Mine dump truck drive-by-wire proportional unmanned braking system and use method

Abstract

The application discloses a mine self-unloading truck linear control positive proportion unmanned braking system and a use method thereof, and belongs to the field of mining equipment. The mine self-unloading truck linear control positive proportion unmanned braking system comprises a hydraulic pump connected with an oil tank, and a front braking system and a rear braking system connected with the hydraulic pump through a brake valve group. The front braking system comprises a double-way brake valve, a front braking proportional valve group, a front brake valve group and a front axle dry brake. The mine self-unloading truck linear control positive proportion unmanned braking system and the use method thereof are characterized in that the linear control braking is connected in parallel with the manual operation braking, the vehicle can be quickly braked no matter which side sends a braking instruction, the manual operation braking and the linear control remote braking function are realized at the same time, the original hydraulic system is slightly changed, the vehicle is convenient to transform, and the strength is low.

Description

Technical Field

[0001] This invention relates to the field of mining machinery technology, specifically to a wire-controlled proportional unmanned driving braking system for mining dump trucks and its usage method. Background Technology

[0002] Mining dump trucks operate on complex open-pit mine roads, characterized by narrow, steep slopes, muddy and waterlogged conditions during rain, high environmental noise, and dusty conditions during windy weather. Unmanned dump trucks face harsh operating conditions, require coordinated vehicle operation, and frequently change work sites. Braking is complicated by various unfavorable factors such as heavy-load downhill driving and sudden stops. Furthermore, the remote-controlled brake-by-wire system places new demands on braking performance and response time, requiring the system to provide remote-controlled brake-by-wire functionality while retaining the manual braking capability of conventional models, and also possessing emergency braking capabilities in case of power failure. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a simple and effective wire-controlled proportional unmanned braking system for mining dump trucks and its usage method.

[0004] The present invention is achieved by the following technical solution: a wire-controlled proportional unmanned driving braking system for mining dump trucks, including a hydraulic pump connected to an oil tank, wherein the hydraulic pump is connected to a front braking system and a rear braking system through a brake valve group;

[0005] The front braking system includes a dual-way brake valve, a front brake proportional valve group, a front brake valve group, and a front axle dry brake.

[0006] The front brake valve assembly includes solenoid directional valve I, pressure reducing valve I, and solenoid directional valve II.

[0007] The front brake proportional valve assembly includes filter element I, proportional valve core I, relay valve I, and shuttle valve I. The front brake proportional valve assembly has two oil inlet ends. One oil inlet end is connected to the oil inlet ends of proportional valve core I and relay valve I respectively through filter element I. The oil outlet end of proportional valve core I is connected to the control end of relay valve I. The oil outlet end of relay valve I is connected to the other oil inlet end of the front brake proportional valve assembly through shuttle valve I. The oil outlet end of shuttle valve I is connected to solenoid directional valve II.

[0008] The rear braking system includes a dual-path brake valve, a hydraulic retardation valve, a rear brake proportioning valve group, a rear brake valve, and a rear axle wet brake.

[0009] The rear brake valve includes an overflow valve, a damper, a filter, and a pressure reducing valve II;

[0010] The rear brake proportional valve assembly includes a proportional valve core II, a shuttle valve III, a shuttle valve IV, a relay valve II, and a filter element II. The oil inlet end of the filter element II is connected to the oil inlet end of the rear brake proportional valve assembly. The oil outlet end of the filter element II is connected to the oil inlet ends of both the proportional valve core II and the relay valve II. The oil outlet end of the proportional valve core II is connected to the control end of the relay valve II via the shuttle valve III. The oil outlet end of the relay valve II is connected to the service piston chamber of the rear axle wet brake via the shuttle valve IV. The shuttle valve IV is connected to the oil outlet end of the filter screen.

[0011] The brake valve assembly includes a solenoid directional valve III and a hydraulic directional valve. The oil inlet of the solenoid directional valve III is connected to the hydraulic pump through a check valve. The oil outlet of the solenoid directional valve III is connected to the oil inlet of the hydraulic directional valve and the pressure reducing valve II. The control end of the hydraulic directional valve is connected to the hydraulic pump. The output end of the hydraulic directional valve is connected to the control end of the dual-way brake valve.

[0012] The oil outlet of the dual-way brake valve and the oil outlet of the hydraulic retarder valve are connected together through shuttle valve II, and the oil outlet of shuttle valve II is connected to the oil inlet of shuttle valve III.

[0013] Furthermore, the hydraulic pump is a constant-pressure variable hydraulic pump.

[0014] It also includes a front axle brake accumulator and a rear axle brake accumulator, the oil inlet ends of which are connected to the hydraulic pump via check valves.

[0015] The oil outlet of the front axle brake accumulator is divided into two paths, which are respectively connected to the oil inlet of the dual-path brake valve and the filter element I; the oil outlet of the rear axle brake accumulator is divided into three paths, which are respectively connected to the oil inlet of the solenoid directional valve III, the dual-path brake valve and the hydraulic slack valve.

[0016] One path of the dual-path brake valve connects to the front axle brake accumulator and shuttle valve I, while the other path connects to the rear axle brake accumulator and shuttle valve II.

[0017] The inlet end of the front brake valve assembly is connected to the inlet end of the solenoid directional valve II. The solenoid directional valve I and the pressure reducing valve I are connected in parallel to the outlet end of the solenoid directional valve II. The outlet end of the front brake valve assembly is connected to the front axle dry brake.

[0018] The inlet of the rear brake valve is connected to the inlet of the pressure reducing valve II. The outlet of the pressure reducing valve II is connected to the filter screen and the parking piston chamber of the rear axle wet brake, respectively. The outlet of the filter screen is connected to the overflow valve and the rear brake proportional valve group, respectively.

[0019] The solenoid directional valve I is a two-position two-way solenoid directional valve, the solenoid directional valve II is a two-position three-way solenoid directional valve, the solenoid directional valve III is a two-position four-way solenoid directional valve, and the hydraulic control directional valve is a two-position four-way hydraulic control directional valve.

[0020] It includes two operating modes: manual driving and autonomous driving. The braking conditions in manual driving mode include manual service braking, manual parking braking, manual wet skid braking, manual emergency braking, and manual hydraulic easing braking. The braking conditions in autonomous driving mode include autonomous service braking, autonomous parking braking, manual wet skid braking, and manual emergency braking. In autonomous driving mode, the hydraulic pressure in emergency braking and parking braking modes is the same as in manual operation. Specific operations are as follows:

[0021] Manual driving vehicle braking: When electromagnetic directional valve III is energized, it operates in the right position; when electromagnetic directional valve II is de-energized, it operates in the left position. When the dual-way brake valve is depressed, electromagnetic directional valve I is de-energized and operates in the left position.

[0022] Manual driving parking brake: After pressing the parking button, the solenoid directional valve III must not work in the left position. The hydraulic directional valve moves to the right position under the action of the pressure in the right control chamber. The solenoid directional valve II is energized and works in the right position.

[0023] Manual driving wet and slippery braking: When the vehicle encounters a wet and slippery road surface, the solenoid directional valve II is de-energized and operates in the left position, while the solenoid directional valve III is energized and operates in the right position; when the dual-way brake valve is pressed, the solenoid directional valve I is energized.

[0024] Manual emergency braking: When the emergency brake button is pressed or the system loses power unexpectedly, all solenoid directional valves must not operate in the left position; the pressure on the right side of the hydraulic directional valve is greater than the spring force on the left side, so it operates in the right position;

[0025] Manual driving - hydraulic slow braking: When driving downhill, solenoid directional valve III is energized and operates in the right position, while solenoid directional valve II is de-energized and operates in the left position, and the hydraulic slow braking valve handle is pulled.

[0026] Unmanned driving - service braking: When electromagnetic directional valve III is energized, it operates in the right position; when electromagnetic directional valve II is de-energized, it operates in the left position. When wire control braking is required, relevant instructions are issued from the ground control center. The controller and communication components and other electronic control system equipment output current to proportional valve core I and proportional valve core II. At the same time, electromagnetic directional valve I is de-energized and operates in the left position.

[0027] Unmanned Driving - Wet and Slippery Braking: When braking is required during driving on wet and slippery roads in unmanned driving mode, the controller and communication components and other electronic control system equipment output current to proportional valve core I and proportional valve core II. Solenoid directional valve II is not energized to work in the left position, solenoid directional valve III is energized to work in the right position, and solenoid directional valve I is energized to work in the right position.

[0028] The present invention has the following advantages: The wire-controlled proportional unmanned driving braking system and its usage method for mining dump trucks of the present invention connects wire-controlled braking and manual operation braking in parallel. Regardless of which party issues the braking command, the vehicle can brake quickly, realizing the simultaneous realization of manual operation braking and wire-controlled remote braking functions; at the same time, it requires minimal changes to the original hydraulic system, is convenient for vehicle modification, and has low strength requirements. Attached Figure Description

[0029] The accompanying drawings, as part of this invention, are provided to further illustrate the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation thereof. Clearly, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0030] In the attached diagram:

[0031] Figure 1 This is the control principle diagram of the present invention;

[0032] Figure 2 This is a hydraulic schematic diagram of the present invention.

[0033] In the diagram: 1. Front axle dry brake; 2. Front brake valve assembly; 3. Solenoid directional valve I; 4. Pressure reducing valve I; 5. Solenoid directional valve II; 6. Front brake proportioning valve assembly; 7. Filter element I; 8. Proportional valve core I; 9. Relay valve I; 10. Shuttle valve I; 11. Rear brake valve; 12. Relief valve; 13. Damping; 14. Filter screen; 15. Pressure reducing valve II; 16. Rear axle wet brake; 17. Hydraulic retarder. 18. Shuttle valve II, 19. Dual-way brake valve, 20. Brake valve assembly, 21. Solenoid directional valve III, 22. Check valve, 23. Front axle brake accumulator, 24. Rear axle brake accumulator, 25. Hydraulic directional valve, 26. Proportional valve core II, 27. Shuttle valve III, 28. Shuttle valve IV, 29. Rear brake proportional valve assembly, 30. Relay valve II, 31. Filter element II, 32. Hydraulic pump, 33. Oil tank.

[0034] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0036] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0037] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0038] like Figures 1 to 2 The illustrated wire-controlled proportional unmanned braking system for a mining dump truck includes a hydraulic pump 32 connected to an oil tank 33. The hydraulic pump 32 is connected to a front braking system and a rear braking system via a brake valve assembly 20. The front braking system includes a dual-path brake valve 19, a front brake proportional valve assembly 6, a front brake valve assembly 2, and a front axle dry brake 1. The rear braking system includes a dual-path brake valve 19, a hydraulic retardation valve 17, a rear brake proportional valve assembly 29, a rear brake valve 11, and a rear axle wet brake 16. It also includes a front axle brake accumulator 23 and a rear axle brake accumulator 24. The front axle dry brake, the front brake valve assembly, and other components constitute the front braking circuit; the rear axle wet brake, the rear brake valve, and other components constitute the rear braking circuit. The hydraulic pump, the brake valve assembly, and the front and rear brake accumulators are responsible for providing and distributing pressure oil to the braking system. The dual-path brake valve and the hydraulic retardation valve provide an operation mode for manual braking; the front and rear brake proportional valve assemblies provide an operation mode for wire-controlled braking. The two are connected in parallel via a shuttle valve.

[0039] like Figures 1 to 2 The illustrated wire-controlled proportional unmanned braking system for a mining dump truck uses a constant-pressure variable-displacement hydraulic pump 32. This invention's hydraulic pump is a constant-pressure variable-displacement pump. When the dump truck does not require braking, the pump operates in a high-pressure, low-displacement standby state, requiring very little flow. When the dump truck brakes, the pump displacement increases and the pressure decreases, operating in a low-pressure, high-displacement state.

[0040] like Figures 1 to 2The illustrated wire-controlled proportional unmanned braking system for a mining dump truck has the front axle brake accumulator 23 and the rear axle brake accumulator 24 connected to the hydraulic pump 32 via check valves 22. The front axle brake accumulator 23 has two outlets connected to the inlets of a dual-path brake valve 19 and filter element I 7, respectively. The rear axle brake accumulator 24 has three outlets connected to the inlets of an electromagnetic directional valve III 21, a dual-path brake valve 19, and a hydraulic retarder valve 17, respectively. One path of the dual-path brake valve 19 connects to the front axle brake accumulator 23 and shuttle valve I 10, while the other path connects to the rear axle brake accumulator 24 and shuttle valve II 18.

[0041] like Figures 1 to 2 The illustrated wire-controlled proportional unmanned braking system for a mining dump truck includes a brake valve group 20 comprising an electromagnetic directional valve III 21 and a hydraulic directional valve 25. The inlet of the electromagnetic directional valve III 21 is connected to a hydraulic pump 32 via a check valve 22. The outlet of the electromagnetic directional valve III 21 is connected to the inlet of the hydraulic directional valve 25 and a pressure reducing valve II 15. The control end of the hydraulic directional valve 25 is connected to the hydraulic pump 32, and the output end of the hydraulic directional valve 25 is connected to the control end of a dual-path brake valve 19. The brake valve assembly 20 of the present invention is located at the center of the hydraulic system, connecting the front axle brake accumulator 23 and the rear axle brake accumulator 24, and providing a pressure oil source for the hydraulic retardation valve 17, the dual-way brake valve 19, the rear brake valve 11, and the front brake proportional valve assembly 6 and the rear brake proportional valve assembly 29; the internal hydraulic control directional valve 25 determines whether the dual-way brake valve 19 is operated by foot pedal action or automatically controlled by the brake valve assembly 20; the electromagnetic directional valve III 21 determines whether to output pressure to the rear brake pressure reducing valve II 15.

[0042] like Figures 1 to 2 The illustrated wire-controlled proportional unmanned braking system for a mining dump truck connects the oil outlet of the dual-way brake valve 19 and the oil outlet of the hydraulic retarder valve 17 via a shuttle valve II 18. The oil outlet of shuttle valve II 18 is connected to the oil inlet of shuttle valve III 27. The dual-way brake valve 19 is a neutral-position closed control valve, automatically controlled by foot pedal operation or pressure applied by the brake valve assembly 20, applying pressure to the forward and rear brake circuits. The hydraulic retarder valve 17 can be operated by a lever, outputting insufficient braking pressure to the rear brake hydraulic circuit to reduce vehicle speed.

[0043] like Figures 1 to 2The illustrated wire-controlled proportional unmanned braking system for a mining dump truck includes a front braking proportional valve group 6 comprising a filter element I7, a proportional valve core I8, a relay valve I9, and a shuttle valve I10. The front braking proportional valve group 6 has two oil inlet ends. One oil inlet end is connected to the oil inlet ends of the proportional valve core I8 and the relay valve I9 ​​respectively through the filter element I7. The oil outlet end of the proportional valve core I8 is connected to the control end of the relay valve I9. The oil outlet end of the relay valve I9 ​​is ​​connected to the other oil inlet end of the front braking proportional valve group 6 through the shuttle valve I10. The oil outlet end of the shuttle valve I10 is connected to the solenoid directional valve II5. The front brake proportional valve assembly 6 of this invention provides a drive-by-wire operation for the braking system. The proportional valve core I8 is controlled by drive-by, and the front axle brake accumulator 23 provides a pressure source for it. The pressure output by the proportional valve core I8 increases with the increase of current. Since the output flow of the proportional valve is relatively small, it cannot meet the requirements of rapid braking. In order to improve the braking response speed, a direct proportional graded braking rapid response technology is adopted. A high-flow-capacity relay valve I9 ​​is ​​selected as the pressure output device. The proportional valve core I8 acts as a control element, outputting control pressure to drive the valve core of the relay valve I9 ​​to move. The relay valve I9 ​​directly outputs the pressure in the front axle brake accumulator to the front axle dry brake 1 through the front brake valve assembly 2. The output braking pressure can be controlled according to the position of the valve core of the relay valve I9. The front brake proportional valve assembly 6 has a built-in shuttle valve I10. When there is braking pressure at either the dual-way brake valve 19 or the relay valve I9, the valve core of the shuttle valve I10 can be pushed to output pressure to the brake for braking.

[0044] like Figures 1 to 2 The illustrated wire-controlled proportional unmanned braking system for a mining dump truck includes a front brake valve assembly 2 comprising an electromagnetic directional valve I3, a pressure reducing valve I4, and an electromagnetic directional valve II5. The inlet of the front brake valve assembly 2 is connected to the inlet of the electromagnetic directional valve II5. The electromagnetic directional valve I3 and the pressure reducing valve I4 are connected in parallel to the outlet of the electromagnetic directional valve II5. The outlet of the front brake valve assembly 2 is connected to the front axle dry brake 1. The front brake valve assembly 2 of this invention provides pressurized hydraulic fluid to the front axle dry brake 1. When a halved braking force is required, the electromagnetic directional valve I3 is energized, and the hydraulic fluid pressure is reduced through the pressure reducing valve I4; conversely, the hydraulic system provides the full braking pressure.

[0045] like Figures 1 to 2The illustrated wire-controlled proportional unmanned braking system for a mining dump truck includes a rear brake valve 11 comprising an overflow valve 12, a damper 13, a filter 14, and a pressure reducing valve II 15. The inlet of the rear brake valve 11 is connected to the inlet of the pressure reducing valve II 15. The outlet of the pressure reducing valve II 15 is connected to the filter 14 and the parking piston chamber of the rear axle wet brake 16, respectively. The outlet of the filter 14 is connected to the overflow valve 12 and the rear brake proportional valve assembly 29, respectively. In the rear brake valve 11 of this invention, the hydraulic oil pressure decreases after passing through the pressure reducing valve II 15, at which point the pressure oil is divided into two paths: one path for hydraulic oil... The hydraulic oil flows to filter 14 and damper 13. When the pressure after damper 13 is less than the set pressure of relief valve 12, the hydraulic oil flows to shuttle valve IV 28 in rear brake proportional valve group 29. The pressure is delivered to the upper part of shuttle valve IV 28, causing the valve core to move down. The pressure is finally transmitted to the service piston chamber in rear axle wet brake 16 as back pressure, which improves the response speed when performing service braking. When the pressure is higher than the set pressure of relief valve 12, the oil returns to oil tank 33 and is cleaned by filter 14. Another pressure oil is directly delivered to the parking piston chamber in rear axle wet brake 16, which pushes open the spring device and finally releases the parking brake.

[0046] like Figures 1 to 2 The illustrated wire-controlled proportional unmanned braking system for a mining dump truck includes a rear brake proportional valve assembly 29 comprising a proportional valve core II 26, a shuttle valve III 27, a shuttle valve IV 28, a relay valve II 30, and a filter element II 31. The oil inlet of the filter element II 31 is connected to the oil inlet of the rear brake proportional valve assembly 29. The oil outlet of the filter element II 31 is connected to both the proportional valve core II 26 and the relay valve II 30. The oil outlet of the proportional valve core II 26 is connected to the control end of the relay valve II 30 via the shuttle valve III 27. The oil outlet of the relay valve II 30 is connected to the travel piston chamber of the rear axle wet brake 16 via the shuttle valve IV 28. The shuttle valve IV 28 is connected to the oil outlet of the filter screen 14. The rear brake proportional valve group 29 of the present invention functions similarly to the front brake proportional valve group 6. The pressure oil of the proportional valve core II 26 and the relay valve II 30 is provided by the rear brake accumulator 24. The proportional valve core II 26 simultaneously controls two relay valve cores, which provide pressure to the left and right rear axle wet brakes 16 respectively. A shuttle valve III is added between the proportional valve core II 26 and the relay valve II 30 to ensure that the control pressure output by the dual-path brake valve 19 or the hydraulic retarder valve 17 can also push the valve core of the relay valve II 30 to output braking pressure to the driving piston chamber of the rear brake. A shuttle valve IV 28 is placed after each of the two relay valves II 30 to ensure that the driving back pressure and the braking pressure output by the relay valve can reach the driving piston chamber in the rear axle wet brake 16.

[0047] like Figures 1 to 2The mining dump truck shown features a drive-by-wire proportional unmanned braking system. The front axle uses a dry disc brake with calipers. When braking is applied, pressurized oil acts on the piston face opposite the brake pads inside the brake caliper, clamping the brake disc by pressing the brake pads, thereby reducing wheel speed and achieving braking. The rear axle uses a wet brake, a fully enclosed multi-disc brake cooled by oil. Braking is achieved through spring force and hydraulic pressure. Service braking is achieved by pressurizing the service piston chamber; parking braking requires depressurizing the parking piston chamber. The parking brake is activated by the spring force of an internal mechanical spring device pressing the friction pads and disc, and the parking brake is released by pressurizing the parking piston chamber to release the spring force.

[0048] like Figures 1 to 2 The shown is a wire-controlled proportional unmanned braking system for a mining dump truck. The electromagnetic directional valve I3 is a two-position two-way electromagnetic directional valve, the electromagnetic directional valve II5 is a two-position three-way electromagnetic directional valve, the electromagnetic directional valve III21 is a two-position four-way electromagnetic directional valve, and the hydraulic control directional valve 25 is a two-position four-way hydraulic control directional valve.

[0049] The operation method of the wire-controlled proportional unmanned braking system for mining dump trucks includes two modes: manual driving and unmanned driving. The braking conditions in manual driving mode include manual service braking, manual parking braking, manual wet skid braking, manual emergency braking, and manual hydraulic slow braking. The braking conditions in unmanned driving mode include unmanned service braking, unmanned parking braking, manual wet skid braking, and manual emergency braking. In unmanned driving, the hydraulic pressure in emergency braking and parking braking modes is the same as in manual operation. Specific operations are as follows:

[0050] Manual driving

[0051] When braking is performed manually, the current value of the proportional valve cores I8 and II26 of the front and rear brake proportional valves is 0, and the front and rear brake proportional valve cores do not participate in the operation of the hydraulic circuit. When braking is performed, the system flow increases, and the hydraulic pump 32 will continuously replenish the pressure oil to the front axle brake accumulator 23 and the rear axle brake accumulator 24 until the state stabilizes.

[0052] Normal driving conditions

[0053] During normal driving, the parking position needs to be released. Since it's not necessary to depress the dual-way brake valve 19 or pull the hydraulic retarder valve 17 lever during normal driving, and there is no pressure in the upper pressure control chambers of relay valve I9 ​​and relay valve II30, the lower working output pressure of the relay valve core is 0. That is, the pressure on the left side of shuttle valve I10 and the lower side of shuttle valve IV28 is 0. At this time, the solenoid directional valve III21 is energized, pushing the valve core to the left and placing it in the right position. The rear brake accumulator 24 provides pressurized oil, which is then delivered by the solenoid directional valve III21 to the rear brake valve 11. The pressure is reduced by the pressure reducing valve II15, and the pressurized oil is then delivered to the driving piston chamber of the rear axle wet brake 16 as back pressure, and to the parking piston chamber of the rear axle wet brake 16, ultimately releasing the parking position by pushing open the spring device. The solenoid directional valve II5 is not energized, therefore there is no braking pressure in the front brake valve group 2, the front brake proportional valve group 6, and the front axle dry brake 1.

[0054] Manual driving - service brake

[0055] When electromagnetic directional valve III21 is energized, it operates in the right position. The hydraulic pressure in the rear axle parking piston chamber pushes open the spring device to release the parking brake. When electromagnetic directional valve II5 is de-energized, it operates in the left position. The oil inlet of the front brake valve assembly 2 is connected to the dual-way brake valve 19 through shuttle valve I10. When the dual-way brake valve 19 is depressed, the pressure in the front and rear axle brake accumulators 23 and 24 is transferred to the front and rear brake circuits respectively. The hydraulic pump 32 changes from a high-pressure, low-displacement standby state to a low-pressure, high-displacement state to replenish oil to the accumulators 23 and 24. In the front brake circuit, the hydraulic fluid pushes the valve core of shuttle valve I10 to the left, entering the oil inlet port of the front brake valve assembly 2. When electromagnetic directional valve I3 is de-energized, it operates in the left position. The pressurized oil directly enters the front axle dry brake 1 through the check valve in electromagnetic directional valve I3 to provide full braking force. In the rear braking circuit, the solenoid directional valve Ⅲ21 is energized and operates in the right position, releasing the parking brake. Since the hydraulic retardation valve 17 and the proportional valve core Ⅱ26 do not output pressure, the pressure oil output by the dual-way brake valve 19 sequentially pushes the valve core of shuttle valve Ⅱ18 to the right and the valve core of shuttle valve Ⅲ27 to the left to establish pressure in the control oil chamber on the upper side of relay valve Ⅱ30. The relay valve core moves down and outputs the service braking pressure to the lower part of shuttle valve Ⅳ28. At this time, the service braking pressure at the lower part of shuttle valve Ⅳ28 is much higher than the service back pressure at the upper part of shuttle valve. The valve core of shuttle valve Ⅳ28 moves up, and finally the service braking pressure will be input to the service piston chamber of the rear axle wet brake 16 for braking.

[0056] Manual driving - parking brake;

[0057] After pressing the parking button, the solenoid directional valve III 21 is de-energized and operates in the left position. The parking piston chamber of the rear axle wet brake 16 is directly connected to the hydraulic oil tank 33, thus cutting off the oil inlet. There is no pressure in the oil in the parking piston chamber, so the spring device applies spring force to the parking brake for braking. The hydraulic directional valve 25 moves to the left and operates in the right position under the action of the pressure in the right control chamber. At this time, the pressure in the rear brake accumulator 24 enters the dual-way brake valve 19 through the solenoid directional valve III 21 and the hydraulic directional valve 25, and automatically applies braking force to the front and rear hydraulic brake circuits. In the front brake hydraulic circuit, the solenoid directional valve II 5 is energized and pushes the valve core to move to the right position, cutting off the oil inlet. The front brake valve group 2 is directly connected to the hydraulic oil tank 33. The valve core of the shuttle valve I 10 moves to the left, and the oil pressure stops before the oil inlet of the solenoid directional valve II 5, while there is no pressure in the front axle dry brake 1. In the rear braking circuit, the pressure oil output by the dual-way brake valve 19 also sequentially pushes the valve core of shuttle valve II 18 to the right and the valve core of shuttle valve III 27 to the left to establish pressure in the control oil chamber on the upper side of relay valve II 30. The relay valve core works in the upper position and inputs the pressure in the rear axle brake accumulator 24 into the driving piston chamber of the rear axle wet brake 16 through the shuttle valve IV 28 with the valve core moving upward to apply pressure.

[0058] Manual driving - wet braking

[0059] When the vehicle encounters a slippery road surface, the braking force applied by the front axle dry brake 1 is halved, while the rear axle wet brake 16 provides the full braking force. The solenoid directional valve II 5 is not energized to the left position, and the solenoid directional valve III 21 is energized to the right position. When the dual-way brake valve 19 is depressed, the rear brake circuit is synchronized with the service brake. The rear brake accumulator 24 provides hydraulic pressure, which is output to the parking piston chamber via the solenoid directional valve III 21 and the pressure reducing valve II 15, releasing the parking brake by pushing open the spring device. The dual-way brake valve 19 outputs the pressure from the rear brake accumulator 24 through the shuttle valve II 18 and the shuttle valve III 27 to the upper control oil chamber of the relay valve II 30, establishing pressure and pushing the valve core of the relay valve II 30 downwards. Finally, the passage between the rear brake accumulator 24 and the rear brake service piston chamber is opened, establishing braking pressure in the rear brake service piston chamber. In the front braking circuit, the solenoid directional valve I3 is energized by electronic control to push the valve core to the left. The pressure oil that originally passed through the valve core is cut off by the check valve, and the oil is diverted to the pressure reducing valve I4. Under the action of the pressure reducing valve, the pressure is halved and delivered to the front axle dry brake 1.

[0060] Manual driving - emergency braking;

[0061] When the emergency brake button is pressed or the system experiences an unexpected power failure, all solenoid directional valves must not operate in the left-hand position. Pressure exists in the right-hand cavity of the hydraulic directional valve 25, causing the valve core to operate in the right-hand position, opening the passage between the brake valve assembly 20 and the dual-way brake valve 19. At this time, the pressure in the rear brake accumulator 24 enters the dual-way brake valve 19 via the solenoid directional valve III 21 and the hydraulic directional valve 25, automatically applying braking force to the front and rear hydraulic braking circuits. In the front axle braking circuit, the valve core of shuttle valve I 10 moves to the left, so the solenoid directional valve II 5 must not operate in the left-hand position. The pressurized oil provided by the dual-way brake valve 19 flows through shuttle valve I 10, solenoid directional valve II 5, and solenoid directional valve I 3 to apply full braking pressure to the front brake. In the rear axle braking circuit, the valve core of shuttle valve II 18 moves to the right, and the valve core of shuttle valve III 27 moves to the left. The pressurized oil output from the dual-way brake valve 19 also passes through shuttle valve II 18 and shuttle valve III 27 to the upper control oil chamber of relay valve II 30 and establishes pressure. The control pressure push valve II 30 moves downward, causing the pressure output from the rear axle brake accumulator 24 in the brake valve assembly 20 to force the valve core of shuttle valve IV 28 to move upward. Pressurized oil is then input through shuttle valve IV 28 to the driving piston chamber of the rear axle wet brake 16 to apply pressure. Since the pressurized oil in the parking piston chamber of the rear axle wet brake 16 flows directly to the oil tank 33 via the left position of the solenoid directional valve III 21 and has no pressure, the rear brake automatically locks. At this point, all braking devices of the front and rear brakes are fully locked, reducing the vehicle speed to zero and stopping the vehicle in place as quickly as possible.

[0062] Manual driving - hydraulic easing braking

[0063] When traveling downhill, it is often necessary to apply partial braking force to the travel piston chamber of the rear axle wet brake 16 to reduce vehicle speed and achieve a slowing effect. This braking effect is achieved by pulling the handle of the hydraulic slowing valve 17. During driving, the solenoid directional valve III 21 is energized and operates in the right position, while the solenoid directional valve II 5 is de-energized and operates in the left position. The hydraulic system operation status can be found in the "Normal Driving State" section above. At this time, pulling the handle of the hydraulic slowing valve 17 outputs the oil in the rear axle brake accumulator 24; the valve core of shuttle valve II 18 moves to the left, and the valve core of shuttle valve III 27 moves to the left. The pressurized oil is output through shuttle valve II 18 and shuttle valve III 27 to the upper control chamber of relay valve II 30 and builds pressure, pushing relay valve II 30 down; the pressurized oil in the rear brake accumulator 24 moves the valve core of shuttle valve IV 28 up through relay valve II 30, and finally inputs into the travel piston chamber of the rear axle wet brake 16. At this time, there is no braking pressure in the front axle dry brake 1, and the pressure output from the hydraulic retardation valve 17 to the rear brake 16 is relatively small, so the vehicle will brake and slow down to slowly pass through the downhill slope.

[0064] unmanned

[0065] In normal driving mode without braking, the brake hydraulic system operates identically to that in manual driving, as described in the "Normal Driving State" section above. To provide brake-by-wire functionality while retaining manual control, a brake-by-wire system needs to be connected in parallel with the existing manual control components such as the pedal valve and retarder handle. The opening degree of the electro-hydraulic proportional valve core is controlled by the electronic control system, adjusting the output pressure of relay valves I9 and II30, which are then transmitted to the front and rear brake discs. A shuttle valve is used to connect the manual braking via the pedal valve and the brake-by-wire system in parallel. Proportional valve cores I8 and II26 are directly proportional, with the output control pressure increasing with the current value. Before using the autonomous driving function, the required current values ​​for proportional valve cores I8 and II26 need to be verified and calculated. Ultimately, the braking force of the front and rear brakes in autonomous driving mode is the same as in manual driving mode. In autonomous driving mode, the hydraulic retarder valve 17 does not output braking pressure, and the dual-way brake valve 19 does not output pressure when the electromagnetic directional valve III21 is energized in the right position. The following is a detailed explanation of the various braking states during driverless operation:

[0066] Unmanned driving - service brake

[0067] When electromagnetic directional valve III21 is energized, it operates in the right position. Oil in the rear brake accumulator 24 is transported through electromagnetic directional valve III21 and pressure reducing valve II15 to the parking piston chamber of the rear axle wet brake 16, disengaging the mechanical spring device and releasing the parking brake. When electromagnetic directional valve II5 is de-energized, it operates in the left position, opening the oil inlet of the front brake valve assembly 2. There is no pressure on the right side of the valve cores of shuttle valves I10 and III27. When wire-controlled braking is required, relevant commands are issued from the ground control center. The controller and communication components, along with other electrical control system equipment, output current to the front and rear proportional valve cores I8 and II26. The front and rear brake accumulators 23 and 24 provide pressure oil sources to proportional valve cores I8 and II26, respectively. The path from the proportional valve pressure output port to the oil tank is blocked, while the path to the accumulator oil source is opened. The proportional valve cores directly or using the rightward movement of shuttle valve III27 output pressure to establish control pressure in the upper pressure control chambers of relay valves I9 and II30, respectively. Under the control pressure from the upper side, the relay valve core moves downward to the upper position, opening the passages connecting the front brake accumulator 23 to the left side of shuttle valve I10 and the rear brake accumulator 24 to the lower side of shuttle valve IV28. This pushes the valve cores of shuttle valve I10 and shuttle valve IV28 to the right and upward, respectively. In the front brake circuit, the solenoid directional valves II5 and I3 do not operate with their valve cores in the left position. The output pressure of relay valve I9, through shuttle valve I10, solenoid directional valve II5, and solenoid directional valve I3, finally reaches the front axle dry brake 1 to establish pressure for braking. In the rear brake circuit, the output braking pressure of relay valve II30 reaches the lower part of shuttle valve III27. The braking pressure is greater than the travel back pressure at the upper part of the shuttle valve, pushing the shuttle valve core upward, ultimately establishing pressure in the travel piston chamber of the rear brake 16 for braking.

[0068] Unmanned driving - wet braking

[0069] When braking is required on slippery surfaces in autonomous driving mode, the braking force applied by the front axle dry brake 1 is still halved, while the rear axle wet brake 16 provides sufficient braking force. During braking, the controller and communication components and other electronic control system equipment output current to the front and rear proportional valve cores I8 and II26, respectively. The solenoid directional valve II5 is not energized to the left position, while the solenoid directional valve III21 is energized to the right position. At this time, the rear braking circuit is consistent with the service braking circuit, as described in "Autonomous Driving - Service Braking" above. The pressure in the front braking circuit is still output by the relay valve I9, and the upper control pressure of the relay valve is provided by the proportional valve 9, as described in "Autonomous Driving - Service Braking" above. At this time, the solenoid directional valve I3 is energized to the right position, and the pressure oil that originally passed through the valve core is cut off by the check valve. The oil is diverted to the pressure reducing valve I4, and under the action of the pressure reducing valve I4, the pressure is halved and delivered to the front axle dry brake 1.

[0070] In autonomous driving, the hydraulic state of emergency braking mode and parking braking mode is the same as that of manual operation. The eight proportional valve cores I and II26 do not output pressure. The logic control is achieved by energizing the electromagnetic directional valve II5 and the electromagnetic directional valve III21. Please refer to the manual driving section above.

[0071] This invention relates to a wire-controlled proportional unmanned braking system and its usage method for mining dump trucks. Based on the existing hydraulic braking system, it adds front and rear proportional brake valves in parallel. The electronic control system controls the output pressure of the proportional brake valve group, which is then transmitted to the front and rear brake discs. A shuttle valve is used to connect manual braking via pedal valves and wire-controlled braking in parallel. Under manual operation, pressurized oil from the brake valves is supplied to the pedal valves. By pressing the pedal valves, the pressurized oil is transmitted to the front and rear brake valves, ultimately establishing pressure on the front and rear brake discs. The parking pressure is directly provided by the brake valves. The brake valve group delivers oil to the rear brake valve group, which adjusts the pressure to the required level and transmits it to the rear brake disc release spring device, ultimately releasing the parking brake. For the wire-controlled unmanned mining truck braking scheme, front and rear electro-hydraulic proportional brake valve groups are added as core components of the wire-controlled proportional braking technology. After the ground control center issues relevant commands, the controller and communication components, among other electronic control system equipment, can control the output pressure of the proportional brake valve group, outputting corresponding pressure to the brakes to activate and deactivate the vehicle's service and parking brake functions. The system combines brake-by-wire and manual braking in parallel, allowing the vehicle to brake quickly regardless of which brake command is issued, achieving both manual and remote brake-by-wire functions simultaneously. The unmanned steering system reduces driver workload and improves productivity. Emergency braking is provided simultaneously with system power failure, ensuring vehicle safety. It requires minimal modification to the existing hydraulic system, facilitating vehicle retrofitting and reducing structural stress. The system employs graded braking with rapid response technology, resulting in fast and sensitive braking action.

[0072] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0073] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features found in other embodiments but not others, combinations of features from different embodiments are also within the scope of protection of this invention and form different embodiments. For example, in the embodiments described above, those skilled in the art can use them in combination based on known technical solutions and the technical problems to be solved by this application.

[0074] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A wire-controlled proportional unmanned braking system for mining dump trucks, characterized in that: Includes a hydraulic pump (32) connected to an oil tank (33), the hydraulic pump (32) being connected to a front braking system and a rear braking system via a brake valve assembly (20); The front braking system includes a dual-way brake valve (19), a front brake proportional valve group (6), a front brake valve group (2), and a front axle dry brake (1). The front brake valve assembly (2) includes a solenoid directional valve I (3), a pressure reducing valve I (4), and a solenoid directional valve II (5). The front brake proportional valve group (6) includes filter element I (7), proportional valve core I (8), relay valve I (9) and shuttle valve I (10). The front brake proportional valve group (6) has two oil inlet ends. One oil inlet end is connected to the oil inlet ends of proportional valve core I (8) and relay valve I (9) respectively through filter element I (7). The oil outlet end of proportional valve core I (8) is connected to the control end of relay valve I (9). The oil outlet end of relay valve I (9) is connected to the other oil inlet end of the front brake proportional valve group (6) through shuttle valve I (10). The oil outlet end of shuttle valve I (10) is connected to solenoid directional valve II (5). The rear braking system includes a dual-path brake valve (19), a hydraulic retardation valve (17), a rear brake proportioning valve group (29), a rear brake valve (11), and a rear axle wet brake (16). The rear brake valve (11) includes an overflow valve (12), a damper (13), a filter (14), and a pressure reducing valve II (15). The rear brake proportional valve assembly (29) includes a proportional valve core II (26), a shuttle valve III (27), a shuttle valve IV (28), a relay valve II (30), and a filter element II (31). The oil inlet end of the filter element II (31) is connected to the oil inlet end of the rear brake proportional valve assembly (29). The oil outlet end of the filter element II (31) is connected to the oil inlet ends of the proportional valve core II (26) and the relay valve II (30), respectively. The oil outlet end of the proportional valve core II (26) is connected to the control end of the relay valve II (30) through the shuttle valve III (27). The oil outlet end of the relay valve II (30) is connected to the driving piston chamber of the rear axle wet brake (16) through the shuttle valve IV (28). The shuttle valve IV (28) is connected to the oil outlet end of the filter screen (14). The brake valve assembly (20) includes a solenoid directional valve III (21) and a hydraulic directional valve (25). The oil inlet of the solenoid directional valve III (21) is connected to the hydraulic pump (32) through a check valve (22). The oil outlet of the solenoid directional valve III (21) is connected to the oil inlet of the hydraulic directional valve (25) and the pressure reducing valve II (15). The control end of the hydraulic directional valve (25) is connected to the hydraulic pump (32). The output end of the hydraulic directional valve (25) is connected to the control end of the dual-way brake valve (19). The oil outlet of the dual-way brake valve (19) and the oil outlet of the hydraulic slow valve (17) are connected together by shuttle valve II (18), and the oil outlet of shuttle valve II (18) is connected to the oil inlet of shuttle valve III (27). It also includes electronic control system equipment, including controllers and communication components, to control the output pressure of the front brake proportional valve group and the rear brake proportional valve group.

2. The wire-controlled proportional unmanned braking system for mining dump trucks as described in claim 1, characterized in that: The hydraulic pump (32) is a constant pressure variable hydraulic pump.

3. The wire-controlled proportional unmanned braking system for mining dump trucks as described in claim 1, characterized in that: It also includes a front axle brake accumulator (23) and a rear axle brake accumulator (24), the oil inlet ends of which are connected to a hydraulic pump (32) via a check valve (22).

4. The wire-controlled proportional unmanned braking system for mining dump trucks as described in claim 3, characterized in that: The oil outlet of the front axle brake accumulator (23) is divided into two paths, which are respectively connected to the oil inlet of the dual-path brake valve (19) and the filter element I (7); the oil outlet of the rear axle brake accumulator (24) is divided into three paths, which are respectively connected to the oil inlet of the electromagnetic reversing valve III (21), the dual-path brake valve (19) and the hydraulic slack valve (17).

5. The wire-controlled proportional unmanned braking system for mining dump trucks as described in claim 2, characterized in that: One path of the dual-path brake valve (19) is connected to the front axle brake accumulator (23) and shuttle valve I (10), and the other path of the dual-path brake valve (19) is connected to the rear axle brake accumulator (24) and shuttle valve II (18).

6. The wire-controlled proportional unmanned braking system for mining dump trucks as described in claim 1, characterized in that: The oil inlet of the front brake valve assembly (2) is connected to the oil inlet of the solenoid directional valve II (5). The solenoid directional valve I (3) and the pressure reducing valve I (4) are connected in parallel to the oil outlet of the solenoid directional valve II (5). The oil outlet of the front brake valve assembly (2) is connected to the front axle dry brake (1).

7. The wire-controlled proportional unmanned braking system for mining dump trucks as described in claim 1, characterized in that: The inlet of the rear brake valve (11) is connected to the inlet of the pressure reducing valve II (15). The outlet of the pressure reducing valve II (15) is connected to the filter screen (14) and the parking piston chamber of the rear axle wet brake (16), respectively. The outlet of the filter screen (14) is connected to the overflow valve (12) and the rear brake proportional valve group (29), respectively.

8. The wire-controlled proportional unmanned braking system for mining dump trucks as described in claim 1, characterized in that: The solenoid directional valve I (3) is a two-position two-way solenoid directional valve, the solenoid directional valve II (5) is a two-position three-way solenoid directional valve, the solenoid directional valve III (21) is a two-position four-way solenoid directional valve, and the hydraulic control directional valve (25) is a two-position four-way hydraulic control directional valve.

9. A method for using a wire-controlled proportional unmanned braking system for mining dump trucks, applicable to the wire-controlled proportional unmanned braking system for mining dump trucks as described in any one of claims 1-8, characterized in that: It includes two operating modes: manual driving and autonomous driving. The braking conditions in manual driving mode include manual service braking, manual parking braking, manual wet skid braking, manual emergency braking, and manual hydraulic easing braking. The braking conditions in autonomous driving mode include autonomous service braking, autonomous parking braking, manual wet skid braking, and manual emergency braking. In autonomous driving mode, the hydraulic pressure in emergency braking and parking braking modes is the same as in manual operation. Specific operations are as follows: Manual driving vehicle braking: When the electromagnetic reversing valve III (21) is energized, it operates in the right position; when the electromagnetic reversing valve II (5) is de-energized, it operates in the left position. When the dual-way brake valve (19) is pressed, the electromagnetic reversing valve I (3) is de-energized and operates in the left position. Manual driving parking brake: After pressing the parking button, the electromagnetic reversing valve III (21) must not work in the left position, the hydraulic reversing valve (25) moves to the right position under the action of the pressure of the right control chamber, and the electromagnetic reversing valve II (5) is energized and works in the right position. Manual driving wet and slippery braking: When the vehicle is in a wet and slippery road condition, the electromagnetic reversing valve II (5) is not energized to work in the left position, and the electromagnetic reversing valve III (21) is energized to work in the right position; when the dual-way brake valve (19) is pressed, the electromagnetic reversing valve I (3) is energized; Manual driving emergency braking: When the emergency brake button is pressed or the system loses power unexpectedly, all solenoid directional valves must not be powered to the left position; the hydraulic directional valve (25) operates in the right position when the pressure on the right side is greater than the spring force on the left side. Manual driving - hydraulic slow braking: When in downhill driving condition, the electromagnetic reversing valve Ⅲ (21) is energized and works in the right position, and the electromagnetic reversing valve Ⅱ (5) is not energized and works in the left position. Pull the handle of the hydraulic slow braking valve (17). Unmanned driving - vehicle braking: When the electromagnetic reversing valve III (21) is energized, it operates in the right position. When the electromagnetic reversing valve II (5) is not energized, it operates in the left position. When the wire control braking is required, the relevant instructions are issued at the ground control center. The electrical control system equipment outputs current to the proportional valve core I (8) and the proportional valve core II (26). At the same time, the electromagnetic reversing valve I (3) is not energized and operates in the left position. Unmanned driving - wet and slippery braking: When braking is required during driving on wet and slippery roads in unmanned driving mode, the electronic control system equipment outputs current to proportional valve core I (8) and proportional valve core II (26) during braking. Electromagnetic directional valve II (5) is not energized to the left position, electromagnetic directional valve III (21) is energized to the right position, and electromagnetic directional valve I (3) is energized to the right position.

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