Electric valve

Abstract

To allow a seal performance to be secured in a motor-operated valve.SOLUTION: A motor-operated valve 1 is constituted by assembling a passage body 200 and a valve unit 100. The passage body 200 comprises a female screw part 218 in an inner peripheral surface of an attachment hole 216. A valve body 5 comprises a small diameter part 9 inserted into the attachment hole 216, and a large diameter part 7 inserted into a case 76 while being exposed to the outside of the attachment hole 216. A male screw part 10 screwed to the female screw part 218 is provided in an outer peripheral surface of the small diameter part 9. The motor-operated valve 1 comprises a first seal structure for regulating leakage of fluid to the outside from the inside of the passage body 200 by a seal ring 220 interposed between opposed surfaces of the large diameter part 7 and the passage body 200 in an axial direction, and a second seal structure for regulating entry of outside air to the inside of a stator unit 92 from the outside by a seal ring 82 interposed between an outer peripheral surface of the large diameter part 7 and an inner peripheral surface of the case 76.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an electric valve, and particularly to a sealing structure of an electric valve.

Background Art

[0002] An automotive air conditioner generally comprises a compressor, a condenser, an expansion device, an evaporator, etc. arranged in a refrigeration cycle. Various control valves are provided in the refrigeration cycle to control the flow of refrigerant, such as an expansion valve as the expansion device. With the recent popularization of electric vehicles and the like, electric valves equipped with a motor as a drive unit are being widely adopted.

[0003] When installing an electric valve in a heat exchanger such as an evaporator, a valve unit is assembled to a piping body fixed to the heat exchanger (see Patent Document 1). The valve unit is configured by coaxially assembling a rotor unit enclosing a valve portion and a stator unit enclosing a stator. A refrigerant passage is provided in the piping body, and a mounting hole is provided so as to communicate with the passage.

[0004] The valve unit is assembled to the piping body in such a manner that a valve body constituting the rotor unit is inserted into the mounting hole. A male screw portion is provided on the outer peripheral surface of the valve body, and a female screw portion is provided on the inner peripheral surface of the mounting hole. By screwing these screw portions together, the valve body is fastened to the piping body.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Even in such electric valves, sealing performance is important. In the embodiment of Patent Document 1, multiple sealing rings are fitted to the outer circumferential surface of the valve body. A first sealing structure is realized by interposing a first sealing ring between the outer circumferential surface of the valve body and the inner circumferential surface of the mounting hole, thereby restricting the leakage of refrigerant from the inside to the outside of the piping body. Furthermore, a second sealing structure is realized by interposing a second sealing ring between the outer circumferential surface of the valve body and the inner circumferential surface of the stator unit, thereby restricting the intrusion of outside air from the outside into the inside of the stator unit.

[0007] However, in the embodiment of Patent Document 1, the threaded portion and the first seal structure are adjacent in the axial direction, and the dimensional difference between the inner diameter of the mounting hole to which the first seal structure is applied (i.e., the inner diameter of the sealing surface) and the outer diameter of the male threaded portion is small. Therefore, when inserting the valve body into the mounting hole, there was a risk that the male threaded portion would come into contact with the mounting hole, damaging the sealing surface and degrading the performance of the first seal structure.

[0008] One of the objectives of the present invention is to ensure sealing performance in electric valves. [Means for solving the problem]

[0009] One aspect of the present invention is an electric valve configured by assembling a passage body having a fluid passage formed therein and a valve unit, wherein the valve unit includes a rotor unit and a stator unit. The passage body has a mounting hole communicating with the fluid passage. The rotor unit includes a valve body that is inserted into the mounting hole and assembled to the passage body, a valve element that adjusts the opening degree of a valve section provided on the valve body, a rotor for driving the valve element in the opening and closing direction of the valve section, and a cylindrical member fixed coaxially to the valve body and enclosing the rotor, the can defining an internal space on which fluid pressure acts and an external space on which it does not act. The stator unit includes a stator that is externally fitted coaxially to the can and a case enclosing the stator.

[0010] The passage body has a female thread on the inner circumferential surface of the mounting hole. The valve body has a small diameter portion that is inserted into the mounting hole and a large diameter portion that is inserted into the case while being exposed to the outside of the mounting hole, and a male thread portion that screws into the female thread is provided on the outer circumferential surface of the small diameter portion. The insertion amount of the valve body into the mounting hole is restricted when the large diameter portion comes into contact with the passage body in the axial direction by screwing the small diameter portion into the mounting hole. This electric valve includes a first seal structure that restricts the leakage of fluid from the inside to the outside of the passage body by a first seal ring interposed between the axially opposing surfaces of the large diameter portion and the passage body, and a second seal structure that restricts the intrusion of outside air from the outside into the inside of the stator unit by a second seal ring interposed between the outer circumferential surface of the large diameter portion and the inner circumferential surface of the case.

[0011] According to this embodiment, the sealing performance of the electric valve is ensured by the first seal structure and the second seal structure. Since the first seal ring is positioned outside the mounting hole, the opposing surface (sealing surface) of the first seal ring is not damaged by the male thread portion, and the performance of the first seal structure can be maintained well. [Effects of the Invention]

[0012] According to the present invention, sealing performance in an electric valve can be ensured. [Brief explanation of the drawing]

[0013] [Figure 1] This is a cross-sectional view showing the structure of an electric valve according to an embodiment. [Figure 2] This is a cross-sectional view showing the structure of the valve unit. [Figure 3] This is a diagram showing the structure of the housing components in detail. [Figure 4] This is a diagram illustrating the assembly method of an electric valve. [Figure 5] This is a diagram illustrating the assembly method of an electric valve. [Figure 6] This diagram shows the detailed process of assembling the rotor unit into the passage body. [Figure 7] This is an enlarged view of section B in Figure 2. [Modes for carrying out the invention]

[0014] 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.

[0015] Figure 1 is a cross-sectional view showing the structure of an electric valve according to an 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 that compresses the circulating refrigerant, a condenser that condenses the compressed refrigerant, an expansion valve that throttles and expands the condensed refrigerant and sends it out in a mist, and an evaporator that evaporates the mist of refrigerant and cools the air in the vehicle cabin with its latent heat of vaporization. The electric valve 1 functions as the expansion valve.

[0016] 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 will be described in detail later, 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 103 fixed to the stator unit 92 and a screw 105 for fixing the metal plate 103 to the passage body 200.

[0017] 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, an outlet port 204, an inlet port 206, and an outlet port 208 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. Piping leading to the evaporator outlet is connected to the inlet port 206, and piping extending to the compressor side is connected to the outlet port 208.

[0018] The passage body 200 is formed with a first passage 210 connecting the introduction port 202 and the discharge port 204, and a second passage 212 connecting the introduction port 206 and the discharge port 208. The first passage 210 and the second passage 212 function as "fluid passages". The first passage 210 and the second passage 212 are vertically separated by a partition wall 214. An attachment hole 216 opens upward at the upper part of the passage body 200. The attachment hole 216 communicates with the first passage 210. A female screw portion 218 is formed near the opening end of the attachment hole 216.

[0019] The valve unit 100 has a valve body 5 that houses a valve portion. A male screw portion 10 that can be screwed with the female screw portion 218 is formed on the outer peripheral surface of the valve body 5. When assembling the valve unit 100 to the passage body 200, the valve body 5 with a seal ring 20 (O-ring) attached is inserted into the attachment hole 216. The male screw portion 10 and the female screw portion 218 are screwed together to fasten the valve body 5 to the passage body 200.

[0020] An annular seal accommodation portion 222 (annular groove) is provided on the upper surface of the passage body 200 so as to surround the attachment hole 216, and a seal ring 220 (O-ring) is fitted therein. 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 functions as a "first seal ring" and constitutes a "first seal structure" that regulates leakage of refrigerant from the inside to the outside of the passage body 200. The seal ring 20 seals between the upstream passage and the downstream passage of the valve portion.

[0021] FIG. 2 is a cross-sectional view showing the structure of the valve unit 100. The valve unit 100 is configured 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, but are indirectly fixed by being fixed to the passage body 200 respectively (details will be described later).

[0022] The rotor unit 90 has a valve body 5. The valve body 5 is constructed by coaxially assembling a housing member 6 and a valve seat member 8. Both the housing member 6 and the valve seat member 8 are made of stainless steel (hereinafter referred to as "SUS"). Since a valve seat 24 is provided on the valve seat member 8, a material with excellent wear resistance has been selected. The housing member 6 has better weldability than the valve seat member 8, and the valve seat member 8 has better machinability than the housing member 6.

[0023] The housing member 6 integrally has a large-diameter portion 7 and a small-diameter portion 9, forming a stepped cylindrical shape with an outer diameter that decreases downwards. The small-diameter portion 9 is shorter in the axial direction than the large-diameter portion 7. The outer diameter of the upper end of the large-diameter portion 7 is slightly reduced, forming a locking portion 52 due to the step. A seal housing portion 80, which is an annular groove, is formed on the outer circumferential surface of the large-diameter portion 7, and a seal ring 82 (O-ring) is fitted into it. A male threaded portion 10 is formed on the outer circumferential surface of the small-diameter portion 9. As shown in Figure 1, the insertion amount of the valve body 5 into the mounting hole 216 is restricted when the large-diameter portion 7 comes into contact with the passage body 200 in the axial direction by screwing the small-diameter portion 9 into the mounting hole 216.

[0024] A circular hole-shaped concave fitting portion 16 is provided at the lower part of the housing member 6 (inside the small diameter portion 9). The valve seat member 8 is a bottomed cylindrical shape, and its upper part is inserted through the concave fitting portion 16. That is, the valve seat member 8 has an insertion portion 11 that is inserted into the small diameter portion 9 and an exposed portion 13 that is exposed from the small diameter portion 9. The outer diameter of the exposed portion 13 is smaller than the outer diameter of the male thread portion 10.

[0025] In this embodiment, the outer diameter of the insertion portion 11 and the outer diameter of the exposed portion 13 are equal, and an annular recess 15 is provided on the outer circumferential surface of the exposed portion 13 near the boundary with the insertion portion 11. The valve seat member 8 is fixed to the housing member 6 by crimping the tip of the small diameter portion 9 radially inward toward the recess 15.

[0026] A seal housing portion 18, which is an annular groove, is formed on the lower outer circumferential surface of the valve seat member 8, and a seal ring 20 is fitted into it. A valve hole 22 is provided so as to penetrate the bottom of the valve seat member 8 in the axial direction, and a valve seat 24 is formed at the upper end opening of the valve hole 22.

[0027] 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. The inlet port 26 communicates with the introduction port 202, and the outlet port 28 communicates with the output port 204 (see Figure 1). An internal passage is formed in the valve seat member 8 that connects the inlet port 26 and the outlet port 28. A valve chamber 30 is formed inside the housing member 6 and the valve seat member 8. The inlet port 26 and the outlet port 28 communicate with each other via the valve chamber 30.

[0028] An operating rod 32 extending from the rotor 60 of the rotor unit 90 is inserted inside the valve body 5. The operating rod 32 penetrates the valve chamber 30. The operating rod 32 is obtained by machining a rod made of a non-magnetic metal, and a needle-shaped valve body 34 is integrally attached to its lower part. 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.

[0029] A guide member 36 is erected in the upper center of the housing member 6. The guide member 36 is obtained by machining a tubular material made of a non-magnetic metal into a stepped cylindrical shape, and a male screw 38 is formed on the outer circumferential surface of its axial center. A circular hole-shaped concave fitting portion 35 is provided in the upper part of the housing member 6 (inside the large diameter portion 7). The lower end of the guide member 36 is large in diameter, and this large diameter portion 40 is inserted into the upper center of the concave fitting portion 35 and fixed coaxially by crimping. The guide member 36 supports the operating rod 32 so that it can slide in the axial direction with its inner circumferential surface, while supporting the rotation shaft 62 of the rotor 60 so that it can rotate and slide with its outer circumferential surface. The rotation shaft 62 is made of a non-magnetic metal.

[0030] The guide member 36 and the valve seat member 8 are each inserted coaxially into the housing member 6, and face each other axially with a radially inward-facing flange portion 33 formed on the housing member 6 in between. The thickness (axial length) of the flange portion 33 is smaller than the insertion length of the guide member 36 into the housing member 6, and also smaller than the insertion length of the valve seat member 8 into the housing member 6.

[0031] 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 bottomed cylindrical member 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.

[0032] The can 66 is made of a non-magnetic metal (e.g., SUS) and is assembled coaxially so that its lower part is externally fitted onto the upper end of the housing member 6. The insertion amount of the can 66 is restricted by the locking portion 52 at its lower end. Welding (circumferential welding) is performed along the boundary between the lower end of the can 66 and the housing member 6 (not shown) to fix the valve body 5 and the can 66 and to achieve airtightness (seal). The space enclosed by the valve body 5 and the can 66 forms the pressure space.

[0033] 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 enclosed in a case 76. The case 76 is obtained by injection molding (also called "insert molding" or "mold molding") of a corrosion-resistant resin material. The stator 64 is covered with the molded resin produced by injection molding. The case 76 is made of this molded resin. The stator unit 92 is an integrated part (a molded product in this embodiment) of the stator 64 and the case 76.

[0034] The stator unit 92 has a hollow structure, and the stator 64 is assembled to the rotor unit 90 while the can 66 is inserted coaxially through it. A seal housing portion 80 is formed on the outer circumferential surface slightly below the locking portion 52 of the housing member 6, and a seal ring 82 is fitted into it. The seal ring 82 is interposed between the outer circumferential surface of the large diameter portion 7 and the inner circumferential surface of the case 76. The seal ring 82 functions as a "second seal ring" and constitutes a "second seal structure" that restricts the intrusion of outside air into the interior of the stator unit 92 from the outside.

[0035] The can 66 is assembled to the upper end of the large-diameter section 7, that is, on the opposite side from the small-diameter section 9. The weld between the can 66 and the large-diameter section 7 is located inside the case 76, on the opposite side from the small-diameter section 9 relative to the seal ring 82. In other words, because the weld is located axially inward of the case 76 compared to the second seal structure, it is not exposed to moisture entering from the outside, and thus corrosion is prevented.

[0036] In this embodiment, the outer diameter of the large-diameter portion 7 is equal to the outer diameter of the cann 66, but it may be smaller than the outer diameter of the cann 66. The axial length of the large-diameter portion 7 on the side of the small-diameter portion 9 relative to the seal housing portion 80 is sufficiently smaller than the axial length of the cann 66. Therefore, when attaching the seal ring 82 to the rotor unit 90, the seal ring 82 is fitted onto the valve body 5 from the side of the small-diameter portion 9. A pair of recesses 84, formed by a so-called D-cut, are provided slightly below the seal housing portion 80 in the large-diameter portion 7, which will be described later.

[0037] The rotor 60 comprises a cylindrical rotor core 102 mounted on a rotating shaft 62, a rotor magnet 104 provided on the outer circumferential surface of the rotor core 102, and a sensor magnet 106 provided on the upper end surface of the rotor core 102. The sensor magnet 106 is annular in shape and is mounted coaxially to the rotor core 102. The rotor magnet 104 is magnetized (contained) with multiple poles in its circumferential direction. The sensor magnet 106 is also magnetized (contained) with multiple poles.

[0038] The rotating shaft 62 is a bottomed cylindrical shaft, and its open end is fitted onto the guide member 36. A female thread 108 is formed on the lower inner surface of the rotating shaft 62 and engages with the male thread 38 of the guide member 36. Through the screw feeding mechanism 109 formed by these threads, the rotational motion of the rotor 60 is converted into the axial motion of the operating rod 32. 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.

[0039] The upper part of the operating rod 32 is reduced in diameter, and this reduced-diameter portion 110 passes through the bottom portion 112 of the rotating shaft 62. An annular stopper 114 is fixed to the tip of the reduced-diameter portion 110. Meanwhile, a spring 116 is interposed between the base end of the reduced-diameter portion 110 and the bottom portion 112 to bias the operating rod 32 downward (i.e., in the valve closing direction). With this configuration, when the valve is opened, the operating rod 32 is displaced integrally with the rotor 60 in such a manner that the stopper 114 is locked to the bottom portion 112. On the other hand, when the valve is closed, the spring 116 is compressed by the reaction force that the valve body 34 receives from the valve seat 24. The elastic reaction force of the spring 116 at this time can press the valve body 34 against the valve seat 24, thereby improving the seating performance (valve closing performance) of the valve body 34.

[0040] 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.

[0041] A magnetic sensor 119 is provided on the surface of the circuit board 118 facing the sensor magnet 106. The magnetic sensor 119 faces the sensor magnet 106 in the axial direction via the bottom end wall of the can 66. As the rotor 60 rotates, the magnetic flux from the sensor magnet 106 changes. The magnetic sensor 119 detects the displacement of the rotor 60 (in this embodiment, the rotation angle of the rotor 60) by sensing this change in magnetic flux. The control unit calculates the axial position of the valve body 34 and, consequently, the valve opening degree, based on the displacement of the rotor 60.

[0042] A terminal 120 extends from the bobbin 70 and connects to the coil 68, and is connected to the circuit board 118. Power terminals, ground terminals, and communication terminals (collectively referred to as "connection terminals 122") extend from the circuit board 118 and are brought out to the outside by penetrating the side wall of the case 76. A connector section 124 is integrally provided on the side of the case 76, and the connection terminals 122 are arranged inside the connector section 124.

[0043] Next, the structure for achieving the sealing performance of this embodiment will be described in detail. Figure 3 is a diagram showing the structure of the housing member 6 in detail. (A) is a perspective view, (B) is a front view, (C) is a top view, and (D) is a side view. (E) is a cross-sectional view of (B) taken along arrow CC, and (F) is a cross-sectional view of (C) taken along arrow DD.

[0044] The housing member 6 has a stepped cylindrical shape and a structure symmetrical with respect to the axis L. The seal housing portion 80 is a circular annular groove. The pair of recesses 84 have parallel surfaces due to a so-called D-cut. The housing member 6 can be gripped with a predetermined tool so as to sandwich the pair of recesses 84 and rotated around the axis L. In a modified example, a lateral hole may be made in the housing member 6 and the predetermined tool may be inserted through the lateral hole. The housing member 6 may then be rotated together with the tool. Alternatively, the housing member 6 may be gripped and rotated with a tool without providing recesses such as D-cuts.

[0045] Figures 4 and 5 illustrate the assembly method of the electric valve 1. Figures (A) and (B) show the assembly process. When assembling the electric valve 1, the passage body 200, rotor unit 90, and stator unit 92 are each manufactured individually. Then, the rotor unit 90 and stator unit 92 are fixed to the passage body 200, respectively.

[0046] As shown in Figure 4(A), first, the seal ring 220 is fitted into the seal housing portion 222 of the passage body 200. The seal rings 20 and 82 are fitted onto the rotor unit 90. Next, as shown in Figure 4(B), the rotor unit 90 is inserted into the mounting hole 216 from the tip side of the valve body 5. At this time, the male threaded portion 10 is screwed into the female threaded portion 218, and the rotor unit 90 is assembled to the passage body 200 while rotating it.

[0047] As shown in Figure 5(A), by fastening the rotor unit 90 to the passage body 200, the seal ring 220 is appropriately compressed, and the first seal structure becomes effective. The sealing function of the seal ring 20 is also effectively performed. The stator unit 92 is then assembled to the rotor unit 90 while being coaxially fitted onto the can 66. Prior to this assembly, a metal plate 103 is fixed to the case 76 of the stator unit 92 by welding or the like.

[0048] As shown in Figure 5(B), the stator unit 92 is fixed to the passage body 200 by fastening the metal plate 103 to the passage body 200 with screws 105. As a result, the rotor unit 90 and the stator unit 92 are also indirectly fixed. At this time, the seal ring 82 is appropriately compressed between the outer surface of the valve body 5 and the inner surface of the case 76, so that the second seal structure also functions effectively.

[0049] Figure 6 shows a detailed diagram of the assembly process of the rotor unit 90 into the passage body 200. Figures 6(A) to 6(C) correspond to enlarged sections E in Figures 4(B) and 5(A). As shown in Figures 6(A) and (B), during the process of inserting the valve body 5 into the mounting hole 216, the valve body 5 does not interfere with the seal ring 220 until just before it is fastened to the passage body 200. As shown in Figure 6(C), in the short period from just before the valve body 5 is fastened to the passage body 200 until the fastening is completed, the seal ring 220 is compressed axially by the valve body 5.

[0050] Therefore, during the process of assembling the rotor unit 90 to the passage body 200, the reaction force of the seal ring 220 does not substantially act on the threaded portion. In other words, the reaction force of the seal ring 220 does not increase friction between the male threaded portion 10 and the female threaded portion 218, thus suppressing wear on the threaded portion. As a result, the occurrence of contamination due to wear on the threaded portion and the subsequent deterioration of valve closing performance due to such contamination can be prevented.

[0051] Figure 7 is an enlarged view of section B in Figure 2. In this embodiment, a structure is adopted in which the circuit board 118 is simply fixed inside the case 76 of the stator unit 92.

[0052] As shown in Figure 2, a through-hole 94 extending parallel to the axis is provided at a specific position on the top of the case 76. By utilizing a coil spring 96 housed in this through-hole 94 to connect the ground line (not shown) of the circuit board 118 to the stator 64, electromagnetic interference from the electric valve 1 is reduced. This ground line is connected to the ground terminal. The coil spring 96 is made of conductive stainless steel (spring steel) and functions as both a "conductive member" and an "elastic member".

[0053] Specifically, the ground line formed on the lower surface of the circuit board 118 and the upper end surface of the yoke 72 are electrically connected via the coil spring 96. The coil spring 96 elastically contacts both the circuit board 118 and the yoke 72. As a result, the conductive member does not tilt or bend, and its electrical connection can be stably maintained.

[0054] In this configuration, the circuit board 118 is stably fixed by being sandwiched between the lid 77 and the coil spring 96. That is, as shown in Figure 7(A), the circuit board 118 is placed on the rib 79 inside the case 76, but before the lid 77 is assembled, it is slightly lifted from the rib 79 due to the biasing force of the coil spring 96. From this state, the lid 77 is assembled to the case 76 from above.

[0055] Near the peripheral edge of the lower surface of the lid 77, a rib 83 is provided that protrudes downward and engages with the upper opening of the case 76. On the lower surface of the rib 83, a small projection 85 is provided at a position opposite the coil spring 96 with the circuit board 118 in between. The projection 85 has a pointed shape. When the lid 77 is fitted into the case 76, the peripheral edge of the lid 77 is slightly raised from the upper surface of the case 76, as shown in the figure.

[0056] From this state, the lid 77 is pressed against the case 76 against the biasing force of the coil spring 96, and the two are welded together by irradiating the peripheral edges (contact areas) of the lid 77 and the case 76 from above with a laser. At this time, as shown in Figure 7(B), the tip of the projection 85 is slightly crushed, and the circuit board 118 is sandwiched between the rib 79 and the rib 83 and stably fixed. In other words, in this embodiment, the circuit board 118 can be fixed by utilizing the fixation of the lid 77 to the case 76 without requiring fixing means such as crimping or screwing.

[0057] 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 (see Figures 1 and 2). That is, 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 stopper 114 comes into contact with the rotation shaft 62 due to the biasing force of the spring 116, and the operating rod 32 and thus the valve body 34 operate together with the rotor 60.

[0058] The rotor 60 moves vertically via a screw feed mechanism 109 between it and the guide member 36. The valve body 34 translates in the opening and closing direction of the valve, and the valve opening is adjusted to a set opening. This 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. The control unit can detect the rotation angle of the sensor magnet 106 (rotation angle of the rotor 60) based on the detection signal of the magnetic sensor 119 and calculate the valve opening.

[0059] As described above, in this embodiment, the sealing performance of the electric valve 1 is ensured by the first sealing structure with the seal ring 220 and the second sealing structure with the seal ring 82. Since the seal ring 220 is positioned outside the mounting hole 216, the opposing surface (sealing surface) of the seal ring 220 is not damaged by the male thread portion 10, and the performance of the first sealing structure can be ensured. Furthermore, the welded portion between the valve body 5 and the can 66 is susceptible to corrosion by moisture, but by positioning the welded portion further inside the case 76 than the seal ring 82, the second sealing structure functions effectively, preventing corrosion.

[0060] Furthermore, by providing the first seal structure outside the mounting hole 216, it becomes unnecessary to assemble a seal ring on the small diameter portion 9, thus reducing its axial length. In other words, the valve body 5 can be made more compact in the axial direction, leading to a reduction in material costs.

[0061] 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.

[0062] In the above embodiment, a configuration was illustrated in which the rotor unit 90 and the stator unit 92 are indirectly fixed to the passage body 200 by assembling each of them to the passage body 200. In a modified example, the rotor unit may be directly fixed to the stator unit to form a valve unit, and that valve unit may be assembled to the passage body. The rotor unit and the stator unit may also be fixed together via a connecting member or the like. In that case as well, the same first seal structure and second seal structure as in the above embodiment are ensured.

[0063] In the above embodiment, the female thread portion 218 is provided near the opening end of the mounting hole 216, but it may also be provided at a position spaced away from the opening end. A step may be provided at the opening end of the mounting hole 216, and the female thread portion may be provided at the step. However, from the viewpoint of miniaturizing the valve body 5, it is preferable to provide the female thread portion 218 near the opening end of the mounting hole 216.

[0064] In the above embodiment, an example was shown in which the housing member 6 and the valve seat member 8 are assembled coaxially to form the valve body 5. In a modified example, the valve body may be formed by machining a single member.

[0065] In the above embodiment, a configuration was shown in which the outer diameters of the insertion portion 11 and the exposed portion 13 of the valve seat member 8 are equal. In a modified example, the outer diameter of the insertion portion 11 may be smaller than the outer diameter of the exposed portion 13. This may ensure the thickness of the small diameter portion 9 in the housing member 6 and the strength of the male thread portion 10. Alternatively, assuming that the strength of the male thread portion 10 is sufficient, the outer diameter of the small diameter portion 9 may be made even smaller.

[0066] In the above embodiment, a configuration in which the housing member 6 and the valve seat member 8 are crimped together is illustrated. In a modified example, the insertion portion 11 of the valve seat member 8 may be press-fitted into the concave fitting portion 16 of the housing member 6 to fix the two together.

[0067] In the above embodiment, the electric valve 1 is exemplified as having a configuration in which a valve body 34 attaches to and detaches from a valve seat 24 to open and close the valve section. In a modified example, a spool valve may be used in which the valve body is inserted into and removed from a valve hole to open and close the valve section. The valve body may move toward and toward the valve hole 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 hole. In the case of a spool valve, a predetermined clearance that allows fluid leakage even in the closed valve state may be formed.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] The electric valve of the above embodiment is suitably applied to refrigeration cycles that use alternative fluorocarbons (HFC-134a) as refrigerants, but it can also be applied to refrigeration cycles that use 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.

[0072] 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.

[0073] 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]

[0074] 1 Electric valve, 5 Valve body, 6 Housing member, 7 Large diameter section, 8 Valve seat member, 9 Small diameter section, 10 Male thread section, 11 Insertion section, 13 Exposed section, 15 Recess, 16 Recessed fitting section, 18 Seal housing section, 20 Seal ring, 22 Valve hole, 24 Valve seat, 26 Inlet port, 28 Outlet port, 30 Valve chamber, 32 Operating rod, 33 Flange section, 34 Valve body, 35 Recessed fitting section, 36 Guide member, 60 Rotor, 62 Rotating shaft, 64 Stator, 66 Can, 68 Coil, 70 Bobbin, 72 Yoke, 76 Case, 77 Cover, 79 Rib, 80 Seal housing section, 82 Seal ring, 83 Rib, 84 Recess, 85 Projection, 90 Rotor unit, 92 Stator unit, 94 Insertion hole, 96 Coil spring, 100 valve unit, 101 connecting member, 106 sensor magnet, 109 screw feed mechanism, 118 circuit board, 119 magnetic sensor, 200 passage body, 202 inlet port, 204 outlet port, 206 inlet port, 208 outlet port, 210 first passage, 212 second passage, 216 mounting hole, 218 female thread section, 220 seal ring, 222 seal housing section.

Claims

1. An electrically operated valve configured by assembling a passage body having a fluid passage formed therein and a valve unit, the valve unit including a rotor unit and a stator unit, the passage body has a mounting hole communicating with the fluid passage; The rotor unit includes: a valve body that is inserted into the mounting hole and assembled to the passage body; a valve element for adjusting the opening degree of a valve portion provided in the valve body; a rotor for driving the valve body in the opening and closing direction of the valve portion; a can, which is a cylindrical member fixed coaxially to the valve body and containing the rotor, and which defines an internal space on which fluid pressure acts and an external space on which fluid pressure does not act; Including, The stator unit includes: a stator coaxially inserted around the can; a case containing the stator; Including, The passage body has a female thread portion on an inner peripheral surface of the mounting hole, the valve body has a small diameter portion that is inserted into the mounting hole and a large diameter portion that is exposed to the outside of the mounting hole and is inserted into the case, and an external thread portion that is threadedly engaged with the internal thread portion is provided on an outer peripheral surface of the small diameter portion, When the small diameter portion is threaded into the mounting hole, the large diameter portion comes into axial contact with the passage body, thereby restricting the insertion amount of the valve body into the mounting hole, a first seal structure that restricts leakage of fluid from the inside to the outside of the passage body by a first seal ring interposed between opposing surfaces of the large diameter portion and the passage body in the axial direction; a second seal structure that restricts intrusion of outside air into the stator unit from the outside by a second seal ring interposed between an outer peripheral surface of the large diameter portion and an inner peripheral surface of the case; An electrically operated valve comprising:

2. the second seal ring is fitted into a seal receiving portion provided on an outer peripheral surface of the large diameter portion, the can is assembled to the large diameter portion on the opposite side of the small diameter portion, the outer diameter of the large diameter portion is equal to or smaller than the outer diameter of the can, 2. The motor-operated valve according to claim 1, wherein the axial length of the large diameter portion on the side of the small diameter portion from the seal receiving portion is shorter than the axial length of the can.

3. the can is fixed airtightly to the large diameter portion by welding, 3. The motor-operated valve according to claim 1, wherein the welded portion between the can and the large diameter portion is located inside the case on the opposite side of the small diameter portion with respect to the second seal ring.

4. The rotor unit and the stator unit are each fixed to the passage body; 4. The motor-operated valve according to claim 1, wherein the rotor unit is not directly fixed to the stator unit.

5. The valve body includes a housing member and a valve seat member arranged coaxially, the housing member is formed in a stepped cylindrical shape having the large diameter portion and the small diameter portion integrally formed therewith, 5. The motor-operated valve according to claim 1, wherein the valve seat member has an inlet port that opens to an upstream side of the fluid passage, an outlet port that opens to a downstream side of the fluid passage, and a valve hole provided in an internal passage that connects the inlet port and the outlet port.

6. the valve seat member has an insertion portion that is inserted into the small diameter portion and an exposed portion that is exposed from the small diameter portion, 6. The motor-operated valve according to claim 5, wherein the outer diameter of the insertion portion is equal to or smaller than the outer diameter of the exposed portion, and the outer diameter of the exposed portion is smaller than the outer diameter of the male thread portion.

7. a recess is provided on an outer peripheral surface of the exposed portion near a boundary with the insertion portion, 7. The motor-operated valve according to claim 6, wherein the valve seat member is fixed to the housing member by crimping a tip end of the small diameter portion toward the recess.

8. The rotor unit includes: an actuation rod having the valve body at its tip end and driven by the rotor; a guide member that is coaxially assembled to the housing member and supports the actuation rod so that the actuation rod can slide in the axial direction; further comprising the guide member and the valve seat member are coaxially inserted through the housing member, and are opposed to each other in the axial direction with a flange portion formed on the housing member and extending radially inward therebetween, The electric valve according to any one of claims 5 to 7, characterized in that the flange portion is axially smaller than both the insertion length of the guide member into the housing member and the insertion length of the valve seat member into the housing member.

Images