JP2001320867A - Water-tight structure of electro-magnetic coil for stepping motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable improvement in resin seal molding property of an electro- magnetic coil in a stepping motor. SOLUTION: The stepping motor comprises an upper side electromagnetic coil portion composed of an electromagnetic coil 4 wound around a bobbin, and a terminal 2 for connecting the coil 4 to a lead wire 30 and a lower side electromagnetic coil portion in the similar structure provided closely at the lower side of the upper side electro magnetic coil portion. The resin seal molding of the electromagnetic coil portion can be executed without depending on the insertion molding process in view of enabling improvement in the seal molding property.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stepping motor, particularly an electric expansion valve for a refrigerating cycle of an air conditioner, a refrigerator, a freezer or the like, and an electric expansion valve for a low-temperature fluid such as cold water.
The present invention relates to a stepping motor as a drive source of a control valve, and particularly to a waterproof structure of an electromagnetic coil.

[0002]

2. Description of the Related Art Generally, in an electric refrigerator or the like using a refrigeration cycle, an electromagnetic needle valve or an electric rotation control valve is used for controlling the flow rate of refrigerant.

[0003] In this case, the electromagnetic needle valve and the electric rotary control valve are often disposed in a high humidity environment. Therefore, the electromagnetic coil as a driving source of the electromagnetic needle valve and the electric rotary control valve is often used. In Japanese Patent Application Laid-Open No. H11-163, a waterproofing treatment is performed by a sealing process using a resin as a molding material, and means for suppressing a decrease in electrical performance is taken.

An example thereof will be described with reference to FIGS. 6 to 8. In FIG. 6, a valve body 31 is provided with a first joint 32 and a second joint 33 orthogonal to the first joint. The first joint 32 is provided with a primary port 32a, and the second joint 33 is provided with a secondary port 33a.
A valve chamber 34 is formed to connect a with the secondary port 33a.

[0005] A lower lid 35 having an opening at the top is fixed to the upper part of the valve body 31. A case 36 which is hermetically fixed to an upper opening of the lower lid 35 and forms a space in which a rotating portion of a stepping motor described later can be housed.
, A magnet 37 and a rotor 38 integrated with the magnet 37 are rotatably disposed. Furthermore, Case 3
An electromagnetic coil 39 is provided so as to be in contact with the outer periphery of 6. The magnet 37 rotatably provided inside the case 36 is divided and magnetized.

A female screw tube 40 is fixed to the inner periphery of the magnet 37. A valve stem 41 is fixed to the upper portion of the female screw tube 40, and a female screw 40 a is provided inside the female screw tube 40. A male screw 31 a screwed into the female screw 40 a is provided at the upper part of the valve body 31, and a needle valve 42 is provided at a lower end of the valve rod 41 and faces the valve seat 43.

A mandrel 45 is attached to the inside of the top of the case 36 downward.
A spiral guide ring 46 is wound around the mandrel 45, and a slider 47 is rotatably and vertically engaged with the spiral guide ring 46. The outer end of the slider 47 is engaged with a locking pin 48 erected on the rotor 38.

In the above configuration, when the electromagnetic coil 39 is energized, the rotor 38 rotates, and the slider 47 moves up and down along the spiral guide ring 46 in accordance with the rotation of the rotor 38, and the male screw 31a is fixed. The valve rod 41, that is, the needle valve 42, moves up and down to control the flow rate of the refrigerant.

The electromagnetic coil 39 is composed of a first electromagnetic coil 51 and a second electromagnetic coil 61 disposed in the vertical direction, and bobbins 50 and 60 around which the electromagnetic coils 51 and 61 are wound.

Reference numeral 20 denotes a stator, and this stator 20 is, as shown in FIG.
1, first middle stator member 22, second middle stator member 23
And the lower stator member 24. A plurality of downward comb teeth (magnetic pole teeth, the same applies hereinafter) 21a are formed on the upper stator member 21, and a plurality of upward comb teeth 22a are formed on the first middle stator member 22. A plurality of downward comb teeth portions 23a are formed on the stator member 23, and a plurality of upward comb teeth portions 24a are formed on the lower stator member 24.

As shown in FIG. 6 and FIG.
Is formed in an annular shape so that the bobbins 50 and 60 can be housed inside. The conventional bobbin 50, 60 and the stator 20 are formed by using a molding material 66 such as nylon resin or PBT resin to form an insertion hole for the magnet 38 at the center thereof (an insert metal fitting). )
Is collectively sealed by insert molding or injection molding. The connector of the lead wire 70 is filled with a potting material 72. Reference numeral 71 indicates a connector.

As described above, conventionally, the entire fixed side member (of the stepping motor) such as two bobbins wound with an electromagnetic coil and a stator is provided with an insert fitting for forming an insertion hole for the magnet 38 at the center. A structure in which the electromagnetic coil is drip-proof and waterproof, and the lead portion 71 of the lead wire 70 is sealed with a potting material by collectively sealing and molding with a molding material 66 such as nylon resin or PBT resin. It has become.

[0013]

As described above, in the conventional waterproof coil structure for a stepping motor, the sealing of the single electromagnetic coil is performed by welding when the edge of the bobbin is sealed with resin. However, the entire fixed side member is insert-molded.

By the way, at the time of insert molding, the insert metal is heated, so that the insert metal expands thermally. On the other hand, before the end of insert molding, the temperature of the insert metal decreases and thermal shrinkage occurs.In insert molding, thermal expansion and thermal shrinkage have a large effect, resulting in incomplete sealing with the mold material. Could be
In addition, the terminal portion has another problem that it is difficult to form a sufficiently dimensionally welded shape. Also, there is a disadvantage that the resin to be molded is deprived of heat by the insert fitting during the injection filling process, making it difficult to perform uniform molding. Furthermore, when used in a refrigeration circuit or the like, a stress is generated due to a difference in thermal expansion coefficient between the insert metal and the resin due to a temperature change, and this repetition may lead to a crack or breakage of the coil.

The present invention has been made to solve these problems, and comprises a set of electromagnetic coils arranged vertically,
In the stepping motor including the two bobbins around which each electromagnetic coil is wound and the stator, the bobbin, the upper electromagnetic coil including the connection terminal, and the lower electromagnetic coil are individually molded with a synthetic resin material. By superimposing the two molded coils and combining them with the stator to form the stator part of the stepping motor, insert molding is eliminated in the resin molding of the electromagnetic coil and An object of the present invention is to provide a waterproof structure of an electromagnetic coil for a stepping motor, which can be improved.

[0016]

According to the present invention, there is provided an upper electromagnetic coil section comprising a first bobbin, a coil wound on the bobbin, and a first terminal for connecting the coil to a lead wire.
A lower electromagnetic coil part comprising a second bobbin, a coil wound on the bobbin, and a second terminal for connecting the coil to a lead wire, the lower electromagnetic coil part being disposed closely below the upper electromagnetic coil part; In the electromagnetic coil for a stepping motor, the upper electromagnetic coil portion and the lower electromagnetic coil portion are individually molded with synthetic resin to form the upper electromagnetic coil structure and the lower electromagnetic coil structure, respectively. By doing so, the resin sealing molding of the electromagnetic coil can be performed without using the insert molding using the stator as an insert, which is a means for solving the problem.
As a result, according to the present invention, it is possible to reduce the stress due to the thermal expansion and contraction associated with the insert molding, and it is possible to improve the sealing moldability of the upper and lower electromagnetic coil structures.

[0017]

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

(Configuration) In FIG. 1, the upper electromagnetic coil structure 1 is connected to a first bobbin 3, a first electromagnetic coil 4 wound around the bobbin 3, and the external coil 30 with the coil 4 connected thereto. Terminal 2 (in this embodiment, terminal 2
Is attached to the bobbin 3), and the outside thereof is a first mold material (synthetic resin material).
5 and molded in a watertight seal and integrated. Reference numeral 5a denotes a terminal sealing portion of the molding material 5 which is formed to project to seal the lead portion of the terminal 2.

Further, as shown in FIG. 3, a box-shaped first filling space for filling the potting material 7 around the terminal portion to abut on a projection 16 to be described later to seal the portion. A projection 6 forming 7A is provided.

In FIG. 1, the lower electromagnetic coil structure 11
Has a vertically symmetric structure with the upper electromagnetic coil structure 1. Therefore, like the upper electromagnetic coil structure 1, the lower electromagnetic coil structure 11 includes the second bobbin 13,
A second electromagnetic coil 14 wound around the bobbin 13 and a second terminal 12 (see FIG. 2) for connecting the coil 14 to an external lead wire 30 are provided. It is molded with a second mold material (synthetic resin material) 15, watertightly sealed, integrated, and formed. Reference numeral 15a denotes a terminal sealing portion of the molding material 15 which is formed to project to seal the lead portion of the terminal 12. The protrusion 16 is provided on the second bobbin 13. In addition, each member of the lower electromagnetic coil structure 11 has a reference numeral “10” for each member of the upper electromagnetic coil structure 1.
Are added, and each member is marked with “second” to clarify the correspondence.

The stator 20 is formed of four parts, an upper stator member 21, a first middle stator member 22, a second middle stator member 23, and a lower stator member 24, as shown in FIG. I have. Then, the upper stator member 21
Has a plurality of downward comb teeth (magnetic pole teeth, the same applies hereinafter) 21a
Are formed, a plurality of upward comb teeth 22a are formed on the first middle stator member 22, a plurality of downward comb teeth 23a are formed on the second middle stator member 23, and the lower stator member 24 is formed on the lower stator member 24. A plurality of upward comb teeth 24a are formed.

An upper stator member 21 and a first middle stator member 22 are respectively fitted to the upper electromagnetic coil structure 1 from above and below, and a second middle stator member 23 and a lower stator member are fitted to the lower electromagnetic coil structure 11. The members 24 are respectively fitted from above and below. Next, the lower electromagnetic coil structure 11 and the upper electromagnetic coil structure 1 are overlapped so that the first middle stator member 22 and the second middle stator member 23 face each other.

By integrating the lower electromagnetic coil structure 11 and the upper electromagnetic coil structure 1 by superimposing them, the projections 6 of the first bobbin 3 and the projections 16 of the second bobbin 13 come into contact with each other and the projections 16 A first filling space 7 </ b> A of the box-shaped potting material 7 is formed between the first bobbin 3 and the outer edge protrusion 3 a of the first bobbin 3. Reference numeral 31 denotes a bracket.

The terminal cover 46a has its flange portion supported by the upper stator member 21 and the like, and has inner (left side in FIG. 4) inner peripheral surfaces having terminal sealing portions 5a and 15a.
Liquid-tight abutment. Further, the inside forms a connection space between the first and second terminals 2 and 12 and the lead wire 30, and the connection space functions as a second filling space 7 </ b> B of the potting material 7. Reference numeral 7C indicates a communication hole that connects the filling spaces 7A and 7B. The filling space 7B is located on the outer side (the right side in FIG. 4).
7D is formed on the open surface, and the potting material 7 is supplied from the outer surface 7D.

The filling spaces 7A and 7B of the potting material 7 thus formed are filled with the potting material 7 from the outer side (left side in FIG. 4) 7D (open side). , The terminals 2 and 12, the lead wire 30, and the terminals of the coils 4 and 14 can be sealed with the potting material 7, respectively. At the same time, the upper electromagnetic coil structure 1 and the lower electromagnetic coil structure 11 are bonded and integrated by the potting material 7 filled in the filling spaces 7A and 7B. The potting material 7 is preferably a thermosetting resin such as urethane resin which has waterproofness and flexibility. Due to the flexibility of the potting material 7, the difference in thermal expansion between components is absorbed,
Thereby, separation between components can be prevented.

(Operation / Effect) As described above, in this embodiment, the first bobbin 3 and the first bobbin 3
An upper electromagnetic coil portion composed of an electromagnetic coil 4 and a first terminal 2 for connecting the coil to a lead wire 30; a second bobbin 13 and a second bobbin wound around the bobbin 13;
A stepping device comprising an electromagnetic coil and a second terminal 12 for connecting the coil to a lead wire 30 and having a lower electromagnetic coil portion disposed below and in close contact with the upper electromagnetic coil portion; In the motor, the upper electromagnetic coil portion and the lower electromagnetic coil portion are individually molded with a synthetic resin material to form the upper electromagnetic coil structure 1 and the lower electromagnetic coil structure 11, respectively. Waterproofing can be performed without using "insert molding" with the stator as the insert,
As a result, it is possible to reduce the stress due to thermal expansion and contraction associated with the insert molding, and it is possible to improve the encapsulation moldability of the upper electromagnetic coil structure 1 and the lower electromagnetic coil structure 11.

Further, the upper electromagnetic coil structure 1, the lower electromagnetic coil structure 11, the stator 20, and the terminal cover 46a can be formed independently, that is, each member can be formed independently. Therefore, there is no restriction between the members, and the thermal shock resistance of each electromagnetic coil structure is improved in combination with the fact that the stress due to thermal expansion and contraction can be reduced, and as a result, each electromagnetic coil structure Has increased water resistance and reliability.

Further, since the encapsulation moldability of each electromagnetic coil structure is good, the setting range of molding conditions is widened, and stability and reliability are also enhanced.

Further, since the stress generated in each of the electromagnetic coil structures is small, it is possible to obtain a waterproof structure of the electromagnetic coil for a stepping motor which can be reduced in wall thickness and can save resources and reduce costs.

The potting material 7 acts to seal the terminals 2 and 12, the lead wire 30 and the terminals of the electromagnetic coils 4 and 14, respectively, and the upper electromagnetic coil structure 1 and the lower electromagnetic coil structure 11. To perform the function of adhesively bonding
Although the upper electromagnetic coil structure 1 and the lower electromagnetic coil structure 11 are separately molded, an adhesive material and an adhesive work for bonding the two electromagnetic coils are not required, which is advantageous in cost. It is.

[0031]

As described above, according to the present invention, the following effects can be obtained. (1) In a stepping motor including an upper electromagnetic coil portion and a lower electromagnetic coil portion disposed closely below the upper electromagnetic coil portion, the upper electromagnetic coil portion and the lower electromagnetic coil portion are individually molded with a synthetic resin material. Since the upper electromagnetic coil structure and the lower electromagnetic coil structure are formed in this manner, waterproof processing of the electromagnetic coil portion can be performed without using insert molding. As a result, it is possible to eliminate the influence of thermal expansion and thermal shrinkage due to insert molding, and it is possible to improve the sealing moldability of the upper electromagnetic coil structure and the lower electromagnetic coil structure. (2) Since the upper electromagnetic coil structure, the lower electromagnetic coil structure, the stator, and the terminal cover can be formed individually, that is, each member can be formed independently, there is no restriction between these members, Combined with reducing the stress due to expansion and contraction, the thermal shock resistance of each electromagnetic coil structure is improved, and as a result, the water resistance and reliability of each electromagnetic coil structure are increased. (3) Since the sealing moldability of each electromagnetic coil structure is good, the setting range of molding conditions is widened, and stability and reliability are also enhanced. (4) Since the stress generated in each electromagnetic coil structure is small, the wall thickness can be reduced, and resource saving and cost reduction can be achieved. (5) Since the potting material performs the function of sealing and sealing the terminal, the lead wire, and the terminal part of the electromagnetic coil, and the function of adhesively bonding the upper electromagnetic coil structure and the lower electromagnetic coil structure, Although the electromagnetic coil structure and the lower electromagnetic coil structure are separately molded, the adhesive and the bonding work for bonding the two electromagnetic coil structures are unnecessary, which is advantageous in cost. is there.

[Brief description of the drawings]

FIG. 1 is a sectional view of a waterproof structure of an electromagnetic coil for a stepping motor according to an embodiment of the present invention.

FIG. 2 is a view taken in the direction of arrow A in FIG. 1;

FIG. 3 is a partially enlarged sectional view of a waterproof structure of the electromagnetic coil for a stepping motor according to the embodiment of FIG. 1;

FIG. 4 is an assembled sectional view of a waterproof structure of the electromagnetic coil for a stepping motor according to the embodiment of FIG. 1;

FIG. 5 is a view taken in the direction of arrow B in FIG. 4;

FIG. 6 is a sectional view of a conventional electromagnetic control valve using a stepping motor.

FIG. 7 is an exploded perspective view of a stator of the stepping motor.

FIG. 8 is a sectional view of an electromagnetic coil portion of the stepping motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper electromagnetic coil structure 2 1st terminal 3 1st bobbin 4 1st electromagnetic coil 5, 15 Mold material 5a, 15a Terminal sealing part 6, 16 Projection 7 Potting material 7A 1st potting material filling space 7B 2nd potting material Filling space 7C Communication hole 7D Open surface (opening) 11 Lower electromagnetic coil structure 12 Second terminal 13 Second bobbin 14 Second electromagnetic coil 20 Stator 21 Upper stator member 22 First middle stator member 23 Second middle stator member 24 Lower stator member 30 Lead wire 46a Terminal cover

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3H062 AA02 BB21 CC02 EE06 HH08 5H002 AA06 AA07 AB06 AE07 AE08 5H604 BB02 BB14 CC01 CC05 CC11 CC19 DA13 DB01 PB04 PC01 PC03 PD02 PE01 QB12 5H605 AA02 AA17 BB05 CC17 EA15 EA29 EB38 GG18

Claims (6)

[Claims] 1. A first bobbin and a first bobbin wound on the bobbin.
An upper electromagnetic coil portion including an electromagnetic coil and a first terminal for connecting the electromagnetic coil to a lead wire, a second bobbin, a second electromagnetic coil wound around the bobbin, and connecting the electromagnetic coil to the lead wire And a lower terminal, comprising a lower terminal and a lower electromagnetic coil disposed closely below the upper electromagnetic coil, wherein the upper electromagnetic coil and the lower electromagnetic coil are And a waterproof structure for an electromagnetic coil for a stepping motor, wherein the upper electromagnetic coil structure and the lower electromagnetic coil structure are individually molded with a resin material. 2. The method according to claim 1, wherein the upper electromagnetic coil structure and the lower electromagnetic coil structure are individually molded with a synthetic resin while leaving a space for filling a potting material around each of the terminals. The waterproof structure of the electromagnetic coil for the stepping motor described in the above. 3. The filling of the potting material formed on each of the upper electromagnetic coil structure and the lower electromagnetic coil structure when the upper electromagnetic coil structure and the lower electromagnetic coil structure are superimposed. The waterproof structure for an electromagnetic coil for a stepping motor according to claim 2, wherein a box-shaped first potting material reservoir is formed by the space for use. 4. A method according to claim 1, wherein said first electromagnetic coil structure and said lower electromagnetic coil structure are molded from a synthetic resin.
While the middle stator member and the second middle stator member are sandwiched, the upper stator member and the lower stator member are respectively fitted to the outer sides of the upper electromagnetic coil structure and the lower electromagnetic coil structure. The waterproof structure for an electromagnetic coil for a stepping motor according to any one of claims 1 to 3, wherein the waterproof structure is provided. 5. A terminal sealing portion for sealing a lead portion of each of the first and second terminals is formed on each of the molded portions of the upper electromagnetic coil structure and the lower electromagnetic coil structure. A box-shaped terminal cover is provided so that the inner surfaces of the upper and lower electromagnetic coil structures are in liquid-tight contact with the respective terminal sealing portions in a state where the lower and upper electromagnetic coil structures are superimposed. The inside of the terminal cover forms a connection space between the first terminal and the second terminal and the lead wire,
The waterproof structure for an electromagnetic coil for a stepping motor according to any one of claims 1 to 4, wherein the connection space forms a second filling space of the potting material. 6. A waterproof structure for an electromagnetic coil for a stepping motor according to claim 5, wherein an opening as an inlet for said potting material is formed on one side surface of said box-shaped terminal cover.