JPH0617072A - Sliding member - Google Patents

Abstract

PURPOSE:To provide a sliding member which is excellent in abrasion resistance. durability, and dry characteristics and used as an end-sealing member of a mechanical seal, a supporting member such as a bearing which supports a rotating or sliding member, a sleeve fitted to a rotating or sliding shaft, etc. CONSTITUTION:A sliding member is made of a composite material obtd. by dispersing boron nitride in tungsten carbide. Boron nitride dispersed eliminates defects, such as inferior dry characteristics or low resistance to thermal shock, of tungsten carbide while maintaining the excellent characteristics, such as high resistances to abrason and corrosion, inherent in the latter. Thus, the sliding member exhibits very good sliding functions even in a dry atmosphere, such as in a gas or vapor, or under completely nonlubricated conditions without using any lubricating means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supporting member such as a sealed end surface member for mechanically sealing a sealed fluid by a relative rotary sliding contact action, a sliding bearing member for supporting a rotating member or a sliding member. The present invention relates to a sliding member which is fitted to a rotary shaft or a slide shaft and is preferably used as a sleeve for preventing wear and adjusting the diameter of the rotary shaft or the slide shaft.

[0002]

2. Description of the Related Art For example, a sealed end face member of a mechanical seal is generally made of a hard material such as tungsten carbide or ceramics or a soft material such as carbon. However, with mechanical seals,
When one of the two sealing end face members that make relative rotational sliding contact is made of a soft material such as carbon, a large amount of abrasion powder is generated due to the sliding contact with the mating sealing end face member. Therefore, the mechanical seal using the sealing end member made of such a soft material may contaminate the sealed fluid with abrasion powder,
It cannot be used at all for equipment that requires cleaning of sealed fluid (for example, medical equipment, pharmaceutical / food manufacturing equipment, bio-related equipment, powder transportation equipment, etc.). On the other hand, when both of the two sealing end face members are made of a hard material such as tungsten carbide, such hard material has abrasion resistance, chemical resistance,
Although it has excellent sliding material characteristics such as heat resistance, it has poor so-called dry characteristics, unlike carbon, etc., so in a dry atmosphere such as gas or steam, unless some lubricating means is provided. There is a risk that seizure may occur at the sliding contact portion with the mating sealed end face member, or thermal cracks or abnormal wear may occur. Further, when the lubricating means is provided, the sealed fluid may be contaminated by the lubricating material, so that it cannot be used in the above-mentioned medical equipment or the like.

In the bearing portion of deep well pumps, mixed flow pumps, axial flow pumps, canned pumps, etc., carbon rubber, white metal, kelmet, etc. are generally used as bearing members for supporting rotary shafts such as pump shafts. A bearing made of a soft material is used, but such a bearing member is poor in wear resistance and has a problem in durability. Therefore, when the pumping liquid is poor in slurry resistance and contains a solid substance such as slurry water, it cannot be used well. Of course, when the bearing member is made of the above-mentioned hard material such as tungsten carbide or ceramics, sliding contact with the mating shaft member causes the same problem as described above. These problems are similarly pointed out also in a supporting member other than the above-mentioned bearing member for supporting the rotating member or the sliding member, and in a sleeve for fitting the rotating shaft or the sliding shaft to adjust the diameter thereof. There is.

As described above, the conventional sliding member has a problem in slidability and durability under a dry atmosphere or under non-lubricated conditions, and its use is substantially limited.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide various sliding members which are rich in wear resistance and durability and which are excellent in dry characteristics. Is.

[0006]

Each of the sliding members of the present invention, which has solved this problem, is particularly composed of a composite material in which boron carbide is dispersed and blended with boron nitride.

Specifically, this sliding member is obtained, for example, by adding an appropriate amount of boron nitride powder to tungsten carbide powder, mixing them, press-molding the mixture into a predetermined shape, and then sintering. To be The addition amount of boron nitride is preferably 5 to 20% by volume.

Since boron nitride is a self-lubricating substance as is well known, the dry characteristics of tungsten carbide in which it is uniformly dispersed and mixed are greatly improved as compared with ordinary tungsten carbide.

Moreover, since boron nitride has excellent wear resistance, corrosion resistance and the like like tungsten carbide, the characteristics of tungsten carbide itself are not impaired by blending boron nitride. That is, it is possible to eliminate the defect that the dry characteristics are inferior while maintaining the characteristics of the tungsten carbide as the sliding member as it is.

Further, since boron nitride is dispersed in the structure of tungsten carbide, thermal cracks are prevented in the dispersed pores, so that the heat crack resistance is significantly improved. Stress is relieved in the dispersed boron nitride portion, toughness is improved, and thermal shock resistance is improved.

Furthermore, since boron nitride, that is, a solid lubricant is dispersed and mixed in tungsten carbide, the lubricant flows out and deteriorates the characteristics of the sliding material itself as in the case of using an oil-containing material. There is no such thing.

[0012]

As is apparent from the above description, according to the present invention, the characteristics such as the wear resistance and the corrosion resistance originally possessed by tungsten carbide are secured as they are, and the dry characteristics can be obtained by blending boron nitride. Sliding member that can eliminate defects such as heat resistance and thermal shock resistance, and can exhibit extremely good sliding function even in a dry atmosphere such as gas or steam, or even under completely unlubricated conditions without using any lubricating means. Can be provided.

Therefore, by using the sealing end face member, the supporting member or the sleeve which is the sliding member of the present invention,
The functions and durability of various devices such as mechanical seals and bearings can be greatly improved, and the applications of such devices can be greatly expanded. For example, when the sliding member of the present invention is used as both sealing end face members in a mechanical seal, a good dry operation can be performed without generating wear powder, and medical equipment that is reluctant to contaminate a sealed fluid,
A good sealing function can be exhibited even in manufacturing equipment for pharmaceuticals and foods. Of course, even when the generation of abrasion powder is allowed or the dry operation is not required, by using the sliding member of the present invention for at least one of the sealing end face members, the sealing function and durability of the mechanical seal can be improved. Sex can be greatly improved. Further, when the sliding member of the present invention is used as a bearing member for a pump shaft, a good bearing function and therefore a pump function can be exerted for a long period of time regardless of whether or not the pumping liquid has a slurry property. Furthermore, when the sliding member of the present invention is used as a sleeve fitted to a rotating shaft or a sliding shaft, the function, durability, etc. of the equipment used can be greatly improved.

As described above, the sliding member of the present invention almost completely eliminates the disadvantages of the sliding function of various conventional sliding members, and can be used in a wide variety of applications. It is of great value.

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Claims (3)

[Claims] 1. A sliding member, which is a hermetically sealed end face member in a mechanical seal, and is made of a composite material in which boron nitride is dispersed and blended in tungsten carbide. 2. A sliding member material, which is a supporting member for supporting a rotating member or a sliding member, and is made of a composite material in which boron nitride is dispersed and blended in tungsten carbide. 3. A sliding member fitted to a rotary shaft or a slide shaft, comprising a composite material made of tungsten carbide in which boron nitride is dispersed and blended.