JPH03255223A - Rolling bearing - Google Patents

Abstract

PURPOSE:To improve lubricity and to increase durability by providing a coating layer containing MoS2 on the contacting surface being in contact with respective rolling bodies of a retainer by which a plurality of rolling bodies arranged in the circumferential direction between an outer ring and an inner ring are retained. CONSTITUTION:In a rolling bearing 91, a plurality of steel balls 17 as rolling bodies are arranged between the annular grooves 15, 16 of an outer ring 13 and an inner ring 14, and retainers 18 are provided. The retainer 18 is wholly subjected to nitriding, and a coating layer 20 containing MoS2 being a solid lubricant is provided on the concave spherical contact surface 19 to be in contact with balls 17. The coating layer 20 is formed in such a way that masking is performed except the contact surface 19 of the retainer 18, and particles of MoS2 are dispersed in a thermosetting synthetic resin solution, and then the retainer is immersed in it or the solution is sprayed on the retainer. By the coating layer containing MoS2, lubricity can be improved, and durability can be increased.

Description

Detailed Description of the Invention A1 Object of the Invention (1) Industrial Field of Application The present invention relates to a rolling bearing, in particular an outer ring, an inner ring disposed inside the outer ring, and an interposed device between the outer ring and the inner ring. multiple rolling elements lined up in the circumferential direction and those rolling elements,
The present invention relates to an improvement in a rolling bearing equipped with a cage that holds adjacent bearings with a space between them.

(2) Prior Art Conventionally, the cage of this type of rolling bearing is made of a steel plate, and its contact surface with the rolling elements is a polished surface or a liquid carbonitrided surface.

(3) Problems to be Solved by the Invention For example, when the above-mentioned conventional rolling bearing is used as a rolling bearing for the crankshaft of a two-stroke engine, if the air-fuel mixture containing oil is diluted to prevent emissions, etc., the rolling bearing Since the cooling and lubricating effect of the air-fuel mixture on the air-fuel mixture is reduced, problems arise, particularly in that the durability of the cage and rolling elements is impaired.

In view of the above, an object of the present invention is to provide a rolling bearing that can improve the durability of the cage and the rolling elements.

B0 Structure of the Invention (1) Means for Solving the Problems The present invention provides an outer ring, an inner ring disposed inside the outer ring, and a plurality of rings interposed between the outer ring and the inner ring and arranged in the circumferential direction. In a rolling bearing comprising rolling elements and a cage that holds the rolling elements with a space between adjacent rolling elements, Mo5t is applied to the contact surface of the cage with each rolling element.
It is characterized by providing a coating layer containing.

(2) Effect With the above configuration, even if the external lubrication effect on the rolling bearing decreases, the coating layer containing MoSx exhibits self-lubricating properties, promoting lubrication between the cage and the rolling elements. This makes it possible to improve the durability of the cage and rolling elements.

(3) Example 1. In FIG. 2, a two-cylinder two-stroke engine 2 is mounted on a motorcycle 1, and a main body 3 of the engine 2 is composed of a pair of cylinders 4 and a crankcase 5 that connects both cylinders 4 together.

A piston 7 is slidably fitted into the cylinder pore 6 of each cylinder 4, and a crankshaft 8 is attached to the crankcase 5 at the first. It is rotatably supported via second rolling bearings 93,92. The piston 7 and the crankshaft 8 are connected via a connecting rod 10. In FIG. 2, 11 is a scavenging port.

1st. Second rolling bearing9. ．． 9. The only difference is the size, and the other configurations are the same, so the first rolling bearing 9
．． I will explain about it.

First rolling bearing9. The second. As shown in Figure 3,
An outer ring 13 made of cast iron or the like fitted into the bearing housing 12 of the crankcase 5, an inner ring 14 made of cast iron or the like disposed inside the outer ring 13, and annular grooves 15, 16 of the outer ring 13 and the inner ring 14. A plurality of rolling elements arranged in the circumferential direction, which are interposed between them, are steel poles 17 in the illustrated example, and a steel plate retainer 18 that holds the poles 17 with a space between adjacent ones. We are prepared.

The cage 18 is entirely coated with liquid carbonitriding (LCN).
As shown in FIG. 4, the concave spherical contact surface 19 with each ball 17 is coated with Mo5t, which is solid lubricant fine particles.
A coating layer 20 containing the following is formed.

The method for forming the covering layer 20 is as follows.

(a) Masking other parts of the retainer 18 other than the contact surface 19 thereof.

(b) Prepare a coating liquid in which M o S z fine particles are dispersed in a thermosetting synthetic resin liquid, and add a retainer I8 to the coating liquid.
The coating layer 20 is formed by dipping or spraying a coating liquid onto the contact surface 19.

(C) Curing the coating layer 20. The curing time is about 6 hours when curing at room temperature, about 2 hours when curing at a heating temperature of 150°C, and about 1 hour when curing at a heating temperature of 220°C.

The thickness of the covering layer 20 is 2 to 20 μm, but may be thicker than 20 μm if necessary.

The coating 1i20 formed in this way has a smooth surface, a small coefficient of friction, excellent oil resistance and excellent adhesion to the contact surface 19, and is resistant to washing away even in the presence of oil, grease, etc. Demonstrates good initial stain resistance without staining.

Figure 5 is 1. Second rolling bearing9. ．． 9. and test results when a conventional product is incorporated into the two-stroke engine 2.

The displacement of the engine 2 used was 125 cc, and the engine speed was set to 11.00 rpm.

In order to impose strict conditions on each rolling bearing, the following measures were adopted.

(a) The throttle opening was set narrowly to 15% to reduce the amount of mixture containing oil, thereby worsening the cooling and lubricating effects of the mixture on the rolling bearing.

佽）A twisting force was applied between the outer ring and the inner ring in case an uneven load was generated due to poor assembly.

In FIG. 5, line a is the first line according to the present invention. This applies to the case of the second rolling bearings 93 and 9g, and to the case of the conventional wire thread.

As is clear from line a, the first. Second rolling bearing 91
．． In the case of 9□, the coating layer 20 containing M o S z exhibits self-lubricating properties, so the balls 17 and the retainer 18
This promotes lubrication between the balls 17 and the outer ring 1.
Since the amount of heat conducted to the outer ring 13 is reduced, the temperature rise of the outer ring 13 is suppressed over a predetermined period of time.

The following is inferred from the above results.

When the engine 2 is operated with a twisting force applied between the inner and outer rings 14 and 13, the rolling speeds of the balls 17 will differ due to changes in the rolling positions of the balls 17 between the inner and outer rings 14 and 13. , due to this, the frictional resistance between the ball group 17 and the retainer 18 increases,
The coating layer 20, which is highly self-lubricating, alleviates the frictional resistance.

In the case of the conventional product, as is clear from the lines, the lubricity between the balls and the retainer is reduced, causing the balls to overheat and the temperature of the outer ring to rise sharply in a very short period of time.

In addition, the coating layer 20 may be provided on other parts as well as the contact surface 19, for example, on the entire cage. In this case, the productivity of the rolling bearing can be improved since masking etc. are not required. . The present invention is also applicable to rolling bearings that use rollers as rolling elements.

Effects of C0 invention According to the invention, MoS provided in the cage.

It is possible to provide a rolling bearing that can improve the lubricity between the rolling elements and the cage by the coating layer containing the above, thereby improving the durability of the rolling elements and the cage.

[Brief explanation of drawings]

Figure 1 is a side view of the motorcycle, Figure 2 is a sectional view of the two-stroke engine along the line ■-■ in Figure 1, Figure 3 is a cutaway perspective view of the main parts of the rolling bearing, and Figure 4 is the main part of Figure 3. The enlarged cross-sectional view of FIG. 5 is a graph showing the relationship between engine operating time and outer ring temperature.

Claims (1)

[Claims] An outer ring (13), an inner ring (14) disposed inside the outer ring (13), and the outer ring (13) and inner ring (1
4) A plurality of rolling elements (17
) and a cage (18) that holds the rolling elements (17) with a space between adjacent rolling elements (17), each of the rolling elements (17) of the cage (18)
A coating layer (20) containing MoS_2 is placed on the contact surface (19) with
) A rolling bearing characterized by having: