JPS6334372A - Needle valve - Google Patents

Abstract

PURPOSE:To improve the extent of lubricating ability, by making up material for a needle valve with abrasion resisting inorganic powder mixed in synthetic resin. CONSTITUTION:A needle valve 1 is of plastics, provided with a valve body part 3 and a socket part 2, and the valve body part 3 and the socket part 2 are all formed with synthetic resin. As for material, abrasion resisting inorganic powder of a weight part of 1-40 is mixed in a weight part of 100 of the resin satisfying the following conditions that hardness is HRR70-130 is Rockwell hardness and modulus of elasticity is 100-300kgf/mm<2>. Doing like this, lubricating ability is improved, therefore abrasion resistance is improved as well. As for the resin, nylon resin and polyethylene terephthalate are used, and as for abrasion resisting inorganic powder, more than one kind of molybdenum disulfide powder, mica powder, glass powder, etc., can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to needle valves, particularly needle valves used in fluid control of automobiles.

[Technical background of the invention]

As shown in FIG. 1, the needle valve 1 basically consists of a socket 2 and a conical valve body 3, which constitute the main body of the needle valve 1. The valve body 3 is pressed against the valve seat 41 formed in the section.
The fluid is controlled by releasing it.

Since the valve body 3 is repeatedly pressed and released from the metal valve seat 41, it has excellent wear resistance, good durability, and is designed to prevent its shape from changing due to heat. It is required to have heat resistance, and to have appropriate elasticity and hardness so that the shape is stable against mechanical stress caused by pressing and releasing. moreover,
When the needle valve 1 is used as an automobile component, it must satisfy various conditions such as being resistant to gasoline and various oils.

For this reason, conventionally, the needle valve 1 used is one in which a valve body 3 made of fluororubber, which has good wear resistance, elasticity, hardness, and chemical resistance, is attached to a metal socket 2.

However, as is well known, the adhesive strength of the fluororubber is poor, so it has been difficult to maintain sufficient adhesive strength between the metal socket 2 and the fluororubber valve body 3. . For this reason, for example, the second
A needle valve l having a structure as shown in a partially sectional view in the figure has been put into practical use.

That is, a neck portion 5 is formed in the part of the socket 2 where the valve body 3 is attached, and a truncated cone 6 is connected to the neck portion 5 so that the bottom surface of the truncated cone 6 protrudes like a jaw. Then, fluororubber was molded onto this truncated conical body 6 under high pressure and high temperature to form the valve body 3. With this configuration, the jaw portion 61 of the truncated cone body 6 interferes with the valve body 3, thereby preventing the valve body 3 from falling off.

In recent years, especially in foreign countries, alcohol fuel has been used instead of gasoline as an automobile fuel, and fuels that are a mixture of gasoline and alcohol have been used.

Therefore, the aforementioned socket 2 is required to have alcohol resistance. Furthermore, since alcohol has high water absorption and adsorbs a large amount of water, water enters the fuel and metal sockets are susceptible to corrosion, which may cause problems in durability. Therefore, there is a demand for sockets made of synthetic resin with high corrosion resistance in place of metal sockets.

However, as mentioned above, there is no suitable adhesive for fluororubber, so even if the socket 2 is made of synthetic resin, the synthetic resin is molded as shown in the cross section in FIG. 5 and a truncated cone 6 must be formed. Moreover, when attaching the valve body 3 made of fluororubber, it must be molded under high temperature and pressure, so the synthetic resin has good compressive strength and the molding temperature (15
It is necessary to use a synthetic resin that has heat resistance at temperatures above 0°C. Examples of synthetic resins that satisfy these characteristics include super heat-resistant engineering plastics such as polyphenylene sulfide; It is difficult to precisely mold the neck portion 5 or the truncated cone body 6 as described above due to the combination of the following conditions: accuracy is required, and the super heat-resistant engineering plastic has poor moldability. There is a drawback. For this reason, a special molding method is required, and the needle valve 1 having the socket 2 made of synthetic resin has the drawbacks of being extremely expensive and lacking in reliability.

[Summary of the invention]

The present invention has been made in view of the above-mentioned points, and the socket part and the valve body part are all made of ordinary synthetic resin without using super heat-resistant engineering plastics with poor moldability, and the valve is made of fluororubber. The object of the present invention is to provide a needle valve that eliminates various difficulties caused by adhesion between the body and the socket portion.

Therefore, the needle valve according to the present invention is a synthetic resin needle valve having a valve body portion and a socket portion, and has a hardness of HRR70 to HRR on the Rockwell hardness scale.
130, compression modulus is 100-300 Kgf/as
The present invention is characterized in that 1 to 40 parts by weight of wear-resistant inorganic powder is mixed into a synthetic resin that satisfies the conditions of 2, based on 100 parts by weight of the resin.

The needle valve according to the present invention has improved lubricity by mixing a wear-resistant inorganic powder into a predetermined synthetic resin, and as a result, has improved wear resistance. Therefore, it is possible to satisfy the conditions necessary for a needle valve, and there is an advantage that various problems caused by the adhesion between the fluororubber valve body and the socket mentioned above can be eliminated.

[Detailed description of the invention]

According to the present invention, the valve body portion and the socket portion are entirely formed of synthetic resin.

That is, in order to manufacture a needle valve using a synthetic resin, it is necessary to select a synthetic resin that satisfies various conditions required for the needle valve. Therefore, it is clear that it is first necessary to consider what conditions are required for the needle valve.

The present inventors investigated various conditions for the above. In other words, the shape must be heat resistant so that it does not change shape and crack depending on the hot atmosphere under the operating conditions of the needle valve, and it must have elasticity and hardness so that the shape remains stable against the mechanical stress caused by pressing and releasing. It is necessary to satisfy conditions such as having an appropriate value and being resistant to gasoline and alcohol. These conditions will be discussed below.

1. Heat resistance When the needle valve is in operation, the temperature is usually below 100°C.

Therefore, any resin that does not undergo thermal deformation at 100°C is sufficient.Therefore, there is no need to mold and bond the fluororubber valve body under high temperature and pressure as in the past, so it is necessary to use super heat-resistant engineering plastic. Since there is no such thing, ordinary synthetic resins can be used.

2. Shape Stability It has become clear that the shape stability, especially the shape stability of the valve body portion, is greatly affected by the elasticity and hardness of the valve body portion. That is, in order to maintain the shape stability of the valve body part, the compressive elastic modulus must be 100 to 300 Kgf/a+s+", and the hardness must be IIRR-70 to Rockwell hardness, as is clear from the examples described below. II!?R-13
Required to be 0.

3. Chemical resistance For chemical resistance, select a synthetic resin that can satisfy the conditions.

4. Abrasion resistance Abrasion resistance is an important characteristic for needle valves from the viewpoint of liquid sealing properties and durability. This wear resistance can be understood as a problem of the lubricity of the synthetic resin in the hardness range mentioned above, that is, a problem of the coefficient of friction.
This was made clear through study by the inventor. That is, as is clear from the examples described later, the friction coefficient of the valve body portion is 0.
, 3 or less.

In view of the above points, the synthetic resin that can be used in the present invention must have a heat resistance of 0100°C or higher, a compression modulus of 100 to 300 Kgf/me2, and a hardness of Rockwell hardness of IIRR-To. ~IIRR-130
It is necessary to select a synthetic resin that satisfies the following conditions: (1) The coefficient of friction is 0.3 or less.

As a result of considering these matters and conducting repeated experiments on various synthetic resins, the present inventor found that various synthetic resins were
It has heat resistance of 0℃ or higher, and has a compressive modulus of 100 to 30.
0 Kgf / 驕-2, hardness is Rockwell hardness and HR
It was found that although the condition of R-70-11RR-130 was satisfied, the condition of the friction coefficient being 0.3 or less was not satisfied.

Therefore, in the present invention, there is heat resistance above 0100°C, and (1) a compressive elastic modulus of 100 to 300 Kgf/
m Peng 2, the hardness is IIRR-70 on the Rockwell scale!
By using a synthetic resin that satisfies the conditions of 1RR-130 and improving this, we are attempting to manufacture a needle valve made entirely of synthetic resin.

Examples of resins that satisfy these conditions include one or more synthetic resins such as nylon resin, polyethylene terephthalate resin, polybutylene terephthalate resin, and polypropylene resin.

In the present invention, wear-resistant inorganic powder is mixed into such synthetic resin. This wear-resistant inorganic powder is added to improve the wear resistance of the synthetic resin by improving its lubricity. That is, in order to have good performance as a needle valve, the coefficient of dynamic friction of the valve body portion needs to be 0.3 or less, but there is a possibility that the above-mentioned fl lubricity cannot be satisfied with the synthetic resins mentioned above. It is from.

In the present invention, this wear-resistant inorganic powder is added in an amount of 1 to 40 parts by weight per 100 parts by weight of the synthetic resin. That is, when a wear-resistant inorganic powder is added to the synthetic resin, the lubricity and hardness of the synthetic resin improve, but the elasticity tends to decrease. Therefore, it is necessary to control the amount of wear-resistant inorganic powder added in consideration of the lubricity, hardness, and elasticity.

That is, if the amount of the wear-resistant inorganic powder added is less than 1 part by weight, it is difficult to expect much improvement in lubricity, resulting in the disadvantage that it is difficult to manufacture a needle valve with excellent performance. If the powder exceeds 40 parts by weight, the lubricity will be sufficient and the hardness will be improved, but the compression modulus will increase, which may cause problems in liquid sealing during pressure welding.

Such wear-resistant inorganic powders include, for example, molybdenum disulfide powder, mica powder, glass powder, carbon black powder, carbonate powder, hydroxide powder, oxide powder, silicate powder, and sulfate powder. It is possible to use one or more types of powders such as powders such as powders.

The wear-resistant inorganic powder as described above preferably has a particle size of 1
It is preferable that the thickness is 00 μm or less. If the particle size is larger than 100 μm, it will be difficult for the wear-resistant inorganic powder to be uniformly dispersed in the synthetic resin, and the amount added will be relatively limited, so there is a risk that the wear resistance will not be sufficient. .

Examples of the present invention will be described below.

Example 1 (1) Rockwell hardness Needle valves with various Rockwell hardnesses were manufactured, and repeated pressure welding tests were conducted at various Rockwell hardnesses. The results are shown in Table 1.

(Leaving space below) Table 1 As a result of the above, pressure contact permanent set is large when HRR is less than -70, and pressure contact test of needle pulp causes deformation of the part in contact with the valve seat, resulting in insufficient fluid sealing performance and liquid leakage. . If the hardness exceeds IIRR-130, the hardness will become too hard and brittle, resulting in cracks on the surface due to contact force during the pressure welding test and liquid leakage. Therefore, the hardness will be HRR-70-HRR~ Must be 130.

(2) Compressive modulus (Xd/-) Needle pulps with various compressive moduli were similarly produced and subjected to repeated pressure tests. The results are shown in Table 2.

Table 2 If the compression modulus is less than 100 Kgf/as,
The elastic recovery force is poor, causing deformation of the valve body part during the pressure contact test, and the fluid sealing property of the contact example between the valve seat and the valve body is insufficient, causing fluid leakage.

On the other hand, if it exceeds 300 Kgf/2, it will become too hard and the surface will bend, causing cracks in the surface due to the force when the valve body and valve seat come into contact, causing fluid leakage.

(3) Friction coefficient While the valve seat and the valve body are repeatedly pressed against each other, those with high frictional resistance quickly wear out, while those with low resistance gradually wear out, causing deformation of the valve body.

Therefore, as a result of manufacturing needle valves with various II friction coefficients and conducting various studies based on the friction coefficient, as is clear from Table 3 below, those with a friction coefficient exceeding 0.3 have a large amount of wear. , it did not pass the pressure contact test of 1 million times. Therefore, it has been found that the coefficient of friction needs to be 0.3 or less.

Table 3 Example 2 Molybdenum disulfide powder and silica powder were mixed with various synthetic resins in the ratios shown in Table 4, and kneaded in a twin-screw extruder.
It was pelletized by hot cutting.

Using each of the produced pellets, a synthetic resin needle valve was produced by injection molding.

In Table 4, the unit of compressive elastic modulus is Kgf 7mm'', the composition of the synthetic resin is parts by volume, the silica powder and molybdenum disulfide (particle size 3μs+) are parts by weight, and the pressure welding test is 10
00,000 times repeated pressure contact test, alcohol-gasoline property shows the state when immersed at 60°C for 2000 hours.

(The following is a blank space) Table 4 [Effects of the Invention] As explained above, in the needle valve according to the present invention, the lubricity is improved by mixing a wear-resistant inorganic powder into the specified synthetic resin, and as a result, the lubricity is improved. , which improves wear resistance. Therefore, it is possible to satisfy the conditions necessary for a needle valve, and there is an advantage that various problems caused by the adhesion between the fluororubber valve body and the socket mentioned above can be eliminated. That is, the properties required for bonding fluororubber, such as heat resistance and compressive stress, are no longer required, and there is no need to mold a truncated cone, a neck portion, etc. This has the advantage that manufacturing is extremely easy and costs can therefore be significantly reduced.

[Brief explanation of drawings]

Figure 1 is a partial cross-sectional view showing the configuration of the needle valve;
The figure is a partial cross-sectional view of the valve body mounting portion of the needle valve. 1...needle valve, 2...socket, 3...
...valve body, 5 ... neck part, 6 ... truncated cone body,
61...Chin area. Applicant's agent Tadashi Amemiya Hanmizo 2 drawing procedure amendment (dated September 4, 1986)

Claims (1)

[Claims] (1) A needle valve made of synthetic resin that has a valve body part and a socket part, and the hardness is HR on the Rockwell hardness scale.
R70~HRR130, compression modulus 100~300K
A needle valve characterized in that a synthetic resin satisfying the condition of gf/mm^2 is mixed with 1 to 40 parts by weight of wear-resistant inorganic powder per 100 parts by weight of the resin.