Magnetic drill control circuit

Abstract

The present invention discloses a magnetic drilling rig control circuit, comprising a circuit for controlling a main motor B1 and a feed motor B2. The automatic feed magnetic drilling rig control circuit includes a power supply circuit module, a magnetic base power supply circuit module, a magnetic switch self-locking circuit module, a main motor overcurrent protection circuit module, a feed motor control circuit module, a travel switch control circuit module, a feed motor overcurrent protection circuit module, and a main motor drilling and retraction circuit module. The power supply circuit module supplies power to the automatic feed magnetic drilling rig control circuit. The magnetic drilling rig control circuit provided by the present invention can achieve automatic feed drilling and automatic retraction of the magnetic drilling rig.

Description

Technical Field

[0001] The invention relates to a magnetic base drilling rig control circuit. Background Art

[0002] Magnetic drills are also known as magnetic drills or magnetic drills. They are also marketed as magnet drills, steel plate drills, magnet drills, suction drills, and steel plate hole drills. When powered, magnetic drills generate thousands of kilograms of magnetic force through electromagnetic effects, allowing them to adhere to steel plates and structural components, securing the machine in place. The stronger the magnetic force, the more stable the drill body during operation and the higher the drilling accuracy.

[0003] With the development of magnetic drilling rigs, the types of drilling rigs are also increasing. At present, most domestic magnetic drilling rigs require manual operation of the feed handle when drilling, which greatly increases the labor intensity of the user. In particular, the larger the tool specifications, the greater the torque required for feeding, and the greater the labor intensity of the user. Summary of the Invention

[0004] The present invention provides a magnetic base drilling rig control circuit to solve the above-mentioned technical problems, specifically adopting the following technical solutions:

[0005] An automatic feeding magnetic base drilling rig control circuit is used to control the main motor B1 and the feed motor B2. The automatic feeding magnetic base drilling rig control circuit comprises: a power supply circuit module, a magnetic base power supply circuit module, a magnetic switch self-locking circuit module, a main motor overcurrent protection circuit module, a feed motor control circuit module, a travel switch control circuit module, a feed motor overcurrent protection circuit module, and a main motor drilling and retraction circuit module;

[0006] The power circuit module supplies power to the automatic feed magnetic drilling rig control circuit;

[0007] The power supply circuit module includes: rectifier bridge D4, thermistor NTC1, safety capacitor C7, resistor R3, diode D3, capacitor C6, resistor R4, power supply chip U1, transformer P1, capacitor C10, electrolytic capacitor C9, electrolytic capacitor C3, optocoupler U3, resistor R1, Zener diode D8, capacitor C8, diode D2, diode D5, diode D1, electrolytic capacitor C1, inductor L1, electrolytic capacitor C5, electrolytic capacitor C2, capacitor C4, resistor R2, light-emitting diode D6 and three-terminal voltage regulator VR1;

[0008] The power supply is 220V AC. The 220V phase line L is connected to the input terminal 1 of the rectifier bridge D4. The 220V neutral line N is connected to the input terminal 2 of the rectifier bridge D4 through the thermistor NTC1. The input terminal of the rectifier bridge D4 is connected in parallel with the safety capacitor C7. The output terminal 3 of the rectifier bridge D4 is connected to the cathode of the diode D3 through the resistor R3. The anode of the diode D3 is connected to the capacitor C6 and one pole of the resistor R4. The other poles of the capacitor C6 and the resistor R4 are connected and connected to the 5-8 pins of the power chip U1 and the 1 pin of the transformer P1. The 1 pin and 2 pins of the power chip U1 are connected and connected to the capacitor C10, the negative pole of the electrolytic capacitor C9 and the output terminal 4 of the rectifier bridge D4. The output end of the rectifier bridge D4 is connected in parallel with the electrolytic capacitor C3, and the other end of the capacitor C10 is connected to pin 3 of the power supply chip U1 and pin 3 of the optocoupler U3. Pin 4 of the power supply chip U1 is connected to pin 4 of the optocoupler U3 and the positive pole of the electrolytic capacitor C9. Pin 1 and pin 2 of the optocoupler U3 are respectively connected to one end of the resistor R1 and the negative pole of the Zener diode D8. The positive pole of the Zener diode D8 is connected to the power ground. Pin 4 of the output end of the rectifier bridge D4 is connected to capacitor C8 to ground. Pin 3 of the transformer P1 is connected to the positive poles of diodes D2 and D5. Pin 4 of the transformer P1 is connected to the positive pole of the electrolytic capacitor C1 through the diode D1. The negative pole of the electrolytic capacitor C1 is grounded, and pin 5 of the transformer P1 is grounded. The other end of resistor R1 is connected to 12V, the negative poles of diodes D2 and D5 are connected to one end of inductor L1 and the positive pole of electrolytic capacitor C5, the negative pole of electrolytic capacitor C5 is grounded, the other end of inductor L1 is connected to 12V, electrolytic capacitor C2 and capacitor C4 are connected between 12V and ground, 12V is connected to the positive pole of light-emitting diode D6 through resistor R2, the negative pole of light-emitting diode D6 is grounded, the input end of the three-terminal voltage regulator VR1 is connected to 12V, the output end is connected to 5V, and the ground end is grounded.

[0009] Furthermore, the magnetic base power supply circuit module includes: magnetic base P3, diode D9, diode D10, diode D13, rectifier bridge D12, diode D11 and diode D9;

[0010] The positive pole of the magnetic base P3 is connected to the negative pole of the diode D9, the positive pole of the diode D9 is connected to the negative pole of the diode D10, the positive pole of the diode D10 is connected to the negative pole of the diode D13, the negative pole of the diode D13 is connected to the input end of the rectifier bridge D12 and the 220V neutral line N, the negative pole of the magnetic base P3 is connected to the negative pole of the rectifier bridge D12 and the positive pole of the diode D11, and the negative pole of the diode D11 is connected to the negative pole of the diode D9.

[0011] Furthermore, the magnetic switch self-locking circuit module includes: an optocoupler U4, a resistor R6, a magnetic switch P4, a bidirectional thyristor T1, a resistor R12, an optocoupler U5, a capacitor C11 and a resistor R11;

[0012] Pin 1 of the optocoupler U4 is connected to the positive electrode of the diode D10, pin 2 of the optocoupler U4 is connected to the negative electrode of the diode D9 via the resistor R6, pin 6 of the optocoupler U4 is connected to the KA electrode of the magnetic switch P4 and the T2 electrode of the bidirectional thyristor T1, pin 4 of the optocoupler U4 is connected to the 6 pin of the optocoupler U5 via the resistor R12, pin 4 of the optocoupler U5 is connected to the control electrode of the thyristor T1 and one electrode of the capacitor C11, the other electrode of the capacitor C11 is connected to the T1 electrode of the thyristor T1 and to the positive electrode of the diode D13, pin 1 and pin 2 of the optocoupler U5 are connected to 12V and ground respectively via the resistor R11, the output end of the magnetic switch P4 is connected in parallel with the main motor B1, and the input end is connected to the 220V power supply.

[0013] Furthermore, the main motor overcurrent protection circuit module includes: a mutual inductor L2, a diode D20, a resistor R41, a comparator U13, an electrolytic capacitor C18, a resistor R42, a resistor R42, a resistor R35, a resistor R36, a comparator U13, a resistor R27 and a diode D16;

[0014] One end of the mutual inductor L2 is grounded, and the other end is connected to the positive electrode of the diode D20. The negative electrode of the diode D20 is connected to the 5th pin of the comparator U13 via the resistor R41. The positive electrode of the electrolytic capacitor C18 is connected to the positive electrode of the diode D20 and one end of the resistor R42. The negative electrode of the electrolytic capacitor C18 is connected to the other end of the resistor R42 and grounded. 5V is connected to the resistor R36 via the resistor R35. The other end of the resistor R36 is grounded. The 6th pin of the comparator U13 is connected to the midpoint of the resistors R35 and R36. The 7th pin of the comparator U13 is connected to the positive electrode of the diode D16 via the resistor R27. The 4th pin and the 8th pin of the comparator U13 are grounded and 12V respectively.

[0015] Furthermore, the feed motor control circuit module includes: a control chip U2, a switch S2, a switch S1, a relay K1, a transistor Q1, a diode D7, a resistor R5, a resistor R8, a resistor R7, an amplifier U6, a resistor R9 and a resistor R19;

[0016] Pins 1-4 of the control chip U2 are connected to ground, one end of the switch S2, one end of the switch S1 and 5V respectively. Pins 6 and 8 of the control chip U2 are connected to the feed motor B2. Pin 5 of the control chip U2 is connected to the common end of the relay K1. The normally open and normally closed ends of the relay K1 are connected to 24V and 12V respectively. The positive and negative poles of the coil of the relay K1 are connected to 12V and the collector of the transistor Q1 respectively. The positive and negative poles of the coil of the relay K1 are connected to the diode D7. The emitter and base of the transistor Q1 are grounded and connected to pin 2 of the control chip U2 through resistor R5 respectively. Pin 7 of the control chip U2 is connected to resistors R8 and one end of R7. The other end of resistor R7 is grounded. The other end of resistor R8 is connected to pin 5 of the amplifier U6. Pin 6 of the amplifier U6 is grounded through resistor R9. Pins 2-4 and 8 of the amplifier U6 are grounded and 12V respectively. Pins 6 and 7 of the amplifier U6 are connected in parallel with resistor R19.

[0017] Furthermore, the travel switch control circuit module includes: diode D14, resistor R13, optocoupler U7, optocoupler U8, optocoupler U9, optocoupler U8, thyristor Q5, resistor R17, resistor R19, capacitor C12, resistor R14, resistor R18, transistor Q2, resistor R20, optocoupler U10, transistor Q4, resistor R16, resistor R15, resistor R32, resistor R23, travel switch P5, travel switch P2, diode D15, resistor R28, electrolytic capacitor C13, transistor Q3, optocoupler U5, thyristor Q3, optocoupler U12, resistor R29, thyristor Q3, capacitor C14, resistor R30, capacitor C15, resistor R31, optocoupler U11, optocoupler U12, resistor R34 and resistor R33;

[0018] The L1 terminal of the magnetic switch P4 is connected to the cathode of the diode D14, the anode of the diode D14 is connected to the 2nd pin of the optocoupler U7 through the resistor R13, the 2nd pin of the optocoupler U8 is connected to the 1st pin of the optocoupler U7, the 2nd pin of the optocoupler U9 is connected to the 1st pin of the optocoupler U8, the 1st pin of the optocoupler U9 is connected to the N1 terminal of the magnetic switch P4, the 3rd and 4th pins of the optocoupler U9 are connected to the positive electrode of the thyristor Q5 and 12V respectively, the 3rd and 4th pins of the optocoupler U8 are connected to the ground and one end of the resistors R17 and R19 respectively, the other end of the resistor R19 is connected to 12V, the capacitor C12 is connected in parallel with the resistor R19, the 3rd pin of the optocoupler U7 Pin 1 and 2 are connected to ground and one end of resistors R14 and R18 respectively. The other end of resistor R18 is connected to 12V. The other end of resistor R14 is connected to the base of transistor Q2. The emitter and collector of transistor Q2 are grounded and connected to pin 2 of optocoupler U10 through resistor R20 respectively. Pin 1 of optocoupler U10 is connected to 12V. The collector of transistor Q4 is connected to ground through resistors R16 and R15. One end of switch S1 is connected to the midpoint of resistors R15 and R16. The other end of switch S1 is connected to pin 3 of optocoupler U10, one end of switch S2 is connected to one end of resistor R32, and the optocoupler U10 is connected to the 12V supply voltage. Pin 4 is connected to 12V via resistor R23, pin 2 of limit switches P5 and P2 is connected to 12V, the normally closed end of limit switch P5 is connected to the positive electrode of diode D15, the negative electrode of diode D15 is connected to ground via resistor R28, the positive and negative electrodes of electrolytic capacitor C13 are connected to the negative electrode of diode D15 and the base of transistor Q3 respectively, the collector and emitter of transistor Q6 are connected to pin 1 of optocoupler U5 and ground respectively, the normally open end of limit switch P5 is connected to the positive electrode of thyristor Q3 and pin 4 of optocoupler U12, the normally closed end of limit switch P2 is connected to The base of the thyristor Q3 is connected to one end of the capacitor C14, the other end of the capacitor C14 is grounded, the cathode of the thyristor Q3 is grounded via the resistor R30, the capacitor C15 is connected in parallel with the resistor R30, the cathode of the thyristor Q3 is connected to pin 1 of the optocoupler U11 via the resistor R31, the pins 2-4 of the optocoupler U11 are respectively connected to pin 1 of the optocoupler U12, the ground and the pin 3 of the motor control chip, the other end of the switch S2 is connected to pin 2 of the motor control chip U2, the other end of the switch S2 is grounded via the resistors R34 and R33, and the midpoint of the resistors R34 and R33 is connected to pin 3 of the optocoupler U12.

[0019] Furthermore, the feed motor overcurrent protection circuit module includes: a diode D19, an operational amplifier U6, a resistor R22, a comparator U15, a resistor R46, a resistor R47, a resistor R48 and a diode D21;

[0020] The anode of diode D19 is connected to pin 7 of operational amplifier U6, the cathode of diode D19 is connected to pin 5 of comparator U15 via resistor R22, pin 6 of comparator U15 is connected to resistors R46 and R47, the other end of resistor R46 is grounded, the other end of resistor R47 is connected to 5V, pin 7 of comparator U15 is connected to the anode of diode D21 via resistor R48, and the cathode of diode D21 is connected to the positive electrode of electrolytic capacitor C13.

[0021] Furthermore, the main motor drilling and retraction circuit module includes: resistor R43, capacitor C19, resistor R45, resistor R44, resistor R49, comparator U14, diode D18, diode D19, resistor R21, resistor R24, resistor R25, resistor R26, thyristor Q5, resistor R40, resistor R39, diode D17, comparator U14, resistor R38 and resistor R37;

[0022] Pin 3 of comparator U15 is connected to the cathode of diode D20 via resistor R43 and to ground via capacitor C19. Pin 2 of comparator U15 is connected to ground via resistor R45. Pins 4 and 8 of comparator U15 are connected to ground and 12V respectively. Pins 1 and 2 of comparator U15 are connected in parallel with resistor R44. Pin 1 of comparator U15 is connected to pin 2 of comparator U14 via resistor R49. The anode of diode D18 is connected to the anode of diode D19. The cathode of diode D18 is connected to pin 3 of comparator U13 via resistor R21. Pin 2 of comparator U13 is connected to 5V and to ground via resistor R25 respectively via resistor R24. Pin 1 of the comparator U13 is connected to the control electrode of the thyristor Q5 via resistor R26, the positive electrode of the thyristor Q5 is connected to pin 3 of the optocoupler U9, and the negative electrode of the thyristor Q5 is grounded via resistor R40. Pin 1 of the comparator U14 is connected to the positive electrode of the diode D17 via resistor R39, and the negative electrode of the diode D17 is connected to the normally closed end of the travel switch P2. Pin 2 of the comparator U14 is connected to the positive electrode of the electrolytic capacitor C16, and the negative electrode of the electrolytic capacitor C16 is grounded. Pin 3 of the comparator U14 is respectively grounded via resistor R38 and connected to 5V via resistor R37. Pins 4-6 of the comparator U14 are grounded, and pin 8 of the comparator U14 is connected to the negative electrode of the thyristor Q5.

[0023] The present invention is beneficial in that the provided magnetic drill control circuit can realize automatic feeding, drilling and automatic retraction of the magnetic drill. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0025] Figure 1 It is a schematic diagram of a portion of a control circuit of a magnetic base drilling rig of the present invention;

[0026] Figure 2 It is a schematic diagram of another part of the control circuit of a magnetic base drilling rig of the present invention. DETAILED DESCRIPTION

[0027] The following describes in detail embodiments of the present application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0028] like Figure 1 and Figure 2 The figure shows a control circuit for an automatic feed magnetic drill rig according to the present application, which is used to control the main motor B1 and feed motor B2. Feed motor B2 is a DC planetary reduction motor. Specifically, it controls the DC planetary reduction motor to drive the feed shaft up and down. The automatic feed magnetic drill rig control circuit includes a power supply circuit module, a magnetic base power supply circuit module, a magnetic switch self-locking circuit module, a main motor overcurrent protection circuit module, a feed motor control circuit module, a travel switch control circuit module, a feed motor overcurrent protection circuit module, and a main motor drill-through and retraction circuit module. The power supply circuit module provides power to the automatic feed magnetic drill rig control circuit.

[0029] In an embodiment of the present application, the power circuit module includes: a rectifier bridge D4, a thermistor NTC1, a safety capacitor C7, a resistor R3, a diode D3, a capacitor C6, a resistor R4, a power supply chip U1, a transformer P1, a capacitor C10, an electrolytic capacitor C9, an electrolytic capacitor C3, an optocoupler U3, a resistor R1, a Zener diode D8, a capacitor C8, a diode D2, a diode D5, a diode D1, an electrolytic capacitor C1, an inductor L1, an electrolytic capacitor C5, an electrolytic capacitor C2, a capacitor C4, a resistor R2, a light-emitting diode D6 and a three-terminal Zener diode VR1.

[0030] Specifically, the power supply is 220V AC, the 220V phase line L is connected to the input terminal 1 of the rectifier bridge D4, the 220V neutral line N is connected to the input terminal 2 of the rectifier bridge D4 through the thermistor NTC1, the input terminal of the rectifier bridge D4 is connected in parallel with the safety capacitor C7, the output terminal 3 of the rectifier bridge D4 is connected to the cathode of the diode D3 through the resistor R3, the anode of the diode D3 is connected to the capacitor C6 and one pole of the resistor R4, the other pole of the capacitor C6 and the resistor R4 are connected and connected to the 5-8 pins of the power chip U1 and the 1 pin of the transformer P1, the 1 pin and the 2 pin of the power chip U1 are connected and connected to the capacitor C10, the negative pole of the electrolytic capacitor C9 and the 4 pin of the output terminal of the rectifier bridge D4 Connect, the output end of the rectifier bridge D4 is connected in parallel with the electrolytic capacitor C3, the other end of the capacitor C10 is connected to the 3rd pin of the power supply chip U1 and the 3rd pin of the optocoupler U3, the 4th pin of the power supply chip U1 is connected to the 4th pin of the optocoupler U3 and the positive pole of the electrolytic capacitor C9, the 1st and 2nd pins of the optocoupler U3 are respectively connected to one end of the resistor R1 and the negative pole of the Zener diode D8, the positive pole of the Zener diode D8 is connected to the power ground, the 4th pin of the output end of the rectifier bridge D4 is connected to the ground and the capacitor C8, the 3rd pin of the transformer P1 is connected to the positive pole of the diodes D2 and D5, the 4th pin of the transformer P1 is connected to the positive pole of the electrolytic capacitor C1 through the diode D1, the negative pole of the electrolytic capacitor C1 is grounded, and the 5th pin of the transformer P1 is grounded. The other end of resistor R1 is connected to 12V, the negative poles of diodes D2 and D5 are connected to one end of inductor L1 and the positive pole of electrolytic capacitor C5, the negative pole of electrolytic capacitor C5 is grounded, the other end of inductor L1 is connected to 12V, electrolytic capacitor C2 and capacitor C4 are connected between 12V and ground, 12V is connected to the positive pole of light-emitting diode D6 through resistor R2, the negative pole of light-emitting diode D6 is grounded, the input end of the three-terminal voltage regulator VR1 is connected to 12V, the output end is connected to 5V, and the ground end is grounded.

[0031] In an embodiment of the present application, the magnetic base power supply circuit module includes: a magnetic base P3, a diode D9, a diode D10, a diode D13, a rectifier bridge D12, a diode D11 and a diode D9.

[0032] Among them, the positive pole of the magnetic base P3 is connected to the negative pole of the diode D9, the positive pole of the diode D9 is connected to the negative pole of the diode D10, the positive pole of the diode D10 is connected to the negative pole of the diode D13, the negative pole of the diode D13 is connected to the input end of the rectifier bridge D12 and the 220V neutral line N, the negative pole of the magnetic base P3 is connected to the negative pole of the rectifier bridge D12 and the positive pole of the diode D11, and the negative pole of the diode D11 is connected to the negative pole of the diode D9.

[0033] After the mains 220V voltage is rectified by the rectifier bridge D12 after power is turned on, the output pulse voltage is used to power the magnetic base coil, so that the magnetic base P3 can be adsorbed on magnetic metals such as iron plates.

[0034] In an embodiment of the present application, the magnetic switch self-locking circuit module includes: an optocoupler U4, a resistor R6, a magnetic switch P4, a bidirectional thyristor T1, a resistor R12, an optocoupler U5, a capacitor C11 and a resistor R11.

[0035] Specifically, pin 1 of the optocoupler U4 is connected to the positive electrode of the diode D10, pin 2 of the optocoupler U4 is connected to the negative electrode of the diode D9 via the resistor R6, pin 6 of the optocoupler U4 is connected to the KA electrode of the magnetic switch P4 and the T2 electrode of the bidirectional thyristor T1, pin 4 of the optocoupler U4 is connected to the 6 pin of the optocoupler U5 via the resistor R12, pin 4 of the optocoupler U5 is connected to the control electrode of the thyristor T1 and one electrode of the capacitor C11, the other electrode of the capacitor C11 is connected to the T1 electrode of the thyristor T1 and to the positive electrode of the diode D13, pin 1 and pin 2 of the optocoupler U5 are connected to 12V and ground respectively via the resistor R11, the output end of the magnetic switch P4 is connected in parallel with the main motor B1, and the input end is connected to the 220V power supply.

[0036] It's understandable that when the on button of magnetic switch P4 is pressed, KA and N1 connect to the neutral line, and L1 connects to the phase line. Since magnetic base P3 is energized at this time, a voltage difference exists between diodes D9 and D10 in the magnetic base P3 circuit, triggering optocoupler U4. Simultaneously, optocoupler U5 is also triggered, so the control electrode of bidirectional thyristor T1 is connected to KA, the neutral line, via the output ports of U4 and U5. T1 is conductive, so KA remains connected to the neutral line even after the on button of magnetic switch P4 is released. This keeps magnetic switch P4 in the on state, and main motor B1 continues to run. When the off button of magnetic switch P4 is pressed, the internal energized coil is forcibly disconnected, causing main motor B1 to stop.

[0037] In an embodiment of the present application, the main motor overcurrent protection circuit module includes: a mutual inductor L2, a diode D20, a resistor R41, a comparator U13, an electrolytic capacitor C18, a resistor R42, a resistor R42, a resistor R35, a resistor R36, a comparator U13, a resistor R27 and a diode D16.

[0038] Specifically, one end of the mutual inductor L2 is grounded, and the other end is connected to the positive electrode of the diode D20. The negative electrode of the diode D20 is connected to the 5th pin of the comparator U13 through the resistor R41. The positive electrode of the electrolytic capacitor C18 is connected to the positive electrode of the diode D20 and one end of the resistor R42. The negative electrode of the electrolytic capacitor C18 is connected to the other end of the resistor R42 and grounded. 5V is connected to the resistor R36 through the resistor R35, and the other end of the resistor R36 is grounded. The 6th pin of the comparator U13 is connected to the midpoint of the resistors R35 and R36. The 7th pin of the comparator U13 is connected to the positive electrode of the diode D16 through the resistor R27. The 4th pin and the 8th pin of the comparator U13 are grounded and 12V respectively.

[0039] The transformer L2 senses the current of the main motor B1, generating an induced current that passes through R42 and forms a voltage that is input to the positive terminal of the comparator U13. When the induced voltage exceeds the set value, the comparator U13 outputs a high voltage, driving the motor circuit to shut down and operate.

[0040] In an embodiment of the present application, the feed motor control circuit module includes: a control chip U2, a switch S2, a switch S1, a relay K1, a transistor Q1, a diode D7, a resistor R5, a resistor R8, a resistor R7, an amplifier U6, a resistor R9 and a resistor R19.

[0041] Preferably, pins 1-4 of the control chip U2 are respectively connected to ground, one end of the switch S2, one end of the switch S1 and 5V, pins 6 and 8 of the control chip U2 are connected to the feed motor B2, pin 5 of the control chip U2 is connected to the common end of the relay K1, the normally open and normally closed ends of the relay K1 are respectively connected to 24V and 12V, the positive and negative poles of the coil of the relay K1 are respectively connected to 12V and the collector of the transistor Q1, the positive and negative poles of the coil of the relay K1 are connected to the diode D7, the emitter and base of the transistor Q1 are respectively grounded and connected to pin 2 of the control chip U2 through the resistor R5, pin 7 of the control chip U2 is connected to resistors R8 and one end of R7, the other end of the resistor R7 is grounded, the other end of the resistor R8 is connected to pin 5 of the amplifier U6, the pin 6 of the amplifier U6 is grounded through the resistor R9, pins 2-4 and 8 of the amplifier U6 are respectively grounded and 12V, and the 6 and 7 pins of the amplifier U6 are connected in parallel with the resistor R19.

[0042] It can be understood that when pin 3 of control chip U2 is high and pin 2 is low, feed motor B2 rotates forward, driving the drill spindle downward to drill. While feed motor B2 is running, sampling resistor R7 senses the feed motor current, which is amplified 20 times by operational amplifier U6 and output from pin 7 of U6. When pin 3 of control chip U2 is low and pin 2 is high, feed motor B2 rotates in reverse, driving the drill spindle upward and back. At this time, because pin 2 of control chip U2 is high, transistor Q1 conducts, relay K1 activates, and the supply voltage of control chip U2 is converted from 12V to 24V, increasing the speed of feed motor B2 and accelerating the backing time.

[0043] In an embodiment of the present application, the limit switch control circuit module includes: diode D14, resistor R13, optocoupler U7, optocoupler U8, optocoupler U9, optocoupler U8, thyristor Q5, resistor R17, resistor R19, capacitor C12, resistor R14, resistor R18, transistor Q2, resistor R20, optocoupler U10, transistor Q4, resistor R16, resistor R15, resistor R32, resistor R23, limit switch P5, limit switch P2, diode D15, resistor R28, electrolytic capacitor C13, transistor Q3, optocoupler U5, thyristor Q3, optocoupler U12, resistor R29, thyristor Q3, capacitor C14, resistor R30, capacitor C15, resistor R31, optocoupler U11, optocoupler U12, resistor R34 and resistor R33.

[0044] As a preferred embodiment, the L1 terminal of the magnetic switch P4 is connected to the cathode of the diode D14, the anode of the diode D14 is connected to the 2nd pin of the optocoupler U7 through the resistor R13, the 2nd pin of the optocoupler U8 is connected to the 1st pin of the optocoupler U7, the 2nd pin of the optocoupler U9 is connected to the 1st pin of the optocoupler U8, the 1st pin of the optocoupler U9 is connected to the N1 terminal of the magnetic switch P4, the 3rd and 4th pins of the optocoupler U9 are respectively connected to the positive electrode of the thyristor Q5 and 12V, the 3rd and 4th pins of the optocoupler U8 are respectively grounded and one end of the resistors R17 and R19, the other end of the resistor R19 is connected to 12V, and the capacitor C12 is connected in parallel with the resistor R19. The 3rd and 4th pins of the optocoupler U7 are connected to the ground and one end of the resistors R14 and R18 respectively. The other end of the resistor R18 is connected to 12V. The other end of the resistor R14 is connected to the base of the transistor Q2. The emitter and collector of the transistor Q2 are grounded and connected to the 2nd pin of the optocoupler U10 through the resistor R20. The 1st pin of the optocoupler U10 is connected to 12V. The collector of the transistor Q4 is connected to the ground through the resistors R16 and R15. One end of the switch S1 is connected to the midpoint of the resistors R15 and R16. The other end of the switch S1 is connected to the 3rd pin of the optocoupler U10, one end of the switch S2 and one end of the resistor R32. The 4th foot of the optocoupler U10 is connected to 12V through the resistor R23, the 2nd foot of the limit switches P5 and P2 is connected to 12V, the normally closed end of the limit switch P5 is connected to the positive electrode of the diode D15, the negative electrode of the diode D15 is connected to the ground through the resistor R28, the positive and negative electrodes of the electrolytic capacitor C13 are connected to the negative electrode of the diode D15 and the base of the transistor Q3 respectively, the collector and emitter of the transistor Q6 are connected to the 1st foot of the optocoupler U5 and the ground respectively, the normally open end of the limit switch P5 is connected to the positive electrode of the thyristor Q3 and the 4th foot of the optocoupler U12, the normally closed end of the limit switch P2 is connected to the positive electrode of the thyristor Q3 and the 4th foot of the optocoupler U12, and the normally closed end of the limit switch P2 is connected to the positive electrode of the thyristor Q3 and the ground through the resistor R 29 is connected to the base of the thyristor Q3 and one end of the capacitor C14, the other end of the capacitor C14 is grounded, the cathode of the thyristor Q3 is grounded via the resistor R30, the capacitor C15 is connected in parallel with the resistor R30, the cathode of the thyristor Q3 is connected to pin 1 of the optocoupler U11 via the resistor R31, the 2nd to 4th pins of the optocoupler U11 are respectively connected to the 1st pin of the optocoupler U12, the ground and the 3rd pin of the motor control chip, the other end of the switch S2 is connected to the 2nd pin of the motor control chip U2, the other end of the switch S2 is grounded via the resistors R34 and R33, and the midpoint of the resistors R34 and R33 is connected to the 3rd pin of the optocoupler U12.

[0045] It's easy to understand that when main motor B1 starts, a voltage difference forms between L1 and N1, triggering optocouplers U7, U8, and U9. Optocoupler U9 triggers, and VDD reaches 12V. Optocoupler U8 triggers, placing transistor Q4 in a low-voltage state. Transistor Q4 conducts, and the 12V voltage is divided by resistors R16 and R15, causing IN3 (pin 3 of control chip U2) to reach a high voltage, and IN2 (pin 2 of control chip U2) to reach a high voltage. This allows feed motor B2 to rotate forward, driving the drill spindle downward. When main motor B1 is not running, optocoupler U7 is deactivated, transistor Q2's control pin reaches a high voltage, conducting, triggering optocoupler U10. When switch S1 is pressed, IN3 (pin 3 of control chip U2) reaches a high voltage, and U2's pin 2 reaches a low voltage. At this point, feed motor B2 alone rotates forward, driving the drill spindle downward. When switch S1 is open, pin 3 of control chip U2 reaches a low voltage, stopping feed motor B2. Similarly, when switch S2 is pressed, feed motor B2 retracts upward; when it is disconnected, feed motor B2 stops. When optocoupler U7 triggers, the control electrode of transistor Q2 reaches a low voltage, rendering transistor Q2 non-conductive and optocoupler U10 non-triggered. Therefore, whether switches S1 and S2 are pressed, feed motor B2 remains unchanged. When feed motor B2 moves downward, triggering switch P2, pin 2 of the travel switch is briefly connected to the NC terminal. The control electrode of thyristor Q3 reaches a high voltage, turning on the thyristor Q3 and triggering optocouplers U11 and U12. The voltage at IN3 (pin 3 of control chip U2) drops to a low voltage. Simultaneously, IN2, via the output of optocoupler U12, reaches a high voltage. Feed motor B2 reverses, driving the drill spindle upward. When the drill spindle retracts upward to its top and contacts travel switch P5, the positive terminal of thyristor Q3 disconnects from the 12V supply, disconnecting optocouplers U11 and U12, and thus stopping feed motor B2. Simultaneously, pin 2 of travel switch P5 connects to the Nc terminal, triggering a pulse on capacitor C13 that briefly turns on transistor Q6. This briefly turns OFF to a high voltage, deactivating optocoupler U5 and disconnecting the KA terminal of magnetic switch P4. This turns off feed motor B2 and main motor B1.

[0046] In an embodiment of the present application, the feed motor overcurrent protection circuit module includes: a diode D19, an operational amplifier U6, a resistor R22, a comparator U15, a resistor R46, a resistor R47, a resistor R48 and a diode D21.

[0047] Specifically, the anode of diode D19 is connected to pin 7 of operational amplifier U6, the cathode of diode D19 is connected to pin 5 of comparator U15 via resistor R22, pin 6 of comparator U15 is connected to resistors R46 and R47, the other end of resistor R46 is grounded, the other end of resistor R47 is connected to 5V, pin 7 of comparator U15 is connected to the anode of diode D21 via resistor R48, and the cathode of diode D21 is connected to the positive electrode of electrolytic capacitor C13.

[0048] It can be understood that the amplified value of the induced current of the feed motor B2 is input to the 5th pin of the comparator U15 through the diode D19 and the resistor R22. When the induced current increases to the set value, the 7th pin of the comparator U15 outputs a high voltage to the capacitor C13, forming a pulse, briefly turning on the transistor Q6, and disconnecting the main motor B1 and the feed motor B2.

[0049] In an embodiment of the present application, the main motor drilling and retraction circuit module includes: resistor R43, capacitor C19, resistor R45, resistor R44, resistor R49, comparator U14, diode D18, diode D19, resistor R21, resistor R24, resistor R25, resistor R26, thyristor Q5, resistor R40, resistor R39, diode D17, comparator U14, resistor R38 and resistor R37.

[0050] Preferably, pin 3 of the comparator U15 is connected to the cathode of the diode D20 via a resistor R43 and to ground via a capacitor C19, pin 2 of the comparator U15 is connected to ground via a resistor R45, pins 4 and 8 of the comparator U15 are connected to ground and 12V respectively, pins 1 and 2 of the comparator U15 are connected in parallel with a resistor R44, pin 1 of the comparator U15 is connected to pin 2 of the comparator U14 via a resistor R49, the anode of the diode D18 is connected to the anode of the diode D19, the cathode of the diode D18 is connected to pin 3 of the comparator U13 via a resistor R21, and pin 2 of the comparator U13 is connected to 5V via a resistor R24 ​​and to ground via a resistor R25 respectively. Pin 1 of the comparator U13 is connected to the control electrode of the thyristor Q5 through the resistor R26, the positive electrode of the thyristor Q5 is connected to the 3rd pin of the optocoupler U9, and the negative electrode of the thyristor Q5 is grounded through the resistor R40. Pin 1 of the comparator U14 is connected to the positive electrode of the diode D17 through the resistor R39, and the negative electrode of the diode D17 is connected to the normally closed end of the travel switch P2. Pin 2 of the comparator U14 is connected to the positive electrode of the electrolytic capacitor C16, and the negative electrode of the electrolytic capacitor C16 is grounded. Pin 3 of the comparator U14 is respectively connected to the ground through the resistor R38 and to 5V through the resistor R37. Pins 4-6 of the comparator U14 are grounded, and pin 8 of the comparator U14 is connected to the negative electrode of the thyristor Q5.

[0051] When the drill spindle contacts the cut metal, the resistance of feed motor B2 increases, causing the current to increase. When the sampled and amplified induced voltage reaches the set value, comparator U13's output pin 1 outputs a high voltage, triggering thyristor Q5, which powers comparator U14. At this point, comparator U14's pin 2 is connected to the amplified induced voltage of main motor B1, and pin 3 is connected to the set voltage. When main motor B1 is drilling, the induced voltage is relatively high, so the voltage at pin 2 is greater than the voltage at pin 3, and output pin 1 outputs a low voltage. As main motor B1 penetrates the metal, the induced voltage decreases. When it falls below the set value, comparator U14's pin 1 outputs a high voltage, triggering thyristor Q3, which reverses feed motor B2 and drives the drill spindle upward. When the drill spindle reaches its top end and contacts travel switch P5, both main motor B1 and feed motor B2 stop operating.

[0052] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any form, and any technical solutions obtained by equivalent replacement or equivalent transformation fall within the scope of protection of the present invention.

Claims

1. An automatic feed magnetic drilling rig control circuit, used to control the main motor B1 and feed motor B2, characterized in that: The automatic feed magnetic base drilling rig control circuit includes: power supply circuit module, magnetic base power supply circuit module, magnetic switch self-locking circuit module, main motor overcurrent protection circuit module, feed motor control circuit module, travel switch control circuit module, feed motor overcurrent protection circuit module and main motor drilling and retraction circuit module; The power circuit module supplies power to the automatic feed magnetic drilling rig control circuit; The power supply circuit module includes: rectifier bridge D4, thermistor NTC1, safety capacitor C7, resistor R3, diode D3, capacitor C6, resistor R4, power supply chip U1, transformer P1, capacitor C10, electrolytic capacitor C9, electrolytic capacitor C3, optocoupler U3, resistor R1, Zener diode D8, capacitor C8, diode D2, diode D5, diode D1, electrolytic capacitor C1, inductor L1, electrolytic capacitor C5, electrolytic capacitor C2, capacitor C4, resistor R2, light-emitting diode D6 and three-terminal voltage regulator VR1; The power supply is 220V AC, the 220V phase line L is connected to pin 1 of the input terminal of the rectifier bridge D4, the 220V neutral line N is connected to pin 2 of the input terminal of the rectifier bridge D4 through the thermistor NTC1, the input terminal of the rectifier bridge D4 is connected in parallel with the safety capacitor C7, the output terminal of the rectifier bridge D4 is connected to the negative electrode of the diode D3 through the resistor R3, the positive electrode of the diode D3 is connected to the capacitor C6 and one electrode of the resistor R4, the capacitor C6 and the other electrode of the resistor R4 are connected and connected to pins 5-8 of the power chip U1 and pin 1 of the transformer P1, the 1st and 2nd pins of the power chip U1 are connected and connected to the capacitor C10, the negative electrode of the electrolytic capacitor C9 and the 4th pin of the output terminal of the rectifier bridge D4, the output terminal of the rectifier bridge D4 is connected in parallel with the electrolytic capacitor C3, the other end of the capacitor C10 is connected to pin 3 of the power chip U1 and pin 3 of the optocoupler U3, the 4th pin of the power chip U1 is connected to the 4th pin of the optocoupler U3 and the positive electrode of the electrolytic capacitor C9 , Pin 1 and Pin 2 of the optocoupler U3 are connected to one end of the resistor R1 and the cathode of the Zener diode D8 respectively, the anode of the Zener diode D8 is connected to the power ground, the output terminal 4 of the rectifier bridge D4 is connected to the ground and the capacitor C8, the 3rd pin of the transformer P1 is connected to the anodes of the diodes D2 and D5, the 4th pin of the transformer P1 is connected to the anode of the electrolytic capacitor C1 via the diode D1, the cathode of the electrolytic capacitor C1 is grounded, and the 5th pin of the transformer P1 is grounded; the other end of the resistor R1 is connected to 12V, the cathodes of the diodes D2 and D5 are connected to one end of the inductor L1 and the anode of the electrolytic capacitor C5, the cathode of the electrolytic capacitor C5 is grounded, the other end of the inductor L1 is connected to 12V, the electrolytic capacitor C2 and the capacitor C4 are connected between 12V and the ground, the 12V is connected to the anode of the light-emitting diode D6 via the resistor R2, the cathode of the light-emitting diode D6 is grounded, the input end of the three-terminal voltage regulator VR1 is connected to 12V, the output end is connected to 5V, and the ground end is grounded; The main motor drilling and retraction circuit module includes: resistor R43, capacitor C19, resistor R45, resistor R44, resistor R49, comparator U14, diode D18, diode D19, resistor R21, resistor R24, resistor R25, resistor R26, thyristor Q5, resistor R40, resistor R39, diode D17, comparator U14, resistor R38 and resistor R37; Pin 3 of comparator U15 is connected to the cathode of diode D20 via resistor R43 and to ground via capacitor C19. Pin 2 of comparator U15 is connected to ground via resistor R45. Pins 4 and 8 of comparator U15 are connected to ground and 12V respectively. Pins 1 and 2 of comparator U15 are connected in parallel with resistor R44. Pin 1 of comparator U15 is connected to pin 2 of comparator U14 via resistor R49. The anode of diode D18 is connected to the anode of diode D19. The cathode of diode D18 is connected to pin 3 of comparator U13 via resistor R21. Pin 2 of comparator U13 is connected to 5V and to ground via resistor R25 respectively via resistor R24. Pin 1 of the comparator U13 is connected to the control electrode of the thyristor Q5 via resistor R26, the positive electrode of the thyristor Q5 is connected to pin 3 of the optocoupler U9, and the negative electrode of the thyristor Q5 is grounded via resistor R40. Pin 1 of the comparator U14 is connected to the positive electrode of the diode D17 via resistor R39, and the negative electrode of the diode D17 is connected to the normally closed end of the travel switch P2. Pin 2 of the comparator U14 is connected to the positive electrode of the electrolytic capacitor C16, and the negative electrode of the electrolytic capacitor C16 is grounded. Pin 3 of the comparator U14 is respectively grounded via resistor R38 and connected to 5V via resistor R37. Pins 4-6 of the comparator U14 are grounded, and pin 8 of the comparator U14 is connected to the negative electrode of the thyristor Q5.

2. The automatic feeding magnetic drilling rig control circuit according to claim 1, characterized in that: The magnetic base power supply circuit module includes: magnetic base P3, diode D9, diode D10, diode D13, rectifier bridge D12, diode D11 and diode D9; The positive pole of the magnetic base P3 is connected to the negative pole of the diode D9, the positive pole of the diode D9 is connected to the negative pole of the diode D10, the positive pole of the diode D10 is connected to the negative pole of the diode D13, the negative pole of the diode D13 is connected to the input end of the rectifier bridge D12 and the 220V neutral line N, the negative pole of the magnetic base P3 is connected to the negative pole of the rectifier bridge D12 and the positive pole of the diode D11, and the negative pole of the diode D11 is connected to the negative pole of the diode D9.

3. The automatic feeding magnetic drilling rig control circuit according to claim 2, characterized in that: The magnetic switch self-locking circuit module includes: optocoupler U4, resistor R6, magnetic switch P4, bidirectional thyristor T1, resistor R12, optocoupler U5, capacitor C11 and resistor R11; Pin 1 of the optocoupler U4 is connected to the positive electrode of the diode D10, pin 2 of the optocoupler U4 is connected to the negative electrode of the diode D9 via the resistor R6, pin 6 of the optocoupler U4 is connected to the KA electrode of the magnetic switch P4 and the T2 electrode of the bidirectional thyristor T1, pin 4 of the optocoupler U4 is connected to the 6 pin of the optocoupler U5 via the resistor R12, pin 4 of the optocoupler U5 is connected to the control electrode of the thyristor T1 and one electrode of the capacitor C11, the other electrode of the capacitor C11 is connected to the T1 electrode of the thyristor T1 and to the positive electrode of the diode D13, pin 1 and pin 2 of the optocoupler U5 are connected to 12V and ground respectively via the resistor R11, the output end of the magnetic switch P4 is connected in parallel with the main motor B1, and the input end is connected to the 220V power supply.

4. The automatic feeding magnetic drilling rig control circuit according to claim 3, characterized in that: The main motor overcurrent protection circuit module includes: mutual inductor L2, diode D20, resistor R41, comparator U13, electrolytic capacitor C18, resistor R42, resistor R42, resistor R35, resistor R36, comparator U13, resistor R27 and diode D16; One end of the mutual inductor L2 is grounded, and the other end is connected to the positive electrode of the diode D20. The negative electrode of the diode D20 is connected to the 5th pin of the comparator U13 via the resistor R41. The positive electrode of the electrolytic capacitor C18 is connected to the positive electrode of the diode D20 and one end of the resistor R42. The negative electrode of the electrolytic capacitor C18 is connected to the other end of the resistor R42 and grounded. 5V is connected to the resistor R36 via the resistor R35. The other end of the resistor R36 is grounded. The 6th pin of the comparator U13 is connected to the midpoint of the resistors R35 and R36. The 7th pin of the comparator U13 is connected to the positive electrode of the diode D16 via the resistor R27. The 4th pin and the 8th pin of the comparator U13 are grounded and 12V respectively.

5. The automatic feeding magnetic drilling rig control circuit according to claim 4, characterized in that: The feed motor control circuit module includes: control chip U2, switch S2, switch S1, relay K1, transistor Q1, diode D7, resistor R5, resistor R8, resistor R7, amplifier U6, resistor R9 and resistor R19; Pins 1-4 of the control chip U2 are connected to ground, one end of the switch S2, one end of the switch S1 and 5V respectively. Pins 6 and 8 of the control chip U2 are connected to the feed motor B2. Pin 5 of the control chip U2 is connected to the common end of the relay K1. The normally open and normally closed ends of the relay K1 are connected to 24V and 12V respectively. The positive and negative poles of the coil of the relay K1 are connected to 12V and the collector of the transistor Q1 respectively. The positive and negative poles of the coil of the relay K1 are connected to the diode D7. The emitter and base of the transistor Q1 are grounded and connected to pin 2 of the control chip U2 through resistor R5 respectively. Pin 7 of the control chip U2 is connected to resistors R8 and one end of R7. The other end of resistor R7 is grounded. The other end of resistor R8 is connected to pin 5 of the amplifier U6. Pin 6 of the amplifier U6 is grounded through resistor R9. Pins 2-4 and 8 of the amplifier U6 are grounded and 12V respectively. Pins 6 and 7 of the amplifier U6 are connected in parallel with resistor R19.

6. The automatic feeding magnetic drilling rig control circuit according to claim 5, characterized in that: The limit switch control circuit module includes: diode D14, resistor R13, optocoupler U7, optocoupler U8, optocoupler U9, optocoupler U8, thyristor Q5, resistor R17, resistor R19, capacitor C12, resistor R14, resistor R18, transistor Q2, resistor R20, optocoupler U10, transistor Q4, resistor R16, resistor R15, resistor R32, resistor R23, limit switch P5, limit switch P2, diode D15, resistor R28, electrolytic capacitor C13, transistor Q3, optocoupler U5, thyristor Q3, optocoupler U12, resistor R29, thyristor Q3, capacitor C14, resistor R30, capacitor C15, resistor R31, optocoupler U11, optocoupler U12, resistor R34 and resistor R33; The L1 terminal of the magnetic switch P4 is connected to the cathode of the diode D14, the anode of the diode D14 is connected to the 2nd pin of the optocoupler U7 through the resistor R13, the 2nd pin of the optocoupler U8 is connected to the 1st pin of the optocoupler U7, the 2nd pin of the optocoupler U9 is connected to the 1st pin of the optocoupler U8, the 1st pin of the optocoupler U9 is connected to the N1 terminal of the magnetic switch P4, the 3rd and 4th pins of the optocoupler U9 are connected to the positive electrode of the thyristor Q5 and 12V respectively, the 3rd and 4th pins of the optocoupler U8 are connected to the ground and one end of the resistors R17 and R19 respectively, the other end of the resistor R19 is connected to 12V, the capacitor C12 is connected in parallel with the resistor R19, the 3rd pin of the optocoupler U7 Pin 1 and 2 are connected to ground and one end of resistors R14 and R18 respectively. The other end of resistor R18 is connected to 12V. The other end of resistor R14 is connected to the base of transistor Q2. The emitter and collector of transistor Q2 are grounded and connected to pin 2 of optocoupler U10 through resistor R20 respectively. Pin 1 of optocoupler U10 is connected to 12V. The collector of transistor Q4 is connected to ground through resistors R16 and R15. One end of switch S1 is connected to the midpoint of resistors R15 and R16. The other end of switch S1 is connected to pin 3 of optocoupler U10, one end of switch S2 is connected to one end of resistor R32, and the optocoupler U10 is connected to the 12V supply voltage. Pin 4 is connected to 12V via resistor R23, pin 2 of limit switches P5 and P2 is connected to 12V, the normally closed end of limit switch P5 is connected to the positive electrode of diode D15, the negative electrode of diode D15 is connected to ground via resistor R28, the positive and negative electrodes of electrolytic capacitor C13 are connected to the negative electrode of diode D15 and the base of transistor Q3 respectively, the collector and emitter of transistor Q6 are connected to pin 1 of optocoupler U5 and ground respectively, the normally open end of limit switch P5 is connected to the positive electrode of thyristor Q3 and pin 4 of optocoupler U12, the normally closed end of limit switch P2 is connected to The base of the thyristor Q3 is connected to one end of the capacitor C14, the other end of the capacitor C14 is grounded, the cathode of the thyristor Q3 is grounded via the resistor R30, the capacitor C15 is connected in parallel with the resistor R30, the cathode of the thyristor Q3 is connected to pin 1 of the optocoupler U11 via the resistor R31, the pins 2-4 of the optocoupler U11 are respectively connected to pin 1 of the optocoupler U12, the ground and the pin 3 of the motor control chip, the other end of the switch S2 is connected to pin 2 of the motor control chip U2, the other end of the switch S2 is grounded via the resistors R34 and R33, and the midpoint of the resistors R34 and R33 is connected to pin 3 of the optocoupler U12.

7. The automatic feeding magnetic drilling rig control circuit according to claim 6, characterized in that: The feed motor overcurrent protection circuit module includes: diode D19, operational amplifier U6, resistor R22, comparator U15, resistor R46, resistor R47, resistor R48 and diode D21; The anode of diode D19 is connected to pin 7 of operational amplifier U6, the cathode of diode D19 is connected to pin 5 of comparator U15 via resistor R22, pin 6 of comparator U15 is connected to resistors R46 and R47, the other end of resistor R46 is grounded, the other end of resistor R47 is connected to 5V, pin 7 of comparator U15 is connected to the anode of diode D21 via resistor R48, and the cathode of diode D21 is connected to the positive electrode of electrolytic capacitor C13.

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