JPH0376487B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a motor-driven proportional control valve with a closing function for controlling the gas pressure supplied to the burner of a gas combustion appliance.

Conventional structure and its problems Conventionally, the gas passage section of gas combustion equipment that controls gas pressure and electrically proportionally controls the burner combustion amount has a solenoid valve that opens and closes the gas passage according to an electric signal from a controller. , and a proportional control valve that regulates the gas pressure to the burner nozzle.

Here, in order to maintain the airtightness of the valve and increase its reliability, two solenoid valves should be connected in series, or two solenoid valves should be connected in series.
This is handled by using a dual solenoid valve that has two solenoid valves integrally molded. For this reason, the gas passage section composed of the electromagnetic valve and the proportional control valve has the disadvantage of being expensive.

Therefore, it was considered to add a closing function to the proportional control valve, reduce the number of solenoid valves by one, and configure a gas circuit with the solenoid valve and the gas proportional control valve with the closing function.

A conventional example of a proportional valve with a closing function is shown in FIG. In FIG. 1, reference numeral 1 indicates a valve body that forms a gas passage. Gas flows in from an inlet 2, passes through a primary pressure chamber 3, passes between a valve seat 4 and a valve 5, and reaches a secondary pressure chamber 6. It flows out from outlet 7. A diaphragm 8 and a pressure receiving plate 9 are fixed to the upper part of the valve 5, and the lower end of the pressure regulating spring 10 is in contact with the pressure receiving plate 9. A nut 11 which is prevented from rotating is in contact with the upper end of the pressure regulating spring 10, and a screw 14 to which a shaft 13 of a motor 12 is fixed is screwed into the nut 11. Therefore motor 1
The pressure regulating spring 10 is expanded and contracted by the rotation of the spring 2. Shaft 13 of motor 12
A gear 15 is fixed thereto, and a gear 18 meshed with the gear 15 and fixed to the shaft 17 of a potentiometer 16 is provided. A valve closing spring 19 presses the valve 5 against the valve seat. The spring force is set so as to provide sufficient closing force to the valve 5 when the pressure regulating spring 10 is stretched.

In this configuration, the portion below the pressure regulating spring 10 functions as a well-known gas governor. That is, the gas pressure in the secondary pressure chamber 6 is regulated in accordance with the force of the pressure regulating spring 10 acting on the valve 5. When the motor 12 is energized, the screw 14 and nut 11 convert rotational motion into linear motion, increasing or decreasing the force acting on the valve 5 of the pressure regulating spring 10. At this time, the spring force of the closing spring 19 is applying a closing force to the valve 5, so the motor 12 rotates as shown in FIG. 2, which shows the relationship between the rotation angle of the motor and the pressure in the secondary pressure chamber 6. No secondary pressure is generated. When the force of the pressure regulating spring 10 exceeds the force of the closing spring 19, secondary pressure is generated. At the same time, the rotational position of the motor 12 is transmitted to the potentiometer 16 via gears 15 and 18 and detected as an electrical resistance value. That is, the resistance value of the potentiometer 16 can be made to correspond to the gas pressure in the secondary pressure chamber 6. Therefore, the gas pressure can be controlled by forming an automatic control system that rotates the motor 12 so that the resistance value of the potentiometer 16 becomes a value corresponding to the gas pressure corresponding to the target gas pressure.

In this conventional proportional control valve with a closing function, when the pressure regulating spring 10 expands and contracts to generate force, the force of the valve closing spring 19 always acts on the valve 5, so that sufficient valve closing force is not obtained. If this is desired, it is necessary to increase the set load of the pressure regulating spring 10. Therefore, a motor with large driving force was required, and the motor was also expensive. In addition, in order to obtain a large valve closing force with a practical shape, it is necessary to use a spring with a large spring constant, which results in a large spring constant of the pressure regulating spring and poor gas governor characteristics. .

Purpose of the Invention The present invention provides a proportional control valve used in a gas passage with a closing function, thereby realizing the dual functions of a solenoid valve and a proportional control valve for gas combustion equipment with a single actuator, while providing a large closing force. The purpose of the present invention is to provide a proportional valve with a closing function that has high airtight reliability and excellent governor characteristics.

Structure of the Invention In order to achieve this object, the present invention includes a valve body having a liquid inlet, an outlet, and a valve seat, a valve body facing the valve seat, and a center portion of which is fixed to the valve body in the valve closing direction. a diaphragm on which fluid pressure acts, a motor, a mechanism section that converts the rotational motion of the motor into linear motion, and a pressure regulating spring that expands and contracts with the linear motion of the mechanism section and applies a force in the valve opening direction to the valve body. and a valve closing spring that applies force in the direction of closing the valve body.
a position detector that detects the rotational position of the motor;
In the pressure regulating spring operating range, the valve closing spring is released so that the force of the valve closing spring does not act on the valve element.

With this mechanism, the rotary motion of the motor is converted into linear motion in the mechanical section, and the force of the pressure regulating spring is varied, acting to proportionally control the fluid pressure.The valve closing spring release mechanism also closes the valve. During proportional control, the valve closing spring closes the valve element, and during proportional control, the force of the closing spring is released from the valve element.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 3, 20 is a valve body serving as a gas passage, gas flows in from an inlet 21, and a primary pressure chamber 22
It passes between the O-ring 25 attached to the valve seat 23 and the valve body 24, reaches the secondary pressure chamber 26, and exits at the outlet 27.
More leakage. At the top of the valve body 24, a diaphragm 28, an upper pressure receiving plate 29, and a lower pressure receiving plate 30 are connected to a DF shaft 31.
It is fixed by the tomewa 32. Upper pressure plate 2
9 is in contact with the lower end of the pressure regulating spring 33. The diaphragm 28 is fixed to the valve body 20 with a cover 34. The upper end of the pressure regulating spring 33 is in contact with a spring receiver 35 that is movable up and down inside the cover 34 .

The motor 36 is positioned and fixed to a cap 34 fixed to a mounting plate 37. The rotational motion of the motor 36 is converted into linear motion by a cam 38 and a slide pin 39, which are mechanical parts that convert rotational motion into linear motion. A reduction unit 40 and a potentiometer 41 as a position detector for detecting the rotation angle of the motor are coaxially assembled on the motor 36.
The output shaft of the cam 38 is directly connected to the cam 38. Note that a multi-turn potentiometer such as a 5-turn, 10-turn, etc. potentiometer may be used as the potentiometer, if necessary.
The relationship between the rotation angle of the motor 36 and the displacement of the slide pin 39 can be arbitrarily designed depending on the shape of the cam 38.

On the other hand, a valve closing spring 4 that applies a closing force to the valve body 24
Reference numeral 2 designates a tension spring, which is hooked onto a lever 44 that is linked to the rotation of the cam 38 via a locking member 43 that has play greater than the stroke of the valve body 24 on the DF shaft 31, and is actuated as a link mechanism by a grooved piece 45. There is. The rotation angle of the motor 36 is divided into a valve-closing spring operating range and a pressure regulating spring operating range, and in the pressure regulating spring operating range, the spring force of the valve-closing spring 42 acts to prevent valve closing from acting on the valve element 24. It constitutes a spring release mechanism. 46 is a cancel spring that prevents the weight of the slide pin 39 and the spring holder from acting on the pressure regulating spring 33. 47 is a bias spring that supports the valve body.

The operation of the above configuration will be explained. In this configuration, the portion below the pressure regulating spring 33 functions as a well-known gas governor as in the conventional example. That is, the gas pressure in the secondary pressure chamber is regulated in accordance with the force of the pressure regulating spring 33 acting on the valve body 24. When the motor 36 is energized, a cam 38 directly connected to the motor 36 rotates.
At this time, the spring begins to be displaced, and FIG. 5 shows the relationship between the rotation angle of the motor and the spring displacement. That is, the valve body 24 is closed when the rotation angle is zero, and the force of the valve-closing spring 42 is acting on the valve body 24. As the motor 36 rotates, the lever 44 moves to reduce the displacement of the valve-closing spring 42, causing the valve body 24 to close in the valve-closing spring operating range, which is the rotation angle of the motor 36 set by the timing mechanism. The force of the valve spring no longer acts. Then, the pressure regulating spring 33 begins to be displaced in accordance with the displacement of the slide pin 39, and begins to apply force to the valve body 24. This is the pressure regulating spring operating range. The transformation of the secondary pressure at this time is the sixth
As shown in the figure, in the valve-closing spring operating range, the valve body 24 is closed and no secondary pressure is generated. When the pressure regulating spring operating range is reached, secondary pressure is generated by the force of the pressure regulating spring 24, and the cam 38 is shaped This changes the quadratic function curve shown by the solid line to facilitate pressure setting. Further, as shown by the dashed line, it is also possible to set the pressure regulating spring 33 so that the pressure regulating spring operating range starts at the minimum combustion amount of the burner.

The rotation of the motor 36 is detected as the resistance value of the potentiometer 41, and can be made to correspond to the gas pressure in the secondary pressure chamber 26. Therefore, it is possible to form an automatic control system that rotates the motor 36 so that the resistance value of the potentiometer 41 becomes a value corresponding to the target gas pressure, and to proportionally control the gas pressure to the burner of the gas combustion equipment. can. Note that if a pulse motor is used as the motor 36, the potentiometer 41
is not necessary and the same operation can be performed.

As described above, according to this embodiment, a proportional control valve with a closing function having the function of an electromagnetic valve is realized with one actuator, and the gas passage section of the gas combustion equipment is simplified and the cost is reduced. Furthermore, since a tension spring is used as the valve closing spring that adds the closing function, it is possible to extend and contract the pressure regulating spring and the valve closing spring in the same direction, resulting in a simple structure. In addition, since the valve closing spring is not involved when the pressure regulating spring operates, the spring constant of the pressure regulating spring can be reduced, resulting in excellent governor characteristics, and the force of the valve closing spring can be increased independently. This has the effect of increasing the reliability of the closing function.

Effect of the invention According to the present invention, the following effects can be obtained.

(1) Conventionally, in a proportional valve with a closing function, a closing force is applied by a valve-closing spring, and a pressure regulating spring is applied to perform proportional control by applying a spring force that exceeds the force of the valve-closing spring. Whereas the secondary pressure was generated by force, the spring forces of the pressure regulating spring and the valve closing spring act separately on the valve body. Therefore, since the force of the pressure regulating spring has no relation to the valve closing spring, it is possible to increase the closing force of the valve body, which has a great effect on improving the reliability of airtightness.

(2) Since the spring constant of the pressure regulating spring is small, it has a great effect on improving performance such as governor characteristics as a proportional control valve.

[Brief explanation of drawings]

Figure 1 is a configuration diagram of a conventional proportional valve with a closing function, Figure 2 is a characteristic diagram showing the relationship between motor rotation angle and secondary pressure in a conventional example, and Figure 3 is an example of a closing function according to the present invention. Figure 4 is a side view of the proportional valve, Figure 5 is a characteristic diagram showing the motor rotation angle and spring displacement, Figure 6 is the relationship between the motor rotation angle and secondary pressure. FIG. 20... Valve body, 21... Inlet, 22... Outlet, 23... Valve seat, 24... Valve body, 28... Diaphragm, 33... Pressure regulating spring, 36... Motor,
38...Cam of the mechanism section, 39...Slide pin of the mechanism section, 42...Valve closing spring, 44...Lever,
45... Grooved piece (44, 45... Valve closing spring release mechanism).

Claims (1)

[Claims] 1. A valve body having a liquid inlet, an outlet, and a valve seat, a valve body facing the valve seat, and a center portion fixed to the valve body so that fluid pressure acts in the valve closing direction. A diaphragm, a motor, a mechanism section that converts the rotational motion of the motor into linear motion, an adjustment spring that expands and contracts with the linear motion of the mechanism section and applies a force in the valve opening direction to the valve body, and a valve body that is placed in front of the valve body. A closing function consisting of a valve-closing spring that applies a force in the direction of closing the valve, and a valve-closing spring release mechanism that prevents the force of the valve-closing spring from acting on the valve element in the adjustment spring operating range. With proportional valve. 2. The proportional valve with a closing function according to claim 1, which uses a tension spring as the valve closing spring.