Patent Description:
An automotive air conditioner typically includes a compressor, a condenser, an expander, an evaporator, and so forth arranged in a refrigeration cycle. For the expander, a motor operated expansion valve that enables accurate control of the valve opening degree by means of a stepping motor as a drive unit has been increasingly used. Such a motor operated expansion valve includes a mechanism for causing a valve element supported by an end of a shaft to touch and leave a valve seat formed on a body. For the movement of touching and leaving the valve seat, a technology of converting rotational movement of a rotor into translational movement of the shaft by employing a feed screw mechanism has been proposed.

Motor operated expansion valves with circuit boards have recently been increasingly used. In a case where a circuit board is mounted on a motor operated expansion valve, the circuit board needs to be isolated from external air in terms of corrosion protection of the circuit board. Thus, a technique of performing molding on a stator a plurality of times, and enclosing a circuit board by the molded resin obtained by the molding and a cap member formed by a separate process is known (refer to <CIT>, for example).

According to the motor operated expansion valve described in <CIT>, molding is performed twice on the stator. In this case, however, a molded resin is obtained by second molding performed on a molded resin obtained by first molding, and it is difficult to achieve airtightness between the two molded resins (a resin contact portion). In the motor operated expansion valve of <CIT>, the resin contact portion extends from outside the motor operated expansion valve to a space in which the circuit board is contained. Thus, with the structure of the motor operated expansion valve of <CIT>, entry of external air into the space containing the circuit board cannot be completely prevented. Such a problem is not limited to motor operated expansion valves but may be similarly present in various motor operated valves used for various applications.

The documents <CIT>, <CIT> and <CIT> disclose a motor operated valve comprising a stator unit, a rotor for driving a valve element and a can containing the rotor.

The present invention has been made in view of the above, and one object thereof is to provide a motor operated valve that achieves waterproof property of a space containing a circuit board.

The invention is a motor operated valve as defined in claim <NUM>.

According to the invention, a seal portion is provided between one open end portion of the cylindrical case containing the circuit board therein and the cap member, and a seal portion is provided between the other open end portion of the case and the body. This prevents entry of external air into a space in the case. Specifically, this prevents entry of moisture into the space containing the circuit board.

An embodiment of the invention will now be described. The description is not intended to limit the scope of the present invention, but to exemplify the invention.

The embodiment of the present invention will now be described in detail with reference to the drawings. In the description below, for convenience of description, the positional relationship in each structure may be expressed with reference to how the structure is depicted in the drawings. In the following embodiment and modifications thereof, components that are substantially the same will be designated by the same reference numerals and redundant description thereof may be omitted as appropriate.

<FIG> is a cross-sectional view illustrating a structure of a motor operated valve unit U according to the embodiment. The motor operated valve unit U includes a motor operated valve <NUM> and a piping body <NUM>. The motor operated valve <NUM> is applied to a refrigeration cycle of an automotive air conditioner, which is not illustrated. The refrigeration cycle includes a compressor for compressing a circulating refrigerant, a condenser for condensing the compressed refrigerant, an expansion valve for throttling and expanding the condensed refrigerant and delivering the resulting spray of refrigerant, and an evaporator for evaporating the spray of refrigerant to cool the air in a vehicle interior using the evaporative latent heat. The motor operated valve <NUM> functions as the expansion valve in the refrigeration cycle.

The motor operated valve <NUM> includes a valve unit <NUM>, and a motor unit <NUM> mounted thereon. The valve unit <NUM> includes a body <NUM> containing a valve section <NUM>. The body <NUM> functions as a "valve body". The body <NUM> includes a cylindrical first body <NUM> and a cylindrical second body <NUM>, which are coaxially mounted.

The first body <NUM> has a stepped cylindrical shape whose outer diameter decreases downward in a stepwise manner. The first body <NUM> has a recessed fitting portion <NUM> having a circular hole shape in a lower part thereof. The second body <NUM> has a bottomed cylindrical shape. An upper part of the second body <NUM> is press-fitted in the recessed fitting portion <NUM>. A valve hole <NUM> is formed to pass through the bottom portion of the second body <NUM> in the axial direction, and a valve seat <NUM> is formed at an upper end opening portion of the valve hole <NUM>. An inflow port <NUM> is formed at the lateral side of the second body <NUM>, and an outflow port <NUM> is formed at the bottom thereof. A valve chamber <NUM> is formed inside the first body <NUM> and the second body <NUM>. The inflow port <NUM> and the outflow port <NUM> communicate with each other via the valve chamber <NUM>.

An inlet port <NUM> and an outlet port <NUM> are formed at the lateral side of the piping body <NUM>. The inlet port <NUM> is connected with a pipe extending from the condenser side, and the outlet port <NUM> is connected with a pipe leading to an inlet of the evaporator. The inlet port <NUM> communicates with the inflow port <NUM>, and the outlet port <NUM> communicates with the outflow port <NUM>. The inlet port <NUM> and the outlet port <NUM> communicates with each other via a passage <NUM> formed in the piping body <NUM>.

Annular sealing members <NUM> and <NUM> are provided between the first body <NUM> and the piping body <NUM> and between the second body <NUM> and the piping body <NUM>, respectively. This structure prevents leakage of fluid through a clearance between the first body <NUM> and the piping body <NUM> and a clearance between the second body <NUM> and the piping body <NUM>.

<FIG> is a cross sectional view of the motor operated valve <NUM>.

A guiding member <NUM> is mounted vertically at the center of an upper part of the first body <NUM>. The guiding member <NUM> is a component made of a metal material by cutting, and has an external thread portion <NUM> formed on the outer surface of a middle portion in the axial direction of the guiding member <NUM>. A lower end portion of the guiding member <NUM> has a large diameter, and this large-diameter portion <NUM> is fixed coaxially to the center of an upper part of the first body <NUM>. A shaft <NUM> extending from a rotor <NUM> of the motor unit <NUM> is inserted in the inner side of the second body <NUM>. A lower end portion of the shaft <NUM> also serves as a valve element <NUM> of the valve section <NUM>. The valve element <NUM> moves toward and away from the valve seat <NUM> to adjust the opening degree of the valve section <NUM>. The guiding member <NUM> slidably supports the shaft <NUM> in the axial direction by the inner surface thereof, and rotatably and slidably supports a rotation shaft <NUM> of the rotor <NUM> by the outer surface thereof.

In the valve chamber <NUM>, an E-ring <NUM> is fitted to a lower portion of the shaft <NUM>. A spring support <NUM> is provided at an upper position of the E-ring <NUM>. A spring support <NUM> is also provided under the guiding member <NUM>. A spring <NUM> that biases the valve element <NUM> in the closing direction of the valve section <NUM> is inserted between the two spring supports <NUM> and <NUM> coaxially with the valve element <NUM>. In the present embodiment, because the lower end portion of the shaft <NUM> serves as the valve element <NUM>, the spring <NUM> also biases the shaft <NUM> in the valve closing direction.

Next, a structure of the motor unit <NUM> will be described.

The motor unit <NUM> is a three-phase stepping motor including the rotor <NUM> and a stator <NUM>. The motor unit <NUM> includes a can <NUM> having a bottomed cylindrical shape. The rotor <NUM> is located inside the can <NUM>, and the stator <NUM> is located outside of the can <NUM>. The can <NUM> is a bottomed-cylindrical member covering a space in which the valve element <NUM> and a mechanism for driving the valve element <NUM> are disposed and containing the rotor <NUM>, and defines an internal pressure acting space (internal space) in which the pressure of the refrigerant acts and an external non pressure acting space (external space) in which the pressure of the refrigerant does not act. The can <NUM> has an open end portion <NUM> fixed to the first body <NUM>.

The stator <NUM> includes a laminated core <NUM> and a bobbin <NUM>. The laminated core <NUM> is constituted by disc-shaped cores stacked in the axial direction. A coil <NUM> is wound around the bobbin <NUM>. The coil <NUM> and the bobbin <NUM> around which the coil <NUM> is wound constitute a "coil unit <NUM>". The coil unit <NUM> is mounted on the laminated core <NUM>.

The stator <NUM> is integrated with a cylindrical case <NUM> of the motor unit <NUM>. The case <NUM> is formed by injection molding of a corrosion-resistant resin (plastic) material. The stator <NUM> is coated with molding resin by the injection molding (also called "insert molding" or "molding"). The case <NUM> is constituted by the molding resin.

A cap member <NUM> is fitted into an upper end opening of the case <NUM> in such a manner that a projection on a lower face of the cap member <NUM> is inserted in the upper end opening of the case <NUM>. A circuit board <NUM> is mounted in a space S surrounded by the case <NUM> and the cap member <NUM>. The coil <NUM> is connected with the circuit board <NUM>. The case <NUM> includes a connector part <NUM>. Specifically, the connector part <NUM> is formed of the molding resin integrally with the case <NUM>. The connector part <NUM> integrally includes and protects therein a power supply terminal <NUM> for supplying power from an external power supply to the circuit board <NUM>. Hereinafter, the stator <NUM>, the case <NUM>, the circuit board <NUM>, the power supply terminal <NUM>, the connector part <NUM>, and the cap member <NUM> constitute a "stator unit <NUM>".

The rotor <NUM> includes a cylindrical rotor core <NUM>, and a magnet <NUM> around the outer circumference of the rotor core <NUM>. The rotor core <NUM> is mounted on the rotation shaft <NUM>. The magnet <NUM> is magnetized with a plurality of poles in the circumferential direction.

The rotation shaft <NUM> is made of a metal material by cutting. The rotation shaft <NUM> is produced by integrally forming the metal material into a bottomed cylindrical shape. The rotation shaft <NUM> is mounted (outserted) around the guiding member <NUM> with its open end facing downward. An internal thread portion <NUM> formed on the inner surface of the rotation shaft <NUM> engages with the external thread portion <NUM> of the guiding member <NUM>. A feed screw mechanism constituted by the thread portions converts the rotational movement of the rotor <NUM> into the translational movement in the axial direction. The engagement of the internal thread portion <NUM> and the external thread portion <NUM> of the feed screw mechanism will be referred to as a "screwed portion".

An upper portion of the shaft <NUM> is reduced in diameter, and this diameter-reduced portion extends through the bottom of the rotation shaft <NUM>. An annular stopper <NUM> is fixed to the leading end of the diameter-reduced portion. A back spring <NUM> that biases the shaft <NUM> downward (valve closing direction) is provided between the base end of the diameter-reduced portion and the bottom of the rotation shaft <NUM>. With this structure, while the valve section <NUM> is being opened, the shaft <NUM> is moved integrally with the rotor <NUM> in a state in which the stopper <NUM> is stopped by the bottom of the rotation shaft <NUM>. In contrast, while the valve section <NUM> is being closed, the back spring <NUM> is compressed by reaction force that the valve element <NUM> receives from the valve seat <NUM>. In this process, elastic reaction force of the back spring <NUM> presses the valve element <NUM> against valve seat <NUM>, which increases the seating performance (valve closing performance) of the valve element <NUM>.

An annular sealing member <NUM> is provided between the first body <NUM> and the case <NUM>. This structure prevents entry of external air (such as moisture) through a clearance between the first body <NUM> and the case <NUM>.

<FIG> is a cross-sectional view of a structure of the stator unit <NUM>.

As described above with reference to <FIG>, the case <NUM> and the cap member <NUM> forms the space S. The circuit board <NUM> is included in the space S.

A leak hole <NUM> through which the inside of the connector part <NUM> and the space S communicate with each other is formed in the case <NUM>. Details of the leak hole <NUM> will be described later.

<FIG> illustrate details of a fitting structure of the case <NUM> and the cap member <NUM>. <FIG> is a cross-sectional view taken along arrows A-A in <FIG>, and <FIG> is an exploded view of the fitting of the case <NUM> and the cap member <NUM> in <FIG>.

In the present embodiment, an open end portion <NUM> of the case <NUM> and the cap member <NUM> are fitted annularly in such a manner that a projection on the lower face of the cap member <NUM> is inserted in the upper end opening of the case <NUM>. Thus, the upper face of the open end portion <NUM> and the lower face of the cap member <NUM> form an annular contact surface therebetween. The annular contact surface is irradiated with laser, so that the case <NUM> and the cap member <NUM> are welded together. Details of the fitting structure of the case <NUM> and the cap member <NUM> will be described below.

As illustrated in <FIG>, the case <NUM> has the open end portion <NUM> and two positioning projections <NUM> (which function as "positioning members"). The open end portion <NUM> is a cylindrical part at the upper part of the case <NUM>. The positioning projections <NUM> for positioning the circuit board <NUM> with respect to the case <NUM> are on the inner side of the open end portion <NUM>.

As illustrated in <FIG>, the cap member <NUM> has a contact portion <NUM> having the contact surface, a projection <NUM> having a rectangular cross section, and recessed portions <NUM>. The contact portion <NUM> is over the entire circumferential edge of the bottom face of the cap member <NUM>. The projection <NUM> is formed annularly along the inner side of the contact portion <NUM> on the bottom surface of the cap member <NUM>. Two recessed portions <NUM> are formed on the inner side of the projection <NUM> on the bottom face of the cap member <NUM>.

The contact portion <NUM> is in contact with an end face <NUM> (the upper face at the open end portion <NUM>) of the case <NUM>. The projection <NUM> has an outer circumferential face facing the inner circumferential face of the open end portion <NUM>. The projection <NUM> and the open end portion <NUM> form a fitting portion <NUM> (<FIG>).

As illustrated in <FIG>, the circuit board <NUM> is accommodated in the space S formed by the case <NUM> and the cap member <NUM>. The circuit board <NUM> has two positioning holes <NUM>. The two positioning projections <NUM> are inserted in the two positioning holes <NUM>, so that the circuit board <NUM> is positioned with respect to the case <NUM>. In addition, the two positioning projections <NUM> are also fitted into the two recessed portions <NUM> of the cap member <NUM>. This structure enables the cap member <NUM> to be positioned with respect to the case <NUM>. Thus, the positioning projections <NUM> have both of the functions of positioning the circuit board <NUM> with respect to the case <NUM> and positioning of the cap member <NUM> with respect to the case <NUM>.

The positioning projections <NUM> are press-fitted into and fixed to the recessed portions <NUM>. This positions the cap member <NUM> with respect to the case <NUM>, and keeps the spacing between the outer circumferential face of the projection <NUM> and the inner circumferential face of the case <NUM> (the gap of the fitting portion <NUM>) uniform over the entire circumference.

Next, the welding of the case <NUM> and the cap member <NUM> will be described.

<FIG> is an enlarged cross-sectional view of part X in <FIG>.

As described above, the fitting portion <NUM> is formed by the inner circumferential face of the case <NUM> and the projection <NUM> of the cap member <NUM>. The contact portion <NUM> of the cap member <NUM> is in contact with the end face <NUM> of the case <NUM>. The cap member <NUM> is made of a laser transparent resin material, and the case <NUM> is made of laser absorbing resin material. Laser emitted to the contact portion <NUM> from the cap member <NUM> side passes through the cap member <NUM> and is then absorbed by the end face <NUM> of the case <NUM>. Heat generated by the absorbed laser melts part of the end face <NUM> of the case <NUM>. As illustrated in <FIG>, the melted resin material R enters the gap of the fitting portion <NUM>, and solidifies in such a manner as to bridge between the outer circumferential face of the projection <NUM> of the cap member <NUM> and the open end portion <NUM> of the case <NUM>.

In the present embodiment, the melted resin material R is made to enter the gap of the fitting portion <NUM>, and solidify in such manner as to bridge between the outer circumferential face of the projection <NUM> of the cap member <NUM> and the open end portion <NUM> of the case <NUM>. As a result, the cap member <NUM> and the case <NUM> are also welded together at the fitting portion <NUM> in addition to the contact portion <NUM>, which improves the weldability. Hereinafter, the welded portion of the cap member <NUM> and the case <NUM> with the melted resin material R will be referred to as a "welded portion <NUM>" or a "first seal portion".

<FIG> are cross-sectional views illustrating mounting of the stator unit <NUM> onto the first body <NUM>. <FIG> illustrates a state during a mounting process, and <FIG> illustrates a state in which the mounting is completed.

Before the mounting, the circuit board <NUM> is placed in the case <NUM>. In addition, as explained with reference to <FIG>, the case <NUM> and the cap member <NUM> are welded together.

In the mounting, the can <NUM> is inserted in the stator unit <NUM> from an open end portion <NUM> of the case <NUM> opposite the open end portion <NUM>. The mounting of the stator unit <NUM> onto the first body <NUM> is then completed in a state in which the open end portion <NUM> contains the open end portion <NUM> of the can <NUM> and the sealing member <NUM>.

The open end portion <NUM>, which is one of the open end portions of the case <NUM>, is mounted on the first body <NUM> in such a state in which the sealing member <NUM> is in contact with the inner circumferential face of the open end portion <NUM>. In addition, the open end portion <NUM> is welded to the cap member <NUM> with the welded portion <NUM>. Thus, the case <NUM> is sealed from the outside at the two open end portions <NUM> and <NUM>. This structure prevents entry of air outside the case <NUM> into the space S located in the case <NUM>.

The connector part <NUM> has the leak hole <NUM>. Before mounting of the stator unit <NUM> onto the first body <NUM>, the case <NUM> and the cap member <NUM> are welded together. Thus, the gas pressure in the space S increases as the can <NUM> is inserted into the stator unit <NUM>. When this pressure becomes too high, the circuit board <NUM>, etc. accommodated in the space S may be damaged. In the present embodiment, the pressure in the space S leaks to the inside of the connector part <NUM> through the leak hole <NUM>. This structure prevents the circuit board <NUM>, etc. from being damaged when the can <NUM> is inserted in the stator unit <NUM> and the stator unit <NUM> is mounted on the first body <NUM>.

After the stator unit <NUM> is mounted on the first body <NUM>, the temperature in the space S changes during operation of the motor operated valve <NUM>. In a case where the leak hole <NUM> is not present and the case <NUM> is airtight, the pressure in the space S changes with the temperature change. As this pressure becomes higher, failures such as damage to the circuit board <NUM>, a fracture in the welded portion <NUM>, deformation of the case <NUM> or the cap member <NUM>, and damage to the coil <NUM> (see <FIG>). In contrast, the leak hole <NUM> formed so that the pressure in the space S leaks to the inside of the connector part <NUM> prevents damage to the circuit board <NUM> and the like during operation of the motor operated valve <NUM>.

The leakage of the pressure in the space S during operation of the motor operated valve <NUM> will be explained in more detail. The connector part <NUM> is connected with an external connector (not illustrated). A harness is connected with a terminal of the external connector. Thus, the pressure in the space S leaks to the outside via the leak hole <NUM> and the harness. In addition, a seal ring (not illustrated) is provided between the connector part <NUM> and the external connector. According to this structure, the leak hole <NUM> communicates with the inside of the harness, and is sealed from the air outside the motor operated valve <NUM>. Because the space S does not communicate with the outside of the motor operated valve <NUM>, entry of the external air into the space S is prevented even when the leak hole <NUM> is present.

As described above, according to the present embodiment, the case <NUM> is formed by the molding resin to contain the stator <NUM>. Thus, the case <NUM> is formed by one process of molding. In addition, the open end portion <NUM> of the cylindrical case <NUM> is welded to the cap member <NUM>, and the open end portion <NUM> thereof has the sealing member <NUM> (second seal portion) between the open end portion <NUM> and the first body <NUM>. The first seal portion and the second seal portion prevent entry of the air into the space S. This ensures the waterproof property of the space S containing the circuit board <NUM>.

According to the present embodiment, the connector part <NUM> is produced integrally with the case <NUM> by one molding process. This reduces the number of components of the motor operated valve <NUM>. As the number of components is smaller, the number of portions that need to be sealed between components can be reduced. Thus, entry of external air into the motor operated valve <NUM> is prevented.

<FIG> are cross-sectional views of motor operated valves according to modifications of the present embodiment. <FIG> illustrates a motor operated valve <NUM> according to a first modification, <FIG> illustrates a motor operated valve <NUM> according to a second modification, and <FIG> illustrates a motor operated valve <NUM> according to a third modification.

As illustrated in <FIG>, the motor operated valve <NUM> according to the first modification is different from the motor operated valve <NUM> according to the embodiment in the shape of a case <NUM>. The case <NUM> includes an inner molded part <NUM> and a cylindrical outer molded part <NUM>. The stator <NUM> is covered with the inner molded part <NUM> by molding. The inner molded part <NUM> made of molding resin is covered with the outer molded part <NUM> by molding. Thus, the outer molded part <NUM> is made of molding resin. The connector part <NUM> is formed integrally with the outer molded part <NUM>.

In the first modification as well, an open end portion <NUM> of the outer molded part <NUM> and the cap member <NUM> are welded to form a welded portion <NUM>. In addition, the sealing member <NUM> is provided between an open end portion <NUM> of the outer molded part <NUM> and the first body <NUM>. The inner molded part <NUM> is entirely contained in the outer molded part <NUM>. Thus, the inner molded part <NUM> is not exposed to the outside of the motor operated valve <NUM>. The sealing structures at the two open end portions <NUM> and <NUM> prevent entry of external air into the outer molded part <NUM>. In addition, a resin contact portion (between the outer molded part <NUM> and the inner molded part <NUM>) communicating with the space S is completely isolated from the outside of the motor operated valve <NUM>. Thus, in the first modification as well, entry of external air into the space S is prevented.

In the motor operated valve <NUM> according to the first modification as well, entry of external air into the space S is prevented, and the waterproof property of the space S is ensured. In terms of sealing property, however, the motor operated valve <NUM> according to the embodiment constituted by a smaller number of components is more preferable.

As illustrated in <FIG>, the motor operated valve <NUM> according to the second modification is different from the motor operated valve <NUM> according to the embodiment in the shape of a case <NUM>. The case <NUM> includes an inner molded part <NUM> and a cylindrical outer molded part <NUM>. The stator <NUM> is covered with the inner molded part <NUM> by molding. The outer molded part <NUM> is obtained by molding in a process different from that of the inner molded part <NUM>. Thus, the outer molded part <NUM> is made of molding resin. The connector part <NUM> is formed integrally with the outer molded part <NUM>.

The stator <NUM> covered with the inner molded part <NUM> and the circuit board <NUM> are accommodated in the outer molded part <NUM>. Thereafter, the cap member <NUM> is provided at the open end portion <NUM> of the outer molded part <NUM>, and the stator unit <NUM> is thus produced.

In the second modification as well, an open end portion <NUM> and the cap member <NUM> are welded to form a welded portion <NUM>. In addition, the sealing member <NUM> is provided between an open end portion <NUM> of the outer molded part <NUM> and the first body <NUM>. The inner molded part <NUM> is entirely contained in the outer molded part <NUM>. Thus, the inner molded part <NUM> is not exposed to the outside of the motor operated valve <NUM>. The sealing structures at the two open end portions <NUM> and <NUM> prevent entry of external air into the outer molded part <NUM>. In addition, the contact between the outer molded part <NUM> and the inner molded part <NUM> is completely isolated from the outside of the motor operated valve <NUM>. Thus, in the second modification as well, entry of external air into the space S is prevented.

In the motor operated valve <NUM>, the inner molded part <NUM> and the outer molded part <NUM> are formed by separate processes, and mounted in a process of mounting the case <NUM>. Thus, the dimensions of the inner molded part <NUM> and the outer molded part <NUM> need to be matched. In the case of the motor operated valve <NUM> of the first modification (see <FIG>), positioning of the inner molded part <NUM> and the outer molded part <NUM> can be readily performed by using a mold for molding of the outer molded part <NUM>. The motor operated valve <NUM> of the first modification is more preferable than the motor operated valve <NUM> of the second modification in that the stator <NUM> can be easily positioned relative to the case <NUM>.

As illustrated in <FIG>, the motor operated valve <NUM> according to the third modification is different from the motor operated valve <NUM> according to the embodiment in the shape of a case <NUM>. In the motor operated valve <NUM> of the third modification, the stator <NUM> is not covered with molding resin. The case <NUM> is obtained by molding in a manner similar to the outer molded part <NUM> (see <FIG>) in the second modification. The connector part <NUM> is formed integrally with the case <NUM>.

The case <NUM> accommodates the stator <NUM> and the circuit board <NUM> therein. Thereafter, the cap member <NUM> is mounted at an open end portion <NUM> of the case <NUM>, and the stator unit <NUM> is thus obtained.

In the third modification as well, the open end portion <NUM> and the cap member <NUM> are welded to form a welded portion <NUM>. In addition, the sealing member <NUM> is provided between an open end portion <NUM> of the case <NUM> and the first body <NUM>. The sealing structures at the two open end portions <NUM> and <NUM> prevent entry of external air into the case <NUM>. Thus, in the third modification as well, entry of external air into the space S is prevented.

Because the stator <NUM> is accommodated directly in the case <NUM>, the motor operated valve <NUM> can be more readily produced than the motor operated valve <NUM> (see <FIG>) and the motor operated valve <NUM> (see <FIG>) in which the stator <NUM> is covered with molding resin. Protection of the stator <NUM> (the coil <NUM> in <FIG>) by molding resin, however, facilitates heat dissipation from the coil <NUM>, and enables control of the resistance of the coil <NUM>. In this regard, the motor operated valve <NUM> and the motor operated valve <NUM> are more preferable than the motor operated valve <NUM>.

The embodiment of the present invention has been described above. The present invention is not limited to the embodiment and it will be obvious to those skilled in the art that various modifications could be further developed within the technical idea underlying the present invention without departing from the scope of protection defined in the independent claim <NUM>.

In the embodiment described above, welding is used for the first seal portion, and the seal ring is used for the second seal portion. In a modification, a seal ring may be used for the first seal portion. For example, a seal ring may be provided between a projection of the cap member and the inner circumferential face of the case.

In the embodiment described above, the structure in which the second seal portion is provided between the inner circumferential face of the case and the outer circumferential face of the first body has been explained. In a modification not belonging to the invention, a seal ring may be provided as the second seal portion between the inner circumferential face of the case and the outer circumferential face of the can. Note that a structure in which an open end portion of the can is located further inside the case than the second seal portion is implemented in the invention and has the advantage that the welded portion of the open end portion of the can and the body is not corroded by external air.

In the embodiment described above, the motor operated valve in which the valve element touches and leaves the valve seat and the valve section is completely closed in the valve closed state has been described. In a modification, a valve element may be moved into and out of a valve hole like a so-called spool valve, and a slight leakage of fluid may be permitted in the valve closed state.

While the motor operated valve is a motor operated expansion valve in the embodiment described above, the motor operated valve may be an on-off valve or a flow control valve without an expanding function.

In the embodiment described above, the structure in which the valve element and the shaft are integrally formed has been described. In a modification, the structure is not limited thereto, and the valve element and the shaft may be separate members that can move integrally. In this case, the valve element and the shaft may be structurally integrated. Alternatively, the valve element and the shaft may be integrally movable, and also movable relative to each other. For example, the valve element and the shaft may be integrally movable while the valve is being opened, and may be movable relative to each other during valve closing operation, like the motor operated valve described in <CIT>.

Claim 1:
A motor operated valve comprising:
a body (<NUM>);
a valve element (<NUM>) that is moved toward and away from a valve hole (<NUM>) formed in the body (<NUM>) to close and open a valve section (<NUM>);
a rotor (<NUM>) for driving the valve element (<NUM>) in opening/closing directions of the valve section (<NUM>);
a can (<NUM>) that is a bottomed cylindrical member fixed to the body (<NUM>) and containing the rotor (<NUM>), and that defines an internal space in which fluid pressure acts and an external space in which fluid pressure does not act; and
a stator unit (<NUM>) including a case (<NUM>, <NUM>, <NUM>, <NUM>) having a cylindrical shape and made of resin, a stator (<NUM>) mounted in the case (<NUM>, <NUM>, <NUM>, <NUM>) and coaxially around the can (<NUM>), a circuit board (<NUM>) mounted in the case (<NUM>, <NUM>, <NUM>, <NUM>), a power supply terminal (<NUM>) connected with the circuit board (<NUM>), a connector part (<NUM>) made of resin and integrally including the power supply terminal (<NUM>) therein, and a cap member (<NUM>), the cap member (<NUM>) and the case (<NUM>, <NUM>, <NUM>, <NUM>) forming a space (S) containing the circuit board (<NUM>), the can bottom being located in the space (S), wherein
the connector part (<NUM>) has a leak hole (<NUM>) that permits leakage of pressure in the space (S) containing the circuit board (<NUM>) to outside and wherein
the connector part (<NUM>) is formed integrally with the case (<NUM>, <NUM>, <NUM>, <NUM>) by molding resin,
a first seal portion (<NUM>, <NUM>, <NUM>, <NUM>) is provided between a first open end portion (<NUM>, <NUM>, <NUM>, <NUM>) of the case (<NUM>, <NUM>, <NUM>, <NUM>) and the cap member (<NUM>), and
a second seal portion (<NUM>) is provided between a second open end portion (<NUM>, <NUM>, <NUM>, <NUM>) of the case (<NUM>, <NUM>, <NUM>, <NUM>) and the body (<NUM>), the second seal portion (<NUM>) being a seal ring (<NUM>),
the seal ring (<NUM>) is between an inner circumferential face of the case (<NUM>, <NUM>, <NUM>, <NUM>) and an outer circumferential face of the body (<NUM>),
an open end portion of the can (<NUM>) is located further inside the case (<NUM>, <NUM>, <NUM>, <NUM>) than the seal ring (<NUM>),
a position of the can (<NUM>) fixed to the body (<NUM>) is farther from an open end of the second open end portion (<NUM>, <NUM>, <NUM>, <NUM>) of the case (<NUM>, <NUM>, <NUM>, <NUM>) in an axial direction than the seal ring (<NUM>).