JPS6334373A - Needle valve - Google Patents

Abstract

PURPOSE:To improve the extent of lubricating ability, by setting material for a needle valve to such one in which fluororesin powder and abrasion resisting inorganic powder both are 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, a mixture of fluororesin powder and abrasion resisting inorganic powder is mixed as much as a weight part of 1-40 into a weight part of 100 of the resin satisfying the following conditions that hardness is HRR70-130 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 resin, nylon resin is used, as for fluororesin, ethylene tetrafluorise resin, and as for the abrasion resisting inorganic resin, molybdenum disulfide powder is usable.

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, conventional needle valves have been used in which a valve body 3 made of fluororubber, which has good wear resistance, elasticity, hardness, and quality 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 1 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 temperature and pressure to form the valve body 3. By adopting such a configuration, the jaw portion 61 of the truncated cone body 6 interferes with the valve body 3, and the loss of tax on the valve body 3 can be prevented.

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 gets into the fuel and metal sockets are susceptible to corrosion, which can cause problems in durability. Therefore, a socket 7) made of synthetic resin with high corrosion resistance is desired instead of metal.

However, as mentioned above, there is no suitable adhesive for fluororubber, so even if the socket 2 were made of synthetic resin, the synthetic resin could be molded as shown in the cross section in Figure 2, and the neck portion 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. Resins that satisfy these characteristics include:
For example, there are super heat-resistant engineering plastics such as polyphenylene sulfide, but the needle valve 1 has extremely small dimensions of around 1 cra, and the socket 2 requires considerable precision. Polymer engineering plastics have a disadvantage in that it is difficult to precisely mold the neck portion 5 or truncated cone body 6 as described above, due to poor moldability and other conditions. 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. It is an object of the present invention 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 1 (RR70 to HR) on the Rockwell scale.
R130, compression modulus is 100-300 Kgf/ll
l1) Adding 100% of the resin to the synthetic resin that satisfies the conditions of 2.
It is characterized in that 1 to 40 parts by weight of a mixture of fluororesin powder and wear-resistant inorganic powder is mixed based on the weight part.

The needle valve according to the present invention has improved warmth by mixing fluororesin powder and 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.

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. may be used. Therefore, there is no need to mold and bond the fluororubber valve body under high temperature and pressure as in the past, so there is no need to use super heat-resistant engineering plastics, and 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 influenced 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 set to 100 to 300 gf/m1)2, and the hardness must be set to Rockwell hardness IIRR-2, as is clear from the examples described below. 70 to HRR-130 is required.

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.
．． It was found that it is necessary to be 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, (1) a compression modulus of 100 to 300 Kgf/ma+2, and a hardness of IIRR to 70 on the Rockwell scale. ~HRR-13
It is necessary to select a synthetic resin that satisfies the following conditions: (1) the coefficient of friction is 0.3 or less;

After considering these matters and conducting repeated experiments with various synthetic resins, the present inventor has determined that the above conditions can be satisfied by mixing fluorine resin powder and wear-resistant inorganic powder into a specified synthetic resin. This discovery led to the present invention. That is, it has heat resistance of 0100℃ or higher, and has a compressive modulus of 100 to 300 Kgf/m.
m2, hardness is IIRR-70 to HR in Rockwell hardness
By using synthetic resin R-130 and mixing a predetermined amount of fluororesin powder and wear-resistant inorganic powder,
It has been discovered that a synthetic resin with a coefficient of friction of 0.3 or less can be produced.

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, fluororesin powder and wear-resistant inorganic powder are mixed into such synthetic resin. This mixture of fluororesin powder and wear-resistant inorganic powder improves the wear resistance by improving the lubricity of the synthetic resin.1. It will be added. That is,
In order to have good performance as a needle valve, the friction coefficient of the valve body portion must be 0.3 or less, but there is a risk that the above-mentioned synthetic resins may not be able to satisfy the above-mentioned lubricity. .

In the present invention, the mixture of the fluorine resin powder and the 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 the mixture 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 the mixture added in consideration of the lubricity, hardness, and elasticity. That is, if the amount of the mixture added is less than 1 part by weight, it is difficult to expect much improvement in lubricity and it is difficult to manufacture a needle valve with excellent performance, while on the other hand, if the amount of the mixture exceeds 40 parts by weight, This is because although the lubricity is sufficient and the hardness is improved, the compressive modulus of elasticity is increased, which may cause problems in liquid sealing properties during pressure welding.

Examples of the above-mentioned fluororesin powder include tetrafluoroethylene resin powder, tetrafluoroethylene-hexafluoropropylene copolymer resin powder, 47-sulfonated ethylene-perfluoroalkyl vinyl ether co-E1 resin powder, and tetrafluoroethylene resin powder. One or more types of fluororesin powders such as ethylene-ethylene copolymer resin powder, polytrifluorochloroethylene resin powder, and polyvinylidene fluoride resin powder can be used.

Examples of wear-resistant inorganic powders include molybdenum disulfide powder, mica powder, glass powder, carbon blank powder, carbonate powder, hydroxide powder, oxide powder,
One or more of powders such as silicate-based powders and sulfate-based powders can be used.

The fluororesin powder and wear-resistant inorganic powder as described above preferably have a particle size of 100 μm or less. When the particle size is larger than 100 μm, it is difficult to uniformly disperse the wear-resistant inorganic powder and the wear-resistant inorganic powder in the synthetic resin.
Moreover, since the amount added is relatively limited, 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, if the pressure contact is less than IIRR-70, the pressure contact permanent set is large, and the pressure contact test of the needle valve causes deformation of the part in contact with the valve seat, resulting in insufficient fluid sealing performance and liquid leakage. . On the other hand, if the hardness exceeds HRR-130, the hardness becomes too hard and becomes brittle, resulting in cracks on the surface due to contact force during the pressure welding test, resulting in liquid leakage. Therefore, the hardness needs to be IIRR-70 to HRR-130.

(2) Compressive elastic modulus (Kgf/vsm2) Similarly, needle valves with various compressive elastic moduli were manufactured and repeated pressure tests were conducted. The results are shown in Table 2.

Table 2 Unit: (Kgf /mva2) × If the compression modulus with leakage is less than 100 Kgf 7mm2,
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 gf/mm2, it becomes too hard and the surface becomes brittle, and the force when the valve body and valve seat come into contact causes cracks in the surface, 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 coefficients of friction and conducting various studies based on the coefficient of friction, as is clear from Table 3 below, those with a coefficient of friction exceeding 0.3 have a large amount of wear. It did not pass the 1 million press contact test. Therefore, it has been found that the coefficient of friction needs to be 0.3 or less.

Table 3 Example 2 Needle valves were manufactured using various synthetic resins with the compositions shown in Table 4.

In Table 4, the unit of compressive elastic modulus is Kgf/men2, the composition of synthetic resin is parts by volume, the fluororesin powder and wear-resistant inorganic powder (particle size 3 μs) are parts by weight, and the pressure welding test is 1
1,000,000 times repeated pressure welding test, alcohol-gasoline test at 60℃ for 2,000 hours? +? The fluororesin powder used was Daikin Industries' Lublon (trade name) with a particle size of 2 μm.

Table 4 [Effects of the Invention] As explained above, in the needle valve according to the present invention, lubricity is improved by mixing a mixture of F-7 resin powder and wear-resistant inorganic powder into a predetermined synthetic resin. As a result, the wear resistance is improved.

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 ... A-head cone,
61...Chin area. Applicant's agent Tadashi Amemiya Season 2 Amendment to Figure Procedure (Spontaneous 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 1 to 40 parts by weight of a mixture of a fluororesin powder and a wear-resistant inorganic powder is mixed into a synthetic resin satisfying the condition of gf/mm^2 per 100 parts by weight of the resin.