Hydraulic braking system of unmanned mining dump truck and control method

Abstract

The invention discloses an unmanned mining dump truck hydraulic braking system and a control method. The unmanned mining dump truck hydraulic braking system comprises a service brake valve set and a parking brake valve set. The service brake valve group comprises a first hydraulic proportional pressure reducing valve, a second hydraulic proportional pressure reducing valve, a first shuttle valve and a first pressure sensor; the first hydraulic proportional pressure reducing valve and the second hydraulic proportional pressure reducing valve are connected in parallel; oil outlets of the first hydraulic proportional pressure reducing valve and the second hydraulic proportional pressure reducing valve are communicated with an oil inlet of a first shuttle valve; an oil outlet of the first shuttle valve is connected with a first pressure sensor; the parking brake valve group comprises an electromagnetic directional valve, a redundant electromagnetic directional valve and a pressure switch; the electromagnetic directional valve is a normally closed valve, and the redundant electromagnetic directional valve is a normally open valve; the electromagnetic directional valve and the redundant electromagnetic directional valve are connected in series, the electromagnetic directional valve is connected with an oil inlet pipeline, the redundant electromagnetic directional valve is connected with an oil outlet pipeline and a parking brake caliper, and a pressure switch is arranged on the oil outlet pipeline.

Description

Technical Field

[0001] The invention belongs to the field of unmanned mining dump trucks, and in particular relates to a hydraulic braking system and a control method for an unmanned mining dump truck. Background Art

[0002] Due to the limitation of axle structure, pneumatic brake mining dump trucks are currently limited to vehicles with a vehicle load of less than 100 tons. Mining dump trucks with a load of more than 100 tons require hydraulic brakes to meet the braking needs of the whole vehicle, and hydraulic brakes can meet the braking needs of mining dump trucks with a load of more than 30 tons. With the large demand for unmanned mining dump trucks, the demand for unmanned hydraulic brake systems has also emerged.

[0003] The unmanned hydraulic braking system is the core of the safe operation of unmanned mining dump trucks. It must not only meet the reliability, rapid response and precise control capabilities of unmanned vehicles to cope with complex working conditions and harsh environments, but also achieve digitalization and intelligence, and empower smart mines with "digital hydraulics".

[0004] At present, the braking system of unmanned mining dump trucks is mostly improved on the basis of the original hydraulic braking system of manually driven mining dump trucks, so as to meet the requirements of responding to the deceleration command and parking command issued by the unmanned driving control system under unmanned driving conditions; refer to the patent for details. In patent CN116901917A, a commercial vehicle wire-controlled redundant braking system and its control method are disclosed. The control system disclosed in the patent is based on the original braking control system, and a set of wire-controlled redundant braking units is added; that is, the vehicle braking control system of the patent is ultimately: the newly added electromagnetic proportional valve and the mechanical valve in the same braking circuit of the conventional brake valve constitute redundancy, and the redundant brake unit is connected to the conventional brake valve through a shuttle valve, which serves as a pilot air source to control the front and rear brakes respectively. The single-channel bridge control module of the front axle and the dual-channel bridge control module of the rear axle, the problems existing in this brake control system are: 1. The two air outlets of the redundant brake unit are connected to the air inlet of the shuttle valve, the two air outlets of the mechanical brake valve group are connected to the air inlet of the two shuttle valves, the front axle single-channel bridge control module and the rear axle dual-channel bridge control module are connected to the air outlets of the two shuttle valves, so the pipelines are complicated and inconvenient for maintenance; 2. The redundant valve group is redundant with the conventional valve group, and the system stability is poor: the sealing stability of the air-controlled shuttle valve is poor. When the redundant brake unit is working, it is very likely that the high-pressure gas will enter the conventional brake valve through the shuttle valve, which can easily cause the redundant brake unit to be connected to the air outlet of the conventional brake valve. At this time, the air outlet and the exhaust port of the conventional brake valve are connected, so the pilot pressure cannot be established, thereby the bridge control module cannot be controlled, and the redundancy fails.

[0005] Regarding the release of the parking brake of unmanned mining dump trucks, the existing technology requires changing the original hydraulic pilot handle control to an electronic parking switch, and the hydraulic pilot control parking valve to a hydraulic solenoid reversing valve, which can realize both manual parking and electronic parking functions. However, considering the safety of mining dump trucks, the entire vehicle is required to be in an effective parking state when unloading. In the unmanned driving system, the parking signal is associated with the lifting signal. When the unmanned driving control system does not receive a valid parking signal, it cannot issue a lifting command. If the parking solenoid valve is stuck or the electrical appliance fails, the unmanned mining dump truck cannot be lifted, which affects the effective operation of the vehicle. Summary of the invention

[0006] In order to solve the technical problems existing in the prior art, the present invention proposes a hydraulic braking system and a control method for an unmanned mining dump truck.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] In a first aspect, the present invention provides a hydraulic brake system for an unmanned mining dump truck, comprising a service brake valve group and a parking brake valve group;

[0009] The service brake valve group includes a first hydraulic proportional pressure reducing valve, a second hydraulic proportional pressure reducing valve, a first shuttle valve and a first pressure sensor; the first hydraulic proportional pressure reducing valve and the second hydraulic proportional pressure reducing valve are connected in parallel; the oil outlets of the first hydraulic proportional pressure reducing valve and the second hydraulic proportional pressure reducing valve are connected to the oil inlet of the first shuttle valve, and the oil outlet of the first shuttle valve is connected to the first pressure sensor;

[0010] The parking brake valve group includes an electromagnetic reversing valve, a redundant electromagnetic reversing valve, and a pressure switch; the electromagnetic reversing valve is a normally closed valve, and the redundant electromagnetic reversing valve is a normally open valve; the electromagnetic reversing valve and the redundant electromagnetic reversing valve are connected in series, the electromagnetic reversing valve is connected to the oil inlet pipeline, the redundant electromagnetic reversing valve is connected to the oil outlet pipeline connected to the parking brake caliper, and a pressure switch is installed on the oil outlet pipeline.

[0011] As a further technical solution, the service brake valve group is connected in parallel with the pedal valve and is connected via a second shuttle valve.

[0012] As a further technical solution, the oil inlets of the service brake valve group, the pedal valve and the parking brake valve group are connected to the same filling valve.

[0013] As a further technical solution, a service accumulator and a pressure sensor are arranged on the connecting pipeline between the liquid filling valve and the service brake valve group.

[0014] As a further technical solution, a parking accumulator is arranged on the connecting pipeline between the filling valve and the parking brake valve group.

[0015] As a further technical solution, a driving accumulator and a pressure sensor are arranged on the connecting pipeline between the filling valve and the pedal valve.

[0016] As a further technical solution, the parking brake valve group is further connected in series with a pressure reducing valve at the front end of the electromagnetic reversing valve.

[0017] As a further technical solution, the redundant electromagnetic reversing valve and the second hydraulic proportional pressure reducing valve are both connected to the alarm system of the mining dump truck. After the redundant electromagnetic reversing valve and the second hydraulic proportional pressure reducing valve are started, the alarm system of the mining dump truck is triggered.

[0018] As a further technical solution, the unmanned mining dump truck hydraulic brake system includes a hydraulic pump, and the hydraulic pump is connected to the filling valve after being connected to the filter.

[0019] In a second aspect, the present invention further provides a control method based on the above-mentioned unmanned mining dump truck hydraulic brake system, which is specifically as follows:

[0020] When the mining dump truck enters the braking mode under unmanned driving conditions, the control system sends a deceleration instruction, and the first pressure sensor collects the output pressure of the first hydraulic proportional pressure reducing valve in real time. If the difference between the collected pressure value and the set value exceeds the set range, it is determined that the first hydraulic proportional pressure reducing valve has failed, and the control system sends a braking signal to the second hydraulic proportional pressure reducing valve. At this time, the second hydraulic proportional pressure reducing valve outputs braking pressure to ensure the reliability of braking performance; if the difference between the collected pressure value and the set value is within the set range, it is determined that the first hydraulic proportional pressure reducing valve is effective, and the second hydraulic proportional pressure reducing valve is not started;

[0021] When a mining dump truck enters the parking release mode under unmanned driving conditions, the control system issues a parking release command, the solenoid reversing valve is energized to open, and parking is achieved; if the solenoid reversing valve fails during parking, the pressure switch receives a high-voltage signal and sends a signal to the overall control system. The vehicle control system controls the redundant solenoid reversing valve to open and relieve pressure.

[0022] The beneficial effects of the present invention are as follows:

[0023] The mining dump truck proposed by the present invention directly adds a set of redundant braking system on the pedal-type manual braking system; the braking system is provided with a first hydraulic proportional pressure reducing valve and a second hydraulic proportional pressure reducing valve, and the first hydraulic proportional pressure reducing valve and the second hydraulic proportional pressure reducing valve can be redundant with each other, that is, two proportional pressure reducing valves with equal functions (main brake + redundant brake) are connected by a hydraulic shuttle valve to ensure the reliability of unmanned driving braking performance; at the same time, in the parking release system of the present invention, by adding a redundant electromagnetic reversing valve, it is ensured that when the parking electromagnetic valve is stuck in a power-free state, the pressure switch obtains a high-voltage signal and sends a signal to the overall control system, and the vehicle control system controls the redundant electromagnetic reversing valve to open and release the pressure, so that the dump truck is always in a parking state, does not affect the normal lifting function of the dump truck, and can ensure the reliability of the parking function. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of the hydraulic brake system of the unmanned mining dump truck proposed by the present invention;

[0025] Figure 2 is a schematic diagram of a service brake valve group in a hydraulic brake system provided by the present invention;

[0026] Figure 3 is a schematic diagram of a parking brake valve group in a hydraulic brake system provided by the present invention;

[0027] In the figure: 1 hydraulic pump, 2 filter, 3 charging valve, 4 service brake valve group, 5 service accumulator, 6 second pressure sensor, 7 pedal valve, 8 second shuttle valve, 9 service brake caliper, 10 relay valve, 11 parking brake caliper, 12 parking brake valve group, 13 parking accumulator;

[0028] 41 a first hydraulic proportional pressure reducing valve, 42 a second hydraulic proportional pressure reducing valve, 43 a first shuttle valve, 44 a first pressure sensor;

[0029] 121 electromagnetic reversing valve, 122 pressure reducing valve, 123 redundant electromagnetic reversing valve, 124 pressure switch, 125 third pressure sensor; DETAILED DESCRIPTION

[0030] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0031] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless otherwise explicitly stated in the present invention, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "include" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof;

[0032] In order to solve the technical problems existing in the prior art, the present invention proposes a hydraulic brake system and a control method for an unmanned mining dump truck. Specifically, the hydraulic brake system for an unmanned mining dump truck mainly consists of a hydraulic pump 1, a filter 2, a filling valve 3, a service brake valve group 4, a service accumulator 5, a second pressure sensor 6, a pedal valve 7, a second shuttle valve 8, a service brake caliper 9, a relay valve 10, a parking brake caliper 11, a parking brake valve group 12, and a parking accumulator 13; the hydraulic pump 1 is connected to the filter 2 through a pipeline, the filter 2 is connected to the filling valve 3, and the filling valve 3 is respectively connected to the service brake valve group 4, the pedal valve 7, the second shuttle valve 8, the service brake caliper 9, the relay valve 10, the parking brake caliper 11, the parking brake valve group 12, and the parking accumulator 13. The plate valve 7 is connected to the parking brake valve group 12, wherein the pedal valve 7 and the service brake valve group 4 are connected in parallel through the second shuttle valve 8; the second shuttle valve 8 is connected to the relay valve 10, and the relay valve 10 is connected to the parking brake caliper 9 on the vehicle; the parking brake valve group 12 is connected to the parking brake caliper 11; a service accumulator 5 and a second pressure sensor 6 are arranged on the connecting oil line between the charging valve 3 and the service brake valve group 4; a parking accumulator 13 is also arranged on the connecting pipeline between the charging valve 3 and the parking brake valve group 12; a service accumulator 5 and a second pressure sensor 6 are arranged on the connecting pipeline between the charging valve 3 and the pedal valve 7,

[0033] The functions and specific structures of each component are explained below:

[0034] Among them, the hydraulic pump 1 provides a power source for the hydraulic brake system. When the vehicle is powered by the engine, the hydraulic pump 1 is driven by the engine; when the vehicle is powered by new energy, it is driven by an electric motor to form an oil pump motor group, which is used in conjunction with the filling valve 3. The vehicle controller controls the start and stop of the oil pump motor group according to the system pressure, thereby realizing the automatic start and stop function of the oil pump motor group and achieving energy-saving effects.

[0035] Filter 2 is a high-pressure filter with a built-in blockage pressure alarm switch. When the impurities in the filter exceed the standard and the pressure alarm switch alarms, the entire vehicle triggers a fault prompt and the high-pressure filter element needs to be replaced.

[0036] The filling valve 3 is a dual-way filling valve, which can provide two oil sources with the same pressure and flow for the hydraulic service brake system, and also provide a parking oil source for the hydraulic parking brake system;

[0037] The two service accumulators 5 are respectively connected to the two outlets of the dual-way filling valve 3 , and the service accumulators 5 provide an emergency oil source for the service brake system and eliminate the pressure shock of the brake system.

[0038] The two second pressure sensors 6 respectively feed back the pressure of the two hydraulic brake circuits to the vehicle controller.

[0039] The pedal valve 7, the service brake valve group 4 and the shuttle valve 8 constitute the switching control logic between manned and unmanned driving, so that the manned braking circuit and the unmanned braking circuit form a parallel structure; specifically, the pedal valve 7 has two circuits, the oil outlet of one circuit and the oil outlet of the service brake valve group 4 are connected to the two oil inlets of a shuttle valve; the oil outlet of the other circuit and the oil outlet of the service brake valve group 4 are connected to the two oil inlets of another shuttle valve; so that the pedal valve 7 and the service brake valve group 4 form a parallel system;

[0040] The external control ports of the two relay valves 10 are respectively connected to the outlets of the two second shuttle valves 8 , and the opening of the relay valve 10 is controlled by the second shuttle valve 8 , thereby controlling the on-off of the pressure oil between the relay valve 10 and the service brake caliper 9 .

[0041] The parking accumulator 13 is connected to the long-through oil port for filling liquid, so as to provide an emergency oil source for the parking brake system and eliminate the pressure shock of the parking brake system.

[0042] Furthermore, when the mining dump truck is in unmanned operation, it follows the "safety first" principle, and the hydraulic proportional pressure reducing valve is a "sliding valve" structure; if the hydraulic brake system is not maintained in time, it will cause debris in the hydraulic oil, and the debris in the hydraulic oil will cause the proportional pressure reducing valve to occasionally get stuck. The stuck proportional pressure reducing valve will cause the service brake to fail, and the safety of the vehicle cannot be guaranteed; therefore, in the embodiment, while the first hydraulic proportional pressure reducing valve 41 meets the vehicle performance requirements, a group of redundant second hydraulic proportional pressure reducing valves 42 should be added to improve the safety and reliability of unmanned mining dump trucks. Specifically, the service brake valve group 4 includes two groups of first hydraulic proportional pressure reducing valves 41 and second hydraulic proportional pressure reducing valves 42 with the same functions; it also includes a first shuttle valve 43 and a first pressure sensor 44, which together constitute the control logic of the main brake and redundant brake; in this embodiment, the first hydraulic proportional pressure reducing valve 1-1 is used as the main brake valve, and the second hydraulic proportional pressure reducing valve 1-2 is used as the redundant brake valve for explanation, see for details. Figure 2 ;

[0043] The oil inlet P and the oil return T of the first hydraulic proportional pressure reducing valve 41 and the second hydraulic proportional pressure reducing valve 42 are connected through the internal oil passage of the valve block, respectively, so as to realize the "parallel" connection of the first hydraulic proportional pressure reducing valve 41 and the second hydraulic proportional pressure reducing valve 42; the oil outlet A of the first hydraulic proportional pressure reducing valve 41 and the second hydraulic proportional pressure reducing valve 42 are connected to the two oil inlet holes of the first shuttle valve 43 through the internal oil passage of the valve block, respectively, and the first pressure sensor 44 is connected to the oil outlet pipeline of the first shuttle valve 43; when the mining dump truck is driving under unmanned driving conditions, the output pressure of the proportional valve corresponding to the deceleration instruction issued by the unmanned driving system is compared with the pressure fed back by the first pressure sensor 44. If the difference exceeds the set range, it is determined that the main brake valve (the first hydraulic proportional pressure reducing valve 41) fails, and at the same time, a braking signal is sent to the redundant brake valve (the second hydraulic proportional pressure reducing valve 42), and the redundant brake valve (the second hydraulic proportional pressure reducing valve 42) outputs the braking pressure to ensure the reliability of the braking performance; the pressure sensor 44 collects the pressure at the outlet of the shuttle valve to the vehicle controller.

[0044] In the present invention, two hydraulic proportional pressure reducing valves with the same functions are redundant with each other, that is, when one hydraulic proportional pressure reducing valve is used as the main brake valve, the other hydraulic proportional pressure reducing valve is used as a redundant brake valve. The service brake valve group 4 integrates the main brake and redundant brake functions, and there is no need to connect to the main brake valve group in the existing dump truck; during the entire unmanned braking process, the first hydraulic proportional pressure reducing valve 41 is used to provide redundant brake pressure output for the front axle and the middle and rear axles at the same time; the second hydraulic proportional pressure reducing valve 42 does not work under normal circumstances. When the first hydraulic proportional pressure reducing valve 41 fails to drive the vehicle due to jamming or other faults, the second hydraulic proportional pressure reducing valve 42 is immediately started to provide redundant brake pressure output for the front axle and the middle and rear axles.

[0045] The first hydraulic proportional pressure reducing valve 41 and the second hydraulic proportional pressure reducing valve 42 can output different pressures according to the magnitude of the current signal, and the linear output of the hydraulic braking force of the axle can be achieved through the hydraulic proportional pressure reducing valves.

[0046] Further, such as Figure 3 As shown, the parking brake valve group 12 in this embodiment includes an electromagnetic reversing valve 121, a pressure reducing valve 122, a redundant electromagnetic reversing valve 123, a pressure switch 124 and a pressure sensor 125, and the electromagnetic reversing valve 121, the pressure reducing valve 122, the redundant electromagnetic reversing valve 123, the pressure switch 124 and the pressure sensor 125 constitute the control logic of the main parking brake and the redundant parking brake; wherein the pressure switch 124 provides a parking signal to feed back the real-time parking condition to the whole vehicle; the pressure sensor 125 detects the pressure in the real-time parking oil circuit; specifically,

[0047] After the parking oil source enters the valve block, it first passes through the pressure reducing valve 2 to ensure that the pressure entering the parking solenoid valve is constant.

[0048] The P port of the electromagnetic reversing valve 121 is connected to the charging valve 3 via a pipeline, and the oil pressure is provided by the charging valve 3; the A port of the electromagnetic reversing valve 121 is connected to the P port of the redundant electromagnetic reversing valve 123; the T ports of the electromagnetic reversing valve 121 and the redundant electromagnetic reversing valve 123 are both connected back to the oil tank; the A port of the redundant electromagnetic reversing valve 123 is connected to the parking brake caliper pipeline, wherein the T port is connected back to the oil tank alone and is not allowed to be combined with other return oil pipelines to ensure the reliability of the valve operation.

[0049] The parking brake caliper has the function of "oil-off brake". When the electromagnetic reversing valve 121 is not powered, its P port is blocked and the A port is connected to the T port, which is equivalent to a normally closed valve. When the redundant electromagnetic reversing valve 123 is not powered, the P port is connected to the A port ( Figure 2 ), that is, it is a normally open valve, so when the vehicle is without power, there is no pressure in the parking brake caliper and it is in the "parking state";

[0050] When the vehicle needs to release the parking condition, the electromagnetic reversing valve 121 is energized, and then the electromagnetic reversing valve 121 is opened, and the pressure oil enters the redundant electromagnetic reversing valve 123 through the P port of the electromagnetic reversing valve 121 to the parking brake caliper, and the parking brake caliper obtains the set pressure, so that the whole vehicle is in the "release parking state"; in this process, the redundant electromagnetic reversing valve 123 is not energized and is in a smooth state;

[0051] When the vehicle needs to be in the parking state, the electromagnetic reversing valve 121 needs to be powered off. At this time, if it is stuck or the electrical signal is lost, and the pressure switch 124 has not received a low-pressure signal, the vehicle control system controls the redundant electromagnetic reversing valve 123 to open and release the pressure, so that the dump truck is always in the parking state without affecting the normal lifting function of the dump truck; and once the redundant electromagnetic reversing valve 123 is started, the parking brake fault alarm of the whole vehicle is triggered. The background staff can make an assessment based on the actual situation and decide whether the faulty vehicle continues to operate or returns to the station for repair.

[0052] The pressure sensor 125 detects the pressure in the oil circuit in real time. If the pressure in the oil circuit is greater or less than the set pressure value, it means that the solenoid reversing valve 121 does not open normally after being energized or the redundant solenoid reversing valve fails; the vehicle parking brake failure alarm is triggered, and the back-end staff can make an assessment based on the actual situation and decide whether the faulty vehicle should continue to operate or return to the station for repair.

[0053] In order to ensure the safety of the whole vehicle, in the unmanned driving mode, the pedal valve will automatically switch to the manual driving mode after being stepped on, realizing the "manual priority" function. In the manual driving mode, the service brake is controlled by the brake pedal, which is consistent with traditional vehicles; the parking brake is an electronic switch, replacing the traditional parking handle. In the unmanned driving mode, when the vehicle is started in situ, it automatically enters the parking mode; after sending the throttle signal, the vehicle controller sends a signal to release the parking brake. In the unmanned driving mode, the vehicle inclination sensor can detect whether it is parked on a slope. If it is on a slope, the braking force is automatically maintained to prevent the vehicle from sliding. Realize the slope assist function In the unmanned driving mode, when the control system detects an emergency, the system automatically sends the maximum braking force command to all brake modules to ensure the shortest distance parking. Realize the emergency braking function.

[0054] During unmanned driving, the vehicle's unmanned driving domain controller sends a deceleration command to the vehicle controller based on actual needs. The vehicle controller sends a current signal to the proportional pressure reducing valve in the service brake valve group based on the deceleration value. The proportional pressure reducing valve opens to a certain degree to transmit braking pressure to the service brake caliper, and the vehicle starts braking.

[0055] At the same time, the pressure sensor in the service brake valve group feeds back the brake pressure to the vehicle controller. The vehicle controller compares the difference between the preset pressure and the fed-back brake pressure. If the difference exceeds the set range, it is determined that the main brake valve has failed. At the same time, a brake signal is sent to the redundant brake valve, and the redundant brake valve outputs the brake pressure to ensure the reliability of the braking performance. After the redundant brake valve is started, the vehicle's service brake fault alarm is triggered. The background staff can make an assessment based on the actual situation and decide whether the faulty vehicle should continue to operate or return to the station for repair.

[0056] In this embodiment, the highly integrated service brake valve group and parking brake valve group are an integrated valve group, which can reduce the usage of pipelines and effectively reduce the possibility of leakage of hydraulic pipelines.

[0057] In this embodiment, in the new energy unmanned mining vehicle, the automatic start and stop function of the motor pump has a significant effect on reducing the energy consumption of the entire vehicle.

[0058] The high-pressure filter in this embodiment has a clogging alarm function, which can realize intelligent detection of the cleanliness of the hydraulic oil in the hydraulic brake system, so that the filter element is replaced instead of regularly, and the replacement cycle of the hydraulic oil is effectively extended, thereby reducing the maintenance cost of the whole vehicle.

[0059] The unmanned mining vehicle in this embodiment also has a ramp assist function: in the unmanned driving mode, the vehicle inclination sensor can detect whether it is parked on a ramp. If it is on a ramp, the braking force is automatically maintained to prevent the vehicle from sliding.

[0060] The unmanned mining car in this embodiment also has an emergency braking function: in the unmanned driving mode, when the control system detects an emergency situation, the system automatically issues a maximum braking force command to ensure the shortest distance parking.

[0061] The unmanned mining car in this embodiment also has the function of adding an accumulator to each brake branch to reduce the impact of the hydraulic system: when the hydraulic brake system is turned on and off, the sudden rise and fall of the system pressure may cause the pipelines and components to be subjected to a certain pressure impact, and the accumulator can absorb the impact.

[0062] The unmanned mining car in this embodiment also has an accumulator added to each brake branch to supplement the oil source: improve the response speed of the braking system

[0063] The unmanned mining vehicle in this embodiment also has an accumulator added to each brake branch as an emergency power source: to provide emergency braking force when the main pump fails.

Claims

1. A hydraulic brake system for an unmanned mining dump truck, comprising a service brake valve group and a parking brake valve group; characterized in that: The service brake valve group includes a first hydraulic proportional pressure reducing valve, a second hydraulic proportional pressure reducing valve, a first shuttle valve and a first pressure sensor; the first hydraulic proportional pressure reducing valve and the second hydraulic proportional pressure reducing valve are connected in parallel; the oil outlets of the first hydraulic proportional pressure reducing valve and the second hydraulic proportional pressure reducing valve are connected to the oil inlet of the first shuttle valve, and the oil outlet of the first shuttle valve is connected to the first pressure sensor; The parking brake valve group includes an electromagnetic reversing valve, a redundant electromagnetic reversing valve, and a pressure switch; the electromagnetic reversing valve is a normally closed valve, and the redundant electromagnetic reversing valve is a normally open valve; the electromagnetic reversing valve and the redundant electromagnetic reversing valve are connected in series, the electromagnetic reversing valve is connected to the oil inlet pipeline, the redundant electromagnetic reversing valve is connected to the oil outlet pipeline connected to the parking brake caliper, and a pressure switch is installed on the oil outlet pipeline.

2. The unmanned mining dump truck hydraulic brake system according to claim 1, characterized in that: The service brake valve group is connected in parallel with the pedal valve and is connected via a second shuttle valve.

3. The unmanned mining dump truck hydraulic brake system according to claim 1, characterized in that: The oil inlets of the service brake valve group, the pedal valve and the parking brake valve group are connected to the same filling valve.

4. The unmanned mining dump truck hydraulic brake system according to claim 3, characterized in that: A service accumulator and a pressure sensor are arranged on the connecting pipeline between the liquid filling valve and the service brake valve group.

5. The hydraulic brake system for an unmanned mining dump truck according to claim 3, characterized in that: A parking accumulator is arranged on the connecting pipeline between the filling valve and the parking brake valve group.

6. The unmanned mining dump truck hydraulic brake system according to claim 3, characterized in that: A driving accumulator and a pressure sensor are arranged on the connecting pipeline between the liquid filling valve and the pedal valve.

7. The unmanned mining dump truck hydraulic brake system according to claim 1, characterized in that: The parking brake valve group is also connected in series with a pressure reducing valve at the front end of the electromagnetic reversing valve.

8. The unmanned mining dump truck hydraulic brake system according to claim 1, characterized in that: The redundant electromagnetic reversing valve and the second hydraulic proportional pressure reducing valve are both connected to the alarm system of the mining dump truck. After the redundant electromagnetic reversing valve and the second hydraulic proportional pressure reducing valve are started, the alarm system of the mining dump truck is triggered.

9. The unmanned mining dump truck hydraulic brake system according to claim 1, characterized in that: The hydraulic brake system of the unmanned mining dump truck comprises a hydraulic pump, which is connected to the filling valve after being connected to the filter.

10. The control method of the hydraulic brake system of the unmanned mining dump truck according to any one of claims 1 to 9, characterized in that: When the mining dump truck enters the braking mode under unmanned driving conditions, the control system sends a deceleration instruction, and the first pressure sensor collects the output pressure of the first hydraulic proportional pressure reducing valve in real time. If the difference between the collected pressure value and the set value exceeds the set range, it is determined that the first hydraulic proportional pressure reducing valve has failed, and the control system sends a braking signal to the second hydraulic proportional pressure reducing valve. At this time, the second hydraulic proportional pressure reducing valve outputs braking pressure to ensure the reliability of braking performance; if the difference between the collected pressure value and the set value is within the set range, it is determined that the first hydraulic proportional pressure reducing valve is effective, and the second hydraulic proportional pressure reducing valve is not started; When a mining dump truck enters the parking release mode under unmanned driving conditions, the control system issues a parking release command, the solenoid reversing valve is energized to open, and parking is achieved; if the solenoid reversing valve fails during parking, the pressure switch receives a high-voltage signal and sends a signal to the overall control system. The vehicle control system controls the redundant solenoid reversing valve to open and relieve pressure.

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