JP2019002603A - Gas valve device - Google Patents

Abstract

To accurately regulate a gas flow rate even if hysteresis that is a rotation phase difference between when moving a valve body to the same axial position by rotating a motor forwards and when moving the valve body by rotating the motor backwards, is changed by varying play of a speed reduction gear mechanism, in a gas valve device comprising a flow rate regulation valve within a valve casing 1, the gas valve device also comprising a valve body 32 coupled to an operation rod 4 which is driven axially by a motor 5 via a speed reduction gear mechanism 51, a rotary shaft 52 and a motion conversion mechanism 6.SOLUTION: A gas valve device comprises: a detector 8 which is provided in a constituent member of the motion conversion mechanism 6 or in the operation rod 4; and a position sensor 9 which detects displacement of the detector 8 to a predetermined detection position. A difference of a rotation phase of the motor 5 is measured between when the displacement of the detector 8 to the detection position is detected by the position sensor 9 while the motor is rotated forwards and when the displacement of the detector 8 to the detection position is detected by the position sensor 9 while the motor is rotated backwards, and based on the difference, actual hysteresis is grasped.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a gas valve device in which a flow rate adjusting valve is provided in a valve casing.

  Conventionally, in this type of gas valve device, one of the valve casings has one axial direction as the forward movement direction and the other axial direction as the backward movement direction, a motor, a rotary shaft connected to the motor via a reduction gear mechanism, An operation rod driven in the forward direction and the backward direction via a motion conversion mechanism by forward and reverse rotation of the rotating shaft by forward rotation and reverse rotation, and the flow rate adjusting valve is a valve body connected to the operation rod; A valve seat provided in the valve casing and facing in the backward movement direction, and the valve body has a needle portion that is inserted into the valve hole formed in the valve seat from the backward movement direction, and the forward movement direction of the valve body In addition, there is known one in which the gas flow rate is decreased and increased by movement in the backward movement direction (see, for example, Patent Document 1).

  Here, the rotational phase of the motor when the valve body is moved to the same axial position by the forward rotation of the motor and the rotational phase of the motor when the valve body is moved by the reverse rotation of the motor are the play of the reduction gear mechanism and the motion conversion mechanism. It becomes a different phase by the influence of. Therefore, conventionally, the rotational phase difference of the motor between when the valve body is moved to the same axial position by forward rotation of the motor and when the valve body is moved by reverse rotation of the motor is calculated from design data as hysteresis, The motor is controlled when the gas flow rate is decreased based on the forward flow rate characteristic that represents the relationship between the rotational phase of the motor and the gas flow rate when the gas flow rate is decreased by moving the valve body in the forward direction. At the same time, the motor rotation phase is set by shifting the motor rotation phase in the reverse rotation direction by the amount of hysteresis relative to the flow rate characteristics during normal rotation, and the motor rotation when the valve body is moved in the backward movement direction due to motor reverse rotation. The motor is controlled to increase the gas flow rate based on the reverse flow rate characteristic representing the relationship between the phase and the gas flow rate (see, for example, Patent Document 2).

  However, the reduction gear mechanism uses a large number of gears, and the play of the entire reduction gear mechanism varies greatly from product to product due to the dimensional error of each gear. Therefore, the actual hysteresis is different from the reference hysteresis calculated from the design data. If the motor is controlled when the gas flow rate is increased based on the reverse flow rate characteristic set using the reference hysteresis, an adjustment error of the gas flow rate occurs.

JP 2013-68356 A JP 2014-1115040 A (Claim 1)

  This invention makes it the subject to grasp | ascertain an actual hysteresis and to provide the gas valve apparatus which enabled it to adjust a gas flow rate correctly in view of the above point.

  In order to solve the above problems, the present invention is a gas valve device in which a flow rate adjusting valve is provided in a valve casing, wherein one axial direction of the valve casing is a forward movement direction, and the other axial direction is a backward movement direction. A motor, a rotating shaft connected to the motor via a reduction gear mechanism, and a forward and reverse rotation of the rotating shaft by forward and reverse rotation of the motor are driven in the forward direction and the backward direction via the motion conversion mechanism. The flow control valve includes a valve body connected to the operation rod and a valve seat provided in the valve casing and facing in the reverse direction, and the valve body is a valve hole opened in the valve seat. The needle part is inserted from the backward movement direction to the valve body so that the gas flow rate decreases and increases due to the movement of the valve body in the forward movement direction and the backward movement direction. When moving by rotating and by moving the motor in reverse The normal rotation flow rate represents the relationship between the rotation phase of the motor and the gas flow rate when reducing the gas flow rate by moving the valve body in the forward movement direction by forward rotation of the motor with the rotational phase difference of the motor as the hysteresis. The motor is controlled when the gas flow rate is decreased based on the characteristics, and the valve body is recovered by reverse rotation of the motor, which is set by shifting the rotational phase of the motor in the reverse rotation direction by the hysteresis amount with respect to the flow characteristics during normal rotation. A motion conversion mechanism that controls the motor when increasing the gas flow rate based on the reverse flow rate characteristic that represents the relationship between the rotational phase of the motor and the gas flow rate when the gas flow rate is increased by moving in the moving direction. And a position sensor for detecting the displacement of the detector to a predetermined detection position. When the motor is rotating forward, the position sensor detects the detection position. The difference in the rotational phase of the motor is measured when the displacement of the child is detected and when the displacement of the detector to the detection position is detected by the position sensor during the reverse rotation of the motor. It is characterized by correcting hysteresis used for setting.

  According to the present invention, by measuring the difference between the rotational phase during forward rotation of the motor and the rotational phase during reverse rotation of the motor when the detector is displaced to the detection position, the power transmission path is greater than the member provided with the detector. The play of the part including the reduction gear mechanism located on the upstream side of the can be grasped. Therefore, even if the play of the entire reduction gear mechanism varies and the actual hysteresis differs from the reference hysteresis, the difference between the rotational phase during forward rotation of the motor and the rotational phase during reverse rotation of the motor when the detector is displaced to the detection position. Therefore, the gas flow rate can be accurately adjusted by correcting the hysteresis used for setting the flow rate characteristics during reverse rotation so as to match the actual hysteresis.

  By the way, a cylindrical cam body concentric with the operating rod, which is connected to the rotation shaft via a connector so that the operation conversion mechanism rotates in conjunction with the rotation shaft, and a helical cam formed on the cam body. An axial direction that has a pin fixed to the operating rod along a radial line passing through the axis of the operating rod and that engages with the groove, and acts via the pin from the cam groove by forward and reverse rotation of the cam body There are cases where the operating rod is constituted by a cam mechanism that moves in the forward direction and the backward direction by thrust. The cam groove is generally formed by a cam groove template that is movable in a predetermined radial direction of the cam body. In this case, because of the radial removal of the template, in the cam groove portion where the radial direction connecting the cam shaft axis and the portion does not match the die plate removal direction, the cam groove forward direction The side surfaces on the side and the backward direction side are not parallel to the radial direction, and the pins are in point contact with the side surfaces. Therefore, wear on each side surface of the cam groove is likely to occur. This wear changes the play between the cam groove and the pin, changes the actual hysteresis, and causes a gas flow rate adjustment error.

  Therefore, the cam body has an inner diameter of one of the forward direction side cylinder portion located on the forward direction side and the backward direction side cylinder portion located on the backward direction side with the cam groove being sandwiched between the outer diameters of the other. Each step of the cam groove, which is composed of end faces facing the cam grooves of the cylinder portions on the forward direction side and the backward direction side, is connected to the side surfaces on the forward direction side and the backward direction side of the cam groove. It is desirable to form the pins so that the pins are in line contact with each other in the radial direction connecting the axis of the cam body and the portion in all the longitudinal directions. According to this, each side surface of the cam groove is less likely to be worn, and the occurrence of a gas flow rate adjustment error can be suppressed. The necessity of making the cam body stepped will be described later.

The cut | disconnection side view of the gas valve apparatus of 1st Embodiment of this invention. The perspective view of the gas valve apparatus of 1st Embodiment. (A) (b) (c) The cutaway side view of the principal part which shows the action | operation of the gas valve apparatus of 1st Embodiment. The perspective view which shows the structural member and valve seat member of the motion conversion mechanism of the gas valve apparatus of 1st Embodiment. The side view which shows the relationship between the detector of the gas valve apparatus of 1st Embodiment, and a position sensor. The graph which shows the flow characteristic at the time of forward rotation, and the flow characteristic at the time of reverse rotation in the gas valve apparatus of 1st Embodiment. The cutting | disconnection side view of the gas valve apparatus of 2nd Embodiment.

  1 and 2, a gas valve device according to an embodiment of the present invention includes a tubular valve casing 1, an electromagnetic safety valve 2 disposed at a position closer to one axial direction in the valve casing 1, and a valve casing 1. A flow rate adjusting valve 3 arranged in series with the electromagnetic safety valve 2 in a portion closer to the other side in the axial direction, an operation rod 4 elongated in the axial direction of the valve casing 1 inserted from the other axial direction into the valve casing 1, and a valve A motor 5 comprising a stepping motor mounted on the outer end of the box 11 attached to the other end in the axial direction of the casing 1, a rotating shaft 52 connected to the motor 5 via a reduction gear mechanism 51, and the box 11 A motion conversion mechanism 6 that converts the rotational motion of the rotary shaft 52 into the axial motion of the operation rod 4 is provided. In the following description, one axial direction of the valve casing 1 is referred to as a forward movement direction, and the other axial direction is referred to as a backward movement direction.

  The valve casing 1 is provided with a gas inlet 1 a located on the upstream side of the electromagnetic safety valve 2 and a gas outlet 1 b located on the downstream side of the flow control valve 3. When the electromagnetic safety valve 2 is opened, the gas flows from the gas inlet 1a to the gas outlet 1b, and the gas is supplied to the burner B. The stove burner B is provided with a pan bottom temperature sensor Ba that comes into contact with the bottom surface of the cooking vessel.

  The electromagnetic safety valve 2 includes a valve seat 21 that faces in the forward direction, a valve body 22 that faces the valve seat 21, a valve spring 23 that urges the valve body 22 in the backward movement direction to be seated on the valve seat 21, and a valve An attracting piece 24 connected to the body 22 via a valve shaft 22 a extending in the forward movement direction and an electromagnet 25 facing the attracting piece 24 are provided. The valve body 22 is attracted and held at the valve open position by energizing the electromagnet 25 in a state where the valve body 22 is pushed against the valve spring 23 to the valve open position where the suction piece 24 contacts the electromagnet 25. Is done. Further, when a misfire is detected by a flame detection element (not shown) attached to the burner B, the energization to the electromagnet 25 is stopped, and the valve closing position where the valve element 22 is seated on the valve seat 21 by the valve spring 23. The electromagnetic safety valve 2 is closed by returning to, and gas outflow is prevented.

  The valve seat 21 of the electromagnetic safety valve 2 is formed on the end surface in the forward direction of the valve seat member 7 provided in the valve casing 1 and movable in the axial direction with respect to the valve casing 1. Further, the valve casing 1 includes a protrusion formed on the inner surface of the valve casing 1 that stops movement of the valve seat member 7 in the backward movement direction at a predetermined position where the valve body 22 of the electromagnetic safety valve 2 can be seated. A valve seat stopper means 71 and a valve seat biasing means 72 comprising a coil spring that biases the valve seat member 7 in the backward movement direction and elastically holds it in the predetermined position are provided. In addition, a bellophram 73 is provided to prevent the gas from flowing outside the valve seat member 7.

  The flow rate adjusting valve 3 includes a valve seat 31 that is formed on the valve seat member 7 so as to face the backward movement direction, and a valve body 32 that is fixed to the end of the operation rod 4 in the forward movement direction. The valve body 32 includes a closing valve portion 321 that can be seated on the valve seat 31 so as to close the valve hole 31a that is opened in the valve seat 31, a needle portion 322 that can be inserted into the valve hole 31a from the backward direction, and a flow rate adjustment. A bypass passage 323 that always communicates the upstream side and the downstream side of the valve 3 is provided.

  According to the above configuration, when the motor 5 is rotated forward from the state shown in FIG. 1, the operation rod 4 moves in the forward direction via the reduction gear mechanism 51, the rotation shaft 52 and the motion conversion mechanism 6. The closing valve portion 321 of the valve body 32 for the flow rate adjusting valve comes into contact with the valve seat 31 for the flow rate adjusting valve of the valve seat member 7 located at a predetermined position stopped by the valve seat stopper means 71, and thereafter the valve seat member 7 is pushed by the valve body 32 for the flow rate adjusting valve and moves in the forward movement direction, and the valve body 22 for the safety valve is pushed to the valve opening position via the valve seat member 7 (see FIG. 3A). State shown). In this state, the electromagnet 25 is energized to attract and hold the valve body 22 at the valve open position, and then the motor 5 is rotated in the reverse direction to move the operation rod 4, that is, the valve body 32 for the flow control valve in the backward movement direction. Let At this time, the valve seat member 7 follows the valve body 32 by the urging force of the valve seat urging means 72 to a predetermined position that is restrained by the valve seat stopper means 71 and moves in the backward movement direction. The electromagnetic safety valve 2 is opened when the valve 21 is separated from the valve body 22 that is adsorbed and held at the valve opening position. When the valve body 32 for the flow rate adjusting valve further moves in the backward movement direction with respect to the valve seat member 7 restrained at a predetermined position, the closing valve portion 321 is separated from the valve seat 31 for the flow rate adjusting valve, and the needle portion 322 is The gas flow rate gradually increases through the holes 31a. Thereafter, the valve body 32 for the flow rate adjusting valve moves in the forward movement direction, and is in a predetermined stroke range, that is, in a state where the valve seat member 7 is in a predetermined position that is restrained by the valve seat stopper means 71. The position where the closing valve portion 321 is seated on the valve seat 31 (the state shown in FIG. 3B), and the position immediately before the valve seat 21 for safety valve abuts on the valve body 22 for the safety valve existing at the valve opening position (FIG. 3). (C) state), the gas flows only through the bypass passage 323, and the gas flow rate is maintained at the minimum amount.

  By the way, it is difficult in terms of control to stop the stepping motor 5 at the moment when the valve element 22 for the safety valve reaches the valve opening position, that is, at the moment when the attracting piece 24 contacts the electromagnet 25. Therefore, when the operating rod 4 is pushed in the forward direction via the motion conversion mechanism 6 by further forward rotation of the motor 5 after the valve element 22 reaches the valve opening position, the contact between the attracting piece 24 and the electromagnet 25 is prevented. An excessive force may be applied to the contact portion, and the suction piece 24 may be damaged, resulting in a suction failure.

  Therefore, in the present embodiment, the motion conversion mechanism 6 is configured as follows. That is, as shown in FIG. 4, the motion converting mechanism 6 has a cylindrical shape concentric with the operating rod 4 and connected to the rotating shaft 52 via the connector 61 so as to rotate in conjunction with the rotating shaft 52. A cam body 62; and a pin 64 that is engaged with a helical cam groove 63 formed in the cam body 62 and fixed to the operation rod 4 along a radial line passing through the axis of the operation rod 4. The cam body 62 is constituted by a cam mechanism in which the operation rod 4 is moved in the forward movement direction and the backward movement direction by an axial thrust acting from the cam groove 63 via the pin 64 by forward rotation and reverse rotation of the cam body 62. .

  The connector 61 has a non-circular hole 611 that fits in the rotary shaft 52 having a non-circular cross section, and rotates together with the rotary shaft 52. Further, the connector 61 is provided with a projecting piece portion 612 that engages with a notch portion 621 formed at the end of the cam body 62 in the backward movement direction to transmit the rotational force. A guide cylinder 65 extending in the backward movement direction from the valve casing 1 is inserted into the cam body 62. The guide tube 65 is formed with a long hole 651 that is long in the axial direction, and a pin 64 is slidably engaged with the long hole 651 in the axial direction.

  The cam body 62 is movable in the axial direction, and the cam body 62 is configured by an end plate of the box 11 and stops the movement of the cam body 62 in the forward movement direction at a predetermined position. And a cam biasing means 67 comprising a coil spring for biasing in the forward movement direction. Then, the cam body 62 is cam biased by the axial reaction force acting from the pin 64 via the cam groove 63 by further forward rotation of the motor 5 after the valve body 22 for the safety valve reaches the valve opening position. It moves in the backward movement direction against the urging force of 67. According to this, even if the motor 5 is further rotated forward after the valve element 22 for the safety valve reaches the valve opening position, an excessive force is not applied to the contact portion between the suction piece 24 and the electromagnet 25, and the suction piece. It is possible to prevent an adsorption failure due to 24 scratches. Before the safety valve body 22 reaches the valve opening position, the cam body 62 is not moved in the backward movement direction due to the urging force of the valve spring 23 and the valve seat urging means 72. The urging force of the cam urging means 67 is set to be slightly larger than the resultant force of the urging forces of the valve spring 23 and the valve seat urging means 72.

  In addition, the cam body 62 has one of a forward direction side cylindrical portion 622 positioned on the forward direction side and a backward direction side cylindrical portion 623 positioned on the backward direction side with the cam groove 63 interposed therebetween, for example, forward movement This is a stepped shape in which the inner diameter of the direction side cylindrical portion 622 is equal to or larger than the outer diameter of the backward direction side cylindrical portion 623. Then, the side surfaces 631 and 632 on the forward direction side and the backward direction side of the cam groove 63 constituted by the end surfaces facing the cam grooves 63 of the respective cylindrical portions 622 and 623 on the forward direction side and the backward direction side are respectively defined. The pins 64 are formed so as to be in line contact with each other in the longitudinal direction of the cam groove 63 in parallel with the radial direction connecting the axis of the cam body 62 and the portion. According to this, unlike the case where the pin 64 makes point contact with the side surfaces 631 and 632 of the cam groove 63, the side surfaces 631 and 632 are less likely to be worn, and the occurrence of gas flow rate adjustment errors can be suppressed.

  If the cam body 62 is formed in a stepped shape as described above, a molded portion of the outer cylinder portion 622 and a molded portion of the backward cylinder portion 623 of the outer mold for molding the outer peripheral surface of the cam body 62 are formed. The side surface 631 on the forward movement direction side of the cam groove 63 is molded with the step surface between the inner circumferential surface of the cam body 62 and the molding portion of the inner cylinder forward movement side cylinder portion 622 and the backward movement direction. The side surface 632 on the backward direction side of the cam groove 63 can be formed by a step surface between the side cylinder portion 623 and the forming portion. As a result, unlike the case where the cam groove 63 is formed of a mold plate movable in the radial direction, the side surfaces 631 and 632 of the cam groove 63 are connected to the shaft of the cam body 62 in all the longitudinal directions of the cam groove 63 as described above. It can be formed so as to be parallel to the radial direction connecting the core and the part.

  Referring to FIG. 6, a line a indicates the rotation phase of the motor 5 and the gas flow rate when the valve body 32 for the flow rate adjustment valve is moved in the forward movement direction by the normal rotation of the motor 5 to reduce the gas flow rate. The forward flow rate characteristic representing the relationship is shown, and the b line represents the rotational phase of the motor 5 and the gas when the valve body 32 for the flow rate adjustment valve is moved in the reverse direction by the reverse rotation of the motor 5 to reduce the gas flow rate. The flow rate characteristics during reverse rotation representing the relationship with the flow rate are shown. Here, the rotational phase difference of the motor 5 when the valve body 32 for the flow rate adjusting valve is moved to the same axial position by the forward rotation of the motor 5 and when the motor 5 is moved by the reverse rotation of the motor 5 is defined as hysteresis H. Hysteresis H is the play of the reduction gear mechanism 51, the play between the rotating shaft 52 and the connector 61, the play between the connector 61 and the cam body 62, the play between the cam groove 63 and the pin 64, and the pin. 64 and the slot 651 correspond to the total amount of play. The reverse flow rate characteristic is obtained by shifting the rotational phase of the motor 5 in the reverse direction by the hysteresis H with respect to the normal flow rate characteristic.

  When the motor 5 is rotated forward to decrease the gas flow rate, the motor 5 is controlled based on the forward flow rate characteristic, and when the motor 5 is reversed to increase the gas flow rate, the reverse flow rate characteristic is set. The motor 5 is controlled. Specifically, in this embodiment, the gas flow rate is variably adjusted in five stages from the minimum first flow rate Q1 to the maximum fifth flow rate Q5, and is determined based on the forward flow rate characteristics. The second, third, fourth, and fifth rotation phases θ4n to θ1n corresponding to the fourth, third, second, and first flow rates Q4 to Q1 and the reverse flow rate characteristics are determined. The rotation phases θ2r to θ5r corresponding to the flow rates Q2 to Q5 are stored in the controller. Note that θ2r = θ2n−H, θ3r = θ3n−H, and θ4r = θ4n−H. When the gas flow rate is decreased to any one of the fourth to first flow rates Q4 to Q1, the motor 5 is rotated forward so that the motor 5 is stopped when the rotation phase becomes any one of θ4n to θ1n. In addition, when the gas flow rate is increased to any one of the second to fifth flow rates Q2 to Q5, the motor 5 is reversed and the motor 5 is stopped when the rotational phase becomes any one of θ2r to θ5r. To do. The motor 5 of the present embodiment is a stepping motor, and the rotational phase of the motor 5 is determined by the number of input pulses to the motor 5. Therefore, the number of pulses corresponding to each phase is input to the motor 5, and the motor 5 is rotated to each phase.

  By the way, the reduction gear mechanism 51 uses as many as 5 to 6 gears, and the play of the entire reduction gear mechanism 51 varies greatly for each product due to a dimensional error of each gear. For this reason, the actual hysteresis differs from the reference hysteresis calculated from the design data, and the motor 5 is controlled when increasing the gas flow rate based on the reverse flow rate characteristic set using the reference hysteresis. This causes an error in adjusting the gas flow rate.

  Therefore, in this embodiment, the detector 8 is provided on the cam body 62 that is a constituent member of the motion conversion mechanism 6, and the position sensor 9 that detects the displacement of the detector 8 to a predetermined detection position is provided. More specifically, the detector 8 is configured by a protrusion having a peak portion 81 that protrudes from the outer peripheral surface of the cam body 62 and rises in the backward movement direction. For example, when the motor 5 rotates forward to the rotational phase of θa in FIG. 6, the position where the detector 8 exists is set as a detection position, and the position sensor 9 is rotated when the detector 8 rotates forward to the detection position. 5, the micro switch includes a detection lever 91 that is pushed up by a peak portion 81. The output signal of the position sensor 9 is switched from OFF to ON at the moment when the detector 8 is forwardly displaced to the detection position. When the motor 5 is rotated forward to a phase exceeding the rotational phase of θa and then reversely rotated, the play of the reduction gear mechanism 51 located on the upstream side of the power transmission path with respect to the cam body 62, the rotation shaft 52 and the connector When the motor 5 reverses to the phase of θb in FIG. 6 shifted in the reverse direction from the phase of θa by the total play of the play between 61 and the play between the connector 61 and the cam body 62. Further, the detector 8 is reversely displaced to the detection position, and the output signal of the position sensor 9 is switched from on to off at the moment when the detection position is exceeded.

  When the displacement of the detector 8 to the detection position is detected by the position sensor 9 during forward rotation of the motor 5 before shipment from the factory or during maintenance, that is, the output signal of the position sensor 9 is switched from OFF to ON. When the rotational phase θa of the motor 5 and the displacement of the detector 8 to the detection position are detected by the position sensor 9 during the reverse rotation of the motor 5, that is, the output signal of the position sensor 9 is switched from on to off. The phase difference (= θa−θb) with respect to the rotational phase θb of the motor 5 is measured, and the hysteresis H used for setting the reverse flow characteristic is corrected based on this difference. Specifically, it is obtained from the design value of the total play of the play of the reduction gear mechanism 51, the play between the rotary shaft 52 and the connector 61, and the play between the connector 61 and the cam body 62. Comparing the reference value of the phase difference with the measured value of the phase difference, and adding the difference between the measured value of the phase difference and the reference value to the reference hysteresis to the hysteresis H used for setting the flow rate characteristics during reverse rotation to correct.

  According to this, even if the play of the entire reduction gear mechanism 51 varies and the actual hysteresis is different from the reference hysteresis, the hysteresis H used for setting the reverse flow characteristic is corrected to match the actual hysteresis, The gas flow rate can be adjusted accurately.

  In the first embodiment, the detector 8 is provided on the cam body 62. However, the detector 8 may be provided on the pin 64 as in the second embodiment shown in FIG. That is, in the second embodiment, the detector 8 is composed of a magnet attached to the end of the pin 64. A displacement of the detector 8 to a predetermined detection position (for example, a position when the gas flow rate becomes the fourth flow rate Q4) can be detected by a position sensor 9 including a magnetic sensor such as a Hall IC.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to this. For example, in the above-described embodiment, the detector 8 is provided on the cam body 62 and the pin 64 that are constituent members of the motion conversion mechanism 6, but the detector may be provided on the operation rod 4. Furthermore, in the gas valve device of the above-described embodiment, the electromagnetic safety valve 2 is provided in the valve casing 1 in addition to the flow rate adjusting valve 3, but the electromagnetic safety valve 2 can be omitted. The member 7 may be fixed to the valve casing 1.

DESCRIPTION OF SYMBOLS 1 ... Valve casing, 3 ... Flow control valve, 31 ... Valve seat, 31a ... Valve hole, 32 ... Valve body, 322 ... Needle part, 4 ... Operation rod, 5 ... Motor, 51 ... Reduction gear mechanism, 52 ... Rotating shaft , 6 ... motion conversion mechanism, 61 ... connector, 62 ... cam body, 622 ... forward movement side cylinder, 623 ... reverse movement direction cylinder, 63 ... cam groove, 631 ... forward direction side surface of the cam groove 632, a side surface in the backward direction of the cam groove, 64, a pin, 8 a detector, 9 a position sensor.

Claims (2)

A gas valve device in which a flow rate adjusting valve is provided in a valve casing, wherein one axial direction of the valve casing is a forward movement direction and the other axial direction is a backward movement direction, and is connected to the motor via a reduction gear mechanism. And a control rod driven in the forward and reverse directions through the motion conversion mechanism by forward and reverse rotation of the rotation shaft by forward and reverse rotation of the motor. A valve body connected to the rod and a valve seat provided in the valve casing and facing in the backward movement direction. The valve body has a needle portion that is inserted into the valve hole formed in the valve seat from the backward movement direction. The gas flow rate is decreased and increased by moving the valve body in the forward and backward movement directions, and the valve body is moved to the same axial position by the forward rotation of the motor and by the reverse rotation of the motor. The rotational phase difference of the motor As a cis, the gas flow rate is reduced based on the forward flow rate characteristic that represents the relationship between the rotational phase of the motor and the gas flow rate when the valve body is moved in the forward direction by the forward rotation of the motor to reduce the gas flow rate. The motor is controlled at the same time, and the rotational phase of the motor is shifted in the reverse direction by the hysteresis for the forward flow rate characteristics. In controlling the motor when increasing the gas flow rate based on the reverse flow rate characteristic representing the relationship between the rotation phase of the motor and the gas flow rate when increasing,
A detector provided on a constituent member of the motion conversion mechanism or the operating rod, and a position sensor for detecting the displacement of the detector to a predetermined detection position, and a detector for detecting the position at the position sensor when the motor is rotating forward The difference in rotational phase of the motor is measured when the displacement of the motor is detected and when the displacement of the detector to the detection position is detected by the position sensor during reverse rotation of the motor, and the reverse flow characteristic is set based on this difference A gas valve device that corrects hysteresis used in the process. 2. The gas valve device according to claim 1, wherein the motion conversion mechanism is connected to the rotation shaft via a connector so as to rotate in conjunction with the rotation shaft, and has a cylindrical shape concentric with the operation rod. A cam body, and a pin fixed to the operating rod along a radial line passing through the axis of the operating rod, which engages with a helical cam groove formed in the cam body, In what is composed of a cam mechanism in which the operating rod is moved in the forward direction and the backward direction by the axial thrust acting through the pin from the cam groove by reverse rotation,
The cam body is a step in which one inner diameter of the forward direction side cylindrical portion located on the forward direction side and the backward direction side cylindrical portion located on the backward direction side across the cam groove is equal to or larger than the other outer diameter. Each side surface on the forward direction side and the backward direction side of the cam groove composed of end faces facing the cam grooves of the respective cylinder portions on the forward direction side and the backward direction side is the length of the cam groove. A gas valve device characterized in that pins are formed in line contact with each other in a direction parallel to a radial direction connecting the axis of the cam body and the portion.

Images