide coating formed thereon, and the molybdenum disulfide coating is firmly bonded to the seal-side fitting surface 31a and the outer ring-side fitting surface 21a. Let

  As a method for forming the phosphate coating, chemical conversion treatment is preferable. The chemical conversion treatment is a general method for forming a phosphate film on the metal surface, and is simple and can reduce the manufacturing cost. Specifically, a phosphate solution containing a phosphate such as iron phosphate, zinc phosphate, or manganese phosphate is applied to the seal-side fitting surface 31a or the outer ring-side fitting surface 21a and heated. To form a coating. Instead of application, the seal-side fitting surface 31a and the outer ring-side fitting surface 21a may be immersed in a phosphate solution.

  Next, as a method of forming a molybdenum disulfide film, a molybdenum disulfide solution containing molybdenum disulfide powder and an appropriate binder is used to form a seal-side fitting surface 31a or an outer ring-side fitting surface on which a phosphate film is formed. It is applied to 21a and the binder is cured to form a film. Instead of application, the seal-side fitting surface 31a and the outer ring-side fitting surface 21a may be immersed in a molybdenum disulfide solution. During film formation, a portion of the molybdenum disulfide powder enters the recesses of the phosphate coating, and the adhesion between the molybdenum disulfide coating and the phosphate coating is enhanced.

  Thus, both coatings can be formed by a simple method such as coating or dipping, and the manufacturing cost can be kept low.

  Further, if both coatings are too thin, the respective effects do not appear or the effects disappear at an early stage. If both coatings are too thick, there is a possibility that the coating will be cracked and peeled off. Therefore, the thickness of the phosphate coating is preferably 2 to 5 μm, and the thickness of the molybdenum disulfide coating is preferably 10 to 20 μm.

  In addition, the additive added to general phosphate films, such as zinc and manganese, can be added to a phosphate film, and these additives are added to a phosphate solution. In addition, other solid lubricants can be added to the molybdenum disulfide coating in order to improve the lubricating performance, and other solid lubricants are added to the molybdenum disulfide solution.

  As described above, according to the railway vehicle bearing unit 10 of the present embodiment, the phosphoric acid is provided on the seal-side fitting surface 31 a that is the fitting surface with the outer ring 21 of the outer-diameter-side cylindrical portion 31 of the seal plate 30. Since the molybdenum disulfide coating is formed via the salt coating, the friction coefficient of the seal-side fitting surface 31a can be reduced, and the creep force that causes the seal plate 30 to rotate relatively can be reduced. For this reason, since the wear of the outer ring side fitting surface 21a and the seal side fitting surface 31a, which are the fitting surfaces of the outer ring 21 and the seal plate 30, can be reduced, grease leakage can be prevented.

  Further, since the creep force that causes the seal plate 30 to rotate relative to each other can be reduced, the stress generated between the protruding portion 34 of the seal plate 30 and the stop convex portion H1 of the housing H can be reduced. Thereby, since the lifetime of the housing H can be extended, the maintenance cost of the bearing unit 10 can be reduced.

In addition, this invention is not limited to what was illustrated to the said embodiment, In the range which does not deviate from the summary of this invention, it can change suitably.
For example, in this embodiment, although the case where this invention is applied to the non-contact seal which forms a labyrinth seal was illustrated, it is not limited to this, You may apply this invention to a contact seal.

  In order to confirm the effect of the present invention, a rolling stock bearing unit (this embodiment) in which a molybdenum disulfide coating is formed on the seal-side fitting surface via a phosphate coating and a rolling stock bearing unit in which no coating is formed (Comparative example) was created, and a grease leakage confirmation test was performed for each. The test time is 1400 hours. The results are shown in FIG.

  As is clear from FIG. 4, about 3.45 g of grease leakage was confirmed in the comparative example, but no grease leakage was confirmed in the example. Therefore, the effectiveness of the present invention in which a molybdenum disulfide film is formed on the fitting surface between the outer ring and the seal plate via the phosphate film has been demonstrated.

DESCRIPTION OF SYMBOLS 10 Railway vehicle bearing unit 11 Sensor 20 Double row tapered roller bearing 21 Outer ring (fixed ring)
21a Outer ring side mating surface 22 Inner ring (rotating ring)
23 Tapered rollers (rolling elements)
30 Seal plate 31 Outer diameter side cylindrical portion 31a Seal side fitting surface 32 Ring portion 33 Inner diameter side cylindrical portion 34 Projection portion H Housing H1 Stop convex portion (stop portion)
S axle

Claims (3)

A fixed wheel mounted on a railway vehicle housing;
A rotating wheel arranged concentrically with the fixed wheel and mounted on the axle of a railway vehicle;
A plurality of rolling elements arranged to be freely rollable between the fixed wheel and the rotating wheel;
An annular seal plate that is fitted and fixed to the fixed ring and seals the bearing space, and a railway vehicle bearing unit,
A molybdenum disulfide coating is formed on at least one of a fitting surface of the sealing plate with the fixed ring and a fitting surface of the fixed ring with the sealing plate via a phosphate coating. Bearing unit for railway vehicles.   The railway vehicle bearing unit according to claim 1, further comprising a sensor attached to the seal plate and detecting a state of the bearing unit. The seal plate is provided with at least one protrusion that protrudes toward the housing,
When the fixed wheel rotates relative to the housing during rotation of the rotating wheel, the protruding portion of the seal plate contacts a stop provided on the housing, so that the seal plate with respect to the housing Relative rotation is prevented, The railway vehicle bearing unit according to claim 1 or 2 characterized by things.

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