Electromagnet control device

Abstract

The present invention provides an electromagnet control device that absorbs the back electromotive force generated when one of the energized coils is de-energized by the other de-energized coil, thereby suppressing the residual attractive force that pulls the movable core towards the fixed core, and enabling the movable core to return to its original position quickly. [Solution] The electromagnet control device 1 has an operating state in which the movable iron core is attracted to the fixed iron core by the attractive force generated by energizing coils 9B and 9C and moves to the operating position; a holding state in which energization is maintained to one of the coils 9B while the other coil 9C is de-energized to hold the movable iron core in the operating position; and a non-operating state in which both coils are de-energized in the holding state and the attractive force is eliminated. It has a switch means 20 that opens and closes between the two coils, and an operating means 21 that switches the switch means 20 from the open position to the closed position when an induced voltage is generated in the other coil 9C that is de-energized in the holding state.

Description

Technical Field

[0001] The present invention relates to an electromagnetic control device that controls an electromagnet that attracts a movable iron core to a fixed iron core by an attractive force generated by energizing a coil portion, and particularly to an electromagnetic control device suitable for use in a solenoid valve.

Background Art

[0002] This type of electromagnetic control device includes an electromagnet that disposes a movable iron core (plunger) opposite to a fixed iron core and attracts the movable iron core to the fixed iron core by an attractive force generated by energizing a coil portion, and controls this electromagnet. The coil portion has a configuration of a double coil in which the same type of first coil and second coil are combined. By energizing both coils, the movable iron core is attracted to the fixed iron core to operate the movable iron core to an operating position, and while maintaining energization of one coil, the other coil is de-energized to hold the movable iron core at the operating position, thereby reducing power consumption.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in such a conventional electromagnetic control device, when, while holding the movable iron core at the operating position, the energization of one coil that has been maintaining energization is stopped and the movable iron core is to be returned to the original position, a counter electromotive force is generated and an attractive force that attracts the movable iron core to the fixed iron core remains, so there is a problem that the movable iron core cannot be quickly returned.

[0005] The object of the present invention is to provide an electromagnet control device that can quickly return the movable core to its original position by absorbing the back electromotive force generated when one of the energized coils is de-energized with the other de-energized coil, thereby suppressing the residual attractive force that pulls the movable core towards the fixed core. [Means for solving the problem]

[0006] To achieve these objectives, the present invention employs the following means: An electromagnet control device that controls an electromagnet that attracts a movable iron core to a fixed iron core with an attractive force generated by energizing a coil section, wherein the coil section comprises two coils connected in parallel, and has an operating state in which the attractive force generated by energizing both coils attracts the movable iron core to the fixed iron core and moves it to the operating position, a holding state in which energizing one of the coils is maintained while the other coil is de-energized to hold the movable iron core in the operating position, and a non-operating state in which both coils are de-energized to eliminate the attractive force, the two coils are connected via a switch means, the switch means has a closed position in which the two coils are electrically connected and an open position in which the electrical connection between the two coils is interrupted, the switch means is in the closed position in the operating and non-operating states and in the open position in the holding state, and the device is equipped with an operating means that switches the switch means from the open position to the closed position when an induced voltage is generated in the other coil that is de-energized in the holding state.

[0007] In this case, the coil section may consist of two coils spaced apart in the axial direction to form a first coil and a second coil, with a control board placed between the first coil and the second coil, and the control board provided with the switch means and the operating means. [Effects of the Invention]

[0008] As detailed above, the invention described in claim 1 comprises a coil section comprising two coils connected in parallel, having an operating state in which the movable iron core is attracted to the fixed iron core by the attractive force generated by energizing both coils and moves to the operating position, a holding state in which energization is maintained to one of the coils in the operating state while the other coil is de-energized to hold the movable iron core in the operating position, and a non-operating state in which the attractive force is eliminated by de-energizing both coils in the holding state, and the two coils are connected via a switch means, the switch means having a closed position in which the two coils are electrically connected and an open position in which the electrical connection between the two coils is interrupted, and is located in the closed position in the operating and non-operating states and in the open position in the holding state, and an operating means is provided to switch the switch means from the open position to the closed position when an induced voltage is generated in the other coil that is de-energized in the holding state. Therefore, when the mechanism switches from the held state to the non-operating state, the switch mechanism closes, electrically connecting the two coils. This allows the non-operating coil to absorb the back electromotive force generated when one of the energized coils is de-energized, suppressing the residual attractive force that would otherwise pull the movable core towards the fixed core, and enabling the movable core to return to its original position quickly. Furthermore, the mechanism includes an operating means that switches the switch mechanism from the open position to the closed position when an induced voltage is generated in the non-operating coil in the held state. Therefore, if an external force acts on the movable core and attempts to cause abnormal operation, an induced voltage is generated in the other coil, switching the switch mechanism to the closed position. The attractive force generated by energizing both coils then pulls the movable core in, effectively preventing abnormal operation of the movable core.

[0009] Furthermore, in the invention described in claim 2, the coil section consists of two coils spaced apart in the axial direction to form a first coil and a second coil, with a control board placed between the first coil and the second coil, and the control board provided with switch means and operating means. As a result, the switch means and operating means can be integrally arranged in the coil section, making the entire device compact. [Brief explanation of the drawing]

[0010] [Figure 1] This is a longitudinal cross-sectional view showing an electromagnet control device, one embodiment of the present invention, applied to a solenoid valve. [Figure 2] This is an electrical circuit diagram showing a non-operating state in one embodiment. [Figure 3] This is a time chart showing the time evolution of the current flowing through the coil, the open / closed state of the switch mechanism, and the generation of the induced voltage in one embodiment. [Figure 4] This is an electrical circuit diagram showing the operating state of one embodiment. [Figure 5] This is an electrical circuit diagram of one embodiment in a holding state. [Modes for carrying out the invention]

[0011] One embodiment of the present invention will be described below with reference to the drawings. Figure 1 shows an electromagnet control device according to one embodiment of the present invention applied to a solenoid valve. The electromagnet control device 1 is attached to one axial end of the valve body 3 of the solenoid valve 2. In addition, an electromagnet control device 4, which has the same configuration as electromagnet control device 1, is attached to the other axial end of the valve body 3, opposite to the axial end of the valve body 3. A terminal box T is placed on the upper part of the valve body 3.

[0012] A fitting hole 5 is formed in the valve body 3, penetrating it axially. A spool-shaped valve body 6 is housed in the fitting hole 5 so as to be slidable in the axial direction. On the inner circumferential surface of the fitting hole 5, a supply passage P is connected approximately in the axial center, load passages A and B are spaced apart on both sides of the supply passage P in the axial direction, and a discharge passage R is spaced apart axially outward from the load passages A and B. The supply passage P is connected to a fluid pressure source, load passages A and B are connected to actuators (not shown), and the discharge passage R is connected to the low-pressure side. The valve body 6 protrudes in an annular shape, forming two lands 6A and 6B. By moving in the axial direction, the lands 6A and 6B open and close the respective passages P, A, B, and R, switching communication between each passage P, A, B, and R. Springs 7A and 7B are placed at both ends of the valve body 6 in the axial direction, and the force of the springs 7A and 7B holds the valve body 6 in a neutral position that blocks the passages P, A, B, and R.

[0013] A cylindrical fixed core 8 of the electromagnet control device 1 is screwed into the opening of the fitting hole 5, which is opened at one axial end of the valve body 3, and the electromagnet control device 1 is attached and fixed to the axial end of the valve body 3 as described above. An electromagnet control device 4, which has the same configuration as the electromagnet control device 1, is attached and fixed to the opening of the fitting hole 5, which is opened at the other axial end of the valve body 3, as described above. Hereafter, the electromagnet control device 1 will be used as a representative example. It has the same configuration. Therefore, in the following, the electromagnet section will be described using the first electromagnet section 22 as a representative example.

[0014] The electromagnet control device 1 operates by using the attractive force generated by energizing the coil section 9 to attract the movable iron core 10 to the fixed iron core 8, thereby pressing the valve body 6 via the rod member 11. It is constructed by fitting a coil block 13, which has the coil section 9, onto a cylindrical block 12, and the coil block 13 is fixed between the valve body 3 and the coil block 13 by a lock nut 14 that is screwed onto the protruding end of the cylindrical block 12.

[0015] The cylindrical block 12 is made of a magnetic material and has a cylindrical fixed core 8 that screws into the valve body 3. A cylindrical cylindrical member 15 made of a non-magnetic material is welded and fixed to the fixed core 8, and a bottomed, cylindrical yoke member 16 made of a magnetic material is further welded and fixed to the cylindrical member 15. The movable core 10 is made of a magnetic material and has a cylindrical shape. It is fitted axially slidably inside the cylindrical member 15 and the yoke member 16 and is positioned opposite the fixed core 8. The rod member 11 is fitted axially slidably at the radial center of the fixed core 8, and both axial ends abut the valve body 6 and the movable core 10, respectively. As the movable core 10 is attracted to the fixed core 8, the rod member 11 presses against the valve body 6.

[0016] The coil block 13 is formed by housing a cylindrical coil section 9, which has a through-hole 9A formed axially through its radial center, in a roughly cup-shaped cover member 17 made of magnetic material with a closed bottom and a through-hole 17A formed axially through its radial center, and then molding it integrally with molding resin 18. The coil section 9 consists of a first coil 9A and a second coil 9B connected in parallel and spaced apart in the axial direction, with a disc-shaped control board 19 placed between the first coil 9A and the second coil 9B. Both coils 9A and 9B are formed by axially superimposing multiple printed circuit boards, each with a coil pattern printed on its front and back surfaces. The control board 19 is provided with switch means 20 (shown in Figure 2) and operating means 21 (shown in Figure 2), which will be described in detail later.

[0017] 22 is a pair of connecting pins, which are electrically connected to the lead wires of the coil section 9 and integrally molded with molding resin 18, and positioned to protrude toward the terminal box T. The connecting pins 22 are inserted into the cylindrical block 12 through holes 9A and 17A, and the coil block 13 is fitted onto it, thereby inserting into the inside of the terminal box T and electrically connecting the coil section 9 to an external DC power supply 23 (shown in Figure 2). The magnetic circuit that generates an attractive force to attract the movable iron core 10 to the fixed iron core 8 when current is supplied to the coil section 9 is formed by the movable iron core 10, the fixed iron core 8, the yoke member 16, and the cover member 17.

[0018] As shown in Figure 2, the switch means 20 is normally closed and is provided between the first coil 9B and the second coil 9C connected in parallel on the positive side of the DC power supply 23, and between the first coil 9B and the second coil 9C connected in parallel on the negative side of the DC power supply 23. It has a closed position that electrically connects both coils 9B and 9C, and an open position (shown in Figure 5) that disconnects the electrical connection between both coils 9B and 9C. 24 is a first relay that switches the switch means 20, and is connected in parallel with both coils 9B and 9C to the DC power supply 23. When it is not energized, it switches the switch means 20 to the closed position, and when it is energized, it switches the switch means 20 to the open position with a delay. 25 is a power switch, which is installed between the positive side of the DC power supply 23 and both coils 9B and 9C, and between the negative side of the DC power supply 23 and both coils 9B and 9C. It can be switched open and closed, and in the closed position, it energizes both coils 9B and 9C, and in the open position, it deenerges both coils 9B and 9C.

[0019] 26 is a second switch that is always on, and is provided in series with the power switch 25 on the negative side of the DC power supply 23 and connected in parallel to the second coil 9C on the side of the first coil 9B from the power switch 25 and on the side of the second coil 9C from the switch means 20. It has an open position for interrupting the electrical connection and a closed position for making the electrical connection (shown in FIGS. 4 and 5). 27 is a second relay for switching the second switch 26, and is connected in parallel to the first relay 24 with respect to the DC power supply 23. When non-powered to itself, it switches the second switch 26 to the open position, and when powered to itself, it switches the second switch 26 to the closed position.

[0020] The operating means 21 is composed of an n-type electrolytic effect transistor, is arranged in series with the first relay 24, connects the drain D to the first relay 24, connects the source S to the negative side of the DC power supply 23, and connects the gate G to the positive side of the DC power supply 23 on the side of the second coil 9C from the switch means 20 via the IC28 and the capacitor 29. The capacitor 29 converts the induced voltage generated in the non-powered second coil 9C into a pulse signal. The IC28 performs NOT logical operation and outputs a Hi signal normally, and outputs a Lo signal when an induced voltage occurs and it tries to operate due to an external force acting on the movable iron core 10. When an induced voltage occurs in the non-powered second coil 9C, the operating means 21 inputs a Lo signal from the IC28 to the gate G, makes the source S and the drain D non-conductive, makes the first relay 24 non-powered, and switches the switch means 20 from the open position to the closed position due to the non-powering of the first relay 24.

[0021] 30 is a first diode, is connected in parallel to the second coil 2C and in series with the second switch 26, allows the flow of current from the negative side to the positive side of the second coil 9C, and blocks the flow of current from the positive side to the negative side of the second coil 9C. 31 is a second diode, is connected in parallel to the second relay 27, allows the flow of current from the negative side to the positive side of the DC power supply 23, and blocks the flow of current from the positive side to the negative side of the DC power supply 23. The first relay 24, the second switch 26, the second relay 27, the IC28, the capacitor 29, the first diode 30, and the second diode 31 are provided on the control board 19 together with the switch means 20 and the operating means 21.

[0022] The electromagnet control device 1 has three operating states: an operating state (Figure 4) in which the movable core 10 is attracted to the fixed core 8 by the attractive force generated by energizing both coils 9B and 9C and moves to the operating position; a holding state (Figure 5) in which energization is maintained to one of the coils 9B while the other coil 9C is de-energized, holding the movable core 10 in the operating position; and a non-operating state (Figures 1 and 2) in which both coils 9B and 9C are de-energized in the holding state, eliminating the attractive force.

[0023] Figure 3 is a time chart showing the current flowing to the first coil 9B, the current flowing to the second coil 9C, the current flowing to the coil section 9 (the sum of the currents flowing to both coils 9B and 9C), the generation of induced voltage, the open / closed state of the power switch 25, the open / closed state of the switch means 20, the open / closed state of the second switch 26, and the Hi-Lo signal input to the gate G of the operating means 21.

[0024] As shown in the time chart in Figure 3, the power switch 25 is in the open position when not operating and in the closed position when operating and in the held state. The switch mechanism 20 is in the closed position when not operating and in the operating state and in the open position when in the held state. Note that the switch mechanism 20 is in the open position when operating because the first relay 24 switches from the open position to the closed position with a delay of a certain amount of time. The second switch 26 is in the open position when not operating and in the closed position when operating and in the held state, similar to the power switch 25. The first coil 9B is de-energized when not operating and energized and current flows when operating and in the held state. The second coil 9C is de-energized when not operating and in the held state and energized and current flows when operating. The coil section 9 shows no energization when not operating, shows the current flowing to both coils 9B and 9C when operating, and shows the current flowing to the first coil section 9B when in the held state. The induced voltage in the second coil 9C occurs in the unenergized second coil 9C when an external force acts on the movable core 10 and attempts to operate. The signal to the gate G is normally a Hi signal, and when an external force acts on the movable core 10 and attempts to operate, an induced voltage is generated and a Lo signal is input.

[0025] Next, we will explain how this configuration works. Figures 1 and 2 show the non-operating state, with no current supplied to the coil 9 and the movable core 10 stopped at a position axially separated to the right from the fixed core 8. The valve body 6 is in the neutral position, blocking the passages P, A, B, and R. At this time, the power switch 25 is in the open position, the switching means 20 is in the closed position, and the second switch 26 is in the open position.

[0026] In this non-operating state, when the power switch 25 is switched to the closed position, the second relay 27 is energized and the second switch 26 is switched to the closed position, as shown in Figure 4. At this time, the switch mechanism 20 maintains the closed position. Current from the positive side of the DC power supply 23 flows through the first coil 9B and returns to the negative side of the DC power supply 23 from the second switch 26, and also flows through the second coil 9C from the switch mechanism 20 and returns to the negative side of the DC power supply 23 from the second switch 26, energizing both coils 9B and 9C. Then, the attractive force generated by energizing both coils 9B and 9C attracts the movable iron core 10 to the fixed iron core 8, putting it into the operating position. The movable iron core 10 slides to the left in Figure 1 and is attracted to the fixed iron core 8, and the rod member 11 presses the valve body 6 to the left in Figure 1. The valve body 6 slides to the left in Figure 1, switching the load passage A to connect with the supply passage P, and switching the load passage B to connect with the discharge passage R.

[0027] In the operating state shown in Figure 4, after a certain period of time, the first relay 24 switches the switch means 20 to the open position with a delay, as shown in Figure 5. The first coil 9B remains energized, while the second coil 9C becomes de-energized, resulting in a holding state where the movable iron core 10 is held in the operating position. At this time, the back electromotive force generated in the second coil 9C circulates in a loop from the negative side of the second coil 9C through the second switch 26 and the first diode 28 back to the positive side of the second coil 9C and is completely dissipated.

[0028] When the power switch 25 is switched to the open position while the valve is in the holding state shown in Figure 5, it returns to the non-operating state shown in Figure 2, and both the first coil 9B and the second coil 9C become de-energized, the switch mechanism 20 switches to the closed position, and the second switch 26 switches to the open position. The attractive force that draws the movable core 10 to the fixed core 8 is eliminated, and the valve body 6 slides to the right in the diagram due to the force of the spring 7B, returning to the position shown in Figure 1, and blocking the passages P, A, B, and R. The movable core 10 is pressed to the right in Figure 1 by the rod member 11, and moves away from the fixed core 8, returning to the position shown in Figure 1. At this time, the back electromotive force generated in the first coil 9B enters the negative side of the second coil 9C through the switch mechanism 20 from the negative side of the first coil 9B, generating a reverse magnetic flux and canceling out the magnetic force.

[0029] Furthermore, in the holding state shown in Figure 5, if an abnormality occurs where an external force acts on the movable core 10 and attempts to operate, an induced voltage is generated in the other unenergized coil 9C. This induced voltage is converted into a pulse signal by the capacitor 29, and the IC 28 outputs a Lo signal which is input to the gate G of the operating means 21. The operating means 21 de-energizes the first relay 24 by making the connection between the source S and the drain D non-conductive, and switches the switch means 20 from the open position to the closed position. As a result, the second coil 9C is energized in addition to the first coil 9B, and the attractive force generated by the energization of both coils 9B and 9C attracts the movable core 10.

[0030] Next, in the state shown in Figure 1, when the other electromagnet control device 4 is energized, the valve body 6 slides to the right in Figure 1, switching the load passage A to the discharge passage R and switching the load passage B to the supply passage P. Then, when the electromagnet control device 4 is de-energized, the valve body 6 slides to the left in the diagram due to the force of the spring 7A and returns to the diagrammed position, blocking the passages P, A, B, and R.

[0031] In this operation, the coil section 9 is provided with two coils 9B and 9C connected in parallel, and has an operating state in which the movable iron core 10 is attracted to the fixed iron core 8 by the attractive force generated by energizing both coils 9B and 9C and moves it to the operating position, a holding state in which energization is maintained to one of the coils 9B in the operating state and the other coil 9C is de-energized to hold the movable iron core 10 in the operating position, and a non-operating state in which both coils 9B and 9C are de-energized in the holding state and the attractive force is eliminated, and the two coils 9B and 9C are connected via a switch means 20, and the switch means 20 has a closed position in which the two coils 9B and 9C are electrically connected and an open position in which the electrical connection between the two coils is interrupted, and is located in the closed position in the operating and non-operating states and in the open position in the holding state, and has an operating means 21 that switches the switch means 20 from the open position to the closed position when an induced voltage is generated in the other coil 9C which is de-energized in the holding state. Therefore, when the unit changes from a held state to a non-operating state, the switch means 20 closes and electrically connects both coils 9B and 9C. As a result, the back electromotive force generated when one of the energized coils 9B is de-energized can be absorbed by the other unenergized coil 9C, suppressing the residual attractive force that pulls the movable core 10 towards the fixed core 8, and allowing the movable core 10 to return to its original position quickly.

[0032] Furthermore, the system includes an operating means 21 that switches the switch means 20 from the open position to the closed position by inducing a voltage in the other coil 9C, which is not energized when held. Therefore, in the event of an abnormal operation caused by an external force acting on the movable core 10, an induced voltage is generated in the other coil 9C, causing the switch means 20 to switch to the closed position. The attractive force that energizes both coils 9B and 9C then pulls the movable core 10 in place, effectively preventing abnormal operation of the movable core 10.

[0033] Furthermore, the coil section 9 consists of two coils 9B and 9C spaced apart in the axial direction to form the first coil 9B and the second coil 9C. A control board 19 is placed between the first coil 9B and the second coil 9C, and a switch mechanism 20 and an operating mechanism 21 are provided on the control board 19. As a result, the switch mechanism 20 and the operating mechanism 21 can be integrally arranged in the coil section 9, allowing the entire device to be made compact.

[0034] In the embodiment described above, the coil section 9 was formed by axially superimposing multiple printed circuit boards with coil patterns printed on their front and back surfaces to form two coils 9B and 9C. However, two coils may also be formed by winding wire around a coil bobbin. Furthermore, the solenoid valve 2 was equipped with two electromagnet control devices 1 and 4 to actuate the valve body 6. Of course, it is also possible to equip it with only one electromagnet control device 1. [Explanation of Symbols]

[0035] 1, 4: Electromagnet control device 8: Fixed iron core 9: Coil section 9B: First coil 9C: Second coil 10: Movable core 20: Switching method 21:Operation means

Claims

1. An electromagnet control device for controlling an electromagnet that attracts a movable iron core to a fixed iron core using an attractive force generated by energizing a coil section, wherein the coil section comprises two coils connected in parallel, and has an operating state in which the movable iron core is attracted to the fixed iron core and moved to the operating position by the attractive force generated by energizing both coils, a holding state in which energizing one of the coils is maintained while the other coil is de-energized to hold the movable iron core in the operating position, and a non-operating state in which both coils are de-energized to eliminate the attractive force, the two coils are connected via a switch means, the switch means has a closed position in which the two coils are electrically connected and an open position in which the electrical connection between the two coils is interrupted, the switch means is located in the closed position in the operating and non-operating states and in the open position in the holding state, and the device is equipped with an operating means for switching the switch means from the open position to the closed position when an induced voltage is generated in the other coil that is de-energized in the holding state.

2. The electromagnet control device according to claim 1, characterized in that the coil section comprises two coils spaced apart in the axial direction to form a first coil and a second coil, a control board is placed between the first coil and the second coil, and the control board is provided with the switch means and the operating means.

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