Electromagnetic valve opening degree control device

Abstract

The utility model discloses an electromagnetic valve opening degree control device which comprises a PWM regulator used for regulating output voltage and further comprises a first resistor, an MOS switch tube and a fly-wheel diode, one end of the first resistor is connected with the output end of the PWM regulator, the other end of the first resistor is grounded, the grid electrode of the MOS switch tube is connected with the output end of the PWM regulator, the source electrode of the MOS switch tube is grounded, and the other end of the first resistor is grounded. The drain electrode of the MOS switch tube is connected with one end of a coil of the electromagnetic valve, the other end of the coil of the electromagnetic valve is connected with the first power source, the drain electrode of the MOS switch tube is further connected with the anode end of the fly-wheel diode, and the cathode end of the fly-wheel diode is connected with the first power source. The utility model has the advantages of simple structure and low cost.

Description

Technical Field

[0001] The invention relates to the electromagnetic field, and in particular to a solenoid valve opening control device. Background Art

[0002] Real-time flow control is required in many aspects of industry and civil use, especially in chemical process control, where strict flow control is required at all times. For flow control in process control, solenoid valves are mostly used to control the valve opening, and the valve opening is controlled by current. The principle is to use the coil of the solenoid valve to generate a magnetic field in the iron core, and the strength of the magnetic field of the iron core controls the opening of the valve body. In other words, the higher the voltage or current loaded on the solenoid valve, the larger the opening of the solenoid valve, and the smaller the voltage or current loaded on the solenoid valve, the smaller the opening of the solenoid valve.

[0003] The solenoid valve opening control device currently in use includes a two-position three-way solenoid valve, a three-position five-way solenoid valve and a pneumatic valve connected in sequence, the pneumatic valve includes an outer cylinder, an inner cylinder and an opening detection module, the two output air paths of the two-position three-way solenoid valve are respectively provided with a first pressure regulating valve and a second pressure regulating valve, the output air paths are combined and connected to the three-position five-way solenoid valve, one of the output air paths of the three-position five-way solenoid valve is connected to the outer cylinder, and the other output air path is connected to the inner cylinder, the two-position three-way solenoid valve, the three-position five-way solenoid valve and the opening detection module are all connected to a control module, the control module realizes control of the two-position three-way solenoid valve and the three-position five-way solenoid valve through PWM pulse control, thereby realizing control of the valve opening size.

[0004] The above-mentioned electromagnetic valve opening control device uses parts such as an outer cylinder, an inner cylinder and an opening detection module, and its structure is relatively complex and the cost is also relatively high. Utility Model Content

[0005] The utility model provides a solenoid valve opening control device with simple structure and low cost.

[0006] The electromagnetic valve opening control device includes a PWM regulator for adjusting the output voltage, and also includes a first resistor, a MOS switch tube, and a freewheeling diode. One end of the first resistor is connected to the output end of the PWM regulator, and the other end of the first resistor is grounded. The gate of the MOS switch tube is connected to the output end of the PWM regulator, the source of the MOS switch tube is grounded, the drain of the MOS switch tube is connected to one end of the coil of the electromagnetic valve, and the other end of the coil of the electromagnetic valve is connected to the first power supply. The drain of the MOS switch tube is also connected to the anode end of the freewheeling diode, and the cathode end of the freewheeling diode is connected to the first power supply.

[0007] Further, the PWM regulator includes a second power supply, a first adjustable resistor, a second adjustable resistor, a first diode, a first capacitor, a second capacitor, and a 555 timed multivibrator, the second power supply is connected to one end of the first adjustable resistor, the other end of the first adjustable resistor is connected to one end of the second adjustable resistor, the other end of the second adjustable resistor is connected to one end of the first capacitor, and the other end of the first capacitor is grounded;

[0008] An anode terminal of the first diode is connected to the other end of the first adjustable resistor, and a cathode terminal of the first diode is connected to one end of the first capacitor;

[0009] The VC1 pin and the RST pin of the 555 timing multivibrator are respectively connected to the second power supply, the DST pin of the 555 timing multivibrator is connected to the other end of the first adjustable resistor, the THR pin and the TRI pin of the 555 timing multivibrator are respectively connected to the other end of the second adjustable resistor, the CON pin of the 555 timing multivibrator is connected to one end of the second capacitor, the other end of the second capacitor is grounded, and the OUT pin of the 555 timing multivibrator is connected to one end of the first resistor and the gate of the MOS switch tube.

[0010] Furthermore, the PWM regulator further includes a fourth resistor, one end of the fourth resistor is connected to the OUT pin of the 555 timing multivibrator, and the other end of the fourth resistor is grounded.

[0011] Furthermore, a third capacitor for noise reduction is included, and the third capacitor is connected in parallel at both ends of the coil of the solenoid valve.

[0012] Furthermore, the PWM regulator is a single chip microcomputer or a PLC.

[0013] The PWM signal generated by the output end of the PWM regulator is added to the gate end of the MOS switch tube to control the on and off of the MOS switch tube. Since the voltage output by the PWM regulator can be adjusted, the PWM regulator can output different voltages. After the MOS switch tube is turned on, the voltage at both ends of the coil is: the difference between the voltage of the first power supply and the voltage of the output end of the MOS switch tube. The value of the first power supply is fixed. The voltage at the output end of the MOS switch tube is adjusted by the PWM regulator as needed. Therefore, the voltage at both ends of the coil can be adjusted as needed. According to the principle that the higher the voltage loaded on the coil, the larger the opening of the solenoid valve, and the smaller the voltage loaded on the solenoid valve, the smaller the opening of the solenoid valve, it can be known that the utility model can adjust the opening of the solenoid valve, thereby controlling the flow and pressure of the hydraulic medium flowing through the solenoid valve. According to the structure of the utility model, the utility model does not use parts such as an outer cylinder, an inner cylinder and an opening detection module to control the opening of the solenoid valve. Therefore, not only is the structure simple, but also the cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a simplified diagram of the solenoid valve opening control device.

[0015] Figure 2 This is the circuit schematic diagram of the solenoid valve opening control device. DETAILED DESCRIPTION

[0016] First embodiment

[0017] like Figure 1 to Figure 2 As shown, the electromagnetic valve opening control device of this embodiment includes a PWM regulator for adjusting the output voltage, a first resistor R1, a MOS switch tube Q1, and a freewheeling diode D2. One end of the first resistor R1 is connected to the output end of the PWM regulator, the other end of the first resistor R1 is grounded, the gate of the MOS switch tube Q1 is connected to the output end of the PWM regulator, the source of the MOS switch tube Q1 is grounded, the drain of the MOS switch tube Q1 is connected to one end of the coil L1 of the electromagnetic valve Y1, the other end of the coil L1 of the electromagnetic valve Y1 is connected to the first power supply VDD, the drain of the MOS switch tube Q1 is also connected to the anode end of the freewheeling diode D2, the cathode end of the freewheeling diode D2 is connected to the first power supply VDD, and the voltage value of the first power supply VDD is 24V. A fuse is connected between the first power supply VDD and the coil L1.

[0018] The PWM signal generated at the output end of the PWM regulator is added to the gate end of the MOS switch tube Q1 to control the on and off of the MOS switch tube Q1. Since the voltage output by the PWM regulator can be adjusted, the PWM regulator can output different voltages. After the MOS switch tube Q1 is turned on, the voltage across the coil L1 is: the difference between the first power supply VDD and the voltage at the output end of the MOS switch tube Q1. According to the principle that the higher the voltage loaded on the coil L1, the larger the opening of the solenoid valve, and the smaller the voltage loaded on the solenoid valve, the smaller the opening of the solenoid valve, it can be seen that the utility model can adjust the opening of the solenoid valve, thereby controlling the flow and pressure of the hydraulic medium flowing through the solenoid valve. According to the structure of the utility model, the utility model does not use parts such as an outer cylinder, an inner cylinder and an opening detection module to control the opening of the solenoid valve. Therefore, not only is the structure simple, but also the cost is reduced.

[0019] In addition, the freewheeling diode D2 can prevent the sudden voltage generated at both ends of the inductor L1 when the current flowing through the coil L1 changes. Therefore, the freewheeling diode D2 can make the current change more smoothly and avoid the occurrence of sudden current, so that the current flowing through both ends of the coil L1 is in a stable state. Normally, the output end of the solenoid valve Y1 is connected to the solenoid reversing valve Y2, and the output end of the solenoid reversing valve Y2 is usually connected to the hydraulic cylinder T1. Therefore, the opening of the solenoid valve Y1 is in a stable state, which can promote the flow and pressure of the hydraulic medium to be in a stable state, thereby stabilizing the working state of the hydraulic cylinder T1.

[0020] In this embodiment, the PWM regulator includes a second power supply VCC, a first adjustable resistor R2, a second adjustable resistor R3, a first diode D1, a first capacitor C1, a second capacitor C2, and a 555 timed multivibrator U1. The voltage value of the second power supply VCC is 5V. The second power supply VCC is connected to one end of the first adjustable resistor R2, the other end of the first adjustable resistor R2 is connected to one end of the second adjustable resistor R3, the other end of the second adjustable resistor R3 is connected to one end of the first capacitor C1, and the other end of the first capacitor C1 is grounded. The anode end of the first diode D1 is connected to the other end of the first adjustable resistor R2, and the cathode end of the first diode D1 is connected to one end of the first capacitor C1.

[0021] The VC1 pin and the RST pin of the 555 timing multivibrator U1 are respectively connected to the second power supply VCC, the DST pin of the 555 timing multivibrator U1 is connected to the other end of the first adjustable resistor R2, the THR pin and the TRI pin of the 555 timing multivibrator U1 are respectively connected to the other end of the second adjustable resistor R3, the CON pin of the 555 timing multivibrator U1 is connected to one end of the second capacitor C2, the other end of the second capacitor C2 is grounded, the OUT pin of the 555 timing multivibrator U1 is connected to one end of the first resistor R1 and the gate of the MOS switch tube Q1, and the first resistor R1 is a pull-down resistor.

[0022] The first capacitor C1 charging time τ1:

[0023] τ1=R2·C1 ln 2≈0.7R2·C1

[0024] The first capacitor C1 discharge time τ2:

[0025] τ2=R3·C1 ln 2≈0.7R3·C1

[0026] The period T of 555 timing multivibrator U1 is:

[0027] T=τ1+τ2≈0.7C1(R2+R3)

[0028] Duty cycle q:

[0029]

[0030] In the above formula, C1 is the capacitance value of the first capacitor C1, R2 is the resistance value of the first adjustable resistor R2, and R3 is the resistance value of the second adjustable resistor R3.

[0031] It can be known from the period formula and duty cycle formula of the 555 timing multivibrator U1 that the continuous rectangular pulse signal generated by the OUT pin (output end) of the 555 timing multivibrator U1 can adjust the period T by adjusting the first capacitor C1 or the first adjustable resistor R2 and the second adjustable resistor R3, and the duty cycle is adjusted by adjusting the first adjustable resistor R2 and the second adjustable resistor R3. Therefore, the output end of the 555 timer multivibrator generates a pulse width modulated (PWM) pulse signal, and the output voltage can be adjusted by adjusting the period T and duty cycle q of the 555 timing multivibrator U1.

[0032] The PWM regulator further includes a fourth resistor R4, one end of which is connected to the OUT pin of the 555 timing multivibrator U1, and the other end of which is grounded. The fourth resistor R4 is a pull-down resistor.

[0033] This embodiment also includes a third capacitor C3 for noise reduction, and the third capacitor C3 is connected in parallel to both ends of the coil L1 of the solenoid valve Y1. The third capacitor C3 plays a role in noise reduction. The third capacitor C3 can effectively filter out high-frequency noise in the circuit and improve the signal-to-noise ratio and stability of the circuit.

[0034] This embodiment further includes a fifth resistor R5 and an indicator light LED1, which are connected in series and then in parallel at both ends of the coil L1. When the MOS switch tube Q1 is turned on, the indicator light LED1 lights up. Therefore, the indicator light LED1 serves as a power-on indication.

[0035] Second embodiment

[0036] The present invention is not limited to the above embodiments. For example, Figure 2 The PWM regulator can also use a single-chip microcomputer U2 or a PLC. The single-chip microcomputer U2 or the PLC can adjust the output voltage, which belongs to the existing technology and will not be described in detail.

[0037] The PWM regulator in the first embodiment and the PWM regulator in the second embodiment can be combined in one circuit. In this case, a selection switch S2 is connected to the gate end of the MOS switch tube Q1. When the selection switch S2 is connected to the output end of the 555 timing multivibrator U1, the on-off of the MOS switch tube Q1 is controlled by the 555 timing multivibrator U1. When the selection switch S2 is connected to the output end of the single-chip microcomputer U2, the on-off of the MOS switch tube Q1 is controlled by the single-chip microcomputer U2.

Claims

1. A solenoid valve opening control device, comprising a PWM regulator for adjusting an output voltage, characterized in that: The invention also comprises a first resistor (R1), a MOS switch tube (Q1), and a freewheeling diode (D2); one end of the first resistor (R1) is connected to the output end of the PWM regulator, the other end of the first resistor (R1) is grounded, the gate of the MOS switch tube (Q1) is connected to the output end of the PWM regulator, the source of the MOS switch tube (Q1) is grounded, the drain of the MOS switch tube (Q1) is connected to one end of the coil (L1) of the electromagnetic valve (Y1), the other end of the coil (L1) of the electromagnetic valve (Y1) is connected to the first power supply (VDD), the drain of the MOS switch tube (Q1) is also connected to the anode end of the freewheeling diode (D2), and the cathode end of the freewheeling diode (D2) is connected to the first power supply (VDD).

2. The solenoid valve opening control device according to claim 1, characterized in that: The PWM regulator comprises a second power supply (VCC), a first adjustable resistor (R2), a second adjustable resistor (R3), a first diode (D1), a first capacitor (C1), a second capacitor (C2), and a 555 timing multivibrator (U1), wherein the second power supply (VCC) is connected to one end of the first adjustable resistor (R2), the other end of the first adjustable resistor (R2) is connected to one end of the second adjustable resistor (R3), the other end of the second adjustable resistor (R3) is connected to one end of the first capacitor (C1), and the other end of the first capacitor (C1) is grounded; An anode terminal of the first diode (D1) is connected to the other end of the first adjustable resistor (R2), and a cathode terminal of the first diode (D1) is connected to one end of the first capacitor (C1); The VC1 pin and the RST pin of the 555 timing multivibrator (U1) are respectively connected to the second power supply (VCC), the DST pin of the 555 timing multivibrator (U1) is connected to the other end of the first adjustable resistor (R2), the THR pin and the TRI pin of the 555 timing multivibrator (U1) are respectively connected to the other end of the second adjustable resistor (R3), the CON pin of the 555 timing multivibrator (U1) is connected to one end of the second capacitor (C2), the other end of the second capacitor (C2) is grounded, and the OUT pin of the 555 timing multivibrator (U1) is connected to one end of the first resistor (R1) and the gate of the MOS switch tube (Q1).

3. The solenoid valve opening control device according to claim 1, characterized in that: The PWM regulator also includes a fourth resistor (R4), one end of the fourth resistor (R4) is connected to the OUT pin of the 555 timing multivibrator (U1), and the other end of the fourth resistor (R4) is grounded.

4. The solenoid valve opening control device according to any one of claims 1 to 3, characterized in that: The invention also comprises a third capacitor (C3) for reducing noise. The third capacitor (C3) is connected in parallel to both ends of the coil (L1) of the electromagnetic valve (Y1).

5. The solenoid valve opening control device according to claim 1, characterized in that: The PWM regulator is a single chip microcomputer or a PLC.

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