JP5773834B2 - Motorized valve - Google Patents

Description

  The present invention relates to a motor-operated valve suitable for use in a refrigeration cycle such as an air conditioner, for example, a motor-operated valve including a pilot valve body that can arbitrarily and finely adjust a valve opening (opening area). .

  Conventionally, as a pilot type control valve provided with a pilot valve body as this type of electric valve, a main valve and an electric pilot valve are provided, and the main valve includes a valve body in which a valve chamber into which fluid is introduced and led is formed; A piston-type main valve body having a reverse-convex-shaped cross section having a large-diameter portion and a small-diameter portion that are slidably inserted into the valve main body and open and close a main valve port provided in the valve main body. The electric pilot valve includes a defining member that is mounted so as to close the upper surface opening of the valve body and defines a back pressure chamber between the main valve body, and a pilot valve port provided in the main valve body The main valve is provided with a pressure equalizing passage that communicates the valve chamber and the back pressure chamber, and the main valve body is always urged in the valve opening direction by a compression coil spring. And the main valve body in the valve opening direction so as to follow the movement of the pilot valve body in the valve opening direction. Being adapted to the dynamic (e.g., see Patent Document 1).

  In addition, in a conventional electric flow control valve having a general main valve and a pilot valve, when a driving pulse of a rank phase is supplied to a stepping motor, the lift amount of the valve body increases in proportion to the number of supply pulses, and the valve body By increasing the distance between the valve body and the valve seat, the passage flow rate can be increased. Conversely, by supplying a drive pulse in the opposite phase, the lift amount of the valve body is reduced, and the passage flow amount between the valve body and the valve seat is reduced. Is decreasing.

JP 2008-64301 A

  By the way, the pilot type control valve having the above structure has a structure in which when the main valve is fully closed, the main valve is pressed in the closing direction by the pilot valve, and the main valve back pressure depends on the pilot part spring. . Further, the main valve opening point depends on the pressure on the primary side, and the main valve operation depends on the pilot portion. For this reason, the pressure balance may be lost immediately after the valve is opened, and chattering may occur where the main valve vibrates.

  Furthermore, in a conventional electric flow control valve having a main valve and a pilot valve, if the gradient of the valve opening and the lift amount is large as one control pattern, the pressure equalization time is shortened, and the control time can be shortened. Yes, but the resolution of the flow rate control is reduced, and fine control is not possible. Further, if the gradient of the valve opening degree and the lift amount is reduced as another pattern, the resolution of the flow rate control can be increased, but there is a problem that the pressure equalizing time becomes long and the control time becomes very long.

  The present invention has been made in view of such problems, and an object thereof is to provide an electric valve capable of preventing chattering immediately after the main valve is opened. It is another object of the present invention to provide an electric valve capable of reducing the control time for controlling opening and closing of the main valve and capable of controlling the flow rate with increased resolution.

  In order to achieve the above object, an electric valve according to the present invention basically includes a valve housing, a main valve body that is movably supported by the valve housing and opens and closes a main port of the valve housing, and the valve housing. And a pilot valve body that opens and closes a pilot port formed in the main valve body, and includes an electric motor that drives the pilot valve body and the main valve body to open and close. A pilot valve drive mechanism that transmits the rotation of the rotor of the electric motor to the pilot valve body; and a main valve drive mechanism that transmits the rotation of the electric motor to the main valve body. The movement amount per rotation of the rotor of the electric motor is set larger than the movement amount per rotation of the rotor of the electric motor of the main valve drive mechanism.

  In the electric valve of the present invention configured as described above, when the main valve body and the pilot valve body are controlled by the electric motor, the movement amount of the pilot valve drive mechanism is set larger than the movement amount of the main valve drive mechanism. When the electric motor is driven, first, the pilot valve body leaves the pilot port to release the pressure. Then, the main valve body is forcibly detached from the main port by the electric motor in order to adjust the flow rate in a state where the differential pressure across the main valve body is small. It does not depend on the pressure difference between the front and rear. Thereby, chattering of the main valve body can be prevented. In addition, the amount of movement of the main valve element is set smaller than the amount of movement of the pilot valve element, so the time required to reduce the pressure difference across the main valve element (ie, the time required to open the main valve element) is shortened. It is possible to control the flow rate with high resolution.

  As a preferred specific mode of the electric valve according to the present invention, the main valve driving mechanism and the pilot valve driving mechanism are a screw feed mechanism that converts rotation of the electric motor into linear motion, and the pilot valve The screw feed pitch of the valve drive mechanism is set larger than the screw feed pitch of the main valve drive mechanism. According to this configuration, the pilot valve body is opened first with a large screw feed pitch of the pilot valve screw feed mechanism, and the main valve body is opened later with a small screw feed pitch of the main valve screw feed mechanism. When the valve element is opened, the differential pressure is reduced and chattering of the main valve element can be prevented. Further, since the screw feed amount of the main valve body is small, fine control is possible.

  Furthermore, as another preferable specific embodiment of the electric valve according to the present invention, the main valve drive mechanism includes a rotor shaft coupled to the rotor, and the main valve that moves following the rotor shaft. And the main valve body is connected to the rotor shaft body with a play gap. According to this configuration, the pilot valve body opens first to reduce the differential pressure, and the main valve body moves behind the pilot valve body by the rotor shaft body connected with a play gap. The chattering of the main valve body can be reliably prevented.

  In addition, as another preferable specific specific aspect of the electric valve according to the present invention, the pilot valve drive mechanism includes a groove portion formed in the rotor axial direction on the inner peripheral side of the rotor, and the pilot valve body as a rotor shaft. A valve holder that moves in a direction, and an interlocking arm that extends from the valve holder engages with the groove. According to this configuration, the rotor and the valve holder can be interlocked with a simple configuration, and the operation can be stabilized.

  In the electric valve of the present invention, both the pilot valve body and the main valve body are driven by two drive mechanisms using one electric motor, and the movement amount of the pilot valve body is set larger than the movement amount of the main valve body. Since the pilot valve body is first opened and then the main valve body is opened, the main valve can be controlled with the pilot valve body reducing the pressure difference before and after the main valve. As a result, chattering due to pressure fluctuations when the main valve element is opened can be prevented, and a low-torque motor can be used as the motor for driving the electric valve. Furthermore, since the movement amount of the pilot valve element is increased, the pressure equalizing time can be shortened and the control time can be shortened. Furthermore, since the amount of movement of the main valve element is small, fine flow rate control can be performed.

The longitudinal cross-sectional view which shows one Embodiment of the motor operated valve which concerns on this invention, and shows a pilot valve in a closed state and a main valve is also in a closed state. The cross-sectional view which follows the AA line of the motor operated valve shown in FIG. The longitudinal cross-sectional view which shows a pilot valve in an open state and a main valve in a closed state of the electric valve shown in FIG. The longitudinal cross-sectional view which shows a pilot valve in an open state and a main valve in an open state of the electric valve shown in FIG. It is a graph with which it uses for description of operation | movement of the motor operated valve shown in FIGS. 1-4, and shows the relationship between the lift amount of the rotor 11, the pilot valve body 13a, and the main valve body 20, and valve opening degree (pulse number).

  Hereinafter, one embodiment of a motor-operated valve according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view of a main part of a motor-operated valve according to the present embodiment when the pilot valve is closed and the main valve is also closed. FIG. 2 is a horizontal sectional view taken along line AA in FIG. 3 is a vertical cross-sectional view of the main part when the pilot valve is open and the main valve is closed, FIG. 4 is a vertical cross-sectional view of the main part when the pilot valve is open and the main valve is open, and FIG. It is a graph provided for operation | movement description of a motor operated valve, and shows the relationship between the lift amount of the rotor 11, the pilot valve body 13a, and the main valve body 20, and the valve opening degree (pulse number).

  1 to 5, the motor-operated valve 1 is suitable for distribution between an outdoor unit and an indoor unit in an air conditioner such as a multi air conditioner, and is an electric pilot type as a model. It consists of a valve 2 and an electric pilot valve 3 provided on the upper side of the main valve 2. The motor-operated valve 1 includes a valve housing body 5, a tubular member 6 connected to the upper portion of the valve housing body 5 by welding or the like, and a lid-like member 7 connected by welding or the like to close the upper opening of the tubular member 6. It has the valve housing 4 which consists of these.

  The cylindrical member 6 is made of a non-magnetic metal plate such as stainless steel, and is hermetically joined to the valve housing body 5 and the lid-like member 7. A valve chamber 8 is formed inside the valve housing body 5, an inlet port 9 communicating with the valve chamber 8 is connected to the side, and an outlet port 10 communicating with the valve chamber 8 is connected to the bottom. . The refrigerant introduced from the inlet port 9 is led out from the outlet port 10 by controlling the flow rate with the main valve 2 and the pilot valve 3.

  The rotor 11 constituting the electric motor M rotates in the valve housing body 5 constituting the valve housing 4, the tubular member 6, and the upper internal space of the lid-like member 7, that is, the space surrounded by the tubular member 6. It can be rotated around the axis O and can be moved up and down. The rotor 11 is formed in a bottomed cylindrical shape having an open top, and a rotor shaft body 12 is fitted and fixed to the bottom surface of the rotor, and the rotor 11 and the rotor shaft body 12 are connected. A large number of magnetic poles are formed on the outer cylindrical portion of the rotor 11.

  The rotor shaft body 12 is formed in a bottomed cylindrical shape having an opening at the bottom, and a valve shaft 13 having a pilot valve body 13a of the pilot valve 3 at the lower end can move up and down relative to the valve housing 4 at the upper portion of the rotor shaft body 12. And is rotatably arranged. The electric motor M is a stepping motor including a stator (not shown) mounted on the outer peripheral side of the cylindrical member 6 constituting the valve housing 4 and a rotor 11 that is rotatably located inside the valve housing 4. In this case, a device that is rotated by a drive pulse supplied from a power supply circuit (not shown) is used, and the rotation angle is set by the number of drive pulses.

  The rotor shaft body 12 is rotatably fitted in a drive hole 5a penetrating the upper portion of the valve housing body 5 so as to be slidable in the vertical direction. A female screw 5b is formed in the lower half of the inner peripheral surface of the drive hole 5a, and a male screw 12a formed in the lower half of the outer peripheral surface of the rotor shaft body 12 is engaged with the drive hole 5a. Accordingly, when the rotor 11 is rotated by energizing the stator of the electric motor M (not shown), the rotor shaft body 12 fixed integrally with the rotor 11 also rotates, and the rotor shaft is engaged by the meshed female screw 5b and male screw 12a. The body 12 and the rotor 11 are configured to be movable in the vertical direction. A main valve screw feed mechanism 17 is constituted as a main valve drive mechanism by the female screw 5b on the fixed side of the valve housing body 5 and the male screw 12a on the moving side of the rotor shaft body 12.

  The lid-like member 7 fixed to the upper part of the valve housing 4 is formed with a concave portion 7a on the lower surface, and a bottomed cylindrical valve feed cylinder 15 having a lower opening is fixed to the concave portion by welding or the like. A female screw 15 a constituting a mechanism for moving the valve shaft 13 of the pilot valve 3 is formed on the inner peripheral surface of the valve feed cylinder 15. A bottomed cylindrical valve holder 16 that opens downward is positioned inside the valve feed cylinder 15, and a male screw 16 a formed on the outer circumference of the valve holder 16 is an inner circumference of the valve feed cylinder 15. Is engaged with the female screw 15a. A pilot valve screw feed mechanism 14 as a pilot valve drive mechanism is configured by the male screw 16a on the moving side of the valve holder 16 and the female screw 15a on the fixed side of the valve feed cylinder 15.

  The valve holder 16 has a through hole formed at the center of the upper surface, and a valve shaft 13 constituting the pilot valve 3 is rotatably fitted in the through hole. A push nut 18 is press-fitted and fixed to the upper end of the valve shaft 13. The valve shaft 13 and the valve holder 16 are connected. A compression coil spring 19 is compressed between the stepped portion above the valve shaft 13 and the upper inner surface of the valve holder 16 to urge the valve shaft 13 downward. The valve holder 16 is formed with an interlocking arm 16b projecting from the lower end to the outer peripheral side, and the tip of the interlocking arm 16b extends into a key groove 11a that extends in the vertical direction on the inner peripheral surface of the rotor 11. With this configuration, when the rotor 11 rotates about the valve shaft 13 (rotation axis O), the valve holder 16 is rotated following the rotor 11 by the interlocking arm 16b, and the male screw 16a on the outer periphery of the valve holder 16 and the valve feed cylinder are rotated. The valve holder 16 is configured to be movable up and down by an internal thread 15 a on the inner periphery of the body 15.

  An upper stopper body 11b on the moving side protrudes from the lower surface of the rotor 11, and has the same circumferential shape so as to be able to come into contact with the lower stopper body 5c on the fixed side protruding upward from the upper surface of the valve housing body 5. Has been placed. The rotor 11 is rotated and moved up and down, and the upper stopper body 11b of the rotor 11 is brought into contact with the lower stopper body 5c of the valve housing body 5, so that the downward movement of the rotor 11 is restricted, and the drive pulse is applied to the electric motor M. Even if is supplied, the rotation of the rotor 11 is forcibly stopped. Further, the height of the stopper bodies is set so that the upper stopper body 11b is separated from the lower stopper body 5c when the rotor 11 makes one rotation from the state where the stopper bodies are in contact with each other.

  In the valve chamber 8 inside the valve housing body 5, a main valve body 20 constituting the main valve 2 is disposed so as to be slidable in the vertical direction along the rotation axis O. The main valve body 20 includes a central shaft portion 20A formed with a pilot passage 21 penetrating the center in the vertical direction, a main valve portion 20B formed in a disc shape from the lower end portion of the central shaft portion 20A, and a central shaft portion. The interlocking flange 20C is formed to extend in the horizontal direction from the upper end of 20A, and the central flange 20D is formed to extend in the horizontal direction from the center of the central shaft portion 20A.

  The main valve portion 20B at the lower end of the main valve body 20 comes into contact with the valve seat portion 5d (main port) of the valve housing body 5 to close the main valve 2, and the main valve body 20 moves upward to move the valve seat portion 5d. The flow rate is adjusted by changing the gap. The pilot passage 21 penetrating the central shaft portion 20A of the main valve body 20 is formed with a step portion with an inclined surface of, for example, about 45 degrees so that the upper portion is a large diameter portion at the middle portion. It functions as a valve seat portion 21a (pilot port) with which the lower end of the valve shaft 13 (that is, the pilot valve body 13a) contacts and separates. A communication hole 22 penetrating in the horizontal direction is formed in the central shaft portion 20A between the interlocking flange portion 20C at the upper end of the main valve body 20 and the intermediate central flange portion 20D, and communicates with the pilot passage 21.

  The interlocking flange 20C at the upper end of the main valve body 20 is located in the internal space of the lower opening of the rotor shaft body 12, and when the main valve 2 is closed as shown in FIG. An opposing interlocking ring 23 having a play gap C is fitted into the lower end portion of the rotor shaft body 12 in a press-fitted state. The play gap C has a function of delaying the movement of the main valve provided in the path for transmitting the feed amount of the main valve screw feed mechanism 17, and the main valve body 20 has a play gap C to provide a rotor shaft. Connected to the body 12. The inner periphery of the interlocking ring 23 has a slight gap from the central shaft portion 20A of the main valve body 20, and the main valve body 20 can rotate with respect to the interlocking ring 23 and can slide up and down. A compression coil spring 24 is mounted between the upper end surface of the main valve body 20 and the upper surface of the rotor shaft body 12 to urge the main valve body 20 downward.

  The upper portion of the valve chamber 8 where the main valve body 20 is located is formed with a small diameter with respect to the valve chamber 8, and the central flange 20D of the main valve body 20 has a slight gap on the inner peripheral surface of this small-diameter upper space. Facing each other. The central collar 20D divides the upper space of the valve chamber 8 to define a back pressure chamber 25. That is, when the main valve 2 is closed as shown in FIG. 1, the valve chamber 8 is defined by the main valve portion 20 </ b> B and the central collar portion 20 </ b> D at the lower end of the main valve body 20, and the upper end of the main valve body 20. A back pressure chamber 25 is defined by the interlocking collar part 20C and the central collar part 20D. A pressure equalizing hole 26 is passed through the central flange 20D of the main valve body 20 in the vertical direction to communicate the valve chamber 8 and the back pressure chamber 25 with each other. The communication hole 22 penetrating horizontally through the central shaft portion 20A of the main valve body 20 has a function of introducing a fluid such as a refrigerant in the back pressure chamber 25 into the pilot passage 21 when the pilot valve 3 is opened. ing.

  In the electric valve 1 according to the embodiment of the present invention, the main valve 2 and the pilot valve 3 are driven by one electric motor M. The main valve 2 drives the main valve body 20 by a main valve screw feed mechanism (main valve drive mechanism) 17 comprising a male screw 12 a of the rotor shaft body 12 and a female screw 5 b of the valve housing body 5. The pilot valve 3 has a pilot valve body 13a with a pilot valve screw feed mechanism (pilot valve drive mechanism) 14 comprising a male screw 16a on the outer periphery of the valve holder 16 and a female screw 15a on the inner periphery of the valve feed cylinder 15. The valve shaft 13 is driven.

  The screw feed pitch of the pilot valve screw feed mechanism 14 is set to be larger than the screw feed pitch of the main valve screw feed mechanism 17. In the present embodiment, the screw feed pitch of the pilot valve screw feed mechanism 14 is set to 0.8 mm, and the screw feed pitch of the main valve screw feed mechanism 17 is set to 0.6 mm. For this reason, the valve shaft 13 of the pilot valve 3 is raised and lowered by 0.8 mm by one rotation of the electric motor M, and the main valve body 20 of the main valve 2 is raised and lowered by 0.6 mm. The movement amount of the pilot valve 3 is increased with respect to the movement amount. As described above, the amount of movement of the pilot valve body 13a in the vertical direction per rotation of the rotor 11 is set larger than the amount of movement of the main valve body 20 in the vertical direction.

  The operation of the motor-operated valve 1 of the present embodiment configured as described above will be described below. FIG. 1 shows a state in which the main valve 2 and the pilot valve 3 are closed, the main valve body 20 is in contact with the valve seat portion 5d of the valve housing body 5, and the fluid such as the refrigerant introduced from the inlet port 9 is It enters the valve chamber 8 and is not led out to the outlet port 10, and the pilot valve body 13 a of the pilot valve 3 is in contact with the valve seat portion 21 a and closed. Further, the upper stopper body 11b of the rotor 11 and the lower stopper body 5c of the valve housing body 5 are in contact with each other, and the rotor 11 is mechanically locked.

  When this state is described in detail, the main valve 2 and the pilot valve 3 are in a closed state, and the main valve portion 20B of the main valve 2 is in a closed state in contact with the valve seat portion 5d (main port), The pilot valve body 13a of the pilot valve 3 is in contact with the valve seat portion (pilot port) 21a of the pilot passage 21 located at the center of the main valve body 20, and is in a closed state. Then, the high-pressure refrigerant in the valve chamber 8 enters the back pressure chamber 25 through the pressure equalizing hole 26, and the differential pressure between the back pressure chamber 25 (and the valve chamber 8) and the outlet port 10 (difference before and after the main valve body 20). Pressure) and the elastic force of the compression coil spring 24 press the main valve 2 against the valve seat 5d.

  First, the operation from the state before the stopper bodies in the previous state in which the upper stopper body 11b and the lower stopper body 5c in FIG. 1 are in contact with each other will be described. From the state in which the main valve 2 and the pilot valve 3 are both closed and the upper stopper body 11b and the lower stopper body 5c are not in contact with each other, the electric motor M is supplied with pulses, for example, in the order phase, so that the rotor 11 , The rotor shaft body 12 and the valve holder 16 are lowered by the pilot valve screw feed mechanism 14 and the main valve screw feed mechanism 17. That is, the valve holder 16 moves downward and compresses the compression coil spring 19 by screw feed of the female screw 15a on the fixed side of the valve feed cylinder 15 and the male screw 16a on the moving side of the valve holder 16. The rotor shaft body 12 moves downward and compresses the compression coil spring 24 by screw feed of the female screw 5b on the stationary side of the valve housing body 5 and the male screw 12a on the moving side of the rotor shaft body 12.

  At this time, the upper stopper body 11b on the moving side is not yet in contact with the lower stopper body 5c on the fixed side, and the valve holder 16 further rotates while the valve body 13a of the pilot valve 3 is seated on the pilot valve seat portion 21a. Descend. At this time, since the valve holder 16 descends with respect to the valve shaft 13 of the pilot valve 3, the descent force of the valve holder 16 is absorbed by compressing the buffering compression coil spring 19. When the compression coil spring 19 is compressed, a gap is formed between the push nut 18 fixed to the upper end of the valve shaft 13 and the valve holder 16. Further, since the rotor shaft body 12 of the main valve 2 is also lowered with respect to the valve housing body 5, the compression coil spring 24 is also compressed and the downward force is absorbed.

  Thereafter, when the rotor 11 further rotates and the valve holder 16 is lowered, the upper stopper body 11b on the moving side comes into contact with the lower stopper body 5c on the stationary side, and the valve is supplied even if pulse supply to the stator coil of the electric motor M is continued. The lowering of the holder 16 is forcibly stopped. FIG. 1 shows this state. The main valve portion 20B of the main valve body 20 is pressed against a valve seat portion (main port) 5d by a compression coil spring 24, and the valve shaft 13 of the pilot valve 3 is a compression coil. The spring 19 is pressed against the valve seat (pilot port) 21a.

  When the main valve 2 and the pilot valve 3 are in the closed state (the state shown in FIG. 1) and the stopper bodies 5c and 11b are in contact with each other (the state of the “0” pulse), the electric motor M When pulses are supplied in the opposite phase and the rotor 11 is rotated in the opposite direction, the rotation of the rotor 11 is transmitted to the pilot valve screw feed mechanism 14 and the main valve screw feed mechanism 17. That is, the rotation of the rotor 11 rotates the valve holder 16 via the interlocking arm 16b of the valve holder 16 located in the key groove 11a, and the external thread 16a on the outer periphery of the valve holder 16 constituting the pilot valve screw feed mechanism 14. Then, the valve holder 16 is raised by the female screw 15a of the valve feed cylinder 15. At this time, the lift amount of the valve holder 16 is the screw pitch 0.8 mm of the pilot valve screw feed mechanism 14 for one rotation of the rotor 11. When the rotor 11 rotates once, the upper stopper body 11b is separated from the lower stopper body 5c, and the mechanical movement restriction of the rotor 11 is released.

  When the valve holder 16 rises along the female screw 15 a of the valve feed cylinder 15 and the valve holder 16 contacts the push nut 18, the valve shaft 13 connected to the center of the valve holder 16 rises together with the push nut 18. The pilot valve body 13a at the lower end of the valve shaft 13 leaves the pilot port 21a and the pilot valve 3 opens. When the pilot valve 3 is opened, the high-pressure refrigerant in the back pressure chamber 25 passes through the communication hole 22 of the main valve body 20, passes through the pilot passage 21, and a small amount of refrigerant is led to the outlet port 10.

  The rotation of the rotor 11 is transmitted to the rotor shaft body 12, and the rotor shaft body 12 is raised by the male screw 12 a of the rotor shaft body 12 constituting the main valve screw feed mechanism 17 and the female screw 5 b of the valve housing body 5. The amount by which the rotor shaft body 12 is raised at this time is 0.6 mm of the thread pitch of the main valve screw feed mechanism 17 for one rotation of the rotor 11. However, even if the rotor shaft body 12 is raised, there is a play gap C between the interlocking ring 23 fitted to the rotor shaft body 12 and the interlocking flange portion 20C of the main valve body 20, so that the main valve body 20 does not move. Therefore, the valve seat portion 5d and the main valve portion 20B at the lower end of the main valve body 20 remain in contact with each other, and the main port of the main valve 2 remains closed.

  That is, the movement amount of the rotor shaft body 12 is not transmitted to the main valve body 20 in the path in which the rotation of the rotor 11 is linearly converted by the main valve screw feed mechanism 17 and the linear movement amount is transmitted to the main valve body 20. The movement of the main valve element is interrupted. When the rotor shaft body 12 is raised by a predetermined amount, the interlocking ring 23 and the interlocking flange portion 20C come into contact with each other, and further rotation of the rotor 11 causes the main valve body 20 to rise together with the rotor shaft body 12 and the main valve portion 20B and the valve seat portion. 5d opens, and the high-pressure refrigerant in the inlet port 9 passes through the valve seat (main port) 5d and flows to the outlet port 10.

  The rotation of the rotor 11 raises the rotor shaft body 12 by a small screw feed pitch of the main valve screw feed mechanism 17 and raises the valve shaft 13 of the pilot valve 3 by a large screw feed pitch of the pilot valve screw feed mechanism 14. As shown in FIG. 5, when the number of pulses (valve opening) becomes Ta (for example, 32 pulses), the lower end of the valve shaft 13 which is the pilot valve portion of the pilot valve 3 as the valve holder 16 moves upward. The pilot valve body 13a begins to move away from the pilot port 21a and the pilot valve 3 begins to open. As shown in FIG. 5, the valve opening in the pilot valve 3 gradually increases until the number of pulses reaches Tb (for example, 160 pulses). The refrigerant in the back pressure chamber 25 flows out to the outlet port 10 through the pilot passage 21 and the pressure in the back pressure chamber 25 is gradually reduced. At this Tb, the pressure difference is small enough to open the main valve body 20.

  As described above, when the pilot valve 3 is opened and the main valve 2 is closed, the refrigerant in the back pressure chamber 25 passes from the pilot port 21a to the pilot passage 21 and the pressure in the back pressure chamber 25 becomes low. The pressure difference with the port 10 is reduced.

  When the number of pulses (valve opening) becomes Tb and the pressure difference between the back pressure chamber 25 and the outlet port 10 becomes small, the pilot valve body 13a of the pilot valve 3 becomes a pilot valve as shown in FIG. The distance between the pilot valve 3 and the pilot port increases after a predetermined distance α from the seat 21a. Further, in the main valve 2, the clearance C between the interlocking flange portion 20 </ b> C of the main valve body 20 and the interlocking ring 23 becomes 0, and the rotation of the rotor 11 of the electric motor M is transferred to the main valve body 20 via the rotor shaft body 12. Communicated. For this reason, the main valve body 20 is raised at a pitch of 0.6 mm by the main valve screw feed mechanism 17 by the drive pulse after the idle gap C becomes 0, and starts to open away from the valve seat portion 5d.

  When the main valve 2 is opened, the differential pressure between the main valve body 20 (the differential pressure between the back pressure chamber 25 and the outlet port 10) is reduced by the pilot valve 3 opened in advance. The valve body 20 is forcibly pulled up. Therefore, unlike the conventional control valve, the main valve is not lift-controlled by the differential pressure of the pilot valve, and the main valve body 20 is driven by the electric motor M by the main valve screw feed mechanism 17. The pressure fluctuation does not act on the main valve body 20 of the valve 2, and the chattering phenomenon is eliminated. As a result, noise generation and vibration due to chattering of the motor-operated valve 1 can be prevented.

  Subsequently, when the number of pulses supplied to the electric motor M is further increased, the pilot valve 3 is moved upward by the pilot valve screw feed mechanism 14 until the number of pulses reaches Tc (for example, 480 pulses). 20 is also moved upward by the main valve screw feed mechanism 17 as shown in FIG. Specifically, the valve shaft 13 of the pilot valve 3 is raised at a pitch of 0.8 mm by the pilot valve screw feed mechanism 14, and the main valve 2 is raised at a pitch of 0.6 mm by the main valve screw feed mechanism 17. That is, the pilot valve 3 rises ahead of the main valve 2. That is, since the electric pilot valve 3 moves with a large amount of movement, the time until the main valve body 20 can be raised is short. On the other hand, the main valve 2 rises with a small amount of movement, so fine flow control is possible. It becomes possible.

  As a result, as shown in FIG. 5, when the number of pulses (valve opening) is between Tb and Tc, the lift amount of the main valve body 20 in the motor-operated valve 1 has a gentle and constant gradient according to the number of pulses. It increases smoothly. That is, in the present embodiment, the main valve body 20 is raised at the screw feed pitch (0.6 mm) of the main valve screw feed mechanism 17 until the number of pulses changes from Tb to Tc, and the main valve body 20 The dimensional specifications and the like of each part are set so as to increase by the same distance with respect to the rotation amount). While the main valve body 20 is rising at a small feed pitch (0.6 mm), the valve shaft 13 of the pilot valve 3 is raised at a large screw feed pitch (0.8 mm). Only increasing the flow rate hardly affects the flow control of the main valve body 20.

  When the number of pulses reaches Tc, as shown in FIG. 4, the main valve body 20 reaches the maximum ascending position β, and the refrigerant having the maximum flow rate is implemented through the gap between the main valve body 20 and the valve seat portion 5d. It can pass through the motor-driven valve 1 in the form. Thus, the position of the main valve body 20 is determined by the number of drive pulses and does not depend on the pressure as in the conventional control valve. Therefore, the position of the main valve body 20 is stable and the main valve body 20 is a small screw. Since it is moved at a feed pitch (0.6 mm), flow control with high resolution becomes possible. Further, the main valve portion 20B of the main valve body 20 has a large diameter, and can pass a large flow amount of refrigerant with a small amount of movement. Further, as apparent from FIG. 5, since the pilot valve body 13a is pulled up at a high speed, the time until the differential pressure across the main valve body 20 is quickly reduced and the main valve body 20 is driven is increased. On the other hand, since the main valve body 20 is pulled up at a slower speed than the pilot valve body 13a, the flow control by the main valve body 20 can be performed precisely.

  Although not shown, the push nut 18 that fixes the valve holder 16 may abut against the surface of the valve feed cylinder 15 and function as a stopper. If the upper limit of the pilot valve 3 is thus mechanically limited, the opening area of the main valve does not become larger than the maximum opening of the main valve without limiting the pulse supplied to the electric motor M. The opening (maximum opening) at this time is maintained. The compression coil spring 24 can be omitted.

  As described above, in the electric valve 1 of the present embodiment, the pilot valve 3 and the main valve 2 are driven by one electric motor M, and the feed amount of the driving mechanism 14 of the pilot valve 3 is changed to that of the driving mechanism 17 of the main valve 2. Since it is set larger than the feed amount, the valve opening degree (opening area) can be smoothly changed according to the number of pulses supplied to the electric motor M, and the pressure equalizing time can be shortened. Therefore, the valve opening (opening area) can be adjusted arbitrarily and finely, noise generation can be effectively suppressed, and excellent responsiveness, operational stability, control characteristics, etc. can be obtained. It is done. Further, since the main valve body 20 is pulled up with the differential pressure across the main valve body 20 reduced, an electric motor having a low torque can be employed. In other words, a large flow rate can be controlled.

  Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention described in the claims. Design changes can be made. For example, the feed amount of the main valve is set to 0.6 mm and the feed amount of the pilot valve is set to 0.8 mm. However, the present invention is not limited to this, and may be arbitrarily set if the feed amount of the pilot valve is larger than the feed amount of the main valve. Can be set.

  Moreover, although the example of the screw feed mechanism was shown as a main valve drive mechanism or a pilot valve drive mechanism, as long as it is a mechanism which converts rotational motion into linear motion, another mechanism can be used. Furthermore, by setting the movement amount of the pilot valve screw feed mechanism larger than the movement amount of the main valve screw feed mechanism, the pilot valve can be opened earlier than the main valve, and the pressure difference can be reduced quickly. Therefore, chattering of the main valve body can be suppressed even if there is no idle gap that interrupts the movement of the main valve body in the path for transmitting the feed amount of the main valve screw feed mechanism.

DESCRIPTION OF SYMBOLS 1 Electric valve 2 Main valve 3 Pilot valve 4 Valve housing 5 Valve housing main body 5a Drive hole 5b Female screw 5c Lower stopper body 5d Valve seat part (main port)
6 Cylindrical member 7 Lid member 8 Valve chamber 9 Inlet port 10 Outlet port 11 Rotor 11a Key groove 11b Upper stopper body 12 Rotor shaft body 12a Male thread 13 Valve shaft 13a Pilot valve body 14 Pilot valve screw feed mechanism (pilot valve drive mechanism) )
15 Valve feed cylinder 15a Female screw 16 Valve holder 16a Male screw 16b Interlocking arm 17 Main valve screw feed mechanism (main valve drive mechanism)
18 Push nut 19 Compression coil spring 20 Main valve body 20A Central shaft portion 20B Main valve portion 20C Interlocking flange portion 20D Central flange portion 21 Pilot passage 21a Valve seat portion (pilot port)
22 communication hole 23 interlocking ring 24 compression coil spring 25 back pressure chamber 26 pressure equalization hole M electric motor C play gap

Claims (4)

A valve housing, a main valve body movably supported by the valve housing for opening and closing a main port of the valve housing, and a pilot port formed movably supported by the valve housing and formed in the main valve body An electric valve comprising an electric motor that opens and closes the pilot valve body and the main valve body,
A pilot valve drive mechanism that transmits the rotation of the rotor of the electric motor to the pilot valve body; and a main valve drive mechanism that transmits the rotation of the electric motor to the main valve body,
An electric valve characterized in that a movement amount per rotation of the rotor of the electric motor of the pilot valve drive mechanism is set larger than a movement amount of the rotor of the electric motor of the main valve drive mechanism per rotation. The main valve drive mechanism and the pilot valve drive mechanism are screw feed mechanisms that convert rotation of the electric motor into linear motion,
The motor-operated valve according to claim 1, wherein a screw feed pitch of the pilot valve drive mechanism is set larger than a screw feed pitch of the main valve drive mechanism. The main valve drive mechanism is composed of a rotor shaft connected to the rotor, and the main valve body that moves following the rotor shaft.
The motor-operated valve according to claim 1, wherein the main valve body is connected to the rotor shaft body with a play gap. The pilot valve drive mechanism includes a groove formed in the rotor axial direction on the inner peripheral side of the rotor, and a valve holder that moves the pilot valve body in the rotor axial direction,
The motor-operated valve according to any one of claims 1 to 3, wherein an interlocking arm extending from the valve holder is engaged with the groove.

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