JPH0112035Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a device for preventing chattering of an electric valve in an electric drive machine. When an electric valve is fully closed or fully open, a valve that stops (torque stop) due to the operation of a torque switch tends to have a tendency for the worm to return after the torque switch is turned off and turn the torque switch back on naturally for the following reasons, that is, a chattering phenomenon. occurs. The first reason is that the lead angle of the worm is large and there is no self-locking property, and the second reason is that a slight displacement between the stem and the pusher is magnified in the worm axis direction and the worm axis returns.

Taking these points into consideration, this invention provides a control relay in the electric drive device to prevent chatter (motor This completely prevents repeated on/off cycles.

The device of this invention will be explained below with reference to the drawings.
FIG. 1A is a simplified connection diagram of the rotating parts of the motor 1, and FIG. 1B is a schematic side sectional view of the electric valve device. The stem 3 is opened and closed via a gear 7, a worm 4 connected to the gear 7 via a shaft 7a, and a worm gear 2. This mechanism is a conventional electric valve structure and a detailed explanation will be omitted, but the problem is that when the valve is fully closed or fully open, the spring 5 is compressed and the worm 4 is moved to turn off the torque switch. However, due to the reaction force of the spring 5, the worm 4 returns to its original state and the torque switch is turned on, causing the motor power to repeatedly turn on and off. Figure 2 is an electrical circuit wiring diagram for the case shown in Figure 1.The operating push button PBS and torque switch TSC are connected in series to the relay wire ring MC for opening and closing the electric valve power supply, and this torque switch TSC repeatedly turns on and off. In other words, it turns on and off the relay wire MC for switching on and off the power supply. FIG. 3 is a circuit diagram of a chattering prevention device according to this invention, and portions corresponding to those in FIG. 2 are designated by the same reference numerals. First, PBS has a push button for operation.
MC is the relay wire for opening/closing the electric valve power supply, and ra1 is the relay wire MC for opening/closing the electric valve power supply and the operation push button.
The first contact point a and TSC are connected in series to the PBS and whose operation is controlled by the control relay ring R, and the first contact point _a and TSC are connected in series to the control relay ring R, and the electric valve is fully open or close to fully closed. Limit switch and torque switch that open with RA2 is the limit switch that opens with
_a , and the control relay wire R
a second contact whose actuation is controlled by;
SH is a space heater connected in parallel to the series circuit consisting of the control relay wire R, limit switch _a , and torque switch TSC.

Next, to explain the circuit operation of the device according to this invention, if the push button PBS is turned on and the control relay R is also energized and contacts ra ₁ and ra ₂ are closed, the torque switch TSC is also closed, so the electric The valve power supply opening/closing relay ring MC is energized, and the electric valve advances to the fully open or fully closed state. When the electric valve approaches the fully open or fully closed state, the limit switch _a opens first, but the second contact ra ₂ parallel to it is closed, and the coil R continues to be energized, keeping the contact ra ₁ closed. When the wire ring MC continues to be energized and the electric valve advances further and becomes fully open or fully closed, the torque switch TSC is opened one by one, so the wire ring R is de-energized and the contact ra ₁ is opened. Therefore, even if the torque switch TSC is subsequently closed again, the contact ra ₂ is also open and the coil R is not energized and the electric valve does not chatter. As described above, this invention can completely eliminate the chattering of the electric valve.

Note that the above description states that the limit switch contact opens when fully open or close to fully closed, but if you consider that fully open or close to fully closed is a range of approximately 0.5 to 2.0 mm between the limit switch operating point and the fully closed and fully open points, respectively. good.

Also, Figure 4 shows the operating time diagram of limit switch _a , contact points ra ₁ and ra ₂ by wire ring R, and torque switch TSC. Limit switch _a is turned off 0.5 to 2 mm before fully closing, and torque switch TSC is fully closed. The contact points RA ₁ and RA 2 turn OFF when torque is loaded at the point, and the contacts RA 1 and RA ₂ turn OFF instantly after the torque switch TSC is turned OFF. Furthermore, by using the space heater SH, there is no need for external wiring, which can be done by wiring within the drive device.

[Brief explanation of the drawing]

Figure 1A is a simplified connection diagram of the rotating parts of the motor, Figure 1B is a schematic side sectional view of the electric valve device, Figure 2 is an electric circuit connection diagram for the case of Figure 1, and Figure 3 is based on this invention. The circuit connection diagram of such a chattering prevention device, Fig. 4 shows the contact points between the limit switch _a and the wire ring R.
It is an operation time diagram of ra ₁ , ra ₂ and torque switch TSC. In the figure, 1 is the motor, MC is the relay wire for opening and closing the electric valve power supply, R is the control relay wire, ra ₁ and ra ₂ are the first and second contacts of the relay wire R, and TSC is the torque switch.

Claims (1)

[Scope of utility model registration request] A first contact that works with the control relay wire is provided in series with the electric valve power supply opening/closing relay wire, while the control relay wire and a limit switch contact that opens when the valve is fully open or close to fully closed are connected to the torque switch contact. A device for preventing chattering of an electric valve in an electric drive machine, comprising a second contact connected in series and working in the control relay ring in parallel with the limit switch contact.