A wet disc brake hydraulic system for a mining dump truck

Abstract

A mine dump truck wet disc brake hydraulic system, including main control valve, one end of main control valve is connected pressure oil source, the other end is connected front brake system and middle and rear brake system, front brake system includes brake pedal, front axle proportional control valve group, front axle brake valve group and front brake cylinder, middle and rear brake system includes brake pedal, slow running valve, middle and rear axle brake valve, rear axle proportional valve group, relay valve group, rear axle brake cylinder and middle axle brake cylinder, the utility model discloses a mine dump truck wet disc brake hydraulic system can realize manual operation brake and line control remote brake function, reaches unmanned operation's requirement, is used for unmanned vehicle or auxiliary driving, and in order to adapt to the distance of middle and rear axle of three axle vehicle and the distance of main brake valve group is longer, two relay valve groups are added, brake corresponding speed is improved, faster brake response is realized, makes travel more safe.

Description

Technical Field

[0001] This utility model relates to the field of engineering machinery technology, specifically a wet disc brake hydraulic system for mining dump trucks. Background Technology

[0002] As core equipment in mine transportation, mining dump trucks require braking systems that maintain reliability and durability under extreme conditions such as heavy loads, long slopes, and dusty environments. Traditional braking technologies suffer from the following drawbacks: reliance on pneumatic signals to transmit braking force results in response delays, leading to uncontrollable braking distances on downhill sections; uneven braking pressure distribution between the middle and rear axles of multi-axle vehicles can easily cause tire wear; single-channel mechanical control cannot meet the electronic control requirements of unmanned driving modes; and the lack of pressure compensation in the braking hydraulic circuits of the middle and rear axles of long-spacing mining trucks results in long braking delays and a risk of vehicle pitching loss of control. Therefore, as the tonnage of three-axle mining dump trucks in the market increases, traditional air braking systems can no longer meet the demands, and wet disc brakes are gradually being accepted as a better option. Meanwhile, unmanned mining trucks are another rapidly developing market trend, and control systems need to adapt to these trends. Summary of the Invention

[0003] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a simple and effective wet disc brake hydraulic system for mining dump trucks.

[0004] This utility model is achieved by the following technical solution: a wet disc brake hydraulic system for a mining dump truck, including a main control valve, one end of which is connected to a pressure oil source, and the other end of which is connected to a front braking system and a middle and rear braking system;

[0005] The front braking system includes a brake pedal, a front axle proportional control valve group, a front axle brake valve group, and a front brake cylinder.

[0006] The inlet of the brake pedal is connected to a pressurized oil source, and one outlet of the brake pedal is connected to the front axle proportional control valve assembly.

[0007] The front axle proportional control valve assembly includes a proportional valve core I and a shuttle valve II; the oil inlet of the proportional valve core I is connected to a pressure oil source, the two ends of the shuttle valve II are respectively connected to the proportional valve core I and the brake pedal, and the oil outlet of the shuttle valve II is connected to the oil inlet of the front axle brake valve assembly.

[0008] The front axle brake valve assembly includes a solenoid directional valve II, a pressure reducing valve I, and a solenoid directional valve III, and the oil outlet of the front axle brake valve assembly is connected to the front brake cylinder.

[0009] The middle and rear braking system includes a brake pedal, a retardation valve, middle and rear axle brake valves, a rear axle proportional valve group, a relay valve group, a rear axle brake cylinder, and a middle axle brake cylinder.

[0010] A shuttle valve I is provided between the brake pedal and the retardation valve, and the output end of the shuttle valve I is connected to the rear axle proportional valve group.

[0011] The middle and rear axle brake valve includes an overflow valve and a pressure reducing valve II; the input end of the middle and rear axle brake valve is connected to the main control valve, and the output end of the middle and rear axle brake valve is connected to the rear axle proportional valve group, the relay valve group, the rear axle brake cylinder, and the middle axle brake cylinder.

[0012] The rear axle proportional valve group includes a proportional valve core II, a shuttle valve III, a relay valve I, and a shuttle valve IV. The relay valve group includes a relay valve II and a shuttle valve V. After the pressure oil source enters the rear axle proportional valve group, one path is delivered as power oil to the relay valve I, and the other path is delivered as control oil to the proportional valve core II. The output end of the proportional valve core II is connected to the shuttle valve III. The other end of the shuttle valve III is connected to the shuttle valve I. The output end of the shuttle valve III is connected to the control ends of the relay valve I and the relay valve II. The oil outlet end of the relay valve I is connected to the travel piston chamber of the rear axle brake cylinder through the shuttle valve IV. The oil outlet end of the relay valve II is connected to the travel piston chamber of the middle axle brake cylinder through the shuttle valve V. The other ends of the shuttle valve IV and the other ends of the shuttle valve V are connected to the output ends of the middle and rear axle brake valves.

[0013] The main control valve includes a solenoid directional valve I, a hydraulic directional valve, a front axle brake accumulator, and a middle and rear axle brake accumulator. The inlet of the solenoid directional valve I is connected to a pressure oil source, the outlet of the solenoid directional valve I is connected to the inlet of the hydraulic directional valve and the middle and rear axle brake valve, the control end of the hydraulic directional valve is connected to the pressure oil source, and the output end of the hydraulic directional valve is connected to the control end of the brake pedal.

[0014] Furthermore, it also includes a front axle brake accumulator and a middle and rear axle brake accumulator, wherein the oil inlet ends of the front axle brake accumulator and the middle and rear axle brake accumulator are respectively connected to a pressure oil source through a one-way valve.

[0015] The oil outlet of the front axle brake accumulator is connected to the front braking system; the oil outlet of the middle and rear axle brake accumulators is divided into two paths, one of which is connected to the rear braking system and the other of which is connected to the solenoid directional valve I.

[0016] The oil inlet of the solenoid directional valve II is connected to the oil inlet of the front axle brake valve assembly, and the solenoid directional valve III and the pressure reducing valve I are connected in parallel at the oil outlet of the solenoid directional valve II.

[0017] The oil inlet of the middle and rear axle brake valve is divided into two paths after passing through pressure reducing valve II. One path connects to the rear axle brake cylinder and the middle axle brake cylinder, while the other path, after passing through damping, connects to shuttle valve IV and shuttle valve V.

[0018] The solenoid directional valve II is a two-position two-way solenoid directional valve, the solenoid directional valve III is a two-position three-way solenoid directional valve, the solenoid directional valve I 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.

[0019] The oil inlet ends of the front axle proportional control valve group, the rear axle proportional valve group, and the relay valve group are all equipped with filter elements.

[0020] This utility model has the following advantages: The wet disc brake hydraulic system of this utility model for mining dump truck can realize manual operation braking and remote control braking functions, meet the requirements of unmanned operation, and be used for unmanned vehicles or assisted driving. At the same time, in order to adapt to the long distance between the rear axle and the main brake valve group in the three-axle vehicle, two sets of relay valve groups are added to improve the braking response speed, achieve faster braking response, and make driving safer. Attached Figure Description

[0021] The accompanying drawings, as part of this utility model, are used to provide a further understanding of the present utility model. The illustrative embodiments and descriptions of the present utility model are used to explain the present utility model, but do not constitute an undue limitation of the present utility model. Obviously, the drawings described below are merely some embodiments; those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0022] In the attached diagram:

[0023] Figure 1 This is a hydraulic schematic diagram of this utility model.

[0024] In the diagram: 1. Main brake valve; 11. Solenoid directional valve I; 12. Hydraulic directional valve; 13. Front axle brake accumulator; 14. Middle and rear axle brake accumulators; 2. Brake pedal; 3. Front axle proportional control valve assembly; 31. Proportional valve core I; 32. Shuttle valve II; 4. Front axle brake valve assembly; 41. Solenoid directional valve II; 42. Pressure reducing valve I; 43. Solenoid directional valve III; 5. Front brake cylinder; 6. Middle and rear axle brake valves; 61. Pressure reducing valve II; 62. Relief valve; 7. Relay valve assembly; 71. Relay valve II; 72. Shuttle valve V; 8. Rear axle brake cylinder; 9. Rear axle proportional valve assembly; 91. Proportional valve core II; 92. Shuttle valve III; 93. Relay valve I; 94. Shuttle valve IV; 10. Rescheduling valve; 15. Middle axle brake cylinder; 16. Shuttle valve I.

[0025] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the present invention in any way, but rather to illustrate the concept of the present invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this utility model 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 this utility model, but are not intended to limit the scope of this utility model.

[0027] In the description of this utility model, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", and "outer" 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 utility model 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 limitations on this utility model.

[0028] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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 utility model based on the specific circumstances.

[0029] like Figure 1 The hydraulic wet disc brake system of a mining dump truck shown includes a main control valve 1, one end of which is connected to a pressure oil source, and the other end of which is connected to a front braking system and a middle and rear braking system. The front braking system includes a brake pedal 2, a front axle proportional control valve group 3, a front axle brake valve group 4, and a front brake cylinder 5. The middle and rear braking system includes a brake pedal 2, a retarder valve 10, a middle and rear axle brake valve 6, a rear axle proportional valve group 9, a relay valve group 7, a rear axle brake cylinder 8, and a middle axle brake cylinder 15. It also includes a front axle brake accumulator 13 and a rear axle brake accumulator 14, the oil inlets of which are respectively connected to the pressure oil source through check valves. In the wet disc brake hydraulic system of the mining dump truck of this utility model, the front brake cylinder, the front axle brake valve group and other components constitute the front brake circuit; the rear axle brake cylinder, the middle and rear axle brake valves and other components constitute the rear brake circuit; the main brake valve and the front and rear brake accumulators are responsible for providing and distributing the pressure oil source to the braking system; the brake pedal and the retarder valve provide the operation mode for manual braking; the front axle proportional valve group and the middle and rear axle proportional valve group provide the operation mode for brake-by-wire, and the two are connected in parallel through a shuttle valve.

[0030] like Figure 1The diagram illustrates a wet disc brake hydraulic system for a mining dump truck. The front axle brake accumulator 13 has its outlet connected to the front braking system. The middle and rear axle brake accumulator 14 has two outlets: one connected to the rear braking system, and the other connected to the solenoid directional valve I 11. The front axle brake accumulator provides hydraulic oil to the front braking system and mainly includes a brake pedal, a front axle proportional control valve group, a front axle brake valve group, and a front brake cylinder. The middle and rear axle brake accumulators provide hydraulic oil to the middle and rear axle braking systems and the main control valve, and include a brake pedal, a retardation valve, middle and rear axle brake valves, a rear axle proportional valve group, a relay valve group, a rear axle brake cylinder, a middle axle brake cylinder, and the solenoid directional valve I.

[0031] like Figure 1 The hydraulic system for wet disc braking of a mining dump truck is shown. The main control valve 1 includes an electromagnetic directional valve I 11, a hydraulically controlled directional valve 12, a front axle brake accumulator 13, and a middle and rear axle brake accumulator 14. The inlet of the electromagnetic directional valve I 11 is connected to a pressure oil source, and the outlet of the electromagnetic directional valve I 11 is connected to the inlet of the hydraulically controlled directional valve 12 and the middle and rear axle brake valves 14. The control end of the hydraulically controlled directional valve 12 is connected to the pressure oil source, and the output end of the hydraulically controlled directional valve 25 is connected to the control end of the brake pedal 2. The main brake valve of this invention is located at the center of the hydraulic system, connecting the front axle brake accumulator and the middle and rear axle brake accumulators, providing a pressure oil source for the brake pedal, the front axle proportional control valve group, the retarder valve, the middle and rear axle brake valves, the rear axle proportional valve group, and the relay valve group. The internal hydraulically controlled directional valve determines whether the brake pedal is operated by foot pedal action or automatically controlled by the main brake valve. The electromagnetic directional valve I determines whether to output pressure to the middle and rear axle brake valves.

[0032] like Figure 1 The diagram illustrates a wet disc brake hydraulic system for a mining dump truck. The brake pedal 2 has an inlet connected to a pressure oil source, and an outlet connected to a front axle proportional control valve group 3. A shuttle valve I 16 is located between the brake pedal 2 and the retarder valve 10, with its output connected to a rear axle proportional valve group 9. The brake pedal of this invention is a neutral-position closed control valve, automatically controlled by foot pedal operation or pressure applied by the main brake valve, applying pressure to both the front and rear brake circuits. The retarder valve can be operated via a lever, outputting insufficient braking pressure to the rear brake hydraulic circuit to reduce vehicle speed.

[0033] like Figure 1The diagram illustrates a wet disc brake hydraulic system for a mining dump truck. The front axle proportional control valve assembly 3 includes a proportional valve core I 31 and a shuttle valve II 32. The inlet of the proportional valve core I 31 is connected to a pressure oil source. The two ends of the shuttle valve II 32 are connected to the proportional valve core I 31 and the brake pedal 2, respectively. The outlet of the shuttle valve II 32 is connected to the inlet of the front axle brake valve assembly 4. This invention provides a wired operation system for the braking system. The proportional valve core I is controlled by wire, and the output pressure increases with increasing current. The front axle proportional control valve assembly incorporates the shuttle valve II. When braking pressure is present at either the proportional valve core I or the brake pedal, the shuttle valve II can be pushed to output pressure to the brake for braking.

[0034] like Figure 1 The diagram illustrates a wet disc brake hydraulic system for a mining dump truck. The front axle brake valve assembly 4 includes a solenoid directional valve II 41, a pressure reducing valve I 42, and a solenoid directional valve III 43. The outlet of the front axle brake valve assembly 4 is connected to the front brake cylinder 5. The inlet of the solenoid directional valve II 41 is connected to the inlet of the front axle brake valve assembly 4. The solenoid directional valve III 43 and the pressure reducing valve I 42 are connected in parallel to the outlet of the solenoid directional valve II 41. The outlet of the front axle main brake valve in this invention is connected to the front brake cylinder. The front axle main brake valve supplies pressurized hydraulic fluid to the front brake cylinder. When a 50% reduction in braking force is required, the solenoid directional valve III is energized, and the hydraulic fluid pressure is reduced through the pressure reducing valve I; conversely, the hydraulic system provides full braking pressure.

[0035] like Figure 1The diagram illustrates a wet disc brake hydraulic system for a mining dump truck. The middle and rear axle brake valve 6 includes an overflow valve 62 and a pressure reducing valve II 61. The input end of the middle and rear axle brake valve 6 is connected to the main control valve 1, and the output end of the middle and rear axle brake valve 6 is connected to a rear axle proportional valve group 9, a relay valve group 7, a rear axle brake cylinder 8, and a middle axle brake cylinder 15. The oil at the inlet end of the middle and rear axle brake valve 6 is divided into two paths after passing through the pressure reducing valve II 61. One path connects to the rear axle brake cylinder 8 and the middle axle brake cylinder 15, while the other path, after passing through damping, connects to shuttle valve IV 94 and shuttle valve V 72. The rear axle brake valve of this invention also includes a damper and a filter. The oil inlet of the rear axle brake valve is connected to the oil inlet of pressure reducing valve II. The oil outlet of pressure reducing valve II is connected to the filter and the parking piston chamber of the rear axle brake cylinder. The oil outlet of the filter is connected to the relief valve and the proportional valve group of the rear axle. In use, the hydraulic oil pressure decreases after passing through pressure reducing valve II. At this time, the pressure oil is divided into two paths. One path flows to the filter and damper. When the pressure after damping is less than the set pressure of the relief valve, the hydraulic oil flows to... In the rear axle proportional valve group, shuttle valve IV and shuttle valve V in the relay valve group are pressured to the upper part of shuttle valve IV and shuttle valve V, causing the valve core to move downward. The pressure is finally transmitted to the service piston chamber in the rear axle brake cylinder and the middle axle brake cylinder as back pressure, which improves the response speed when the service brake is applied. When the pressure is higher than the pressure set by the relief valve, the oil returns to the oil tank and is cleaned by the filter screen. Another line of pressurized oil is directly delivered to the parking piston chamber in the rear axle brake cylinder and the middle axle brake cylinder, which pushes open the spring device and finally releases the parking brake.

[0036] like Figure 1The hydraulic system for wet disc braking of a mining dump truck shown includes a rear axle proportional valve assembly 9 comprising a proportional valve core II 91, a shuttle valve III 92, a relay valve I 93, and a shuttle valve IV 94. The relay valve assembly 7 comprises a relay valve II 71 and a shuttle valve V 72. After the pressure oil source enters the rear axle proportional valve assembly 9, one path is used as power oil to supply relay valve I 93, and the other path is used as control oil to supply proportional valve core II 91. The output end of proportional valve core II 91 is connected to shuttle valve III 92. The other end is connected to shuttle valve I16. The output end of shuttle valve III92 is connected to the control end of relay valve I93 and relay valve II71. The oil outlet end of relay valve I93 is connected to the travel piston chamber of the rear axle brake cylinder 8 through shuttle valve IV94. The oil outlet end of relay valve II71 is connected to the travel piston chamber of the middle axle brake cylinder 15 through shuttle valve V72. The other end of shuttle valve IV94 and the other end of shuttle valve V72 are connected to the output end of the middle and rear axle brake valve 6. The relay valve group and the rear axle proportional valve group of this utility model have similar structures. The oil at the control end of both the relay valve group and the rear axle proportional valve group is supplied by the proportional valve core II in the rear axle proportional valve group. The rear axle proportional valve group has a similar function to the front axle proportional control valve group. The pressure oil of the proportional valve core II and the relay valve I is supplied by the rear brake accumulator. The proportional valve core II controls four relay valve cores at the same time, providing pressure to the middle axle brake cylinder and the rear axle brake cylinder respectively. A shuttle valve III is added between the proportional valve core II and the relay valve I to ensure that the control pressure output by the brake pedal or the retarder valve can also push the valve core of the relay valve I or the relay valve II to output braking pressure to the driving piston chamber of the middle and rear brakes. A shuttle valve is placed after the relay valve I and the relay valve II to ensure that the driving back pressure and the braking pressure output by the relay valve can reach the driving piston chamber in the middle and rear axle brake cylinders.

[0037] like Figure 1 The diagram illustrates a wet disc brake hydraulic system for a mining dump truck. The front brake cylinder is a caliper dry disc type. When braking is applied, pressurized oil acts on the piston end face inside the brake caliper, opposite to the brake pads. This pressurizes the brake pads and clamps the brake disc, thereby reducing wheel speed and achieving braking. The middle and rear axle brake cylinders are fully enclosed multi-disc brakes cooled by oil. Braking is achieved through spring force and hydraulic pressure. The service brake is applied by pressurizing the service piston chamber; while the parking brake requires depressurization of the parking piston chamber. The parking brake is applied by the spring force of an internal mechanical spring device pressing the friction pads and friction disc, and the parking brake is released by pressurizing the parking piston chamber to release the spring force.

[0038] like Figure 1 The hydraulic system for wet disc braking of a mining dump truck shown includes a solenoid directional valve II 41, which is a two-position two-way solenoid directional valve; a solenoid directional valve III 43, which is a two-position three-way solenoid directional valve; a solenoid directional valve I 11, which is a two-position four-way solenoid directional valve; and a hydraulically controlled directional valve 25, which is a two-position four-way hydraulically controlled directional valve.

[0039] like Figure 1 The hydraulic system for wet disc braking of a mining dump truck shown has filter elements at the oil inlet ends of the front axle proportional control valve group 3, the rear axle proportional valve group 9, and the relay valve group 7.

[0040] The operation of the wet disc brake hydraulic 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 conditions for emergency braking and parking braking are the same as in manual operation. Specific operations are as follows:

[0041] Manual driving

[0042] When braking is performed manually, the current value of the proportional valve cores I and II 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 pressure oil source will continuously replenish the pressure oil to the front axle brake accumulator and the middle and rear axle brake accumulators until the state stabilizes.

[0043] Normal driving conditions

[0044] During normal driving, the parking position needs to be released. Since the brake pedal is not required or the retarder lever is not pulled during normal driving, and there is no pressure in the upper pressure control chambers of relay valves I and II, the lower working output pressure of the relay valve core is 0. That is, the pressure on the left side of shuttle valve II, the lower side of shuttle valve IV, and the lower side of shuttle valve V is 0. At this time, solenoid directional valve I is energized, pushing the valve core to the left to the right position. The rear brake accumulator provides pressurized oil, which is then delivered by solenoid directional valve I to the middle and rear axle brake valves. The pressure is reduced by pressure reducing valve II, and the pressurized oil is then delivered to the driving piston chambers in the rear and middle axle brake cylinders as back pressure, and to the parking piston chambers in the rear and middle axle brake cylinders, ultimately releasing the parking position by pushing open the spring device. Solenoid directional valve II is not energized, therefore there is no braking pressure in the front axle master brake valve, the front axle proportional control valve group, and the front brake cylinder.

[0045] Manual driving - service brake

[0046] When electromagnetic directional valve I is energized, it operates in the right position. The hydraulic pressure in the parking piston chamber of the middle and rear axles pushes open the spring device to release the parking brake. When electromagnetic directional valve II is de-energized, it operates in the left position. The oil inlet of the front axle master brake valve is connected to the brake pedal through shuttle valve II. When the brake pedal is depressed, the pressure in the front axle brake accumulator and the middle and rear axle brake accumulators is transmitted to the front and rear brake circuits respectively, and the pressure oil source replenishes the accumulators. In the front brake circuit, the hydraulic fluid pushes the valve core of shuttle valve II to the left, entering the oil inlet port of the front axle master brake valve. When electromagnetic directional valve III is de-energized, it operates in the left position. The pressure oil enters the front brake cylinder directly through the one-way valve in electromagnetic directional valve III to provide full braking force. In the rear braking circuit, the solenoid directional valve I is energized and operates in the right position, releasing the parking brake. Since the retarder valve and the proportional valve core II do not output pressure, the pressure oil output from the brake pedal sequentially pushes the valve core of shuttle valve I to the right and the valve core of shuttle valve III to the left, establishing pressure in the control oil chambers on the upper side of relay valves I and II. The relay valve core moves down and outputs the service braking pressure to the lower part of shuttle valves IV and V. At this time, the service braking pressure at the lower part of shuttle valves IV and V is much higher than the service back pressure at the upper part of the shuttle valves. The valve cores of shuttle valves IV and V move up, and finally the service braking pressure will be input to the service piston chambers of the rear axle brake cylinder and the middle axle brake cylinder for braking.

[0047] Manual driving - parking brake;

[0048] After pressing the parking button, the solenoid directional valve I is de-energized and operates in the left position. The parking piston chambers of the middle and rear axle brake cylinders are directly connected to the hydraulic oil tank, thus cutting off the oil supply. There is no pressure in the oil within the parking piston chamber, so the spring device applies spring force to the parking brake for braking. The hydraulic directional valve, under the pressure of the right-side control chamber, moves to the left and operates in the right position. At this time, the pressure in the middle and rear brake accumulators enters the brake pedal through the solenoid directional valve I and the hydraulic directional valve, automatically applying braking force to the forward, middle, and rear hydraulic braking circuits. In the front brake hydraulic circuit, the solenoid directional valve II is energized, pushing the valve core to the left and operating in the right position, cutting off the oil supply. The front axle master brake valve is directly connected to the hydraulic oil tank; the shuttle valve II valve core moves to the left, and the oil pressure stops before the inlet of the solenoid directional valve II, while there is no pressure in the front brake cylinder. In the middle and rear braking circuits, the pressure oil output from the brake pedal also sequentially pushes the valve core of shuttle valve I to the right and the valve core of shuttle valve III to the left, establishing pressure in the control oil chambers on the upper side of relay valve I and relay valve II. The relay valve core operates in the upper position and inputs the pressure in the middle and rear axle brake accumulators into the driving piston chambers of the rear axle brake cylinder and the middle axle brake cylinder through the upward-moving valve cores of shuttle valves IV and V, applying pressure.

[0049] Manual driving - wet braking

[0050] When the vehicle encounters a slippery road surface, the braking force applied by the front brake cylinder is halved, while the middle and rear axle brake cylinders provide the full braking force. Electromagnetic directional valve II must not be energized to the left position, while electromagnetic directional valve I is energized to the right position. When the brake pedal is depressed, the rear brake circuit operates in the same manner as during service braking. The rear brake accumulator provides hydraulic pressure, which is output to the parking piston chamber via electromagnetic directional valve I and pressure reducing valve II, releasing the parking brake by pushing open the spring device. The brake pedal then outputs the pressure from the rear brake accumulator through shuttle valve I and shuttle valve III to the upper control oil chambers of relay valves I and II, building up pressure and pushing the valve cores of relay valves I and II downwards. Ultimately, the passage between the rear brake accumulator and the rear brake service piston chamber is opened, establishing braking pressure in the rear brake service piston chamber. In the front brake circuit, the solenoid directional valve III 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 I. Under the action of the pressure reducing valve, the pressure is halved and delivered to the front brake cylinder.

[0051] Manual driving - emergency braking;

[0052] 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 chamber of the hydraulic directional valve, causing the valve core to operate in the right-hand position, opening the passage between the main brake valve and the brake pedal. At this time, the pressure in the rear brake accumulator enters the brake pedal via solenoid directional valve I and the hydraulic directional valve, automatically applying braking force to the front and rear hydraulic braking circuits. In the front axle braking circuit, the shuttle valve II valve core moves to the left, solenoid directional valve II must not operate in the left-hand position. The pressurized oil supplied by the brake pedal flows through shuttle valve II, solenoid directional valve II, and solenoid directional valve III to apply full braking pressure to the front brake. In the rear axle braking circuit, the shuttle valve I valve core moves to the right, and the shuttle valve III valve core moves to the left. The pressurized oil output from the brake pedal also passes through shuttle valve I and shuttle valve III to the upper control oil chambers of relay valve I and relay valve II, where pressure is established. The control pressure pushes relay valves I and II downwards, causing the pressure output from the middle and rear axle brake accumulators in the main brake valve to force the valve cores of shuttle valves IV and V upwards. Pressurized oil is then input through shuttle valves IV and V to the traveling piston chambers of the middle and rear axle brake cylinders, applying pressure. Since the pressurized oil in the parking piston chambers of the middle and rear axle brake cylinders flows directly to the oil tank via the left position of solenoid valve I and has no pressure, the rear brakes automatically lock. At this point, all braking devices of the front and rear brakes are fully engaged, reducing the vehicle speed to zero and bringing it to a stop in the shortest possible time.

[0053] Manual driving - hydraulic easing braking

[0054] When traveling downhill, it is often necessary to apply partial braking force to the travel piston chambers of the middle and rear axle brake cylinders to reduce vehicle speed and achieve a slowing effect. This braking effect is achieved by pulling the slowing valve handle. During driving, solenoid directional valve I is energized and operates in the right position, while solenoid directional valve II 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 slowing valve handle outputs the oil in the middle and rear axle brake accumulators; the valve core of shuttle valve I moves to the left, and the valve core of shuttle valve III moves to the left. The pressurized oil is output through shuttle valves I and III to the upper control chambers of relay valves I and II and builds pressure, pushing relay valves I and II down; the pressurized oil in the rear brake accumulator passes through relay valves I and II, causing the valve cores of shuttle valves IV and V to move up, and finally input into the travel piston chambers of the middle and rear axle brake cylinders. At this time, there is no braking pressure in the front brake cylinder, and the pressure output by the retardation valve to the middle and rear brakes is relatively small, so the vehicle will brake and slow down to slowly pass through the downhill slope.

[0055] unmanned

[0056] 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 I30, 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 retarder valve 17 does not output braking pressure, and the brake pedal 19 does not output pressure when the solenoid directional valve I21 is energized in the right position. The following is a detailed explanation of the various braking states during driverless operation:

[0057] Unmanned driving - service brake

[0058] When electromagnetic directional valve I is energized, it operates in the right position. Oil from the middle and rear brake accumulators is transported through electromagnetic directional valve I and pressure reducing valve II to the parking piston chambers of the middle and rear axle brake cylinders, disengaging the mechanical spring device and releasing the parking brake. When electromagnetic directional valve II is de-energized, it operates in the left position, opening the oil inlet to the front axle main brake valve. There is no pressure on the right side of shuttle valves I and III. When brake-by-wire is required, relevant commands are issued from the ground control center. The controller and communication components, along with other electronic control system equipment, output current to the front and rear proportional valves I and II. The front, middle, and rear brake accumulators provide pressure oil sources to proportional valves I and II, 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 valves directly or using the pressure output from shuttle valve III (which moves to the right) establish control pressure in the upper pressure control chambers of relay valves I and II, respectively. Under the control pressure from the upper side, the relay valve core moves downward to the upper position, opening the passages between the front brake accumulator and the left side of shuttle valve I, and between the rear brake accumulator and the lower side of shuttle valve IV. This pushes the valve cores of shuttle valve I, shuttle valve IV, and shuttle valve V to the right and upward, respectively. In the front brake circuit, the solenoid directional valves II and I are not allowed to operate with their valve cores in the left position. The pressurized oil passes through shuttle valve II, solenoid directional valve III, and finally reaches the front brake cylinder to build up pressure for braking. In the rear brake circuit, the brake pressure output by relay valve I reaches the lower part of shuttle valve IV. The brake pressure is greater than the travel back pressure at the upper part of the shuttle valve, pushing the shuttle valve core upward, ultimately building up pressure in the travel piston chambers of the middle and rear brakes for braking.

[0059] Unmanned driving - wet braking

[0060] In autonomous driving mode, when braking is required on slippery roads, the braking force applied by the front brake cylinder is still halved, while the middle and rear axle brake cylinders provide sufficient braking force. During braking, the controller and communication components, along with other electronic control system equipment, output current to the front and rear proportional valve cores I and II. Electromagnetic directional valve II is not energized and operates in the left position, while electromagnetic directional valve I is energized and operates in 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 front axle proportional control valve group, as described in "Autonomous Driving - Service Braking" above. At this time, electromagnetic directional valve III is energized and operates in the right position. The pressure oil that originally passed through the valve core is blocked by the check valve, and the oil is redirected to pressure reducing valve I. Under the action of pressure reducing valve I, the pressure is halved and delivered to the front brake cylinder.

[0061] In autonomous driving, the hydraulic state of emergency braking mode and parking brake mode is the same as that of manual operation. Neither proportional valve core I nor proportional valve core II output pressure. The control is achieved through the energization logic of electromagnetic directional valve II and electromagnetic directional valve I, as described in the manual driving section above.

[0062] This utility model discloses a wet disc brake hydraulic system for a mining dump truck. The electronic control system controls the output pressure of the brake proportional valve group, which is then transmitted to the front, middle, and rear brake discs. A shuttle valve is used to connect manual braking via pedal valves with drive-by-wire braking. Under manual operation, pressurized oil from the brake valves is supplied to the pedal valves. Depressing the pedal valves transmits the pressurized oil to the front brake valves and the middle and rear axle brake valves, ultimately building pressure on the front, middle, and rear brake discs. The parking brake release pressure is directly provided by the brake valves. The main brake valves deliver oil to the middle and rear axle main brake valves, which adjust the pressure to the required level and transmit it to the rear brake disc release spring device, ultimately releasing the parking brake. For drive-by-wire unmanned mining truck braking systems, after receiving relevant commands from the ground control center, the controller and communication components control the output pressure of the brake proportional 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. This enables both manual braking and remote brake-by-wire functionality to be achieved simultaneously. Furthermore, the inclusion of a middle axle braking system and a rear axle braking system makes it more suitable for three-axle vehicles. This solves the problem of the long distance between the middle and rear axles and the main brake valve assembly in three-axle vehicles, improving braking response speed and enhancing driving safety.

[0063] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the present 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.

[0064] 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.

[0065] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. 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 utility model. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.

Claims

1. A wet disc brake hydraulic system for a mining dump truck, characterized in that: Includes a main control valve (1), one end of which is connected to a pressure oil source, and the other end of which is connected to the front braking system and the middle and rear braking system; The front braking system includes a brake pedal (2), a front axle proportional control valve group (3), a front axle brake valve group (4), and a front brake cylinder (5). The inlet end of the brake pedal (2) is connected to a pressure oil source, and one outlet end of the brake pedal (2) is connected to the front axle proportional control valve group (3). The front axle proportional control valve group (3) includes a proportional valve core I (31) and a shuttle valve II (32); the oil inlet end of the proportional valve core I (31) is connected to the pressure oil source, the two ends of the shuttle valve II (32) are respectively connected to the proportional valve core I (31) and the brake pedal (2), and the oil outlet end of the shuttle valve II (32) is connected to the oil inlet end of the front axle brake valve group (4); The front axle brake valve assembly (4) includes a solenoid directional valve II (41), a pressure reducing valve I (42) and a solenoid directional valve III (43), and the oil outlet of the front axle brake valve assembly (4) is connected to the front brake cylinder (5). The middle and rear braking system includes a brake pedal (2), a retarder valve (10), a middle and rear axle brake valve (6), a rear axle proportional valve group (9), a relay valve group (7), a rear axle brake cylinder (8), and a middle axle brake cylinder (15). A shuttle valve I (16) is provided between the brake pedal (2) and the retarder valve (10), and the output end of the shuttle valve I (16) is connected to the rear axle proportional valve group (9). The middle and rear axle brake valve (6) includes an overflow valve (62) and a pressure reducing valve II (61); the input end of the middle and rear axle brake valve (6) is connected to the main control valve (1), and the output end of the middle and rear axle brake valve (6) is connected to the rear axle proportional valve group (9), the relay valve group (7), the rear axle brake cylinder (8), and the middle axle brake cylinder (15). The rear axle proportional valve assembly (9) includes a proportional valve core II (91), a shuttle valve III (92), a relay valve I (93), and a shuttle valve IV (94). The relay valve assembly (7) includes a relay valve II (71) and a shuttle valve V (72). After the pressure oil source enters the rear axle proportional valve assembly (9), one path is delivered as power oil to the relay valve I (93), and the other path is delivered as control oil to the proportional valve core II (91). The output end of the proportional valve core II (91) is connected to the shuttle valve III (92), and the other end of the shuttle valve III (92) is connected to the shuttle valve. Ⅰ(16), the output end of shuttle valve Ⅲ(92) is connected to the control end of relay valve Ⅰ(93) and relay valve Ⅱ(71), the oil outlet end of relay valve Ⅰ(93) is connected to the travel piston chamber of the rear axle brake cylinder (8) through shuttle valve Ⅳ(94), the oil outlet end of relay valve Ⅱ(71) is connected to the travel piston chamber of the middle axle brake cylinder (15) through shuttle valve Ⅴ(72), and the other end of shuttle valve Ⅳ(94) and the other end of shuttle valve Ⅴ(72) are connected to the output end of the middle and rear axle brake valve (6); The main control valve (1) includes a solenoid directional valve I (11), a hydraulic directional valve (12), a front axle brake accumulator (13), and a middle and rear axle brake accumulator (14). The oil inlet of the solenoid directional valve I (11) is connected to a pressure oil source. The oil outlet of the solenoid directional valve I (11) is connected to the oil inlet of the hydraulic directional valve (12) and the middle and rear axle brake valve (6). The control end of the hydraulic directional valve (12) is connected to the pressure oil source. The output end of the hydraulic directional valve (25) is connected to the control end of the brake pedal (2).

2. The wet disc brake hydraulic system for a mining dump truck as described in claim 1, characterized in that: It also includes a front axle brake accumulator (13) and a middle and rear axle brake accumulator (14), the oil inlet ends of which are connected to a pressure oil source through a one-way valve.

3. The wet disc brake hydraulic system for a mining dump truck as described in claim 2, characterized in that: The oil outlet of the front axle brake accumulator (13) is connected to the front brake system; the oil outlet of the middle and rear axle brake accumulator (14) is divided into two paths, one path is connected to the rear brake system, and the other path is connected to the solenoid directional valve I (11).

4. The wet disc brake hydraulic system for a mining dump truck as described in claim 1, characterized in that: The oil inlet of the electromagnetic reversing valve II (41) is connected to the oil inlet of the front axle brake valve group (4), and the electromagnetic reversing valve III (43) and the pressure reducing valve I (42) are connected in parallel at the oil outlet of the electromagnetic reversing valve II (41).

5. The wet disc brake hydraulic system for a mining dump truck as described in claim 1, characterized in that: The oil inlet of the middle and rear axle brake valve (6) is divided into two paths after passing through pressure reducing valve II (61). One path connects to the rear axle brake cylinder (8) and the middle axle brake cylinder (15), while the other path connects to shuttle valve IV (94) and shuttle valve V (72) after passing through damping.

6. The wet disc brake hydraulic system for a mining dump truck as described in claim 1, characterized in that: The electromagnetic directional valve II (41) is a two-position two-way electromagnetic directional valve, the electromagnetic directional valve III (43) is a two-position three-way electromagnetic directional valve, the electromagnetic directional valve I (11) 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.

7. The wet disc brake hydraulic system for a mining dump truck as described in claim 1, characterized in that: The oil inlet ends of the front axle proportional control valve group (3), the rear axle proportional valve group (9), and the relay valve group (7) are all equipped with filter elements.

Images