Suspension type monorail vehicle air compressor control circuit and control method

Abstract

The invention discloses a suspension type monorail vehicle air compressor control circuit and a control method, the control circuit comprises a temperature detection module, an air compressor cooling fan start-stop circuit and an air compressor start-stop circuit, the air compressor cooling fan start-stop circuit is connected with the temperature detection module, the temperature detection module converts the oil temperature of the air compressor into an electric signal, and the electric signal is sent to the air compressor cooling fan start-stop circuit; the air compressor cooling fan starting and stopping circuit controls a fan switch through a relay and an analog quantity conversion switching quantity relay, and the air compressor starting and stopping circuit adjusts the air pressure of a brake air circuit through the relay, a pressure switch, a contactor, the analog quantity conversion switching quantity relay and the like, so that automatic starting and stopping control over an air compressor is achieved. The control method is based on the control circuit. By means of a pure hard wire circuit control mode, control equipment needing programming does not need to be used, automatic heat dissipation equipment starting control, over-temperature protection control and the like of the air compressor are achieved, the safety of a mechanical braking system can be guaranteed to the maximum extent, and wide application prospects are achieved.

Description

Technical Field

[0001] The invention belongs to the field of engineering machinery circuit control, and in particular relates to a control circuit and a control method for an air compressor of a suspended monorail vehicle. Background Art

[0002] The suspended monorail vehicle uses columns to support the track beam in the air. The track beam is a steel box beam with an open bottom. The vehicle running mechanism runs along the track inside the box beam, and the car is suspended under the track.

[0003] Suspended monorail vehicles usually use electric brakes to provide braking force for the vehicle, so that the vehicle can slow down and stop according to system requirements. When the electric brake system fails during vehicle operation or the vehicle idles and slides, the mechanical brake system provides the vehicle with adjustable mechanical braking force; at the same time, the mechanical brake system is used for parking brakes and emergency brakes. The mechanical braking method of suspended monorail vehicles is air braking, which uses compressed air to push the piston in the brake cylinder so that the brake shoe presses against the track beam, generating friction to achieve braking. The function of the vehicle air compressor is to generate compressed air to provide a power source for the vehicle's braking system.

[0004] In order to ensure that the air compressor can provide a stable air source for the mechanical brake system, achieve coordinated work with the mechanical brake system, and ensure the reliability and safety of the air compressor, the design of the air compressor control circuit is crucial in the design of the entire vehicle system. Therefore, how to solve the design problem of the air compressor control circuit of the suspended monorail vehicle and maximize the safety, reliability and availability of the mechanical brake system is a problem that technicians in this field need to solve. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a control circuit and a control method for an air compressor of a suspended monorail vehicle, which can adjust the air pressure of the brake air circuit through pure hard-wire circuit control, realize automatic start and stop control of the air compressor, provide over-temperature protection control for the air compressor, etc.

[0006] To solve the above technical problems, the present invention provides the following technical solutions: A control circuit for an air compressor of a suspended monorail vehicle, comprising: a temperature detection module and an air compressor cooling fan start-stop circuit connected to the temperature detection module;

[0007] The temperature detection module includes: a temperature transmitter U3, and a signal isolator U4 connected to the temperature transmitter U3; the temperature transmitter U3 is used to detect the lubricating oil temperature of the air compressor M1, and convert the oil temperature signal into a current signal, the signal isolator U4 receives the current signal output by the temperature transmitter U3, and converts it into two equal current signals, and outputs one of the current signals to the start and stop circuit of the air compressor cooling fan;

[0008] The air compressor cooling fan start-stop circuit includes: analog quantity conversion switch quantity relay U5, relay K7, relay K8, and DC fan;

[0009] The analog quantity conversion switch relay U5 is connected to the signal isolator U4, and receives one of the current signals output from the signal isolator U4. The analog quantity conversion switch relay U5 is connected to relay K7 and relay K8 respectively. When the lubricating oil temperature of the air compressor M1 is greater than the first temperature preset value, the relay K7 coil is energized, and the DC fan M2 is energized and started; when the lubricating oil temperature of the air compressor M1 is lower than the second temperature preset value, the relay K8 coil is energized, and the DC fan M2 loses power and stops working.

[0010] Furthermore, the aforementioned suspended monorail vehicle air compressor control circuit further includes an air compressor start-stop circuit connected to the temperature detection module.

[0011] The air compressor start-stop circuit includes: analog quantity conversion switch relay U2, pressure switch U1, contactor K1, relay K2, relay K3, relay K4, delay relay K5, diode V1, air compressor M1, pump air circuit breaker F1;

[0012] The port IN+ and port GND of the analog conversion switch relay U2 are connected to the 9th and 10th points of the signal isolator U4 respectively. The analog conversion switch relay U2 receives another current signal output from the signal isolator U4.

[0013] The three sets of main contacts of contactor K1 are connected to the AC 380V external power supply and the air compressor M1 respectively, the contact 2 of the pump air circuit breaker F1 is connected to the positive pole of the DC 24V external power supply, and the contact 1 of the pump air circuit breaker F1 is connected to the contact 14 of the relay K2; the contacts 13 and 14 of the relay K2 are closed, the coil of the contactor K1 is energized, the main contacts of the contactor K1 are closed, and the air compressor M1 is started;

[0014] Point 1 of the pressure switch U1 is connected to the positive pole of the DC 24V external power supply, and point 2 of the pressure switch U1 is connected to the positive pole of the diode V1; the negative pole of the diode V1 is connected to the contact 12 of the relay K4;

[0015] The normally closed contacts of relay K4 and time delay relay K5 are connected to the A1 point of relay K2, the A1 point of time delay relay K5 is connected to the A2 point of relay K4, the contact 11 of relay K4 is connected to the contact 16 of time delay relay K5, the contact 15 of time delay relay K5 is connected to the A1 end of the coil of relay K2, and the A2 end of relay K2 is connected to the negative pole of the DC24V external power supply; when the pressure switch U1 detects that the brake line pressure is lower than the first pressure preset value, the point 1 and the point 2 of the pressure switch U1 are connected, the coil of relay K2 is energized, the contacts 13 and 14 of relay K2 are closed, the coil of contactor K1 is energized, the main contacts of contactor K1 are closed, and the air compressor M1 is started;

[0016] Relay K3 is connected to the DC 24V external power supply and point 2 of the pressure switch U1 respectively; when the pressure switch U1 detects that the pressure is higher than the second pressure preset value, point 1 and point 2 of the pressure switch U1 are disconnected, the coil of relay K3 loses power, contacts 11 and 12 of relay K3 are closed, contact K1+ of the analog conversion switch relay U2 is connected to contact 11 of relay K3, and contact 12 of relay K3 is connected to the positive pole of the DC 24V external power supply; contact K1- of the analog conversion switch relay U2 is connected to point A3 of the delay relay K5; when the air compressor lubricating oil temperature is higher than the third temperature preset value, contact K1 of the analog conversion switch relay U2 is closed, the coil of the delay relay K5 is energized, and after a preset time, contacts 15 and 16 of the delay relay K5 are disconnected, the coil of relay K2 loses power, contacts 13 and 14 of relay K2 are disconnected, the coil of contactor K1 loses power, and the air compressor M1 stops working;

[0017] The A1 point of relay K4 is connected to the contact K2- of the analog quantity conversion switch relay U2, and the A2 point of relay K4 is connected to the negative pole of the DC 24V external power supply. When the oil temperature is greater than the protection temperature threshold, the contacts K2+ and K2- of the analog quantity conversion switch relay U2 are closed, and the A1 point of relay K4 is connected to the contact K2- of the analog quantity conversion switch relay U2, and the K2+ contact is connected to the positive pole of the DC 24V external power supply. The coil of relay K4 is energized, contacts 11 and 12 of relay K4 are disconnected, the coil of relay K2 is de-energized, contacts 13 and 14 of relay K2 are disconnected, the coil of contactor K1 is de-energized, and the air compressor M1 stops working.

[0018] Further, the aforementioned air compressor cooling fan start-stop circuit is specifically: the 11th point and the 12th point of the signal isolator U4 are correspondingly connected to the port IN+ and the port GND of the analog conversion switch relay U5;

[0019] The contact K1+ of the analog quantity conversion switch relay U5 is connected to the positive pole of the DC 24V external power supply, and the contact K1- is connected to the A2 point of the relay K7. When the lubricating oil temperature of the air compressor is greater than the first temperature preset value, the contact K1+ and the contact K1- are closed, that is, the contact K1+ and the contact K1- are connected, the relay K7 coil is energized, the contact 15 and the contact 16 of the relay K7 are closed, the DC fan M2 is powered by DC24V, and the fan starts to work;

[0020] The contact K2+ of the analog quantity conversion switch relay U5 is connected to the positive pole of the DC 24V external power supply, the contact K2- is connected to the A1 point of the relay K8, and the A2 point of the relay K8 is connected to the negative pole of the DC 24V external power supply. When the lubricating oil temperature of the air compressor M1 is lower than the second temperature preset value, the contact K2+ and the contact K2- are closed, that is, the contact K2+ and the contact K2- are connected, the coil of the relay K8 is energized, the contacts 11 and 12 of the relay K8 are disconnected, the coil of the relay K7 is de-energized, the contacts 15 and 16 of the relay K7 are disconnected, the DC fan M2 loses the DC24V power, and the DC fan M2 stops working.

[0021] Furthermore, the aforementioned suspended monorail vehicle air compressor control circuit also includes a strong pump air switch S1, which manually starts the DC fan M2 through the pump air circuit breaker F1 and the forced pump air button S. Specifically, the contact 1 of the pump air circuit breaker F1 is connected to the contact 13 of the forced pump air button S and the contact 14 of the relay K2, and the contact 14 of the forced pump air button S is connected to the A1 point of the contactor K1 and the contact 13 of the relay K2.

[0022] Furthermore, the aforementioned first temperature preset value is 95°C, the second temperature preset value is 90°C, the third temperature preset value is 80°C, and the protection temperature threshold is 100°C.

[0023] Furthermore, in the aforementioned air compressor control circuit based on a suspended monorail vehicle, when point 1 and point 2 of the pressure switch U1 are connected and the coil of the relay K2 is energized, contacts 17 and 18 of the relay K2 are closed, and the coil of the relay K2 remains energized through contacts 17 and 18.

[0024] Furthermore, the aforementioned air compressor control circuit based on a suspended monorail vehicle also includes: starting a forced pump air button to energize the three-phase contactor K1 coil of the air compressor, forcing the air compressor M1 to work.

[0025] The present invention also provides an air compressor control method based on a suspended monorail vehicle air compressor control circuit, which is characterized by comprising the following steps:

[0026] S1, pressure switch U1 detects the air pressure of the brake pipeline. When the air pressure of the brake pipeline is lower than the first preset air pressure value, the first point position and the second point position of the pressure switch U1 are connected, the coil of the relay K2 is energized, the 24V coil of the contactor K1 is energized, the three-phase contacts of the contactor K1 are closed, and the air compressor M1 starts to work;

[0027] S2. After the air compressor M1 starts working, the air pressure in the brake system air circuit increases. When the pressure switch U1 detects that the air pressure is greater than the second preset air pressure value, the first point position and the second point position of the pressure switch U1 are disconnected, and the normally closed contact of the relay K3 is closed;

[0028] S3, the temperature transmitter U3 detects the lubricating oil temperature of the air compressor, converts the oil temperature signal into a current signal, and outputs the current signal to the signal isolator U4. The signal isolator U4 receives the current signal output by the temperature transmitter U3, and converts the current signal into two equal current signals LS1 and LS2;

[0029] S4, the signal isolator U4 outputs the current signal LS1 to the analog quantity to switch quantity relay U2, and outputs the current signal LS2 to the analog quantity to switch quantity relay U5;

[0030] S5. According to the relationship between temperature and current defined by the temperature transmitter U3, the current threshold corresponding to the third temperature preset value and the protection temperature threshold is set in the analog quantity to switch quantity relay U2, and the current threshold corresponding to the first temperature preset value and the second temperature preset value is set in the analog quantity to switch quantity relay U5;

[0031] S6, when the lubricating oil temperature of the air compressor is detected to be greater than the third temperature preset value, the contact K1+ and contact K1- of the analog quantity to switch quantity relay U2 are closed, and the coil of the delay relay K5 is energized;

[0032] S7, set the delay time of the delay relay K5. When the delay relay K5 coil is energized beyond the preset value, the normally closed contacts 15 and 16 of the delay relay K5 are disconnected, the relay K2 coil loses power, the relay K2 contacts 13 and 14 are disconnected, and the air compressor stops working;

[0033] S8, when the lubricating oil temperature of the air compressor is detected to be greater than the first temperature preset value, the contact K1+ and contact K1- of the analog switch relay U5 are closed, the coil of the relay K7 is energized, the contact 15 and contact 16 of the relay K7 are closed, the DC fan is energized to work, and the air compressor is cooled; at the same time, the contact 13 and contact 14 of the relay K7 are closed, forming a self-locking circuit to power the coil of the relay K7;

[0034] S9, when the lubricating oil temperature of the air compressor is detected to be less than the first temperature preset value, the contact K1+ and contact K1- of the analog quantity to switch quantity relay U5 are disconnected, and the coil of the relay K7 is powered through the self-locking circuit, and the DC fan remains in the working state; S10, when the lubricating oil temperature of the air compressor is detected to be less than the second temperature preset value, the contact K2+ and contact K2- of the analog quantity to switch quantity relay U5 are closed, the coil of the relay K8 is powered, the contact 11 and contact 12 of the relay K8 are disconnected, the coil of the relay K7 is de-energized, the contact 13, contact 14, contact 15, and contact 16 of the relay K7 are disconnected, and the DC fan stops working;

[0035] S11. When the lubricating oil temperature of the air compressor is detected to be greater than the protection temperature threshold, the coil of relay K4 is energized, contacts 11 and 12 of relay K4 are disconnected, the coil of relay K2 is de-energized, and the air compressor stops working.

[0036] Furthermore, in the aforementioned air compressor control method based on the suspended monorail vehicle air compressor control circuit, in step S5, the relationship between temperature and current is specifically: the output current signal corresponding to the temperature range of -50 to 200°C is 4-20mA.

[0037] Furthermore, in the aforementioned air compressor control method based on the suspended monorail vehicle air compressor control circuit, the first air pressure preset value is 8.5 bar, and the second air pressure preset value is 9.5 bar.

[0038] Compared with the prior art, the beneficial technical effects of the present invention using the above technical solution are as follows:

[0039] The invention can realize automatic start and stop control of the air compressor, target operating temperature control, automatic condensate removal control, automatic start-up cooling device control and over-temperature protection control through pure hard-wired circuit control without the use of control equipment that requires programming, such as PLC, thereby maximizing the safety, reliability and availability of the mechanical braking system. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 The invention discloses a circuit diagram for starting and stopping the cooling fan of an air compressor.

[0041] Figure 2 It is the start-stop circuit diagram of the air compressor of the present invention. DETAILED DESCRIPTION

[0042] In order to better understand the technical content of the present invention, specific embodiments are given and described as follows in conjunction with the accompanying drawings.

[0043] Various aspects of the invention are described herein with reference to the accompanying drawings, in which many illustrative embodiments are shown. The embodiments of the invention are not limited to those described in the accompanying drawings. It should be understood that the invention is implemented by any of the various concepts and embodiments described above, as well as the concepts and embodiments described in detail below, because the concepts and embodiments disclosed in the invention are not limited to any implementation. In addition, some aspects disclosed in the invention may be used alone or in any appropriate combination with other aspects disclosed in the invention.

[0044] The control circuit design of the air compressor needs to meet the following requirements:

[0045] 1. According to the air pressure requirements of the mechanical brake system, the air compressor needs to be started when the air pressure is less than 8.5 bar to provide air source for the mechanical brake system.

[0046] 2. After the air compressor is started, the oil temperature of the air compressor needs to reach 80℃, because only when the oil temperature is around 80℃ can the air compressor work at maximum efficiency.

[0047] 3. When the oil temperature reaches 80°C after the air compressor is started, it needs to continue working for another 5 minutes in order to remove the condensed water in the air compressor.

[0048] 4. The air compressor will stop working when the air pressure of the brake system is greater than 9.5 bar and it has worked for 5 minutes as required above.

[0049] 5. When the oil temperature is detected to be too high during the operation of the air compressor, greater than 95°C, the air cooling system will be started, and when the temperature is less than 90°C, the air cooling system will be stopped.

[0050] 6. If the air compressor oil temperature continues to be too high, exceeding 100°C, stop the air compressor immediately.

[0051] 7. Under special circumstances, the air compressor can be manually forced to start.

[0052] Based on the above control circuit design requirements, the present invention provides a suspended monorail vehicle air compressor control circuit, referring to Figure 1 The control circuit includes: a temperature detection module and an air compressor cooling fan start-stop circuit connected to the temperature detection module; the main function is to control the start and stop of the air compressor cooling fan (the fan starts when the oil temperature is greater than 95°C and stops when the oil temperature is less than 90°C).

[0053] The temperature detection module includes: a temperature transmitter U3, and a signal isolator U4 connected to the temperature transmitter U3; the temperature transmitter U3 is used to detect the lubricating oil temperature of the air compressor M1, and convert the oil temperature signal into a current signal, the signal isolator U4 receives the current signal output by the temperature transmitter U3, and converts it into two equal current signals, and outputs one of the current signals to the start and stop circuit of the air compressor cooling fan;

[0054] The start and stop circuit of the cooling fan of the air compressor M1 includes: an analog conversion switch relay U5, a relay K7, a relay K8, and a DC fan; the analog conversion switch relay U5 is connected to the signal isolator U4, and receives one of the current signals output from the signal isolator U4, and the analog conversion switch relay U5 is connected to the relay K7 and the relay K8 respectively. When the lubricating oil temperature of the air compressor M1 is greater than 95°C, the coil of the relay K7 is energized, and the DC fan M2 is energized and started; when the lubricating oil temperature of the air compressor M1 is less than 90°C, the coil of the relay K8 is energized, and the DC fan M2 loses power and stops working.

[0055] The temperature transmitter U3 used in the present invention converts the temperature signal into a current signal. The temperature range is -50 to 200°C, and the corresponding output current signal is 4-20mA.

[0056] In the present invention, the air compressor needs to be controlled according to multiple temperature values, so one signal needs to be converted into two signals, that is, one current signal from the temperature transmitter is converted into two current signals through the signal isolator U4.

[0057] Two action threshold currents can be set inside the module of the analog-to-switch relay U2 through a potentiometer. When the input signal is greater than the set value 1, relay 1 is closed and K1 is turned on; when the input signal is greater than the set value 2, relay 2 is closed and K2 is turned on.

[0058] The two action threshold currents of the analog-to-switch relay U5 can be set by a potentiometer. When the input signal is greater than the set value 1, relay 1 is closed and K1 is turned on; when the input signal is less than the set value 2, relay 2 is closed and K2 is turned on.

[0059] The specific circuit for starting and stopping the cooling fan of the air compressor is as follows: the 11th and 12th points of the signal isolator U4 are connected to the port IN+ and the port GND of the analog conversion switch relay U5 respectively;

[0060] The contact K1+ of the analog quantity conversion switch relay U5 is connected to the positive pole of the DC 24V external power supply, and the contact K1- is connected to the A2 point of the relay K7. When the lubricating oil temperature of the air compressor is greater than the first temperature preset value, the contact K1+ and the contact K1- are closed, that is, the contact K1+ and the contact K1- are connected, the relay K7 coil is energized, the contacts 15 and 16 of the relay are closed, the DC fan M2 is powered by DC24V, and the fan starts to work;

[0061] The contact K2+ of the analog quantity conversion switch relay U5 is connected to the positive pole of the DC 24V external power supply, the contact K2- is connected to the A1 point of the relay K8, and the A2 point of the relay K8 is connected to the negative pole of the DC 24V external power supply. When the lubricating oil temperature of the air compressor M1 is lower than the second temperature preset value, the contact K2+ and the contact K2- are closed, that is, the contact K2+ and the contact K2- are connected, the coil of the relay K8 is energized, the contacts 11 and 12 of the relay K8 are disconnected, the coil of the relay K7 is de-energized, the contacts 15 and 16 of the relay K7 are disconnected, the DC fan M2 loses the DC24V power, and the fan stops working.

[0062] refer to Figure 2 The air compressor control circuit of a suspended monorail vehicle of the present invention also includes an air compressor start-stop circuit connected to the temperature detection module, and its main function is to control the start and stop of the air compressor and over-temperature protection.

[0063] The air compressor start-stop circuit includes: analog quantity conversion switch relay U2, pressure switch U1, contactor K1, relay K2, relay K3, relay K4, delay relay K5, diode V1, air compressor M1;

[0064] Pressure switch U1: used to manually adjust the threshold of the pressure switch. According to the requirements of the mechanical brake system, it is set that when the air pressure is less than 8.5 bar, point 1 and point 2 of the pressure switch U1 are connected, and when the air pressure is greater than 9.5 bar, point 1 and point 2 are disconnected. When the air pressure rises from 8.5 bar to 9.5 bar, point 1 and point 2 are in the connected state; when the air pressure drops from 9.5 bar to 8.5 bar, point 1 and point 2 are in the disconnected state.

[0065] The port IN+ and port GND of the analog conversion switch relay U2 are connected to the 9th and 10th points of the signal isolator U4 respectively. The analog conversion switch relay U2 receives another current signal output from the signal isolator U4.

[0066] The three sets of main contacts of contactor K1 are connected to the AC 380V external power supply and the air compressor M1 respectively, and the start and stop of the air compressor M1 are controlled by contactor K1; contact 2 of pump air circuit breaker F1 is connected to the positive pole of the DC 24V external power supply, and contact 1 of pump air circuit breaker F1 is connected to contact 14 of relay K2; contacts 13 and 14 of relay K2 are closed, the coil of contactor K1 is energized, the main contacts of contactor K1 are closed, and the air compressor M1 is started;

[0067] Point 1 of the pressure switch U1 is connected to the positive pole of the DC 24V external power supply, and point 2 of the pressure switch U1 is connected to the positive pole of the diode V1; the negative pole of the diode V1 is connected to the contact 12 of the relay K4; the contact 11 of the relay K4 is connected to the contact 16 of the delay relay K5, the contact 15 of the delay relay K5 is connected to the coil A1 end of the relay K2, and the A2 end of the relay K2 is connected to the negative pole of the DC24V external power supply. During the specific implementation, the delay time of the delay relay K5 is set to 5 minutes.

[0068] like Figure 1 As shown, the normally closed contacts of relay K4 and time delay relay K5 are connected to the A1 point of relay K2, the A1 point of time delay relay K5 is connected to the A2 point of relay K4, the contact 11 of relay K4 is connected to the contact 16 of time delay relay K5, the contact 15 of time delay relay K5 is connected to the A1 end of the coil of relay K2, and the A2 end of relay K2 is connected to the negative pole of the DC24V external power supply; when the pressure switch U1 detects that the brake line pressure is lower than the first pressure preset value, the point 1 and the point 2 of the pressure switch U1 are connected, the coil of relay K2 is energized, the contacts 13 and 14 of relay K2 are closed, the coil of contactor K1 is energized, the main contacts of contactor K1 are closed, and the air compressor M1 is started; when the point 1 and the point 2 of the pressure switch U1 are connected, when the coil of relay K2 is energized, the contacts 17 and 18 of relay K2 are closed, and the coil of relay K2 is kept energized through contacts 17 and 18.

[0069] Relay K3 is connected to the DC 24V external power supply and point 2 of the pressure switch U1 respectively; when the pressure switch U1 detects that the pressure is higher than 9.5bar, point 1 and point 2 of the pressure switch U1 are disconnected, the coil of relay K3 loses power, contacts 11 and 12 of relay K3 are closed, contact K1+ of the analog conversion switch relay U2 is connected to contact 11 of relay K3, and contact 12 of relay K3 is connected to the positive pole of the DC 24V external power supply; contact K1- of the analog conversion switch relay U2 is connected to point A3 of the delay relay K5. When the lubricating oil temperature of the air compressor is higher than 80℃, contact K1+ of the analog conversion switch relay U2 is closed, and the coil of the delay relay K5 is energized. After a preset time, contacts 15 and 16 of the delay relay K5 are disconnected, the coil of relay K2 loses power, contacts 13 and 14 of relay K2 are disconnected, the coil of contactor K1 loses power, and the air compressor M1 stops working;

[0070] The A1 point of relay K4 is connected to the contact K2- of the analog quantity conversion switch relay U2, and the A2 point of relay K4 is connected to the positive pole of the DC 24V external power supply. When the oil temperature is greater than the protection temperature threshold of 100℃, the contacts K2+ and K2- of the analog quantity conversion switch relay U2 are closed, and the A1 point of relay K4 is connected to the contact K2- of the analog quantity conversion switch relay U2, and the contact K2+ is connected to the positive pole of the DC 24V external power supply. The coil of relay K4 is energized, contacts 11 and 12 of relay K4 are disconnected, the coil of relay K2 is de-energized, contacts 13 and 14 of relay K2 are disconnected, the coil of contactor K1 is de-energized, and the air compressor M1 stops working.

[0071] The control circuit of the present invention also includes manually starting the DC fan M2 through the pump air circuit breaker F1 and the forced pump air button S, specifically: the contact 1 of the pump air circuit breaker F1 is connected to the contact 13 of the forced pump air button S and the contact 14 of the relay K2, and the contact 14 of the forced pump air button S is connected to the A1 point of the contactor K1 and the contact 13 of the relay K2. When the pump air circuit breaker F1 and the forced pump air button S are closed, the coil of the contactor K1 is energized, and the air compressor M1 is forced to start when necessary.

[0072] The above circuit involves meeting the seven requirements that need to be met in the control circuit design of the air compressor.

[0073] Another aspect of the present invention provides an air compressor control method based on a suspended monorail vehicle air compressor control circuit, comprising the following steps:

[0074] S1, pressure switch U1 detects the air pressure of the brake pipeline. When the air pressure of the brake pipeline is lower than the first preset air pressure value, the first point position and the second point position of the pressure switch U1 are connected, the coil of the relay K2 is energized, the 24V coil of the contactor K1 is energized, the three-phase contacts of the contactor K1 are closed, and the air compressor M1 starts to work;

[0075] S2. After the air compressor M1 starts working, the air pressure in the brake system air circuit increases. When the pressure switch U1 detects that the air pressure is greater than the second preset air pressure value of 9.5 bar, the first point position and the second point position of the pressure switch U1 are disconnected, and the normally closed contact of the relay K3 is closed;

[0076] S3, the temperature transmitter U3 detects the lubricating oil temperature of the air compressor, converts the oil temperature signal into a current signal, and outputs the current signal to the signal isolator U4. The signal isolator U4 receives the current signal output by the temperature transmitter U3, and converts the current signal into two equal current signals LS1 and LS2;

[0077] S4, the signal isolator U4 outputs the current signal LS1 to the analog quantity to switch quantity relay U2, and outputs the current signal LS2 to the analog quantity to switch quantity relay U5;

[0078] S5. According to the relationship between temperature and current defined by the temperature transmitter U3, the third temperature preset value 80°C and the current threshold 100°C corresponding to the protection temperature threshold are set in the analog quantity to switch quantity relay U2, and the first temperature preset value 95°C and the current threshold 90°C corresponding to the second temperature preset value are set in the analog quantity to switch quantity relay U5;

[0079] S6, when the lubricating oil temperature of the air compressor is detected to be greater than the third temperature preset value, the contact K1+ and contact K1- of the analog quantity to switch quantity relay U2 are closed, and the coil of the delay relay K5 is energized;

[0080] S7, set the delay time of the delay relay K5 to 5 minutes. When the delay relay K5 coil is energized for more than 5 minutes, the normally closed contacts 15 and 16 of the delay relay K5 are disconnected, the relay K2 coil loses power, the relay K2 contacts 13 and 14 are disconnected, and the air compressor stops working;

[0081] S8, when the lubricating oil temperature of the air compressor is detected to be greater than the first temperature preset value, the contact K1+ and contact K1- of the analog switch relay U5 are closed, the coil of the relay K7 is energized, the contact 15 and contact 16 of the relay K7 are closed, the DC fan is energized to work, and the air compressor is cooled; at the same time, the contact 13 and contact 14 of the relay K7 are closed, forming a self-locking circuit to power the coil of the relay K7;

[0082] S9, when the lubricating oil temperature of the air compressor is detected to be less than the first temperature preset value, the contact K1+ and contact K1- of the analog quantity to switch quantity relay U5 are disconnected, and the coil of the relay K7 is powered through the self-locking circuit, and the DC fan remains in the working state; S10, when the lubricating oil temperature of the air compressor is detected to be less than the second temperature preset value, the contact K2+ and contact K2- of the analog quantity to switch quantity relay U5 are closed, the coil of the relay K8 is powered, the contact 11 and contact 12 of the relay K8 are disconnected, the coil of the relay K7 is de-energized, the contact 13, contact 14, contact 15, and contact 16 of the relay K7 are disconnected, and the DC fan stops working;

[0083] S11. When the lubricating oil temperature of the air compressor is detected to be greater than the protection temperature threshold, the coil of relay K4 is energized, contacts 11 and 12 of relay K4 are disconnected, the coil of relay K2 is de-energized, and the air compressor stops working.

[0084] Although the present invention has been described above with preferred embodiments, it is not intended to limit the present invention. A person skilled in the art of the present invention may make various modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the definition of the claims.

Claims

1. A control circuit for an air compressor of a suspended monorail vehicle, characterized in that: include: A temperature detection module and an air compressor cooling fan start / stop circuit connected to the temperature detection module; The temperature detection module includes: a temperature transmitter U3, and a signal isolator U4 connected to the temperature transmitter U3; the temperature transmitter U3 is used to detect the lubricating oil temperature of the air compressor M1, and convert the oil temperature signal into a current signal, the signal isolator U4 receives the current signal output by the temperature transmitter U3, and converts it into two equal current signals, and outputs one of the current signals to the start and stop circuit of the air compressor cooling fan; The air compressor cooling fan start-stop circuit includes: analog quantity conversion switch quantity relay U5, relay K7, relay K8, and DC fan; The analog quantity conversion switch relay U5 is connected to the signal isolator U4, and receives one of the current signals output from the signal isolator U4. The analog quantity conversion switch relay U5 is connected to relay K7 and relay K8 respectively. When the lubricating oil temperature of the air compressor M1 is greater than the first temperature preset value, the relay K7 coil is energized, and the DC fan M2 is energized and started; when the lubricating oil temperature of the air compressor M1 is lower than the second temperature preset value, the relay K8 coil is energized, and the DC fan M2 loses power and stops working.

2. The air compressor control circuit of a suspended monorail vehicle according to claim 1, characterized in that: It also includes an air compressor start-stop circuit connected to the temperature detection module. The air compressor start-stop circuit includes: analog quantity conversion switch relay U2, pressure switch U1, contactor K1, relay K2, relay K3, relay K4, delay relay K5, diode V1, air compressor M1, pump air circuit breaker F1; The port IN+ and the port GND of the analog conversion switch relay U2 are connected to the 9th and 10th points of the signal isolator U4 respectively. The analog conversion switch relay U2 receives another current signal output from the signal isolator U4. The three sets of main contacts of the contactor K1 are connected to the AC 380V external power supply and the air compressor M1 respectively. The contact 2 of the pump air circuit breaker F1 is connected to the positive pole of the DC 24V external power supply. The contact 1 of the pump air circuit breaker F1 is connected to the contact 14 of the relay K2. When the contacts 13 and 14 of the relay K2 are closed, the coil of the contactor K1 is energized, the main contacts of the contactor K1 are closed, and the air compressor M1 is started. Point 1 of the pressure switch U1 is connected to the positive pole of the DC 24V external power supply, and point 2 of the pressure switch U1 is connected to the positive pole of the diode V1; the negative pole of the diode V1 is connected to the contact 12 of the relay K4; The normally closed contacts of relay K4 and time delay relay K5 are connected to the A1 point of relay K2, the A1 point of time delay relay K5 is connected to the A2 point of relay K4, the contact 11 of relay K4 is connected to the contact 16 of time delay relay K5, the contact 15 of time delay relay K5 is connected to the A1 end of the coil of relay K2, and the A2 end of relay K2 is connected to the negative pole of the DC24V external power supply; when the pressure switch U1 detects that the brake line pressure is lower than the first pressure preset value, the point 1 and the point 2 of the pressure switch U1 are connected, the coil of relay K2 is energized, the contacts 13 and 14 of relay K2 are closed, the coil of contactor K1 is energized, the main contacts of contactor K1 are closed, and the air compressor M1 is started; Relay K3 is connected to the DC 24V external power supply and point 2 of the pressure switch U1 respectively; when the pressure switch U1 detects that the pressure is higher than the second pressure preset value, point 1 and point 2 of the pressure switch U1 are disconnected, the coil of relay K3 loses power, contacts 11 and 12 of relay K3 are closed, contact K1+ of the analog conversion switch relay U2 is connected to contact 11 of relay K3, and contact 12 of relay K3 is connected to the positive pole of the DC 24V external power supply; contact K1- of the analog conversion switch relay U2 is connected to point A3 of the delay relay K5; when the air compressor lubricating oil temperature is higher than the third temperature preset value, contact K1 of the analog conversion switch relay U2 is closed, the coil of the delay relay K5 is energized, and after a preset time, contacts 15 and 16 of the delay relay K5 are disconnected, the coil of relay K2 loses power, contacts 13 and 14 of relay K2 are disconnected, the coil of contactor K1 loses power, and the air compressor M1 stops working; The A1 point of relay K4 is connected to the contact K2- of the analog quantity conversion switch relay U2, and the A2 point of relay K4 is connected to the negative pole of the DC 24V external power supply. When the oil temperature is greater than the protection temperature threshold, the contacts K2+ and K2- of the analog quantity conversion switch relay U2 are closed, and the A1 point of relay K4 is connected to the contact K2- of the analog quantity conversion switch relay U2, and the K2+ contact is connected to the positive pole of the DC 24V external power supply. The coil of relay K4 is energized, contacts 11 and 12 of relay K4 are disconnected, the coil of relay K2 is de-energized, contacts 13 and 14 of relay K2 are disconnected, the coil of contactor K1 is de-energized, and the air compressor M1 stops working.

3. The air compressor control circuit of a suspended monorail vehicle according to claim 1, characterized in that: The specific circuit for starting and stopping the cooling fan of the air compressor is as follows: the 11th and 12th points of the signal isolator U4 are connected to the port IN+ and the port GND of the analog conversion switch relay U5 respectively; The contact K1+ of the analog quantity conversion switch relay U5 is connected to the positive pole of the DC 24V external power supply, and the contact K1- is connected to the A2 point of the relay K7. When the lubricating oil temperature of the air compressor is greater than the first temperature preset value, the contact K1+ and the contact K1- are closed, that is, the contact K1+ and the contact K1- are connected, the relay K7 coil is energized, the contact 15 and the contact 16 of the relay K7 are closed, the DC fan M2 is powered by DC24V, and the fan starts to work; The contact K2+ of the analog quantity conversion switch relay U5 is connected to the positive pole of the DC 24V external power supply, the contact K2- is connected to the A1 point of the relay K8, and the A2 point of the relay K8 is connected to the negative pole of the DC 24V external power supply. When the lubricating oil temperature of the air compressor M1 is lower than the second temperature preset value, the contact K2+ and the contact K2- are closed, that is, the contact K2+ and the contact K2- are connected, the coil of the relay K8 is energized, the contacts 11 and 12 of the relay K8 are disconnected, the coil of the relay K7 is de-energized, the contacts 15 and 16 of the relay K7 are disconnected, the DC fan M2 loses the DC24V power, and the DC fan M2 stops working.

4. A control circuit for an air compressor of a suspended monorail vehicle according to claim 2, characterized in that , also includes a strong pump air switch S1, which manually starts the DC fan M2 through the pump air circuit breaker F1 and the forced pump air button S. Specifically, the contact 1 of the pump air circuit breaker F1 is connected to the contact 13 of the forced pump air button S and the contact 14 of the relay K2, and the contact 14 of the forced pump air button S is connected to the A1 point of the contactor K1 and the contact 13 of the relay K2.

5. The control circuit of the suspended monorail vehicle air compressor M1 according to claim 1, characterized in that: The first temperature preset value is 95°C, the second temperature preset value is 90°C, the third temperature preset value is 80°C, and the protection temperature threshold is 100°C.

6. The air compressor control method based on the air compressor control circuit of the suspended monorail vehicle according to claim 4, characterized in that: Also includes: Start the forced pump air button S to energize the three-phase contactor K1 coil of the air compressor, forcing the air compressor M1 to work.

7. The air compressor control method based on the air compressor control circuit of the suspended monorail vehicle according to claim 2, characterized in that: When point 1 and point 2 of the pressure switch U1 are connected and the coil of the relay K2 is energized, the contacts 17 and 18 of the relay K2 are closed, and the coil of the relay K2 is kept energized through the contacts 17 and 18.

8. An air compressor control method based on a suspended monorail vehicle air compressor control circuit, characterized in that: The method comprises the following steps: S1, the pressure switch U1 detects the air pressure of the brake pipeline. When the air pressure of the brake pipeline is lower than the first preset air pressure value, the first point position and the second point position of the pressure switch U1 are connected, the coil of the relay K2 is energized, the 24V coil of the contactor K1 is energized, the three-phase contacts of the contactor K1 are closed, and the air compressor M1 starts to work; S2. After the air compressor M1 starts working, the air pressure in the brake system air circuit increases. When the pressure switch U1 detects that the air pressure is greater than the second preset air pressure value, the first point position and the second point position of the pressure switch U1 are disconnected, and the normally closed contact of the relay K3 is closed; S3, the temperature transmitter U3 detects the lubricating oil temperature of the air compressor, converts the oil temperature signal into a current signal, and outputs the current signal to the signal isolator U4. The signal isolator U4 receives the current signal output by the temperature transmitter U3, and converts the current signal into two equal current signals LS1 and LS2; S4, the signal isolator U4 outputs the current signal LS1 to the analog quantity to switch quantity relay U2, and outputs the current signal LS2 to the analog quantity to switch quantity relay U5; S5. According to the relationship between temperature and current defined by the temperature transmitter U3, the current threshold corresponding to the third temperature preset value and the protection temperature threshold is set in the analog quantity to switch quantity relay U2, and the current threshold corresponding to the first temperature preset value and the second temperature preset value is set in the analog quantity to switch quantity relay U5; S6, when the lubricating oil temperature of the air compressor is detected to be greater than the third temperature preset value, the contact K1+ and contact K1- of the analog quantity to switch quantity relay U2 are closed, and the coil of the delay relay K5 is energized; S7, set the delay time of the delay relay K5. When the delay relay K5 coil is energized beyond the preset value, the normally closed contacts 15 and 16 of the delay relay K5 are disconnected, the relay K2 coil loses power, the relay K2 contacts 13 and 14 are disconnected, and the air compressor stops working; S8, when the lubricating oil temperature of the air compressor is detected to be greater than the first temperature preset value, the contact K1+ and contact K1- of the analog switch relay U5 are closed, the coil of the relay K7 is energized, the contact 15 and contact 16 of the relay K7 are closed, the DC fan is energized to work, and the air compressor is cooled; at the same time, the contact 13 and contact 14 of the relay K7 are closed, forming a self-locking circuit to power the coil of the relay K7; S9, when the lubricating oil temperature of the air compressor is detected to be lower than the first temperature preset value, the contact K1+ and the contact K1- of the analog quantity to switch quantity relay U5 are disconnected, and the coil of the relay K7 is powered through the self-locking circuit, and the DC fan remains in working state; S10, when the lubricating oil temperature of the air compressor is detected to be lower than the second temperature preset value, the contact K2+ and the contact K2- of the analog switch relay U5 are closed, the coil of the relay K8 is energized, the contact 11 and the contact 12 of the relay K8 are disconnected, the coil of the relay K7 is de-energized, the contact 13, the contact 14, the contact 15 and the contact 16 of the relay K7 are disconnected, and the DC fan stops working; S11. When the lubricating oil temperature of the air compressor is detected to be greater than the protection temperature threshold, the coil of relay K4 is energized, contacts 11 and 12 of relay K4 are disconnected, the coil of relay K2 is de-energized, and the air compressor stops working.

9. The air compressor control method based on the air compressor control circuit of the suspended monorail vehicle according to claim 8, characterized in that: In step S5, the relationship between temperature and current is as follows: the output current signal corresponding to the temperature range of -50 to 200° C. is 4 to 20 mA.

10. The air compressor control method based on the air compressor control circuit of the suspended monorail vehicle according to claim 8, characterized in that: The first air pressure preset value is 8.5 bar, and the second air pressure preset value is 9.5 bar.

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