JP2019152337A - Assembling method of electric valve - Google Patents

Abstract

To provide an assembling method of an electric valve which can exactly detect an assembling reference position when searching a control origin on the basis of a change rate of load torque, and can thereby improve the control accuracy of a flow rate or the like as much as possible.SOLUTION: In order to create a pressurized valve-closed state that a valve body 25 is pressed to a valve seat 11a by an energization force of a valve body energization spring 24, the valve body 25 is seated on the valve seat 11a by descending a valve shaft 21 while rotating it to one direction by a lift drive mechanism, after that, the valve shaft 21 is further descended to a control original position which is defined by a valve-closing direction stopper mechanism while withstanding the energization force of the valve body energization spring 24, and an assembling stopper mechanism composed of a fixed stopper 29 and a movable stopper 27 for detecting an assembling reference position in which the valve shaft 21 is further descended from the control original position by a prescribed amount is arranged between the valve body 25 and the valve shaft 21 at the assembling of the electric valve 1.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for assembling a motor-operated valve to be used by being incorporated in a heat pump type air conditioning system or the like, and in particular, a motor-operated valve of a type in which a valve body is brought into contact with or separated from a valve seat by screw feed using rotation of a rotor. The present invention relates to an assembly method.

  As this type of electric valve, even after the valve element is seated on the valve seat, the valve element is kept lowered (pressed) until the valve element biasing spring is compressed by a predetermined amount, and the valve element is fixed to the valve seat. There is known one that creates a closed valve state that is pressed with a pressing force (see, for example, Patent Documents 1 and 2).

  A conventional example of such a motor-operated valve is shown in FIG. 12, and will be briefly described below (the basic configuration is substantially the same as that of the embodiment of the present invention described later, and the details are referred to there).

  The illustrated motor-operated valve 1 ′ includes a valve body 25, a valve shaft 21 having a male screw portion 21 e that holds the valve body 25 so as to be relatively movable and relatively rotatable in the axial direction, and a valve body 25 and a valve shaft 21. A valve body provided with a valve body energizing spring 24, a guide stem 15 having a female thread portion 15i into which a male thread portion 21e of the valve shaft 21 is screwed, and a valve seat 11a to which the valve body 25 is contacted and separated. 10, a lift drive mechanism having a rotor 30 and a stator 50 for moving the valve shaft 21 up and down relative to the guide stem 15, and a valve closing direction stopper mechanism (fixed stopper) for determining the control origin position of the valve shaft 21. 55, a movable stopper 35), and in order to create a pressed closed state in which the valve element 25 is pressed against the valve seat 11a by the urging force of the valve element urging spring 24, the valve shaft 21 is integrated with the elevating drive mechanism. While rotating in the direction After the valve body 25 is lowered and seated on the valve seat 11a, the valve shaft 21 is further resisted against the biasing force of the valve body biasing spring 24, in other words, the control origin position determined by the valve closing direction stopper mechanism, in other words. The control stopper is lowered to the control origin position where the movable stopper 35 is contacted and locked to the fixed stopper 55 constituting the valve closing direction stopper mechanism.

  The operation of the motor-operated valve 1 ′ will be described more specifically.

  That is, by supplying a pulse (sometimes referred to as a forward rotation pulse) that serves as a valve closing direction drive pattern to the stator 50, the rotor 30 and the valve shaft 21 are rotated in one direction (for example, clockwise in plan view). The valve shaft 21 and the valve closing direction movable stopper 35 are rotated and lowered by the screw feed mechanism including the female screw portion 15i and the male screw portion 21e, the valve body 25 is seated on the valve seat 11a, and the valve port is closed. .

  At this time, the movable stopper 35 is not yet in contact with the fixed stopper 55, and the rotation and lowering of the rotor 30 and the valve shaft 21 are not stopped, and pulse supply is continued until the valve body biasing spring 24 is compressed by a predetermined amount. Thus, the rotor 30, the valve shaft 21, the valve holder 23 and the like are further lowered while rotating while the valve body 25 is seated on the valve seat member 11.

  At this time, since the valve shaft 21 and the valve holder 23 are lowered with respect to the valve body 25, the valve body urging spring 24 is compressed, whereby the downward force of the valve shaft 21 and the valve holder 23 is absorbed. When the compression amount of the valve body urging spring 24 reaches a predetermined amount, the movable stopper 35 comes into contact with and is locked with the fixed stopper 55, and the rotor 30 and the valve shaft 21 reach the lowest lowered position. Even if the pulse supply as the valve closing direction driving pattern is continued, the lowering of the rotor 30 and the valve shaft 21 is forcibly stopped. The position of the valve shaft 21 at this time is referred to as a control origin position, and the descending amount La from the seating position to the origin position is Po (for example, 32 pulses, which is the number of valve opening set pulses Po when converted in terms of the number of pulses. It may be called). In the motor-operated valve 1 ′ of this example, since the rotation angle by supplying one pulse in the stepping motor, the pitch of the male screw portion 21e of the valve shaft 21 and the like are known in advance, the lowering amount and the rising amount of the valve shaft 21 are closed. It can be set by counting the number of forward rotation pulses that become the valve direction drive pattern and the number of reverse rotation pulses that become the valve opening direction drive pattern.

  Thus, even after the valve body 25 is seated on the valve seat 11a and the valve port is closed, until the movable stopper 35 comes into contact with the fixed stopper 55 and is locked, By continuing the rotation and lowering of the rotor 30, the valve shaft 21, and the valve holder 23, the valve body biasing spring 24 is compressed, so that the valve body 25 is strongly pressed against the valve seat 11a (this state is pressed and closed). (Referred to as a valve state), valve leakage, etc. can be reliably prevented.

  On the other hand, when a pulse (sometimes referred to as a reverse rotation pulse) serving as a valve opening direction drive pattern is supplied to the stator 50 from the control origin position (pressed valve closed state), the rotor 30 and the valve shaft 21 are opposite to the above. The rotor 30, the valve shaft 21, the valve holder 23, and the valve-opening direction movable stopper 36 are rotated by a screw feeding mechanism that is rotated in a direction (for example, counterclockwise in plan view) and includes a female screw portion 15 i and a male screw portion 21 e. Along with this, the pressing force on the valve body 25 is weakened, the valve body biasing spring 24 expands by a predetermined amount and returns to the original set state, the valve body 25 is separated from the valve seat 11a, and the valve port is open. In this case, as shown in FIG. 8, the lift amount (valve opening = flow rate) of the valve body 25 is determined according to the number of pulses supplied to the stator 50, and when the pulse supply is continued, finally, In addition to the fully open state, the movable stopper 36 is abutted and locked to the valve-opening direction fixed stopper 56, whereby the rotation and raising of the rotor 30, the valve shaft 21, and the valve holder 23 are forcibly stopped.

  In the motor-operated valve 1 'as described above, the control origin position is accurately obtained during assembly, and the movable stopper 35 is securely contacted and locked to the fixed stopper 55 of the valve closing direction stopper mechanism at this origin position. It is required to be done.

  Therefore, in assembling the motor-operated valve 1 ′, for example, the following steps are taken.

  In this example, as shown in FIG. 13, an assembly motor 210 having the same specifications as the stepping motor having the rotor 30 and the stator 50 in the motor-operated valve 1 ′ for raising and lowering the valve shaft 21 is rotated. An assembly motor unit 200 is prepared in advance. The unit 200 includes a controller 100 with a built-in microcomputer, an operation panel 120, and the like, the hardware of which is well known, and the output shaft 220 of the assembly motor 210 is valved via a rotation transmission mechanism 240. A torque sensor 150 is connected to the shaft 21, and a torque sensor 150 for detecting a load torque applied to the valve shaft 21 is attached to the output shaft 220. A signal corresponding to the load torque of the valve shaft 21 is supplied from the torque sensor 150 to the controller 100.

  In assembling, first, as shown in FIG. 13, the guide stem 15 and the valve seat member 11 are assembled to the valve main body 10, the valve holder 23 is assembled to the valve shaft 21, and the valve body 25 is interposed between the valve body. The valve shaft assembly 20 is obtained by assembling with the bias spring 24 interposed. The valve shaft 21 (the male screw portion 21e) of the valve shaft assembly 20 is screwed into the guide stem 15 (the female screw portion 15i).

  Next, the operation panel 120 in the assembly unit 200 is operated to send a start signal to the controller 100. Then, the controller 100 executes a process as shown in the flowchart in FIG. That is, after starting, a forward rotation pulse is supplied to the assembling motor 210 in step S71 (hereinafter step is omitted), and the load torque change rate ΔT is calculated based on the signal from the torque sensor 150 in S72. Subsequently, in S73, it is determined whether or not the change rate ΔT of the load torque is greater than a predetermined threshold value α. In this step S73, it is determined that the change rate ΔT is equal to or less than the threshold value α. In the case (No), Steps S71, 72, and 73 are repeatedly executed until the rate of change ΔT exceeds the threshold value α.

  The processing here shows from the point where the number of supply pulses is 0 to the seating point in FIG. 5A, and the load torque gradually increases due to the frictional resistance or the like in the valve shaft assembly 20, but the rate of change ΔT Is usually below the threshold value α. The threshold value α is set to a value that can be exceeded when the valve shaft 21 is further lowered and the valve body biasing spring 24 is compressed even after the valve body 25 is seated on the valve seat 11a.

  In S73, when it is determined that the change rate ΔT has exceeded the threshold value α (in the case of Yes), it is determined that the valve body 25 is seated on the valve seat 11a. FIG. 14 shows the state at the time of the seating, and this seating point position is set as the assembly reference position. In the case of Yes in S73, the process proceeds to S74, the supply of the forward rotation pulse having a predetermined pulse number Po (for example, 32 pulses) is started, and the number of transmitted pulses is counted (current pulse number P ← previous pulse). Number P + 1).

  In S75, S74 is repeatedly executed until the forward rotation pulse number P reaches the predetermined pulse number Po. When the forward rotation pulse number P becomes equal to or greater than the pulse number Po, the process proceeds to S76. This program is terminated by stopping the supply of the forward rotation pulse. By supplying the number of pulses Po (for example, 32 pulses), as described above, the valve shaft 21 is used for control from the seating position (assembly reference position) as shown in FIGS. It descends to the origin position (decrease amount Lo). In this case, as shown in (1) and (2) of FIG. 7A, the length of the valve body biasing spring 24 is W1 when it is at the seating point position shown in FIG. As shown in FIG. 15, when the valve shaft 21 is lowered by Lo, the valve body urging spring 24 is compressed by Lo and its length becomes W2.

  In the state where the valve shaft 21 is at the control origin position as described above, as shown in FIG. 12, the valve closing direction movable stopper 35 is screwed into the valve shaft 21 so as to contact the valve closing direction fixed stopper 55. In addition, the rotor 30 is placed on the rotor 30 and the connecting body 32 of the rotor 30 and the small diameter portion 21b of the valve shaft 21 are fixed by welding or the like. As a result, the rotor 30 and the movable stopper 35 move up and down while rotating integrally, and when the valve shaft 21 reaches the control origin position, the movable stopper 35 is contacted and locked to the fixed stopper 55.

  Next, when the lower end portion of the can 45 is hermetically joined to the valve body 10 by welding or the like, and the stator 50 is positioned and fixed on the outer periphery of the can 45, the assembly of the electric valve 1 ′ is completed.

JP 2012-172839 A JP 2007-198372 A

  As described above, in the assembly of the conventional motor-operated valve 1 ′, it is determined whether or not the valve body 25 is seated on the valve seat 11a by comparing the rate of change ΔT of the load torque with the threshold value α. However, even if the valve element 25 is seated, the valve shaft 21 is pushed down, so that the load torque changes gently, and the seating point position where the rate of change ΔT> threshold value α is satisfied, that is, the control origin is obtained. A large error is likely to occur in the assembly reference position when performing the operation. Therefore, even if a predetermined number of pulses are applied to the motor-operated valve 1 ′, the required push valve is not closed, and a desired lift amount (= flow rate) is obtained. There was a risk that problems such as inability to obtain could occur.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to accurately detect the assembly reference position when performing the control origin search based on the rate of change of the load torque. Accordingly, it is an object of the present invention to provide a method for assembling an electric valve that can improve the control accuracy of the flow rate or the like as much as possible.

  In order to achieve the above object, an electric valve assembly method according to the present invention basically includes a valve body and a male screw portion that holds the valve body so as to be relatively movable and relatively rotatable in the axial direction. A valve stem, a valve body urging spring that is compressed between the valve body and the valve shaft, a guide stem having a female thread portion into which a male thread portion of the valve shaft is screwed, and the valve body are brought into contact with and separated from each other. A valve body provided with a valve seat, an elevating drive mechanism having a rotor and a stator for elevating while rotating the valve shaft relative to the guide stem, and a valve closing direction for determining a control origin position of the valve shaft A stopper mechanism, and the valve shaft is rotated in one direction by the lift drive mechanism so as to create a closed pressure state in which the valve body is pressed against the valve seat by the biasing force of the valve body biasing spring. After the valve body is lowered and seated on the valve seat Further, the valve shaft is lowered to the control origin position determined by the valve closing direction stopper mechanism against the urging force of the valve body urging spring. An assembly stopper mechanism comprising a fixed stopper and a movable stopper is provided between the valve body and the valve shaft for detecting a reference position for assembly that is further lowered from the control origin position by a predetermined amount. A method for assembling an electric valve, wherein the guide stem is assembled to the valve body, and the valve body is assembled to the valve shaft with the valve body biasing spring interposed therebetween. A solid body is obtained, the valve shaft of the valve shaft assembly is screwed into the guide stem, and the valve shaft is moved in one direction from a state where the valve body is separated from the valve seat by a pre-assembled motor. While rotating The rate of change of the load torque at this time is calculated, and when the rate of change of the load torque becomes larger than a predetermined threshold value, the lowering of the valve shaft is stopped, and then the valve From the seating position where the valve body on the shaft is seated on the valve seat to the design origin value until the movable stopper of the assembly stopper mechanism contacts the fixed stopper, from the seating position to the control origin position In this stop state, the rotor and the movable stopper of the valve closing direction stopper mechanism are used for the valve closing direction. It is characterized by being assembled and fixed in contact with the fixed stopper.

  In the motor-driven valve assembly method according to the present invention, an assembly stopper mechanism including a fixed stopper and a movable stopper is provided between the valve body and the valve shaft. During assembly, the valve shaft is lowered to move the movable stopper to the fixed stopper. The load torque is greatly changed, and the inflection point at which the load torque changes greatly is detected and used as the reference position for assembly. Compared to the case where the vicinity of the point is set as the assembly reference position, the control origin can be determined more accurately, and as a result, the control accuracy of the flow rate and the like can be improved as much as possible.

(A) is a longitudinal cross-sectional view which shows 1st Embodiment of the motor operated valve which concerns on this invention, (B) is A arrow directional view of (A). The longitudinal cross-sectional view which shows an initial stage set state used for description of the assembly method of the electrically operated valve shown by FIG. The longitudinal cross-sectional view which shows the assembly reference position with which it uses for description of the assembly method of the electrically operated valve shown by FIG. The longitudinal cross-sectional view which shows the origin position for control used for description of the assembly method of the motor operated valve shown in FIG. (A) is conventional, (B) is a load torque-screw feed amount relationship diagram each used for explanation of the assembly method of the motor-operated valve of the present invention. 5A is a flowchart showing an example of an origin control program for control at the time of assembly, which is provided for explaining a conventional method of assembling a motorized valve according to the present invention. (A) is conventional, (B) is a figure which is provided for description of the compression amount of a valve body urging | biasing spring of this invention, respectively. The graph which shows the relationship between the flow volume in a motor operated valve, and the number of supply pulses. The longitudinal cross-sectional view which shows 2nd Embodiment of the motor operated valve which concerns on this invention. The longitudinal cross-sectional view which shows 3rd Embodiment of the motor operated valve which concerns on this invention. The longitudinal cross-sectional view which shows 4th Embodiment of the motor operated valve which concerns on this invention. The longitudinal cross-sectional view which shows an example of the conventional motor operated valve. FIG. 13 is a longitudinal sectional view showing an initial set state, which is used for explaining the assembly method of the electric valve shown in FIG. 12. The longitudinal cross-sectional view which shows the seating position (reference | standard position for an assembly) with which it uses for description of the assembly method of the electrically operated valve shown by FIG. The longitudinal cross-sectional view which shows the origin position for control used for description of the assembly method of the electrically operated valve shown by FIG.

  Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment]
FIG. 1A is a longitudinal sectional view showing a first embodiment of the motor-operated valve according to the present invention, FIG. 1B is a view taken along arrow A (top view of the rotor) in FIG. FIGS. 4A to 4C are diagrams for explaining the assembly method (control origination) of the motor-operated valve shown in FIG.

  The illustrated motor-operated valve 1 includes a bottomed cylindrical valve main body 10 having an open top surface, a can 45 having a lower end sealed to the outer peripheral side of the upper end surface of the valve main body 10 by welding or the like, and in the upper end surface of the valve main body 10. A male stem portion 21e formed on the outer periphery of the shaft-like portion 21a is formed on the guide stem 15 with the bowl-shaped disc 18 fixed to the peripheral side by welding or the like, and the female screw portion 15i formed on the small-diameter upper portion 15b of the guide stem 15. Includes a valve shaft 21 that is screwed together, a rotor 30 that is connected and fixed to the valve shaft 21 so as to be integrally rotatable, and a stator 50 that is externally fitted to the outer periphery of the can 45 to rotationally drive the rotor 30. ing.

  Here, a stepping motor is constituted by the rotor 30 and the stator 50, and a screw feeding mechanism is constituted by the female screw portion 15i of the guide stem 15 and the male screw portion 21e of the valve shaft 21, and the stepping motor and the screw feeding mechanism are Thus, an elevating drive mechanism for elevating and lowering the valve shaft 21 is configured.

  The valve body 10 is made by pressing a metal plate material, and a valve seat member 11 having a valve seat (valve port) 11a is fixed to the bottom 10b by brazing or the like, The lower part of the guide stem 15 is inserted.

  A first inlet / outlet 6 made of a pipe joint is provided at one side of the valve chamber 12 of the valve main body 10, and a second inlet / outlet 7 made of a pipe joint is attached to the valve seat member 11 by brazing or the like. It is joined.

  The valve shaft 21 includes a small-diameter portion 21b into which the connecting body 32 of the rotor 30 is fitted, a male screw portion 21e that is screwed into the female screw portion 15i of the guide stem 15, and a hook-like portion below the male screw portion 21e. 21d and a lower connecting portion 21c with a caulking portion 21f. A ceiling hole portion of the lower end portion of the valve shaft 21 is connected and fixed to the caulking portion 21f, and the large-diameter cylindrical body portion 15a of the guide stem 15 is connected. A cylindrical valve holder 23 with a ceiling portion 23 b that is slidably inserted into the valve holder 23 is held, and an upper portion of the valve body 25 is slidably inserted into a lower portion of the cylindrical portion 23 a of the valve holder 23.

  The valve body 25 has an inverted frustoconical valve body portion 25a that is seated with its lower portion inserted into a valve seat (valve port) 11a having an inverted conical surface portion, and a cylindrical body portion that continues to the upper portion of the valve body portion 25a. In addition to having a thick retaining sleeve 25c that is externally fitted and fixed to the upper portion of the cylindrical body portion 25b by press-fitting, welding, or the like, A shaped portion 29 is provided. Here, the outer diameter of the cylindrical body portion 25b (the upper portion) inserted through the through hole of the bottom plate portion 27 fixed to the lower end portion of the valve holder 23 is larger than the diameter of the valve seat (valve port) 11a. Has also been enlarged.

  At the lower end of the valve holder 23, the valve body 25 (preventing sleeve 25 c) is made of a thick plate provided with a thin annular disk 28 sandwiched between the valve body 25 and retaining, and provided with a through hole. The bottom plate portion 27 is held and fixed by caulking, welding, or the like.

  On the other hand, a spring receiving member 26 having a hat-shaped cross-section is placed on the upper surface of the valve body 25, and the valve body pressing and serving portion is interposed between the flange-shaped portion of the spring receiving member 26 and the ceiling portion 23 b of the valve holder 23. A valve body urging spring 24 made of a compression coil spring for buffering is compressed, and the valve body 25 is always urged downward by the valve body urging spring 24.

  Here, a flange-like portion 29 provided on the valve body 25 and a bottom plate portion 27 constituting the bottom portion of the valve holder 23 provided on the valve holder 23 are respectively detected at the time of assembly described later (detects an assembly reference position). Therefore, it becomes a fixed stopper and a movable stopper of the assembling stopper mechanism (details will be described later).

  The valve shaft 21, the valve holder 23, the valve body 25, and the valve body biasing spring 24 described above rotate substantially integrally when the valve body 25 is separated from the valve seat 11a (opened state). It can be lifted up and down.

  In this case, in the valve open state (assembling initial state) as shown in FIG. 2, the retaining sleeve 25 c of the valve body 25 is engaged and locked to the bottom plate portion 27 with the annular disk 28 interposed therebetween. The lower surface of the bottom plate portion 27 and the upper surface of the hook-shaped portion 29, in other words, the movable stopper (bottom plate portion) 27 and the fixed stopper (hook-shaped portion) 29 of the assembling stopper mechanism are separated from each other by a predetermined distance Lp. (Assembling will be described in detail later).

  Further, in order to set the control origin position of the rotor 30 and the valve shaft 21, the upper surface of the small-diameter upper portion 15b of the guide stem 15 has a rectangular cross-section fixing stopper 55 having a predetermined width, height and depth. Is projecting upward, and a valve-opening direction fixed stopper 56 having a predetermined width, height, and depth is projecting downward on the upper portion of the large-diameter cylindrical body portion 15a of the guide stem 15. .

  A valve-closing direction movable stopper 35 is screwed to the upper end portion of the male screw portion 21 e of the valve shaft 21 and is locked to the disc-shaped ceiling portion of the rotor 30. The valve-closing-direction movable stopper 35 has a nut portion 35a having a hexagonal shape in plan view that is screwed into the male screw portion 21e and an arc shape on one side thereof, and a predetermined width projecting downward from the nut portion 35a. The stopper portion 35s has a rectangular section in height and depth.

  Further, a valve-opening direction movable stopper 36 that is brought into contact with and locked to the valve-opening direction fixed stopper 56 is screwed to the lower end portion of the male screw portion 21e of the valve shaft 21 so that the ceiling portion of the valve holder 23 is engaged. It is locked to 23b to prevent it from coming off. The valve-opening direction movable stopper 36 includes a nut portion 36a that is screwed into the male screw portion 21e, and a stopper portion 36s having a rectangular cross section that protrudes upward from the nut portion 36a and has a predetermined width, height, and depth. It has become.

  The rotor 30 includes a cylindrical magnet 31 with a ceiling and a coupling body 32 integrally coupled to the ceiling portion. The coupling body 32 is externally fitted to a small-diameter portion 21b of the valve shaft 21 and is closed. It is placed on the valve direction movable stopper 35 and fixed to the small diameter portion 21b by welding.

  Here, on the lower surface side of the ceiling portion of the rotor 30, as shown by a broken line in FIG. 1 (B), a concave portion 33 having a D cut portion having both ends formed in a D shape in plan view. Provided and fitted in a state in which one side of the nut portion 35a of the valve-closing-direction movable stopper 35 is in contact with an arc-shaped portion other than the D-cut portion formed in the recess 33, The other two sides of the nut portion 35a are in contact with the D-cut portion, so that the rotor 30, the valve closing direction movable stopper 35, and the valve shaft 21 rotate integrally. Can be raised and lowered.

  On the other hand, a stator 50 including a yoke 51, a bobbin 52, a coil 53, a resin mold 54, and the like is fitted on the outer periphery of the can 45. The stator 50 is positioned and fixed at a predetermined position with respect to the valve body 10 by a positioning fixture (not shown) provided at the bottom thereof.

  In addition, the motor-operated valve 1 of the present embodiment is provided with a controller incorporating a microcomputer so as to control the operation (flow rate) of the motor-operated valve 1 and the like. The controller performs necessary arithmetic processing based on signals from each sensor, operation panel (remote control), etc. arranged in the system in which the motor-operated valve 1 is incorporated, and sends a drive pulse to the stator 50 of the motor-operated valve 1. Supply.

  As a result, the rotor 30 of the motor-operated valve 1 rotates by an amount corresponding to the number of supply pulses. When the rotor 30 is rotated, the valve shaft 21 is rotated integrally therewith. At this time, the valve shaft 21 is moved up and down with the valve body 25 by the screw feed mechanism, thereby adjusting the flow rate of the refrigerant. Is done.

  The operation of the motor-operated valve 1 will be described more specifically.

  That is, by supplying a pulse (sometimes referred to as a forward rotation pulse) that serves as a valve closing direction drive pattern to the stator 50, the rotor 30 and the valve shaft 21 are rotated in one direction (for example, clockwise in plan view). The valve shaft 21 and the valve closing direction movable stopper 35 are rotated and lowered by the screw feed mechanism including the female screw portion 15i and the male screw portion 21e, the valve body 25 is seated on the valve seat 11a, and the valve port is closed. .

  At this time, the movable stopper 35 is not yet in contact with the fixed stopper 55, and the rotation and lowering of the rotor 30 and the valve shaft 21 are not stopped, and pulse supply is continued until the valve body biasing spring 24 is compressed by a predetermined amount. Thus, the rotor 30, the valve shaft 21, the valve holder 23 and the like are further lowered while rotating while the valve body 25 is seated on the valve seat member 11.

  At this time, since the valve shaft 21 and the valve holder 23 are lowered with respect to the valve body 25, the valve body urging spring 24 is compressed, whereby the downward force of the valve shaft 21 and the valve holder 23 is absorbed. When the compression amount of the valve body urging spring 24 reaches a predetermined amount, the movable stopper 35 comes into contact with and is locked with the fixed stopper 55, and the rotor 30 and the valve shaft 21 reach the lowest lowered position. Even if the pulse supply as the valve closing direction driving pattern is continued, the lowering of the rotor 30 and the valve shaft 21 is forcibly stopped. The position of the valve shaft 21 at this time is referred to as a control origin position, and the lowering amount Lo from the seating position to the origin position is Po (for example, 32 pulses, which is the number of valve-opening set pulses Po). It may be called). In the motor-operated valve 1 of this example, since the rotation angle by one pulse supply in the stepping motor, the pitch of the male screw portion 21e of the valve shaft 21 and the like are known in advance, the descending amount and the ascending amount of the valve shaft 21 are It can be set by counting the number of forward rotation pulses serving as the direction drive pattern and the number of reverse rotation pulses serving as the valve opening direction drive pattern.

  Thus, even after the valve body 25 is seated on the valve seat 11a and the valve port is closed, until the movable stopper 35 comes into contact with the fixed stopper 55 and is locked, By continuing the rotation and lowering of the rotor 30, the valve shaft 21, and the valve holder 23, the valve body biasing spring 24 is compressed, so that the valve body 25 is strongly pressed against the valve seat 11a (this state is pressed and closed). (Referred to as a valve state), valve leakage, etc. can be reliably prevented.

  On the other hand, when a pulse (sometimes referred to as a reverse rotation pulse) serving as a valve opening direction drive pattern is supplied to the stator 50 from the control origin position (pressed valve closed state), the rotor 30 and the valve shaft 21 are opposite to the above. The rotor 30, the valve shaft 21, the valve holder 23, and the valve-opening direction movable stopper 36 are rotated by a screw feeding mechanism that is rotated in a direction (for example, counterclockwise in plan view) and includes a female screw portion 15 i and a male screw portion 21 e. Along with this, the pressing force on the valve body 25 is weakened, the valve body biasing spring 24 expands by a predetermined amount and returns to the original set state, the valve body 25 is separated from the valve seat 11a, and the valve port is open. In this case, as shown in FIG. 8, the lift amount (valve opening = flow rate) of the valve body 25 is determined according to the number of pulses supplied to the stator 50, and when the pulse supply is continued, finally, In addition to the fully open state, the movable stopper 36 is abutted and locked to the valve-opening direction fixed stopper 56, whereby the rotation and raising of the rotor 30, the valve shaft 21, and the valve holder 23 are forcibly stopped.

  In the motor-operated valve 1 as described above, the control origin position is accurately obtained during assembly, and the movable stopper 35 is securely contacted and locked to the fixed stopper 55 of the valve closing direction stopper mechanism at this origin position. It is required to keep it.

  Therefore, in assembling the motor-operated valve 1, for example, the following steps are taken.

  In this example, as shown in FIG. 2, an assembly motor 210 having the same specifications as the stepping motor having the rotor 30 and the stator 50 in the motor-operated valve 1 for moving the valve shaft 21 up and down is included. An assembly motor unit 200 is prepared in advance. The unit 200 includes a controller 100 with a built-in microcomputer, an operation panel 120, and the like, the hardware of which is well known, and the output shaft 220 of the assembly motor 210 is valved via a rotation transmission mechanism 240. A torque sensor 150 is connected to the shaft 21, and a torque sensor 150 for detecting a load torque applied to the valve shaft 21 is attached to the output shaft 220. A signal corresponding to the load torque of the valve shaft 21 is supplied from the torque sensor 150 to the controller 100.

  When assembling, first, as shown in FIG. 2, the guide stem 15 and the valve seat member 11 are assembled to the valve body 10, the valve holder 23 is assembled to the valve shaft 21, and the valve body 25 is interposed between the valve bodies. The valve shaft assembly 20 is obtained by assembling with the bias spring 24 interposed. The valve shaft 21 (the male screw portion 21e) of the valve shaft assembly 20 is screwed into the guide stem 15 (the female screw portion 15i).

  Next, the operation panel 120 in the assembly unit 200 is operated to send a start signal to the controller 100. Then, the controller 100 executes processing as shown in the flowchart in FIG. That is, after starting, a forward rotation pulse is supplied to the assembling motor 210 in step S81 (hereinafter, step is omitted), and a change rate ΔT of the load torque is calculated based on a signal from the torque sensor 150 in S82. Subsequently, in S83, it is determined whether or not the change rate ΔT of the load torque is greater than a predetermined threshold value β. In this step S83, it is determined that the change rate ΔT is equal to or less than the threshold value β. In the case (No), Steps S81, 82, and 83 are repeatedly executed until the rate of change ΔT exceeds the threshold value β.

  This process shows from the point where the number of supply pulses is 0 in FIG. 5B to the assembly reference position where the assembly movable stopper 27 contacts the fixed stopper 29. Here, when the assembly movable stopper 27 is contacted and locked to the fixed stopper 29, the load torque increases at an angle close to vertical, and the rate of change ΔT of the load torque increases rapidly. Can be set to such a large value that cannot be taken when the valve body biasing spring 24 is compressed (elastically deformed). Therefore, the assembly movable stopper 27 contacts the fixed stopper 29. The reference position can be detected accurately and reliably.

  If it is determined in S83 that the rate of change ΔT has exceeded the threshold value β (in the case of Yes), the assembly movable stopper 27 has come to the assembly reference position where it is contacted and locked to the fixed stopper 29. Judge. FIG. 3 shows the state at the assembly reference position. In the case of Yes in S83, the process proceeds to S84, the supply of the reverse pulse having the predetermined number of pulses Pr is started, and the number of transmitted pulses is counted (current pulse number P ′ ← previous pulse number P ′ + 1). . Here, the reverse rotation pulse number Pr is a lowering amount Lo from the seating point position to the control origin position from the lowering amount Lp as a design value until the assembly movable stopper 27 contacts the fixed stopper 29. The number of pulses is equivalent to the subtracted return amount Lr (Lr = Lp−Lo). In this example, the descent amount Lp, the descent amount Lo, and the return amount (increase amount) Lr are preset as design values, and the descent amount Lo is converted into the number of pulses Po (for example, 32 pulses), and the descent amount Lp Is converted to a pulse number Pp (for example, 64 pulses) that is twice the descending amount Lo, that is, twice the number of pulses Po (for example, 32 pulses), and the increasing amount Lr is a pulse from the number of pulses Pp (for example, 64 pulses). It is converted into a pulse number Pr (for example, 32 pulses) obtained by subtracting the number Po (for example, 32 pulses).

  Then, in S85, S84 is repeatedly executed until the reverse pulse number P ′ reaches the return pulse number Pr. When the reverse pulse number P ′ becomes equal to or greater than the pulse number Pr, the process proceeds to S86 and the reverse pulse number is changed. Stop the supply and end this program. By supplying the reverse pulse number Pr (for example, 32 pulses), as described above, the valve shaft 21 is brought into contact with the fixed stopper 29 by the assembly movable stopper 27 as shown in FIGS. It rises from the corresponding assembly reference position to the control origin position (amount of increase Lr). In this case, as shown in (1), (2), and (3) of FIG. 5B and FIG. 7B, when in the initial set position shown in FIG. 3 and 4, when the valve shaft 21 is lowered by b = Lp as shown in FIGS. 3 and 4, the valve body biasing spring 24 is compressed by the Lp and the length thereof is increased. Is W3. Thereafter, when the valve shaft 21 is raised by Lr, the valve body urging spring 24 expands by the Lr and its length becomes W2, and the compression amount at this time is a = Lo. Note that by making the compression amount b = Lp an integral multiple of the compression amount a = Lo, it is not necessary to greatly change the jig or the like, and the conventional jig can be used as it is. Here, the compression amount b = Lp is an integral multiple of the compression amount a = Lo, but the compression amount b = Lp is larger than the compression amount a = Lo, and the valve body biasing spring 24 can maintain elasticity. It can be set freely up to the upper limit of the compression amount. For example, it is preferable to set the compression amount b = Lp between 1.5 and 3.0 times the compression amount a = Lo.

  In the state where the valve shaft 21 is at the control origin position as described above, the valve-closing direction movable stopper 35 is screwed into the valve shaft 21 and brought into contact with the valve-closing direction fixed stopper 55 as shown in FIG. In addition, the rotor 30 is placed on the rotor 30 and the connecting body 32 of the rotor 30 and the small diameter portion 21b of the valve shaft 21 are fixed by welding or the like. As a result, the rotor 30 and the movable stopper 35 move up and down while rotating integrally, and when the valve shaft 21 reaches the control origin position, the movable stopper 35 is contacted and locked to the fixed stopper 55.

  Next, when the lower end portion of the can 45 is hermetically joined to the valve body 10 by welding or the like, and the stator 50 is positioned and fixed on the outer periphery of the can 45, the assembly of the motor-operated valve 1 is completed.

  As described above, in the motor-operated valve 1 according to the present embodiment, the assembly stopper mechanism including the fixed stopper 29 and the movable stopper 27 is provided between the valve body 25 and the valve shaft 21, and the valve shaft 21 is moved during assembly. Since the movable stopper 27 is brought into contact with the fixed stopper 29 so as to greatly change the load torque, the valve shaft 21 is further moved by a predetermined amount from the control origin position based on the rate of change of the load torque. The lowered assembly reference position can be accurately and reliably detected. In this case, the lowering amount Lp, the lowering amount Lo, and the return amount (raising amount) Lr are set in advance as design values, and in combination with the fact that the assembly reference position can be accurately detected, The error is considerably smaller than in the case of detecting the inflection point of the change in load torque when the valve body 25 is seated on the valve seat 11a as in the prior art, so that the control origin can be accurately determined. As a result, the control accuracy such as the flow rate can be improved as much as possible.

[Embodiment 2]
FIG. 9 is a longitudinal sectional view showing a second embodiment of the motor-operated valve according to the present invention. In the illustrated motor-operated valve 2, the same components or the same functional parts as those of the motor-operated valve 1 of the first embodiment are denoted by the same reference numerals, and redundant description will be omitted. Only the differences will be described below.

  In the motor-operated valve 2 of the present embodiment, the valve body 65 has an inverted truncated cone-shaped valve body portion 65 a, a short columnar body portion 65 b, and an upper projecting portion 65 c, and slides on the cylindrical portion 15 a of the guide stem 15. A valve holder 60, which is movably inserted, is fixed to the upper portion of the short cylindrical body 65b of the valve body 65, and the valve shaft 21 is disposed in the valve holder 60 so that the valve shaft 21 can be relatively moved and rotated in the axial direction. It is inserted and locked to the ceiling 60b of the valve holder 60 with an annular disc 66 interposed therebetween. Further, in the cylindrical portion 60 a of the valve holder 60, the lower spring receiving member 62 that is externally fitted to the upper projecting portion 65 c of the valve body 65 and the upper spring receiver that is externally fitted and fixed to the lower connecting portion 21 c of the valve shaft 21. The valve body urging spring 24 is retracted between the member 61 and the flange 21g is provided in a portion of the valve shaft 21 located above the ceiling 60b of the valve holder 60. The assembling stopper mechanism is configured with the ceiling portion 60b as a fixed stopper and the flange portion 21g of the valve shaft 21 as a movable stopper.

  In the motor-operated valve 2 configured as described above, the separation distance between the ceiling portion 60b of the valve holder 60 serving as a fixed stopper and the flange-shaped portion 21g of the valve shaft 21 serving as a movable stopper is the first embodiment. The lowering amount Lp of the first embodiment is also set in the same manner, and the lowering amount Lo and the returning amount (raising amount) Lr of the first embodiment are similarly set. During assembly, the valve shaft 21 is lowered to attach the movable stopper 21g to the fixed stopper 60b. Since the load torque is greatly changed by contact, the assembly reference position in which the valve shaft 21 is further lowered by a predetermined amount from the control origin position is accurately and based on the rate of change of the load torque. It can be detected reliably. In this case, the lowering amount Lp, the lowering amount Lo, and the return amount (raising amount) Lr are set in advance as design values, and in combination with the fact that the assembly reference position can be accurately detected, The error is considerably smaller than in the case of detecting the inflection point of the change of the load torque when the valve body 65 is seated on the valve seat 11a as in the prior art. Therefore, as in the first embodiment, the error is The origin can be accurately determined, and the control accuracy such as the flow rate can be improved as much as possible.

[Embodiment 3]
FIG. 10 is a longitudinal sectional view showing a third embodiment of the motor-operated valve according to the present invention, in which the hook-like portion 29 provided on the valve body 25 is deleted from the first embodiment shown in FIG. An example in which a fixed stopper is formed on the spring receiving member 26 and a movable stopper is provided on the valve holder 23 is shown. In the illustrated motor-operated valve 3, the same components or the same functional parts as those of the motor-operated valve 1 according to the first embodiment are denoted by the same reference numerals and redundant description will be omitted, and only differences will be described below.

  In the motor-operated valve 3 of the present embodiment, the portion around the ceiling hole provided in the ceiling portion 23b of the valve holder 23 is extended below the caulking portion 21f, and the lower portion thereof is formed as a movable stopper. The spring receiving member 26 provided on the upper part of the spring is extended upward as compared with the first embodiment, and the upper part is formed as a fixed stopper, thereby constituting the assembly stopper.

  In the motor-operated valve 3 configured as described above, the distance between the ceiling portion 23b of the valve holder 23, which is a movable stopper, and the spring receiving member 26, which is a fixed stopper, is the lowering amount Lp of the first embodiment. The lowering amount Lo and the returning amount (raising amount) Lr of the first embodiment are also set in the same manner. At the time of assembly, the valve shaft 21 is lowered to bring the movable stopper 23b into contact with the fixed stopper 26. Since the load torque is largely changed, the assembly reference position in which the valve shaft 21 is further lowered from the control origin position by a predetermined amount based on the rate of change of the load torque, as in the first embodiment. Can be detected accurately and reliably.

[Embodiment 4]
FIG. 11 is a longitudinal sectional view showing a fourth embodiment of the motor-operated valve according to the present invention, in which the hook-shaped portion 21g provided on the valve shaft 21 is deleted from the second embodiment shown in FIG. An example is shown in which a movable stopper is formed on the upper spring receiving member 61 provided integrally with the lower end of the valve shaft 21 and a fixed stopper is provided on the lower spring receiving member 62. In the motor-driven valve of the illustrated example, the same components or the same function parts as those of the motor-operated valve 2 of the second embodiment are denoted by the same reference numerals, and redundant description is omitted. Only the differences will be described below.

  In the motor-operated valve 4 of the present embodiment, the upper spring receiving member 61 and the valve shaft 21 are integrally formed, the lower surface of the upper spring receiving member 61 is extended to the lower side, and the lower part thereof is formed as a movable stopper. A lower spring receiving member 62 provided at the upper portion of 65 is extended upward as compared with the second embodiment, and the upper portion is formed as a fixed stopper, thereby constituting the assembly stopper.

  In the motor-operated valve 4 configured as described above, the separation distance between the upper spring receiving member 61 that is a movable stopper and the lower spring receiving member 62 that is a fixed stopper is the lowering amount Lp of the first embodiment. Further, the lowering amount Lo and the returning amount (raising amount) Lr of the first embodiment are set in the same manner, and at the time of assembly, the valve shaft 21 is lowered to bring the movable stopper 61 into contact with the fixed stopper 62. Since the load torque is greatly changed, the assembly reference position in which the valve shaft 21 is further lowered from the control origin position by a predetermined amount based on the rate of change of the load torque, as in the second embodiment. Can be detected accurately and reliably.

1 Motorized valve 10 Valve body 11a Valve seat (valve port)
15 Guide stem 15i Female thread portion 20 Valve shaft assembly 21 Valve shaft 21e Male thread portion 23 Valve holder 24 Valve body biasing spring 25 Valve body 26 Spring receiving member 27 Bottom plate portion (movable stopper for assembly)
29 Hook (fixing stopper for assembly)
30 Rotor 35 Movable stopper for valve closing direction 36 Movable stopper for valve opening direction 50 Stator 55 Fixed stopper for valve closing direction 56 Fixed stopper for valve opening direction

Claims (1)

A valve body, a valve shaft having a male screw portion that holds the valve body so as to be relatively movable and relatively rotatable in the axial direction, and a valve body biasing spring that is contracted between the valve body and the valve shaft And a valve stem provided with a guide stem having a female thread part into which the male thread part of the valve shaft is screwed and a valve seat to which the valve body is contacted and separated, and ascending and descending while rotating the valve shaft with respect to the guide stem And an elevating drive mechanism having a rotor and a stator, and a valve closing direction stopper mechanism that determines a control origin position of the valve shaft, and the valve body is moved by the urging force of the valve body urging spring. In order to create a pressed valve closed state pressed against the valve body, the valve shaft is lowered while being rotated in one direction by the lift drive mechanism to seat the valve body on the valve seat, and the valve shaft is further moved to the valve The valve closing direction stop against the biasing force of the body biasing spring. It is to be lowered to the control origin position determined by the mechanism,
When assembling the motor-operated valve, an assembly stopper mechanism comprising a fixed stopper and a movable stopper for detecting an assembly reference position in which the valve shaft is further lowered by a predetermined amount from the control origin position. A method of assembling an electric valve provided between a body and the valve shaft,
The guide stem is assembled to the valve body, and the valve body is assembled to the valve shaft with the valve body biasing spring interposed therebetween, thereby obtaining a valve shaft assembly, and the valve of the valve shaft assembly The shaft is screwed into the guide stem, and the valve body is lowered while rotating the valve shaft in one direction from a state where the valve body is separated from the valve seat by a pre-assembled motor, and the load at this time When the rate of change in torque is calculated and the rate of change in load torque exceeds a predetermined threshold value, the valve shaft stops descending, and then the valve body in the valve shaft The lowering amount as a design value from the seating position to the control origin position from the lowering amount as the design value until the movable stopper of the assembly stopper mechanism comes into contact with the fixed stopper from the seating position seated on the seat. Deduct Rotate the valve in the other direction and lift it to stop it. In this stopped state, assemble the rotor and the movable stopper of the valve closing direction stopper mechanism against the valve shaft in contact with the fixed stopper for valve closing direction. A method for assembling a motor-operated valve, characterized by:

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