CN203439027U - Hydraulic auxiliary drive and brake system - Google Patents

Abstract

The utility model discloses a hydraulic auxiliary driving and braking system, which solves the problems of poor passability of existing commercial trucks on bad roads and unstable braking during long-term driving braking. box, rear drive axle, two front wheels, accelerator pedal, brake pedal, frame, power take-off, axial swash plate type high-pressure variable pump, three-position four-way electromagnetic reversing valve, electro-hydraulic proportional relief valve, Heat exchanger, safety valve group, two hydraulic quantitative motors with the same structure, oil tank and electronic control unit, among them, the axial swash plate type high-pressure variable pump is connected with the three-position four-way electromagnetic reversing valve pipeline, and the three-position four-way The electromagnetic reversing valve is respectively connected with the safety valve group, the electro-hydraulic proportional overflow valve and the oil tank pipeline, and the two hydraulic quantitative motors with the same structure are connected with the pipeline of the axial swash plate type high-pressure variable pump.

Description

A hydraulic auxiliary driving and braking system

technical field

The utility model relates to a driving and braking device belonging to the technical field of automobile hydraulic application, more specifically, the utility model relates to a hydraulic auxiliary driving and braking system.

Background technique

In recent years, with the rapid development of the automobile industry in the 21st century, a major breakthrough has been made in the application of secondary regulation hydrostatic transmission technology in traditional vehicles. This technology has gradually attracted great attention from domestic and foreign research institutions and automobile manufacturers. In China, research on the application of hydraulic technology in automobiles is mainly concentrated in colleges and universities, and related hydraulic drive technology is mostly used in energy-saving and environmentally friendly oil-hydraulic power coupling systems, including parallel and hybrid hydraulic drive hybrid systems, etc. Hydraulic braking technology The application is also mostly limited to the research on the hydraulic actuator structure during braking. Abroad, Eaton Corporation of the United States applies hydraulic drive technology to various types of vehicles such as cars and urban buses; Mitsubishi Corporation of Japan and M.A.N Corporation of Germany apply hydraulic energy storage systems to urban buses, and have developed multiple systems in Europe and North America. city use.

The working conditions of traditional commercial trucks, large trucks, tractors and engineering vehicles are mostly rural bad roads or mine roads, and long slope roads. These roads have large unevenness and generally small adhesion coefficients. The phenomenon of driving wheel slipping often occurs, which affects the power and passability of the vehicle. At the same time, the vehicle often encounters downhill and long-term driving braking conditions, which requires continuous or frequent use of the driving brakes, resulting in damage to the brake drum and brake pads. Severe wear makes the braking system easy to lose control, which not only reduces the service life of the service brake, but also seriously affects the driving safety.

Although the hydraulic hybrid coupling system partially improves the power and braking performance of traditional vehicles, its main function is to save energy, and the structure changes greatly, the control algorithm is complicated, and the cost is high. It is not suitable for traditional trucks and heavy trucks. The hydraulic retarder proposed by Xiangtan University and other institutions can improve the braking performance of the vehicle, but it does not improve the power and passability of the vehicle when driving on bad roads.

Contents of the invention

The technical problem to be solved by the utility model is to overcome the problems of poor passability of commercial trucks on bad roads and unstable braking during long-term driving, and propose a set of A hydraulically assisted driving and braking system that can simultaneously improve vehicle passability and braking stability.

In order to solve the above-mentioned technical problems, the utility model adopts the following technical solutions to realize, in conjunction with the accompanying drawings:

The utility model provides a hydraulic auxiliary driving and braking system, which includes an engine 1, a clutch 2, a gearbox 4, a rear drive axle 5, two rear wheels 6, two front wheels 7, an accelerator pedal 18, and a brake pedal 19 and the vehicle frame, the crankshaft output shaft 16 of the engine 1 is connected with the input shaft of the clutch 2 by a spline pair, the output shaft of the clutch 2 is connected with the input shaft of the gearbox 4 by a spline pair, and the output shaft of the gearbox 4 is connected with the rear The input shaft of the drive axle 5 is connected by a spline pair; it also includes a power take-off 3, an axial swash plate type high-pressure variable pump 9, a three-position four-way electromagnetic reversing valve 10, an electro-hydraulic proportional overflow valve 11, and a heat exchanger 12. The safety valve group 14, two hydraulic quantitative motors 15 with the same structure, the oil tank 13 and the electronic control unit 8, wherein the input shaft of the power take-off 3 and the output shaft 17 of the engine 1 drive accessories are connected by a spline pair, The output shaft of the power take-off 3 is connected to the rotor shaft of the axial swash plate type high-pressure variable pump 9 through a flange; The four-way electromagnetic reversing valve 10 is respectively connected to the safety valve group 14, the electro-hydraulic proportional relief valve 11, and the oil tank 13; the oil outlet of the safety valve group 14 is connected to the oil inlet ports of two hydraulic quantitative motors 15 with the same structure Pipeline connection, the oil outlets of two hydraulic quantitative motors 15 with the same structure are connected with the oil inlet pipeline of the axial swash plate type high-pressure variable pump 9; the oil outlet of the electro-hydraulic proportional relief valve 11 is connected with the heat exchanger The oil inlet of 12 is connected to the pipeline, and the oil outlet of the heat exchanger 12 is connected to the pipeline of the oil tank 13; the electronic control unit 8 is respectively connected to the engine 1, the axial swash plate type high-pressure variable pump 9, and the three-position four-way electromagnetic pump through the signal line. The reversing valve 10, the electro-hydraulic proportional relief valve 11, the accelerator pedal 18 and the brake pedal 19 are connected.

According to a hydraulic auxiliary driving and braking system provided by the utility model, the oil outlet of the axial swash plate type high-pressure variable pump 9 and the P port of the three-position four-way electromagnetic reversing valve 10 are sealed and connected through a high-pressure oil pipeline , the A port of the three-position four-way electromagnetic reversing valve 10 is sealed with the oil inlet port of the safety valve group 14 through a high-pressure oil pipeline, and the B port of the three-position four-way electromagnetic reversing valve 10 is connected to the electro-hydraulic proportional overflow valve 11 The oil inlet is sealed and connected through a high-pressure oil pipeline, and the T port of the three-position four-way electromagnetic reversing valve 10 is sealed and connected with the oil tank 13 through a low-pressure oil pipeline; position, realize the different connecting positions of P port and A port, B port, T port, and control the oil outlet of the axial swash plate type high-pressure variable pump 9 to connect to different hydraulic circuits.

According to a hydraulic auxiliary driving and braking system provided by the utility model, two hydraulic quantitative motors 15 with the same structure are sequentially installed on the hubs of the two front wheels 7, and the axial swash plate type high-pressure variable pump 9 is fixed on the vehicle. on the frame; the oil outlet of the safety valve group 14 is sealed and connected with the oil inlets of the two hydraulic quantitative motors 15 with the same structure through the high-pressure oil pipeline, and the oil outlets of the two hydraulic quantitative motors 15 with the same structure are connected with the axially inclined The oil inlet of the disc-type high-pressure variable pump 9 is sealed and connected through a high-pressure oil pipeline to form a hydraulic circuit. The output rotor shafts of the two hydraulic quantitative motors 15 with the same structure are connected with the half shafts of the two front wheels 7 through gear meshing. By driving the output rotor shaft of the hydraulic quantitative motor 15 to rotate, the hydraulic energy pumped by the axial swash plate type high-pressure variable pump 9 is converted into mechanical energy to drive the front wheel 7 .

According to a hydraulic auxiliary driving and braking system provided by the utility model, the oil outlet of the electro-hydraulic proportional overflow valve 11 and the oil inlet of the heat exchanger 12 are sealed and connected through a low-pressure oil pipeline, and the oil outlet of the heat exchanger 12 is sealed. The oil outlet and the oil tank 13 are sealed and connected through a low-pressure oil pipeline, and the electro-hydraulic proportional overflow valve 11, the heat exchanger 12 and the oil tank 13 are arranged in series.

According to a hydraulic auxiliary driving and braking system provided by the utility model, the rated pressure of the two hydraulic quantitative motors 15 with the same structure is 40MPa, and the displacement is 1043ml/r; A high-pressure P90 pump with a capacity of 75ml/r and a maximum speed of 3600rpm; the median function of the three-position four-way electromagnetic reversing valve 10 is H-shaped, all four ports are connected, the pump is unloaded, and the operation method is electromagnet operation, spring reset, The position of the spool can be adjusted left and right; the electro-hydraulic proportional relief valve 11 is a high-pressure proportional relief valve with a pressure regulating range of 0-40MPa; the heat exchanger 12 adopts a water-cooled cooler with an operating temperature of 40-60°C; the safety valve Group 14 consists of two safety valves with the same structure and type with a pressure limit of 40MPa, and the installation positions of the two safety valves are opposite.

According to the control method of the hydraulic auxiliary driving and braking system provided by the utility model, the electronic control unit 8 collects the vehicle speed signal, the rotational speed signal of the engine 1, the position signals of the accelerator pedal 18 and the brake pedal 19, and the hydraulic system switch key signal to judge the driver's intention and the vehicle's driving state, thereby controlling the axial swash plate type high-pressure variable pump 9, the spool position of the three-position four-way electromagnetic reversing valve 10, the electro-hydraulic proportional relief valve 11 and the throttle opening of the engine 1 To achieve switching between hydraulic auxiliary drive and braking system switches and working modes, specifically including the following steps:

Step 1, collecting vehicle speed signal, accelerator pedal 18 position signal, brake pedal 19 position signal and hydraulic system switch signal;

Step 2, judge whether the vehicle speed is greater than 0, if so, go to step 3; otherwise, it means that the vehicle is in a parked state, go to step 10;

Step 3, judge whether the vehicle is braked according to the vehicle speed, accelerator pedal 18 and brake pedal 19 position signals, if so, enter step 4; otherwise, enter step 5;

Step 4, the vehicle is in the braking state, and the hydraulic system is turned on to enter the retarding brake working mode: the electronic control unit 8 sends an instruction to adjust the spool of the three-position four-way electromagnetic reversing valve 10 to the right position, and the P port and the B port, T port and A port are connected, and the inclination angle of the swash plate of the axial swash plate type high-pressure variable pump 9 is adjusted to the maximum, and at the same time, the electronic control unit 8 calculates the reverse drive torque of the hydraulic system according to the vehicle speed signal and the brake demand torque. , send an instruction to the electro-hydraulic proportional relief valve 11 to adjust the oil outlet pressure of the variable pump 9, and return to step 2;

Step five, judging whether the hydraulic system switch is on, if so, go to step six, otherwise go to step seven;

Step 6, the driver activates the hydraulic system to enter the auxiliary driving mode: the electronic control unit 8 sends an instruction to adjust the spool of the three-position four-way electromagnetic reversing valve 10 to the left position, and the P port is connected to the A port, and the T port is connected to the B port. Through, the axial swash plate type high-pressure variable pump 9 is connected with two hydraulic quantitative motors 15 through the safety valve group 14, and the power required by the hydraulic quantitative motor 15 of the front wheels is calculated according to the rotation speed signal of the engine 1 and the vehicle speed signal, and the electronic control unit 8. Send an instruction to the variable pump 9 to adjust the inclination angle of its swash plate to provide a suitable driving force for the hydraulic quantitative motor 15, and return to step 2;

Step seven, judging whether the vehicle speed is greater than the set limit value of the vehicle speed, if so, proceed to step eight; otherwise, proceed to step nine;

Step 8, when the vehicle speed is greater than the set limit value of the vehicle speed, the hydraulic system is closed, and the whole vehicle is in the engine-only drive mode, the electronic control unit 8 sends an instruction to adjust the spool of the three-position four-way electromagnetic reversing valve 10 to move to the neutral position, and the A port, Port B, port P, and port T are connected to each other, and the axial swash plate type high-pressure variable pump 9 and hydraulic quantitative motor 15 are both in an idling state, and return to step 2;

Step 9, when the vehicle speed is lower than the set limit value of the vehicle speed, the hydraulic system is automatically turned on and enters the auxiliary drive working mode, that is, enters step 6;

Step ten, end.

Compared with the prior art, the beneficial effects of the utility model are:

1. Compared with the motor, the hydraulic quantitative motor and hydraulic variable pump used in the hydraulic auxiliary system of the utility model have higher specific power, smaller volume, lighter weight, less space on the vehicle, and simple installation structure. For example, the specific power of the motor is about 1.6kw/kg, while the specific power of the hydraulic motor can reach 3.6kw/kg.

2. Compared with traditional vehicles, the hydraulic auxiliary system of this utility model has strong adaptability to multiple working conditions, and can significantly improve the power, passability and climbing ability of the vehicle. On roads with a road adhesion coefficient of 0.34-0.57, The ratio of increased traction is about 10%-23%, and the ratio of increased climbing is about 13%-25%.

3. Compared with the traditional vehicle, the hydraulic auxiliary system of the utility model can significantly increase the braking torque when the vehicle is braking, and at the same time, it can significantly reduce the heat generation of the brake disc during the long-term driving and braking, and improve the length of the vehicle. Stability of braking performance during braking over time.

4. The hydraulic auxiliary system of the utility model is formed by adding some hydraulic components on the basis of the structure of the existing vehicle, which basically does not change the structure of the original vehicle. increase less.

5. The hydrostatic drive adopted by the hydraulic auxiliary system of the utility model is safer than the electric drive controlled by high voltage.

Description of drawings

Below in conjunction with accompanying drawing, the utility model is further described:

Fig. 1 is a schematic diagram of the structural principle of the hydraulic auxiliary driving and braking system of the present invention.

Fig. 2 is a power transmission route diagram of the hydraulic auxiliary driving and braking system of the present invention under the engine independent driving mode.

Fig. 3 is a power transmission route diagram of the hydraulic auxiliary driving and braking system of the present invention under the hydraulic auxiliary driving mode.

Fig. 4 is a power transmission route diagram of the hydraulic auxiliary driving and braking system of the present invention under the hydraulic retarding braking mode.

Fig. 5 is a flow chart of the control method for switching the working mode of the hydraulic auxiliary driving and braking system of the present invention.

Fig. 6 is a graph showing the increase ratio of vehicle traction force of the hydraulic auxiliary driving and braking system of the present invention.

Fig. 7 is a graph showing the increase ratio of vehicle gradeability of the hydraulic auxiliary driving and braking system of the present invention.

In the figure: 1—engine, 2—clutch, 3—power take-off, 4—gearbox, 5—rear drive axle, 6—rear wheel, 7—front wheel, 8—electronic control unit, 9—axial swash plate Type high-pressure variable pump, 10—three-position four-way electromagnetic reversing valve, 11—electro-hydraulic proportional overflow valve, 12—heat exchanger, 13—oil tank, 14—safety valve group, 15—hydraulic quantitative motor, 16— Engine crankshaft output shaft, 17—the output shaft of the engine-driven accessories, 18—accelerator pedal, 19—brake pedal.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is described in detail:

The purpose of this utility model is to install a set of hydraulic system on the structural basis of existing commercial trucks to overcome the shortcomings of poor power and passability on bad roads and unstable braking for a long time when going down long slopes, and to improve car performance.

Referring to Fig. 1, the hydraulic auxiliary driving and braking system provided by the utility model includes an engine 1, a clutch 2, a power take-off 3, a gearbox 4, a rear drive axle 5, two rear wheels 6, two front wheels 7, a vehicle Frame, electronic control unit 8, axial swash plate high-pressure variable pump 9, three-position four-way electromagnetic reversing valve 10, electro-hydraulic proportional overflow valve 11, heat exchanger 12, oil tank 13, safety valve group 14, two A hydraulic quantitative motor 15 with the same structure, an output shaft 16 of an engine crankshaft, an output shaft 17 of an engine-driven accessory, an accelerator pedal 18 and a brake pedal 19.

Engine 1, clutch 2, gearbox 4, rear drive axle 5, two rear wheels 6, two front wheels 7 and vehicle frame in the system described in the utility model are the power sources and power transmission parts of existing traditional vehicles, take Force device 3, axial swash plate type high-pressure variable pump 9, three-position four-way electromagnetic reversing valve 10, electro-hydraulic proportional overflow valve 11, heat exchanger 12, safety valve group 14, two hydraulic quantitative motors with the same structure 15. The oil tank 13 and the electronic control unit 8 are components added on the basis of not changing the transmission structure of the existing traditional vehicle, and form a new power transmission route.

The hydraulic auxiliary driving and braking system provided by the utility model is formed by adding some elements on the basis of not changing the existing traditional vehicle structure.

In the traditional vehicle structure, the crankshaft output shaft 16 of the engine 1 is connected with the input spline pair of the clutch 2, the output shaft of the clutch 2 is connected with the input shaft of the gearbox 4 by a spline pair, and the output shaft of the gearbox 4 is connected with the rear drive axle 5. The input shaft is connected by a spline pair; the output shaft of the clutch 2 and the input shaft of the gearbox 4 are installed on their respective housings through rolling bearings and are in the same horizontal plane, keeping the rotation axes parallel to each other; the gear of the input shaft of the gearbox 4 and the output The shaft gear sleeve is fixedly connected on its input shaft and output shaft, and its input shaft gear is meshed with the output shaft gear; in the same horizontal plane and keep the axes of rotation parallel to each other. The engine 1 outputs power as a power source, which is transmitted to the rear drive axle 5 through the clutch 2 and the gearbox 4 to drive the rear wheels 6 .

In the newly added structure, the input shaft of the power take-off 3 and the output shaft 17 of the engine drive accessory are connected by a spline pair, and the meshing transmission of the input shaft driving gear of the power take-off 3 and the driven gear of the output shaft drives the engine 1 The power is transmitted to the output shaft of the power take-off 3, and the output shaft of the power take-off 3 and the rotor shaft of the axial swash plate type high-pressure variable pump 9 are connected by a flange, so that the rotation of the engine 1 passes through the power take-off 3 Drive the rotor shaft of the axial swash plate type high-pressure variable pump 9 to rotate synchronously, and pump oil out.

The oil outlet of the axial swash plate type high-pressure variable pump 9 is sealed with the P port of the three-position four-way electromagnetic reversing valve 10 through a high-pressure oil pipeline, and the A port of the three-position four-way electromagnetic reversing valve 10 is connected with the safety valve The oil inlet of group 14 is sealed and connected through a high-pressure oil pipeline, and the B port of the three-position four-way electromagnetic reversing valve 10 is connected with the oil inlet of the electro-hydraulic proportional relief valve 11 through a high-pressure oil pipeline. The T port of the electromagnetic reversing valve 10 and the oil tank 13 are sealed and connected through a low-pressure oil pipeline; the three-position four-way electromagnetic reversing valve 10 realizes the difference between the P port and the A port, B port, and T port by adjusting the position of the spool. The connected position controls the oil outlet of the axial swash plate type high-pressure variable pump 9 to connect to different hydraulic circuits.

The oil outlet of the safety valve group 14 is connected with the oil inlets of the two hydraulic quantitative motors 15 with the same structure installed on the hubs of the two front wheels 7 through a high-pressure oil pipeline. The oil outlet and the oil inlet of the axial swash plate type high-pressure variable pump 9 fixed on the vehicle frame are sealed and connected through a high-pressure oil pipeline to form a hydraulic circuit, and the output rotor shafts of two hydraulic quantitative motors 15 with the same structure The half-shafts of the two front wheels 7 are meshed with gears, and the hydraulic energy pumped by the axial swash plate type high-pressure variable pump 9 is converted into mechanical energy by driving the output rotor shaft of the hydraulic quantitative motor 15, and then transmitted to and driven front wheel7.

The oil outlet of the electro-hydraulic proportional overflow valve 11 is sealed and connected to the oil inlet of the heat exchanger 12 through a low-pressure oil pipeline, and the oil outlet of the heat exchanger 12 is connected to the oil tank 13 through a low-pressure oil pipeline. Serial settings.

The electronic control unit 8 is respectively connected with the engine 1, the axial swash plate type high-pressure variable pump 9, the three-position four-way electromagnetic reversing valve 10, the electro-hydraulic proportional overflow valve 11, the accelerator pedal 18 and the brake pedal 19 through signal lines, Receive the position signals of the accelerator pedal 18 and the brake pedal 19, and send instructions to adjust the throttle opening of the engine 1, the inclination angle of the swash plate of the axial swash plate type high-pressure variable pump 9, and the valve of the three-position four-way electromagnetic reversing valve 10. Spool position and the relief pressure of the electro-hydraulic proportional relief valve 11.

When the vehicle is running on a good road, the rear wheel 6 can fully utilize the output power of the engine 1. At this time, the clutch 2 is engaged, and the electronic control unit 8 sends a three-position four-way electromagnetic signal according to the driver's intention and the driving state of the vehicle. The reversing valve 10 sends instructions to adjust the position of its spool, so that the P port and the T port are connected, and the oil outlet of the axial swash plate type high-pressure variable pump 9 is directly connected to the oil tank 13. At this time, the axial swash plate type The load of the high-pressure variable pump 9 is zero, so the load applied by the axial swash plate type high-pressure variable pump 9 to the engine 1 through the power take-off 3 is also zero; , gearbox 4, and clutch 2 to transmit the running resistance of the vehicle, so all the power output by engine 1 is transmitted to the rear drive axle 5 through clutch 2, gearbox 4, and drives the rear wheel 6; the axial swash plate type high-pressure variable pump 9 in idle state.

When the vehicle is running on a bad road surface, the rear wheel 6 slips and the output power of the engine 1 cannot be fully utilized. The four-way electromagnetic reversing valve 10 sends instructions to adjust the position of its spool, so that the P port and the A port are connected, and the oil outlet of the axial swash plate type high-pressure variable pump 9 is installed on the hub of the front wheel 7 through the safety valve group 14 The oil inlets of the two hydraulic quantitative motors 15 are connected, and the load of the front wheels 7 is loaded to the engine 1 through the hydraulic quantitative motors 15, the axial swash plate type high-pressure variable pump 9 and the power take-off 3 . Part of the power output by the engine 1 is transmitted to the rear drive axle 5 through the clutch 2 and the gearbox 4 to drive the rear wheel 6; the other part of the power is driven by the power take-off 3 to drive the axial swash plate type high-pressure variable pump 9 to input the rotor shaft to rotate, electronically controlled The unit 8 determines the auxiliary drive power that the engine 1 can provide to the two front wheels 7 according to the engine output power and the slip ratio of the rear wheels, and sends instructions to the axial swash plate type high-pressure variable pump 9 to adjust its displacement, and the axial slant The disc-type high-pressure variable pump 9 converts the mechanical energy transmitted by the engine 1 into hydraulic energy, and drives two hydraulic quantitative motors 15 to rotate after the pressure is limited by the safety valve group 14, and the hydraulic quantitative motor 15 converts the hydraulic energy into mechanical energy to drive the front wheels 7 .

When the vehicle brakes, especially when driving on a long downhill slope for a long time, the engine 1 is not used as a power source to output power, and the kinetic energy of the vehicle when the vehicle is braked is used as a power source. 6. The transmission system formed by the clutch 2 outputs power. At this time, the clutch 2 is engaged, and the electronic control unit 8 sends an instruction to the three-position four-way electromagnetic reversing valve 10 to adjust its spool position according to the driving state of the vehicle, so that the P port and the B port are connected to make the axial swash plate high pressure The oil outlet of the variable pump 9 is connected to the electro-hydraulic proportional relief valve 11, and the oil return port of the electro-hydraulic proportional relief valve 11 is connected to the heat exchanger 12 through the hydraulic pipeline. After the device 12 is cooled, it returns to the oil tank 13. The power passes through the rear drive axle 5, the gearbox 4, the clutch 2, the engine 1 and the power take-off 3 from the rear wheel 6, and drives the rotor shaft of the axial swash plate type high-pressure variable pump 9 to rotate synchronously to pump out oil. The pressure of the pumped oil is linearly regulated by the electro-hydraulic proportional relief valve 11 . The driving torque of the axial swash plate type high-pressure variable pump 9 is equal to the reverse torque of its drive gear, and the reverse torque reacts on the rear drive axle 5 through the power take-off 3, engine 1, clutch 2 and gearbox 4, Produce braking effect on the whole vehicle. The electronic control unit 8 sends corresponding instructions to the electro-hydraulic proportional relief valve 11 according to the position of the brake pedal 19, and adjusts the outlet oil pressure of the axial swash plate type high-pressure variable pump 9 to a certain value, and the axial swash plate type The reverse torque that appears on the rotor shaft of the high-pressure variable pump 9 acts on the engine 1 through the power take-off 3. At this time, the engine 1 is not used as a power source, but as a braking load on the transmission shaft. The braking torque transmitted by the high-pressure variable pump 9 is transmitted through the clutch 2 and the gearbox 4. The braking torque is amplified by the rear drive axle 5 and acts on the rear wheels 6 to consume the kinetic energy of the whole vehicle to realize auxiliary braking. .

The specific working mode of the hydraulic auxiliary driving and braking system provided by the utility model is shown in the following table:

Operating mode:

1) Engine alone driving mode

Referring to Figure 2, the vehicle is running on a good and normal road at this time, the rear wheel 6 (drive wheel) is not slipping, the torque required for the operation of the vehicle is provided by the engine 1 alone, the clutch 2 is combined, and the three-position four-way electromagnetic reversing valve 10 The spool is in the middle position, the four ports A, B, P, and T communicate with each other, and the axial swash plate type high-pressure variable pump fixedly installed on the frame 9 The oil outlet is directly connected to the oil tank 13, and the load is zero. Therefore, the load applied to the engine 1 by the axial swash plate type high-pressure variable pump 9 through the power take-off 3 is also zero; at this time, the load of the engine 1 is only transmitted through the rear wheels 6, the rear drive axle 5, the gearbox 4, and the clutch 2 The driving resistance of the vehicle; the two structurally identical hydraulic quantitative motors 15 installed on the front wheel 7 hubs do not work, and the load is also zero, keeping the idling state. Now the power of the engine 1 is transmitted to the rear drive axle 5 through the clutch 2 and the gearbox 4 to directly drive the rear wheels 6 . The power transmission route is shown in Figure 2.

2) Hydraulic auxiliary drive mode

Referring to FIG. 3 , when the vehicle is running on a bad road surface, the rear wheel 6 (drive wheel) slips, and only part of the power transmitted by the engine 1 is utilized. At this time, the clutch 2 is engaged, and the electronic control unit 8 adjusts the spool of the three-position four-way electromagnetic reversing valve 10 to move to the left position according to the driver's intention or the driving state of the vehicle, and the P port is connected to the A port, and the T port is connected to the B port. The hydraulic auxiliary drive system is opened, and the oil outlet of the axial swash plate type high-pressure variable pump 9 is connected to the oil inlet of two hydraulic motors 15 with the same structure installed on the hub of the front wheel 7 through the safety valve group 14 . The axial swash plate type high-pressure variable pump 9 obtains part of the power of the engine 1 through the power take-off 3, converts the mechanical energy into hydraulic energy, passes through the safety valve group 14, and supplies the two identical structures installed on the hub of the front wheel 7. The hydraulic motor 15 provides high-pressure oil, and the high-pressure oil drives the two hydraulic motors 15 to convert the hydraulic energy into mechanical energy to drive the two front wheels 7; the other part of the power of the engine 1 is transmitted to the rear drive axle 5 through the clutch 2 and the gearbox 4 to drive the two front wheels. 6 rear wheels, so as to realize the transformation from two rear-wheel drive vehicles to four-wheel drive vehicles. Simultaneously, the electronic control unit 8 determines the size of the auxiliary drive power that the engine 1 can provide to the two front wheels 7 according to different slip ratios and the power of the engine 1 at this time, and the electronic control unit 8 determines according to the conversion relationship between the component powers, Calculate the driving power of the variable pump 9, and control the inclination of the swash plate of the variable pump 9 to provide suitable driving force for the two hydraulic quantitative motors 15 mounted on the hubs of the two front wheels 7. The power transmission route is shown in Figure 3.

3) Hydraulic slow braking mode

Referring to Fig. 4, when the vehicle brakes, especially when the vehicle is braked for a long time when going down a long slope, the traditional brake will have a phenomenon of brake heat fading, and the braking torque will be unstable. At this time, the electronic control unit 8 adjusts the spool of the three-position four-way electromagnetic reversing valve 10 to the right position according to the signal of the brake pedal 19, the P port is connected to the B port, and the T port is connected to the A port. The oil outlet of the variable pump 9 is connected to the circuit of the electro-hydraulic proportional valve 11, and at the same time, the inclination angle of the swash plate of the axial swash plate type high-pressure variable pump 9 is adjusted to the maximum, and the hydraulic retarding braking mode is turned on.

The power transmission route in this mode is shown in Figure 4. At this time, the power source is the vehicle kinetic energy transmitted forward from the rear wheel 6, and the participating components mainly include the axial swash plate type high-pressure variable pump 9 and the electro-hydraulic proportional relief valve. 11. Heat exchanger 12 and oil tank 13. The power transmitted from the rear wheel 6 passes through the gearbox 4, the clutch 2, the engine 1 and the power take-off 3, and drives the rotor shaft of the axial swash plate type high-pressure variable pump 9 to rotate synchronously to pump out oil. The oil outlet of the axial swash plate type high-pressure variable pump 9 is connected to the electro-hydraulic proportional relief valve 11, the pressure of the pumped oil is linearly regulated by the electro-hydraulic proportional relief valve 11, and the electro-hydraulic proportional relief valve 11 The oil return port is connected to the heat exchanger 12 through a hydraulic pipeline, and the hydraulic oil whose temperature rises after absorbing the kinetic energy of the vehicle flows back to the oil tank 13 after being cooled by the heat exchanger 12 . The driving torque of the axial swash plate type high-pressure variable pump 9 is equal to the reverse torque of its drive gear, and the reverse torque is reacted to the engine 1 through the power take-off 3. At this time, the engine 1 is not used as a power source, but as a The load on the drive shaft. The braking load of the engine 1, together with the reverse torque of the axial swash plate type high-pressure variable pump 9, reacts on the rear drive axle 5 through the clutch 2 and the gearbox 4 to produce a braking effect on the whole vehicle. Obviously, when the outlet pressure of the axial swash plate type high-pressure variable pump 9 is low, the required driving torque is small, and the counter-driving torque to the vehicle is small; by adjusting the pressure of the electro-hydraulic proportional relief valve 11 That is, the outlet pressure of the axial swash plate type high-pressure variable pump 9 can be adjusted, thereby adjusting the counter-driving torque. When braking is required, the electronic control unit 8 sends a corresponding command to the electro-hydraulic proportional relief valve 11 according to the position of the brake pedal, and adjusts the outlet oil pressure of the axial swash plate type high-pressure variable pump 9 to a certain value. At this time, the reverse torque appears on the driving gear of the axial swash plate type high-pressure variable pump 9, plus the braking load of the engine 1, after being amplified by the gearbox 4 and the rear drive axle 5, it acts on the rear wheels 6 to achieve a positive impact on the vehicle. The purpose of slow braking.

When the vehicle is fully loaded with 100t and the first gear ratio of the gearbox is 12.1, the ratio of the traction force and the ratio of gradeability that can be improved by the hydraulic auxiliary system described in the utility model can be calculated, as shown in Fig. 6 and Fig. 7 . Simultaneously when the hydraulic system is in slow braking mode, the transmission ratio of the power take-off 3 used in the system of the utility model is 1:2, the maximum rotating speed of the hydraulic pump 9 is 3600rpm, and the maximum displacement is 75ml/r , the highest output hydraulic oil pressure is 40MPa, the first gear ratio of the vehicle is 12.1, and the main reduction ratio is 5.73. After calculation, the hydraulic pump in the utility model can additionally provide a maximum braking torque of 477.7Nm, which is amplified by the transmission mechanism , the braking torque acting on the rear wheels can reach 66240.7Nm.

In the structure of the hydraulic auxiliary driving and braking system provided by the utility model:

The engine 1 is the common power source of the traditional vehicle and the hydraulic auxiliary drive and braking system. It is selected according to the power requirements of the vehicle, and the existing product is selected, such as the WP12_375NW engine with a maximum output power of 295KW.

Clutch 2 selects existing products for use, and the structure is a common normally closed diaphragm spring friction clutch commonly used in commercial trucks, such as a DS430 type clutch with a friction plate diameter of 430mm.

The gearbox 4 selects an existing product according to the gear position requirements of the vehicle, such as a mechanical gearbox whose model is 12JSD180TA.

The power take-off mode of the power take-off 3 is to take power directly from the engine 1 end, which can be selected from existing products; the structure of the power take-off 3 includes two intermeshing driving and driven gears, the driving gear and the driven gear are respectively The sleeve is fixedly connected on the input shaft and the output shaft, and the power is transmitted from the input shaft, through the meshing transmission of the main and driven gears, and then transmitted from the output shaft.

The axial swash plate type high-pressure variable pump 9 and the hydraulic quantitative motor 15 are selected according to the power requirements of the vehicle. For example, the high-pressure P90 pump with a displacement of 75ml/r and a maximum speed of 3600rpm has a rated pressure of 40MPa and a displacement of The radial piston motor MFE08-0 is 1043ml/r.

The three-position four-way electromagnetic reversing valve 10 is selected from existing products, and its position function is H-shaped, the four ports are fully connected, the pump is unloaded, the operation mode is electromagnet operation, and the spring resets; according to the input electric signal instruction, the valve core The position can be adjusted left and right to realize the reversing function.

The electro-hydraulic proportional overflow valve 11 is a high-pressure proportional overflow valve with a pressure regulating range of 0-40MPa, which is an existing product.

The heat exchanger 12 adopts a water-cooled cooler with an operating temperature of 40-60° C., which is an existing product.

The safety valve group 14 is composed of two safety valves with the same structural model, the safety valves are selected from existing products with a pressure limit of 40MPa, and the installation positions of the two safety valves are opposite.

The control method of the working mode switching of the hydraulic auxiliary driving and braking system provided by the utility model is specifically described as follows:

Referring to Fig. 5, the electronic control unit 8 judges the intention of the driver and the driving state of the vehicle by collecting the vehicle speed signal, the rotational speed signal of the engine 1, the position signals of the accelerator pedal 18 and the brake pedal 19, and the key signal of the hydraulic system switch, thereby controlling the axial direction. The swash plate type high-pressure variable pump 9, the position of the spool of the three-position four-way electromagnetic reversing valve 10, the electro-hydraulic proportional relief valve 11 and the throttle opening of the engine 1 realize the switching and working mode of the hydraulic auxiliary drive and the braking system The conversion, specifically includes the following steps:

Step 1, collecting vehicle speed signal, accelerator pedal position signal, brake pedal position signal and hydraulic system switch signal;

Step 2, determine whether the vehicle speed is greater than 0, if so, enter step 3; otherwise, it means that the vehicle enters the end step of step 10 in the parking state;

Step 3, judge whether the vehicle is braking according to the vehicle speed, accelerator pedal and brake pedal position signals, if so, go to step 4; otherwise, go to step 5;

Step 4, the vehicle is in the braking state, and the hydraulic system is turned on to enter the retarding braking working mode:

The electronic control unit 8 sends instructions to adjust the spool of the three-position four-way electromagnetic reversing valve 10 to move to the right position, the P port is connected to the B port, and the T port is connected to the A port, and the slant of the axial swash plate type high-pressure variable pump 9 is adjusted. The inclination angle of the disc is the largest, and at the same time, the electronic control unit 8 calculates the reverse drive torque of the hydraulic system according to the vehicle speed signal and the braking demand torque, and sends instructions to the electro-hydraulic proportional relief valve 11 to adjust the axial swash plate type high pressure variable The oil outlet pressure of pump 9 returns to step 2;

Step five, judging whether the hydraulic system switch is on, if so, go to step six, otherwise go to step seven;

Step 6, the driver starts the hydraulic system and enters the auxiliary drive working mode:

The electronic control unit 8 sends instructions to adjust the spool of the three-position four-way electromagnetic reversing valve 10 to the left position, the P port is connected to the A port, and the T port is connected to the B port, and the axial swash plate high-pressure variable pump 9 passes through the safety valve. The group 14 is connected with two hydraulic quantitative motors 15 installed on the hubs of the two front wheels 7, and the required power of the hydraulic quantitative motors 15 of the front wheels is calculated according to the rotational speed signal of the engine 1 and the vehicle speed signal, and the electronic control unit 8 directs the variable pump 9. Send an instruction to adjust the inclination angle of the swash plate to provide suitable driving force for the two hydraulic quantitative motors 15 mounted on the hubs of the two front wheels 7, and return to step 2;

Step 7, judging whether the vehicle speed is greater than the set limit value of the vehicle speed, if so, proceed to step 8, otherwise proceed to step 9;

Step 8, if the vehicle speed is greater than the set limit value of the vehicle speed, it means that the vehicle is running on a good road, the hydraulic system is closed, and the whole vehicle is in the engine-only driving mode. At this time, the electronic control unit 8 sends an instruction to adjust the spool of the three-position four-way electromagnetic reversing valve 10 to move to the neutral position, and the A port, B port, P port, and T port are connected to each other), and the axial swash plate type high-pressure variable pump 9 and hydraulic motor 15 are all in idling state, return to step 2;

Step 9, if the vehicle speed is lower than the set limit value of the vehicle speed, it means that the vehicle is driving on a bad road surface, and the hydraulic system automatically turns on and enters the auxiliary drive working mode, that is, enters step 6;

Step ten, end.

Claims (5)

1. a hydraulic pressure assistive drive and brake system, comprise driving engine (1), power-transfer clutch (2), change speed gear box (4), rear driving axle (5), two trailing wheels (6), two front-wheels (7), acceleration pedal (18), brake pedal (19) and vehicle frame, the crank shaft output shaft (16) of described driving engine (1) adopts spline pair to be connected with the input shaft of power-transfer clutch (2), the output shaft of power-transfer clutch (2) adopts spline pair to be connected with the input shaft of change speed gear box (4), and the output shaft of change speed gear box (4) adopts spline pair to be connected with the input shaft of rear driving axle (5); It is characterized in that, also comprise power takeoff (3), axial inclined disc type high pressure controllable capacity pump (9), 3-position 4-way solenoid directional control valve (10), electricity liquid ratio relief valve (11), H Exch (12), safety valve group (14), 2 hydraulic pressure fixed displacement motor (15), oil tank (13) and electronic control units (8) that structure is identical, wherein, the input shaft of described power takeoff (3) adopts spline pair to be connected with the output shaft (17) of engine drive annex, and the output shaft of power takeoff (3) is connected by flange with the rotor shaft of axial inclined disc type high pressure controllable capacity pump (9); Axial inclined disc type high pressure controllable capacity pump (9) is connected with 3-position 4-way solenoid directional control valve (10) pipeline, and 3-position 4-way solenoid directional control valve (10) is connected with safety valve group (14), electricity liquid ratio relief valve (11), oil tank (13) pipeline respectively; The oil inlet pipeline of the hydraulic pressure fixed displacement motor (15) that the oil outlet of safety valve group (14) is identical with 2 structures connects, and the oil outlet of the hydraulic pressure fixed displacement motor (15) that 2 structures are identical is connected with the oil inlet pipeline of axial inclined disc type high pressure controllable capacity pump (9); The oil outlet of described electricity liquid ratio relief valve (11) is connected with the oil inlet pipeline of H Exch (12), and the oil outlet of H Exch (12) is connected with oil tank (13) pipeline; Electronic control unit (8) is connected with driving engine (1), axial inclined disc type high pressure controllable capacity pump (9), 3-position 4-way solenoid directional control valve (10), electricity liquid ratio relief valve (11), acceleration pedal (18) and brake pedal (19) respectively by signal wire (SW).

2. a kind of hydraulic pressure assistive drive as claimed in claim 1 and brake system, it is characterized in that, described axial inclined disc type high pressure controllable capacity pump (9) is connected with 3-position 4-way solenoid directional control valve (10) pipeline, 3-position 4-way solenoid directional control valve (10) respectively with safety valve group (14), the connection of electricity liquid ratio relief valve (11) pipeline refers to: the oil outlet of axial inclined disc type high pressure controllable capacity pump (9) is connected by high-voltage oil liquid seal for pipe joints with the P mouth of 3-position 4-way solenoid directional control valve (10), the A mouth of 3-position 4-way solenoid directional control valve (10) is connected by high-voltage oil liquid seal for pipe joints with the oil inlet of safety valve group (14), the B mouth of 3-position 4-way solenoid directional control valve (10) is connected by high-voltage oil liquid seal for pipe joints with the oil inlet of electricity liquid ratio relief valve (11), the T mouth of 3-position 4-way solenoid directional control valve (10) is connected by the seal for pipe joints of low pressure fluid with oil tank (13).

3. a kind of hydraulic pressure assistive drive as claimed in claim 1 and brake system, it is characterized in that, the hydraulic pressure fixed displacement motor (15) that described 2 structures are identical is arranged on the wheel hub of two front-wheels (7) successively, and axial inclined disc type high pressure controllable capacity pump (9) is fixed on vehicle frame; The oil inlet of the hydraulic pressure fixed displacement motor (15) that the oil outlet of described safety valve group (14) is identical with 2 structures connects by high-voltage oil liquid seal for pipe joints, the oil outlet of the hydraulic pressure fixed displacement motor (15) that 2 structures are identical is connected by high-voltage oil liquid seal for pipe joints with the oil inlet of axial inclined disc type high pressure controllable capacity pump (9), and 2 the identical output rotor axle of hydraulic pressure fixed displacement motor (15) and semiaxis of two front-wheels (7) of structure adopt gears to be connected with a joggle.

4. a kind of hydraulic pressure assistive drive as claimed in claim 1 and brake system, it is characterized in that, the oil outlet of described electricity liquid ratio relief valve (11) is connected by the seal for pipe joints of low pressure fluid with the oil inlet of H Exch (12), the oil outlet of H Exch (12) is connected by the seal for pipe joints of low pressure fluid with oil tank (13), electricity liquid ratio relief valve (11), H Exch (12) and oil tank (13) serial setting.

5. a kind of hydraulic pressure assistive drive as claimed in claim 1 and brake system, is characterized in that, the rated pressure of the hydraulic pressure fixed displacement motor (15) that described 2 structures are identical is 40MPa, and discharge capacity is 1043ml/r; Described axial inclined disc type high pressure controllable capacity pump (9) is discharge capacity 75ml/r, high pressure P 90 pumps of maximum speed of revolution 3600rpm; The Median Function of described 3-position 4-way solenoid directional control valve (10) is H shape, and four-hole is connected entirely; The high-voltage ratio by pass valve that described electricity liquid ratio relief valve (11) is 0-40MPa for range of regulation; Described H Exch (12) employing operating temperature is the water-cooled cooler of 40-60 ℃; Described safety valve group (14) is comprised of two identical safety valves of structure model of pressure limiting 40MPa, and the installation site of two safety valves is contrary.

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