JPH0337671B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric valve that controls the flow rate by converting the rotational motion of a motor into a linear motion of the valve shaft, and the valve shaft position is adjusted to a preset valve shaft position before tightening and frictional force is generated on the threaded portion. This relates to a control method that accurately moves the valve stem in a straight line, or in other words, stops the rotation of the motor.

In conventional electric valves, a structure for mechanically stopping the rotation of the motor is built into the valve. An example of this is explained with reference to FIG. 1. , a male thread 4, a rotor 5 of a multi-pole magnetized motor, and a bearing end 6 are integrally formed in this order on the outer peripheral surface of a cylindrical permanent magnet, and the male thread 4 is fixed to the valve body 7 and is centered on the outer peripheral surface of a cylindrical permanent magnet. It is fitted with a propulsion bearing 9 having a screw thread 8, and the bearing end 6 is fitted with a bearing 11 fixed in a case 10 made of a non-magnetic material.

A stator coil 12 of the motor is fixed to the case 10 at a position corresponding to the rotor 5 of the motor, and the axial width of the motor rotor 5 is wider than the axial width of the stator coil 12. The dimensions are larger. The case 10 has a fluid inlet/outlet 13,
14 and the valve body 7 having the valve seat 2 by plasma welding or the like in an airtight manner. Furthermore, stop pins 15 and 16 are fixed on the valve stem 1 by a method such as press fitting at a distance from both ends of the male thread 4, and a stopper 17 in the shape of a round pin that restricts the rotation of the stop pins 15 and 16. was fixed through the propulsion bearing 9.

With the above structure, when a predetermined amount of current is applied to the stator coil 12 of the motor, the rotor 5 rotates, and the valve shaft 1 rotates in the forward valve closing direction due to the screw action of the male thread 4 and the female thread 8. (to the left in the drawing) or rearward in the valve opening direction (to the right in the drawing) to a preset valve shaft position (for example, in the valve closing direction, the valve part 3 is seated on the valve seat 2). In order to avoid the situation where the valve closes and a strong screwing friction force is generated in the threaded parts 4 and 8, making the next valve opening movement impossible, an extremely small gap is provided between the valve part 3 and the valve seat 2. ) with stop pin 15 or 16 and stopper 1
7 comes into contact and the linear movement of the valve stem is stopped.
The stop pin 16 works when the movement in the valve closing direction is stopped, and the stop pin 15 works when stopping the movement in the valve opening direction. Here, the pin-shaped stopper 17 is the second
As shown in the figure, by selectively inserting the screw into one of the fixing holes 19 formed at equal angles on the surface of the propulsion bearing 9, variations in the axial stop position within the screw pitch P can be reduced. It has been adjusted to

In the conventional electric valve configured as described above, the rotational movement of the motor is stopped mechanically, so the valve's stopping function is reliable.
It had the following drawbacks.

(1) Noise is generated when the stopper pins 15 and 16 hit the stopper 17 with an impact.

This is particularly a problem when applying this electric valve to household appliances such as room air conditioners and gas combustion appliances that require strict low noise levels.

(2) A high level of accuracy is required in the processing and assembly of the retaining pins 15, 16 and the stopper 17, resulting in high costs.

The present invention is intended to solve the above-mentioned drawbacks, and in detail, like the conventional products, the rotor 5 of the motor is made of a permanent magnet, and the rotor 5 and the valve stem 1 are integrated. The axial position of the valve shaft 1 is magnetically detected by utilizing the rectilinear movement accompanied by rotation, and the rotation of the motor is stopped when the valve shaft 1 reaches a predetermined position.

Hereinafter, a configuration example of the electric valve of the present invention will be explained in detail with reference to FIG. 3.

The present invention is directed to a case 10 which is made of a non-magnetic material, and which is fixed at a position corresponding to the rotor 5 of the motor on the outer periphery of the case 10. Child 5
A magnetic sensor 20 that detects magnetic force is fixed, and the output of this magnetic sensor 20 is input to a motor drive circuit (not shown), and when the sensor output exceeds a certain level, the rotation of the motor is stopped. This is what I did.

The rotor 5 of the motor in the present invention is exactly the same as the conventional product, and the rotor 5 is multi-pole magnetized on the outer circumferential surface of a cylindrical permanent magnet, and its width l in the axial direction is fixed to the motor. It is configured to be longer than the axial width dimension W of the child coil 12.

Therefore, when the valve shaft 1, which is integrally formed with the motor rotor 5 and has the male thread 4, is in the fully closed or fully open position with respect to the valve seat 2, the motor rotor 5 is connected to the motor stator coil 12. From △=l−
It is configured so that only W is protruded.

Since the present invention is configured as described above, the valve shaft 1
When the motor has not reached the fully closed or fully open position, the magnetic force of the motor rotor 5 does not act on the magnetic sensor 20, and the motor changes the amount of current to the stator coil 12 (the number of pulses in the case of a stepping motor, the inductor type AC synchronous In the case of a motor, it rotates in proportion to the number of cycles).

When the valve stem 1 approaches the fully closed or fully open position, one end surface of the motor rotor 5 gradually comes out of the motor stator coil 12 and approaches the magnetic sensor 20, and the magnetic sensor 20 detects the rotation of the motor. The magnetic force of the child 5 is now detected. When the detected amount reaches an amount previously associated with the fully closed and fully open positions of the valve stem 1, a signal to stop the motor is issued from the motor drive circuit, and the motor rotation stops → the linear movement of the valve stem 1 stops.

The magnetic sensor 20 according to the present invention is shown in FIGS.
The one shown in FIG. 6 can be considered as an example. This magnetic sensor is made of a soft magnetic plate material, and its shape is such that the magnetic poles 21 are equally divided into half the number of poles of the motor rotor 5 on the same circumference as the outer diameter of the case 10. A magnetic circuit is formed by integrally configuring one end of each magnetic pole 21 with an annular yoke 22, an electric conductor 23 is wound around the outer circumference of the magnetic pole 21, and both ends of this electric conductor 23 are opened. This is what I did.

FIG. 5 shows an example in which the above-mentioned magnetic sensor 20 of the present invention is attached to a motor-operated valve, and shows the state when the valve stem 1 has almost reached the fully closed position. Like the stator coil 12, it is inserted and fixed onto the case 10.

To explain the detection state of magnetic force using FIG. 6, in FIG. 6, the magnetic pole 21 corresponds to the N pole of the rotor 5 of the motor, so the magnetic pole 21 and the yoke 22 are magnetized to become the S pole, and the magnetic circuit is formed. From this state, when the motor rotor 5 rotates to the right or left, the magnetic poles 21 correspond to the opposite magnetic forces of the permanent magnets, such as the opposite S pole, then the N, S, etc. Therefore, an induced voltage (current) is generated in the electric conductor 23.

The induced voltage (current) at this time differs greatly depending on whether or not the motor rotor 5 is located under the magnetic pole 21 of the magnetic sensor 20. Therefore, the axial position of the motor rotor 5, that is, the valve shaft 1 It is possible to distinguish between fully closed and fully open.

As described above, in the present invention, the outer circumferential surface of a cylindrical permanent magnet is multi-pole magnetized, and the axial width l is larger than the axial width W of the stator coil 12 of the motor. The valve shaft 1 integrated with the rotor 5 is detected by detecting the magnetic force of the rotor 5 of the elongated motor with a magnetic sensor 20 having a simple configuration.
Because of the configuration that determines the axial position of the
This is an extremely useful invention in practice, as it eliminates the need for mechanical impact noise, which had been a problem, and completely eliminates it.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional side view showing an example of the configuration of a conventional electric valve, FIG. 2 is a perspective view of a conventional propulsion bearing, and FIG. 3 is a longitudinal sectional side view showing an example of the configuration of an electric valve according to the present invention. FIG. 4 is a perspective view showing the magnetic pole configuration of the magnetic sensor of the present invention, FIG. 5 is a partial longitudinal sectional side view of an electric valve equipped with the magnetic sensor of the present invention, and FIG. 6 is a cross section along the line shown in FIG. figure. 1...Valve stem, 2...Valve seat, 3...Valve part, 4...Male thread,
5... Motor rotor, 6... Bearing end, 7... Valve body,
8...Female thread, 9...Propulsion bearing, 10...Case, 11
...Bearing, 12...Motor stator coil, 13,1
4... Fluid inlet/outlet, 15, 16... Stopping pin, 17
...stopper, 19...fixing hole, 20...magnetic sensor,
21...Magnetic pole, 22...Yoke, 23...Electric conductor.

Claims (1)

[Claims] 1. By energizing the stator coil 12 of the motor fixed to the outer periphery of the case 10 made of a non-magnetic material,
Valve shaft 1 with male thread 4 housed in case 10
The degree of opening of the valve seat 2 is controlled by rotating the rotor 5 of a motor integrally formed with the valve and converting this rotation into linear movement of the valve shaft 1 by means of a propulsion bearing 9 having a female thread 8. In the electric valve, a stator coil 12 is provided on the outer periphery of a case 10 made of a non-magnetic material at a position corresponding to the rotor 5 of the motor, which is formed by multipole magnetization on the outer periphery of a cylindrical permanent magnet. Axial width dimension l of motor rotor 5
is formed to be larger than the axial width W of the stator coil 12, and the magnetic force of the rotor 5 of the motor is detected on the case at the front and rear of the end of the stator coil 12 of the motor, or either one of them. Valve position detection of an electric valve, characterized in that a magnetic sensor 20 is fixed, and the motor rotation is stopped when the output of the magnetic sensor 20 exceeds a predetermined amount.
How to stop. 2. By energizing the stator coil 12 of the motor fixed to the outer periphery of the case 10 made of non-magnetic material,
Valve shaft 1 with male thread 4 housed in case 10
The degree of opening of the valve seat 2 is controlled by rotating the rotor 5 of a motor integrally formed with the valve and converting this rotation into linear movement of the valve shaft 1 by means of a propulsion bearing 9 having a female thread 8. In the electric valve, a stator coil 12 is provided on the outer periphery of a case 10 made of a non-magnetic material at a position corresponding to the rotor 5 of the motor, which is formed by multipole magnetization on the outer periphery of a cylindrical permanent magnet. Axial width dimension l of motor rotor 5
is formed to be larger than the axial width W of the stator coil 12, and a magnetic pole 21 made of a soft magnetic material is provided on the case at the front and rear of the stator coil 12 end of the motor, or either one of them. case 10
1/2 of the number of poles of the rotor 5 of the motor are equally spaced on the same circumference as the outer diameter of the motor, and one end of each magnetic pole 21 is magnetically integrated by an annular yoke 22. and wind the electric conductor 23 on the outer circumference of the magnetic pole 21, and open both ends of the electric conductor 23.
A magnetic sensor 20 that outputs the induced voltage (current) appearing at both ends of this magnetic sensor 20 is fixed, and this magnetic sensor 2
A method for detecting and stopping a valve position of an electric valve, characterized in that a motor rotation is stopped when a zero output exceeds a predetermined amount.