Electric valve

Abstract

We provide an electric valve that enables high-precision flow control regardless of variations in component dimensions. [Solution] An electric valve in one embodiment comprises a locking member 146 externally fitted onto an operating rod 32, a connecting member 142 that connects the operating rod 32 and the valve body 34, and a stopper mechanism that restricts the displacement of the operating rod 32 in the valve closing direction. The locking member 146 has a first end face and a second end face in the axial direction. The connecting member 142 has a locking surface that faces the second end face in the axial direction. When the valve is opened, the operating rod 32 and the valve body 34 are connected by the second end face contacting the locking surface. When the valve is closed, the connection is released by the second end face moving away from the locking surface. A clearance is formed between the locking surface and the second end face when the stopper mechanism is functioning. This clearance is set by fixing the operating rod 32 and the locking member 146 with fixing means that can adjust their relative axial position.

Description

Technical Field

[0001] The present invention relates to an electric valve, and particularly to the structure of a stopper that functions during the valve closing operation.

Background Art

[0002] An automotive air conditioner is generally configured by arranging a compressor, an external heat exchanger, an expansion device, an evaporator, etc. in a refrigeration cycle. In the refrigeration cycle, various control valves are provided to control the flow of the refrigerant, such as an expansion valve as the expansion device. With the spread of recent electric vehicles and the like, an electric valve equipped with a motor (stepping motor) as a drive unit has been widely adopted.

[0003] In such an electric valve, a shaft is connected to the rotor of the motor, and a valve body is provided at the tip of the shaft (see Patent Document 1). The rotational movement of the rotor is converted into the translational movement of the shaft by a screw feed mechanism, and thereby the valve body is driven in the opening and closing direction of the valve portion. A reference position serving as a control reference is set on the shaft. After the rotor continues to rotate in the valve closing direction and the valve body seats on the valve seat, and then further rotates a minute amount to reach a reference position also called the "operating origin", the rotation of the rotor is restricted by a stopper mechanism.

[0004] As such an electric valve, in addition to a rotational type stopper mechanism as in Patent Document 1, there is also one that adopts a so-called direct-acting type stopper mechanism that locks the shaft in the axial direction to restrict the rotation of the rotor (see Patent Document 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] For these electric valves, precise positional relationships between the seating point (where the valve body attaches to and detaches from the valve seat) and the aforementioned operating origin are necessary for control purposes. In other words, by accurately setting the correspondence between the amount of shaft movement based on the seating point and the operating origin, and the number of steps, which is the control command value, high accuracy in flow rate control during valve opening can be maintained.

[0007] However, there is considerable variation in dimensional accuracy in the parts related to the positional relationship between the seating point and the operating origin. This variation affects the positional accuracy of the seating point and the operating origin, and consequently the accuracy of flow control, so there was room for improvement.

[0008] One of the objectives of the present invention is to provide an electric valve that can achieve highly accurate flow control regardless of variations in component dimensions. [Means for solving the problem]

[0009] An electric valve according to one aspect of the present invention comprises a body having a fluid passage and a valve seat provided thereon; a valve element that attaches to and detaches from the valve seat to open and close the fluid passage; an operating rod provided coaxially with the valve element and rotationally driven by a rotor; a screw feed mechanism that converts the rotational motion of the rotor into axial motion of the operating rod; an annular locking member coaxially fitted to the tip of the operating rod; a connecting member assembled to the valve element, through which the operating rod is inserted coaxially, and which actsually connects the operating rod and the valve element via the locking member; and a stopper mechanism that restricts the displacement of the operating rod in the valve closing direction. The locking member has a first end face axially opposite to the end face of the valve element and a second end face opposite to the first end face. The connecting member has a locking surface axially opposite to the second end face. When the valve is opened, the second end face contacts the locking surface, thereby actingually connecting the operating rod and the valve element. When the valve is closed, the operating rod is displaced toward the valve body, and the second end face separates from the locking surface, thereby releasing the operating connection. When the stopper mechanism is functioning, a preset clearance is formed between the locking surface and the second end face. The clearance is set by fixing the operating rod and the locking member with a fixing means that allows adjustment of their relative axial position. The stroke of the operating rod from the seating point where the valve body attaches to and detaches from the valve seat to the operating origin where the stopper mechanism functions is determined by the above clearance.

[0010] In this embodiment, the relative axial position of the operating rod and the locking member is adjusted and fixed by the fixing means so that a preset clearance (set clearance) is formed between the locking member and the connecting member when the stopper mechanism is functioning. By precisely adjusting this clearance, the distance between the operating origin and the seating point can be precisely set, and the valve opening can be precisely controlled. As a result, the accuracy of flow control by the electric valve is improved.

[0011] An electric valve according to another aspect of the present invention comprises a body having a fluid passage and a valve seat provided thereon; a valve body that is detachable from the valve seat to open and close the fluid passage; an operating rod provided coaxially with the valve body and rotationally driven by a rotor; a screw feed mechanism that converts the rotational motion of the rotor into axial motion of the operating rod; a connecting member assembled to the valve body, through which the operating rod is inserted coaxially, and which acts as an operating connection between the operating rod and the valve body; and a stopper mechanism that restricts the displacement of the operating rod in the closing direction. A locking portion is provided at the tip of the operating rod, projecting radially outward. The connecting member has a locking surface axially opposite to the end face of the valve body, while forming a housing space between itself and the valve body to accommodate the locking portion. A spacer is placed in the housing space. When the valve is opened, the locking portion and the locking surface are connected, thereby acting as an operating connection between the operating rod and the valve body. When the valve is closed, the connection between the locking portion and the locking surface is released, thereby releasing the operating connection between the operating rod and the valve body. When the stopper mechanism is functioning, a clearance, which is an axial space, is formed between the locking part and the locking surface. The clearance is set by the thickness of the spacer. The stroke of the operating rod from the seating point where the valve body attaches to and detaches from the valve seat to the operating origin where the stopper mechanism functions is determined by the above clearance.

[0012] In this embodiment, the thickness of the spacer is set (selected) so that a set clearance is formed between the locking part and the connecting member when the stopper mechanism is functioning. By precisely adjusting this clearance, the distance between the operating origin and the seating point can be precisely set, thereby improving the accuracy of flow control.

[0013] An electric valve according to yet another aspect of the present invention comprises a body having a fluid passage and a valve seat provided thereon; a valve element that is detachably attached to the valve seat to open and close the fluid passage; an operating rod provided coaxially with the valve element and rotationally driven by a rotor; a screw feed mechanism that converts the rotational motion of the rotor into axial motion of the operating rod; a connecting member assembled to the valve element, through which the operating rod is inserted coaxially, and which acts as a connection between the operating rod and the valve element; a guide member fixed to the body and through which the operating rod is inserted coaxially; and an engaging portion outside the guide member that displaces integrally with the operating rod. A locking portion is provided at the tip of the operating rod, projecting radially outward. The locking portion has a first end face axially opposite to the end face of the valve element and a second end face opposite to the first end face. The connecting member has a locking surface axially opposite to the second end face. When the valve is opened, the second end face contacts the locking surface, thereby acting as a connection between the operating rod and the valve element. During valve closing, the operating rod is displaced toward the valve body, and the second end face separates from the locking surface, releasing the operating connection. As the operating rod is displaced in the valve closing direction, the engaging portion is locked to the guide member, activating a stopper mechanism that restricts the displacement of the operating rod in the valve closing direction. When the stopper mechanism is functioning, a preset clearance is formed between the locking surface and the second end face. With the position for locking the engaging portion fixed on the guide member, the clearance is set by fixing the operating rod and the engaging portion with a fixing means that allows adjustment of the relative position in at least one of the axial and rotational directions. The stroke of the operating rod from the seating point where the valve body attaches to and detaches from the valve seat to the operating origin where the stopper mechanism functions is determined by the clearance.

[0014] In this embodiment, the operating rod and the engaging portion are adjusted and fixed in a relative position in at least one of the axial and rotational directions such that a set clearance is formed between the locking portion and the connecting member when the stopper mechanism is functioning. By precisely adjusting this clearance, the distance between the operating origin and the seating point can be precisely set, thereby improving the accuracy of flow control.

[0015] An electric valve according to yet another aspect of the present invention comprises a body having a fluid passage and a valve seat provided thereon; a valve element that is detachably attached to the valve seat to open and close the fluid passage; an operating rod provided coaxially with the valve element and rotationally driven by a rotor; a screw feed mechanism that converts the rotational motion of the rotor into axial motion of the operating rod; a connecting member assembled to the valve element, through which the operating rod is inserted coaxially, and which acts as an operating connection between the operating rod and the valve element; a guide member fixed to the body and through which the operating rod is inserted coaxially; an engaging member assembled to the guide member; and an engaging portion that is displaced integrally with the operating rod outside the guide member. A locking portion is provided at the tip of the operating rod, projecting radially outward. The locking portion has a first end face axially opposite to the end face of the valve element and a second end face opposite to the first end face. The connecting member has a locking surface axially opposite to the second end face. When the valve is opened, the second end face contacts the locking surface, thereby connecting the operating rod and the valve body. When the valve is closed, the operating rod is displaced toward the valve body, and the second end face separates from the locking surface, releasing the operating connection. As the operating rod is displaced in the valve-closing direction, the engaging portion is locked to the engaging member, activating a stopper mechanism that restricts the displacement of the operating rod in the valve-closing direction. When the stopper mechanism is functioning, a preset clearance is formed between the locking surface and the second end face. With the position of the engaging portion relative to the operating rod fixed, the clearance is set by fixing the guide member and the engaging member with a fixing means that allows adjustment of the relative position in at least one of the axial and rotational directions. The stroke of the operating rod from the seating point where the valve body attaches to and detaches from the valve seat to the operating origin where the stopper mechanism functions is determined by the clearance.

[0016] In this embodiment, the guide member and the engaging member are adjusted and fixed in a relative position in at least one of the axial and rotational directions such that a set clearance is formed between the locking portion and the connecting member when the stopper mechanism is functioning. By precisely adjusting this clearance, the distance between the operating origin and the seating point can be precisely set, thereby improving the accuracy of flow control. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide an electric valve capable of achieving high-precision flow rate control regardless of variations in component dimensions.

Brief Description of the Drawings

[0018] [Figure 1] It is a cross-sectional view showing the structure of an electric valve according to the first embodiment. [Figure 2] It is an enlarged view of part A in FIG. 1. [Figure 3] It is a diagram showing the structure of the connecting portion between the valve body and the operating rod. [Figure 4] It is a diagram showing the state in which the stopper mechanism functions. [Figure 5] It is a partially enlarged view of the stopper mechanism. [Figure 6] It is a diagram showing an example of torque reduction control during valve closing operation. [Figure 7] It is a diagram showing the basic characteristics of a stepping motor. [Figure 8] It is a cross-sectional view showing the stopper mechanism according to a modified example. [Figure 9] It is a cross-sectional view showing the stopper mechanism according to another modified example. [Figure 10] It is a cross-sectional view showing the stopper mechanism according to another modified example. [Figure 11] It is a cross-sectional view showing the stopper mechanism according to another modified example. [Figure 12] It is a partial cross-sectional view showing the structure of an electric valve according to the second embodiment. [Figure 13] It is a diagram showing an example of a method for adjusting the clearance. [[ID=?]] [Figure 14] It is a cross-sectional view showing the stopper mechanism according to a modified example. [Figure 15] It is a diagram showing the structure of an electric valve according to the third embodiment. [Figure 16] It is a diagram showing an example of a method for adjusting the clearance. [[ID=?]] [Figure 17] It is a diagram showing a method for adjusting the clearance according to a modified example. [[ID=??]] [Figure 18] It is a diagram showing a method for adjusting the clearance according to another modified example. There seem to be some tags with incorrect numbering in the original text (e.g., , , [Figure 18] which might be causing issues in the translation. I've translated as accurately as possible while keeping those tags as they are). If you can correct the original text regarding those tags, it would be better for a more seamless translation. [Figure 19] This diagram illustrates a method for adjusting the clearance in relation to other modified examples. [Modes for carrying out the invention]

[0019] Embodiments of the present invention will be described in detail below with reference to the drawings. For convenience, the positional relationships of each structure may be expressed based on the illustrated state in the following description. In addition, substantially identical components in the following embodiments and their modifications will be denoted by the same reference numerals, and their descriptions will be omitted as appropriate.

[0020] [First Embodiment] Figure 1 is a cross-sectional view showing the structure of an electric valve according to the first embodiment. The electric valve 1 is applied to the refrigeration cycle of an automotive air conditioning system (not shown). This refrigeration cycle includes a compressor for compressing circulating refrigerant, a condenser for condensing the compressed refrigerant, an expansion valve for throttling and expanding the condensed refrigerant and sending it out as a mist, and an evaporator for evaporating the mist refrigerant and cooling the air in the vehicle cabin with its latent heat of vaporization. The electric valve 1 can function as this expansion valve.

[0021] The electric valve 1 is constructed by assembling a valve unit 100 and a passage body 200. The valve unit 100 includes a rotor unit 90 and a stator unit 92 as drive units. The rotor unit 90 and the stator unit 92 are each fixed to the passage body 200. The stator unit 92 is fixed to the passage body 200 via a connecting member 101. The connecting member 101 includes a metal plate fixed to the stator unit 92 and a screw for fixing the metal plate to the passage body 200.

[0022] The passage body 200 is made of a metal such as an aluminum alloy and has a roughly rectangular prism shape. An inlet port 202 and an outlet port 204 are provided on the side of the passage body 200. Piping extending from the condenser side is connected to the inlet port 202, and piping leading to the evaporator inlet is connected to the outlet port 204.

[0023] A fluid passage 210 is formed in the passage body 200, connecting the inlet port 202 and the outlet port 204. The passage body 200 encloses the valve portion of the valve unit 100 midway through the fluid passage 210. A mounting hole 216 opens upward at the top of the passage body 200. The mounting hole 216 communicates with the fluid passage 210. A step is provided slightly below the opening end of the mounting hole 216, and a female thread 218 is formed in this step.

[0024] The valve unit 100 is constructed by coaxially assembling a rotor unit 90 and a stator unit 92. The rotor unit 90 and the stator unit 92 are not directly fixed to each other, but are indirectly fixed by each being fixed to the passage body 200. The rotor unit 90 has a valve body 5 that encloses the valve section. In this embodiment, the valve body 5 corresponds to the "body" of the present invention.

[0025] The valve body 5 is constructed by coaxially assembling a guide member 6, a valve housing 7, and a valve seat member 8. The guide member 6 is cylindrical, and an internal thread 40 is formed on its upper inner surface. The valve seat member 8 is stepped cylindrical, and a valve seat 24 is formed on its lower part. The upper end of the valve seat member 8 is press-fitted into the lower end of the guide member 6. A seal ring 20 (O-ring) is fitted to the lower outer surface of the valve seat member 8.

[0026] An inlet port 26 is provided on the side of the valve seat member 8, and an outlet port 28 is provided at the bottom of the valve seat member 8. The inlet port 26 communicates with the introduction port 202, and the outlet port 28 communicates with the outlet port 204. A valve chamber 30 is formed inside the valve seat member 8. The inlet port 26 and the outlet port 28 communicate via the valve chamber 30 to form an internal passage of the valve body 5, and this internal passage constitutes part of the fluid passage 210.

[0027] The valve housing 7 is a cylindrical press-formed product and is assembled to cover the connection between the guide member 6 and the valve seat member 8 from the outside. A male thread 10 that can be screwed into a female thread 218 is formed on the lower outer circumference of the valve housing 7. When assembling the valve unit 100 to the passage body 200, the valve body 5 is inserted into the mounting hole 216. The male thread 10 and the female thread 218 are screwed together to fasten the valve body 5 to the passage body 200.

[0028] An annular seal housing portion 222 (annular groove) is provided on the upper surface of the passage body 200, surrounding the mounting hole 216, and a seal ring 220 (O-ring) is fitted into it. When the valve body 5 is fastened to the passage body 200, the seal ring 220 is interposed between the upper surface of the passage body 200 and the valve body 5. The seal ring 220 restricts the leakage of refrigerant from the inside to the outside of the passage body 200. The seal ring 20 seals the space between the upstream passage 230 and the downstream passage 232 of the valve section.

[0029] An operating rod 32 extending from the rotor 60 of the rotor unit 90 is inserted inside the valve body 5. A valve body 34 is detachably connected to the lower end of the operating rod 32 (details will be described later). The valve body 34 attaches to and detaches from the valve seat 24 from the valve chamber 30 side to open and close the valve and, consequently, the fluid passage 210. The operating rod 32 is obtained by machining a rod made of a non-magnetic metal, and a male thread 38 is formed on the outer circumferential surface of its axial center. The male thread 38 meshes with the female thread 40 of the guide member 6. Through the screw feeding mechanism 109 of these threaded parts, the rotational motion of the rotor 60 is converted into axial motion of the operating rod 32. The operating rod 32 is rotationally driven by the rotor 60 and displaced in the axial direction. As a result, the valve body 34 moves (up and down) in the axial direction, that is, in the opening and closing direction of the valve.

[0030] The rotor 60 of the rotor unit 90 and the stator 64 of the stator unit 92 constitute a two-phase stepping motor. The rotor unit 90 has a bottomed cylindrical can 66, and the rotor 60 is positioned inside the can 66. The stator 64 is positioned outside the can 66. The can 66 is a component that covers the space in which the valve body 34 and its drive mechanism are positioned and encloses the rotor 60, defining an inner pressure space (internal space) where the refrigerant pressure acts and an outer non-pressure space (external space) where it does not act.

[0031] In this embodiment, the can 66 is made of stainless steel (hereinafter referred to as "SUS"), which is a non-magnetic metal, and its lower end is fitted into the upper end of the valve housing 7. The valve body 5 and the can 66 are fixed together by welding (circumferential welding) along the boundary between the can 66 and the valve housing 7 (not shown), and airtightness (seal) between them is ensured. The above-mentioned pressure space is formed between the can 66 and the valve housing 7.

[0032] The stator 64 is constructed by assembling a bobbin 70 around which a coil 68 is wound onto a yoke 72 having multiple pole teeth. The stator 64 is housed in a case 76. The case 76 is obtained by injection molding of a corrosion-resistant resin material. The stator unit 92 has a hollow structure, and the stator 64 is assembled to the rotor unit 90 with the can 66 coaxially inserted through it. The weld between the can 66 and the valve body 5 is located inside the case 76.

[0033] The rotor 60 comprises a disc-shaped end member 102 attached to the operating rod 32 and a rotor magnet 104 attached to the outer circumferential surface of the end member 102. The rotor magnet 104 is cylindrical and magnetized (applied magnets) to multiple poles in its circumferential direction. The end member 102 is coaxially fixed to the upper part of the operating rod 32. A relatively large annular space S1 is formed between the inner circumferential surface of the rotor magnet 104 and the outer circumferential surface of the guide member 6. The operating rod 32 passes through the end member 102 and extends upward above the rotor 60.

[0034] The stator unit 92 has a circuit board 118 on the outside of the can 66. The circuit board 118 is fixed inside the case 76. Various circuits that function as control and communication units are mounted on the underside of the circuit board 118. Specifically, a drive circuit for driving the motor, a control circuit (microcomputer) that outputs control signals to the drive circuit, a communication circuit for the control circuit to communicate with external devices, and a power supply circuit for supplying power to each circuit and the motor (coil) are mounted. The upper end of the case 76 is closed by a resin cover 77. The circuit board 118 is arranged in the space below the cover 77 in the case 76.

[0035] A seal ring 21 (O-ring) is interposed between the inner circumferential surface of the lower end of case 76 and the outer circumferential surface of the lower end of can 66. This prevents moisture from entering the stator unit 92 from the outside.

[0036] A terminal 69 extends from the bobbin 70 and connects to the coil 68, and is connected to the circuit board 118. Power lines, ground lines, and communication lines are formed on the circuit board 118, and terminal elements 120 are connected to them. The terminal elements 120 are constructed by resin-molding power terminals connected to the power lines, ground terminals connected to the ground lines, and communication terminals connected to the communication lines (collectively referred to as "connection terminals 122") into their main body. A connector section 124 is integrally provided on the side of the case 76, and the terminal elements 120 are assembled inside the connector section 124.

[0037] When assembling the stator unit 92, the terminal element 120 is assembled by inserting it into the connector portion 124 from the inside of the case 76, and then the stator 64 is housed in the case 76. After that, the retaining member 119 is inserted into the case 76 from above the stator 64 and fixed in place. The retaining member 119 is made of a plate material with an L-shaped cross-section and supports the stator 64 by pressing it from above, and also supports the terminal element 120 by pressing it from behind. The terminal 69 passes through the retaining member 119 in the vertical direction. Then, the circuit board 118 is inserted from above the case 76 and fixed in place while connecting it to the terminal 69 and the connection terminal 122. The upper end opening of the case 76 is closed with the cover 77.

[0038] Figure 2 is an enlarged view of section A in Figure 1. The guide member 6 is made of a metal with excellent machinability, such as brass, and the valve seat member 8 is made of a metal with excellent wear resistance, such as stainless steel. The guide member 6 has a stepped cylindrical shape, with its inner diameter decreasing at the top and its outer diameter decreasing slightly at the bottom. A female thread 40 is formed on the inner circumferential surface of its upper part. Its lower part is press-fitted into the valve housing 7. A communication hole 128 is provided on the side of the guide member 6 to connect the inside and outside.

[0039] The inner diameter of the lower end of the guide member 6 is slightly enlarged, and the upper end of the valve seat member 8 is press-fitted into it. A flange portion 130 projecting radially outward is provided on the upper outer circumferential surface of the valve seat member 8. The outer diameter of the flange portion 130 is slightly smaller than the outer diameter of the lower end of the guide member 6. The upper surface of this flange portion 130 is locked to the lower surface of the guide member 6, thereby restricting the amount of press-fitting of the valve seat member 8.

[0040] On the other hand, a flange portion 132 is provided at the lower end of the valve housing 7, projecting radially inward. The inner diameter of the flange portion 132 is larger than the outer diameter of the portion of the valve seat member 8 below the flange portion 130, and smaller than the outer diameter of the flange portion 130. The lower surface of the flange portion 130 is locked to the upper surface of the flange portion 132, thereby supporting the valve seat member 8 from below. The amount of press-fitting of the guide member 6 into the valve housing 7 is also restricted. The valve seat member 8 is supported axially in such a manner that the flange portion 130 is sandwiched vertically between the guide member 6 and the valve housing 7, thus preventing it from falling out of the valve body 5.

[0041] In this configuration of the valve body 5, the press-fit portion 134 of the guide member 6 is located in the upper half of the valve housing 7, and the male thread 10 is located in the lower half of the valve housing 7. That is, the press-fit portion 134 is located above the male thread 10 and is offset axially from its threaded portion. This prevents the valve housing 7 from expanding radially at the position of the threaded portion during the press-fitting process, ensuring that there is no interference with the screwing of the male thread 10 and the female thread 218.

[0042] The valve housing 7 has a flange portion 136 extending radially outward from its upper end. An annular step 138 is formed on the outer peripheral edge of the upper surface of the flange portion 136. The can 66 is assembled coaxially with the valve body 5 by fitting its lower end opening into the step 138. Full-circumference welding is performed along the boundary between the can 66 and the flange portion 136. To ensure weldability between the two, the can 66 and the valve housing 7 are made of the same type of metal.

[0043] The valve seat member 8 is a bottomed cylindrical shape, with a valve hole 22 and a valve seat 24 formed at its lower part. The inlet port 26 is formed on the side surface of the cylindrical portion of the valve seat member 8. The pressure of the fluid introduced into the valve chamber 30 through the inlet port 26 is also guided to the internal space of the can 66 through the communication hole 128.

[0044] The valve body 34 has a stepped cylindrical shape, and the tapered surface formed on its lower half is the attachment / detachment surface 34a for attaching to and detaching from the valve seat 24. A flange portion 140 projecting radially outward is provided on the outer circumferential surface of the upper half of the valve body 34. A connecting member 142 for operating connection with the operating rod 32 is assembled to the upper part of the valve body 34.

[0045] The connecting member 142 is a cylindrical member that is coaxially assembled and fixed to the valve body 34. The upper part of the valve body 34 is press-fitted into the lower part of the connecting member 142. The amount of press-fitting is restricted by the upper surface of the flange portion 140 being locked to the lower surface of the connecting member 142. The upper end of the connecting member 142 is reduced in diameter to form a guide portion 144. The lower part of the operating rod 32 slides through the guide portion 144.

[0046] An annular locking member 146 is coaxially fitted and fixed to the tip of the operating rod 32. The locking member 146 functions as a "locking portion" that protrudes radially from the side surface of the operating rod 32. The locking member 146 is press-fitted into the tip of the operating rod 32 and housed in a housing space S2 surrounded by the valve body 34 and the connecting member 142. The connecting member 142 is slidably supported on the operating rod 32. In this embodiment, the connecting member 142 slides relative to the operating rod 32 at the position of the guide portion 144, but it may also be configured to slide relative to the locking member 146.

[0047] A spring 148 (biasing member) is interposed between the connecting member 142 and the guide member 6 to bias the valve body 34 in the closing direction. The biasing force of the spring 148 is transmitted to the valve body 34 via the connecting member 142. When the valve is opened, the locking member 146 contacts and pushes up against the bottom surface (locking surface) of the connecting member 142, causing the valve body 34 to move in the opening direction.

[0048] The upper part of the operating rod 32 is provided with a notch 150 (a so-called H-cut structure) having a pair of surfaces parallel to the axis. On the other hand, the central part of the end member 102 is provided with an insertion hole 152 that is complementary in shape to the notch 150. A circular boss-shaped guide portion 154 is provided protruding from the center of the lower surface of the end member 102. The upper part of the operating rod 32 is press-fitted into the guide portion 154, and the notch 150 is inserted through the insertion hole 152.

[0049] This press-fit structure prevents the operating rod 32 from separating from the end member 102. Furthermore, the fitting structure between the notch 150 and the insertion hole 152 restricts the rotation of the operating rod 32 relative to the rotor 60. The operating rod 32 functions as the rotation axis of the rotor 60 and rotates integrally with the rotor 60. Note that a D-cut structure or other anti-rotation structure may be used instead of the H-cut structure.

[0050] Figure 3 shows the structure of the connection between the valve body 34 and the operating rod 32. The upper bottom surface of the connecting member 142 forms a locking surface 160. The locking surface 160 faces the locking member 146 axially from the opposite side of the valve body 34. In the open state, the tip surface of the operating rod 32 is separated from the upper end surface 162 of the valve body 34, and the locking member 146 contacts the locking surface 160. On the other hand, in the closed state, the locking member 146 is separated from the locking surface 160. The rotation of the rotor 60 is restricted by the tip surface of the operating rod 32 contacting the upper end surface 162 of the valve body 34. In other words, the tip surface of the operating rod 32 and the upper end surface 162 of the valve body 34 constitute a "stopper mechanism" that restricts the displacement of the operating rod 32 in the valve closing direction.

[0051] In this case, the tip surface of the operating rod 32 abuts against the upper end surface 162 of the valve body 34 on its central axis L. In this embodiment, the tip surface of the operating rod 32 has a curved surface that moves further away from the upper end surface 162 of the valve body 34 as it moves away from the central axis L. Specifically, since the tip of the operating rod 32 is spherical, the operating rod 32 and the valve body 34 abut in a point contact manner.

[0052] The locking member 146 has a lower surface 146a and an upper surface 146b located at a distance from the central axis L. The lower surface 146a corresponds to the "first end surface" and faces the upper end surface 162 of the valve body 34 in the axial direction. The upper surface 146b corresponds to the "second end surface" and faces the locking surface 160 in the axial direction. As shown in the figure, the operating rod 32 protrudes downward from the lower surface 146a of the locking member 146. By adjusting the amount P of protrusion of this operating rod 32, the axial clearance CL between the locking member 146 and the connecting member 142 at the operating origin (reference position) is set.

[0053] This clearance CL corresponds to the number of drive steps from when the electric valve 1 starts closing at the seating point until it reaches the operating origin (reference position), that is, from when the valve body 34 seats on the valve seat 24 until the rotation of the rotor 60 is restricted. More specifically, the sum of the clearance CL and the backlash of the threaded portion corresponds to that number of drive steps.

[0054] More specifically, as shown in the figure, if A is the height of the accommodating space S2 in the connecting member 142 (i.e., the distance between the locking surface 160 and the bottom surface of the connecting member 142), B is the insertion height of the valve body 34 into the connecting member 142 (i.e., the height from the top surface of the flange portion 140 to the upper end surface 162 of the valve body 34), and C is the axial length of the locking member 146, then the clearance CL is expressed by the following formula (1). CL = ABCP …(1)

[0055] Therefore, even if there are variations in the dimensions of any of the valve body 34, connecting member 142, or locking member 146, the clearance CL can be adjusted to a preset value (also called the "set clearance") by measuring the dimensions of these parts and then adjusting the protrusion amount P of the operating rod 32.

[0056] Returning to Figure 1, the electric valve 1 configured as described above functions as an electric expansion valve whose valve opening degree can be adjusted by drive control of the rotor unit 90. Based on a command from an external device (not shown), the control unit sets a control amount (number of motor drive steps) to achieve the target opening degree and outputs a drive signal to the drive circuit to achieve this. The drive circuit supplies two-phase drive current (drive pulse) to each coil 68 at the set timing. As a result, the rotor 60 rotates with high resolution. At this time, if the valve body 34 is in an open state separated from the valve seat 24, the locking member 146 comes into contact with the connecting member 142 due to the biasing force of the spring 148, and the operating rod 32 and thus the valve body 34 operate together with the rotor 60 (see Figure 4(B)).

[0057] The rotor 60 moves vertically by the screw feed mechanism 109. The valve body 34 translates in the opening and closing direction of the valve, and the opening degree of the valve is adjusted to the set opening degree. The screw feed mechanism 109 converts the rotational motion of the rotor 60 around its axis into axial motion (linear motion) of the actuating rod 32, driving the valve body 34 in the opening and closing direction of the valve. When the electric valve 1 functions as an expansion valve, the valve is controlled to a small opening degree.

[0058] Figure 4 shows the stopper mechanism in a functional state. Figure 4(A) shows the valve closed state, and Figure 4(B) shows the valve fully open state. Figure 5 is a magnified view of a part of the stopper mechanism. Figure 5(A) is a magnified view of part B of Figure 4(A), and Figure 5(B) is a magnified view of part C of Figure 4(B).

[0059] As shown in Figure 4(A), when the valve is closed, after the valve body 34 seats on the valve seat 24, the operating rod 32 is displaced relative to the connecting member 142 toward the valve body 34, and the locking member 146 separates from the locking surface 160. This releases the operating connection between the operating rod 32 and the valve body 34. Then, when the rotor 60 reaches the operating origin (reference position), the tip surface of the operating rod 32 comes into contact with the upper end surface 162 of the valve body 34, as shown in the figure, thereby restricting the rotation of the rotor 60.

[0060] In this case, as shown in Figure 5(A), the tip surface of the operating rod 32 abuts against the upper end surface 162 of the valve body 34 on its central axis L. Because the tip of the operating rod 32 is spherical, the operating rod 32 and the valve body 34 abut in a point contact manner. Therefore, the outer diameter of the contact surface between the operating rod 32 and the valve body 34 can be reduced, and frictional torque can be reduced.

[0061] On the other hand, as shown in Figure 4(B), when the valve is opened, the tip surface of the operating rod 32 separates from the upper end surface 162 of the valve body 34, and the locking member 146 contacts the locking surface 160, thereby connecting the operating rod 32 and the valve body 34. As the rotor 60 rotates, the operating rod 32 and the valve body 34 are displaced together. When fully open, the rear end surface (upper end surface) of the operating rod 32 contacts the upper bottom surface 164 of the can 66 on its central axis L.

[0062] As shown in Figure 5(B), the rear end surface of the operating rod 32 is also spherical, so the operating rod 32 and the cann 66 come into contact at a point. This allows the outer diameter of the contact surface between the operating rod 32 and the cann 66 to be reduced, thereby reducing frictional torque.

[0063] Next, we will explain the torque reduction control performed when the valve is closed. In this embodiment, as described above, the operating rod 32 is fixed to the rotor 60. Therefore, unlike the structure of Patent Document 1, the axial thrust force from the screw feed mechanism 109 is directly transmitted to the valve body 34 via the operating rod 32. As a result, there is a tendency for friction torque to increase. Therefore, in addition to reducing friction torque by the stopper mechanism described above, the increase in friction torque is further suppressed by reducing the driving torque of the stepping motor (also simply called "motor") from a predetermined timing when the valve body 34 is closed.

[0064] Figure 6 shows an example of torque reduction control during valve closing operation. Figure 6(A) is a timing chart representing torque reduction control, and Figure 6(B) is an enlarged view of section A in Figure 6(A). The horizontal axis in the figure shows the passage of time from the start of valve opening to the closed state. The vertical axis shows the drive step from the operating origin (solid line), the flow rate of refrigerant flowing through the valve (dotted line), the value of the current supplied to the motor (magnitude of current: dotted line), and the drive frequency (pulse frequency: dashed line). Figure 7 shows the basic characteristics of a stepping motor (relationship between rotor rotation speed and drive torque). The horizontal axis in the figure shows rotation speed, and the vertical axis shows drive torque.

[0065] As shown in Figure 6(A), the control unit drives and controls the motor based on this operating origin, thereby controlling the position of the valve body 34 (i.e., the valve opening). The control unit pre-stores the motor drive steps from the operating origin to the seating point, and sequentially stores and updates the current drive steps when controlling the motor. In particular, when the valve body 34 closes, the motor drive torque is reduced when the drive steps reach a predetermined torque switching step. Torque reduction is achieved by lowering the supply current value and increasing the drive frequency. By increasing the motor drive frequency, the rotational speed can be increased and the torque can be reduced.

[0066] Here, it is generally known that stepping motors have the basic characteristics shown in Figure 7 between rotor rotation speed and drive torque. When the rotor rotation speed is increased, the torque peaks (maximum torque Tp) at a certain rotation speed, and as the rotation speed is further increased, the drive torque decreases gradually.

[0067] In this embodiment, regarding the control of the electric valve 1, the rotational speed range in which the maximum torque Tp or a nearby driving torque can be obtained is set as the "normal control range". Then, when the electric valve 1 opens, the motor drive frequency is set so that the rotational speed in the normal control range is obtained. In other words, by changing the rotational speed to be higher or lower than the normal control range, the motor drive torque can be reduced compared to the normal control state while operating the electric valve 1 in the closing direction. In this embodiment, the motor drive frequency is increased when the drive step reaches the torque switching step, thereby increasing the rotor rotational speed above the normal control range and achieving the torque reduction described above.

[0068] As shown in Figure 6(B), in this embodiment, the torque switching step is set to a predetermined step before the reference step corresponding to the seating point when viewed in the valve closing direction. As a result, the torque is reduced almost simultaneously with the valve body 34 beginning to seat on the valve seat 24. This reduces the surface pressure generated between the valve body 34 and the valve seat 24 after seating.

[0069] The control unit outputs a control command as the number of steps (drive steps) from the operating origin when controlling the valve opening.

[0070] In this embodiment, as shown in Figure 2, a spring 148 is provided to bias the valve body 34 in the closing direction, and a differential pressure in the closing direction also acts on the valve body 34. Therefore, relatively high torque is required for opening the valve, but relatively low torque is sufficient for closing the valve. For this reason, even if such torque reduction is performed during closing the valve, it does not interfere with the closing operation.

[0071] As described above, in this embodiment, the axial relative position of the operating rod 32 and the locking member 146 is adjusted and fixed so that a preset clearance is formed between the locking member 146 and the connecting member 142 when the stopper mechanism is functioning. By precisely adjusting the clearance CL to the set clearance, the distance between the operating origin (stopper position) and the seating point (valve opening point) can be precisely set, and the valve opening degree can be precisely controlled. As a result, the accuracy of flow rate control by the electric valve is improved.

[0072] Furthermore, during valve closing operation, the tip surface of the operating rod 32 contacts the end surface of the valve body 34 at a point on the central axis L. This reduces the contact surface between the operating rod 32 and the valve body 34, thereby reducing the friction torque between them. Also, when fully open, the rear end surface of the operating rod 32 contacts the bottom surface of the cann 66 at a point on the central axis L. This reduces the contact surface between the operating rod 32 and the cann 66, thereby reducing the friction torque between them. In addition, the torque reduction control described above is also performed during valve closing operation. As a result, operation lock in the electric valve 1 can be prevented or suppressed.

[0073] [Differentiation] Figure 8 is a cross-sectional view showing a modified stopper mechanism. Figure 8(A) shows the connection structure between the operating rod and the valve body. Figure 8(B) is an enlarged view of part B in Figure 8(A), and Figure 8(C) is an enlarged view of part C in Figure 8(A). For convenience of explanation, can 66 is indicated in Figure 8(C).

[0074] As shown in Figure 8(A), in this modified example, flat surfaces are provided on the front and rear ends of the operating rod 310. As shown in Figure 8(B), the front end of the operating rod 310 has a curved surface 314 (spherical surface) that moves further away from the upper end surface 162 of the valve body 34 as it moves away from the central axis L, and a flat surface 312 that includes the central axis L and is perpendicular to the central axis L. The flat surface 312 is continuous with the curved surface 314 at its outer edge. The outer diameter of the flat surface 312 is sufficiently smaller than the outer diameter of the front end of the operating rod 310. When the valve is closed, the flat surface 312 contacts the upper end surface 162, thereby restricting the rotation of the rotor 60.

[0075] As shown in Figure 8(C), the rear end surface of the operating rod 310 also has a curved surface 316 (spherical surface) that moves further away from the upper bottom surface 164 of the can 66 as it moves away from the central axis L, and a flat surface 318 that includes the central axis L and is perpendicular to the central axis L. The flat surface 318 is continuous with the curved surface 316 at its outer edge. The outer diameter of the flat surface 318 is sufficiently smaller than the outer diameter of the rear end of the operating rod 310. When the valve is open (fully open), the flat surface 318 comes into contact with the upper bottom surface 164, thereby restricting the rotation of the rotor 60.

[0076] By making the end face of the operating rod 310, which functions as a stopper mechanism, a flat surface, wear on that end face can be suppressed. On the other hand, since both the flat surfaces 312 and 318 are formed by cutting a part of a spherical surface, the area can be kept small. Therefore, the friction torque generated when it functions as a stopper mechanism can be reduced, and operation lock can be prevented or suppressed.

[0077] Figure 9 is a cross-sectional view showing a stopper mechanism related to other modifications. Figures 9(A) to (C) show variations of the modifications. In the above embodiment, as shown in Figures 2 and 3, an example was given in which the tip surface of the operating rod 32 is spherical and the upper end surface 162 of the valve body 34 is flat. Furthermore, an example was given in which a cylindrical locking member 146 is press-fitted into the tip of the operating rod 32.

[0078] In the modified example, as shown in Figure 9(A), the tip surface 334 of the operating rod 330 may be a tapered surface instead of a spherical surface. This tapered surface also moves further away from the upper end surface 162 of the valve body 34 as it moves away from the central axis L. If the upper end surface 162 of the valve body 34 is a flat surface as shown in the figure, the tip surface of the operating rod only needs to have a convex shape that is convex toward the upper end surface of the valve body 34.

[0079] As shown in Figure 9(B), the tip surface 342 of the operating rod 340 may be a flat surface, and a protrusion 346 may be provided in the center of the upper end surface of the valve body 344. The protrusion 346 is formed in a curved (spherical) shape and is detachably in contact with the tip surface 342 of the operating rod 340 on the central axis L.

[0080] As shown in Figure 9(C), the valve body 360 and the connecting member 362 may be crimped together. The upper end of the valve body 360 is provided with a flange portion 364 that protrudes radially outward. On the other hand, the lower end of the connecting member 362 is enlarged in diameter, and the flange portion 364 is fitted into it. By crimping the lower end of the connecting member 362 inward, the valve body 360 and the connecting member 362 are fixed coaxially.

[0081] In other modifications, the protrusions on either the tip surface of the operating rod or the end surface of the valve body may be made stepped, and a flat surface may be provided at the tip of the upper step. By forming this flat surface to the minimum necessary size, the friction torque mentioned above can be reduced.

[0082] Figure 10 is a cross-sectional view showing a stopper mechanism relating to another modified example. In the above embodiment, a press-fit structure was adopted as a fixing means that could adjust the axial relative position between the operating rod 32 and the locking member 146. In this modified example, the operating rod 432 and the locking member 446 are fastened together by a screw structure as a fixing means. A male screw 434 is provided on the outer circumferential surface of the lower end of the operating rod 432. On the other hand, a female screw 448 is provided on the inner circumferential surface of the locking member 446. By adjusting the amount the locking member 446 is screwed into the operating rod 432, the amount P that the operating rod 432 protrudes from the lower surface of the locking member 446 can be adjusted. This makes it possible to set the size of the axial clearance CL between the locking member 446 and the connecting member 142 at the operating origin (reference position).

[0083] Figure 11 is a cross-sectional view showing a stopper mechanism relating to another modified example. In another modification, as shown in Figure 11(A), a disc-shaped locking member 534 is fixed to the tip of the operating rod 532, while a spacer 540 is placed between the tip surface of the operating rod 532 and the upper end surface of the valve body 34. The locking member 534 functions as a "locking part".

[0084] Specifically, an E-ring, which serves as a locking member 534, is fitted into an annular groove provided at the tip of the operating rod 532. In the closed state, as shown in the figure, the tip surface of the operating rod 532 comes into contact with the upper surface 542 of the spacer 540, thereby activating the stopper mechanism and restricting the displacement of the operating rod 532 in the valve closing direction. On the other hand, when the valve is opened, the tip surface of the operating rod 532 separates from the spacer 540, releasing the stopper mechanism, the locking member 534 comes into contact with the locking surface 160, and the valve body 34 and the operating rod 532 are connected in operation.

[0085] With this configuration, when the stopper mechanism is functioning, a clearance CL, which is an axial space, is formed between the locking surface 160 of the connecting member 142 and the upper surface 146b of the locking member 534. In other words, the thickness of the spacer 540 is set so that the clearance CL becomes the set clearance.

[0086] Here, if A is the height of the housing space S2 in the connecting member 142, B is the insertion height of the valve body 34 into the connecting member 142, C2 is the distance between the upper surface 146b of the locking member 534 and the tip surface (lower end surface) of the operating rod 532 (height from the lower end surface of the operating rod 532 to the upper surface 146b of the locking member 534), and T is the thickness of the spacer 540, then the clearance CL is expressed by the following formula (2). CL = AB - C2 - T …(2)

[0087] Therefore, after measuring these dimensions A, B, and C2, the thickness T required to obtain the set clearance CL is calculated from the above formula (2), and a spacer 540 having that thickness T is prepared (selected or machined) and assembled.

[0088] According to this modified example, even if there are variations in the dimensions of any of the valve body 34, connecting member 142, operating rod 532, or locking member 146 (such as machining errors compared to the design value), the clearance CL can be adjusted to the set clearance by measuring the dimensions of these parts and then setting the thickness T of the spacer 540. By accurately adjusting the clearance CL, the distance between the operating origin and the seating point can be accurately set.

[0089] In another modification, as shown in Figure 11(B), a locking portion 322 is integrally molded to the lower end of the operating rod 320. The locking portion 322 consists of an enlarged diameter portion provided at the lower end of the operating rod 320, with a protrusion 324 provided in the center of its lower surface. The protrusion 324 is formed in a curved (spherical) shape and constitutes the tip surface of the operating rod 320, and detachably contacts the upper end surface 162 (flat surface) of the valve body 34 on the central axis L.

[0090] On the other hand, an annular spacer 550 is positioned between the upper surface of the locking portion 322 and the locking surface 160. The spacer 550 is externally fitted onto the operating rod 320. With this configuration, when the valve is open, the locking portion 322 and the locking surface 160 are connected via the spacer 550. On the other hand, when the valve is closed and the stopper mechanism is functioning, a clearance CL is formed between the locking surface 160 of the connecting member 326 and the upper surface of the locking portion 322 (more precisely, between the locking surface 160 of the connecting member 326 and the upper surface of the spacer 550).

[0091] Here, if A3 is the height of the accommodating space S2 in the connecting member 326, B is the insertion height of the valve body 34 into the connecting member 142, C3 is the height of the locking portion 322, and T is the thickness of the spacer 550, then the clearance CL is expressed by the following formula (3). CL = A3 - B - C3 - T …(3)

[0092] Therefore, after measuring these dimensions A3, B, and C3, the thickness T required to obtain the set clearance CL is calculated from the above formula (3), and a spacer 550 having that thickness T is prepared (selected or machined) and assembled.

[0093] In this modified example, even if there are dimensional variations in any of the valve body 34, connecting member 326, operating rod 320, or locking part 322, the clearance CL can be adjusted to the set clearance by measuring their dimensions and then setting the thickness T of the spacer 550. By accurately adjusting the clearance CL, the distance between the operating origin and the seating point can be accurately set.

[0094] [Second Embodiment] Figure 12 is a partial cross-sectional view showing the structure of an electric valve according to the second embodiment. In this embodiment, a stopper mechanism is configured between the rotor 660 and the guide member 6. The rotor 660 has a rotor magnet 104 and an end member 602. The lower end surface of the end member 602 and the upper end surface of the guide member 6 function as a "stopper mechanism". The end member 602 has a guide portion 654 that is press-fitted onto the outer circumferential surface of the operating rod 32 and extends to the vicinity of the upper end surface of the guide member 6. The end member 602 functions as an "engaging portion" that displaces integrally with the operating rod 32. The locking member 146 functions as a "locking portion". The lower end surface of the guide portion 654 is locked onto the upper end surface of the guide member 6, thereby restricting the displacement of the operating rod 32 in the valve closing direction. Note that, in addition to press-fitting, screw structures, welding, and other fixing means can also be used to fix the end member 602 to the operating rod 32.

[0095] In this embodiment, the lower end surface of the end member 602, rather than the tip surface of the operating rod 32, functions as the stopper mechanism. Therefore, the tip surface of the operating rod 32 does not attach to or detach from the upper end surface of the valve body 34. In this configuration, the clearance CL is set by adjusting the axial relative position between the operating rod 32 and the guide portion 654 (end member 602).

[0096] Figure 13 shows an example of a method for adjusting the clearance CL. Figures 13(A) to (C) show the adjustment process. First, the end member 602 is temporarily pressed onto the operating rod 32, and the rotor 660 is temporarily assembled to the operating rod 32 (Figure 13(A)). At this time, the lower end surface of the guide portion 654 abuts against the upper end surface of the guide member 6. Here, the clearance CL = CL0 (clearance before adjustment) between the locking member 146 and the connecting member 142 in the closed valve state (operating origin) is assumed to be CL.

[0097] This pre-adjustment clearance CL0 is obtained by displacing the operating rod 32 in the valve opening direction and measuring the amount of displacement (movement height) from the operating origin to the seating point (valve opening point) (Figure 13(B)). At this time, a stroke sensor may be placed at the tip of the valve body 34, and it may be determined that the seating point has been reached when the start of the stroke of the valve body 34 is detected by the sensor. Alternatively, a sensor may be provided to detect the load torque acting on the operating rod 32 due to the load of the spring 148, and it may be determined that the seating point has been reached when the load torque is detected.

[0098] Next, the end member 602 is fully pressed into the operating rod 32 so that the clearance CL becomes the set clearance CLset (Figure 13(C)). That is, from the state of temporary pressing described above, the end member is fully pressed in by the difference between the clearance before adjustment CL0 and the set clearance CLset (CL0-CLset) as an adjustment value. This allows the clearance CL to be set to the set clearance CLset.

[0099] In this embodiment, the axial relative position of the operating rod 32 and the end member 602 (the press-fitting position of the guide portion 654 onto the operating rod 32) is adjusted and fixed so that a predetermined clearance CL is formed between the locking member 146 and the valve body 34 when the stopper mechanism is functioning. By accurately adjusting this clearance CL, the distance between the operating origin and the seating point can be precisely set, thereby improving the accuracy of flow rate control.

[0100] In this embodiment, since there is no particular need to adjust the position of the locking member 146 with respect to the operating rod 32, a "locking portion" that replaces the locking member 146 may be integrally molded at the tip of the operating rod 32.

[0101] [Differentiation] Figure 14 is a cross-sectional view showing a modified stopper mechanism. In this modified configuration, a locking member 754 is externally fitted onto the operating rod 32, separate from the end member 102 that supports the rotor magnet 104. The locking member 754 is annular in shape and is press-fitted onto the operating rod 32 so as to be positioned between the guide member 6 and the end member 102. The lower surface of the locking member 754 and the upper end surface of the guide member 6 function as a "stopper mechanism". The locking member 754 functions as an "engaging part" that displaces integrally with the operating rod 32.

[0102] Regarding the adjustment of the clearance CL in this modified example, the method of press-fitting the guide portion 654 onto the operating rod 32 in the second embodiment can be applied to the press-fitting of the locking member 754 onto the operating rod 32, so a detailed explanation is omitted.

[0103] In this modified example, a press-fit structure is used as the fixing means (structure that allows adjustment of the axial relative position between the operating rod 32 and the locking member 754), but a screw structure, welding, or other fixing means can also be used.

[0104] [Third Embodiment] Figure 15 is a diagram showing the structure of an electric valve according to the third embodiment. Figure 15(A) is a partial cross-sectional view. Figure 15(B) is a plan view showing the stopper mechanism as seen through the BB arrow in Figure 15(A). In this embodiment, a rotary stopper mechanism 810 is employed. As shown in Figure 15(A), the stopper mechanism 810 includes a first locking member 812 assembled to the guide member 6 and a second locking member 814 assembled to the operating rod 32. The stopper mechanism 810 is a rotary stopper that restricts the displacement of the operating rod 32 in the valve closing direction by the first locking member 812 locking the second locking member 814 in the rotational direction at the operating origin. The first locking member 812 functions as an "engaging member". The second locking member 814 functions as an "engaging member" that is rotationally driven by the rotor 60, and also functions as an "engaging part" that displaces integrally with the operating rod 32.

[0105] As shown in Figure 15(B), the first locking member 812 has a cylindrical body 820 and a flange portion 822 that protrudes radially inward from the upper end of the body 820, and is assembled to fit onto the upper end of the guide member 6. The body 820 is press-fitted coaxially onto the upper end of the guide member 6. The flange portion 822 catches on the upper surface of the guide member 6, thereby axially positioning the first locking member 812 with respect to the guide member 6. A locking portion 824 is provided at one point on the inner circumferential surface of the flange portion 822. The locking portion 824 has an L-shaped cross-section and extends radially inward and upward.

[0106] On the other hand, the second locking member 814 has an annular body 830 that is fitted onto the operating rod 32, and a locked portion 832 that protrudes radially outward from the outer edge of the body 830. The body 830 is press-fitted onto the upper part of the operating rod 32, and the second locking member 814 is displaced integrally with the operating rod 32. As shown in the figure, the two engage when the second locking member 814 is at a height position that overlaps with the first locking member 812. When the rotor 60 reaches the operating origin during valve closing operation, the locked portion 832 is locked in the rotational direction by the locking portion 824, thereby restricting the rotation of the operating rod 32 and, consequently, the rotor 60. At this time, the clearance CL becomes the set clearance.

[0107] Figure 16 shows an example of a method for adjusting the clearance CL. Figures 16(A) to (E) show the adjustment process. The lower part of each figure is a cross-sectional view showing the area around the stopper mechanism, and the upper part is a plan view showing the state of the stopper mechanism. First, the valve is closed by pressing the tip of the operating rod 32 against the valve body 34, and the second locking member 814 is press-fitted onto the operating rod 32 (Figure 16(A)). This fixes the position of the second locking member 814 relative to the operating rod 32. At this time, the second locking member 814 is brought close to the upper end surface of the guide member 6.

[0108] Here, the clearance CL = CL1 (pre-adjustment clearance) between the locking surface of the connecting member 142 and the locking member 146 in the closed valve state (operating origin) is defined as follows. This pre-adjustment clearance CL1 can be calculated in the same way as the clearance CL explained in relation to Figure 3. That is, it can be calculated by measuring the parameters A to C and P of the above equation (1) and substituting them into the same equation.

[0109] Next, the first locking member 812 is placed over the guide member 6 and aligned so that the locking portion 824 of the first locking member 812 and the locked portion 832 of the second locking member 814 engage. In other words, at this stage, the first locking member 812 is not press-fitted but is left rotatable, with the side surface of the locked portion 832 in contact with the side surface of the locking portion 824 (Figure 16(B)).

[0110] From this state, the first locking member 812 is rotated 360 degrees in one direction together with the second locking member 814, and the operating rod 32 is raised in the axial direction, resulting in a clearance CL = CL1 - p adjusted by the screw pitch p (Figure 16(C)). Rotating the first locking member 812 1 / 2 turn in one direction (180 degrees) adjusts it by 1 / 2 of the screw pitch p. In this way, the clearance can be adjusted to the set clearance based on the rotation angle of the first locking member 812 and the screw pitch p. After setting the set clearance, the first locking member 812 is press-fitted into the guide member 6 (Figure 16(D)), and then the rotor 60 (end member 102) is press-fitted into the operating rod 32 (Figure 16(E)).

[0111] In this embodiment, with the position of the second locking member 814 relative to the operating rod 32 (relative position in the rotational and axial directions) fixed, the rotational relative position of the guide member 6 and the first locking member 812 is adjusted. The clearance CL can be adjusted based on the rotation angle and screw pitch p of the first locking member 812. By accurately adjusting this clearance CL, the distance between the operating origin and the seating point can be precisely set, thereby improving the accuracy of flow control.

[0112] In this embodiment, a press-fit structure is used as the fixing means (structure that allows adjustment of the axial relative position between the operating rod 32 and the second locking member 814). Similarly, a press-fit structure is used as the fixing means (structure that allows adjustment of the axial relative position between the guide member 6 and the first locking member 812). In modified examples, screw structures, welding, or other fixing means may also be used for these fixing means.

[0113] [Differentiation] Figure 17 illustrates the method for adjusting the clearance CL in a modified example. Figures 17(A) to (E) show the adjustment process. The lower part of each figure is a cross-sectional view showing the area around the stopper mechanism, and the upper part is a plan view showing the state of the stopper mechanism. First, the valve is closed by pressing the tip of the operating rod 32 against the valve body 34, and the second locking member 814 is temporarily pressed into the operating rod 32. This temporarily fixes the position of the second locking member 814 relative to the operating rod 32. At this time, the second locking member 814 is brought close to the upper end surface of the guide member 6 (Figure 17(A)). In this closed valve state (operating origin), the clearance between the locking surface of the connecting member 142 and the upper surface of the locking member 146 is set to CL = CL1 (clearance before adjustment).

[0114] Next, the operating rod 32 is rotated in one direction together with the second locking member 814 to raise it to the seating point (valve opening point) where the locking surface of the connecting member 142 and the upper surface of the locking member 146 come into contact (Figure 17(B)). At this time, a stroke sensor may be placed at the tip of the valve body 34, and it may be determined that the seating point has been reached when the start of the stroke of the valve body 34 is detected by the sensor. Alternatively, a sensor may be provided to detect the load torque acting on the operating rod 32 due to the load of the spring 148, and it may be determined that the seating point has been reached when the load torque is detected.

[0115] Next, from this state, the operating rod 32 is rotated in the opposite direction together with the second locking member 814 to lower it by the set clearance CLset (Figure 17(C)). From this state, the first locking member 812 is press-fitted into the guide member 6 while aligning the locked portion 832 and the locking portion 824 (Figure 17(D)). The second locking member 814 is then fully press-fitted. At this time, the contact height between the locked portion 832 and the locking portion 824 is adjusted to an appropriate value. That is, while maintaining the minimum contact area necessary for the stopper mechanism to function in this state, the contact height is set so that when the second locking member 814 is rotated once in one direction, the locking portion 824 does not interfere with the locked portion 832. After that, the rotor 60 (end member 102) is press-fitted into the operating rod 32 (Figure 17(E)).

[0116] In this modified example, the position of the second locking member 814 with respect to the operating rod 32 (relative position in the rotational and axial directions) is fixed, and the relative position of the guide member 6 and the first locking member 812 in the rotational direction is adjusted.

[0117] Figure 18 shows a method for adjusting the clearance CL in relation to other modified examples. Figures 18(A) to (E) show the adjustment process. The lower part of each figure is a cross-sectional view showing the area around the stopper mechanism, and the upper part is a plan view showing the state of the stopper mechanism. When adjusting the clearance CL, first, the first locking member 812 is pressed into the guide member 6 to fix the position of the locking portion 824 on the guide member 6 (Figure 18(A)).

[0118] Next, the operating rod 32 is rotated in one direction to raise it until it reaches the seating point (valve opening point) where the locking surface of the connecting member 142 and the upper surface of the locking member 146 come into contact (Figure 18(B)). In this state, the second locking member 814 is attached to the operating rod 32 (Figure 18(C)). At this time, the rotational position (relative position) of the locked portion 832 relative to the operating rod 32 is adjusted, and then the second locking member 814 is pressed into the operating rod 32 to adjust the axial position (relative position) of the locked portion 832 relative to the operating rod 32. At this time, the locked portion 832 is separated from the locking portion 824 by a distance of angle θ in the rotational direction.

[0119] When the operating rod 32 is rotated in the opposite direction by an angle θ from this state, the locked portion 832 is locked to the locking portion 824, and the rotation of the operating rod 32 is restricted (Figure 18(D)). At this time, the clearance CL between the locking surface of the connecting member 142 and the upper surface of the locking member 146 becomes the set clearance CLset. In other words, by adjusting the relative position (angle θ) of the operating rod 32 and the locked portion 832 in the rotational direction, the set clearance CLset corresponding to that angle θ can be set. After that, the rotor 60 is press-fitted onto the operating rod 32 (Figure 18(E)).

[0120] In this modified example, with the position of the first locking member 812 fixed relative to the guide member 6, the relative positions of the operating rod 32 and the second locking member 814 in the axial and rotational directions are adjusted, thereby allowing the clearance CL to be adjusted. By accurately adjusting this clearance CL, the distance between the operating origin and the seating point can be precisely set, thereby improving the accuracy of flow rate control.

[0121] Figure 19 shows a method for adjusting the clearance CL in relation to other modified examples. Figures 19(A) to (E) show the adjustment process. The lower part of each figure is a cross-sectional view showing the area around the stopper mechanism, and the upper part is a plan view showing the state of the stopper mechanism. In this modified example, a locking portion 924 for locking the locked portion 832 is provided protruding from the guide member 906. The locking portion 924 is integrally molded with the upper peripheral edge of the guide member 906 and has a locking surface 924a that locks the locked portion 832 in the rotational direction (Figure 19(A)).

[0122] When adjusting the clearance CL, first, the operating rod 32 is rotated in one direction to raise it until it reaches the seating point (valve opening point) where the locking surface of the connecting member 142 and the upper surface of the locking member 146 come into contact (Figures 19(A), (B)). In this state, the second locking member 814 is attached to the operating rod 32 (Figure 19(C)). This attachment method is the same as the modified example shown in Figure 18(C). By adjusting the relative position (angle θ) in the rotational direction between the operating rod 32 and the locked portion 832, the set clearance CLset corresponding to that angle θ can be set (Figure 19(D)). After that, the rotor 60 is press-fitted onto the operating rod 32 (Figure 19(E)).

[0123] In this modified example as well, with the position of the locking portion 924 on the guide member 6 fixed, the relative positions of the operating rod 32 and the second locking member 814 in the axial and rotational directions are adjusted, thereby allowing the clearance CL to be adjusted.

[0124] Although preferred embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to these specific embodiments, and various modifications are possible within the scope of the technical concept of the present invention.

[0125] In the above embodiment, the friction torque of the rotor 60 is reduced by bringing the upper end surface of the operating rod 32 and the bottom surface of the can 66 into contact on the central axis L when the electric valve is fully open. This solves the problem of preventing or suppressing operation lock when the valve is opened in an electric valve having a linear stopper mechanism.

[0126] This kind of technological philosophy can be expressed, for example, as follows: A body having a fluid passage and a valve hole, A valve body that moves toward and away from the valve hole to open and close the fluid passage, An operating rod, which is provided coaxially with the valve body and is rotationally driven by a rotor, A screw feed mechanism that converts the rotational motion of the rotor into axial motion of the operating rod, A cylindrical member enclosing the rotor, comprising a can that defines an internal space where fluid pressure acts and an external space where it does not, Equipped with, An electric valve characterized in that, when the valve is opened, the rear end surface of the operating rod contacts the can on the central axis of the operating rod, thereby restricting the rotation of the rotor.

[0127] This electric valve may be a valve in which the valve body is attached to and detached from the valve seat to open and close the valve section, or it may be a spool valve in which the valve body is inserted into and removed from the valve bore to open and close the valve section. The valve body may move toward and toward the valve bore to open and close the valve section and also adjust the degree of opening of the valve section. Here, "moving toward and separating" means approaching or separating from, and includes both cases of attaching to and detaching from the valve seat and insertion into and removal from the valve bore. In the case of a spool valve, a predetermined clearance that allows fluid leakage is formed even when the valve is closed.

[0128] The contact surface of the operating rod in the can may be made of a thicker portion than the cylindrical portion. Alternatively, a reinforcing member such as a plate may be provided on the central axis of the operating rod in the can, and the contact surface may be formed on the reinforcing member. The reinforcing member functions as part of the can.

[0129] The rear end surface of the operating rod may have a curved or tapered surface that moves further away from the bottom surface of the can as it moves away from the central axis.

[0130] The rear end surface of the operating rod has a flat surface that includes the central axis and is perpendicular to the central axis, The flat surface may be continuous with the curved or tapered surface at its outer edge.

[0131] In the above embodiment, torque reduction control is performed from a predetermined timing when the valve is closed until the valve body stops at the operating origin. This prevents or suppresses problems that may arise when the operating member and rotor are fixed, such as the valve body biting into the valve seat when the valve is closed, wear of the valve seat, and screw jamming in the screw feeding mechanism. In other words, the problem of preventing or suppressing the occurrence of such problems can be solved.

[0132] This kind of technological philosophy can be expressed, for example, as follows: A body having a fluid passage and equipped with a valve seat, A valve body that is attached to and detached from the valve seat to open and close the fluid passage, A motor (stepping motor) including a rotor for driving the valve body, An operating rod, which is provided coaxially with the valve body and is rotationally driven by the rotor, A screw feed mechanism that converts the rotational motion of the rotor into axial motion of the operating rod, A control unit that controls the drive of the motor, Equipped with, The control unit is characterized by reducing the drive torque of the motor at a predetermined timing when the valve body is closed.

[0133] This torque reduction control may be performed at a timing near the seating point where the valve body seats on the valve seat (a predetermined step before the seating point). Torque reduction control may be achieved by reducing the current supplied to the motor and increasing the drive frequency. Alternatively, torque reduction control may be achieved by reducing the current supplied to the motor and, conversely, by lowering the drive frequency. That is, by lowering the motor's drive frequency, the rotor's rotational speed can be made lower than the normal control range, thereby reducing the motor's drive torque compared to the normal control state when the valve is open.

[0134] Alternatively, torque reduction control may be achieved by switching the excitation method of the stepping motor. For example, during normal control such as valve opening, half-step drive (1-2 phase excitation) may be used, and during torque reduction control, micro-step drive (W1-2 phase excitation) may be used to reduce torque. Half-step drive is a driving method that rotates the motor in increments of half the original step angle (the step angle of full-step drive such as 1-phase excitation or 2-phase excitation), while micro-step drive is a driving method that reduces the step angle even further than half-step drive.

[0135] [Other variations] In the above embodiment, a second locking member 814 provided on the operating rod 32 was exemplified as an "engaging member" that is rotationally driven by the rotor 60. In a modified example, the engaging member may be provided on the rotor 60.

[0136] In the above embodiment, as shown in Figure 1, the valve unit 100 is exemplified as a configuration in which a rotor unit 90 and a stator unit 92 are manufactured separately and each is fixed to the passage body 200. In a modified example, the rotor unit 90 and the stator unit 92 may be assembled with a connecting member to constitute an electric valve.

[0137] In the above embodiment, a structure in which the rotor and the operating rod are directly assembled is illustrated. In a modified example, a reduction mechanism may be provided between the rotor and the operating rod to adjust the degree to which the rotational motion of the rotor is converted into the translational motion of the operating rod. In other words, the amount of axial displacement of the valve body with respect to the number of rotations of the rotor may be adjusted. The reduction mechanism may be a planetary gear mechanism.

[0138] In the above embodiment, the rotational motion of the rotor is converted into translational motion (axial motion) of the actuating rod by the operation of the screw feed mechanism. At this time, the rotor also moves in translation together with the actuating rod. In a modified example, the rotor may be configured to maintain its axial position while the actuating rod moves in translation (see, for example, U.S. Patent Application Publication No. 2018 / 0135903). Alternatively, a structure may be adopted in which the rotation of the rotor is transmitted to the actuating rod via gears (see, for example, Japanese Patent Application Publication No. 2024-008534).

[0139] In the above embodiment, the stator includes a yoke having pole teeth. In a modified example, a stator including a laminated core may also be used.

[0140] In the above embodiment, the stator unit 92 is a two-phase stepping motor, but it may also be configured as a three-phase stepping motor.

[0141] In the above embodiment, the electric valve was configured as an expansion valve, but it may also be configured as an on-off valve that does not have an expansion function.

[0142] The electric valve of the above embodiment is suitably applied to refrigeration cycles using HFO-1234yf or the like as a refrigerant, but it can also be applied to refrigeration cycles using refrigerants with high operating pressure, such as carbon dioxide. In that case, an external heat exchanger such as a gas cooler is placed in place of the condenser in the refrigeration cycle.

[0143] In the above embodiment, an example was shown in which the electric valve is applied to the refrigeration cycle of an automotive air conditioning system. However, it is applicable to air conditioning systems equipped with an electric expansion valve, not limited to vehicles. It may also be configured as an electric valve to control the flow of fluids other than refrigerants, such as hot water in a hot water supply system or hydraulic fluid (hydraulic oil) in a hydraulic control device.

[0144] It should be noted that the present invention is not limited to the embodiments and modifications described above, and the components can be modified and implemented without departing from the spirit of the invention. Various inventions may be formed by appropriately combining the multiple components disclosed in the embodiments and modifications described above. In addition, some components may be deleted from all the components shown in the embodiments and modifications described above. [Explanation of symbols]

[0145] 1 Electric valve, 5 Valve body, 6 Guide member, 7 Valve housing, 8 Valve seat member, 10 Male thread, 22 Valve bore, 24 Valve seat, 26 Inlet port, 28 Outlet port, 30 Valve chamber, 32 Actuating rod, 34 Valve element, 38 Male thread, 40 Female thread, 60 Rotor, 64 Stator, 66 Can, 90 Rotor unit, 92 Stator unit, 100 Valve unit, 102 End member, 104 Rotor magnet, 109 Screw feed mechanism, 134 Press-fit section, 140 Flange section, 142 Connecting member, 144 Guide section, 146 Locking member, 148 Spring, 152 Through hole, 154 Guide section, 160 Locking surface, 200 Passage body, 210 Fluid passage, 216 Mounting hole, 310 Actuating rod, 320 Actuating rod, 322 locking part, 324 protrusion, 326 connecting member, 330 acting rod, 334 tip surface, 340 acting rod, 342 tip surface, 344 valve body, 360 valve body, 362 connecting member, 432 acting rod, 434 male thread, 446 connecting member, 446 locking member, 448 female thread, 532 acting rod, 534 locking member, 540 spacer, 550 spacer, 602 end member, 654 guide part, 660 rotor, 754 locking member, 810 stopper mechanism, 812 first locking member, 814 second locking member, 824 locking part, 832 locked part.

Claims

1. A body having a fluid passage and equipped with a valve seat, A valve body that is attached to and detached from the valve seat to open and close the fluid passage, An operating rod, which is provided coaxially with the valve body and is rotationally driven by a rotor, A screw feed mechanism that converts the rotational motion of the rotor into axial motion of the operating rod, An annular locking member is externally fitted coaxially to the tip of the aforementioned operating rod, A connecting member is assembled to the valve body, while the operating rod is inserted coaxially through it, and the operating rod and the valve body are connected via the locking member. A stopper mechanism that restricts the displacement of the operating rod in the valve closing direction, Equipped with, The locking member has a first end face that faces the end face of the valve body in the axial direction, and a second end face that is opposite to the first end face. The connecting member has a locking surface that faces the second end surface in the axial direction, When the valve is opened, the second end face comes into contact with the locking surface, thereby connecting the operating rod and the valve body in operation. When the valve is closed, the operating rod is displaced toward the valve body and the second end face separates from the locking surface, thereby releasing the operating connection. When the stopper mechanism is functioning, a predetermined clearance is formed between the locking surface and the second end surface. The clearance is set by fixing the operating rod and the locking member with a fixing means that allows adjustment of their relative positions in the axial direction. An electric valve characterized in that the stroke of the operating rod from the seating point where the valve body attaches to and detaches from the valve seat to the operating origin where the stopper mechanism functions is determined by the clearance.

2. The operating rod protrudes from the first end face toward the valve body, The stopper mechanism functions when the tip surface of the operating rod comes into contact with the end surface of the valve body due to the valve closing operation. The electric valve according to claim 1, characterized in that the clearance is set by adjusting the amount of protrusion of the operating rod from the first end face.

3. The electric valve according to claim 1, characterized in that the stopper mechanism is a rotation stopper that restricts the displacement of the operating rod in the valve closing direction by locking an engaging member, which is rotationally driven by the rotor, in the rotational direction at the operating origin.

4. The electric valve according to claim 2, characterized in that at least one of the tip surface of the operating rod and the end surface of the valve body has a convex shape that protrudes toward the other, and the convex portion abuts against the other.

5. The electric valve according to claim 2, characterized in that the tip surface of the operating rod has a curved or tapered surface that moves further away from the end surface of the valve body as it moves away from the central axis.

6. The tip surface of the operating rod has a flat surface that includes the central axis and is perpendicular to the central axis, The electric valve according to claim 5, characterized in that the flat surface is continuous with the curved surface or tapered surface at its outer peripheral edge.

7. A body having a fluid passage and equipped with a valve seat, A valve body that is attached to and detached from the valve seat to open and close the fluid passage, An operating rod, which is provided coaxially with the valve body and is rotationally driven by a rotor, A screw feed mechanism that converts the rotational motion of the rotor into axial motion of the operating rod, A connecting member is assembled to the valve body, while the operating rod is inserted coaxially through it, thereby connecting the operating rod and the valve body in operation. A stopper mechanism that restricts the displacement of the operating rod in the valve closing direction, Equipped with, A locking portion is provided at the tip of the aforementioned operating rod, which protrudes radially outward. The connecting member has a locking surface that faces the end face of the valve body in the axial direction, while forming a housing space between itself and the valve body to accommodate the locking portion. A spacer is placed in the aforementioned accommodation space, When the valve is opened, the locking portion and the locking surface are connected, thereby connecting the operating rod and the valve body in operation. When the valve is closed, the connection between the locking portion and the locking surface is released, thereby releasing the operating connection between the operating rod and the valve body. When the stopper mechanism is functioning, a clearance, which is an axial space, is formed between the locking portion and the locking surface. The clearance is set by setting the thickness of the spacer. An electric valve characterized in that the stroke of the operating rod from the seating point where the valve body attaches to and detaches from the valve seat to the operating origin where the stopper mechanism functions is determined by the clearance.

8. A body having a fluid passage and equipped with a valve seat, A valve body that is attached to and detached from the valve seat to open and close the fluid passage, An operating rod, which is provided coaxially with the valve body and is rotationally driven by a rotor, A screw feed mechanism that converts the rotational motion of the rotor into axial motion of the operating rod, A connecting member is assembled to the valve body, while the operating rod is inserted coaxially through it, thereby connecting the operating rod and the valve body in operation. A guide member fixed to the body and through which the operating rod is inserted coaxially, An engaging portion that is displaced integrally with the operating rod outside the guide member, Equipped with, A locking portion is provided at the tip of the aforementioned operating rod, which protrudes radially outward. The locking portion has a first end face that faces the end face of the valve body in the axial direction, and a second end face that is opposite to the first end face. The connecting member has a locking surface that faces the second end surface in the axial direction, When the valve is opened, the second end face comes into contact with the locking surface, thereby connecting the operating rod and the valve body in operation. When the valve is closed, the operating rod is displaced toward the valve body and the second end face separates from the locking surface, thereby releasing the operating connection. When the operating rod is displaced in the valve closing direction, the engaging portion is locked to the guide member, thereby activating a stopper mechanism that restricts the displacement of the operating rod in the valve closing direction. When the stopper mechanism is functioning, a predetermined clearance is formed between the locking surface and the second end surface. With the position in which the engaging portion is locked in the guide member fixed, the clearance is set by fixing the operating rod and the engaging portion with a fixing means that can adjust the relative position of at least one of the axial and rotational directions. An electric valve characterized in that the stroke of the operating rod from the seating point where the valve body attaches to and detaches from the valve seat to the operating origin where the stopper mechanism functions is determined by the clearance.

9. A body having a fluid passage and equipped with a valve seat, A valve body that is attached to and detached from the valve seat to open and close the fluid passage, An operating rod, which is provided coaxially with the valve body and is rotationally driven by a rotor, A screw feed mechanism that converts the rotational motion of the rotor into axial motion of the operating rod, A connecting member is assembled to the valve body, while the operating rod is inserted coaxially through it, thereby connecting the operating rod and the valve body in operation. A guide member fixed to the body and through which the operating rod is inserted coaxially, An engaging member assembled to the guide member, An engaging portion that is displaced integrally with the operating rod outside the guide member, Equipped with, A locking portion is provided at the tip of the aforementioned operating rod, which protrudes radially outward. The locking portion has a first end face that faces the end face of the valve body in the axial direction, and a second end face that is opposite to the first end face. The connecting member has a locking surface that faces the second end surface in the axial direction, When the valve is opened, the second end face comes into contact with the locking surface, thereby connecting the operating rod and the valve body in operation. When the valve is closed, the operating rod is displaced toward the valve body and the second end face separates from the locking surface, thereby releasing the operating connection. When the operating rod is displaced in the valve closing direction, the engaging portion is locked to the engaging member, thereby activating a stopper mechanism that restricts the displacement of the operating rod in the valve closing direction. When the stopper mechanism is functioning, a predetermined clearance is formed between the locking surface and the second end surface. With the position of the engaging portion relative to the operating rod fixed, the clearance is set by fixing the guide member and the engaging member with a fixing means that allows adjustment of the relative position of at least one of the axial and rotational directions. An electric valve characterized in that the stroke of the operating rod from the seating point where the valve body attaches to and detaches from the valve seat to the operating origin where the stopper mechanism functions is determined by the clearance.

10. A cylindrical member enclosing the rotor, further comprising a can that defines an internal space on which fluid pressure acts and an external space on which it does not act, The electric valve according to any one of 1, 7 to 9, characterized in that when the valve is opened, the rear end surface of the operating rod comes into contact with the can on the central axis, thereby restricting the rotation of the rotor.

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