JP2538444B2 - Case coating method for electric expansion valve - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for coating a case of an electric expansion valve used in a refrigeration cycle and used in a low temperature atmosphere.

[0002]

2. Description of the Related Art In a solenoid valve, a magnet body M including an electromagnet coil 3, a cover member 5, a stopper 2 and a fixed iron core 1 is used as a solenoid valve 9 in an electrically special resin 9 such as an epoxy resin. It is disclosed that the components such as the electromagnet coil 1, the cover member 5, the stopper 2, the fixed iron core 1, the lead wire 12 and the valve body mounting member 8 are integrally covered by cast coating with the above.

[0003]

According to the above-mentioned conventional technique, the lead wire 12 extends straight upward from the electromagnet coil 1 and is drawn out from the upper portion of the magnet body M through the resin 9 to the outside. Moisture or water adhering to the upper portion of the magnet body M or the lead wire 12 causes the lead wire 12 and the resin 9
There is a problem that it is easy to enter the electromagnet coil 1 from between, and the moisture-proof and waterproof effects are poor.

The present invention has been made in view of the above point, and the upper wall and side portions of the case are covered with a covering material to bury the lead wire in the covering material, and the lead wire take-out portion is a valve of the expansion valve. The present invention relates to a method for covering a case of an electric expansion valve that is not affected by the heat of a low-temperature refrigerant flowing inside the valve body even if it is provided on the body side.

[0005]

According to the present invention, there is provided a stepping motor, a case having an upper wall accommodating the motor, a side portion and an opening, and a lead wire extending from the motor to the outside of the case. A method of coating an electrically driven expansion valve case, comprising: a valve main body part for controlling a flow of a refrigerant from an inlet pipe to an outlet pipe by driving the motor on an opening side of the case, wherein the lead wire is provided on the case. Temporarily fixed so as to extend along the side of the wall toward the opening side of the case, the peripheral wall, the bottom wall, the recess defined by the both walls, and the step-like projection extending over the both walls. And a side wall of the peripheral wall that bulges outwardly to form a casting die having a side path connected to the recess, and the upper wall of the case is placed on the stair-shaped protrusion. The lead wire temporarily stored in the recess is temporarily fixed to the side road side. And then cover the case and the lead wires by pouring a molten insulating material between the peripheral wall and the bottom wall of the casting mold and the case to solidify them. A method for coating an electrically driven expansion valve case, in which the thickness of the formed side portion is made thicker than other covered side portions, and the lead wire lead-out portion is on the valve body portion side. is there.

[0006]

According to the above-mentioned means, the casting mold supports the case when the case is housed in the recess, and at the same time, the projection forms a space between the inner surface of the casting mold and the case, and the recess is formed. Since it forms part of this recess and forms a side path corresponding to the lead wire that comes out of the case, both the case and the lead wire can be cooled by pouring the molten insulating material into the casting mold and cooling it. Coating at the same time, that is,
The lead wire extending from the upper wall of the case can be completely covered with the covering material to expose the lead wire under the case. As a result, a covering material having high waterproof, heat insulating and electrical insulating effects can be obtained. The fixing strength of the lead wire can be improved by the side part that is a part of the covering material. Further, since a part including the bent portion of the lead wire is exposed from the upper part of the case to the outside of the case and is buried above the bottom surface of the thick side part along the side wall of the case, it is added to the lead wire. The tensile stress is dispersed and absorbed by the side portions, and as a result, the tensile stress to the root of the lead wire can be weakened and damage to the root of the lead wire can be prevented.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

In the figure, reference numeral 1 is an electric expansion valve used in a refrigeration cycle of a refrigeration / air-conditioning device such as a refrigerator or an air conditioner, which is composed of a motor section 2 and a valve body 3 provided below the motor section. There is. The motor unit 2 has a box-shaped case 4 made of aluminum, a cover 5 made of stainless steel for closing the lower surface of the case, and a stepping motor 6 housed in the case 4 and driven by receiving a pulse signal. A gear mechanism 8 connected to the shaft 7 of the stepping motor, and a controller (not shown) extending from the stepping motor 6 through the upper wall 4A of the case 4 to the outside of the case 4 and along the side wall 4B of the case 4. It is composed of a plurality of, for example, six lead wires 9 connected to the signal line from. On the other hand, the valve body 3 is fixed to the gear mechanism 8 and is connected to a spindle 11 that penetrates a stopper 10 attached to the cover 5 and the spindle 11.
A valve body 16 which is suspended and supported by a screw-shaped driver 13 which is screwed with the holder 12 and an expandable bellows 14 and which is in abutting relation with the lower end of the driver 13 and has a needle portion 15 at the lower end. And the needle part 1
The valve seat 17 on which the seat 5 is seated, the bent portion 18 formed in the space above the valve seat, and the inlet and outlet pipes 19 and 20 each having one end connected to communicate with the bent portion. It is configured and is connected to the motor unit 2 by a removable lock nut 21.

In the electrically driven expansion valve 1, the stepping motor 6 rotates normally or reversely according to the number of pulse signals sent from the controller, and this rotational movement is caused by the gear mechanism 8 and the spindle 1.
1. The transmission mechanism of the driver 13 converts the reciprocating linear motion into the reciprocating linear movement, which allows the valve body 16 to move in the inserting / removing direction, and separates from the valve seat 17 from the fully closed position where the valve body 16 seats on the valve seat 17. Further, it has a function of controlling the flow rate of the refrigerant up to the fully opened position, that is, both a pressure reducing function and an opening / closing function.

Reference numeral 22 is a coating material made of a heat and electrical insulating material such as rubber or resin for coating the motor portion 2, and has a root 9A of the lead wire 9 and a curved portion 9B curved downward from the root. Then, the side portion 23 is formed to cover the hanging portion 9C along the side wall 4B of the case 4. As shown in FIG. 1, the side portion 23 is thicker than the other portions because it covers the lead wire 9. By covering the motor part 2 with the covering material 22, both the heat insulating and waterproof effects of the motor part 2 used in a low temperature region can be improved. The lead wire 9 is pulled out from the upper wall 4A of the case 4 to the outside of the case because the gear mechanism 8 is located below the motor unit 2.

Next, a method of covering the motor section 2 will be described.

Reference numeral 24 shown in FIGS. 4 to 6 is a bottomed cylindrical casting die having a peripheral wall 25 and a bottom wall 26, the inner surface of which is coated with a release agent, and the upper surface of which is open from the peripheral wall 25 to the bottom wall 26. A bulged portion 27 that is long in the vertical direction is formed in a part of the above, and a side path 29 that forms a part of the recess 28 is formed. Reference numeral 30 is an appropriate number of step-like projections formed to extend over the inner surface of the peripheral wall 25 and the upper surface of the bottom wall 26 and project into the recess 28.
When the motor unit 2 is housed in the recess 28 as shown by the chain line in FIG. 5, the outer surface of the case 4 and the peripheral wall 25 and the bottom wall 26.
The motor unit 2 is supported so as to form a space between the motor unit 2 and the inner surface of the motor unit 2. That is, each of the protrusions 30 serves as a mold contact portion of the motor unit 2 to support the motor unit 2 and to function as a spacer that forms a space. As shown in FIG. 3, the motor portion 2 is preliminarily coated with a band-shaped rust-preventive coating on an annular surface extending from the outer edge of the upper surface of the case 4 facing the protrusion 30 to the upper edge of the peripheral surface. It is formed as a painted surface 31.

When the motor section 2 is housed in the recess 28 of the casting mold 24, first, the lead wires 9 are bound together and attached to the peripheral surface of the case 4 with an adhesive tape or the like, and then the motor section 2 is attached.
In reverse, that is, the upper surface is the lower surface, and the lead wire 9 is the casting mold 2
4 is accommodated in the recess 28 in a state corresponding to the side passage 29, and the coated surface 31 of the motor portion 2 is placed on each protrusion 30. With this mounting, the peripheral wall 25 and the bottom wall 26 of the casting mold 24,
A space is formed between the recess 28 and the motor unit 2, and a molten rubber or resin insulating material is poured into the space formed in the recess 28 in such a state. After the cooling time for hardening, the motor part 2 is pulled out from the casting mold 24 to be welded and integrated with the motor part 2 as shown in FIG. 1, and the motor part and the bent part 9B of the lead wire 9 A dressing 22 with a side 23 covering 9C is obtained. In addition, each projection 30 of the painted surface 31
The surface in contact with is the exposed surface.

According to the above method of covering the case 4, the projection 30 formed on the casting mold 24 has the upper wall of the case 4 when the case 4 is stored in the recess 28 of the casting mold with the case 4 reversed. 4A acts as a spacer that forms a space between the case 4 and the peripheral wall 25 and the bottom wall 26 of the casting mold 24.
On the other hand, one side of the casting mold 24 is connected to the recess 28 and forms a part of the recess to form a side passage 29 corresponding to the lead wire 9. Therefore, the molten insulating material is provided in the space inside the casting mold 24. The lead wire 9 can be simultaneously coated with the case 4 by pouring, and the covering material 22 covering the case 4 and the side portion 23 extending outward from one side of the covering material and covering the lead wire 9 are obtained. The lead wire 9 from the bottom of the case 4 to the outside.
Can be exposed. Further, when the lead wire is covered by using a casting die, in order to firmly fix the lead wire, the lead wire is extended along the side portion from the upper wall of the case toward the opening side of the case, Even if the extension part of is shaped so that it is taken out to the valve body side, the thickness of the side part covered with the lead wire is made thicker than the other covered side parts. Since a predetermined distance can be provided between the valve portion and the valve body portion by the thickness of the side portion, the lead wire is not affected by the low temperature refrigerant flowing through the valve body portion.

[0015]

According to the present invention as described above, the casting die receives and supports the case when the case is housed in the recess, and at the same time, the casting die has a projection that forms a space between the inner surface of the casting die and the case. Along with the formation, it forms a side path that connects to the recess and becomes a part of this recess and corresponds to the lead wire that comes out of the case, so by pouring and cooling the molten insulating material into the casting mold, Both the lead wire and the lead wire can be simultaneously integrated and coated, that is, the lead wire extending from the upper wall of the case can be completely covered with the covering material to expose the lead wire below the case. A coating material having a high electric insulation effect can be obtained, and the side portion which is a part of the coating material can improve the fixing strength of the lead wire. In the present invention, a part including the bent portion of the lead wire is exposed from the upper part of the case to the outside of the case and is buried above the bottom surface of the thick side part along the side wall of the case.
The tensile stress applied to the lead wire is dispersed and absorbed by the side portions, and as a result, the tensile stress to the root of the lead wire can be weakened and damage to the root of the lead wire can be prevented. In the present invention, since the thickness of the side portion coated with the lead wire is made thicker than the other coated side portions, even if the lead wire take-out portion is on the same side as the valve body portion side, Since the lead wire take-out portion is separated from the valve body portion, the lead wire is not affected by the low temperature refrigerant flowing through the valve body portion.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an electric expansion valve covered with a covering material.

FIG. 2 is an overall perspective view of the electric expansion valve before being covered with a covering material.

FIG. 3 is an overall perspective view of a motor unit.

FIG. 4 is a plan view of a casting mold.

5 is a cross-sectional view taken along the line AA in FIG.

FIG. 6 is an overall perspective view of a casting mold.

[Explanation of symbols]

 2 motor part 3 valve body 4 case 9 lead wire 22 covering material 23 side part 24 casting mold 25 peripheral wall 26 bottom wall 28 recess 29 side passage 30 protrusion

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) Bibliography Sho 57-102770 (JP, U) Rikai 56-169515 (JP, U) Japanese Patent Sho 57-7898 (JP, B2)

Claims (1)

(57) [Claims] 1. A stepping motor, a case having an upper wall accommodating the motor, a side portion, and an opening, a lead wire extending from the motor to the outside of the case, and the opening on the side of the opening of the case. A method for coating an electric expansion valve case, comprising: a valve main body that controls the flow of a refrigerant from an inlet pipe to an outlet pipe by driving a motor, wherein the lead wire extends along a side portion from an upper wall of the case. Temporarily fixed so as to extend to the opening side of, the peripheral wall, the bottom wall, the recess defined by the both walls, the step-like projections straddling the both walls, and one side of the peripheral wall. By bulging outwardly, in a casting mold having a side path continuing to the recess, the upper wall of the case is stored in the recess while being placed on the stepwise projection,
And, in a state where the temporarily fixed lead wire is directed to the side road side, after that, by pouring a molten insulating material between the peripheral wall and the bottom wall of the casting mold and the case to solidify, While covering the case and the lead wire, the thickness of the side part covered with the lead wire is made thicker than the other covered side parts, and the lead-out part of the lead wire is on the valve body side. A method for coating an electric expansion valve case, characterized in that