JP6871069B2 - Gas valve gear - Google Patents

Description

The present invention is a gas valve device in which a flow rate control valve is provided in the valve casing. The flow rate control valve is a stepping motor with one axial direction of the valve casing as the forward direction and the other axial direction as the return direction. A valve body connected to an operation rod driven in the forward and reverse directions via a motion conversion mechanism by forward and reverse rotation of the output shaft, and a valve seat provided in the valve casing that faces the reverse direction. The valve body is provided with a main valve body portion that can be seated in the valve seat so as to close the valve hole opened in the valve seat, and a valve body that protrudes from the main valve body portion in the forward movement direction and can be inserted into the valve hole. The present invention relates to a valve having a needle-shaped auxiliary valve body and a bypass passage that constantly communicates between the upstream side and the downstream side of the flow rate control valve.

Conventionally, as this type of gas valve device, a valve seat and a valve hole for a flow control valve are formed in a valve casing, and a valve seat member that is movable in the axial direction and a valve that urges the valve seat member in the recovery direction. A seat urging means, a valve seat stopper means for stopping the movement of the valve seat member in the return direction at a predetermined position, and an electromagnetic safety valve are provided so that the electromagnetic safety valve faces the valve seat member in the forward movement direction. The formed valve seat for the safety valve, the valve body for the safety valve that can be seated on this valve seat, the valve spring that urges this valve body in the recovery direction to sit on the valve seat for the safety valve, and the safety valve. It has a suction piece connected to the valve body via a valve shaft extending in the forward movement direction and an electromagnet facing the suction piece, and the valve seat member is used for a flow control valve by moving the operation rod in the forward movement direction. It is known that the valve body for the safety valve is pushed to the valve opening position where the suction piece abuts on the electromagnet via the valve seat member. (See, for example, Patent Document 1).

In this system, the flow control valve is placed on the valve seat for the flow control valve while the operation rod moves in the forward direction and is in a predetermined stroke range, that is, in a predetermined position where the valve seat member is stopped by the valve seat stopper means. Only the bypass passage when it is in the range between the position where the main valve body part of the valve body is seated and the position immediately before the valve seat for the safety valve comes into contact with the valve body for the safety valve in the valve open position. The gas flows through the gas and is maintained in a state where the gas flow rate is minimized. Therefore, when the gas flow rate is reduced to the minimum amount, when the number of pulses input to the stepping motor reaches the predetermined number required for moving the operation rod to the predetermined minimum flow rate position within the predetermined stroke range. The stepping motor is stopped. However, if the stepping motor slips due to the components of the motion conversion mechanism driven by the stepping motor, the prying of the operating rod, etc., even if the number of pulses input to the stepping motor reaches a predetermined number, the operating rod actually operates. The position of the above does not reach the predetermined stroke range, and the gas flow rate may become larger than the minimum amount.

Here, a gas valve device is provided in the gas supply path for the stove burner to which the pot bottom temperature sensor is attached, and the gas flow rate is minimized when the detection temperature of the pot bottom temperature sensor rises to the upper limit temperature of a predetermined set temperature range. There is one that performs temperature control to increase the gas flow rate when the detection temperature of the pot bottom temperature sensor drops to the lower limit temperature of the set temperature range. In this case, when the detection temperature of the pot bottom temperature sensor rises to the upper limit temperature of the set temperature range and the operation rod is moved and stopped at the minimum flow rate position, the actual stop position of the operation rod is in the predetermined stroke range as described above. If the gas flow rate exceeds the minimum amount without reaching the above, the pot bottom temperature greatly overshoots from the upper limit temperature of the set temperature range and rises excessively.

Japanese Unexamined Patent Publication No. 2013-68356

In view of the above points, the present invention has a predetermined stroke in which the actual position of the operation rod maintains the gas flow rate to the minimum amount when the number of pulses input to the stepping motor reaches a predetermined number corresponding to the minimum flow rate position. The challenge is to provide a gas valve device capable of stopping the gas supply when the range is not reached.

In order to solve the above problems, the present invention is a gas valve device in which a flow rate control valve is provided in the valve casing, in which one axial direction of the valve casing is the forward direction and the other is the reverse direction. The flow rate control valve is provided in the valve casing and the valve body connected to the operation rod driven in the forward and reverse directions via the motion conversion mechanism by the forward and reverse rotation of the output shaft of the stepping motor. The valve body is provided with a valve seat facing the return direction, and the valve body has a main valve body portion that can be seated in the valve seat so as to close the valve hole opened in the valve seat, and a valve body in the forward movement direction from the main valve body portion. It has a needle-shaped auxiliary valve body that protrudes and can be inserted into the valve hole, and a bypass passage that constantly communicates between the upstream side and the downstream side of the flow control valve, and the operation rod moves in the forward movement direction to a predetermined value. The gas flow rate is minimized when the main valve body is seated on the valve seat so that the gas flows only through the bypass passage and is maintained in a state where the gas flow rate is minimized when it is in the stroke range. When narrowing down the amount, the number of pulses input to the stepping motor deviates from the predetermined intermediate position of the predetermined stroke range to the forward movement direction side, and the operation rod moves to the predetermined minimum flow rate position within the stroke range. When the predetermined number required for movement is reached, the stepping motor is stopped, and further, a detector provided on any of the output shaft of the stepping motor, the operation rod, and the constituent members of the motion conversion mechanism is operated. It is equipped with a position sensor that detects when the detector is displaced to a predetermined detection position, which is the position of the detector when the rod moves to the predetermined intermediate position, and when the gas flow rate is reduced to the minimum amount, The gas supply is stopped when the number of pulses input to the stepping motor reaches a predetermined number without the displacement of the detector to the detection position being detected by the position sensor.

Here, if slippage does not occur in the stepping motor, the displacement of the detector to the detection position is detected by the position sensor before the number of pulses input to the stepping motor reaches a predetermined number. In this case, the actual position of the operating rod is within the predetermined stroke range, and the gas flow rate is reduced to the minimum amount. On the other hand, if the stepping motor slips and the actual position of the operating rod when the number of pulses input to the stepping motor reaches a predetermined number does not reach the predetermined stroke range, the detector is detected. The number of pulses input to the stepping motor reaches a predetermined number and the drive is stopped without the displacement to the position being detected by the position sensor. Therefore, according to the present invention, the gas supply is stopped when the actual position of the operating rod when the number of pulses input to the stepping motor reaches a predetermined number and the drive is stopped is not within the predetermined stroke range. It's possible and safe.

Further, according to the present invention, since the detection position is set to the position of the detector when the operation rod is in the intermediate position of the predetermined stroke range, the position sensor is caused by an error in the installation position of the position sensor or the like. Even if the actual detection position of the detector detected by the above is slightly deviated from the predetermined detection position, the position of the operating rod corresponding to the actual detection position falls within the predetermined stroke range. Here, if the position of the operating rod corresponding to the actual detection position is before the predetermined stroke range, the pulse input to the stepping motor after the position sensor detects the displacement of the detector to the detection position. Even when the number reaches a predetermined number, it is possible that the actual position of the operating rod has not reached the predetermined stroke range. On the other hand, according to the present invention, as described above, the displacement of the detector to the detection position is not detected by the position sensor before the operation rod enters the predetermined stroke range. As a result, it is possible to prevent the gas supply from not being stopped even though the actual position of the operating rod when the number of pulses input to the stepping motor reaches a predetermined number does not reach the predetermined stroke range.

Further, the gas valve device of the present invention is a valve seat movable in the axial direction in which the valve seat for the flow control valve and the valve hole are formed in the valve casing like the gas valve device described in Patent Document 1. A member, a valve seat urging means for urging the valve seat member in the recovery direction, a valve seat stopper means for stopping the movement of the valve seat member in the recovery direction at a predetermined position, and an electromagnetic safety valve are provided. The electromagnetic safety valve consists of a valve seat for a safety valve formed on the valve seat member so as to face the forward movement direction, a valve body for a safety valve that can be seated on the valve seat, and the valve body is urged in the recovery direction. It has a valve spring that sits on the valve seat for the safety valve, an suction piece that is connected to the valve body for the safety valve via a valve shaft that extends in the forward direction, and an electromagnet that faces the suction piece. Due to the movement in the moving direction, the valve seat member is pushed by the valve body for the flow control valve and moves in the forward movement direction, and the valve body for the safety valve comes into contact with the electromagnet by the suction piece via the valve seat member. It can be made to be pushed to the position. In this case, in the above-mentioned predetermined stroke range, the main valve body portion of the valve body for the flow rate control valve is seated on the valve seat for the flow rate control valve in a state where the valve seat member is in a predetermined position stopped by the valve seat stopper means. It is the range between the position where the valve is opened and the position immediately before the valve seat for the safety valve comes into contact with the valve body for the safety valve at the valve opening position.

Further, in such a gas valve device with a safety valve, the applicant of the present application first connects the motion conversion mechanism to the output shaft so as to rotate in conjunction with the output shaft of the stepping motor according to Japanese Patent Application No. 2016-1420575. It has a tubular cam body concentric with the operation rod connected via a child, and a pin fixed to the operation rod that engages with a spiral cam groove formed in the cam body, and the cam body rotates in the normal direction. We are proposing a cam mechanism that moves the operating rod in the forward and backward directions by the axial thrust that acts from the cam groove through the pin in reverse rotation. In this method, the cam body is movable in the axial direction, and the cam stopper means for stopping the movement of the cam body in the forward movement direction at a predetermined position and the cam urging means for urging the cam body in the forward movement direction. The cam body is stopped by the cam stopper means by the axial reaction force acting from the pin through the cam groove in the forward rotation of the output shaft of the stepping motor after the valve body for the safety valve reaches the valve opening position. It is designed to move in the recovery direction against the urging force of the cam urging means from the predetermined position.

In such a gas valve device, the detector is formed by a protrusion having a mountain portion that rises in the recovery direction, and the detector is projected on the outer peripheral surface of the cam body, and the position sensor is rotated by the detector in the normal rotation of the cam body. If it is composed of a micro switch having a detection lever that is pushed up in the reverse direction by contacting the inclined side that extends in the forward direction from the apex of the mountain part when it is rotationally displaced to the detection position. , The structure can be simplified and the cost can be reduced.

However, in this case, when the cam body moves in the recovery direction from the predetermined position stopped by the cam stopper means due to the forward rotation of the output shaft of the stepping motor after the valve body for the safety valve reaches the valve opening position. In addition, the detection lever may be pushed beyond the operating limit in the recovery direction, causing the microswitch to fail. Therefore, the mountain portion has a second hypotenuse portion extending in the forward direction at an inclination angle equal to or larger than the inclination angle of the cam groove in the reverse direction from the apex portion of the mountain portion, and is used for a safety valve. It is desirable that the detection lever comes into contact with the second hypotenuse when the cam body rotates in the normal direction due to the further forward rotation of the output shaft after the valve body reaches the valve opening position. According to this, when the cam body rotates normally due to the further forward rotation of the output shaft after the valve body for the safety valve reaches the valve opening position and recovers from the predetermined position, the detection lever moves in the returning direction. It is possible to prevent the vehicle from being pushed beyond the operating limit.

The cut side view of the gas valve device of 1st Embodiment of this invention. The perspective view of the gas valve device of 1st Embodiment. (A) (b) (c) A cut side view of a main part showing the operation of the gas valve device of the first embodiment. The perspective view which shows the component member and the valve seat member of the motion conversion mechanism of the gas valve device of 1st Embodiment. (A) (b) A side view showing the relationship between the detector of the gas valve device of the first embodiment and the microswitch. The graph which shows the relationship between the position of the operation rod and the gas flow rate in the gas valve device of 1st Embodiment. The flow chart which shows the content of the throttle control to the minimum flow rate executed by the gas valve apparatus of 1st Embodiment. The cut side view of the gas valve device of the 2nd Embodiment. The cut side view of the main part of the gas valve device of 3rd Embodiment.

With reference to FIGS. 1 and 2, the gas valve device of the embodiment of the present invention includes a tubular valve casing 1, an electromagnetic safety valve 2 arranged in an axially offset portion in the valve casing 1, and a valve casing 1. A flow control valve 3 arranged in series with the electromagnetic safety valve 2 in a portion closer to the other in the axial direction, an operation rod 4 elongated in the axial direction of the valve casing 1 inserted into the valve casing 1 from the other axial direction, and a valve. The rotational movement of the stepping motor 5 mounted on the outer end of the box 11 attached to the other end in the axial direction of the casing 1 and the output shaft 51 of the stepping motor 5 arranged in the box 11 is the axial movement of the operation rod 4. It is provided with a motion conversion mechanism 6 for converting to. In the following description, one of the valve casings 1 in the axial direction will be referred to as a forward movement direction, and the other in the axial direction will be referred to as a return direction.

The valve casing 1 is provided with a gas inflow port 1a located on the upstream side of the electromagnetic safety valve 2 and a gas outflow port 1b located on the downstream side of the flow rate control valve 3. Then, when the electromagnetic safety valve 2 is opened, gas flows from the gas inflow port 1a to the gas outflow port 1b, and the gas is supplied to the stove burner B. The stove burner B is provided with a pot bottom temperature sensor Ba that comes into contact with the bottom surface of the cooking container.

The electromagnetic safety valve 2 includes a valve seat 21 facing in the forward direction, a valve body 22 facing the valve seat 21, a valve spring 23 for urging the valve body 22 in the reverse direction and seating on the valve seat 21, and a valve. It is provided with a suction piece 24 connected to the body 22 via a valve shaft 22a extending in the forward movement direction, and an electromagnet 25 facing the suction piece 24. Then, the valve body 22 is attracted and held at the valve opening position by energizing the electromagnet 25 in a state where the valve body 22 is pushed against the valve spring 23 to the valve opening position where the suction piece 24 abuts on the electromagnet 25. Will be done. When a misfire is detected by the flame detection element (not shown) attached to the stove burner B, the energization of the electromagnet 25 is stopped and the valve body 22 is seated on the valve seat 21 by the valve spring 23. The electromagnetic safety valve 2 is closed to prevent the outflow of gas.

The valve seat 21 of the electromagnetic safety valve 2 is formed on the forward-moving side end surface of the valve seat member 7 which is provided in the valve casing 1 and is movable in the axial direction with respect to the valve casing 1. Further, the inside of the valve casing 1 is composed of a protrusion formed on the inner surface of the valve casing 1 that stops the movement of the valve seat member 7 in the return 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 urging means 72 including a coil spring that urges the valve seat member 7 in the return direction and elastically holds the valve seat member 7 at the predetermined position are provided. Further, a bellofram 73 is provided to prevent gas from flowing to the outside of the valve seat member 7.

The flow rate control valve 3 includes a valve seat 31 formed on the valve seat member 7 so as to face the return direction, and a valve body 32 fixed to the end of the operation rod 4 in the forward direction. The valve body 32 has a main valve body portion 321 that can be seated in the valve seat 31 so as to close the valve hole 31a opened in the valve seat 31, and a main valve body portion 321 that protrudes in the forward movement direction and is inserted into the valve hole 31a. It has a possible needle-shaped auxiliary valve body portion 322 and a bypass passage 323 that constantly communicates with the upstream side and the downstream side of the flow rate control valve 3.

According to the above configuration, when the output shaft 51 of the stepping motor 5 is rotated in the normal direction from the state shown in FIG. 1, the operation rod 4 moves in the forward movement direction via the motion conversion mechanism 6, and first, the flow rate control valve. The main valve body portion 321 of the valve body 32 for use 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 flows. It is pushed by the valve body 32 for the control 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 (state shown in FIG. 3A). .. In this state, the electromagnet 25 is energized to attract and hold the valve body 22 at the valve opening position, and then the output shaft 51 of the stepping motor 5 is reversed, and the operation rod 4, that is, the flow rate control valve is connected via the motion conversion mechanism 6. The valve body 32 for use is moved in the return direction. At this time, the valve seat member 7 follows the valve body 32 and moves in the recovery direction by the urging force of the valve seat urging means 72 to a predetermined position stopped by the valve seat stopper means 71, and the valve seat for the safety valve. The electromagnetic safety valve 2 is opened apart from the valve body 22 in which 21 is attracted and held at the valve opening position. When the operation rod 4 further moves in the recovery direction with respect to the valve seat member 7 which is restrained at a predetermined position, the main valve body portion 321 of the valve body 32 for the flow rate control valve separates from the valve seat 31 for the flow rate control valve. The auxiliary valve body portion 322 gradually escapes from the valve hole 31a, and the gas flow rate gradually increases. After that, the operation rod 4 moves in the forward movement direction, and the flow rate reaches the valve seat 31 for the flow rate adjusting valve in a predetermined stroke range, that is, in a predetermined position where the valve seat member 7 is stopped by the valve seat stopper means 71. Immediately before the safety valve valve seat 21 comes into contact with the safety valve valve body 22 at the valve opening position and the position where the main valve body portion 321 of the control valve valve body 32 is seated (state in FIG. 3B). When it is in the range between the position (state of FIG. 3C), the gas flows only through the bypass passage 323 and the gas flow rate is maintained in the minimum amount.

By the way, it is difficult to control the stepping motor 5 at the moment when the valve body 22 for the safety valve reaches the valve opening position, that is, at the moment when the suction piece 24 comes into contact with the electromagnet 25. Therefore, when the operation rod 4 is pushed in the forward movement direction via the motion conversion mechanism 6 by the forward rotation of the output shaft 51 of the stepping motor 5 after the valve body 22 reaches the valve opening position, the suction piece 24 and the suction piece 24 An excessive force is applied to the contact portion with the electromagnet 25, and the suction piece 24 may be damaged, resulting in poor suction.

Therefore, in the present embodiment, the motion conversion mechanism 6 is configured as follows. That is, as shown in FIG. 4, the motion conversion mechanism 6 is concentric with the operation rod 4 which is connected to the output shaft 51 via the connector 61 so as to rotate in conjunction with the output shaft 51 of the stepping motor 5. It has a tubular cam body 62 and a pin 64 fixed to the operation rod 4 that engages with the spiral cam groove 63 formed in the cam body 62, and the cam groove is rotated in the forward and reverse directions of the cam body 62. It is composed of a cam mechanism in which the operation rod 4 moves in the forward movement direction and the reverse movement direction by an axial thrust acting from the 63 through the pin 64.

The connector 61 has a non-circular hole 611 that fits into the output shaft 51 having a non-circular cross section, and rotates together with the output shaft 51. Further, the connector 61 is provided with a projecting piece portion 612 that engages with a notch portion 622 formed in a small-diameter tubular portion 621 at the end of the cam body 62 on the return direction side to transmit a rotational force.

A guide cylinder 65 extending in the recovery direction from the valve casing 1 is inserted into the cam body 62. The guide cylinder 65 is formed with an elongated hole 651 that is long in the axial direction, and a pin 64 is slidably engaged with the elongated hole 651 in the axial direction. Further, the cam body 62 is movable in the axial direction, and has a cam stopper means 66 composed of an end plate of the box 11 and a cam body 62 that stop the movement of the cam body 62 in the forward movement direction at a predetermined position. A cam urging means 67 including a coil spring for urging the vehicle in the forward direction is provided. Then, in the normal rotation of the output shaft 51 of the stepping motor 5 after the valve body 22 for the safety valve reaches the valve opening position, the cam body 62 is generated by the axial reaction force acting from the pin 64 through the cam groove 63. Is made to move in the recovery direction against the urging force of the cam urging means 67. According to this, even if the output shaft 51 of the stepping motor 5 is further rotated in the normal direction after the valve body 22 for the safety valve reaches the valve opening position, an excessive force is applied to the contact portion between the suction piece 24 and the electromagnet 25. In addition, it is possible to prevent the suction piece 24 from being damaged and causing poor suction. Before the valve body 22 for the safety valve reaches the valve opening position, the cam body 62 does not move in the recovery 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.

By the way, when the detection temperature of the pot bottom temperature sensor Ba rises to the upper limit temperature of the predetermined set temperature range, the gas flow rate is reduced to the minimum amount, and when the detection temperature of the pot bottom temperature sensor Ba drops to the lower limit temperature of the set temperature range. Temperature control may be performed to increase the gas flow rate. When the gas flow rate is reduced to the minimum amount, the number of pulses input to the stepping motor 5 is within the predetermined stroke range (the range between the position in FIG. 3B and the position in FIG. 3C). When the predetermined number required for the movement of the operation rod 4 to the predetermined minimum flow rate position is reached, the stepping motor 5 is stopped.

FIG. 6 shows a change in the gas flow rate when the stepping motor 5 is rotated in the normal direction and the operation rod 4 is moved in the forward movement direction from the maximum flow rate position where the gas flow rate is maximum. The predetermined stroke range is the range of S in FIG. When the operation rod 4 is moved in the forward direction beyond the stroke range S, the valve seat 21 for the safety valve comes into contact with the valve body 22 for the safety valve at the valve opening position, and the gas supply is stopped. ..

Here, when the stepping motor 5 slips due to the components of the motion conversion mechanism 6 driven by the stepping motor 5 or the prying of the operating rod 4, the number of pulses input to the stepping motor 5 reaches the above-mentioned predetermined number. However, the actual position of the operation rod 4 may not reach the predetermined stroke range S, and the gas flow rate may become larger than the minimum amount. As a result, the pot bottom temperature greatly overshoots from the upper limit temperature of the set temperature range and rises excessively.

Therefore, in the present embodiment, when the gas flow rate is reduced to the minimum amount, the number of pulses input to the stepping motor 5 is shifted to the forward movement direction side from the predetermined intermediate position Smid of the predetermined stroke range S. The stepping motor 5 is stopped when a predetermined number required for the movement of the operation rod 4 to a predetermined minimum flow rate position within the stroke range S is reached. Further, the detector 8 provided on the cam body 62, which is a component of the motion conversion mechanism 6, and the detector 8 when the operation rod 4 moves to the predetermined intermediate position Smid are located at a predetermined detection position. A position sensor 9 that detects when the detector 8 is displaced is provided. Then, when the gas flow rate is reduced to the minimum amount, if the number of pulses input to the stepping motor 5 reaches the predetermined number without the displacement of the detector 8 to the detection position being detected by the position sensor 9, the gas I try to stop the supply.

More specifically, with reference to FIG. 5, the detector 8 is composed of a protrusion having a mountain portion 81 protruding in the recovery direction, which protrudes from the outer peripheral surface of the cam body 62. The mountain portion 81 has a first hypotenuse portion 81b extending in the forward direction from the apex portion 81a in the forward rotation direction. Further, the position sensor 9 is a micro switch having a detection lever 91 that abuts on the first hypotenuse portion 81b and is pushed up in the recovery direction when the detector 8 is rotationally displaced to the detection position by the normal rotation of the cam body 62. It is configured. Then, when the detector 8 is rotationally displaced to the detection position shown in FIG. 5A corresponding to the predetermined intermediate position Smid, the microswitch 9 as a position sensor is turned on. According to this, the structure of the detector and the position sensor can be simplified and the cost can be reduced.

However, if nothing is done, the cam body 62 is stopped by the cam stopper means 66 due to the forward rotation of the output shaft 51 of the stepping motor 5 after the valve body 22 for the safety valve reaches the valve opening position. When moving to, the detection lever 91 may be pushed in the return direction beyond the operating limit, and the microswitch 9 may fail. Therefore, the mountain portion 81 further has a second hypotenuse portion 81c that extends in the forward movement direction at an angle equal to or greater than the inclination angle of the cam groove 63 in the reverse direction from the apex portion 81a. Then, when the cam body 62 rotates normally due to the normal rotation of the output shaft 51 of the stepping motor 5 after the valve body 22 for the safety valve reaches the valve opening position, the detection lever 91 is shown in FIG. 5 (b). As shown, it comes into contact with the second hypotenuse portion 81c. According to this, when the cam body 62 moves in the recovery direction from the predetermined position due to the forward rotation of the output shaft of the stepping motor 5 after the valve body 22 for the safety valve reaches the valve opening position, it is detected. It is possible to prevent the lever 81 from being pushed beyond the operating limit in the return direction.

The control content when the gas flow rate is reduced to the minimum flow rate by temperature control is as shown in FIG. 7. First, the stepping motor 5 is driven in STEP 1 to start moving the operation rod 4 in the forward movement direction. Next, in STEP 2, it is determined whether or not the number of input pulses to the motor 5 from the start of driving the stepping motor 5 has reached a predetermined number required for moving the operation rod 4 to the predetermined minimum flow rate position. Then, when the predetermined number is reached, the stepping motor 5, that is, the operation rod 4 is stopped in STEP3. Next, the process proceeds to STEP4, and it is determined whether or not the microswitch 9 has been turned on by then. When the micro switch 9 is turned on, the process proceeds to STEP 5, the current throttle control is terminated, and the gas supply at the minimum flow rate is continued. On the other hand, if the micro switch 9 has not been turned on by then, the process proceeds to STEP 6, and the electromagnetic safety valve 2 is closed by stopping the energization of the electromagnet 25 to stop the gas supply.

Here, if slipping does not occur in the stepping motor 5, the displacement of the detector 8 to the detection position is detected by the microswitch 9 which is a position sensor before the number of pulses input to the stepping motor 5 reaches a predetermined number. Then, the micro switch 9 is turned on. In this case, the actual position of the operating rod 4 is within the predetermined stroke range S, and the gas flow rate is reduced to the minimum amount. On the other hand, if the stepping motor 5 slips and the actual position of the operation rod 4 when the number of pulses input to the stepping motor 5 reaches a predetermined number does not reach the predetermined stroke range S, The displacement of the detector 8 to the detection position is not detected by the micro switch 9, and the number of pulses input to the stepping motor reaches a predetermined number and the drive is stopped without the micro switch 9 being turned on. Therefore, according to the throttle control of the present embodiment, the actual position of the operation rod 4 when the number of pulses input to the stepping motor 5 reaches a predetermined number and the drive is stopped is within the predetermined stroke range S. It is safe because the gas supply can be stopped when there is no gas supply.

Further, according to the present embodiment, since the detection position at which the micro switch 9 is turned on is set to the position of the detector 8 when the operation rod 4 is in the intermediate position Smid of the predetermined stroke range S, the micro switch is used. Even if the actual detection position of the detector 8 on which the microswitch 9 is turned on deviates slightly from the predetermined detection position due to an error in the installation position of 9, the position of the operation rod 4 corresponding to the actual detection position is the above-mentioned predetermined position. Enter the stroke range S. Here, if the position of the operating rod corresponding to the actual detection position is before the predetermined stroke range S, the number of pulses input to the stepping motor 5 reaches the predetermined number after the micro switch 9 is turned on. Even if this is the case, there is a possibility that the actual position of the operating rod 4 has not reached the predetermined stroke range S. On the other hand, according to the present embodiment, as described above, the micro switch 9 is not turned on before the operating rod 4 enters the predetermined stroke range S. As a result, it is possible to prevent the gas supply from being stopped even though the actual position of the operating rod 4 when the number of pulses input to the stepping motor 5 reaches a predetermined number does not reach the predetermined stroke range S. it can.

Although the detector 8 is provided on the cam body 62 in the first embodiment, 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 configured at the end of the pin 64. Then, when the operating rod 4 is at a predetermined intermediate position (position shown in FIG. 8) in the predetermined stroke range, the detection lever 91 of the micro switch 9 which is a position sensor is brought into contact with the detector 8 and pushed up, and the micro The switch 9 is turned on.

Further, when a magnet as a detector is attached to the end of the pin 64 and the position sensor is composed of a magnetic sensor such as a Hall IC so that the operation rod 4 is at a predetermined intermediate position in the predetermined stroke range. The magnet may face the magnetic sensor in close proximity to switch the sensor output signal. Further, the detector can be provided on a member other than the constituent members of the motion conversion mechanism 6, such as the output shaft 51 of the stepping motor 5 and the operation rod 4. However, when the detector is provided on the output shaft 51 of the stepping motor 5, the position of the detector when the operation rod 4 reaches a predetermined intermediate position is relatively large due to the variation in play in the motion conversion mechanism 6. It fluctuates. In order to keep this variation small, it is desirable to provide a detector on the constituent member of the motion conversion mechanism 6 or the operation rod 4 which is not directly connected to the output shaft 51.

The present invention can also be applied to the gas valve device of the third embodiment shown in FIG. In the third embodiment, the valve seat member 7'which is immovable in the axial direction is provided in the valve casing 1, and the valve seat member 7'is movable in the axial direction with respect to the operation rod 4 at the end of the operation rod 4 on the forward movement direction side. In addition, a valve body 32 for a flow rate control valve that is urged in the forward direction by a spring 32a is attached. In this case, the operation rod 4 is seated at the seating start position (FIG. 9) in which the main valve body portion 321 of the valve body 32 is seated on the valve seat 31 for the flow rate control valve formed on the valve seat member 7'in the direction of the return direction. A predetermined stroke between the position of the upper half of the operation rod) and the push-off position (the position of the lower half of the operation rod in FIG. 9) in which the spring 32a is compressed with respect to the valve body 32 and moved by a predetermined distance in the forward movement direction. When in range, the gas flow rate is minimal. Then, although not shown, a detector and a position sensor similar to those in the above embodiment are provided so that when the operation rod 4 moves to a predetermined intermediate position in the predetermined stroke range, the position sensor can detect this. The aperture control is performed in the same manner as in the above embodiment.

1 ... valve casing, 2 ... electromagnetic safety valve, 21 ... valve seat for safety valve, 22 ... valve body for safety valve, 22a ... valve shaft, 23 ... valve spring, 24 ... suction piece, 25 ... electromagnet, 3 ... flow control valve , 31 ... Valve seat for flow control valve, 31a ... Valve hole, 32 ... Valve body for flow control valve, 321 ... Main valve body, 322 ... Sub valve body, 323 ... Bypass passage, 4 ... Operation rod, 5 ... Stepping motor, 51 ... Output shaft, 6 ... Motion conversion mechanism, 61 ... Connector, 62 ... Cam body, 63 ... Cam groove, 64 ... Pin, 66 ... Cam stopper means, 67 ... Cam urging means, 7 ... Valve Seat member, 71 ... Valve seat stopper means, 72 ... Valve seat urging means, 8 ... Detector, 81 ... Mountain part, 81a ... Top part, 81b ... First oblique side portion, 81c ... Second oblique side portion, 9 ... Micro Switch (position sensor), 91 ... Detection lever.

Claims (3)

A gas valve device in which a flow control valve is provided in the valve casing. The flow control valve is a positive of the output shaft of the stepping motor, with one axial direction of the valve casing as the forward direction and the other axial direction as the return direction. A valve is provided with a valve body connected to an operation rod driven in the forward and reverse directions via a motion conversion mechanism by rolling and reversing, and a valve seat provided in the valve casing that faces the reverse direction. The body has a main valve body that can be seated in the valve seat so as to close the valve hole opened in the valve seat, and a needle-shaped sub that protrudes from the main valve body in the forward movement direction and can be inserted into the valve hole. It has a valve body and a bypass passage that constantly communicates between the upstream side and the downstream side of the flow control valve, and when the operation rod moves in the forward movement direction and is within a predetermined stroke range, the main valve body portion In a valve seat where gas flows only through the bypass passage and is maintained in a state where the gas flow rate is minimized.
When the gas flow rate is reduced to the minimum amount, the number of pulses input to the stepping motor deviates from the predetermined intermediate position of the predetermined stroke range to the predetermined minimum flow rate position in the stroke range. When the predetermined number required for the movement of the operation rod is reached, the stepping motor is stopped.
Further, a predetermined detector provided on any of the output shaft of the stepping motor, the operating rod, and the constituent members of the motion conversion mechanism, and a predetermined position of the detector when the operating rod moves to the predetermined intermediate position. It is equipped with a position sensor that detects when the detector is displaced to the detection position.
When the gas flow rate is reduced to the minimum amount, if the number of pulses input to the stepping motor reaches a predetermined number without the displacement of the detector to the detection position detected by the position sensor, the gas supply should be stopped. Characterized gas valve device. The gas valve device according to claim 1, wherein the valve seat for the flow control valve, the valve seat member movable in the axial direction in which the valve hole is formed, and the valve seat member are reactivated in the valve casing. A valve seat urging means for urging in the direction, a valve seat stopper means for stopping the movement of the valve seat member in the return direction at a predetermined position, and an electromagnetic safety valve are provided, and the electromagnetic safety valve goes to the valve seat member. A valve seat for a safety valve formed so as to face the direction of movement, a valve body for a safety valve that can be seated on this valve seat, and a valve that urges this valve body in the recovery direction to sit on the valve seat for the safety valve. It has a spring, a suction piece connected to the valve body for the safety valve via a valve shaft extending in the forward movement direction, and an electromagnet facing the suction piece, and the valve seat is moved by the movement of the operation rod in the forward movement direction. The member is pushed by the valve body for the flow control valve and moves in the forward movement direction, and the valve body for the safety valve is pushed to the valve opening position where the suction piece abuts on the electromagnet via the valve seat member. The predetermined stroke range is a position where the main valve body portion of the valve body for the flow control valve is seated on the valve seat for the flow control valve while the valve seat member is in a predetermined position stopped by the valve seat stopper means. , A gas valve device characterized in that the range is between the position immediately before the valve seat for the safety valve comes into contact with the valve body for the safety valve existing at the valve opening position. The gas valve device according to claim 2, wherein the motion conversion mechanism is connected to the output shaft via a coupler so as to rotate in conjunction with the output shaft, and has a tubular shape concentric with the operation rod. It has a cam body and a pin fixed to the operation rod that engages with the spiral cam groove formed in the cam body, and by axial thrust acting from the cam groove through the pin in the forward and reverse rotation of the cam body. It is composed of a cam mechanism that allows the operation rod to move in the forward and backward directions, and the cam body is movable in the axial direction and stops the movement of the cam body in the forward direction at a predetermined position. A cam stopper means and a cam urging means for urging the cam body in the forward movement direction are provided, and after the valve body for the safety valve reaches the valve opening position, the output shaft is further rotated forward from the pin to the cam groove. In the case where the cam body is stopped by the cam stopper means due to the axial reaction force acting through the cam body, the cam body moves in the recovery direction against the urging force of the cam urging means.
The detector is composed of a protrusion having a mountain portion that rises in the recovery direction and protrudes from the outer peripheral surface of the cam body, and the mountain portion is in the forward movement direction from the apex portion of the mountain portion in the forward rotation direction. The position sensor has a first hypotenuse portion that extends inclined to, and the position sensor comes into contact with the first hypotenuse portion and is pushed up in the recovery direction when the detector is rotationally displaced to the detection position due to the normal rotation of the cam body. It is composed of a micro switch having a detection lever, and the mountain portion has a second hypotenuse portion extending in the forward direction at an angle equal to or greater than the inclination angle of the cam groove in the reverse direction from the apex portion of the mountain portion. A gas valve device characterized in that the detection lever comes into contact with the second hypotenuse when the cam body rotates normally due to further normal rotation of the output shaft after the valve body for the safety valve reaches the valve opening position.

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