Manufacturing method of electric valves

Abstract

To provide an electric valve capable of setting a valve opening of a valve port to a predetermined valve opening by a comparatively simple assembling step, and improving the controllability of a minute flow rate area by reducing the variation of a flow rate at zero pulse.SOLUTION: A method of manufacturing an electric valve includes a valve closing reference point setting step, a rotation reference point setting step, and an adhering step. In the adhering step, concerning a rotor shaft 54 set at a valve closing reference point and a magnet rotor 55 set at a rotation reference point, while the magnet rotor 55 is pressed by a pressing jig 60, the rotor shaft 54 is relatively rotated in a valve opening direction on one side around an axis L with respect to the magnet rotor 55 and the like; a relative rotation angle of the rotor shaft 54 and the magnet rotor 55 is set to be a predetermined setting amount; and while holding the predetermined setting amount, the magnet rotor 55 and the rotor shaft 54 are adhered with each other.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an electric valve.

Background Art

[0002] Conventionally, an electric valve used in a refrigeration circuit such as an air conditioner or a refrigerator has a magnet rotor disposed in a case of a motor unit, a valve body held at the lower part of a rotor shaft of the magnet rotor, and a driving male screw of the rotor shaft screwed into a driving female screw of a support member in the case, and is configured to rotate the magnet rotor and open and close a valve port with a valve body by a screw feed action. In recent years, improvement of energy saving has been actively studied for air conditioners and refrigerators, and similar performance is also required for the electric valves used in their refrigeration circuits. Performance required for an electric valve includes, for example, improvement of controllability in a minute flow rate range and reduction of flow rate variation.

[0003] In particular, for an electric valve for a room air conditioner (RAC), unlike an electric valve for a commercial air conditioner (PAC, building multi, etc.), there are specifications in which the valve body of the electric valve does not require shut-off performance, and a valve opening specification is adopted in which the valve body (needle) does not seat on the valve seat (valve port) at the zero pulse (0pls) which is the rotation reference point of the magnet rotor. In this case, it is required to reduce the flow rate tolerance of the minute flow rate at zero pulse rather than the controllability in the minute flow rate range. That is, the flow rate at zero pulse may vary greatly depending on the assembly accuracy of the electric valve and the accuracy of the used parts, and it is required to reduce this variation.

[0004] For example, Patent Document 1 discloses an assembly method for an electric valve that includes a mechanism for determining a control origin position, which is the lowest position of the valve stem during use, and an assembly stopper mechanism (movable stopper and fixed stopper) for detecting an assembly reference position where the valve stem is lowered further than the control origin position, thereby improving the control accuracy of flow rate, etc. In this assembly method, the valve stem is rotated in one direction by an assembly motor, the rate of change of the load torque required for that rotation is calculated, and the position where the rate of change exceeds a threshold is set as the assembly reference position. Furthermore, with the valve body positioned at the assembly reference position, one amount of descent of the valve stem is set as the design value of descent from the seating position of the valve body until the movable stopper contacts the fixed stopper, and another amount of descent of the valve stem is set as the design value of descent from the seating position of the valve body to the control origin position. The valve stem is then rotated in the reverse direction by the amount obtained by subtracting the other amount of descent from the first amount of descent, thereby raising the valve body and setting the control origin position. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Patent No. 6762046 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, conventional methods for assembling electric valves require calculating the rate of change of the load torque required to rotate the valve shaft, or rotating the valve shaft in the opposite direction based on the difference in the downward amount of the valve shaft as a design value. This necessitates the use of an assembly motor to rotate the valve shaft, which complicates the assembly equipment and process, making it difficult to easily reduce minute flow rate variations during zero-pulse conditions.

[0007] The present invention aims to provide an electric valve that allows the valve opening of the valve port to be set to a predetermined valve opening through a relatively simple assembly process, thereby reducing flow rate fluctuations during zero pulses and improving controllability in the minute flow rate range. [Means for solving the problem]

[0008] To solve the aforementioned problems and achieve the objective, the present invention provides a method for manufacturing an electric valve, comprising: a cylindrical valve body having a main valve chamber and a main valve port; a main valve body provided to be able to open and close the main valve port and having a sub-valve port inside; a sub-valve body that approaches or separates from the sub-valve port; a rotor shaft provided to be rotatable about an axis and driving the sub-valve body to move back and forth in the axial direction; a support member that supports the rotor shaft; a magnet rotor that rotates about an axis together with the rotor shaft; a case mounted on the valve body and housing the magnet rotor; and a stator coil mounted on the valve body and surrounding the magnet rotor, wherein the electric valve is manufactured using a pressing jig that presses the magnet rotor from one side to the other in the axial direction, wherein the case and the stator coil are not mounted on the valve body, and the sub-valve body is seated on the sub-valve port, and the sub-valve port is moved from an open state to a closed state. The invention provides a valve closing reference point setting step, which sets a valve closing reference point for the rotor shaft, which is the point at which the valve switches; a rotation reference point setting step, which sets a rotation reference point for the magnet rotor, which is the point at which the magnet rotor reaches the other end in the axial direction; and a fixing step, which fixes the rotor shaft and the magnet rotor to each other, wherein in the fixing step, with respect to the rotor shaft set as the valve closing reference point in the valve closing reference point setting step and the magnet rotor set as the rotation reference point in the rotation reference point setting step, the rotor shaft is rotated relative to the magnet rotor, the support member, the main valve body, and the valve body with respect to the magnet rotor, the support member, the main valve body, and the valve body with respect to the magnet rotor, the support member, the main valve body, and the valve body, and the relative rotation angle between the rotor shaft and the magnet rotor is set to a predetermined set amount, and the magnet rotor and the rotor shaft are fixed to each other while maintaining the predetermined set amount.

[0009] According to the present invention, the relative rotation angle between the rotor shaft and the magnet rotor can be set to a predetermined amount by a relatively simple assembly process in which the rotor shaft is positioned at the valve closing reference point, the magnet rotor is positioned at the rotation reference point, and the magnet rotor is held in place by a holding jig, while the rotor shaft is rotated relative to the magnet rotor, support member, main valve body, and valve body in the valve opening direction. Therefore, by rotating the rotor shaft, which is located at the valve closing reference point, by a predetermined amount, the valve opening degree when the sub-valve port changes from a closed state to an open state can be kept constant, and the flow rate variation of minute flow rates during zero pulses can be easily reduced. Thus, an electric valve can be provided in which the valve opening degree of the sub-valve port can be set to a predetermined valve opening degree by a relatively simple assembly process, thereby reducing the flow rate variation during zero pulses and improving the controllability of the minute flow rate range. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide an electric valve that can set the valve opening of the valve port to a predetermined valve opening through a relatively simple assembly process, thereby reducing flow rate fluctuations during zero pulses and improving controllability in the minute flow rate range. [Brief explanation of the drawing]

[0011] [Figure 1] Assembly cross-sectional view of an electric valve according to one embodiment of the present invention. [Figure 2] (A) is a cross-sectional view taken along line AA in Figure 2(B), and (B) is a diagram showing the process of bringing the slider into contact with the lower end stopper in the manufacturing process of the electric valve. [Figure 3] (A) is a cross-sectional view taken along the line BB in Figure 3(B), and (B) is a diagram showing the process of seating the auxiliary valve body on the auxiliary valve seat in the manufacturing process of an electric valve. [Figure 4] (A) is a cross-sectional view taken along the CC line in Figure 4(B), and (B) is a diagram showing the process of attaching the magnetic rotor in the manufacturing process of an electric valve. [Figure 5](A) is a cross-sectional view taken along the line DD in Figure 5(B), and (B) is a diagram showing the process of setting the retaining jig in the manufacturing process of an electric valve. [Figure 6] (A) is a cross-sectional view taken along the line EE in Figure 6(B), and (B) is a diagram showing the process of setting the receiving jig in the manufacturing process of an electric valve. [Figure 7] (A) is a cross-sectional view taken along the FF line in Figure 7(B), and (B) is a diagram showing the process of rotating the rotor shaft in the manufacturing process of an electric valve. [Figure 8] (A) is a cross-sectional view taken along the GG line in Figure 8(B), and (B) is a diagram showing the process of joining the rotor shaft and the magnet rotor in the manufacturing process of an electric valve. [Figure 9] (A) is a cross-sectional view taken along the line HH in Figure 9(B), and (B) is a diagram showing the process of attaching the case in the manufacturing process of an electric valve. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described below with reference to Figures 1 to 9. In the following description, the concept of "up and down" corresponds to up and down in the drawing of Figure 1. Also, the expressions "clockwise" and "counterclockwise" indicate the direction of rotation when the electric valve 1 is viewed from above. The electric valve 1 manufactured by the electric valve manufacturing method of the present invention comprises a valve body 10, a guide member 20 (support member), a main valve body 30, a sub-valve body 40, and a drive unit 50. The valve body 10 is formed in a substantially cylindrical shape from, for example, brass or stainless steel, and has a main valve chamber 11 inside. A first coupling pipe 12, which is connected to the main valve chamber 11, is connected to one side of the outer circumference of the valve body 10. A cylindrical portion 13 extending downward is formed at the lower end of the valve body 10, and a second coupling pipe 14 is connected to the cylindrical portion 13.

[0013] Inside the valve body 10, a cylindrical main valve seat 15 extending in the direction of axis L is formed in the portion of the second joint pipe 14 that is continuous with the upper end (the end on the main valve chamber 11 side), and the inside of the main valve seat 15 constitutes a main valve port 16. The main valve port 16 is a cylindrical hole centered on axis L. The second joint pipe 14 is electrically connected to the main valve chamber 11 via the main valve port 16. In this embodiment, the main valve seat 15 is integrally formed with the valve body 10, but a valve seat member having the main valve port 16 may be provided separately from the valve body 10, and this valve seat member may be assembled to the valve body 10. A case 17 is airtightly fixed to the upper end of the valve body 10 by welding or the like. The case 17 is formed in a bottomed cylindrical shape with the top side as the bottom, and the various components constituting the drive unit 50 are arranged inside and outside it. Multiple dimples 18, which are recessed radially inward, are formed on the outer circumferential surface of the lower end of the case 17, spaced apart in the circumferential direction. The dimples 18 are portions that engage with protrusions (not shown) provided on the stator coil 56 side when the stator coil 56, which will be described later, is fixed to the case 17, thereby connecting the stator coil 56 and the case 17.

[0014] A guide member 20 is attached to the opening at the upper end of the valve body 10 to support and guide the rotor shaft 54, which will be described later. The guide member 20 has a substantially cylindrical holder portion 21 centered on the axis L, a fitting portion 22 that protrudes radially outward from the outer circumferential surface of the holder portion 21 over its entire circumference and fits into the opening at the upper end of the valve body 10, a stopper portion 23 extending from the upper part of the holder portion 21, and a ring-shaped fixing bracket 24 made of a metal plate integrally provided on the fitting portion 22 by insert molding. The holder portion 21, fitting portion 22 and stopper portion 23 are constructed as a single piece made of resin, and the fixing bracket 24 is integrally provided with the resin fitting portion 22 by insert molding.

[0015] The fixing fitting 24 is fixed to the upper end portion of the valve body 10 by welding. In this embodiment, with the fitting portion 22 fitted into the opening at the upper end of the valve body 10, the guide member 20 is fixed to the valve body 10 by welding and fixing the fixing fitting 24 to the upper end portion of the valve body 10. However, the fixing structure of the guide member 20 is not limited to this, and the fixing fitting 24 may be fixed to the valve body 10 with the fitting portion 22 press-fitted into the valve body 10. Inside the holder portion 21, a guide hole 25 is formed which opens toward the lower side (main valve chamber 11 side) and houses the main valve body 30 inside. The guide hole 25 is formed coaxially with the axis L, and its inner peripheral surface slidably contacts the outer peripheral surface of the main valve body 30 to guide the main valve body 30 to move forward and backward in the direction of the axis L.

[0016] Inside the holder portion 21 and the stopper portion 23, an insertion hole 26 is formed which communicates with the guide hole 25 and penetrates in the direction of the axis L. The insertion hole 26 is a hole for guiding the forward and backward movement of the rotor shaft 54 described later, and on the upper inner peripheral surface, an internal thread 27 is formed which is screwed onto an external thread 58 formed on the outer peripheral surface of the rotor shaft 54. On the outer peripheral surface of the stopper portion 23, a spiral guide groove 28 is formed, and a coil-shaped slider 29 is installed in the guide groove 28. The slider 29 has a claw portion 29a protruding radially outward, and the claw portion 29a is adapted to contact a magnet rotor 55 described later. With this configuration, when the magnet rotor 55 rotates, its rotational force is transmitted to the slider 29 via the claw portion 29a, and the slider 29 rotates. Then, due to this rotation, the slider 29 moves up and down along the guide groove 28.

[0017] The main valve body 30 comprises a substantially cylindrical main valve portion 31 that can seat and separate from the main valve seat 15 and open and close the main valve port 16, and a cylindrical retaining portion 32 that forms the side wall of the main valve body 30 and has a sub-valve chamber 32a inside. A cylindrical opening 31a is formed on the inside of the main valve portion 31, opening downward (towards the main valve port 16), and a cylindrical first sound-absorbing member 33 made of a mesh-like or porous material is arranged inside the opening 31a. The displacement of the first sound-absorbing member 33 in the direction of the axis L is restricted by a retaining ring 33a located at its lower end. A cylindrical sub-valve seat 34 extending in the direction of the axis L is formed between the main valve portion 31 and the retaining portion 32, and a sub-valve port 34a is formed in the sub-valve seat 34 that penetrates in the direction of the axis L with the axis L as its center. The sub-valve port 34a connects the sub-valve chamber 32a located on the upper side with the opening 31a located on the lower side. Between the main valve section 31 and the retaining section 32, multiple radially penetrating communication passages 35 are formed around the axis L, thereby connecting the main valve chamber 11 and the sub-valve chamber 32a via the communication passages 35.

[0018] A second sound-absorbing member 36 is installed in the lower part of the interior of the sub-valve chamber 32a, through which fluid flows in or out of the sub-valve chamber 32a via a communication passage 35. The second sound-absorbing member 36, like the first sound-absorbing member 33, is made of a mesh-like or porous material and is formed in an annular shape. The second sound-absorbing member 36 is fixed by being sandwiched in the axial direction L by a first spacer 37a placed on the upper surface of the sub-valve seat 34 and a second spacer 37b positioned above the first spacer 37a. A cylindrical bearing 38 is installed on the upper part of the second spacer 37b. The outer circumferential surface of the bearing 38 is in contact with the inner circumferential surface of the retaining part 32. The inner circumferential surface of the bearing 38 is slidable in contact with the outer circumferential surface of the guide boss part 41 of the sub-valve body 40, which will be described later, and through this sliding contact, the bearing 38 guides the sub-valve body 40 to move back and forth in the axial direction L. A retainer 39 is installed on the upper part of the bearing 38 to prevent the bearing 38 from coming off. The retainer 39 is fitted into the upper end opening of the holding portion 32. Above the retainer 39 is a main valve spring 39a that biases the main valve body 30 downward (towards the main valve port 16). The main valve spring 39a is, for example, a compression coil spring, with its lower end in contact with the upper end of the retainer 39 and its upper end in contact with the upper end of the guide hole 25 of the guide member 20 described above.

[0019] The pilot valve body 40 is integrally provided at the lower end of a rotor shaft 54, which will be described later. The pilot valve body 40 is composed of a guide boss portion 41 formed with a larger diameter than the rotor shaft 54, and a needle valve 42 protruding downward from the center of the guide boss portion 41. The guide boss portion 41 is inserted into a bearing 38 of the main valve body 30, and its outer peripheral surface is in sliding contact with the inner peripheral surface of the bearing 38 and is guided in the direction of the axis L. The upper end portion of the guide boss portion 41 is adapted to engage with the upper end portion of the bearing 38. In this state, when the guide boss portion 41 moves upward, the pilot valve body 40 and the main valve body 30 rise integrally. Thereby, the main valve port 16 is opened and a large flow rate control of the fluid is performed. The needle valve 42 is a valve that approaches or separates from the pilot valve port 34a, and its tip is provided so as to be insertable into the pilot valve port 34a in the direction of the axis L. In a state where the needle valve 42 is inserted into the pilot valve port 34a, a fluid with a small flow rate flows through the gap between the needle valve 42 and the pilot valve port 34a, and thereby a small flow rate control is performed. In the present embodiment, the pilot valve body 40 and the rotor shaft 54 are integrally provided, but the pilot valve body 40 and the rotor shaft 54 may be formed separately and assembled together.

[0020] The drive unit 50 includes a stepping motor 51, a screw feed mechanism 52 that drives the pilot valve body 40 to advance and retreat by the rotation of the stepping motor 51, and a stopper mechanism 53 that regulates the rotation of the stepping motor 51. The stepping motor 51 includes a rotor shaft 54, a magnet rotor 55 disposed inside the case 17 and rotatable around the axis L, a stator coil 56 disposed on the outer periphery of the case 17 so as to face the magnet rotor 55 in the radial direction and surrounding the magnet rotor 55, and others constituted by a yoke, an exterior member, etc. The rotor shaft 54 is a rotating shaft that drives the pilot valve body 40 to advance and retreat in the direction of the axis L, is attached to the center of the magnet rotor 55 via a bush 57, extends in the direction of the axis L, and is rotatable around the axis L integrally with the magnet rotor 55.

[0021] The upper end portion of the rotor shaft 54 ​​is provided with a small-diameter shaft portion 54a that fits into a guide hole provided in the center of the bush 57, and a receiving portion 54b that is continuous with the lower end of the small-diameter shaft portion 54a and has an outer diameter slightly larger than the inner diameter of the guide hole of the bush 57. A male screw 58 is formed on the outer circumferential surface of the lower side of the receiving portion 54b on the upper part of the rotor shaft 54. The male screw 58 is screwed into the female screw 27 of the guide member 20. When the male screw 58 rotates together with the magnet rotor 55, it is fed by the screw and moves in the axial direction L relative to the female screw 27. In other words, the female screw 27 and the male screw 58 constitute a screw feeding mechanism 52.

[0022] The magnet rotor 55 is formed by molding a base material mixed with magnetic powder, and comprises a disc-shaped disc portion 55a and a cylindrical magnet portion 55b that protrudes downward from the outer edge of the disc portion 55a. A bush 57 is integrally provided in the center of the disc portion 55a by insert molding. The rotor shaft 54 ​​described above is inserted through the bush 57 and fixed by welding or the like. As a result, the magnet rotor 55 rotates together with the rotor shaft 54 ​​around the axis L. A protruding setting stopper 55c is formed on the upper surface of the disc portion 55a. The setting stopper 55c is the part that is inserted into a setting stopper guide 64, which is a hole formed in the retaining jig 60 described later, during the manufacturing of the electric valve 1, and defines the position of the magnet rotor 55 relative to the retaining jig 60.

[0023] A magnet pin 55d is formed on the inner circumferential surface of the magnet portion 55b as a projection that protrudes radially inward and extends in the direction of the axis L. The magnet pin 55d is the part that contacts the claw portion 29a of the slider 29 when the magnet rotor 55 rotates, and transmits the rotational force of the magnet rotor 55 to the slider 29. With this configuration, when the magnet rotor 55 rotates, its rotational force is transmitted to the slider 29 via the magnet pin 55d and the claw portion 29a, causing the slider 29 to rotate. This rotation causes the slider 29 to move up and down along the guide groove 28. The stator coil 56 is connected to a control unit (not shown), and upon receiving a pulse signal from the control unit, it rotates the magnet rotor 55 clockwise or counterclockwise around the axis L by a predetermined rotation angle in accordance with the pulse signal.

[0024] The stopper mechanism 53 includes a guide groove 28 in the stopper portion 23 of the guide member 20 described above, an upper end stopper (not shown) provided at the upper end of the guide groove 28, and a lower end stopper 28a provided at the lower end of the guide groove 28. The upper end stopper is composed of a projection that protrudes radially outward, and is formed so that one surface facing in the circumferential direction (the rotation direction of the slider 29) abuts the claw portion 29a of the slider 29 in the circumferential direction. On the other hand, as shown in Figure 2(A), the lower end stopper 28a is composed of a projection that protrudes radially outward, and is formed so that one surface 28b facing in the circumferential direction abuts the other surface 29b of the claw portion 29a of the slider 29 in the circumferential direction.

[0025] In this configuration, the slider 29 stops rotating by contacting the upper stopper, thereby restricting the rotation of the magnet rotor 55. At this time, the magnet rotor 55, whose rotation is restricted by the upper stopper, is prevented from being displaced upward. Similarly, the slider 29 stops rotating by contacting the lower stopper 28a, thereby restricting the rotation of the magnet rotor 55. At this time, the magnet rotor 55, whose rotation is restricted by the lower stopper 28a, is prevented from being displaced downward. In other words, the upper stopper and the lower stopper 28a define the uppermost and lowermost positions of the rotor shaft 54 ​​and the magnet rotor 55.

[0026] With the above configuration, when the stepping motor 51 is driven, the magnet rotor 55 and rotor shaft 54 ​​rotate by a predetermined rotation angle in response to a pulse signal sent from the control unit to the stator coil 56, and the magnet rotor 55 and rotor shaft 54 ​​move in the axial direction L by the screw feed mechanism 52 of the male screw 58 and female screw 27. Then, the sub-valve body 40 moves in the axial direction L, and the needle valve 42 of the sub-valve body 40 moves closer to or further away from the sub-valve port 34a. At this time, a small flow rate of fluid flows through the gap between the needle valve 42 and the sub-valve port 34a, thereby performing small flow rate control. When the sub-valve body 40 rises, the guide boss portion 41 of the sub-valve body 40 engages with the bearing 38 of the main valve body 30, and the main valve body 30 moves together with the sub-valve body 40, and the main valve portion 31 of the main valve body 30 separates from the main valve seat 15. As a result, the main valve port 16 opens, and large flow rate control is performed as fluid flows through the main valve port 16.

[0027] Next, the manufacturing method for the electric valve 1 will be described. The manufacturing method for the electric valve uses two types of jigs and one type of tool. First, the structures of the two types of jigs and the one type of tool will be described, and then each assembly process in the manufacturing method for the electric valve will be described. The two types of jigs consist of a pressing jig 60 and a receiving jig 70. The one type of tool consists of a gripping member 80. As shown in Figures 5(A) and (B), the pressing jig 60 is attached to cover the upper side and outer circumference of the magnet rotor 55 of the electric valve 1 when the case 17 and stator coil 56 are not attached, and is a jig that presses the electric valve 1 downward (from one side to the other in the direction of the axis L). The pressing jig 60 comprises a disc-shaped main body 61 and a cylindrical holding part 62 that protrudes downward from the lower surface of the main body 61. A through hole 63 is formed in the center of the main body 61, which penetrates in the direction of the axis L and through which the upper end of the rotor shaft 54 ​​is inserted. The through-hole 63 has an upper opening with a larger inner diameter than the lower opening, which causes the inner circumferential surface to form an inclined surface with respect to the axis L.

[0028] Radially outward from the through hole 63, a setting stopper guide 64 is formed, which is a hole that penetrates in the axial direction L. As shown in Figure 5(A), the setting stopper guide 64 is formed in a substantially trapezoidal shape when viewed in cross-section from the axial direction L, and the setting stopper 55c of the magnet rotor 55 described above is inserted through it with a gap to the outside. In the center of the holding portion 62, a first fitting recess 65 is formed that opens downwards. The inner shape of the first fitting recess 65 is formed to follow the outer shape of the magnet rotor 55, as shown in Figure 5(B). Specifically, the bottom portion 66 of the first fitting recess 65 is formed to follow the shape of the upper surface of the magnet rotor 55. The side portion 67 of the first fitting recess 65 is formed to follow the shape of the outer circumferential surface of the magnet rotor 55.

[0029] The receiving jig 70 is a jig that supports the electric valve 1, which is pressed by the pressing jig 60, from the bottom to the top. As shown in Figure 6(B), the receiving jig 70 comprises a first cylindrical portion 71, a second cylindrical portion 72 spaced apart from the first cylindrical portion 71 in the axial direction L, and an elastic portion 73 interposed between the first cylindrical portion 71 and the second cylindrical portion 72. The first cylindrical portion 71 has a second fitting recess 74 that opens upward. The second fitting recess 74 is sized to accommodate the cylindrical portion 13 of the valve body 10 described above, and when the cylindrical portion 13 is fitted, its opening edge contacts the lower surface of the valve body 10. The second cylindrical portion 72 is provided coaxially with the first cylindrical portion 71 with respect to the axial direction L and extends in the axial direction L. The elastic portion 73 is, for example, a compression coil spring, with its upper end in contact with the lower end surface of the first cylindrical portion 71 and its lower end in contact with the upper end surface of the second cylindrical portion 72.

[0030] As shown in Figure 7(B), the gripping member 80 includes a clamping portion 81 that holds the upper end of the rotor shaft 54 ​​when it is inserted through the through hole 63 of the pressing jig 60. As shown in Figure 7(A), the clamping portion 81 is formed in a substantially trapezoidal shape when viewed from the direction of the axis L, and for example, three are provided at equal intervals in the circumferential direction with respect to the axis L, and each is provided so as to press the outer circumferential surface of the rotor shaft 54 ​​radially inward. As shown in Figure 7(B), the gripping member 80 is formed so as not to interfere with the inner circumferential surface of the through hole 63. This makes it possible to rotate the rotor shaft 54 ​​held by the clamping portion 81 without it touching the pressing jig 60.

[0031] When manufacturing the electric valve 1, first, as the first step, as shown in Figure 2(B), the parts other than the case 17, magnet rotor 55, and stator coil 56 are assembled to prepare the electric valve 1 in a state where the main valve body 30 closes the main valve port 16. Then, the slider 29 is moved to the lowest position. That is, as shown in Figure 2(A), the surface 29b of the claw portion 29a of the slider 29 is brought into circumferential contact with the surface 28b of the lower end stopper 28a of the guide member 20. Next, as the second step (valve closing reference point setting step), as shown in Figure 3(B), the inside of the second joint pipe 14 is pressurized from the bottom to the top, and fluid is flowed as shown by the white arrow in Figure 3(B), and the flow rate of the fluid passing through the sub-valve port 34a is measured. At this time, the needle valve 42 is pressed from the bottom to the top, and the needle valve 42 moves upward within the play of the male screw 58 and female screw 27. In this state, the rotor shaft 54 ​​is rotated around its axis (clockwise in this embodiment) to seat the needle valve 42 on the sub-valve seat 34 and close the sub-valve port 34a. This defines the valve closing reference point of the rotor shaft 54, which is the point at which the sub-valve port 34a switches from an open state to a closed state.

[0032] In this embodiment, the valve closing reference point for the needle valve 42 was defined as the position where the needle valve 42 is seated on the sub-valve seat 34 and the flow rate of the fluid flowing through the sub-valve port 34a becomes zero. However, the valve closing reference point is not limited to this. For example, the valve closing reference point for the needle valve 42 may be defined as the position where the amount of fluid flowing through the sub-valve port 34a falls below a certain level (the position where it falls below a predetermined valve leakage amount). Also, in this embodiment, the valve closing reference point was defined by pressurizing the inside of the second joint pipe 14 from bottom to top, measuring the flow rate of the fluid passing through the sub-valve port 34a, and rotating the rotor shaft 54 ​​in this state. However, the valve closing reference point may be defined simply by rotating the rotor shaft 54 ​​and manually detecting the point where the load associated with the rotation increases, without going through the step of pressurizing the second joint pipe 14. Furthermore, the order of the first and second steps described above may be reversed. That is, the first step may be performed first, followed by the second step, or the second step may be performed first, followed by the first step.

[0033] Next, as the third step (rotation reference point setting step), the magnet rotor 55 is installed. In this step, as shown in Figure 4(B), the bush 57 and the rotor shaft 54 ​​are aligned in the direction of axis L, and the magnet rotor 55 is installed in the direction of axis L from top to bottom. At this time, as shown in Figure 4(A), the magnet pin 55d of the magnet rotor 55 is made to contact the claw portion 29a of the slider 29 located at the lowest end position in the circumferential direction. When this step is completed, the needle valve 42 is positioned at the valve closing reference point, and the magnet rotor 55 is positioned at the rotation reference point, which is the lowest end position when the electric valve 1 is in use (the point where it reaches the other end in the direction of axis L). Then, in this state, the next fourth step (pressure jig setting step) is performed. In the fourth step, as shown in Figure 5(B), the press jig 60 is installed on the magnet rotor 55. At this time, the position of the retaining jig 60 is adjusted so that the magnetic rotor 55 fits into the first fitting recess 65 of the retaining jig 60. Also, as shown in Figure 5(A), the position of the retaining jig 60 is adjusted so that the setting stopper 55c of the magnetic rotor 55 is inserted through the setting stopper guide 64 of the retaining jig 60.

[0034] Next, the fifth step (receiving jig 70 setting step) is performed. In the fifth step, the receiving jig 70 is attached as shown in Figure 6(B). At this time, the cylindrical part 13 of the valve body 10 is fitted into the second fitting recess 74 of the receiving jig 70. Then, the sixth step (fixing step) is performed. In this step, as shown in Figure 7(B), a load is first applied to the pressing jig 60 from the top to the bottom. At this time, the pressing load on the pressing jig 60 is transmitted to the magnet rotor 55 which is in contact with the lower surface of the pressing jig 60, then from the magnet rotor 55 to the rotor shaft 54, and then in the order of the male screw 58, female screw 27, guide member 20, fixing bracket 24, valve body 10, receiving jig 70, and elastic part 73 of the rotor shaft 54. As a result, the elastic part 73 of the receiving jig 70 flexes, and the reaction force of the elastic part 73 presses the magnet rotor 55 against the pressing jig 60, fixing the position of the magnet rotor 55.

[0035] In this state, as described above, the pressing load applied to the pressing jig 60 is transmitted to the receiving jig 70, so the rotor shaft 54 ​​becomes so-called free, and is able to rotate around axis L and move forward and backward in the direction of axis L. Then, in this state, as shown in Figure 7(B), the upper end of the rotor shaft 54 ​​is held by the gripping member 80, and only the rotor shaft 54 ​​is rotated counterclockwise by a predetermined rotation angle (a predetermined set amount). That is, with the magnet rotor 55 pressed down by the pressing jig 60, the rotor shaft 54 ​​is rotated counterclockwise (in the direction of valve opening on one side around axis L) relative to the magnet rotor 55, the guide member 20, the main valve body 30, and the valve body 10.

[0036] As a result, the rotor shaft 54 ​​moves upward, the sub-valve port 34a opens, and at zero pulse (0 pls), which is the rotation reference point of the magnet rotor 55, the magnet rotor 55 is positioned at the lower end, and an electric valve 1 can be obtained in which the needle valve 42 does not seat on the sub-valve seat 34. The predetermined setting amount, which is the relative rotation angle between the rotor shaft 54 ​​and the magnet rotor 55, can be set appropriately according to the intended use of the electric valve 1. Then, while maintaining this predetermined setting amount, the rotor shaft 54 ​​and the magnet rotor 55 are joined to each other by welding or the like, as shown in Figure 8(B). In Figure 8(B), the symbol M indicates the welding location. With this configuration, regardless of the predetermined set amount set for the relative rotation angle of the rotor shaft 54 ​​and the magnet rotor 55, as described above, with the needle valve 42 set as the valve closing reference point and the magnet rotor 55 set as the rotation reference point, the rotor shaft 54 ​​is rotated relative to the needle valve 42 by a predetermined set amount, and the rotor shaft 54 ​​and the magnet rotor 55 are joined to each other while maintaining that predetermined set amount. Therefore, variations in the predetermined set amount are less likely to occur. As a result, variations in flow rate during zero pulses can be reduced.

[0037] Furthermore, when the rotor shaft 54 ​​rotates, the upper end surface of the receiving portion 54b of the rotor shaft 54 ​​contacts the lower end surface of the bush 57. However, as shown in Figure 8(B), the contact area between the lower surface of the retaining jig 60 and the upper surface of the magnet rotor 55 is larger than the area of ​​this contact portion. Therefore, the magnet rotor 55 is prevented from rotating along with the rotor shaft 54. In addition, even if the magnet rotor 55 rotates slightly along with the rotor shaft 54, as shown in Figure 8(A), a small gap is formed between the outer circumferential surface of the setting stopper 55c formed on the magnet rotor 55 and the inner circumferential surface of the setting stopper guide 64 formed on the retaining jig 60. Therefore, the setting stopper 55c is prevented from contacting the inner circumferential surface of the setting stopper guide 64 and stress is prevented from being applied to the setting stopper 55c, thus preventing damage to the setting stopper 55c.

[0038] Finally, the eighth step (case mounting step) is performed. In this step, the case 17 is attached to the valve body 10 and fixed to the valve body 10 by welding or the like. At this time, as shown in Figure 9(A), the position of the case 17 is adjusted so that the recessed direction of one of the dimples 18 of the case 17 is parallel to the extending direction of the contact surfaces of the lower end stopper 28a surface 28b and the claw portion 29a surface 29b of the slider 29. This makes it possible to determine the position of the stator coil 56, which is fixed to the case 17 via the protrusion that fits into the dimple 18, relative to the lower end stopper 28a without variation.

[0039] As described above, according to the embodiment described, the relative rotation angle between the rotor shaft 54 ​​and the magnet rotor 55 can be set to a predetermined amount by a relatively simple assembly process in which the rotor shaft 54 ​​is positioned at the valve closing reference point, the magnet rotor 55 is positioned at the rotation reference point, and the magnet rotor 55 is held down by the pressing jig 60, and the rotor shaft 54 ​​is rotated relative to the magnet rotor 55, guide member 20, main valve body 30, and valve body 10 in the valve opening direction. Therefore, by rotating the rotor shaft 54, which is located at the valve closing reference point, by a predetermined amount, the valve opening degree when the sub-valve port 34a changes from a closed state to an open state can be kept constant, and the flow rate variation of minute flow rates during zero pulses can be easily reduced. Thus, an electric valve 1 can be provided in which the valve opening degree of the sub-valve port 34a can be set to a predetermined valve opening degree by a relatively simple assembly process, thereby reducing the flow rate variation during zero pulses and improving the controllability of the minute flow rate range.

[0040] Although embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and any design changes, etc., that do not depart from the spirit of the present invention are also included. [Explanation of Symbols]

[0041] L axis 1. Electric valve 10 Valve body 11 Main valve chamber 16 Main valve port 17 cases 20 Guide members (support members) 30 Main valve body 34a Sub-valve port 40 Auxiliary valve 54 Rotor shaft 55 Magnet Rotor 56 Stator Coil 60 Pressing jig

Claims

[Claim 1] A method for manufacturing an electric valve comprising: a cylindrical valve body having a main valve chamber and a main valve port; a main valve body provided to open and close the main valve port and having a sub-valve port inside; a sub-valve body positioned close to or away from the sub-valve port; a rotor shaft provided to be rotatable about an axis and driving the sub-valve body to move back and forth in the axial direction; a support member supporting the rotor shaft; a magnet rotor rotating about an axis together with the rotor shaft; a case mounted on the valve body and housing the magnet rotor; and a stator coil mounted on the valve body and surrounding the magnet rotor, wherein the electric valve is manufactured using a pressing jig that presses the magnet rotor from one side to the other in the axial direction, With the case and stator coil not attached to the valve body, the sub-valve body is seated in the sub-valve port, and a valve closing reference point setting step is set, which is the point at which the sub-valve port switches from an open state to a closed state. A rotation reference point setting step, which sets the rotation reference point of the magnet rotor, which is the point at which the magnet rotor reaches the other end in the axial direction, The system includes a fixing step of fixing the rotor shaft and the magnet rotor to each other, A method for manufacturing an electric valve, characterized in that, in the fixing step, the rotor shaft set as the valve closing reference point in the valve closing reference point setting step and the magnet rotor set as the rotation reference point in the rotation reference point setting step are, with the magnet rotor pressed down by the pressing jig, the rotor shaft is rotated relative to the magnet rotor, the support member, the main valve body and the valve body in the valve opening direction on one side of the axis, the relative rotation angle between the rotor shaft and the magnet rotor is set to a predetermined amount, and the magnet rotor and the rotor shaft are fixed to each other while maintaining the predetermined amount.

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