JP7736738B2 - Electric valve and refrigeration cycle system - Google Patents

Description

The present invention relates to an electrically operated valve having sliding parts made of resin material and a refrigeration cycle system using the same.

In recent years, with the aim of improving environmental conservation and ease of maintenance, refrigeration cycle systems have been proposed that do not use refrigeration oil, i.e., operate in an oil-free state or with a low oil volume, as described in Patent Document 1, for example.

A typical motor-operated valve has a drive unit with a screw feed unit that converts rotary motion into linear motion, and a sliding unit that occurs between the valve element, which moves axially due to this linear motion, and a guide unit. This increases the sliding resistance of the drive unit (particularly the screw feed unit) and the sliding unit during rotation, potentially making smooth rotation difficult (hereinafter referred to as "conventional problem (increased sliding resistance)").

As shown in Figure 10, Patent Document 2 describes an electric valve (hereinafter referred to as a "conventional electric valve") 1000, which includes a valve body 1010, a valve element 1020, and a stepping motor 1030. The valve body 1010 has a valve port 1011a, a valve seat 1011b, and a cylindrical guide portion 1011c, and is connected to a first joint pipe 1001 and a second joint pipe 1002. The valve element 1020 also has a guide shaft portion 1020g that slidably engages with the inner periphery of the valve portion 1020a and the guide portion 1011c. The stepping motor 1030 also has a magnet rotor 1032 that rotates integrally with the valve element 1020.

Patent Document 2 describes a configuration in which the guide shaft portion 1020g is movable only in the rotational direction relative to the guide portion 1011c, thereby eliminating the need for a screw feed portion and reducing sliding resistance in the drive portion.

However, in Patent Document 2 (particularly, see the first example: paragraphs [0042], [0064]-[0065] and Figure 1), the guide portion 1011c and the guide shaft portion 1020g are made of metal. Therefore, when used in a refrigeration cycle system operated in an oil-free or low-oil state, the sliding resistance at the sliding portion is extremely high, which could result in galling or other problems. Also, in Patent Document 2 (particularly, see the fifth example: paragraphs [0064]-[0065] and Figure 14), the guide shaft portion 1020g is coated with a synthetic resin. However, because the guide portion 1011c is made of metal, significant wear of the coated synthetic resin can occur, potentially increasing the sliding resistance at the sliding portion. Therefore, Patent Document 2 (particularly, see the first and fifth examples) still fails to resolve the conventional problem (increased sliding resistance).

Japanese Patent Application Laid-Open No. 2021-162213 Japanese Patent Application Publication No. 8-312822

The object of the present invention is to provide an electrically operated valve and a refrigeration cycle system using the same that, by optimizing the materials that make up the sliding parts, enable smooth rotation even in an oil-free state or with a low oil volume, thereby improving the operability and durability of the sliding parts.

To solve the above problem, a valve body includes a valve element having a valve portion on one end thereof and a rotor that rotates integrally with the valve element; a flow path chamber that houses the valve portion, a valve seat that faces the valve portion radially, and a valve port that extends radially and is communicative with the flow path chamber; and a case that connects to the valve body and defines a back pressure chamber for the rotor portion. The valve body has a first port that directly communicates with the flow path chamber, a second port that communicates with the valve port, and a guide member that axially supports the valve element, which is disposed along the axis, and guides it circumferentially. The valve portion has a seal that closes the valve port and a flow path that is communicative with the valve port. The rotation of the rotor changes the state of communication between the valve port and the flow path, thereby controlling the flow rate of fluid flowing through the valve port. The valve element and the guide member mutually constitute sliding parts and are made of a resin material. This motor-operated valve.

Furthermore, in the above-mentioned motor-operated valve, the resin material may be PPS with PTFE added.

Furthermore, in the above-mentioned motor-operated valve, the resin material may be reinforced with glass fiber or carbon fiber.

The above-mentioned motor-operated valve may further include a radial support means for radially supporting the valve body, which is set at a predetermined radial gap between the valve body and the guide member, and which supports the valve body. The radial support means may have a one-end radial gap adjacent to the valve body and an other-end radial gap adjacent to the other end of the one-end radial gap, and the one-end radial gap may be set smaller than the other-end radial gap.

Furthermore, in the above-mentioned motor-operated valve, the valve element may have, in order from one end to the other end, a small-diameter guide shaft portion having the valve portion at one end thereof and a large-diameter guide shaft portion, and the guide member may have, in order from one end to the other end, a small-diameter guide portion and a large-diameter guide portion, and the one-end radial gap between the small-diameter guide shaft portion and the small-diameter guide portion may be set smaller than the other-end radial gap between the large-diameter guide shaft portion and the large-diameter guide portion.

The above-mentioned motor-operated valve may further include an axial support means for engaging the axially opposing surfaces of the valve element and the guide member, which are the sliding part, and supporting the valve element in the axial direction, wherein the first port communicates with the valve port via the flow path chamber, and the valve element extends along the axis and has a pressure equalizing hole that constantly communicates between the second port and the back pressure chamber.

Furthermore, in the above-mentioned motor-operated valve, the valve body may have an annular step at the boundary between the small-diameter guide shaft portion and the large-diameter guide shaft portion, and the guide member may have an annular step at the boundary between the small-diameter guide portion and the large-diameter guide portion, and the axial support means may engage the step of the valve body and the step of the guide member with each other.

The refrigeration cycle system may also include a compressor, a condenser, an expansion valve, and an evaporator, and the motor-operated valve may be used as the expansion valve.

This invention provides an electrically operated valve and a refrigeration cycle system using the same, which, by optimizing the materials that make up the sliding parts, allows for smooth rotation even in an oil-free state or with a low oil level, improving the operability and durability of the sliding parts.

1A and 1B are cross-sectional views of a motor-operated valve according to a first embodiment of the present invention in an open state, where FIG. 1A is a longitudinal cross-sectional view of the motor-operated valve, and FIG. 1B is an enlarged view of the Ib-Ib cross-section of FIG. 1A. 2A and 2B are cross-sectional views of the motor-operated valve shown in FIG. 1 in a valve-closed state, where FIG. 2A is a longitudinal cross-sectional view of the motor-operated valve, and FIG. 2B is an enlarged cross-sectional view of FIG. 2A taken along line IIb-IIb. 1A and 1B are explanatory diagrams of the first embodiment and a modified axial support means, in which (a) is an enlarged view of the area surrounded by dashed line IIIa shown in FIG. 2 in the first embodiment, (b) is an enlarged view of the area surrounded by dashed line IIIb shown in FIG. 2 in the first embodiment, (c) is an enlarged view corresponding to (a) in the modified axial support means, and (d) is an enlarged view corresponding to (b) in the modified axial support means. 2A and 2B are explanatory diagrams of flow path section variants 1 and 2 of the first embodiment, in which (a) is a cross-sectional view of flow path section variant 1 corresponding to FIG. 1B, (b) is a cross-sectional view of flow path section variant 1 corresponding to FIG. 2B, (c) is a cross-sectional view of flow path section variant 2 corresponding to (a), and (d) is a cross-sectional view of flow path section variant 2 corresponding to (b). FIG. 1B is an explanatory view (a cross-sectional view corresponding to FIG. 1A) of a modified second joint pipe of the first embodiment. 1A and 1B are explanatory views (cross-sectional views corresponding to FIG. 1A) of modified valve bodies of the first embodiment; 7A and 7B are cross-sectional views of a motor-operated valve according to a second embodiment of the present invention in an open state, in which (a) is a longitudinal cross-sectional view of the motor-operated valve, (b) is an enlarged cross-sectional view of VIIb-VIIb in (a), and (c) is an enlarged view of the area surrounded by the dashed line VIIc in (a). 8A and 8B are explanatory diagrams of a modified stopper portion of the second embodiment, in which (a) is a cross-sectional view of the main part corresponding to FIG. 7A, and (b) is a cross-sectional view taken along line VIIIb-VIIIb shown in (a). 1 is a diagram showing a refrigeration cycle system of the present invention. FIG. 1 is a longitudinal sectional view showing a motor-operated valve according to a conventional technique.

An embodiment of the present invention will be described in detail with reference to Figures 1 to 9. However, the present invention is not limited to this embodiment.

<Terminology>
In this specification and the claims, the terms "left,""right,""upper," and "lower" refer to the directions shown in Figures 1(a), 2(a), 3, 5-6, 7(a), (c), and 8(a). In this specification and the claims, the terms "one end" and "other end" refer to the "lower end" and "upper end" in the drawings. In this specification and the claims, the term "sliding portion" refers to the "area of the valve body and the guide member that are slidably engaged." In this specification and the claims, the term "cooling means" refers to the "means for cooling the sliding portion." In this specification and the claims, the term "surface pressure" refers to the "load per unit area on the contact surface." In this specification and the claims, the term "radial support means" refers to the "means for supporting the valve body in the radial direction." In this specification and the claims, the term "axial support means" refers to the "means for supporting the valve body in the axial direction."

(First embodiment)
<Configuration of the motor-operated valve>
1 and 2, a motor-operated valve 100a according to a first embodiment of the present invention will be described. The motor-operated valve 100a is mainly composed of a valve body 10A, a valve element 20, a stepping motor 30, and a support member 40. Each component of the motor-operated valve 100a will be described below in order.

Here, as will be described in detail later, the motor-operated valve 100a in the first embodiment employs the first measure (improving the material of the sliding parts) and constructs both sliding parts from resin material, thereby resolving the conventional problem (increased sliding resistance) and improving the operability and durability of the sliding parts.

The valve body 10A comprises a bowl-shaped member 10 that defines a portion of the flow channel chamber 13, a guide member 11 that has a roughly cylindrical shape extending along the axis L and is fixedly connected to the bottom side of the bowl-shaped member 10, and a bottom cover 12 that is annular and integrally molded with the guide member 11.

The first coupling pipe 1, which serves as a fluid path for a refrigerant or the like, is connected to the side of the bowl-shaped member 10, and the second coupling pipe 2 is connected to the bottom. The first coupling pipe 1 is directly connected to the flow path chamber 13 via the first port 1a. The second coupling pipe 2 is connected to the flow path chamber 13 via the second port 2a, the internal flow path 14 of the guide member 11, and the valve port 11a (details will be described later). The first coupling pipe 1 and the second coupling pipe 2 are made of materials such as copper or stainless steel, and are fixed to the bowl-shaped member 10 by brazing or the like.

The guide member 11 has an insertion hole that opens from one end to the other along the axis L. This insertion hole is provided with a large-diameter guide portion 11cb and a small-diameter guide portion 11ca, extending from the other end toward the one end. The small-diameter guide portion 11ca has a smaller inner diameter than the large-diameter guide portion 11cb, and an internal flow path 14 extending in the direction of the axis L is defined in the inner region of the one end. Furthermore, a flat, annular step portion 11e (axially opposing surface) is formed at the boundary between the large-diameter guide portion 11cb and the small-diameter guide portion 11ca. Furthermore, as shown in Figures 1(a) and 2(a), the guide member 11 is formed with a valve port 11a that is concentric with the first port 1a and is located on the opposite side of the axis L from the first coupling pipe 1 with respect to the axis L, and that penetrates radially between the internal flow path 14 and the flow path chamber 13, and an annular valve seat 11b (see Figures 1(b) and 2(b)) that is formed around this valve port 11a. In addition, a drawn-out portion 11g that extends radially outward is formed on part of the outer circumferential surface at the other end of the guide member 11.

The lower cover 12 has an inner peripheral portion that is joined to the guide member 11, and an outer peripheral portion that is joined to the other end of the bowl-shaped member 10 and one end of the case 31. The lower cover 12 is formed with a communication hole 12a that constantly connects the flow path chamber 13 and the back pressure chamber 16 and functions as a pressure equalization hole.

In the first embodiment, the shape of the valve port 11a when viewed from a direction perpendicular to the axis L is circular, but this is not limited to this and various shapes can be used, such as rectangular, elliptical, or any asymmetrical shape. Also, in the first embodiment, the bowl-shaped member 10 and the guide member 11 are separate bodies, but this is not limited to this and the bowl-shaped member 10 and the guide member 11 may be formed as a single unit, as in the conventional motor-operated valve shown in Figure 10.

The valve element 20 is a member extending along the axis L. One end of the valve element 20 is inserted into the insertion hole of the guide member 11. From one end to the other, a small-diameter guide shaft portion 20g and a large-diameter guide shaft portion 20h, each having a valve portion 20a at one end, are formed with successively increasing diameters in a stepped manner. A flat, annular one-end step portion 20i (step portion, axially opposing surface) is formed at the boundary between the small-diameter guide shaft portion 20g and the large-diameter guide shaft portion 20h. The valve portion 20a has the same outer diameter as the small-diameter guide shaft portion 20g. As shown in Figures 1(b) and 2(b), the valve portion 20a has a substantially fan-shaped shape when viewed from the axis L, and includes a flow path portion 15 that opens at one end along the axis L. As shown in FIG. 3(a), the small-diameter guide shaft portion 20g, the one-end step portion 20i, and the large-diameter guide shaft portion 20h each have sliding portions that slidably engage with the small-diameter guide portion 11ca, the step portion 11e, and the large-diameter guide portion 11cb of the guide member 11, respectively. This allows the valve element 20 in the first embodiment to have a relatively small radial size and lightweight, thereby improving energy efficiency in the stepping motor 30. The other end of the valve element 20 also includes a other-end step portion 20ka that is fixed to the hub 35 of the magnet rotor 32, and a other-end bottomed cylindrical portion 20c that extends along the axis L to the other end and opens. The other-end bottomed cylindrical portion 20c accommodates a support member 40 that biases the valve element 20 toward the one end.

As shown in Figures 2(a) and 3(b), the valve body 20 has a protrusion 20kb that hangs down from the disk portion 20k. When the valve portion 20a rotates relative to the guide member 11, this protrusion 20kb abuts against the drawn-out portion 11g of the guide member 11, which functions as a stopper, thereby restricting the rotation of the valve portion 20a. Note that, as shown in Figure 3(b), the other end 11h of the guide member 11 is spaced apart from the disk portion 20k of the valve body 20.

The stepping motor 30 comprises a case 31, a magnet rotor 32, and a stator coil 33.

The case 31 is made of a metal such as stainless steel and is formed in a generally cylindrical shape with a closed upper end, defining the back pressure chamber 16 that houses the valve body 20 and magnet rotor 32. The lower open end of the case 31 is hermetically fixed to the outer periphery of the bottom cover 12 by welding or the like.

The magnet rotor 32 integrally comprises a cylindrical magnet portion 34 whose outer periphery is magnetized with multiple poles, and a hub 35 connected to the inner periphery of the magnet portion 34 via spokes. The valve element 20 is inserted into the inside of the hub 35 of the magnet rotor 32 toward the other end in the direction of the axis L, with the other end step 20ka of the valve element 20 abutting against one end of the hub 35. The bushing 43 of the support member 40 (described below) is assembled into the other end bottomed cylindrical portion 20c and abutted against the other end of the hub 35. The magnet rotor 32 and valve element 20, which form the rotor portion, are then integrally fixed to the hub 35 by welding or the like. This allows the rotor portion to rotate about the axis L within the case 31.

The stator coil 33 is arranged on the outer peripheral surface of the case 31, and when a pulse signal is applied to the stator coil 33, the magnet rotor 32 rotates according to the number of pulses.

In this way, when the magnet rotor 32 rotates, the valve portion 20a rotates together with the magnet rotor 32 relative to the valve port 11a, changing the opening between the flow path portion 15 and the valve port 11a and controlling the flow rate of fluid flowing from the first joint pipe 1 to the second joint pipe 2 (or from the second joint pipe 2 to the first joint pipe 1).

The support member 40 includes a spring bearing portion 41 that is rotatably arranged in contact with the case 31, a bushing 43 that is fixed to the bottomed cylindrical portion 20c on the other end and the hub 35, and a biasing spring 42 that is sandwiched between the spring bearing portion 41 and the bushing 43 and biases the valve body 20 toward one end.

<Operation of the motor-operated valve>
The operation of the motor-operated valve 100a will be described using Figures 1 and 2. Here, the motor-operated valve 100a will be described as being used in a refrigerant circuit, but this is not limited thereto. In the motor-operated valve 100a, the first coupling pipe 1 is connected to the high-pressure (primary pressure) side, and the second coupling pipe 2 is connected to the low-pressure (secondary pressure) side. Note that a similar explanation can be given for the case where the second coupling pipe 2 is connected to the high-pressure side and the first coupling pipe 1 is connected to the low-pressure side (broken lines in Figures 1(a) and 1(b)), in which refrigeration flows in the opposite direction, and therefore this description will be omitted here.

First, as shown in FIG. 1(b), the valve portion 20a is rotated counterclockwise by the magnet rotor 32. As a result, the protrusion 20kb of the valve element 20 abuts against the drawn-out portion 11g of the guide member 11 (not shown), restricting the rotation of the valve portion 20a and the magnet rotor 32. At this time, the flow path portion 15 faces the valve port 11a, resulting in an open valve state. Therefore, fluid flows from the high-pressure first port 1a to the low-pressure second port 2a, as indicated by the solid arrows in FIGS. 1(a) and 1(b). To prevent pressure loss in the fluid path, the flow path areas of the flow path chamber 13 and flow path portion 15, located before and after the valve port 11a, are set larger than the flow path area of the valve port 11a.

Next, as shown in FIG. 2(b), the valve portion 20a is rotated clockwise by the magnet rotor 32. As shown in FIG. 2(a), the protrusion 20kb of the valve element 20 abuts against the extended portion 11g of the guide member 11, restricting the rotation of the valve portion 20a and the magnet rotor 32. At this time, the flow path portion 15 faces the valve seat 11b, and the valve port 11a faces the seal portion 20aa, resulting in a closed valve state. This closes the flow path from the high-pressure side first port 1a to the low-pressure side second port 2a. Note that, in this embodiment, the valve portion 20a of the valve element 20 and the small-diameter guide shaft portion 20g have the same outer diameter; however, the refrigeration cycle system requires a small amount of fluid to pass through even when the motor-operated valve 100a is closed. In this case, the flow rate required when the valve is closed can be set arbitrarily by making the outer diameter of the valve portion 20a smaller than the outer diameter of the small-diameter guide shaft portion 20g and adjusting the amount of gap between the valve port 11a and the seal portion 20aa.

The flow path portion 15 in the first embodiment has a generally fan-shaped shape when viewed from the direction of the axis L. Therefore, in the motor-operated valve 100a in the first embodiment, when the flow path portion 15 rotates relative to the valve port 11a and transitions from one of the valve open state and the valve closed state to the other, the flow path area rapidly decreases or increases immediately after the transition, allowing it to be used, for example, as an on-off valve.

In the first embodiment, the flow path portion 15 had a generally fan-shaped configuration when viewed from the direction of the axis L, but this is not limited to this. For example, if the flow path portion 15 in the first embodiment has a semicircular shape that is eccentric with respect to the axis L when viewed from the direction of the axis L, in the electrically operated valve 100a, the flow path portion 15 rotates relative to the valve port 11a, and when the valve transitions from one of the open and closed states to the other, the flow path area gradually decreases or increases, enabling precise flow rate control, and the valve can be used, for example, as a flow rate adjustment valve. Furthermore, in the first embodiment, when the flow path portion 15 has a shape that combines a substantially fan-shaped shape and a semicircular shape that is eccentric with respect to the axis L when viewed from the direction of the axis L, in the motor-operated valve 100a, when the flow path portion 15 rotates relative to the valve port 11a and transitions from one of the valve open state and the valve closed state to the other, the flow path area decreases abruptly immediately after the transition and then gradually decreases, or the flow path area changes gradually and then rapidly increases, so that the motor-operated valve can be used, for example, as an opening/closing valve with added flow rate adjustment valve functionality.

<Details of the sliding part>
As described above with reference to FIG. 10 , in the conventional motor-operated valve 1000, the sliding portion consisting of the guide portion 1011c and the guide shaft portion 1020g is made of either metallic materials or metallic materials coated with synthetic resin. Therefore, when the conventional motor-operated valve 1000 is used in a refrigeration cycle system operated in an oil-free or low-oil state, there is no fluid lubrication film of refrigerant oil between the guide portion 1011c and the guide shaft portion 1020g, or only a relatively thin fluid lubrication film. This can result in significant mechanical wear, such as adhesion wear on the sliding surfaces or abrasive wear due to unevenness on the sliding surfaces, which can increase the sliding resistance of the sliding portion. Therefore, the conventional motor-operated valve still fails to solve the problem of increased sliding resistance.

In response to this, the motor-operated valve 100a in the first embodiment takes the following first measure (improving the material of the sliding part) to resolve the conventional problem (increased sliding resistance). In addition, as will be described in detail below, after taking the first measure (improving the material of the sliding part), further measures (heat-resistant means for the sliding part) and third measures (cooling means for the sliding part (valve part)) are taken to address concerns.

<First measure (improving the material of the sliding part)>
In the motor-operated valve 100a of the first embodiment, the first measure (improving the material of the sliding part) is to solve the conventional problem (increased sliding resistance) by improving the material of the sliding part, etc. Specifically, in the motor-operated valve 100a of the first embodiment, the valve body 20 and the guide member 11 that make up the sliding part are both made of a resin material.

Generally, resin materials have a relatively low coefficient of dynamic friction (e.g., approximately 0.04 for polytetrafluoroethylene (PTFE), approximately 0.11 for ultra-high molecular weight polyethylene, and approximately 0.18 for monomer cast nylon), resulting in extremely good sliding properties. Furthermore, the sliding parts of the motor-operated valve 100a of the first embodiment have relatively low surface pressure and relative sliding speed, and the sliding time is also relatively short. Therefore, in the motor-operated valve 100a of the first embodiment, as a first measure (improving the material of the sliding parts), the valve body 20 and guide member 11 are both made of resin material. This significantly reduces dynamic friction even in oil-free or low-oil conditions, thereby resolving the conventional problem (increased sliding resistance) and enabling smooth rotation of the sliding parts. As a result, the operability and durability of the sliding parts of the motor-operated valve 100a can be improved.

Here, even if the first measure (improving the material of the sliding part) is adopted in the motor-operated valve 100a of the first embodiment, if an unexpected event occurs and the surface pressure and relative sliding speed of the sliding part (valve element 20 and guide member 11) become relatively high, the dynamic friction force may become extremely large, and relatively high frictional heat (e.g., 200°C) may be generated. In this case, since the melting point of typical resin materials is between 100 and 200°C, if resin materials melt together, there is a risk of them welding together (hereinafter referred to as the "concern (melting of the sliding part)"). Therefore, in the first embodiment, the second measure (heat-resistant means for the sliding part) is further adopted to resolve the concern (melting of the sliding part) and further improve the operability and durability of the sliding part.

<Second measure (heat-resistant means for sliding parts)>
In the motor-operated valve 100a of the first embodiment, as a second measure (heat resistance of the sliding parts), polyphenylene sulfide (PPS) containing polytetrafluoroethylene (PTFE) is used as the resin material for the valve body 20 and the guide member 11. This PPS has very high heat resistance (for example, the heat resistance temperature of PPS is about 220°C) and good lubricity.

As a result, by adopting the second measure (heat-resistant means for the sliding part) in the motor-operated valve 100a of the first embodiment, the sliding part has extremely high heat resistance and lubricity, so even if an unexpected event occurs and relatively high frictional heat is generated, the resin material will not melt, eliminating the concern (melting of the sliding part) and further improving the operability and durability of the sliding part.

In addition, in the motor-operated valve 100a of the first embodiment, the resin material of the valve body 20 and guide member 11 may be PPS, which is polytetrafluoroethylene (PTFE) reinforced with glass fiber or carbon fiber. This PPS has extremely high tensile strength (e.g., 150 MPa) and heat resistance (e.g., heat resistance temperature of approximately 230°C).

As a result, by adopting the second measure (heat-resistant means for the sliding part) in the motor-operated valve 100a of the first embodiment, the sliding part has extremely high heat resistance and strength, so even if an unexpected event occurs and relatively high frictional heat is generated, the resin material will not melt, eliminating the concern (melting of the sliding part) and further improving the operability and durability of the sliding part.

<Third measure (cooling means for sliding part (valve part))>
In the motor-operated valve 100a of the first embodiment, even if the second measure (heat-resistant means for the sliding part) is adopted to resolve the concern (melting of the sliding part), frictional heat is still generated in the sliding part, and if no measures are taken to prevent this frictional heat from being generated, there is a concern that even slight dimensional changes will occur in the sliding part made of a resin material, causing the sliding part to deviate from its optimal sliding state (hereinafter referred to as the "concern (dimensional change of the sliding part)"). Therefore, the motor-operated valve 100a of the first embodiment employs the third measure (cooling means (valve part) for the sliding part) to resolve the concern (dimensional change of the sliding part).

As shown in Figure 3(a), the motor-operated valve 100a of the first embodiment has a radial support means for supporting the valve element 20 in the radial direction by sliding engagement between the small-diameter guide shaft portion 20g and the small-diameter guide portion 11ca, and between the large-diameter guide shaft portion 20h and the large-diameter guide portion 11cb, and an axial support means for supporting the valve element 20 in the axial direction by sliding engagement between the one-end step portion 20i and the stepped portion 11e. Here, as a third measure (cooling means for sliding parts (valve portion)), the motor-operated valve 100a of the first embodiment sets the one-end radial gap G1 (radial gap) adjacent to the valve portion 20a smaller than the other-end radial gap G2 (radial gap) (G1 < G2). Specifically, as shown in FIG. 3(a), the radial support means defines a radial gap G1 between the small-diameter guide shaft portion 20g, which has the valve portion 20a at one end, and the small-diameter guide portion 11ca, which is smaller than the radial gap G2 between the large-diameter guide shaft portion 20h and the large-diameter guide portion 11cb. Thus, when the third measure (cooling means for the sliding portion (valve portion)) is adopted in the motor-operated valve 100a of the first embodiment, the actual sliding portion is comprised of the small-diameter guide shaft portion 20g, which has the valve portion 20a at one end, and the small-diameter guide portion 11ca. Furthermore, the relatively small sliding area of the radial support means reduces sliding resistance, further improving the operability and durability of the sliding portion. Furthermore, because the radial gap G1 is relatively small, the sealing performance of the valve portion 20a in the valve closed state is improved, as shown in FIG. 2(b), and valve leakage is suppressed.

To specifically explain the third measure (cooling means for the sliding portion (valve portion)), let us consider the temperature of the fluid in the motor-operated valve 100a of the first embodiment using Figure 1(a). First, when the fluid flows from the first port 1a into the flow path chamber 13, it is at a medium temperature (e.g., approximately 60 to 70°C). However, when the fluid flows through the valve port 11a and the flow path portion 15 into the internal flow path 14, it expands (decompresses) and becomes a low temperature (e.g., approximately -10 to 20°C). As a result, when the valve portion 20a is in the open state, the low-temperature fluid actively cools the valve portion 20a. Therefore, by adopting the third measure (cooling means for the sliding portion (valve portion)), not only the valve portion 20a but also the small-diameter guide shaft portion 20g and small-diameter guide portion 11ca, which have the valve portion 20a on one end, are actively cooled. This eliminates the concern (dimensional change in the sliding portion) and further improves the operability and durability of the sliding portion.

As described above, the motor-operated valve 100a in the first embodiment employs the first measure (improving the material of the sliding part) to resolve the conventional problem (increased sliding resistance) and improve the operability and durability of the sliding part. Furthermore, the second measure (heat-resistant means for the sliding part) resolves the concern (melting of the sliding part), and the third measure (cooling means (valve part) for the sliding part) resolves the concern (dimensional change of the sliding part), thereby further improving the operability and durability of the sliding part.

The motor-operated valve 100a of the first embodiment employs the first measure (improving the material of the sliding portion), the second measure (heat-resistant means for the sliding portion), and the third measure (cooling means for the sliding portion (valve portion)). However, this is not limiting, and for example, it may employ the first measure (improving the material of the sliding portion), and then employ the second measure (heat-resistant means for the sliding portion) or the third measure (cooling means for the sliding portion (valve portion)).

(Modification of the axial support means of the first embodiment)
3(c) and (d), a modified axial support means of the first embodiment will be described. The modified axial support means of the first embodiment differs from the first embodiment in that the axial support means is disposed apart from the radial support means, but other configurations are the same as those of the first embodiment. Here, the same components are given the same reference numerals, and duplicated explanations will be omitted.

Specifically, as shown in FIG. 3(c), the radial support means radially slidably engages the small-diameter guide shaft portion 20g with the small-diameter guide portion 11ca, and the large-diameter guide shaft portion 20h with the large-diameter guide portion 11cb, as in the first embodiment. Meanwhile, instead of separating the one-end step portion 20i' and the step portion 11e along the axis L as shown in FIG. 3(c), the axial support means slidably engages the one-end surface (axially opposing surface) of the disk portion 20k with the other end portion 11h' (axially opposing surface) of the guide member 11' along the axis L, as shown in FIG. 3(d). In this way, in the motor-operated valve 100b, the axial support means is spaced apart from the radial support means, dispersing frictional heat generated in the sliding portions. This reliably eliminates concerns about the radial support means (dimensional changes in the sliding portions). Furthermore, frictional heat generated in the axial support means can be dissipated into the fluid in the back pressure chamber 16.

As described above, the motor-operated valve 100b in the modified axial support means of the first embodiment, like the first embodiment, employs the first measure (improving the material of the sliding part) to resolve the conventional problem (increased sliding resistance) and improve the operability and durability of the sliding part. Furthermore, employing the second measure (heat-resistant means for the sliding part) and/or the third measure (cooling means (valve part) for the sliding part) can resolve concerns (melting of the sliding part) and/or concerns (dimensional changes in the sliding part), further improving the operability and durability of the sliding part.

In addition, the motor-operated valve 100b in the axial support means variant of the first embodiment positions the axial support means away from the radial support means, dispersing frictional heat generated in the sliding parts, thereby reliably eliminating concerns about the radial support means (dimensional changes in the sliding parts).

(Modifications 1 and 2 of the flow path portion of the first embodiment)
Flow path portion modifications 1 and 2 of the first embodiment will be described using FIG. 4 . Flow path portion modifications 1 and 2 of the first embodiment differ from the flow path portion 15 of the valve portion 20a of the first embodiment in the shapes of the flow path portions 15'', 15''' in the valve portions 20a'', 20a''', but the other basic configurations are the same as those of the first embodiment. Here, the same components are denoted by the same reference numerals, and duplicated explanations will be omitted. Note that FIGS. 4(a), (c) and 4(b), (d) correspond to FIGS. 1(b) and 2(b), respectively, but for convenience, only the valve portions 20a'', 20a''' and the guide member 11 are shown.

(Modification 1 of the flow path portion of the first embodiment)
4( a) and 4(b) , the flow path section 15″ of the valve section 20a″ in the flow path section variation 1 of the first embodiment will be described. This flow path section 15″ differs from the flow path section 15 of the first embodiment in that it has a semicircular shape that is eccentric with respect to the axis L when viewed in the direction of the axis L. However, the other configurations are the same as those of the flow path section 15 of the first embodiment.

When the flow path section 15'' rotates relative to the valve port 11a and transitions from one of the valve open state and the valve closed state to the other, the flow path area gradually decreases or increases. Therefore, the motor-operated valve 100c in flow path section variant 1 of the first embodiment allows for precise flow rate control depending on the rotation angle of the magnet rotor 32, and can therefore be used, for example, as a flow rate adjustment valve.

(Modification 2 of the flow path portion of the first embodiment)
4(c) and 4(d) will be used to describe the flow path section 15''' of the valve section 20a''' in flow path section variant 2 of the first embodiment. This flow path section 15''' differs from the flow path section 15 of the first embodiment in that it has a shape that combines the flow path section 15 of the first embodiment with the flow path section 15'' of flow path section variant 1 of the first embodiment, but other configurations are the same as the flow path section 15 of the first embodiment.

Specifically, when viewed from the direction of the axis L, the flow path section 15''' has a shape that combines a generally fan-shaped shape with a semicircular shape that is eccentric with respect to the axis L. Therefore, in the motor-operated valve 100d in flow path section variant 2 of the first embodiment, when the flow path section 15''' rotates with respect to the valve port 11a and transitions from one of the valve open state and the valve closed state to the other, the flow path area decreases abruptly immediately after the transition and then gradually decreases, or the flow path area changes gradually and then suddenly increases. This combination of abrupt and gradual changes in the flow path area enables flow control, and the motor-operated valve can be used, for example, as an on-off valve with added flow adjustment valve functionality.

As described above, the motor-operated valves 100c, 100d in flow path portion variants 1 and 2 of the first embodiment, like the first embodiment, can resolve the conventional problem (increased sliding resistance) and improve the operability and durability of the sliding portion by adopting the first measure (improving the material of the sliding portion). Furthermore, by adopting the second measure (heat-resistant means for the sliding portion) and/or the third measure (cooling means (valve portion) for the sliding portion), the concerns (melting of the sliding portion) and/or the concerns (dimensional changes in the sliding portion) can be resolved, further improving the operability and durability of the sliding portion.

(Modification of the second joint pipe of the first embodiment)
A modified second coupling pipe of the first embodiment will be described using Figure 5. The connection mode of the second coupling pipe 2' in the modified second coupling pipe of the first embodiment differs from that of the first embodiment in that the second coupling pipe 2' is arranged so as to extend relative to the valve body 10A' in a direction perpendicular to the axis L. However, the other configurations are the same as those of the first embodiment. Here, the same components are denoted by the same reference numerals, and redundant explanations will be omitted.

Specifically, a connection chamber 18 is formed on the bottom side of the bowl-shaped member 10', into which the guide member 11 is fitted and fixed. The second coupling pipe 2' is connected radially from this connection chamber 18. In this way, by arranging the second coupling pipe 2' to extend in a direction perpendicular to the axis L in the motor-operated valve 100e, the height in the direction of the axis L can be reduced.

As described above, the motor-operated valve 100e in the second joint pipe variant of the first embodiment, like the first embodiment, employs the first measure (improving the material of the sliding part) to resolve the conventional problem (increased sliding resistance) and improve the operability and durability of the sliding part. Furthermore, employing the second measure (heat-resistant means for the sliding part) and/or the third measure (cooling means (valve part) for the sliding part) can resolve the concerns (melting of the sliding part) and/or the concerns (dimensional change of the sliding part), further improving the operability and durability of the sliding part.

(Valve body modification of the first embodiment)
A modified valve element of the first embodiment will be described with reference to Figure 6. This modified valve element of the first embodiment differs from the first embodiment in that the valve element 20'''' is provided with pressure equalizing holes (axial hole 20l and through hole 20m) that constantly communicate between the internal flow path 14 and the back pressure chamber 16, but the other configurations are the same as those of the first embodiment. Here, the same components are denoted by the same reference numerals, and redundant explanations will be omitted.

<Configuration of the motor-operated valve>
A motor-operated valve 100f according to a modified valve element of the first embodiment of the present invention will be described using Figure 6. The motor-operated valve 100f is mainly composed of a valve body 10A", a valve element 20"", a stepping motor 30, and a support member 40. Here, the valve body 10A" and the valve element 20"" will be described in order, focusing on the differences from the first embodiment.

Like the first embodiment, the valve body 10A'' is equipped with a circular lower cover 12' integrally molded with the guide member 11. However, unlike the first embodiment, this lower cover 12' does not have a communication hole that constantly connects the flow path chamber 13 and the back pressure chamber 16 and functions as a pressure equalization hole. The rest of the configuration is the same.

The valve element 20'''' differs from the first embodiment in that it has an axial hole 20l that penetrates along the axis L between the internal flow path 14 and the other-end bottomed cylindrical portion 20c, and a through hole 20m that penetrates radially between the other-end bottomed cylindrical portion 20c and the back pressure chamber 16. The other configuration is the same. This through hole 20m is located between the other end 11h of the guide member 11 and the disc portion 20k of the valve element 20''''.

<Fourth measure (cooling means for sliding parts (pressure equalizing holes))>
In the motor-operated valve 100f in the valve body modification of the first embodiment, similarly to the first embodiment, a first measure (improving the material of the sliding part) is taken to solve the conventional problem (increased sliding resistance), and then a second measure (heat-resistant means for the sliding part) and a third measure (cooling means for the sliding part (valve part)) are further taken to address the concerns (melting of the sliding part) and the concerns (dimensional change of the sliding part). Furthermore, in the motor-operated valve 100f in the valve body modification of the first embodiment, a fourth measure (cooling means for the sliding part (pressure equalizing hole)) is taken to address the concern (dimensional change of the sliding part).

Here, the motor-operated valve 100f in the valve body modification of the first embodiment, like the first embodiment, is equipped with radial support means that radially supports the valve body 20'''' through slidable engagement between the small diameter guide shaft portion 20g and the small diameter guide portion 11ca, and axial support means that axially supports the valve body 20'''' through slidable engagement between the one end step portion 20i and the stepped portion 11e. Although not shown, the one end side radial gap G1 (radial gap) is set smaller than the other end side radial gap G2 (radial gap) (G1 < G2) (see Figure 3(a)). Furthermore, as shown in Figure 6, the motor-operated valve 100f according to the valve element modification of the first embodiment has an axial hole 20l, a bottomed cylindrical portion 20c at the other end, and a through-hole 20m formed in the valve element 20'''', which function as a pressure equalizing hole, and the internal flow path 14 and the back pressure chamber 16 are constantly in communication via this pressure equalizing hole.

This overlaps with the explanation for the third measure (cooling means for sliding parts (valve part)), but when the fluid flows into the internal flow path 14 via the valve port 11a and flow path part 15, it expands (decompresses) and becomes colder (for example, approximately -10 to 20°C). Therefore, when the valve is open, this cold fluid is introduced into the axial hole 20l of the valve element 20'''', and the radial support means and axial support means located on one end of the valve element 20'''' are actively cooled from the inside, eliminating the concern (dimensional change in the sliding parts) and ensuring improved operability and durability of the sliding parts.

In addition, in the motor-operated valve 100f in the valve element modification of the first embodiment, the valve element 20'''' has a pressure equalization hole, which makes it possible to maintain the surface pressure of the sliding portion of the axial support means at a desired value in both cases where fluid flows from the first port 1a on the high-pressure side to the second port 2a on the low-pressure side (see the solid line in the figure) (hereinafter referred to as "forward flow"), and where fluid flows from the second port 2a on the high-pressure side to the first port 1a on the low-pressure side (see the dashed line in the figure) (hereinafter referred to as "reverse flow"). The surface pressure of the sliding portion of the axial support means is described in detail below.

<Comparative Example: Surface Pressure of Sliding Portion in First Embodiment>
First, for better understanding, the pressing force caused by the pressure difference occurring on the valve element 20 will be described using the motor-operated valve 100a of the first embodiment shown in FIG. 1 . In this motor-operated valve 100a, the first port 1a is constantly connected to the back pressure chamber 16 via the flow path chamber 13 and the communication hole 12a of the bottom cover 12. Therefore, the pressure introduced into the back pressure chamber 16 fluctuates between the forward flow (see the solid line in the figure) and the reverse flow (see the dashed line in the figure). That is, in the forward flow, the fluid in the back pressure chamber 16 is at high pressure while the fluid in the internal flow path 14 is at low pressure, so that the pressing force caused by the pressure difference occurring in the axial direction L of the valve element 20 is directed toward one end (downward). In contrast, in the reverse flow, the fluid in the back pressure chamber 16 is at low pressure while the fluid in the internal flow path 14 is at high pressure, so that the pressing force caused by the pressure difference occurring in the axial direction L of the valve element 20 is directed toward the other end (upward).

In the motor-operated valve 100a of the first embodiment, therefore, the difference in the pressing force on the valve element 20 due to the differential pressure between forward flow and reverse flow is slightly larger. Therefore, to prevent the valve element 20 from wobbling, the spring load of the biasing spring 42 (which biases the valve element 20 toward one end) is set to withstand the pressing force due to the maximum differential pressure, using the pressing force toward the other end (upward) due to the differential pressure as the reference for reverse flow. As a result, in the motor-operated valve 100a, the surface pressure of the sliding portion of the axial support means is slightly larger in the case of forward flow than in the case of reverse flow, due to the difference in the pressing force caused by the differential pressure.

<Surface pressure of sliding portion of modified valve body of first embodiment>
In contrast, in the motor-operated valve 100f according to the valve element modification of the first embodiment, as shown in FIG. 6, in the case of a forward flow, the fluid in the back pressure chamber 16 and the internal flow path 14 are both at low pressure, so the pressing force due to the pressure difference occurring in the axial direction L of the valve element 20'''' is substantially canceled. In the case of a reverse flow, the fluid in the back pressure chamber 16 and the internal flow path 14 are both at high pressure, so the pressing force due to the pressure difference occurring in the axial direction L of the valve element 20'''' is substantially canceled.

Therefore, in the motor-operated valve 100f according to the valve element modification of the first embodiment, there is no difference in pressing force due to the pressure difference between forward flow and reverse flow, so the spring load of the biasing spring 42 (which biases the valve element 20 toward one end) can be set to the minimum necessary value so that the valve element 20 does not wobble. As a result, in the motor-operated valve 100f, the surface pressure of the sliding portion of the axial support means can be maintained at the desired value in both forward flow and reverse flow.

As described above, the motor-operated valve 100f in the valve body modification of the first embodiment, like the first embodiment, employs the first measure (improving the material of the sliding part) to resolve the conventional problem (increased sliding resistance) and improve the operability and durability of the sliding part. Furthermore, employing the second measure (heat-resistant means for the sliding part) resolves the concern (melting of the sliding part). Additionally, employing the third measure (cooling means for the sliding part (valve part)) and the fourth measure (cooling means for the sliding part (pressure equalizing hole)) reliably resolves the concern (dimensional change of the sliding part), further improving the operability and durability of the sliding part and maintaining the surface pressure of the sliding part in the axial support means at a desired value.

Note that the motor-operated valve 100f in the valve body modification of the first embodiment employs the first measure (improving the material of the sliding portion), the second measure (heat-resistant means for the sliding portion), the third measure (cooling means for the sliding portion (valve portion)), and the fourth measure (cooling means for the sliding portion (pressure equalizing hole)). However, this is not limiting, and for example, it may employ the first measure (improving the material of the sliding portion), and then employ the third measure (cooling means for the sliding portion (valve portion)) and the fourth measure (cooling means for the sliding portion (pressure equalizing hole)).

Second Embodiment
A motor-operated valve 100g according to a second embodiment of the present invention will be described using Figure 7. The motor-operated valve 100g according to the second embodiment differs from the motor-operated valve 100a according to the first embodiment mainly in the radial arrangement of the valve body 20B and the guide member 11B and the connection mode of the first joint pipe 1B and the second joint pipe 2B, but the other basic configuration is substantially the same as that of the first embodiment. Here, the same components are designated by the same reference numerals, and redundant description will be omitted.

As will be described in more detail below, the motor-operated valve 100g of the second embodiment, like the first embodiment, takes the first measure (improving the material of the sliding part) to resolve the conventional problem (increased sliding resistance), and then further takes the second measure (heat-resistant means for the sliding part) and the third measure (cooling means for the sliding part (valve part)) to address the concerns (melting of the sliding part) and (dimensional change of the sliding part).

<Configuration of the motor-operated valve>
7, the motor-operated valve 100g is mainly composed of a valve body 10B, a valve element 20B, a stepping motor 30B, and a support member 40B. Each component of the motor-operated valve 100g will be described below in order.

The valve body 10B comprises a bowl-shaped member 10Ba that defines a portion of the flow path chamber 13, and a guide member 11B that has a generally cylindrical shape extending along the axis L and is fixedly connected to the bottom side of the bowl-shaped member 10Ba.

The bowl-shaped member 10Ba is connected to its bottom side with a first coupling tube 1B and a second coupling tube 2B, which serve as fluid paths for refrigerants and the like. The first coupling tube 1B is directly connected to the flow path chamber 13 via the first port 1Ba. The second coupling tube 2B abuts against one end of the guide member 11B and is connected to the flow path chamber 13 via the second port 2Ba, the internal flow path 14 of the guide member 11B, and the valve port 11Ba (described in detail below). The first coupling tube 1B and the second coupling tube 2B are made of materials such as copper or stainless steel and are fixed to the bowl-shaped member 10Ba by brazing or the like. As shown in FIG. 7(b), the bowl-shaped member 10Ba has a raised portion 10Baa that is located on the opposite side of the axis L from the first coupling tube 1B and that protrudes toward the flow path chamber 13.

The guide member 11B has a significantly different structure from approximately the center along the axis L to one end. First, the guide member 11B from approximately the center along the axis L to one end has a bottomed cylindrical shape. It includes an internal flow path 14 extending along the axis L. At the other end of the internal flow path 14, it has a valve port 11Ba that radially penetrates the guide member 11B. It also has an annular valve seat 11Bb formed around the valve port 11Ba. It also has a guide portion 11Bd that guides the valve body 20B circumferentially. It also has an annular reduced-diameter portion 11Bc (see Figure 7(c)). The reduced-diameter portion 11Bc has a smaller outer diameter than the guide portion 11Bd. Next, the guide member 11B from approximately the center along the axis L to the other end has a solid shape. A flat support portion 11Be is formed at the other end of the guide member 11B. As shown in Figure 7(b), the valve port 11Ba is located on the opposite side of the first port 1Ba from the axis L when viewed in the direction of the axis L. In the second embodiment, the shape of the valve port 11Ba when viewed in a direction perpendicular to the axis L is circular, but this is not limited to this and various shapes can be used, such as a rectangular shape, an elliptical shape, or any asymmetric shape.

In the second embodiment, the bowl-shaped member 10Ba and the guide member 11B are separate bodies, but this is not limited thereto. For example, the bowl-shaped member 10Ba and the guide member 11B may be formed as a single unit, as in the conventional motor-operated valve shown in Figure 10.

The valve element 20B is a member extending along the axis L. A valve portion 20Ba is formed at one end of the valve element 20B. The inside of the valve element 20B is provided with a bottomed cylindrical portion 20Bb extending toward one end along the axis L, and a bottomed cylindrical portion 20Bc extending toward the other end along the axis L. The outer periphery of the valve element 20B is provided with a flange portion 20Bg protruding in a disk shape from the radially outer side of the valve portion 20Ba, and a protrusion 20Be extending from the flange portion 20Bg, protruding from the radially outer side of the valve portion 20Ba, and capable of abutting against the raised portion 10Baa of the bowl-shaped member 10Ba as the valve element 20B rotates. Furthermore, the outer periphery of the valve body 20B is provided with a step 20Bd into which the magnet rotor 32B fits and abuts, and an annular groove 20Bf that holds the retaining ring 17, as will be described in detail below.

The guide member 11B, which guides the valve element 20B in the circumferential direction, is inserted into the bottomed cylindrical portion 20Bb with a small radial gap allowing for sliding movement. The bottomed cylindrical portion 20Bb and the guide portion 11Bd have sliding portions that slidably engage with each other. This increases the stability of the rotational state of the valve element 20B. The other end 20Bba of the bottomed cylindrical portion 20Bb, which abuts against the support portion 11Be of the guide member 11B, has a flat shape corresponding to the support portion 11Be. The sliding engagement between the other end 20Bba and the support portion 11Be provides an axial support means that supports the valve element 20B in the axial direction. Furthermore, the one-end bottomed cylindrical portion 20Bb, as will be described in detail later, has a seal portion 20Baa that is in annular sliding contact with the valve seat 11Bb of the guide member 11B, and a flow path portion 15B that has a shape that, when viewed from the direction of the axis L, is a combination of a substantially fan shape and a semicircular shape that is eccentric with respect to the axis L, and that extends and opens to one end side in the direction of the axis L. As shown in FIG. 7A , one end of this flow path portion 15B is located on one end side in the direction of the axis L with respect to the valve port 11Ba, and the other end of the flow path portion 15B is located on the other end side in the direction of the axis L with respect to the valve port 11Ba. Note that, although the shape of the support portion 11Be of the guide member 11B is flat in the second embodiment, it is not limited to this and may be, for example, a hemispherical shape or a convex shape. This significantly reduces the contact area between the support portion 11Be of the guide member 11B and the other end portion 20Bba of the valve body 20B, reducing sliding resistance and making it easier for the valve body 20B to rotate.

The bottomed cylindrical portion 20Bc on the other end accommodates a support member 40B that biases the valve body 20B toward one end.

As a result, the valve portion 20Ba rotates relative to the guide member 11B, changing the state of communication between the flow path portion 15B of the valve portion 20Ba and the valve port 11Ba of the guide member 11B between an open valve state (see FIGS. 7(a) and 7(b)) and a closed valve state (not shown) (or minimum opening), thereby adjusting the flow rate. At this time, as shown in FIG. 7(b), the protrusion 20Be of the valve portion 20Ba abuts against the raised portion 10Baa, which functions as a stopper, restricting the rotation of the valve portion 20Ba and the magnet rotor 32B. This prevents the valve portion 20Ba from moving beyond the position where the valve is open or the position where the valve is closed (or minimum opening), ensuring stable, reliable positioning with reproducibility.

The stepping motor 30B includes a case 31B, a magnet rotor 32B, and a stator coil 33B.

The case 31B is made of a metal such as stainless steel and is formed in a generally cylindrical shape with a closed upper end, defining the back pressure chamber 16 that houses the valve body 20B and magnet rotor 32B. The lower open end of the case 31B is hermetically fixed to the upper end of the bowl-shaped member 10Ba by welding or the like.

The magnet rotor 32B integrally comprises a cylindrical magnet portion 34B whose outer periphery is magnetized with multiple poles, and a hub 35B connected to the inner periphery of the magnet portion 34B via spokes. The magnet rotor 32B is fixed to the valve body 20B by abutting one end of the hub 35B against the step portion 20Bd and clamping the other end of the hub 35B with a retaining ring 17 so that it is biased in the direction of the axis L. As a result, the rotor portion integrally includes the magnet rotor 32B and the valve body 20B and is rotatable about the axis L within the case 31B.

The stator coil 33B is arranged on the outer peripheral surface of the case 31B, and when a pulse signal is applied to the stator coil 33B, the magnet rotor 32B rotates according to the number of pulses.

In this way, when the magnet rotor 32B rotates, the valve portion 20Ba rotates with the magnet rotor 32B relative to the valve port 11Ba, changing the opening between the flow path portion 15B and the valve port 11Ba. As will be described in more detail below, this controls the flow rate of fluid flowing from the first joint pipe 1B to the second joint pipe 2B (or from the second joint pipe 2B to the first joint pipe 1B).

The support member 40B includes a spring bearing portion 41 that is rotatably arranged in contact with the case 31B, and a biasing spring 42 that is sandwiched between the spring bearing portion 41 and the valve body 20B and biases the valve body 20B toward one end.

<Operation of the motor-operated valve>
The operation of the motor-operated valve 100g will be described using Figure 7. Here, the motor-operated valve 100g will be described as being used in a refrigerant circuit, but this is not limited thereto. In addition, the motor-operated valve 100g will be described in the case where the first joint pipe 1B is connected to the high-pressure (primary pressure) side and the second joint pipe 2B is connected to the low-pressure (secondary pressure) side (solid line in Figure 7(a)). Note that the same explanation can be given for the case where the second joint pipe 2B is connected to the high-pressure side and the first joint pipe 1B is connected to the low-pressure side (dashed line in Figure 7(a)), which is the opposite direction of flow, and therefore this will not be described here.

First, as shown in FIG. 7(b), the valve portion 20Ba is rotated counterclockwise (in the direction of the arrow) by the magnet rotor 32B. This causes the protrusion 20Be of the valve portion 20Ba to abut against the raised portion 10Baa of the bowl-shaped member 10Ba, restricting the rotation of both the valve portion 20Ba and the magnet rotor 32B. At this time, the flow path portion 15B faces the valve port 11Ba, resulting in an open valve. Therefore, fluid flows from the high-pressure first port 1Ba to the low-pressure second port 2Ba, as indicated by the solid arrows in FIG. 7(a). To prevent pressure loss in the fluid path, the flow path areas of the flow path portion 15B and the internal flow path 14, located before and after the valve port 11Ba, are set larger than the flow path area of the valve port 11Ba.

Next, although not shown, the valve portion 20Ba is rotated clockwise by the magnet rotor 32B, causing the protrusion 20Be of the valve portion 20Ba to abut against the raised portion 10Baa of the bowl-shaped member 10Ba, restricting the rotation of the valve portion 20Ba and also restricting the rotation of the magnet rotor 32B. At this time, the flow path portion 15B faces the valve seat 11Bb, and the valve port 11Ba faces the seal portion 20Baa, resulting in a closed valve state. This closes the flow path from the high-pressure side first port 1Ba to the low-pressure side second port 2Ba.

In the second embodiment, the flow path portion 15B has a shape that combines a generally fan-shaped shape and a semicircular shape that is eccentric with respect to the axis L when viewed from the direction of the axis L. Therefore, in the second embodiment, when the flow path portion 15B rotates with respect to the valve port 11Ba and transitions from one of the valve open state (see FIG. 7(b)) and the valve closed state (not shown) to the other, the flow path area decreases abruptly immediately after the transition, and then gradually decreases, or the flow path area changes gradually, and then suddenly increases. In this way, the motor-operated valve 100g in the second embodiment is capable of flow rate control by a combination of abrupt and gradual changes in the flow path area, and can therefore be used, for example, as an on-off valve with added flow rate adjustment valve functionality.

While the flow path portion 15B in the second embodiment has a shape that combines a generally fan-shaped shape with a semicircular shape that is eccentric with respect to the axis L when viewed from the axis L, the shape is not limited to this. For example, if the flow path portion 15B in the second embodiment has a generally fan-shaped shape when viewed from the axis L, in the motor-operated valve 100g, the flow path portion 15B rotates relative to the valve port 11Ba, and when the motor-operated valve 100g transitions from one of the valve open state and the valve closed state to the other, the flow path area rapidly decreases or increases immediately after the transition, allowing the motor-operated valve 100g to be used, for example, as an on-off valve. Furthermore, if the flow path portion 15B in the second embodiment has a semicircular shape that is eccentric with respect to the axis L when viewed from the axis L, in the motor-operated valve 100g, the flow path portion 15B rotates relative to the valve port 11Ba, and when the motor-operated valve 100g transitions from one of the valve open state and the valve closed state to the other, the flow path area gradually decreases or increases, allowing for precise flow rate control, allowing the motor-operated valve 100g to be used, for example, as a flow regulation valve.

Here, in the motor-operated valve 100g of the second embodiment, similar to the first embodiment, a first measure (changing the material of the sliding part) is taken to resolve the conventional problem (increased sliding resistance), and then a second measure (heat-resistant means for the sliding part) and a third measure (cooling means for the sliding part (valve part)) are further taken to address the concerns (melting of the sliding part) and (dimensional change of the sliding part).

<First measure (improving the material of the sliding part)>
In the electric valve 100g of the second embodiment, as in the first embodiment, the first measure (improving the material of the sliding part) is adopted, that is, the material constituting the sliding part (valve body 20B and guide member 11B) is improved and both are made of resin material, thereby solving the conventional problem (increased sliding resistance).

<Second measure (heat-resistant means for sliding parts)>
In the electric valve 100g of the second embodiment, as in the first embodiment, a second measure (heat-resistant means for the sliding parts) is adopted, that is, the resin material of the valve body 20B and the guide member 11B is polyphenylene sulfide (PPS) with polytetrafluoroethylene (PTFE) added, preferably PPS with glass fiber or carbon fiber added as a reinforcing agent in addition to polytetrafluoroethylene (PTFE), thereby eliminating the concern (melting of the sliding parts).

<Third measure (cooling means for sliding part (valve part))>
In the motor-operated valve 100g of the second embodiment, similarly to the first embodiment, the third measure (cooling means for the sliding portion (valve portion)) is adopted to resolve the concern (dimensional change of the sliding portion). The third measure (cooling means for the sliding portion (valve portion)) will be specifically described below.

As shown in Figure 7(c), the motor-operated valve 100g of the second embodiment has a radial support means for radially supporting the valve element 20B through sliding engagement between the bottomed cylindrical portion 20Bb at one end and the guide portion 11Bd and reduced diameter portion 11Bc. Here, as a third measure (cooling means for the sliding portion (valve portion)), the motor-operated valve 100g of the second embodiment sets the radial gap G1' (radial gap) at one end adjacent to the valve portion 20Ba smaller than the radial gap G2' (radial gap) at the other end (G1' < G2'). Specifically, as shown in Figure 7(c), in the radial support means, the one-end radial gap G1' between the one-end bottomed cylindrical portion 20Bb, which has the valve portion 20Ba on one end, and the guide portion 11Bd is set smaller than the other-end radial gap G2' between the one-end bottomed cylindrical portion 20Bb and the reduced diameter portion 11Bc. In this way, when the third measure (cooling means for the sliding portion (valve portion)) is adopted in the motor-operated valve 100g of the second embodiment, the sliding portion is essentially composed of the one-end bottomed cylindrical portion 20Bb, which has the valve portion 20Ba on one end, and the guide portion 11Bd.

As in the first embodiment, when the fluid flows into the internal flow path 14 via the flow path portion 15B and the valve port 11Ba, it expands (decompresses) and becomes colder (e.g., approximately -10 to 20°C). Therefore, when this cold fluid is introduced into the internal flow path 14 of the valve element 20B in the open state, the radial support means located on one end of the valve element 20B in particular is actively cooled from the inside, eliminating concerns (dimensional changes in the sliding portion) and reliably improving the operability and durability of the sliding portion. Furthermore, the sliding area of the radial support means can be made relatively small, reducing sliding resistance, further improving the operability and durability of the sliding portion. Furthermore, because the one-end radial gap G1' is relatively small, the sealing performance of the valve element 20Ba in the closed state is improved, suppressing valve leakage.

As described above, the motor-operated valve 100g of the second embodiment employs the first measure (improving the material of the sliding part) to resolve the conventional problem (increased sliding resistance) and improve the operability and durability of the sliding part. Furthermore, the second measure (heat-resistant means for the sliding part) eliminates the concern (melting of the sliding part), and the third measure (cooling means (valve part) for the sliding part) eliminates the concern (dimensional change of the sliding part), thereby further improving the operability and durability of the sliding part.

The motor-operated valve 100g in the second embodiment employs the first measure (improving the material of the sliding portion), the second measure (heat-resistant means for the sliding portion), and the third measure (cooling means for the sliding portion (valve portion)). However, this is not limiting, and for example, it may employ the first measure (improving the material of the sliding portion), and then employ the second measure (heat-resistant means for the sliding portion) or the third measure (cooling means for the sliding portion (valve portion)).

(Modification of the stopper portion of the second embodiment)
A modified stopper portion of the second embodiment will be described using Figure 8. The connection mode of the first joint pipe 1B' in the modified stopper portion of the second embodiment differs from that of the second embodiment in that the first joint pipe 1B' extending in a direction perpendicular to the axis L is disposed at a position where the first joint pipe 1B' functions as a stopper portion for the valve portion 20Ba, and the raised portion 10Baa is omitted. However, the other configuration is the same as that of the second embodiment. Here, the same components are denoted by the same reference numerals, and redundant description will be omitted.

Specifically, the first coupling pipe 1B' is positioned in the bowl-shaped member 10Ba' so that it overlaps with the protrusion 20Be when viewed from a direction perpendicular to the axis L, as shown in FIG. 8(a), and so that it interferes with the rotating protrusion 20Be when viewed from the direction of the axis L, as shown in FIG. 8(b). This first coupling pipe 1B' abuts against the rotating protrusion 20Be, restricting it to the desired rotation angle, enabling reproducible, stable, and reliable positioning. In this way, the first coupling pipe 1B' functions as a stopper for the valve portion 20Ba, eliminating the need for the raised portion 10Baa and reducing costs.

As described above, the motor-operated valve 100h in the modified stopper portion of the second embodiment, like the second embodiment, employs the first measure (improving the material of the sliding portion) to resolve the conventional problem (increased sliding resistance) and improve the operability and durability of the sliding portion. Furthermore, by employing the second measure (heat-resistant means for the sliding portion) and/or the third measure (cooling means (valve portion) for the sliding portion), the concerns (melting of the sliding portion) and/or the concerns (dimensional changes in the sliding portion) can be resolved, further improving the operability and durability of the sliding portion.

<About the refrigeration cycle system>
The refrigeration cycle system of the present invention will be described with reference to Figure 9. The refrigeration cycle system includes an expansion valve 100 using the motor-operated valves 100a to 100h of the first and second embodiments, an outdoor heat exchanger 200 mounted in an outdoor unit, an indoor heat exchanger 300 mounted in an indoor unit, a flow path switching valve 400 constituting a four-way valve, and a compressor 500. The expansion valve 100, the outdoor heat exchanger 200, the indoor heat exchanger 300, the flow path switching valve 400, and the compressor 500 are connected to each other by conduits to form a heat pump type refrigeration cycle. Note that the accumulator, pressure sensor, temperature sensor, etc. are not shown in the figure.

The flow path of the refrigeration cycle can be switched between two paths by the flow path switching valve 400: one for cooling operation and one for heating operation. During cooling operation (see the solid arrow in the diagram), the refrigerant compressed by the compressor 500 is circulated from the flow path switching valve 400 through the outdoor heat exchanger 200, expansion valve 100, indoor heat exchanger 300, flow path switching valve 400, and finally the compressor 500, with the outdoor heat exchanger 200 functioning as a condenser and the indoor heat exchanger 300 functioning as an evaporator.

On the other hand, during heating operation (see dashed arrow in the figure), the refrigerant compressed by the compressor 500 is circulated from the flow path switching valve 400 through the indoor heat exchanger 300, expansion valve 100, outdoor heat exchanger 200, flow path switching valve 400, and then the compressor 500, with the indoor heat exchanger 300 functioning as a condenser and the outdoor heat exchanger 200 functioning as an evaporator. Therefore, the expansion valve 100 decompresses and expands the liquid refrigerant flowing in from the outdoor heat exchanger 200 during cooling operation, or the liquid refrigerant flowing in from the indoor heat exchanger 300 during heating operation, and can further control the flow rate of that refrigerant.

The present invention is not limited to the first and second embodiments, but includes other configurations that can achieve the objects of the present invention, and the following modifications are also included in the present invention. For example, the first and second embodiments illustrate motor-operated valves 100a-100h used in air conditioners such as residential air conditioners, but the motor-operated valves of the present invention are not limited to residential air conditioners, but may also be used in commercial air conditioners, and are not limited to air conditioners, but can also be applied to various types of refrigeration machines, etc.

<Others>
The motor-operated valves 100a to 100h of the present embodiment are applicable not only to the refrigeration cycle illustrated, but also to any other fluid device and fluid circuit. The present invention is not limited to the above-described aspects, embodiments, and modifications, and can be modified as appropriate without departing from the technical concept of the present invention.

100a to 100h Motor-operated valve 1, 1B, 1B' First joint pipe 1a, 1Ba, 1Ba' First port 2, 2', 2B Second joint pipe 2a, 2Ba Second port 10A, 10A', 10A'', 10B Valve body 10, 10', 10Ba, 10Ba' Bowl-shaped member 10Baaa Raised portion 11, 11', 11B Guide member 11a, 11Ba Valve port 11b, 11Bb Valve seat 11ca Small diameter guide portion 11cb Large diameter guide portion 11e Step portion 11g Pulled-out portion 11h, 11h' Other end portion 11Bc Reduced diameter portion 11Bd Guide portion 11Be Support portion 12, 12' Lower cover 12a Communication hole 13 Flow path chamber 14 Internal flow path 15, 15", 15'", 15B Flow path portion 16 Back pressure chamber 17 Retaining ring 18 Connecting chamber 20, 20', 20"", 20B Valve body 20a, 20a", 20a'", 20Ba Valve portion 20aa, 20Baaa Seal portion 20c, 20Bc Other end side bottomed cylindrical portion 20g Small diameter guide shaft portion 20h Large diameter guide shaft portion 20i, 20i' One end side step portion 20k Disk portion 20ka Other end side step portion 20kb, 20Be Projection portion 20l Shaft hole (pressure equalizing hole)
20m through hole (equalizing hole)
20Bb One end side bottomed cylindrical portion 20Bba Other end portion 20Bd Step portion 20Bf Annular groove 20Bg Flange portion 30, 30B Stepping motor 31, 31B Case 32, 32B Magnet rotor 33, 33B Stator coil 34, 34B Magnet portion 35, 35B Hub 40, 40B Support member 41 Spring bearing portion 42 Biasing spring 43 Bush 100 Expansion valve 200 Outdoor heat exchanger 300 Indoor heat exchanger 400 Flow path switching valve 500 Compressor

G1, G1' One end side radial clearance G2, G2' Other end side radial clearance L Axis

Claims (8)

a valve body having a valve portion provided on one end side thereof, and a rotor portion having a rotor that rotates integrally with the valve body;
a valve body including a flow path chamber that accommodates the valve portion, a valve seat that faces the valve portion in a radial direction, and a valve port that extends in a radial direction and is capable of communicating with the flow path chamber;
a case connected to the valve body and defining a back pressure chamber of the rotor portion;
Equipped with
the valve body has a first port directly communicating with the flow path chamber, a second port communicating with the valve port, and a guide member that supports the valve element, which is provided along an axis, in the axial direction and guides it in a circumferential direction,
the valve portion has a seal portion that closes the valve port and a flow path portion that can communicate with the valve port,
the rotation of the rotor changes the state of communication between the valve port and the flow path portion, thereby controlling the flow rate of the fluid flowing through the valve port;
The valve body and the guide member constitute a sliding portion, and are made of a resin material. The motor-operated valve described in claim 1, characterized in that the resin material is PPS with added PTFE. The motor-operated valve according to claim 2, characterized in that the resin material contains glass fiber or carbon fiber as a reinforcing agent. a radial support means for supporting the valve body in the radial direction, the radial support means being set in a predetermined radial gap between the valve body and the guide member, the sliding portion;
2. The motor-operated valve according to claim 1, wherein the radial support means has a one-end radial gap adjacent to the valve portion and an other-end radial gap adjacent to the other end side of the one-end radial gap, and the one-end radial gap is set smaller than the other-end radial gap. The valve body has, in order from one end side to the other end side, a small diameter guide shaft portion having the valve portion on one end side and a large diameter guide shaft portion,
The guide member has a small diameter guide portion and a large diameter guide portion in this order from one end side to the other end side,
5. The motor-operated valve according to claim 4, wherein the one-end radial gap between the small-diameter guide shaft portion and the small-diameter guide portion is set smaller than the other-end radial gap between the large-diameter guide shaft portion and the large-diameter guide portion. The valve valve further includes an axial support means for supporting the valve in the axial direction by engaging the axially opposing surfaces of the valve body and the guide member, the sliding portion being the valve body, in the axial direction.
the first port communicates with the valve port via the flow path chamber;
6. The motor-operated valve according to claim 5, wherein the valve element extends along an axis and has a pressure equalizing hole that constantly communicates the second port with the back pressure chamber. the valve body has an annular step portion at the boundary between the small diameter guide shaft portion and the large diameter guide shaft portion,
the guide member has an annular step portion at a boundary between the small diameter guide portion and the large diameter guide portion,
7. The motor-operated valve according to claim 6, wherein the axial support means engages the step portion of the valve body and the step portion of the guide member with each other. A refrigeration cycle system including a compressor, a condenser, an expansion valve, and an evaporator, wherein the motor-operated valve described in any one of claims 1 to 7 is used as the expansion valve.