JPS6350820Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an electromagnet that moves a plunger forward and backward by energizing a coil.

Among conventional electromagnets, a plunger operates a spool in a valve, and a differential transformer detects the forward and backward positions of the plunger so that the forward and backward movement of the plunger is adapted to the control signal. There was a problem in that the dynamic transformer was expensive, making it uneconomical.

Therefore, the present invention is an attempt to eliminate the above-mentioned problems, and to provide an electromagnet that is more economical by performing the above-mentioned control using an inexpensive potentiometer.

The drawings showing the embodiments of the present application will be described below. In FIGS. 1 to 3, 1 indicates a solenoid. In this solenoid 1, a cylindrical body 2 is composed of a yoke member 3, a pipe 4, and a stop member 5. The yoke member 3 and the stopper member 5 are made of magnetic material, and the pipe 4 is made of non-magnetic material. A male screw 3a is provided on the outer periphery of the tip of the yoke member 3. 6 is a cylindrical coil, 7 is a lead wire, and 8 is a yoke. This yoke 8 is made of magnetic material,
The cylindrical body 2 is fitted into the through hole 8a formed therein. Reference numeral 9 denotes a round rod-shaped plunger disposed in the space 2a in the cylinder 2 so as to be able to move forward and backward in the axial direction.When the coil 6 is energized, the magnitude of the current in the coil at that time is changed as shown in FIG. It is designed to be sucked in the direction of arrow A by a constant suction force depending on the size. A spool push rod 10 is provided integrally with the plunger 9, and is inserted into a communication hole 5a formed in the stop member 5. Reference numeral 11 denotes a spacer fixed to the stop member 5, which is used to prevent the plunger 9 from adhering to the stop member 5 and to limit the stroke L of the plunger 9. next,
Reference numeral 12 indicates a valve connected to the solenoid 1. In this valve 12, 13 is a valve body, which is connected to the stop member 5 in a watertight manner using an O-ring 14. This valve body 13
As shown in Figure 1, there is a sliding hole 1 as an oil passage.
5, oil supply hole 16, oil drain hole 17 and communication hole 18a,
18b is formed. Reference numeral 19 denotes a spool fitted into the sliding hole 15, which is brought into contact with the spool push rod 10 by a valve spring 20 sealed between the spool 19 and the valve body 13, and can move forward and backward with respect to the plunger 9 integrally. are connected like this. The valve spring 20 is shown in a substantially natural length state in FIG.
In this state, when the plunger 9 is moved by a certain stroke in the direction of arrow A and compressed by this stroke, a spring load proportional to this stroke is applied to the spool 19, as shown in FIG. Next, 21 indicates a position detection device connected to the solenoid 1. This position detection device 2
1, 22 is a hollow case made of metal, resin, etc., and is composed of a case body 23 and a lid body 25 that is watertightly connected to one end of this case body 23 using O-rings 24a and 24b. ing. A threaded hole 26 is formed at the other end of the case body 23, and a female thread 26a of this threaded hole 26 is screwed into the male thread 3a of the cylinder body 2, and oil leakage from this threaded portion is prevented by an O-ring 27. It is prevented by twisting. Reference numeral 28 denotes a hollow portion formed within the case body 23, which is composed of a central hole 28a formed on the tip surface and a horizontal hole 28b formed on the peripheral surface. 2
Reference numeral 9 denotes a holder attachment groove formed on the circumferential surface of the case body 23, and is formed in a portion including the entire opening of the horizontal hole 28b. 30 is the holder mounting groove 29
The holder is fitted into the case 22 and attached to the case 22 by mounting screws 31, 31, and has an insertion hole 30a formed therein. Reference numeral 32 designates a potentiometer disposed within the hollow portion 28, which is composed of a potentiometer main body 33, which is exemplified as a fixed portion, and a brush 34, which is exemplified as a movable portion. This potentiometer main body 33 is fitted into a fitting groove 35 formed at the bottom of the holder mounting groove 29 so as to cover the horizontal hole 28b, and is pressed and fixed to the case 22 by the holder 30. ing. Further, the base of the brush 34 is attached to a brush holder, which will be described later, by mounting screws 36, 36, and the tip thereof is pressed against the potentiometer main body 33 by its own elastic force. 37 is a lead wire connected to the potentiometer body 33, and is inserted into the insertion hole 3.
It is inserted into 0a. A connecting rod 38 is attached to the case 22 so as to be slidable in the directions of arrows A and B, and one end of the connecting rod is passed through one wall of the hollow portion 28 and connected to the plunger 9 by brazing or the like. , the other end is passed through the other wall surface of the hollow portion 28 and is placed in an oil chamber 39 formed within the lid body 25 . This oil passage 39 is connected to the cylinder 2 through a communication hole 40 formed in the case 22 and the screw hole 26.
It communicates with the space 2a inside. 41 and 42 are oil leaking from between the connecting rod 38 and the case 22 to the hollow part 28.
An O-ring 43 is provided to prevent oil from leaking into the hollow portion 28, and a drain hole 43 is used to drain oil that has flowed into the hollow portion 28. Reference numerals 44 and 44 denote guide pins arranged in the hollow portion 28 so as to be parallel to the connecting rod 38, and both ends thereof are fixed to the case 22. 45 has its center hole fitted into the connecting rod 38 and the setscrew 4
6 is a positioning dock which is fixed in an adjustable position; 47 is a brush holder whose center hole is fitted to a connecting rod so as to be relatively rotatable; guide grooves 48, 48 are formed on both sides. and these guide grooves 4
8 and 48 are fitted into the guide pins 44 and 44, respectively. 49 is its both ends 49a, 49b
The through hole is a leaf spring loosely fitted to the connecting rod 38,
Both ends 49a and 49b are the positioning dots 45.
and the brush holder 47 are elastically sandwiched so that the brush holder 47 moves integrally with the connecting rod 38 in the forward and backward direction of the connecting rod 38.

Next, FIG. 5 shows a control circuit 50 attached to the coil 6 in the solenoid 1. In this control circuit 50, 51a, 51b, 51
c is a resistor, 52 is an amplifier, and 53 is a power amplifier. 54 is an input terminal for inputting the control signal A.

When using the above structure, the oil supply hole 16 of the valve 12 is connected to a hydraulic pressure source, and the oil drain hole 17 is connected to a tank by piping. Therefore, communication holes 18 are provided at both ends of the sliding hole 15.
Oil flows in through a and 18b, and solenoid 1
Oil flows into the space 2a from the sliding hole 15 through the communication hole 5a, and oil flows into the oil chamber 39 of the position detection device 21 from the space 2a through the communication hole 40. Next, when a control signal A of a predetermined magnitude preset in order to open the valve 12 by a desired amount is applied to the input terminal 54 of the control circuit 50, this control signal A and the potentiometer of the position detection device 21 The deviation from the detection signal RO as a detection value fed back from the coil 32 is amplified by the amplifier 52 and the power amplifier 53, and since the deviation is large at first, a large coil current flows through the coil 6. Therefore, the plunger 9 is attracted in the direction of arrow A with a large attraction force corresponding to the magnitude of the coil current flowing through the coil 6. As a result, the plunger 9, spool push rod 10 and spool 19
is moved in the direction of arrow A while compressing the valve spring 20 with a large force. When the plunger 9 and the like are moved in the direction of arrow A in this way, the spool 19
A spring load due to compression of the valve spring 20 is applied in the direction of arrow B, and this spring load and the above-mentioned suction force are balanced. On the other hand, when the plunger 9 is moved in the direction of arrow A as described above, the connecting rod 3
8 and the brush holder 47 are also moved in the direction of arrow A, and the brush 34 is slid in the direction of arrow A while contacting the potentiometer main body 33. In this case, even if the plunger 9 or the connecting rod 38 rotates around these axes, the brush holder 4
7 is prevented from rotating about the connecting rod 38 by the guide pins 44, 44, so that the plunger 34 is always moved back and forth along a predetermined reciprocating trajectory to ensure that it maintains contact with the potentiometer body 33. Ru. Next, when the brush 34 is moved in the direction of the arrow A as described above, the value of the detection signal B increases in accordance with the movement, thereby decreasing the deviation from the control signal A, and causing the coil 6 to The magnitude of the flowing coil current becomes smaller. Finally, the plunger 9 moves in the direction of arrow A to a point corresponding to the value of the control signal, the spool 19 moves to an accurate position, and the valve 12 opens accurately to a predetermined opening degree. When operating the valve 12 as described above, the other end of the connecting rod 38 is left in the oil chamber 39, and the spool 19, the plunger 9, the spool push rod 10, and the connecting rod 38 are Since the hydraulic pressure and the hydraulic pressure in the direction of arrow B, that is, in the backward direction are perfectly balanced, the valve 12 can be operated accurately to the opening degree according to the magnitude of the control signal A input to the control circuit 50. This allows for highly accurate control. Next, when closing the valve 12, the input of the control signal A to the control circuit 50 is stopped, and the current to the coil 6 is removed. As a result, the suction force applied to the plunger 9 disappears, and the spool 19 and spool push rod 1
0, plunger 9 and connecting rod 38 are valve spring 2
The spool 19 is moved in the direction of arrow B by the spring load of 0 and returned to its original position.
cut off.

As described above, in this invention, when operating the valve, the plunger 9 can be moved by energizing the coil 6 to operate the valve. Since the position of the valve is detected and the current supply to the coil is controlled in accordance with the detected value, the plunger 9 can be moved to a predetermined position and the valve can be operated accurately.

Furthermore, since the position detecting device 21 is constructed using a potentiometer 32, it has the economical advantage of being very inexpensive.

Furthermore, even if the brush 34 is connected to the plunger 9 using the potentiometer 32 as described above, the brush 34 can freely rotate relative to the connecting rod 38 connected to the plunger 9, and the connecting rod Since the plunger 9 is configured to be able to move integrally in the forward and backward directions of the brush 38, even if the plunger 9 rotates during use and the rotation is transmitted to the connecting rod 38, the rotational force is blocked from being transmitted to the brush and the brush is removed. 34
can be moved forward and backward with respect to the main body 33 of the potentiometer along a predetermined reciprocating trajectory, and the main body 33 and the brush 34 can smoothly slide, and the plunger 9 can be moved to a predetermined position as described above with high reliability. There are effects that can be achieved.

[Brief explanation of the drawing]

The drawings show an embodiment of the present application, and FIG. 1 is a longitudinal sectional view, FIG. 2 is a perspective view showing a part of the position detection device, FIG. FIG. 5 is a graph showing the relationship between the suction force and the relationship between the stroke of the plunger and the spring force of the valve spring. FIG. 5 is an electric circuit diagram. 1...Solenoid, 2...Cylinder, 6...Coil, 9...Plunger, 12...Valve, 13...
... Valve body, 19 ... Spool, 21 ... Position detection device, 22 ... Case, 32 ... Potentiometer, 33 ... Potentiometer body, 34 ...
... Brush, 38 ... Connecting rod, 47 ... Brush holder, 50 ... Control circuit.

Claims (1)

[Scope of utility model registration request] The solenoid includes a coil attached to a cylindrical body and a round rod-shaped plunger that is movable forward and backward within the cylinder so as to move forward and backward when the coil is energized. The spool is connected to the plunger so that it can move forward and backward integrally with the plunger, and the solenoid is connected to a position detection device that detects the forward and backward positions of the plunger. The coil in the solenoid has
When the coil is energized to move the plunger forward or backward, the energization to the coil is controlled to move the plunger to a predetermined position in accordance with a detected value of the forward or backward position of the plunger detected by the position detection device. In an electromagnet equipped with a control circuit configured to It consists of a meter and a connecting rod that is attached to the case so as to be movable forward and backward, and one end of which is connected to the plunger.The main body of the potentiometer is attached to the case, while the brush of the potentiometer is connected to the plunger. An electromagnet characterized in that the electromagnet is attached to a brush holder which is attached to a brush holder that is freely rotatable with respect to the connecting rod and movable integrally in the forward and backward directions of the connecting rod so that the electromagnet can advance and retreat along a predetermined reciprocating trajectory.