JPH05154640A - Method for making surface of valve member porous - Google Patents

Abstract

PURPOSE:To form the optional porosity at low cost and high yield of a material without any pollution in a method for making the surface of a valve member used to oil impregnation porous. CONSTITUTION:The valve member 1 is arranged in a mold 2 while forming a gap S between a sliding part of the valve member 1 and the mold 2. Mixed material of plural kinds of powders 3L, 3H having different m.p. is filled into the gap S. Thereafter, the mixed material is heated to the temp. of the m.p. or higher of-the low m.p. powder 3L, and the low m.p. powder 3L is melted, and based on this melting, by sticking the high m.p. powders 3H to each of the others, the porous part is formed at the sliding part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for making a surface of a valve member porous, and more specifically, to a sliding member of at least one of a valve body and a valve seat which are slidable with respect to each other. The present invention relates to a method for making a valve member surface porous by forming a porous portion for oil impregnation.

[0002]

2. Description of the Related Art In a valve structure (plug structure) such as a gas cock, grease is generally used for sealing a sliding portion between a valve body and a valve seat. However, the grease deteriorates over time and hardens, and the sealing performance deteriorates. Therefore, the oil having a good compatibility with grease (for example, castor oil) is impregnated in the valve body, and the impregnated oil is continuously exuded to avoid the deterioration of the sealing performance. And the impregnation of the valve body with oil is
Conventionally, a metal such as brass is sprayed on a sliding portion of a valve body to form a porous portion, and the porous portion is impregnated with oil.

[0003]

When forming a porous portion for impregnating oil on the surface of a valve member such as the valve body by carrying out the thermal spraying of the metal, it is not necessary to spray the metal. Since thermal spraying equipment (including auxiliary equipment such as a power source and a gas source) is required, there is a problem that the manufacturing cost of the valve member such as the valve member becomes high. In addition, there is a problem that there is a metal that does not adhere to the surface of the valve member in the process of spraying the metal, resulting in material loss and poor yield, and the non-adhesive metal is scattered to cause dust pollution. .. Further, when it is desired to change the properties of the porous portion formed on the surface of the valve member, there is no choice but to fundamentally change the thermal spraying conditions of the metal, and there is a problem that the change is generally troublesome. The present invention has been made by paying attention to the actual situation, and an object thereof is to provide a means capable of solving the above problems all at once.

[0004]

In the method for making a valve member surface porous according to the present invention, the valve member is arranged with respect to the mold while forming a gap between a sliding portion of the valve member and the mold. In addition, after filling the gap with a mixture of a plurality of powders having different melting points, the mixture is heated to a temperature equal to or higher than the melting point of the low melting point powder to melt the low melting point powder, and the melting The porous portion is formed in the sliding portion by adhering the high melting point powders to each other based on the above.

[0005]

According to the method of the present invention, the gap is formed between the sliding portion of the valve member and the mold, the mixture of the powder is filled in the gap, and the mixture is heated as described above. By doing so, the porous portion can be easily formed in the sliding portion without using a large-scale equipment such as a conventional thermal spraying equipment. Further, all the mixture filled in the gap comes to adhere to the sliding portion due to the adhesion, so that neither material loss nor material scattering as in the conventional case occurs. Furthermore, when it is desired to change the properties of the porous portion formed on the surface of the valve member, the change can be made simply by changing the conditions such as the particle size and mixing ratio of the mixture and the heating temperature that can be easily changed.

[0006]

As described above, since the porous portion can be formed without using large-scale equipment such as the conventional thermal spray equipment, the manufacturing cost of the valve member can be kept low as compared with the conventional one. The cost problem will be solved. Further, since the mixture comes to adhere to all the sliding parts, the generation of material loss is suppressed, the conventional problem of poor yield is solved, and the material does not scatter, so dust pollution also occurs. It will not occur. Further, the property of the porous portion formed on the surface of the valve member can be changed by simply changing the condition that can be easily changed, and the change of the property can be easily performed.

[0007]

EXAMPLES Examples of the present invention will be described below. In FIG. 1 (a), reference numeral 1 denotes a valve body as an example of a valve member in which a porous portion for oil impregnation is formed in a sliding portion by applying the method of the present invention. Has a substantially weight shape, and the mother body is made of a casting (cast iron) that is cast in a state in which the through hole 1a exists in the lateral direction of the central portion.

The outer peripheral portion 1b of the valve body 1 corresponds to the sliding portion with the valve seat (not shown), and the sliding portions of the valve body 1 and the valve seat are both. The valve structure (plug structure) such as a gas cock is constructed by being assembled in contact with each other. In addition, through holes corresponding to the through holes 1a of the valve body 1 are formed in the valve seat at two places on the circumference (two opposite positions that are offset by 180 degrees).

When opening and closing the valve structure having such a structure, the through hole 1a of the valve body 1 and the through hole of the valve seat are appropriately rotated by rotating the valve body 1 with respect to the valve seat in a fixed state. And a state where the through hole 1a of the valve body 1 and a through hole of the valve seat do not coincide (closed state) are selectively exposed, and the opening / closing operation is performed. It is supposed to be done.

Grease is used to seal the sliding portion between the valve body 1 and the valve seat. To prevent deterioration of the grease (aging) and prevent deterioration of the sealing performance, the valve body is used. A porous portion is formed on the sliding portion of No. 1 and the porous portion is impregnated with oil having a good compatibility with grease (for example, castor oil), and the impregnated oil is continuously exuded. The porous portion is formed in the sliding portion of the valve body 1 by the procedure shown in FIGS.

First, a mold 2 is prepared for carrying out the method of the present invention. The mold 2 is a mold formed of a heat-resistant material and formed in a container shape having an upper surface opening. The inner surface shape of the mold 2 is set so that a gap S, which is a space in which the porous portion is to be formed, is formed between the two in a state where the valve body 1 is arranged in the mold 2. ing.

By loading the valve body 1 into the mold 2 as shown in FIG. 1B, the valve body 1 and the mold 2 are inserted.
The gap S is formed between and. Then, in the gap S, a mixture of plural kinds of powders 3L and 3H having different melting points is shown in FIG.
Fill as shown in (c). The mixture is, for example, brass having a particle size of about 10 μm (melting point: 895 to 955 ° C.)
Powder 3H and powder 3L of zinc (melting point: 419 ° C.) having a particle size of about 10 μm and a melting point lower than that of brass 2
It is a mixture of seed powders. The mixing ratio is set so that the brass has a volume ratio of more than half. Then, it is heated to a temperature equal to or higher than the melting point of the low melting point powder 3L (when the low melting point powder 3L is zinc powder, 419 ° C. or higher) to melt the low melting point powder 3L, and the melting After the high melting point powder 3H is adhered to each other based on the above, the porous portion is formed on the outer peripheral surface 1b of the valve body 1 (that is, the sliding portion), and then the porous portion is formed. The valve body 1 is taken out from the mold 2. As a result, as shown in FIG. 2, the valve body 1 in which the sliding portion is made porous is obtained.

If the mixture is pressurized when the mixture is heated, the porous portion will become the valve body 1.
It will come into close contact with, and its adhesion will be improved. When the temperature gradient in the mixture is set so as to decrease from the outer peripheral surface 1b of the valve body 1 to the inner peripheral surface of the mold 2 during the heating, the fusion of the valve body 1 and the porous portion is performed. In addition, the porous portion is formed so as not to collapse in the surface layer. Also, by arbitrarily changing the mixing ratio of the mixture, an arbitrary porous portion can be formed.

Next, another embodiment will be described. The valve member in which the oil impregnated porous portion is formed in the sliding portion may be a valve seat. If it is a valve seat,
Place the valve seat on the base in a leak-proof state (a state that can prevent the mixture from leaking from the gap between the valve seat and the base), and place a core-shaped mold inside the valve seat. To form the gap S, and the gap S is filled with the mixture. After the filling, the same procedure as the above case is performed.

It is also possible that the mixture is a mixture of three or more powders. In that case, the powder having the lowest melting point is heated to a temperature equal to or higher than the melting point of the powder, and the powder having the lowest melting point is melted to bond other powders to each other.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a procedure for carrying out the method of the present invention.

FIG. 2 is a vertical cross-sectional view showing a valve body whose sliding portion is made porous.

[Explanation of symbols]

 1 valve member 2 type 3L, 3H powder S gap

Claims (1)

[Claims] 1. A porous valve member surface for forming a porous portion for oil impregnation in a sliding portion of at least one valve member (1) of a valve body and a valve seat that are slidable with respect to each other. A method for disposing the valve member (1) with respect to the mold (2) while forming a gap (S) between a sliding portion of the valve member (1) and the mold (2), , Powders with different melting points (3
After filling the mixture of L) and (3H) into the gap (S),
The mixture is heated to a temperature equal to or higher than the melting point of the low melting point powder (3L) to melt the low melting point powder (3L), and the high melting point powders (3H) are bonded to each other based on the melting. A method for making a surface of a valve member porous by forming the porous portion in the sliding portion by performing the above.