JPH06300161A - Plunger for solenoid valve and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a plunger for a solenoid valve which has excellent sealing property a high antiadhesion effect, and low swelling property in addition to fundamental characteristics, such as heat resistance and durability and to provide manufacture thereof. CONSTITUTION:In a plunger for a solenoid valve having a plunger body 1 and a seal part 2 made of rubber in various shapes attached to one tip part of the plunger body, the plunger for a solenoid valve having the seal part 2 the whole surface of which is covered with a fluororesin sheet 7 and manufacture thereof are provided. Since the whole surface of the seal part is covered with fluororesin sheet having low swelling property and a high antiadhesion effect, a plunger for a solenoid valve having a low size change, excellent controllability, and a high antiadhesion effect is provided. Further, the use of a soft fluororesin sheet causes provision of an advantage wherein the damage of sealing property is prevented from occurring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid valve plunger and a method of manufacturing the same, and more particularly to a solenoid valve plunger having a good sealability and anti-adhesion property in a sealing portion and having a small swelling property, and a method of manufacturing the same. Is.

[0002]

2. Description of the Related Art Plungers for solenoid valves are, as shown in FIGS.
It has a structure in which a metal seal body 2 is provided on a plunger body 1 made of metal and is incorporated in a fluid control device.
The flow rate control device has a structure in which a solenoid valve plunger is housed in a case 3 having a fluid inlet 31 and an outlet 32. The solenoid valve plunger is a valve of the fluid inlet 31 by a spring 4. The fluid is blocked by being pressed by the seat portion 33. This solenoid valve plunger is movable in its axial direction, and is separated from the valve seat portion 33 by the action of the electromagnetic solenoid 5 to be in an open state.

The solenoid valve plunger as described above has no dimensional change due to the fluid (because the gap between the valve seat and the plunger changes and precise flow rate adjustment is not possible), and the seal portion 2 is attached to the valve seat 33. It is required that it does not stick and that there is no leakage during sealing.

For example, in the case of a plunger for automobile,
As a rubber material for the seal portion, gasoline-resistant ternary fluororubber is often used in order to reduce dimensional change due to swelling of gasoline. However, when controlling the fluid in a minute gap, a slight dimensional change may greatly affect the performance. Alcohol added to gasoline and MTBE (methyl tert-butyl ether)
As the content increases, swelling tends to increase, and there is a drawback that dimensional change increases.

On the other hand, the above-mentioned ternary fluororubber has a drawback that it tends to stick. As a measure to prevent the adhesion, a fluororesin coating film 6 is provided on the surface of the seal portion 2 as shown in FIG. However, the fluororesin coating film 6 has the drawback that it is hard and the surface irregularities are likely to become large, so that the sealing property is reduced, and the film thickness is as thin as about 5 to 20 μm, which causes a problem in abrasion resistance. Was occurring.

The present invention has been made in order to solve the above-mentioned problems, and in addition to basic characteristics such as heat resistance and durability, it is further excellent in sealing property, has a great effect of preventing sticking, and has a swelling property. An object of the present invention is to provide a plunger for a solenoid valve having a small feature and a manufacturing method thereof.

[0007]

In order to solve the above problems, a solenoid valve plunger according to the present invention is provided with a plunger body and a rubber having various complicated shapes provided at one end of the plunger body. In a plunger for a solenoid valve having a seal portion made of, the entire surface of the seal portion is covered with a fluororesin sheet.

In the method of manufacturing a plunger for a solenoid valve according to the present invention, a step of drawing a fluororesin sheet in conformity with the outer shape of the seal portion for preforming, and the fluororesin sheet having the depressed portion is placed at a predetermined position in the mold. , A step of molding unvulcanized rubber in the recess of the preformed fluororesin sheet, a step of installing a plunger body in the unvulcanized rubber, a step of vulcanizing the unvulcanized rubber It is characterized by including.

According to the present invention, since the entire surface of the seal portion is covered with the fluororesin sheet which has a small swelling property and a large adhesion preventing effect, the dimensional change is small, the controllability is good, and the solenoid valve having a large adhesion preventing effect is large. Can provide a plunger for. Furthermore, by using a soft fluororesin sheet, the internal rubber elasticity can be fully utilized, and there is an advantage that the sealing performance is not impaired.

Further, according to the method for manufacturing the solenoid valve plunger of the present invention, there is an advantage that the solenoid valve plunger as described above can be easily manufactured.

[0011]

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 is a sectional view of a specific example of a plunger for a solenoid valve according to the present invention. As is clear from this figure, the plunger for a solenoid valve according to the present invention has a plunger body. A seal portion 2 made of rubber is provided at the tip of the seal member 1, and the entire surface of the seal portion 2 is covered with a fluororesin sheet 7.

As the plunger main body 1, magnetic metal is used for solenoid valves, but the present invention is not limited to this, and it may be made of plastic. For example, what is called engineering plastic or super engineering plastic can be used. Examples of these include PPS (polyphenylene sulfide) and 66 nylon. Various materials may be added to such plastics. For example, a filler or the like can be added.

As described above, the fluororesin sheet 7 covering the entire surface of the seal portion 2 is provided to improve the anti-adhesion property and the swelling resistance without deteriorating the sealing property. The thickness of such a sheet 7 is preferably 100 to
It is preferably 500 μm. The thickness of the sheet is adjusted depending on the sheet material, the drawing depth of the sheet or the shape of the seal portion.

According to the method for manufacturing a solenoid valve plunger according to the present invention, as shown in FIG. 2, the fluororesin sheet 7 is placed in the lower mold 8 having the recess 81 having the shape of the seal portion 2, and the upper mold is provided. Then, the fluororesin sheet 7 is preformed by a die 10 with a die 9 to form the outer shape of the sheet portion (FIG. 3).

Next, the unvulcanized rubber 11 is injected into the concave portion 71 formed by the die 10 (FIG. 4), the plunger body 1 is set, vulcanized, and the seal integrated with the fluororesin sheet 7 is formed. Form part 2 (FIG. 5). Further, the produced ear 72 is cut to form a solenoid valve plunger.

According to such a manufacturing method of the present invention, the fluororesin sheet 7 can be easily coated on the entire surface of the rubber seal portion even if the seal portion 2 has a complicated shape.

[0017]

EXAMPLE As shown in FIGS. 2 to 5, a thickness of 500 μm
The PTFE-based fluororesin sheet is placed in a lower mold 8 having a recess 81 in the shape of a seal portion 2, covered with an upper mold 9, and the PTFE-based fluororesin sheet 7 is preformed by a die 10 to form a sheet part. The outer shape was formed (Fig. 3).

Next, the unvulcanized ternary fluororubber 11 is injected into the recess 71 formed by the die 10 (FIG. 4), and the ferritic stainless steel plunger body 1 is installed and vulcanized (FIG. 4). 5). Further, the resulting ear 72 was cut to manufacture a solenoid valve plunger.

The manufactured solenoid valve plunger was replaced with fuel C: methanol = 80: 20 (volume ratio).
FIG. 6 shows the result of measurement of dimensional change (length after immersion-original length (l ₂ -l ₁ )) when immersed in the solution (40 ° C.). In the figure, Δ indicates the one using the conventional fluororesin coating film, and ○ indicates the plunger of the present invention. It can be seen that the plunger according to the present invention exhibits better swelling resistance than the conventional one.

Next, the adhesive strength was tested. The test conditions were a contact area of 100 mm ² and 24 at 85 ° C and 95% humidity.
The adhesive strength (kN) was measured after standing for 125 hours and at room temperature for 24 hours and at room temperature for 2 hours.

FIG. 7 is a graph showing the results, in which A is ternary fluororubber only, B is ternary fluororubber coated with fluororesin, and C is the plunger manufactured according to the present invention. Indicates. As a result, it was found that the plunger according to the present invention has a good anti-sticking property.

FIG. 8 shows the results of measuring the amount of leakage (sealing property) under a negative pressure of −140 mmHg and the pressing force itself. A in the figure
Indicates a ternary fluororubber only, B indicates a ternary fluororubber coated with a fluororesin, and C indicates a plunger manufactured according to the present invention. As is clear from this result, it was found that the plunger according to the present invention has a good sealability.

[0023]

As described above, according to the plunger for solenoid valve and the method for manufacturing the same according to the present invention, since the entire surface of the seal portion is covered with the fluororesin sheet which has a small swelling property and a large anti-adhesion effect, the dimensions can be reduced. It is possible to provide a plunger for a solenoid valve that has a small change, good controllability, and a large anti-sticking effect. The use of a softer fluororesin sheet also brings about an advantage that the sealing property is not impaired.

Further, according to the method of manufacturing the plunger for the solenoid valve of the present invention, there is an advantage that it is possible to easily manufacture the one having the seal portion having the complicated shape as described above.

[Brief description of drawings]

FIG. 1 is a sectional view of a solenoid valve plunger of the present invention.

FIG. 2 is a sectional view for explaining a method for manufacturing a solenoid valve plunger of the present invention.

FIG. 3 is a cross-sectional view for explaining the method of manufacturing the solenoid valve plunger of the present invention.

FIG. 4 is a sectional view for explaining a method for manufacturing a solenoid valve plunger of the present invention.

FIG. 5 is a cross-sectional view for explaining the method of manufacturing the solenoid valve plunger of the present invention.

FIG. 6 is a view showing a result of measuring a dimensional change of the solenoid valve plunger of the present invention.

FIG. 7 is a diagram showing the results of measuring the adhesive force of the solenoid valve plunger of the present invention.

FIG. 8 is a diagram showing the results of measuring the sealability of the solenoid valve plunger of the present invention.

FIG. 9 is an explanatory diagram of a solenoid valve.

FIG. 10 is a sectional view of a conventional solenoid valve plunger.

FIG. 11 is a side view of a conventional solenoid valve plunger.

FIG. 12 is a side view of a conventional solenoid valve plunger.

[Explanation of symbols]

 1 Plunger body 2 Seal part 6 Fluororesin coating 7 Fluororesin sheet 71 Seat recess 11 Unvulcanized rubber

Claims (2)

[Claims] 1. A solenoid valve plunger having a plunger body and a rubber-made seal portion of various complicated shapes provided at one end of the plunger body, wherein the seal portion is entirely covered with a fluororesin sheet. A solenoid valve plunger characterized by being covered. 2. A step of preforming a fluororesin sheet in accordance with an outer shape of a seal portion, a step of molding an unvulcanized rubber in a recess of the preformed fluororesin sheet, and a step of forming an unvulcanized rubber in the unvulcanized rubber. A method for manufacturing a plunger for a solenoid valve, comprising a step of installing a plunger body and a step of vulcanizing the unvulcanized rubber.