JPH08121617A - Ceramics sliding material and sliding device using the same - Google Patents

Abstract

PURPOSE: To provide a ceramics sliding member capable of being used for a long time as a sliding member which is light in the operating force and small in the friction and safe by forming a part of the sliding surface of the porous ceramics body, and impregnating the open pores with at least one kind of lubricant to be selected from the vegetable oil or mineral oil. CONSTITUTION: The sliding surface is formed of the porous ceramics body 1, and this porous ceramics body 1 is provided with the pores 2 uniformly on the sliding surface 3 and on the inner surface, and the pores 2 of at least the sliding surface 3 is impregnated with the lubricant of the vegetable oil or the mineral oil. Thus, the sliding surface 3 is formed of the hard and porous ceramics body 1 and the lubricant 4 to demonstrate the excellent wear resistance and the slidability. The lubricant of the vegetable oil is basically made of the fatty acid glycerite to be obtained by refining the food stearin contained in the natural vegetable oil or the edible oil. The lubricant of the mineral oil consists of the liquid saturated hydrocarbon to be selected from paraffin, naphthen and aromatics.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding member such as a valve, a mechanical seal or a slider, and more particularly to a sliding member having a porous ceramic body impregnated with a lubricant.

[0002]

2. Description of the Related Art By moving a movable valve body relative to a fixed valve body housed in a valve body in a state of sliding contact by operating an operating lever, it is possible to open, close, switch, adjust, mix, etc. fluid passages. Many valves that have been designed to be controlled have already been proposed.

For example, as shown in FIG. 4 (A), the fixed valve body 30 and the movable valve body 20 are in contact with each other at their sliding contact surfaces 21 and 31, and as shown in FIG. 4 (B). By moving the movable valve body 20 by operating the lever 40, the fluid passages 22 and 32 formed in the valve bodies are opened and closed,
There is a valve that controls the opening / closing and adjustment of the supply fluid.

And, there is the following demand for such a forset valve.

The fixed valve body 30 and the movable valve body 20 do not adhere to each other, and the operation lever can always be operated lightly, and the force required for the operation does not change.

No unpleasant noise is generated during operation.

As a matter of course, there should be no contamination of water or outflow of wear powder of valve material.

By the way, since ceramics generally have excellent wear resistance and corrosion resistance, they are used as the movable valve body 20 and the fixed valve body 30 of the above-mentioned Faucet valve. On the other hand, ceramics are self-lubricating. Is often inferior to.

Therefore, in order to improve the lubricity and to obtain the light lever operating force as described above, the sliding contact surfaces 21, 3 are
Generally, a method of using silicone grease applied to No. 1 is used. However, if grease is simply applied to the sliding surfaces 21 and 31 of the dense ceramics, the grease is leaked after being used several thousand times, and the operating force is increased accordingly. It had poor durability such as adhesion.

Therefore, as a means for improving such problems, Japanese Patent Publication No. 58-161982 discloses "Ceramics composite in which fluoropolymer is bonded to ceramics".
The invention relating to “Japanese Patent Publication No. 2-51864” discloses an invention relating to “β-type SiC quality sliding member” in Japanese Examined Patent Publication No. 2-28.
No. 548, “Slid member made of SiC having a three-dimensional mesh structure”
The invention relating to JP-B-3-1274 discloses an invention relating to "a sliding member obtained by impregnating a mesh structure SiC with spindle oil", and an invention relating to JP-A-3-4511 discloses a synthetic resin for SiC that does not substantially shrink. The invention relating to the "sliding member impregnated with" is disclosed in Japanese Patent Publication No. 4-69118, and the invention relating to "a sliding member obtained by impregnating a ceramic porous body having a three-dimensional network structure with fluorine oil" is disclosed in Japanese Examined Patent Publication No. 5-18790. Japanese Patent Publication No. 4-56 discloses an invention relating to "a sliding member obtained by filling a synthetic resin in a porous oxide ceramic having a three-dimensional mesh structure".
The inventions relating to "a sliding member obtained by impregnating a ceramic porous body having a three-dimensional mesh structure with a fluorine-based / silicone-based resin" are disclosed in Japanese Patent No. 908, respectively, and a lubricant such as a resin is provided in the pores of the porous ceramic body. Impregnated sliding members have been proposed.

In addition to the above-mentioned liquid lubricant, solid lubricant is also used.
-261570 discloses an invention relating to "a mechanical seal having a diamond-like carbon thin film formed on a sliding surface", and JP-B-3-223190 discloses an invention relating to "a ceramic sliding structure having an amorphous diamond thin film". Are disclosed respectively.

[0012]

The grease used for sliding between the dense ceramic bodies is engine oil, spindle oil, dynamo oil, turbine oil, etc., and a lubricant for impregnating the pores of the porous ceramic body. Were fluorine-based oils, silicone oils, synthetic resins and the like. However, these are synthetic oil type lubricants, which are not only expensive but also belong to dangerous substances such as the 4th and 3rd petroleums defined by the Fire Service Law because they are oils obtained by refining petroleum. Moreover, there is a problem that some of them have harmful effects such as acute toxicity, carcinogenicity and mutagenicity. In particular, it was not a preferable lubricant for use in a valve body for a faucet such as a faucet valve which may always enter the human body.

On the other hand, the surface of a dense ceramic body coated with a so-called synthetic pseudo diamond (DLC) such as a diamond-like carbon thin film or an amorphous hard carbon film has a remarkable improvement in slidability. Although a light operating force was obtained, an unpleasant noise was sometimes generated during sliding, and the sliding member was not yet perfect.

[0014]

In view of the above problems, the present invention relates to a ceramic sliding member having at least a part of a sliding surface made of a porous ceramic body, in which open pores of the porous ceramic body are provided. Further, it is impregnated with at least one lubricant selected from mineral oils or vegetable oils which does not contain components harmful to the human body such as heavy metals.

By combining a sliding member impregnated with these lubricants and a sliding member having a synthetic pseudo diamond thin film on the sliding surface, the sliding characteristics are maximized and a smooth operating force is obtained. It is intended to provide a comfortable operating environment without generating abnormal noise.

[0016]

The sliding member of the present invention comprises a porous ceramic body having high wear resistance and corrosion resistance, which is impregnated with a highly safe lubricant of mineral oil type or vegetable oil type. The present invention provides a safe sliding member at a low cost, which is extremely less affected by the contamination of ceramics and the toxicity of oil.

Regarding the sliding characteristic, it is possible to obtain a smooth operating force for a long period of time without producing abnormal noise due to the lubricity of oil.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the ceramic sliding member of the present invention comprises a porous ceramic body 1. The porous ceramic body 1 is provided with pores 2 evenly on the sliding surface 3 and the inner surface, and at least slides. The pores 2 of the moving surface 3 are impregnated with a vegetable oil-based or mineral oil-based lubricant 4. Therefore, as shown in FIG. 2, the sliding surface 3 is formed of the highly porous ceramic body 1 and the lubricant 4, and can exhibit excellent wear resistance and slidability.

Further, in FIG. 1, the entire sliding member is formed of the porous ceramic body 1, but only the portion in the vicinity of the sliding surface 3 is formed of the porous ceramic body 1 and joined to other members. good. Alternatively, only a part of the sliding surface 3 can be formed by the porous ceramic body 1.

Here, an example in which the sliding member of the present invention is applied to a facet valve will be shown. As shown in FIG. 3, both or one of the two valve bodies 10 and 10 having the fluid passages 12 are formed of the porous ceramic body 1 forming the sliding member of the present invention, and the sliding surface 3 is the valve body 10. The sliding contact surface 11 is formed.

In this facet valve, since the valve body 10 is excellent in slidability, there is no abnormal noise, a necessary and sufficient operating force can be obtained, and a highly safe lubricant 4 is used. Even if the lubricant 4 flows out into the fluid flowing through the fluid passage 12, it does not adversely affect the human body.

In the sliding member of the present invention, it is preferable that the pores 2 of the porous ceramic body 1 communicate with each other in order to impregnate a large amount of the lubricant 4. The porous ceramic body 1 has an open porosity of 3 to 50% as a whole.
Is desirable. The reason for this is that if the open porosity is less than 3%, the substantial amount of the lubricant 4 to be added will be small and the effect of reducing the operating force will be poor.
This is because the wear resistance of the porous ceramic body 1 itself becomes low when the content is at least%.

The pores 2 of the porous ceramic body 1 preferably have an average pore diameter of 10 μm or less. The reason for this is that if the average pore diameter is 10 μm or less,
This is because the outflow of the lubricant 4 is moderately balanced and the amount suitable for lubrication exudes for a long period of time. Further, when used as a facet valve as shown in FIG. 3, the porous ceramic body 1 itself which constitutes the valve body 10 needs to have a sealing property, but if the average pore diameter is made extremely small to 10 μm or less,
The fluid can be prevented from leaking.

The portion of the sliding surface 3 of the porous ceramic body 1 excluding the pores 2 is preferably an extremely flat surface having a flatness of 3 μm or less, preferably 1 μm or less.
This is to prevent fluid from leaking from the sliding contact surface 11 when used as a facet valve.

As the above-mentioned porous ceramic body 1, a material having high wear resistance and chipping resistance, that is, high hardness and toughness must be used in order to prevent foreign matter from entering the human body and enhance safety. Is most preferably ceramics containing alumina, zirconia, silicon carbide, silicon nitride, aluminum nitride, cordierite or the like as a main component.

For these raw materials, alumina is SiO ₂ , MgO, etc., silicon nitride is Y ₂ O ₃ for oxides, nitrides and zirconia of Periodic Table 2a and 3a elements. If an auxiliary agent such as CaO, CaO, MgO or CeO ₂ is added and fired, it is possible to obtain a ceramic body which is strong, robust and excellent in toughness and wear resistance due to shrinkage of substantially 3% or more. .

At this time, if a resin and a foaming agent are added to and mixed with these ceramic raw materials to form a predetermined shape and then the mixture is fired, the added resin and the foaming agent are burnt off during firing and the pores 2 are formed.
It is possible to easily obtain the porous ceramic body 1 having Here, it is also possible to freely adjust the open porosity and the pore diameter by changing the addition amount of these resins and the foaming agent, the particle diameter and the like.

Further, it is not always necessary to mix the resin and the foaming agent, and the porosity 2 can be obtained by adjusting the firing conditions using a normal ceramic raw material so as not to completely sinter.
Can also be formed.

Finally, the sliding surface 3 of the obtained sintered body is polished to a flatness of 3 μm or less, preferably 1 μm or less, and then the lubricant 4 is impregnated. As a method of impregnation, an impregnation method such as immersing the porous ceramic body 1 in the lubricant 4 whose viscosity has been reduced by heating and then impregnating it under vacuum or pressure may be used.

Here, it is important to use a mineral oil-based or vegetable oil-based lubricant 4 as the lubricant 4 with which the porous ceramic body 1 is impregnated. The reason is that by impregnating the porous ceramic body 1 having excellent wear and toughness with the vegetable oil-based or mineral oil-based lubricant 4 having excellent lubricating characteristics and safety, sliding characteristics can be improved without impairing safety. This is because it can be remarkably improved.

The vegetable oil-based lubricant is an oil obtained by refining a natural vegetable oil, and more specifically, a food sterin contained in the natural vegetable oil or a fatty acid glycerite obtained by refining the food oil. A base oil is used.

The mineral oil-based lubricant is a mixture containing hydrocarbon as a main component, which is obtained by refining petroleum by a physical operation, and is specifically selected from paraffin, naphthene and aromatic. An oil mainly composed of liquid saturated hydrocarbon is used.

Any one or more of these vegetable oil-based or mineral oil-based lubricants may be used in combination, and all of them may be in various states such as liquid, grease and wax. It can be used.

Since these vegetable oil-based or mineral oil-based lubricants do not contain impurities such as heavy metals and sulfur, they are not only safe as they pass the Food Sanitation Law and Pharmaceutical Affairs Law, but also
It also has excellent lubricity and durability.

In addition to the above vegetable oil-based or mineral oil-based lubricants, generally used lubricants are synthetic oil-based lubricants, which are chemicals using petroleum gasified to olefin as a raw material. It is obtained by synthetic synthesis and consists of a single substance or a homologous mixture. Specifically, there are hydrocarbon type, ether type, ester type, silicone type, fluorine type and the like, and they are used as engine oil, spindle oil and the like.

In the sliding member of the present invention, it is preferable to impregnate 100% by volume of the porous ceramic body 1 with at least 3% by volume or more of the vegetable oil-based or mineral oil-based lubricant 4. The reason is that it is difficult to improve the sliding characteristics when the impregnation amount of the vegetable oil-based or mineral oil-based lubricant 4 is less than 3% by volume.

Further, one valve body 10 forming the facet valve shown in FIG. 3 is formed by the sliding member of the present invention,
The other valve body 10 is made of dense ceramics, and a synthetic pseudo diamond thin film (also known as amorphous hard carbon film / diamond-like carbon / DLC) obtained on the sliding contact surface 11 by vapor deposition means such as PVD or CVD. -I-carbon) can also be coated.

By doing so, the sliding property is further improved,
It is possible to eliminate the generation of abnormal noise, which was difficult to solve only with synthetic pseudo diamond. This is because the properties of synthetic pseudo diamond have an extremely good affinity with the lubricating oil, and due to the synergistic effect of the solid lubricant and the liquid lubricant,
This is because the slidability can be remarkably improved.

Further, in the above embodiment, an example in which the flat surfaces are slid with each other is shown, but the sliding member of the present invention may be applied to the sliding surface having a cylindrical shape or a spherical shape. it can. Therefore, the ceramic sliding member of the present invention can be used for various applications such as ball valves and sliders, various bearings and mechanical seals, as well as the Faucet valve.

Experimental Example 1 A porous ceramic body 1 made of alumina, zirconia, silicon nitride, silicon carbide and cordierite having various porosities and pore sizes as shown in Table 1 was prepared. The porous ceramic body 1 is impregnated with a vegetable oil-based or mineral oil-based lubricant 4 as an example of the present invention, and a synthetic lubricating oil-based lubricant 4 as a comparative example, and slidability, foreign matter outflow, and water pollution An experiment was conducted to investigate such things.

The porosity was measured by the Archimedes method, and the pore diameter was measured based on an enlarged SEM photograph of the sliding surface, which is the average value of the maximum diameters of the respective pores.

[0043]

[Table 1]

First, as shown in FIG. 3, while holding the valve body 10 consisting of a pair of sliding members from above and below with a load of 30 kg, the valve body 10 was set on the water tap as shown in FIG. Only the movable valve body was rotated, and the relationship between the initial value of the operating force and the porosity of the sliding member was examined.

As a result, the results shown in FIG. 5 were obtained regardless of the ceramic material and the type of the lubricant 4. That is, regardless of the type of the lubricant 4, the lower the porosity, the higher the initial value of the operating force, and when the porosity was 2.5% by volume, adhesion (linking) occurred. On the other hand, the porosity is 3
If it is more than volume%, it will be a usable level, especially 5
At volume% or more, the operating force was particularly excellent at 0.6 Kg or less.

Here, since the lubricant 4 has entered the pores 2, the porosity and the oil content are almost equal. In other words, the amount of the lubricant contained is 3% by volume or more, preferably 5% with respect to 100% by volume of the ceramic body.
It was found that the volume% or more is required.

Experimental Example 2 Next, a vegetable oil-based lubricant containing a fatty acid glycerite as a base oil, which was obtained by purifying a natural vegetable oil, was used, which had a porosity of 10% by volume and an average pore diameter of 1 μm. A mineral oil-based lubricant that uses liquid paraffin refined by hydrorefining as a base oil, and a synthetic lubricating oil-based lubricant that uses phosphate ester as a base oil are impregnated respectively, and the sliding is performed in the same manner as above. The water quality that came out through the valve was checked by rotating it dynamically. As a result, in the case of using the vegetable oil-based lubricant and the mineral oil-based lubricant according to the examples of the present invention, the water quality was not polluted and no impurities were detected in the water. However, in the case of using the synthetic lubricant oil diameter lubricant which is a comparative example, the water quality contains impurities such as phosphorus, sulfur and heavy metals, which adversely affect the human body, and is not suitable as a valve component for waterworks. I understood.

Experimental Example 3 Next, alumina, zirconia, silicon nitride, aluminum nitride, silicon carbide and cordierite having a porosity of 10% by volume and an average pore diameter of 1 μm were impregnated with a vegetable oil type lubricant,
In the same manner as described above, the surface change (wear amount and grain shedding) of the sliding member after sliding 100,000 times was examined.

As a result, regarding the ceramic made of alumina, zirconia, silicon nitride and aluminum nitride,
Whereas wear, chipping and shedding were not detected,
In silicon carbide and cordierite, wear of about 1 μm on average was confirmed, and shedding of about 0.1 to 10 μm in diameter was found,
It turned out that it is not very preferable as a valve. On the other hand, with respect to the operating force of any test piece after the first to 100,000 times,
From the fact that the operating force of 0.6 kg or less, which is the numerical reference of the smooth operating force, was maintained and no abnormal noise was generated, it was found that there was no problem with the lubricating performance.

Experimental Example 4 In addition, one using the sliding member of the above-mentioned embodiment of the present invention, one in which a synthetic pseudo diamond thin film was further formed on one sliding member, and dense alumina ceramics were greased together as a comparative example. The relationship between the number of times of operation and the operation torque was examined for three types that were slid through.

The results are shown in FIG. In the comparative example coated with grease, adhesion (linking) occurred after about 100,000 times of use, and it became unusable, whereas in the example of the present invention, it can be used satisfactorily even for 1 million times or more. .

From these results, in the sliding member having at least a part of the sliding surface made of porous alumina ceramics, zirconia ceramics, silicon nitride ceramics, and aluminum nitride ceramics, in the open pores of the porous ceramic body. If you impregnate at least one lubricant of vegetable oil type or mineral oil type, the operating force is light,
In addition, the amount of wear is small, and a safe sliding member can be used for a long period of time.

By the way, the other ceramic valve body, which is combined with the sliding member according to the present invention, coated with the synthetic pseudo diamond thin film, as shown in FIG. It turned out that there was no occurrence. It should be noted that, in the case where only the synthetic pseudo diamond thin film was coated, an unpleasant noise such as a squealing noise was sometimes generated during sliding, but it can be solved by combining with the sliding member of the present invention. confirmed.

Experimental Example 5 Next, in order to investigate the relationship between the average pore diameter and the number of times of sliding, alumina, zirconia, which had a porosity of 10% by volume,
Each of the silicon nitride and aluminum nitride porous ceramic bodies was impregnated with a vegetable oil-based lubricant, and a sliding test was conducted in the same manner as above. In this test, when the number of operations while maintaining an operating force of 0.6 kg or less was checked, the results shown in FIG. 7 were obtained regardless of the ceramic material.

As shown in FIG. 7, the average pore diameter is 50 μm.
It was found that when the average pore diameter is 20 μm or less, sufficient durability of 100,000 times or more can be obtained, though the durability is slightly difficult when the average pore diameter is 20 m or more. It is considered that this is because the lubricant impregnated into the pores easily flows out as the pore diameter increases.

If the average pore diameter is 10 μm or less, preferably 1 μm or less, the outflow of the lubricant is suppressed appropriately, and good slidability can be obtained for a long period of time.

Experimental Example 6 Next, in order to investigate the relationship between the porosity and the wear amount, a vegetable oil type lubricant was added to each porous ceramic body of alumina, zirconia, silicon nitride and aluminum nitride having an average pore diameter of 1 μm. Impregnation was performed, and a sliding test was performed in the same manner as above.
In this test, when the amount of wear after 100,000 cycles was checked, the results shown in FIG. 8 were obtained regardless of the ceramic material.

As shown in FIG. 8, it is understood that the wear amount can be reduced by setting the porosity to 50% by volume or less.
Further, considering that the oil content is preferably 3% by volume or more as described above, the porosity is preferably 3 to 50% by volume.

[0059]

As described above, according to the present invention, in a sliding member in which at least a part of the sliding surface is made of a porous ceramic body, a vegetable oil type or a mineral is provided in the open pores of the porous ceramic body. By impregnating with at least one lubricant selected from the oil system, it is possible to use a sliding member that has a light operating force, a small amount of wear, and is safe, for a long period of time. Therefore, it can be suitably used as various valves, seal rings, slider parts, various bearings, and the like.

The mating member that slides with the sliding member of the present invention is made of dense ceramics and is coated with a synthetic pseudo diamond thin film to further improve slidability and prevent abnormal noise. You can also do it.

[Brief description of drawings]

FIG. 1 is a perspective view of a ceramic sliding member according to the present invention.

FIG. 2 is an enlarged surface photograph of a ceramic sliding member according to the present invention.

FIG. 3 is a schematic view of a facet valve using the ceramic sliding member of the present invention.

FIG. 4 is a schematic view of a general faucet valve incorporated in a water tap.

FIG. 5 is a graph showing the relationship between the porosity and the initial value of the operating force in the ceramic sliding member of the present invention.

FIG. 6 is a graph showing the relationship between the number of times of sliding and the operating force in the present invention and the comparative example.

FIG. 7 is a graph showing the relationship between the average pore diameter and the operating force in the ceramic sliding member of the present invention.

FIG. 8 is a graph showing the relationship between the porosity and the wear amount in the ceramic sliding member of the present invention.

[Explanation of symbols]

 1: Porous ceramic body 2: Porosity 3: Sliding surface 4: Lubricant 10: Valve body 11: Sliding surface 12: Fluid passage

Claims (4)

[Claims] 1. At least a part of a sliding surface is made of a porous ceramic body, and the open pores of the ceramic body are impregnated with at least one lubricant selected from vegetable oils or mineral oils. Characteristic ceramic sliding member. 2. The ceramic sliding member according to claim 1, wherein the vegetable oil-based lubricant uses a food sterin contained in natural vegetable oil or a fatty acid glycerite obtained by refining the food oil as a base oil. . 3. The ceramic sliding member according to claim 1, wherein the mineral oil-based lubricant comprises a liquid saturated hydrocarbon selected from paraffin, naphthene, and aromatic. 4. A sliding device in which the ceramic sliding member according to claim 1 and a sliding member made of a dense ceramic body are combined, and a synthetic pseudo diamond thin film is coated on the sliding surface of the dense ceramic body. A sliding device characterized by being worn.