CN201078454Y - Wheeled engineering machinery friction slice type electric nonskid differential system - Google Patents

Abstract

The utility model discloses a wheeled model engineering mechanical friction disc type electronic anti-slip differential speed system. An electromagnetic valve, an accumulator and a main control circuit module are arranged on a traditional friction disc automatic anti-slip differential speed system; wherein, the electromagnetic valve and the accumulator are mounted on a plurality of clutch plated at an output end of the traditional differential speed system. The command pressure of the system is from the electromagnetic valve, an accumulator and a main control circuit module of the accumulator. The main control circuit module comprises an electric control unit, a wheel speed identification unit, an electromagnetic valve control unit, a system protection unit and a pressure detecting unit. The electric control unit is taken as a core of the utility model, handling the sensor signals and regulating the value of the command pressure through controlling the switching of the electromagnetic valve. The system provides a relatively large variable differential speed range and optimal driving force to maintain the directional stability of the vehicles and reduce the tire abrasion as well as decrease the engine power consumption.

Description

Friction plate type electronic anti-skid differential system for wheeled construction machinery

technical field

The utility model relates to an electronic automatic anti-slip differential system of a wheeled construction machine, which further includes an electromagnetic valve, an energy accumulator and a main control circuit module on the basis of the traditional friction plate automatic anti-slip differential system.

Background technique

With the needs of people's travel and transportation, the requirements for the performance of engineering vehicles are getting higher and higher, so the application of anti-skid differential systems is becoming more and more extensive. In terms of form, three types of non-slip differentials, torque sensing, speed sensing, and active control, are used. The anti-skid differential system can not only improve the passability of engineering vehicles on bad roads, but also greatly improve the safety, handling stability and ride comfort of the vehicle.

The application and development of the anti-skid differential system in foreign countries is relatively early. At present, the TCS system with brake anti-lock and drive anti-skid functions has developed into an electronic control system with multiple functions, managed by a microprocessor, and controlled by sensors and actuators. system.

Compared with foreign countries, domestic anti-skid differential system research started relatively late, and no independent products have come out yet. Domestic research on traction control systems is still in its infancy, and practical research on ABS hardware and software systems is still in its infancy. Jinan Heavy Duty Truck Group, Jilin University, Military Transportation Research Institute of the General Logistics Department, Tongji University and other units have conducted research on this topic, and most of the research has focused on control logic, and mature product technology has not yet been formed.

The current mainstream limited slip differentials include positive locking differentials, high friction self-locking differentials, jaw freewheel differentials, worm gear differentials, and viscous coupling differentials. Each has its own advantages and fields of application, but all have disadvantages and deficiencies to varying degrees. If it is difficult to grasp the operation of the forced locking differential, the vehicle must be stopped before locking the differential. High-friction self-locking differentials can withstand relatively small torques and cannot transmit large torques, so high-friction self-locking differentials are not suitable for heavy-duty vehicles. Jaw-type freewheel differentials are mostly used on medium and heavy wheels, but the torque transmission of the left and right wheels is intermittent, causing uneven loads in the transmission. The worm gear differential has an automatic locking effect when the torque difference is large, which hinders the normal differential action, and is usually not used as an inter-wheel differential for the steering drive shaft; in addition, because it cannot transmit too much torque, it is therefore Applications on heavy vehicles are limited. The viscous coupling non-slip differential utilizes the resistance torque of the liquid to limit the differential speed, improves the torque distribution of the non-slip driving wheels, thereby improving the cross-country passability of the vehicle, and is mostly used in light vehicles.

In the utility model patent CN2039771 automatic anti-slip differential for automobiles and wheeled tractors announced on June 21, 1989, a friction-type automatic anti-slip differential suitable for automobiles and wheeled tractors is disclosed. It consists of an ordinary symmetrical bevel gear differential and a lock-up brake including brake friction plates (discs), which can automatically perform differential speed and lock-up according to the adhesion between the driving wheel and the ground. In the invention patent application CN1064244A vehicle high-efficiency energy-saving automatic anti-skid differential system published on September 9, 1992, a high-efficiency energy-saving automatic anti-skid differential system suitable for all motor vehicles at home and abroad was proposed. It consists of a speed reducer, an electromagnetic controller for forced engagement, and a random device for automatically shutting down the engine. It effectively solves the problems that the differential speed and anti-slip of the gear-type locking differential cannot be used together, the parking operation is required, the power loss is enhanced, and the inertia energy of the vehicle is wasted during driving.

Although the above two systems have realized the functions of automatic differential and anti-skid, the locking range of the differential system is small, the traction maneuverability is poor, and the working environment of construction machinery is harsh, so there are still some problems in the specific operation in practice. Some deficiencies. It is necessary to further improve it.

Utility model content

The technical problem to be solved by the utility model is to propose an electronically controlled hydraulically operated variable locking differential system, which increases the locking range and controls the difference in the slip rates of the left and right driving wheels within the allowable range. By locking the differential, the driving force of the driving wheel on the high adhesion coefficient side can be fully exerted to improve vehicle speed and driving stability; at the same time, the control of the degree of differential locking can increase the driving stability and maneuverability in curves.

In order to solve the above-mentioned technical problems, the technical proposal of the present utility model is: a wheeled construction machinery friction plate electronic anti-skid differential system, including a symmetrical bevel gear differential 6 and a lock-up brake with friction plates, and also includes an electromagnetic Valve 7, accumulator 8 and main control circuit module;

-The solenoid valve 7 and the accumulator 8 are installed on the multi-disc clutch plate at the output end of the symmetrical bevel gear differential 6, and the pressure provided by the accumulator 8 is adjusted by controlling the on-off of the solenoid valve 7;

-The main control circuit module includes an electronic control unit 1, a wheel speed identification unit 2, a solenoid valve control unit 3, a system protection unit 4 and a pressure detection unit 5, the wheel speed identification unit 2 is connected to the electronic control unit 1, and the wheel speed identification unit 2 The wheel speed sensor of the wheel speed sensor transmits the sampling signal to the electronic control unit 1; the electronic control unit 1 is connected to the solenoid valve control unit 3 at the same time, and the solenoid valve control unit 3 controls the on-off of the solenoid valve 7; the solenoid valve control unit 3 is connected to the pressure detection unit 5 to It transmits a control signal, and the pressure detection unit 5 detects the pressure provided by the accumulator 8 ; the electronic control unit 1 is connected with the protection unit 4 .

As a preferred solution of the present invention, the electronic control unit 1 uses an AT89C4051 single-chip microcomputer as the core, processes the sampling signal from the wheel speed identification unit 2, and controls the on-off of the solenoid valve 7 through the solenoid valve control unit 3 .

As another preferred solution of the present utility model, the wheel speed sensor is an Omron EE-SX670-4 photoelectric sensor.

As another preferred solution of the present utility model, the wheel speed sensor transmits signals to the electronic control unit 1 through the 8050 circuit, the optocoupler circuit and the inverter 74LS14.

As a further preferred solution of the present invention, the solenoid valve control unit 3 controls the on-off of the solenoid valve 7 through the optocoupler circuit, the inverter 74HS14 and the relays K1 and K2.

As another preferred solution of the present utility model, the pressure detection unit 5 includes a pressure measurement circuit and a pressure identification circuit, the pressure measurement circuit uses the HT46R71D chip as the main chip, and the pressure sensor in the pressure identification circuit and the HT46R71D chip in the pressure measurement circuit Connection, the HT46R71D chip in the pressure measurement circuit is connected with the LCD display.

The working principle of the system is: two wheel speed sensors detect the wheel speeds of the two driving wheels, compare the best slip ratios, and then control the corresponding action of the solenoid valve. The electronic control unit adjusts the control pressure value through the solenoid valve, and the variable control pressure provided by the accumulator hydraulic pressure controls the corresponding action of the friction plate to change the friction coefficient; the signal generated by the driving wheel speed sensor is fed back to the electronic control unit to implement feedback control. This way the degree of locking can be varied gradually. The electronically controlled differential system can control the slip ratio of the left and right drive wheels or the front and rear drive axles within the allowable range. When the vehicle starts, adjust the locking degree of the differential to make full use of the driving force and improve the speed and driving stability; when the left and right driving wheels are driving on roads with different separation adhesion coefficients and curves, it can improve the stability of the vehicle Sexual driving ability.

Since the utility model installs electromagnetic valves and accumulators on the multi-disc clutch discs at the output end of the traditional differential system, the pressure sensor is used to realize the control of increasing and decreasing pressure. This method can make the degree of locking change gradually. It is an electronically controlled hydraulically operated variable locking differential system, and its control pressure comes from the high pressure oil of the accumulator. The electronic control unit adjusts the size of the control pressure value by controlling the solenoid valve. Through the electronically controlled differential system, the slip ratio of the left and right drive wheels or the front and rear drive axles can be controlled within the allowable range.

When the vehicle starts, adjust the locking degree of the differential to make full use of the driving force and improve the speed and driving stability; when the left and right driving wheels are driving on roads with different separation adhesion coefficients and curves, it can improve the stability of the vehicle Sexual driving ability. At the same time, it reduces tire wear and engine power consumption, making driving safer and easier to operate.

At the same time, there is no obvious difference between the handling characteristics and the ordinary differential, and the driver does not need to be familiar with the new limited-slip drive system to operate it skillfully.

Description of drawings

Below in conjunction with accompanying drawing and specific embodiment, the utility model is described in further detail.

Fig. 1 is a schematic diagram of the system structure of the utility model.

Fig. 2 is a circuit block diagram of the main control circuit module of the utility model.

FIG. 3 is a schematic circuit diagram of the electric control unit 1 and the system protection unit 4 of the present invention.

FIG. 4 is a schematic circuit diagram of the wheel speed identification unit 2 of the present invention.

Fig. 5 is a schematic circuit diagram of the solenoid valve control unit 3 of the present invention.

Fig. 6 is a structural schematic diagram of the pressure sensor of the present invention.

Fig. 7 is a schematic diagram of the signal power amplification circuit of the pressure sensor of the present invention.

Fig. 8 is a schematic circuit diagram of the pressure detection unit of the present invention.

Detailed ways

With reference to Fig. 1 and Fig. 2, the friction plate type electronic anti-skid differential system of wheeled construction machinery includes a symmetrical bevel gear differential 6 and a lock-up brake with friction plates, and also includes a solenoid valve 7 and an accumulator 8 And the main control circuit module; wherein the solenoid valve 7 and the accumulator 8 are installed on the multi-disc clutch plates at the output end of the symmetrical bevel gear differential 6, and the pressure provided by the accumulator 8 is adjusted by controlling the on-off of the solenoid valve 7; The main control circuit module includes an electronic control unit 1, a wheel speed identification unit 2, a solenoid valve control unit 3, a system protection unit 4 and a pressure detection unit 5, the wheel speed identification unit 2 is connected to the electronic control unit 1, and the wheel speed identification unit 2 The wheel speed sensor of the wheel speed sensor transmits the sampling signal to the electronic control unit 1; the electronic control unit 1 is connected to the solenoid valve control unit 3 at the same time, and the solenoid valve control unit 3 controls the on-off of the solenoid valve 7; the solenoid valve control unit 3 is connected to the pressure detection unit 5 to It transmits a control signal, and the pressure detection unit 5 detects the pressure provided by the accumulator 8 ; the electronic control unit 1 is connected with the protection unit 4 .

Among them, the electronic control unit 1 is used to process the wheel speed sensor signal and control the on-off of the solenoid valve; the wheel speed identification unit 2 transmits the wheel speed sensor signal to the electronic control unit 1; the solenoid valve control unit 3 realizes the on-off control of the solenoid valve; The system protection unit 4 provides a protection function when the system fails; the pressure detection unit 5 also includes a pressure measurement circuit and a pressure identification circuit, and adjusts and controls the pressure value through the solenoid valve 7, so that the pressure value is controlled within a certain variable range Inside. The variable control pressure provided by the hydraulic pressure of the accumulator 8 controls the corresponding action of the friction plate and changes the friction coefficient; when the adhesion coefficient of the wheels on both sides of the road surface is different, the friction coefficient of the friction plate must be changed to a certain extent.

As shown in FIG. 3 , the electronic control unit 1 is the core of the entire main control circuit. In this preferred mode, an AT89C4051 single-chip microcomputer (MCU) is used to process sensor signals and control the on-off of the solenoid valve 7 . AT89C4051 chip address allocation and connection of related pins are P3.4, P3.5 pins connected to the signal output terminal of wheel speed identification unit 2 to process the signal collected by the wheel speed sensor; P1.6, P1.7 pins connected to The solenoid valve control unit 3 adjusts the size of the control pressure plant by controlling the on-off of the solenoid valve; the P1.0-P1.3 pins are sequentially connected to the 4 input pins of the X25045 watchdog circuit, and the RST output of the X25045 The pin is connected to the RST input terminal of the AT89C4051 chip and connected to the power supply terminal of the AT89C4051 chip through the pull-up resistor R11.

X25045 is a programmable circuit that integrates three functions of watchdog, voltage monitoring and serial EPROM. This combination design reduces the circuit's need for board space. The watchdog in X25045 has provided the protection function to the system. When the system breaks down and exceeds the set time, the watchdog in the circuit will respond to the MCU through the RESET signal. X25045 provides three time values for users to choose. It also has a voltage monitoring function that protects the system from low voltage. When the power supply voltage drops below the allowable range, the system will reset until the power supply voltage returns to a stable value. The memory of X25045 and MCU can be interfaced through serial communication, with a total of 4096 bits, and data can be placed in 512×8 bytes.

As shown in Figure 4, in this preferred mode, the wheel speed sensor adopts the Omron EE-SX670-4 photoelectric sensor, and the photoelectric element is used as the detection element. First, the measured change is converted into a signal change, and then further Convert optical signals into electrical signals. As shown in Figure 3, the photoelectric sensor transmits the induced left and right wheel-related electrical signals (high and low level change pulses) to the single-chip microcomputer AT89C4051 through the CN_IN access terminal pin 5 and pin 2. For pin 5: when it is high level, it is applied to the base of the triode Q2 after being divided by the resistor R3. At this time, the triode Q2 is turned on, and the voltage on the collector is only a tube voltage drop. In this way, the level of the optocoupler circuit is pulled low and then turned on, so that the input level of the inverter U1B is pulled high, and after inversion, the low level is transmitted to the P3.4 interface of the single-chip AT89C4051. When the sensor transmits a low level, the triode Q2 is not turned on, and the optocoupler cannot work. The input level of the inverter U1B is low level, and after the inversion, the high level is transmitted to P3 of the microcontroller AT89C4051. 4 interfaces. In summary, the high-low level conversion generated by the sensor forms a pulse, and the pulse is counted per unit time to obtain the wheel speed. The connection function between pin 2 and P3.5 interface is the same as that of pin 5 and P3.4 interface.

It can be seen from Figure 5 that the P1.6 and P1.7 pins of the AT89C4051 single-chip microcomputer, namely the MCU, are connected to the input end of the solenoid valve control unit 3 . In this preferred mode, the switching signal output by the bidirectional I/O port P1.6 pin of the MCU is reversed by U1F and then connected to the input port IN2 of U92003 to improve its driving capability, and then the signal is transmitted to the relay through the output port OUT1 of U9 K1. At the same time, in order to facilitate the adjustment of the circuit, a dial switch U10 is added, and its interfaces 8 and 6 are respectively connected to the input ports IN1 and IN4 of U92003. In the relay driving part, in order to prevent the strong magnetic field generated when the relay is turned on and off, a freewheeling diode D14 is added to the voltage and current for circuit protection. At the same time, at the relay contact, because the high voltage is passed through, the on-off of the contact is easy to cause a crash, so a resistance-capacitance absorption circuit is added to the output part. When P1.6=0, the relay acts to open the solenoid valve, otherwise, when P1.6=1, the solenoid valve closes. Pin P1.7 controls the on-off mode of the solenoid valve with the same pin P1.6.

The pressure detection unit 5 includes a pressure measurement circuit and a pressure identification circuit. The pressure measurement circuit uses the HT46R71D chip as the main chip. The pressure sensor in the pressure identification circuit is connected to the HT46R71D chip in the pressure measurement circuit. The HT46R71D chip in the pressure measurement circuit is connected to the LCD connect. As shown in Figure 6, in this preferred solution, the YX-PS-B series pressure sensor with a full-scale (100PSI) output of 60mV under a 3.3V working voltage is selected, with a total of four pins, and pins 02 and 04 are the positive and negative power supply. Negative terminal, pin 01 is connected to the VA terminal of the power amplifier circuit, and pin 03 is connected to the VB terminal of the power amplifier circuit. Among them, the sensor is a silicon piezoresistive pressure sensor. A pressure-sensitive elastic film is manufactured on single crystal silicon through anisotropic etching technology, and four pressure-sensitive resistors are manufactured by semiconductor processing, which consists of pins DOPAP, DOPAN, DOPAO, and DCHOP. Wheatstone bridge to detect changes in applied pressure. As shown in Figure 7, after the signal generated by the pressure sensor passes through the power amplifier circuit, the four pins DOPAP, DOPAN, DOPAO, and DCHOP of the sensor are respectively connected to the four pins DOPAP, DOPAN, DOPAO, and DOPAP of the microcontroller HT46R71D of the sensor in sequence. DCHOP, transmit the sensed pressure signal to the main chip.

As shown in Figure 8, the main chip HT46R71D is a dual-integral analog/digital conversion single-chip microcomputer, which contains an amplifier, a voltage follower, an integrator and a comparator. When charging, the internal multi-way switch is switched to the output of the amplifier, and the charging and discharging capacitor Vc is charged through the integration circuit; when discharging, the multi-way switch is switched to VDSO, and Vc starts to discharge. When its voltage drops to 1/6VDSO, the comparator That is, output low level, which is regarded as the end of discharge. The VOBGP pin of the single-chip microcomputer HT46R71D of the sensor is connected to the pin 4 of the sensor to provide a positive voltage for the sensor; the SEG0-SEG8 pins of the chip HT46R71D are sequentially connected to the SEG0-SEG8 pins of the LCD display to transmit the detected pressure value signal to LCD monitor and display it.

Claims (6)

1. A wheeled construction machinery friction disc type electronic anti-skid differential system, comprising a symmetrical bevel gear differential (6) and a lock-up brake with friction discs, is characterized in that: it also includes a solenoid valve (7), Accumulator (8) and main control circuit module; -The solenoid valve (7) and the accumulator (8) are installed on the multi-disc clutch plate at the output end of the symmetrical bevel gear differential (6), and the accumulator (8) is adjusted by controlling the on-off of the solenoid valve (7) the amount of pressure provided; -The main control circuit module includes an electronic control unit (1), a wheel speed identification unit (2), a solenoid valve control unit (3), a system protection unit (4), a pressure detection unit (5), and a wheel speed identification unit (2) Connected to the electronic control unit (1), the wheel speed sensor in the wheel speed identification unit (2) transmits sampling signals to the electronic control unit (1); the electronic control unit (1) is connected to the solenoid valve control unit (3) at the same time, and the solenoid valve controls The unit (3) controls the on-off of the solenoid valve (7); the solenoid valve control unit (3) is connected to the pressure detection unit (5), and transmits a control signal to it, and the pressure detection unit (5) provides energy to the accumulator (8) The pressure is detected; the electric control unit (1) is connected with the protection unit (4). 2. The friction disc type electronic anti-skid differential system for wheeled construction machinery according to claim 1, characterized in that: the electronic control unit (1) uses the AT89C4051 single-chip microcomputer as the core to process the information from the wheel speed identification unit (2) The signal is sampled, and at the same time, the on-off of the solenoid valve (7) is controlled by the solenoid valve control unit (3). 3. The friction plate type electronic anti-skid differential system of wheel construction machinery according to claim 1 or 2, characterized in that: the wheel speed sensor is an Omron EE-SX670-4 photoelectric sensor. 4. The friction plate type electronic anti-skid differential system for wheeled construction machinery according to claim 3, characterized in that: the wheel speed sensor communicates to the electronic control unit (1) through the 8050 circuit, the optocoupler circuit and the inverter 74LS14 transmit signal. 5. The friction plate type electronic anti-skid differential system of wheeled construction machinery according to claim 1 or 2, characterized in that: the solenoid valve control unit (3) passes through the optocoupler circuit, the inverter 74HS14 and the relay K1, K2 controls the on-off of the solenoid valve (7). 6. The friction plate type electronic anti-skid differential system of wheeled construction machinery according to claim 1 or 2, characterized in that: the pressure detection unit (5) includes a pressure measurement circuit and a pressure identification circuit, and the pressure measurement circuit is HT46R71D The chip is the main chip, the pressure sensor in the pressure recognition circuit is connected with the HT46R71D chip in the pressure measurement circuit, and the HT46R71D chip in the pressure measurement circuit is connected with the LCD display.

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