JPH07260014A - Disc valve - Google Patents

Abstract

PURPOSE:To prevent abrasion of valve bodies and generation of linking by forming one of valve bodies mutually sliding by/metal or ceramics, and uniformly dispersing carbon to an aggregate made of silicon carbide and silicon nitride within the specific weight % range, so as to make the other valve containing it. CONSTITUTION:One side valve body for constituting a disc valve 10 is made of metal or ceramics. Moreover, carbon as a self-lubricating material is uniformly dispersed to an aggregate made of silicon carbide and silicon nitride within the range of 2 to 30wt.%, so as to be contained in the other valve. And, a movable valve body 20 is moved in a state where a fixed valve body 30 and the movable valve body 20 are brought in contact with each other at their slide-contact surfaces 21, 31, thereby fluid passages 22, 32 provided on respective valve bodies 20, 30 are opened and closed, so as to perform adjustment of a flow rate of supplying fluid. Since carbon as a self-lubricating material exists within the specific range on one side of the slide-contact surface in this disc valve, the coefficient of friction between the valve bodies can be extremely decreased, thereby any linking is not generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk valve composed of a movable valve body and a fixed valve body used in the construction of a water faucet, a hot and cold water mixing faucet, a medical sampling valve, a chemical liquid valve and the like.

[0002]

2. Description of the Related Art A disk valve used for a faucet, a hot and cold water mixing valve, a medical sampling valve, and a chemical liquid valve has two disc-shaped valve bodies slidably contacting each other to be slid relative to each other. The fluid passage formed in the body is opened and closed. For example, the faucet valve used as a faucet or a hot and cold water mixing tap is shown in FIG.
As shown in (A), the solid valve body 30 and the movable valve body 20.
With the sliding contact surfaces 21 and 31 in contact with each other,
As shown in FIG. 6B, the movable valve body 2 is operated by operating the lever 40.
By moving 0, the fluid passages 22 and 32 formed in the valve bodies 20 and 30 are opened and closed, and the flow rate of the supply fluid is adjusted.

The movable valve body 20 and the fixed valve body 3 are provided.
In the case of 0, high dimensional accuracy is required to maintain slidability and sealability, wear is severe due to continuous sliding, and corrosion is severe due to constant exposure to fluid. It can be processed with high precision and is made of ceramics with excellent wear resistance and corrosion resistance.

By the way, the slidability and the sealability are contradictory. In order to improve the sealability, the sliding contact surface is made extremely smooth, and a pair of valve bodies having these sliding contact surfaces are slid together. Then, there was a catch and an abnormal noise, and further, linking (adhesion) of the valve bodies sticking to each other and not moving. It has also been known that the sliding torque gradually increases as the number of sliding times increases even if linking is not achieved.

Therefore, various solutions have been proposed to prevent linking.

For example, there is one in which the valve body is made of porous ceramics having a three-dimensional mesh structure, and the open pores are impregnated with resin or oil as a lubricant (Japanese Patent Laid-Open No. 61-206).
875, 61-244980, 62-4949,
62-37517, Japanese Patent Publication No. 5-50475).

Further, there is one in which carbon having a lubricating action is vapor-deposited or silicon carbide is coated on the sliding contact surface of the ceramic valve body.

[0008]

However, in the porous ceramics having a three-dimensional network structure in which the open pores are impregnated with resin or the like, the bonding force between the resin portion and the ceramic portion is weak, and the resin is accompanied by sliding. There was part missing. Therefore, the lubrication effect cannot be obtained by the resin part, the friction coefficient increases, and the sliding contact surface becomes uneven so that abnormal wear occurs and the ceramic part comes off. There is a problem in that the slidability and the sealability are significantly reduced such that the surface cannot be evenly worn. Moreover, the manufacture of such a valve body is not easy and expensive.

On the other hand, when the sliding contact surface is vapor-deposited with carbon or coated with silicon carbide, smooth sliding characteristics can be obtained temporarily, but the carbon or silicon carbide film wears out after long-term use. However, there is a drawback that the occurrence of linking is unavoidable. Moreover, the coefficient of thermal expansion does not match depending on the substrate on which the carbon film or the silicon carbide film is formed, and the film may peel off when hot water flows.

It is an object of the present invention to provide a disc valve in which both valve bodies are less likely to wear and have smooth slidability without causing linking for a long period of time.

[0011]

In view of the above-mentioned problems, one of the valve bodies constituting the disk valve is made of metal or ceramics, and the other valve body is made of silicon carbide and silicon nitride. The material is composed of a composite ceramic in which carbon, which is a self-lubricating substance, is uniformly dispersed and contained in the range of 2 to 30% by weight.

[0012]

In the disk valve according to the present invention, carbon, which is a self-lubricating substance, exists in one sliding contact surface within a predetermined range, so that the friction coefficient between the valve bodies can be made extremely small.
Smooth sliding characteristics can be obtained without causing linking.

Further, carbon is uniformly dispersed so as to form a continuous phase with an aggregate composed of silicon carbide and silicon nitride,
Further, since the particle diameter of each component constituting the composite ceramic is very small, the hardness and strength are higher and the abrasion is less likely to occur as compared with the porous ceramic in which the open pores are impregnated with carbon. Further, even if it is worn, the sliding contact surface can be worn evenly. Furthermore, since the carbon is evenly dispersed and contained in the interior, the slidability can be maintained for a long period of time because carbon is always present on the sliding contact surface even if abrasion occurs. Moreover, the other valve body made of metal or ceramics is not easily worn.

[0014]

EXAMPLES Examples of the present invention will be described below. The same parts as those in the conventional example are designated by the same reference numerals.

FIG. 1 is a view showing only a valve body which constitutes a facet valve 10 which is an example of a disc valve according to the present invention. These fixed valve body 30 and movable valve body 20 are in sliding contact surface 21 with each other. , 31 to be in contact with each other, and by moving the movable valve body 20, the mutual valve bodies 20, 30
The fluid passages 22 and 32 provided in the above are opened and closed to adjust the flow rate of the supply fluid.

As shown in FIG. 2, the movable valve body 20 is made of metal or ceramics. The metal that can form the movable valve body 20 is preferably hard metal such as brass, stainless steel, or cemented carbide in consideration of corrosion resistance and the like, and the ceramics include alumina, zirconia, silicon carbide, A sintered body containing silicon nitride as a main component and containing a predetermined amount of additives is used. For example, for alumina, CaO, SiO ₂ , MgO, T
At least one of iO ₂ , C, B, B ₄ C, Al ₂ O ₃ , Y ₂ O _3, etc. for silicon carbide, and periodic table 2a and 3a elements for silicon nitride. The above oxides and nitrides are added as sintering aids, and stabilizers such as Y ₂ O ₃ , CaO, MgO, and CeO ₂ are added to zirconia.

In order to prevent abrasion and deformation in a short period of time, Vickers hardness of 1000 kg is preferable.
It is better to use a metal or ceramics having a thickness of / mm ² or more.

However, the above-mentioned hardness does not necessarily have to be satisfied, and depending on the purpose of use and environment of use, Vickers hardness of 10
Even if it is less than 00 kg / mm ² , any metal or ceramic having excellent corrosion resistance may be used.

The sliding contact surface 21 has a center line average roughness (R
a) Form a smooth surface of 0.5 μm or less. this is,
This is to prevent the sliding contact surface 31 of the fixed valve body 30 from being worn during sliding, and preferably has a surface roughness (Ra) of 0.1.
An extremely smooth mirror surface having a surface roughness (Ra) of 0.02 μm or less is preferable.

Further, in order to improve the sealing property, the sliding contact surface 21 is a surface having a flatness of 1 μm or less and excellent in flatness,
The number of voids existing on the sliding contact surface 21 is minimized.
The void occupancy rate is preferably 10% or less.

On the other hand, the fixed valve body 30 is, as shown in FIG.
The movable valve body 20 is formed of a composite ceramic material of carbon, silicon carbide, and silicon nitride, and is a counterpart member.
In order to prevent abrasion, the sliding contact surface 31 is finished to have a center line average roughness (Ra) of 1.0 μm or less. Further, it is preferable that the flatness is 1 μm or less in consideration of sealing property and the like.

The above composite ceramic is one in which carbon, which is a self-lubricating substance, is uniformly dispersed between crystal grains of an aggregate composed of silicon carbide and silicon nitride, and each component has a microstructure in which a continuous phase is formed with each other. Have Therefore, the carbon present on the sliding contact surface 31 can reduce the friction coefficient between the valve bodies 20 and 30. Moreover, since the carbon is strongly bonded to the surrounding silicon carbide and silicon nitride and is uniformly present, the carbon does not fall off during sliding, and the carbon alone does not wear first. The slidability and sealability can be maintained for a long period of time. The self-lubricating substance mentioned here is a substance that can be smoothly slid without oil supply.

By the way, it is important that the content of carbon dispersed in the above composite ceramic is in the range of 2 to 30% by weight. Here, the carbon content is set to 2 to 30% by weight because if the content is less than 2% by weight, the amount of carbon present in the sliding contact surface 31 is too small, so that the lubricating effect of carbon is sufficient. This is because the friction coefficient between the valve bodies 20 and 30 cannot be reduced and linking occurs as a result, and conversely, if the content exceeds 30% by weight, it is another component. This is because the content and the content of silicon carbide and silicon nitride are too small, so that the strength and hardness of the entire composite ceramic are lowered, and the abrasion of the sliding contact surface 31 is promoted.

Further, in order to reduce the wear of the movable valve body 20 which is the other member as much as possible while maintaining the low friction coefficient, the average crystal grain diameter of each component of carbon, silicon carbide and silicon nitride is 30 μm or less. To do.

That is, among the components constituting the composite ceramics, any one component has an average crystal grain size of 30.
When it is larger than μm, the surface roughness of the sliding contact surface 31 becomes large, and the movable valve body 20 as the mating material is worn in a short period of time, and the sliding contact surface 31 is slid along with the sliding movement of the movable valve body 20.
This is because the fixed valve body 30 itself is worn out.

Further, the porosity of the composite ceramics is 15
% Or less, preferably 0.5% or less. That is, if the porosity is larger than 15%, the mechanical strength and hardness of the composite ceramics are reduced, so that the movable valve body 20 is damaged when it is pressed, or the movable ceramic body 20 slides with the movable valve body 20 in a short period of time. Because it will be worn.

The content of silicon nitride and silicon carbide forming the composite ceramic is such that silicon nitride is 7 to 66% by weight.
And silicon carbide is contained in the range of 4 to 91% by weight, respectively. However, as the carbon content increases, the strength of the composite ceramic itself decreases significantly. Therefore, when the carbon content is high, it is preferable to increase the silicon nitride content in order to suppress the strength decrease of the composite ceramic.

On the other hand, in order to manufacture the fixed valve body 30 made of the above composite ceramics, α-SiC powder or β-Si is used.
One of C powders or a SiC powder obtained by mixing these is used as a main raw material, and carbon powder such as carbon black or graphite is added as an additive to this SiC powder, or a resole-type phenol resin or coal tar capable of generating carbon during thermal decomposition. Granules are produced by adding powders such as pitch and sucrose or a boron-containing compound of B ₄ C sugar in an amount of 10% by weight or less, kneading and drying. Then, the obtained granules are molded by a conventional molding method such as mold molding, rubber press molding, cast molding, extrusion molding, hot isostatic press molding (HIP), hot press molding,
If necessary, cutting is performed to form a disc-shaped body. Next, the disc-shaped body, which has been calcined in an N ₂ atmosphere to generate carbon from a carbon-forming compound such as a resol-type phenol resin, and further calcined, has the following reaction formula [reaction formula] 3SiC + 2N ₂ → Si ₃ N _As shown by ₄ + 3C, firing is performed in an atmosphere in which silicon nitride and carbon can be generated by the reaction between silicon carbide and nitrogen. In particular,
Firing temperature 1000 ° C., especially 150 in vacuum N ₂ atmosphere
At a temperature of 0 ° C or higher and a gas pressure of 50 atm or higher, especially 1
By firing under high temperature and high pressure of 000 atm or more, a valve body made of a composite ceramic in which three phases of carbon, silicon carbide, and silicon nitride form continuous phases with each other can be obtained. Further, the carbon content rate and the average crystal grain size of each component constituting the composite ceramics depend on the firing temperature and the firing time.
To 30% by weight, and the average crystal grain size of each component may be appropriately adjusted so as not to exceed 30 μm.

Although the movable valve body 20 is made of metal or ceramics and the fixed valve body 30 is made of composite ceramics in the above embodiment, conversely, the movable valve body 20 is made of composite ceramics. The fixed valve body 30 may be made of metal or ceramics, or only the sliding contact surfaces 21, 31 of either one of the valve bodies 20, 30 may be made of composite ceramics.

In the embodiment of the present invention, only the example of the faucet valve is shown, but it goes without saying that it can be used for various disc valves such as a medical sampling valve and a chemical liquid valve.

Example 1 A specific example of a valve body made of the composite ceramics according to the present invention will be shown below.

Purity 99.7%, average crystal particle size 0.1
To β-SiC powder of about 0.4 μm, 20% solution of resol-type phenol resin as a binder for molding and acetone as a solvent were added in appropriate amounts, and kneaded and dried to produce granules. Was used to mold a disc-shaped body at a molding pressure of 2000 kg / cm ² .
After calcination in N ₂ atmosphere, vacuum N
Firing temperature 1800-2000 ° C, gas pressure 2 in ₂ atmospheres
The valve body was manufactured by firing at 000 atm, grinding and polishing the sliding contact surface.

Here, the total amount of silicon and the amount of carbon of the obtained valve body were measured based on the chemical analysis method of a silicon carbide abrasive (JIS R6124), and then the total amount of nitrogen was measured by the LECO method. The following reaction formulas, [reaction formula] The contents of carbon, silicon nitride, and silicon carbide were measured based on 3SiC + 2N ₂ → Si ₃ N ₄ + 3C. Further, the average crystal grain size and porosity of each component constituting this composite ceramic, and the physical properties such as hardness (Vickers hardness) and bending strength (four-point bending) were also measured.

The respective measurement results are as shown in Table 1. In addition, in Table 1, the same measurement was performed for other examples of the present invention in which the carbon content and the average crystal grain size of each component constituting the composite ceramic were changed, and for comparative examples outside the range of the present invention. , And the results are shown respectively.

[0035]

[Table 1]

[Experimental Example 1] Here, the sample N shown in Table 1 was used.
o. 1-5 composite ceramics according to the present invention and sample N
o. Using the composite ceramics of Comparative Examples 6 and 7, the sliding characteristics were measured with a ball-on-disk.

The composite ceramic of each sample has an outer diameter of 40 m.
m and a thickness of 10 mm, each of which is formed into a disc-shaped body, and an aluminum fixing pin is attached to the disc-shaped body at 30 kg / cm ²
The friction coefficient was obtained from the contact load and the frictional force when the disc-shaped body as a sample was rotated for a certain period of time by pressing with the force of 1 and the specific wear amount of each sample and the fixing pin was also measured. The criteria for this measurement and evaluation are that the friction coefficient is 0.7 or less, the specific wear amount of the disk-shaped body is 0.1 mm ³ / kg / km or less, and the specific wear amount of the fixing pin is 0.45 mm ³ / kg.
/ Km or less and satisfying all of these were considered excellent.

The results are shown in FIG.

As can be seen from FIG. 4, sample N which is a comparative example.
o. In the composite ceramic of No. 7, since the carbon content was less than 2%, the lubricating effect of carbon was not sufficiently obtained.
As a result, the friction coefficient could not be reduced to the reference value of 0.7 or less. Moreover, the specific wear amount of the fixing pin, which is the mating member, was as great as 1.0 mm ³ / kg / km or more, and the standard value was not satisfied.

On the other hand, the sample No. which is a comparative example. In the composite ceramic of No. 6, the carbon content is in the range of 2 to 30% by weight, so that the friction coefficient satisfies the standard value,
Since the average crystal grain diameter of each component constituting this composite ceramic is 30 μm or more, the surface accuracy of the sliding contact surface is poor,
As a result, the fixing pin, which is the mating member, is greatly worn, and the reference value (specific wear amount of the fixing pin) is 0.45 mm ³ / k.
It was not possible to satisfy g / km or less. Moreover,
Due to the large particle size of each component, the wear of the composite ceramics itself is severe, and the specific wear amount of the disk is 0.1m which is the standard value.
It could not be set to m ³ / kg / km or less.

On the other hand, the sample No. The composite ceramics according to the present invention of 1 to 5 all have a carbon content of 2 to 3
In the range of 0% by weight, and since the average crystal particle size of each component is 30 μm or less, the friction coefficient is 0.7 or less, and the specific wear amount of the disk-shaped body is 0.1 mm ³ / kg / km or less. ,
Moreover, the specific wear amount of the fixed pin is 0.45 mm ³ / kg / Km
The following were all satisfied.

In addition, the sample No. 1, 2,
Looking at the composite ceramics Nos. 4 and 5, it can be seen that the friction coefficient can be reduced as the carbon content increases. However, as the carbon content increases, the strength and hardness tend to decrease, and when the carbon content becomes 30 wt% or less, the strength becomes 200 MPa or less. Is preferably up to 30% by weight.

Further, sample No. 1 according to the present invention. The composite ceramics of Nos. 2 and 3 and the sample No. which is a comparative example. Comparing the composite ceramics of No. 6 with each other, as the average crystal grain diameter of each component constituting the composite ceramics increases, the amount of wear of the mating material tends to increase, and the wear of the composite ceramics itself tends to increase. Sample No. Since the composite ceramic of No. 6 has a hardness of 700 kg / mm ² or less, the composite ceramic itself is heavily worn. Therefore, the average crystal grain size of each component is preferably 30 μm or less.

[Experimental Example 2] Next, a fixed valve body 30 was formed from the composite ceramics of the present invention and the comparative example shown in Table 1, and the movable valve body 20 sliding relative to the fixed valve body 30 was made of alumina. The Faucet valve 10 shown in FIG. 1 made of ceramics was prototyped, and sliding experiments were conducted on each fixed valve body 30.

Faucet valve 1 used in this experiment
0 is a movable valve body 20 in which a disc-shaped body having an outer diameter of 30 mm and a thickness of 10 mm is provided with a fluid passage 22 having a diameter of 5 mm, and a disc-shaped body having an outer diameter of 40 mm and a thickness of 8 mm has a fluid passage 32 having a diameter of 5 mm. It was configured by combining with the fixed valve body 30 that was drilled.

The sliding contact surface 21 of the movable valve body 20 has a flatness of 1 μm and the center line average roughness is 0.2 μm, and the sliding contact surface 31 of the fixed valve body 30 has a flatness of 1 μm. The center line average roughness was 1.0 μm.

While the solid valve element 30 of each sample is pressed against the alumina movable valve element 20 by the casing with an axial force of 30 kgf, the fluid passages 22 and 32 are heated to 80 ° C.
Hot water is injected at a pressure of 1 kg / cm ² , and the movable valve body 20
The operation load required to slide the control lever 40 was measured.

However, the evaluation criteria in this test were that the sliding property was judged to be good when the load of the operating lever 40 when the movable valve body 20 was slid 10,000 times was 2.0 kg or less. The respective results are shown in FIG.

As can be seen from FIG. 5, sample N which is a comparative example.
o. In the case of using the composite ceramic of No. 7, since the carbon content is less than 2% by weight, the load of the operation lever 40 was 2.0 kg or more after sliding 5000 times.

Further, the sample No. which is a comparative example. In the composite ceramic of No. 6, since the carbon content is in the range of 2 to 30% by weight, the load of the operating lever 40 can be set to 2.0 kg or less even after sliding 10,000 times.
It was not suitable to use this composite ceramic in the facet valve 10 because the wear of the fixed valve body 30 itself is severe.

On the other hand, the sample No.
The composite ceramics 1, 2, 4, 5 were able to keep the load of the operating lever 40 at 2.0 kg or less even after sliding 10,000 times, and had good slidability.

[0052]

As described above, according to the present invention, one valve body constituting a disc valve is formed of metal or ceramics, and the other valve body is dispersed with carbon in an aggregate composed of silicon carbide and silicon nitride. Formed from the contained composite ceramics, smooth sliding properties can be obtained without causing linking, and the wear of both valve bodies can be significantly reduced, so good sliding properties can be obtained even after long-term use. can get.

[Brief description of drawings]

FIG. 1 is a perspective view showing a facet valve which is an example of a disc valve according to the present invention.

FIG. 2 is a perspective view showing a movable valve body in FIG.

3 is a perspective view showing a fixed valve body in FIG. 1. FIG.

FIG. 4 is a graph showing the sliding characteristics of the composite ceramics of the present invention and a comparative example using a ball-on-disk.

FIG. 5 is a graph showing a sliding load when a disk valve is formed by using the composite ceramics of the present invention and a comparative example.

6A and 6B are perspective views showing a facet valve which is an example of a general disc valve.

[Explanation of symbols]

 20: Movable valve body 21: Sliding contact surface 30: Fixed valve body 31: Sliding contact surface 40: Operation lever

Claims (1)

[Claims] 1. One of the valve bodies that slide with each other is formed of metal or ceramics, and the other valve body has carbon uniformly dispersed in an aggregate of silicon carbide and silicon nitride within a range of 2 to 30% by weight. Disc valve that contains.