Self-unloading mine truck without driver, double-redundancy hydraulic four-wheel steering system and method

Abstract

The application discloses a kind of double redundancy hydraulic four-wheel steering systems, comprising: steering valve group, plunger pump, hydraulic oil tank, front axle steering cylinder, first electro-hydraulic steering valve, second electro-hydraulic steering valve, rear axle steering cylinder, third electro-hydraulic steering valve, fourth electro-hydraulic steering valve, first flow amplifier, second flow amplifier, first confluence valve group, second confluence valve group.The application also discloses a kind of unmanned mine dump truck and double redundancy hydraulic four-wheel steering method.The application realizes the steering action of front and rear steering cylinders by four electro-hydraulic steering valves control two flow amplifiers, meets the steering requirement of bidirectional travel, while, realizes front and rear axle double redundancy steering function, improves steering safety.

Description

Technical Field

[0001] This invention belongs to the field of unmanned electric wheel mining dump trucks, specifically relating to an unmanned mining dump truck, a dual-redundant hydraulic four-wheel steering system and method. Background Technology

[0002] Electric wheel mining dump trucks are off-highway dump trucks, mainly used for transporting minerals in large open-pit mines. They consist of a frame, power system, running gear, electrical system, and hydraulic system. The hydraulic steering system is a crucial component of the electric wheel mining dump truck, playing a vital role in the vehicle's handling and safety.

[0003] With the development of autonomous driving technology and the construction of intelligent mining areas in recent years, the technology of autonomous mining dump trucks has become increasingly mature. Some domestic and foreign mining truck manufacturers have successively released autonomous mining truck products, which can realize four-wheel steering and two-way driving, greatly improving transportation efficiency. The traditional one-way driving hydraulic steering system of mining trucks no longer meets the requirements of new mining trucks, and the safety of autonomous driving also needs to be greatly improved. Summary of the Invention

[0004] The purpose of this invention is to provide an unmanned mining dump truck, a dual-redundant hydraulic four-wheel steering system and method, which uses four electro-hydraulic steering valves to control two flow amplifiers to realize the steering action of the front and rear steering cylinders, meet the steering requirements of bidirectional driving, and realize the dual-redundant steering function of the front and rear axles, thereby improving steering safety.

[0005] To achieve the above objectives, the technical solution used in this invention is:

[0006] The dual-redundant hydraulic four-wheel steering system includes: a steering valve assembly, a piston pump, a hydraulic oil tank, a front axle steering cylinder, a first electro-hydraulic steering valve, a second electro-hydraulic steering valve, a first flow amplifier, and a first merging valve assembly.

[0007] A plunger pump is used to pressurize hydraulic oil. Its inlet is connected to the hydraulic oil tank through a pipeline, and its outlet is connected to the inlet P1 of the steering valve assembly through a pipeline.

[0008] The steering valve assembly is used to supply pressurized oil to the first flow amplifier. The return port T is connected to the oil tank through a pipeline. The outlet port STR1 of the steering valve assembly is connected to the inlet port HP of the first flow amplifier through a pipeline.

[0009] The first electro-hydraulic steering valve and the second electro-hydraulic steering valve receive control signals and output pilot pressure oil to the first flow amplifier. The oil inlet, oil return, and oil outlet of the first electro-hydraulic steering valve and the second electro-hydraulic steering valve are respectively connected to the oil inlet, oil return, and oil outlet of the first flow amplifier through the first confluence valve group.

[0010] The first flow amplifier is used to control the steering mechanism of the front axle. Its oil outlet is connected to the front axle steering cylinder through a pipeline. The front axle steering cylinder is used to control the steering of the front wheels.

[0011] Furthermore, it also includes: a second flow amplifier, a rear axle steering cylinder, a third electro-hydraulic steering valve, a fourth electro-hydraulic steering valve, and a second confluence valve assembly; the steering valve assembly is used to supply pressurized oil to the first and second flow amplifiers, and its outlet STR2 port is connected to the inlet HP port of the second flow amplifier through a pipeline; the third electro-hydraulic steering gear and the fourth electro-hydraulic steering valve respectively receive control signals and output pilot pressurized oil to the second flow amplifier, and their inlet, return, and outlet ports are connected to the inlet, return, and outlet ports of the second flow amplifier through the second confluence valve assembly; the second flow amplifier is used to control the steering mechanism of the rear axle, and its outlet port is connected to the rear axle steering cylinder through a pipeline, and the rear axle steering cylinder is used to control the steering of the rear wheels.

[0012] Furthermore, the front axle steering cylinder includes: a front axle left steering cylinder and a front axle right steering cylinder. The oil outlet CL and oil outlet CR of the first flow amplifier are respectively connected to the front axle left steering cylinder and the front axle right steering cylinder through pipelines. The oil outlet CL and oil outlet CR of the second flow amplifier are respectively connected to the rear axle left steering cylinder and the rear axle right steering cylinder through pipelines. The return ports of the first flow amplifier, the second flow amplifier, and the steering valve assembly are connected to the hydraulic oil tank through pipelines.

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

[0014] Furthermore, the hydraulic oil is converted into high-pressure oil by the plunger pump and enters the P1 port of the steering valve assembly through pipelines. The STR1 and STR2 ports of the steering valve assembly are connected to the HP port of the first flow amplifier and the HP port of the second flow amplifier through pipelines, respectively. The L, R, P, T, and LS ports of the first and second electro-hydraulic steering valves are connected to the L, R, P, T, and LS ports of the first flow amplifier through the first confluence valve assembly, respectively. The L, R, P, T, and LS ports of the third and fourth electro-hydraulic steering valves are connected to the L, R, P, T, and LS ports of the second flow amplifier through the second confluence valve assembly, respectively. The CL and CR ports of the first flow amplifier are connected to the left and right steering cylinders of the front axle through pipelines, respectively, to control the steering of the front wheels. The CL and CR ports of the second flow amplifier are connected to the left and right steering cylinders of the rear axle, respectively, to control the steering of the rear wheels, and return to the hydraulic oil tank through the HT port of the first and second flow amplifiers and the T port of the steering valve assembly.

[0015] Furthermore, the steering valve assembly is an integrated valve, including: a solenoid directional valve, a throttle valve, a safety valve, and a check valve. Accumulators are installed at ports A1, A2, and A3. The safety valve is installed between ports P1, P2, and T. The solenoid directional valve is located between ports P1 and T. The throttle valve is located between the solenoid directional valve and port P. The check valve is located after port P1 and before ports A1 and A2.

[0016] Furthermore, a pressure sensor is installed at the TSB port of the steering valve assembly, and the pressure sensor is connected to a pressure switch via a wire.

[0017] The unmanned mining dump truck includes a dual-redundant hydraulic four-wheel steering system.

[0018] A dual-redundant hydraulic four-wheel steering method for unmanned mining dump trucks includes:

[0019] The plunger pump outputs pressurized oil to the steering valve assembly, which in turn provides pressurized oil to the first flow amplifier and the second flow amplifier.

[0020] The first and second electro-hydraulic steering valves receive control signals and output pilot pressure oil to the first flow amplifier; the third and fourth electro-hydraulic steering valves receive control signals and output pilot pressure oil to the second flow amplifier. The first flow amplifier controls the steering mechanism of the front axle, and the second flow amplifier controls the steering mechanism of the rear axle.

[0021] Preferably, when the vehicle is moving forward, the first electro-hydraulic steering valve and the second electro-hydraulic steering valve control the first flow amplifier to perform a steering action on the front steering cylinder, making the front wheels of the vehicle the active steering wheels; when the vehicle is moving backward, the third electro-hydraulic steering valve and the fourth electro-hydraulic steering valve control the second flow amplifier to perform a steering action on the rear steering cylinder, making the rear wheels of the vehicle the active steering wheels.

[0022] Preferably, the first and second electro-hydraulic steering valves output pilot pressure oil to the first flow amplifier under the control of an electrical signal. The outlet CL and outlet CR of the first flow amplifier are connected to the front axle steering cylinder to control the steering mechanism of the front axle. Excess pressure oil returns to the hydraulic oil tank through the HT port of the first flow amplifier and the return oil filter. The third and fourth electro-hydraulic steering valves output pilot pressure oil to control the second flow amplifier under the control of an electrical signal. The outlet CL and outlet CR of the second flow amplifier are connected to the rear axle steering cylinder to control the steering mechanism of the rear axle. Excess pressure oil returns to the hydraulic oil tank through the return oil filter of the HT port of the second flow amplifier.

[0023] The technical effects of this invention include:

[0024] 1. This invention adopts the principle of controlling one flow amplifier with every two electro-hydraulic directional valves to achieve dual redundancy directional function of a single flow amplifier.

[0025] Two electro-hydraulic steering valves are used to provide pilot control oil to the flow amplifier. The two flow amplifiers control the steering cylinders of the front and rear axles respectively. The front and rear axles use redundant steering control with electro-hydraulic steering valves. Even if one of the electro-hydraulic steering valves fails, the steering function of the mine car will not be affected.

[0026] 2. This invention is easy to implement and improves the safety of the hydraulic steering function of unmanned mining trucks. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structural principle of the dual-redundant hydraulic four-wheel steering system for the unmanned mining dump truck in this invention.

[0028] The components include: 1. Steering valve assembly; 1.1. Shut-off valve; 1.2. Throttle valve; 1.3. Safety valve; 1.4. Check valve; 2. Piston pump; 3. Hydraulic oil tank; 4. Filter; 5. Accumulator; 6. Pressure switch; 7. Front axle left steering cylinder; 8. Front axle right steering cylinder; 9. First electro-hydraulic steering valve; 10. Second electro-hydraulic steering valve; 11. Rear axle left steering cylinder; 12. Rear axle right steering cylinder; 13. Third electro-hydraulic steering valve; 14. Fourth electro-hydraulic steering valve; 15. First flow amplifier; 16. Second flow amplifier; 17. First merging valve assembly; 18. Second merging valve assembly. Detailed Implementation

[0029] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.

[0030] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0031] In this disclosure, the terms "upper," "lower," "inner," "middle," "outer," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for better description of the embodiments of this disclosure and their implementations, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to require them to be constructed and operated in a specific orientation. Furthermore, some of the aforementioned terms may be used to indicate other meanings besides orientation or positional relationship; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in the embodiments of this disclosure according to the specific circumstances.

[0032] Furthermore, the terms "set up," "connect," and "fix" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0033] Unless otherwise stated, the term "multiple" means two or more.

[0034] In this embodiment of the disclosure, the character " / " indicates that the objects before and after it are in an "or" relationship. For example, A / B means: A or B.

[0035] The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0036] It should be noted that, unless otherwise specified, the embodiments and features described in this disclosure can be combined with each other. The following description fully illustrates specific embodiments of the invention to enable those skilled in the art to practice and reproduce them.

[0037] like Figure 1 The diagram shown is a schematic diagram of the dual-redundant hydraulic four-wheel steering system of this invention.

[0038] The dual-redundant hydraulic four-wheel steering system is applied to unmanned mining dump trucks; the hydraulic oil tank 3 is a storage device for hydraulic oil; the plunger pump 2 provides pressure and flow to the system; among the four electro-hydraulic steering valves, each pair of electro-hydraulic steering valves provides pilot control oil to a flow amplifier; the steering cylinder acts as an actuator to drive the vehicle steering mechanism to complete steering.

[0039] The dual-redundant hydraulic four-wheel steering system includes: steering valve assembly 1, piston pump 2, hydraulic oil tank 3, front axle left steering cylinder 7, front axle right steering cylinder 8, first electro-hydraulic steering valve (EHI) 9, second electro-hydraulic steering valve (EHI) 10, rear axle left steering cylinder 11, rear axle right steering cylinder 12, third electro-hydraulic steering valve (EHI) 13, fourth electro-hydraulic steering valve 14, first flow amplifier 15, second flow amplifier 16, first merging valve assembly 17, and second merging valve assembly 18.

[0040] Hydraulic oil is converted into high-pressure oil by plunger pump 2 and enters the P1 port (inlet) of steering valve assembly 1 through pipeline. The STR1 port (outlet) and STR2 port (outlet) of steering valve assembly 1 are respectively connected to the HP port (inlet) of the first flow amplifier 15 and the HP port (inlet) of the second flow amplifier 16 through pipeline. The L, R, P, T, and LS ports of the first electro-hydraulic steering valve 9 and the second electro-hydraulic steering valve 10 are respectively connected to the L, R, P, T, and LS ports of the first flow amplifier 15 through the first confluence valve assembly 17. The L and R ports of the third electro-hydraulic steering gear 13 are connected to the L and R ports of the fourth electro-hydraulic steering valve 14. The P, T, and LS ports are connected to the L, R, P, T, and LS ports of the second flow amplifier 16 respectively via the second confluence valve group 18; the CL and CR ports of the first flow amplifier 15 are connected to the front axle steering cylinders (front left steering cylinder 7 and front right steering cylinder 8) via pipelines to control the steering of the front wheels; the CL (outlet) and CR (outlet) ports of the second flow amplifier 16 are connected to the rear axle steering cylinders (rear left steering cylinder 11 and rear right steering cylinder 12) to control the steering of the rear wheels, and return to the hydraulic oil tank 3 through the HT port of the first flow amplifier 15, the second flow amplifier 16, and the T port of the steering valve group 1.

[0041] The plunger pump 2 is used to pressurize the hydraulic oil. Its inlet is connected to the hydraulic oil tank 3 through a pipeline, and its outlet is connected to the P1 port (inlet) of the steering valve assembly 1 through a pipeline. The plunger pump 2 is a constant pressure variable pump.

[0042] Steering valve assembly 1 is used to supply pressurized oil to the first flow amplifier 15 and the second flow amplifier 16. The T port (return port) is connected to the oil tank 3 through a pipeline. The STR1 port (outlet port) of steering valve assembly 1 is connected to the HP port of the first flow amplifier 15 through a pipeline. The STR2 port (outlet port) of steering valve assembly 1 is connected to the HP port (inlet port) of the second flow amplifier 16 through a pipeline.

[0043] The first electro-hydraulic steering valve 9 receives control signals and outputs pilot pressure oil. The first flow amplifier 15 has its P port (inlet) and T port (return port) connected to the P port and T port of the first flow amplifier 15 respectively through pipelines. The L port (inlet) of the first electro-hydraulic steering valve 9 is connected to the L1 port (inlet) of the first confluence valve group 17 through a pipeline, the R port (return port) is connected to the R1 port (return port) of the first confluence valve group 17 through a pipeline, and the LS1 port (outlet) is connected to the LS2 port (outlet) of the first confluence valve group 17 through a pipeline.

[0044] The second electro-hydraulic steering valve 10 receives control signals and outputs pilot pressure oil to the second flow amplifier 16. Its P port (inlet) and T port (return port) are connected to the P port and T port of the first flow amplifier 15 through pipelines, respectively. The L port (inlet) of the second electro-hydraulic steering valve 10 is connected to the L2 port (inlet) of the first confluence valve group 17, and the R port (return port) of the second electro-hydraulic steering valve 10 is connected to the R2 port (return port) of the first confluence valve group 17. The LS1 port (outlet) of the second electro-hydraulic steering valve 10 is connected to the LS3 port (outlet) of the first confluence valve group 17 through a pipeline.

[0045] The first flow amplifier 15 is used to control the steering mechanism of the front axle. Its L port (oil inlet) is connected to the L3 port (oil inlet) of the first confluence valve group 17 via a pipeline; its R port is connected to the R3 port (oil return port) of the first confluence valve group 17 via a pipeline; and its LS port (oil outlet) is connected to the LS1 port (oil outlet) of the first confluence valve group 17 via a pipeline. The CL of the first flow amplifier 15 is connected to the C1 port of the left steering cylinder 7 of the front axle and to the C2 port of the right steering cylinder 8 of the front axle. The CR of the first flow amplifier 15 is connected to the C2 port of the left steering cylinder 7 of the front axle and to the C2 port of the right steering cylinder 8 of the front axle. The HT port (oil return port) of the first flow amplifier 15 is connected to the oil tank 3 via a pipeline.

[0046] The P port (oil inlet) and T port (oil return port) of the third electro-hydraulic steering valve 13 are connected to the P port and T port of the second flow amplifier 16 respectively through pipelines. The L port (oil inlet) of the third electro-hydraulic steering valve 13 is connected to the L1 port (oil inlet) of the second confluence valve group 18 through pipelines. The R port (oil return port) of the third electro-hydraulic steering valve 13 is connected to the R1 port (oil return port) of the second confluence valve group 18 through pipelines. The LS1 port (oil outlet) of the third electro-hydraulic steering valve 13 is connected to the LS2 port (oil outlet) of the second confluence valve group 18.

[0047] The P port (oil inlet) and T port (oil return port) of the fourth electro-hydraulic steering valve 14 are connected to the P port and T port of the second flow amplifier 16 respectively through pipelines. The L port is connected to the L2 port (oil inlet) of the second confluence valve group 18 through a pipeline, and the R port (oil return port) is connected to the R2 port (oil return port) of the second confluence valve group 18 through a pipeline. The LS1 port (oil outlet) of the fourth electro-hydraulic steering valve 14 is connected to the LS3 port (oil outlet) of the second confluence valve group 18.

[0048] The second flow amplifier 16 controls the steering mechanism of the rear axle. The L port (oil inlet) is connected to the L3 port (oil inlet) of the second confluence valve group 18 through a pipeline. The R port (oil return port) is connected to the R3 port (oil return port) of the second confluence valve group 18 through a pipeline. The LS port (oil outlet) is connected to the LS1 port (oil outlet) of the second confluence valve group 18.

[0049] The CL of the second flow amplifier 16 is connected to the C1 port of the left steering cylinder 11 of the rear axle and the C2 port of the right steering cylinder 12 of the rear axle. The CR of the second flow amplifier 16 is connected to the C2 port of the left steering cylinder 11 of the rear axle and the C1 port of the right steering cylinder 12 of the rear axle. The HT port (return port) of the second flow amplifier 16 is connected to the oil tank 3 through pipelines.

[0050] The specific steps of the dual-redundant hydraulic four-wheel steering method for unmanned mining dump trucks are as follows:

[0051] Step 1: The plunger pump 2 outputs pressurized oil to the steering valve assembly 1;

[0052] Step 2: The steering valve assembly 1 supplies pressurized oil to the first flow amplifier 15 and the second flow amplifier 16 respectively.

[0053] The STR1 and STR2 ports of the steering valve assembly 1 are respectively connected to the HP ports of the first flow amplifier 15 and the second flow amplifier 16. The P, T, L, R, and LS ports of the first flow amplifier 15 are respectively connected to the P, T, L, R, and LS ports of the first electro-hydraulic steering valve 9 and the second electro-hydraulic steering valve 10 through the first confluence valve assembly 17. The steering valve assembly 1 provides pressurized oil to the first flow amplifier 15 and the second flow amplifier 16.

[0054] Step 3: The first electro-hydraulic steering valve 9 and the second electro-hydraulic steering valve 10 receive control signals and output pilot pressure oil to the first flow amplifier 15; the third electro-hydraulic steering valve 13 and the fourth electro-hydraulic steering valve 14 receive control signals and output pilot pressure oil to the second flow amplifier 16. The first flow amplifier 15 controls the steering mechanism of the front axle to move, and the second flow amplifier 16 controls the steering mechanism of the rear axle to move.

[0055] Under the control of electrical signals, the first electro-hydraulic steering valve 9 and the second electro-hydraulic steering valve 10 output pilot pressure oil to the first flow amplifier 15. The CL port (oil outlet) and CR port (oil outlet) of the first flow amplifier 15 are connected to the front axle steering cylinder to control the steering mechanism of the front axle. Excess pressure oil returns to the hydraulic oil tank 3 through the HT port of the first flow amplifier 15 and the return oil filter.

[0056] The P, T, L, R, and LS ports of the second flow amplifier 16 are respectively connected to the P, T, L, R, and LS ports of the third electro-hydraulic steering valve 13 and the fourth electro-hydraulic steering valve 14 via the second confluence valve group 18. Under the control of an electrical signal, the third electro-hydraulic steering valve 13 and the fourth electro-hydraulic steering valve 14 output pilot pressure oil to control the second flow amplifier 16. The CL port (outlet) and CR port (outlet) of the second flow amplifier 16 are connected to the rear axle steering cylinder to control the steering mechanism of the rear axle. Excess pressure oil returns to the hydraulic oil tank 3 through the return oil filter at the HT port of the second flow amplifier 16.

[0057] When the vehicle is moving forward, the first electro-hydraulic steering valve 9 and the second electro-hydraulic steering valve 10 control the first flow amplifier 15 to perform a steering action on the front steering cylinder, making the front wheels of the vehicle the active steering wheels; when the vehicle is moving backward, the third electro-hydraulic steering valve 13 and the fourth electro-hydraulic steering valve 14 control the second flow amplifier 16 to perform a steering action on the rear steering cylinder, making the rear wheels of the vehicle the active steering wheels.

[0058] Each individual flow amplifier (first flow amplifier 15 / second flow amplifier 16) is controlled in parallel by two electro-hydraulic steering valves (first electro-hydraulic steering valve 9, second electro-hydraulic steering valve 10, or third electro-hydraulic steering valve 13, fourth electro-hydraulic steering valve 14). Even if a single electro-hydraulic steering valve fails, the other electro-hydraulic steering valve can still provide a control signal to ensure that the vehicle steering does not lose control, thus realizing the dual redundant hydraulic steering function of the front and rear axles.

[0059] Example 1: The vehicle moves forward

[0060] The dual-redundant hydraulic four-wheel steering system includes: steering valve assembly 1, piston pump 2, hydraulic oil tank 3, front axle left steering cylinder 7, front axle right steering cylinder 8, first electro-hydraulic steering valve (EHI) 9, second electro-hydraulic steering valve (EHI) 10, first flow amplifier 15, and first merging valve assembly 17.

[0061] Hydraulic oil is converted into high-pressure oil by plunger pump 2 and enters the P1 port (inlet) of steering valve assembly 1 through pipeline. The STR1 port (outlet) and STR2 port (outlet) of steering valve assembly 1 are respectively connected to the HP port (inlet) of the first flow amplifier 15 through pipeline. The L port, R port, P port, T port, and LS port of the first electro-hydraulic steering valve 9 and the second electro-hydraulic steering valve 10 are respectively connected to the L port, R port, P port, T port, and LS port of the first flow amplifier 15 through the first confluence valve assembly 17. The CL port and CR port of the first flow amplifier 15 are respectively connected to the front axle steering cylinder (front axle left steering cylinder 7 and front axle right steering cylinder 8) through pipeline to control the steering of the front wheels. The oil returns to the hydraulic oil tank 3 through the T port of the steering valve assembly 1 of the first flow amplifier 15.

[0062] The plunger pump 2 is used to pressurize the hydraulic oil. Its inlet is connected to the hydraulic oil tank 3 through a pipeline, and its outlet is connected to the P1 port (inlet) of the steering valve assembly 1 through a pipeline. The plunger pump 2 is a constant pressure variable pump.

[0063] Steering valve assembly 1 is used to supply pressurized oil to the first flow amplifier 15. The T port (return port) is connected to the oil tank 3 through a pipeline. The STR1 port (outlet port) of steering valve assembly 1 is connected to the HP port of the first flow amplifier 15 through a pipeline.

[0064] The first electro-hydraulic steering valve 9 receives control signals and outputs pilot pressure oil. The first flow amplifier 15 has its P port (inlet) and T port (return port) connected to the P port and T port of the first flow amplifier 15 respectively through pipelines. The L port (inlet) of the first electro-hydraulic steering valve 9 is connected to the L1 port (inlet) of the first confluence valve group 17 through a pipeline, the R port (return port) is connected to the R1 port (return port) of the first confluence valve group 17 through a pipeline, and the LS1 port (outlet) is connected to the LS2 port (outlet) of the first confluence valve group 17 through a pipeline.

[0065] The second electro-hydraulic steering valve 10 receives control signals and outputs pilot pressure oil to the second flow amplifier 16. Its P port (inlet) and T port (return port) are connected to the P port and T port of the first flow amplifier 15 through pipelines, respectively. The L port (inlet) of the second electro-hydraulic steering valve 10 is connected to the L2 port (inlet) of the first confluence valve group 17, and the R port (return port) of the second electro-hydraulic steering valve 10 is connected to the R2 port (return port) of the first confluence valve group 17. The LS1 port (outlet) of the second electro-hydraulic steering valve 10 is connected to the LS3 port (outlet) of the first confluence valve group 17 through a pipeline.

[0066] The first flow amplifier 15 is used to control the steering mechanism of the front axle. Its L port (oil inlet) is connected to the L3 port (oil inlet) of the first confluence valve group 17 through a pipeline, its R port is connected to the R3 port (oil return port) of the first confluence valve group 17 through a pipeline, and its LS port (oil outlet) is connected to the LS1 port (oil outlet) of the first confluence valve group 17 through a pipeline. The CL of the first flow amplifier 15 is connected to the C1 port of the left steering cylinder 7 of the front axle and the C2 port of the right steering cylinder 8 of the front axle. The CR of the first flow amplifier 15 is connected to the C2 port of the left steering cylinder 7 of the front axle and the C2 port of the right steering cylinder 8 of the front axle. The HT port (oil return port) of the first flow amplifier 15 is connected to the oil tank 3 through a pipeline.

[0067] The specific steps of the dual-redundant hydraulic four-wheel steering method for unmanned mining dump trucks are as follows:

[0068] Step 1: The plunger pump 2 outputs pressurized oil to the steering valve assembly 1;

[0069] Step 2: The steering valve assembly 1 supplies pressurized oil to the first flow amplifier 15.

[0070] The STR1 and STR2 ports of the steering valve assembly 1 are connected to the HP port of the first flow amplifier 15. The P, T, L, R, and LS ports of the first flow amplifier 15 are respectively connected to the P, T, L, R, and LS ports of the first electro-hydraulic steering valve 9 and the second electro-hydraulic steering valve 10 through the first confluence valve assembly 17. The steering valve assembly 1 provides pressurized oil to the first flow amplifier 15.

[0071] Step 3: The first electro-hydraulic steering valve 9 and the second electro-hydraulic steering valve 10 receive control signals and output pilot pressure oil to the first flow amplifier 15; the first flow amplifier 15 controls the steering mechanism of the front axle to operate.

[0072] Under the control of electrical signals, the first electro-hydraulic steering valve 9 and the second electro-hydraulic steering valve 10 output pilot pressure oil to the first flow amplifier 15. The CL port (oil outlet) and CR port (oil outlet) of the first flow amplifier 15 are connected to the front axle steering cylinder to control the steering mechanism of the front axle. Excess pressure oil returns to the hydraulic oil tank 3 through the HT port of the first flow amplifier 15 and the return oil filter.

[0073] When the vehicle moves forward, the first electro-hydraulic steering valve 9 and the second electro-hydraulic steering valve 10 control the first flow amplifier 15 to perform steering action on the front steering cylinder, making the front wheels of the vehicle the active steering wheels. Each individual flow amplifier (the first flow amplifier 15) is controlled in parallel by two electro-hydraulic steering valves (the first electro-hydraulic steering valve 9 and the second electro-hydraulic steering valve 10). Even if a single electro-hydraulic steering valve fails, the other electro-hydraulic steering valve can still provide a control signal to ensure that the vehicle steering does not lose control, thus realizing the dual redundant hydraulic steering function of the front and rear axles.

[0074] Example 2: Vehicle moving backward

[0075] The dual-redundant hydraulic four-wheel steering system includes: steering valve assembly 1, piston pump 2, hydraulic oil tank 3, rear axle left steering cylinder 11, rear axle right steering cylinder 12, third electro-hydraulic steering valve (EHI) 13, fourth electro-hydraulic steering valve 14, second flow amplifier 16, and second merging valve assembly 18.

[0076] Hydraulic oil is converted into high-pressure oil by plunger pump 2 and enters the P1 port (inlet) of steering valve assembly 1 through pipeline. The STR2 port (outlet) of steering valve assembly 1 is connected to the HP port (inlet) of the second flow amplifier 16 through pipeline. The L port, R port, P port, T port, and LS port of the third electro-hydraulic steering gear 13 and the fourth electro-hydraulic steering valve 14 are respectively connected to the L port, R port, P port, T port, and LS port of the second flow amplifier 16 through the second confluence valve assembly 18. The CL port (outlet) and CR port (outlet) of the second flow amplifier 16 are connected to the rear axle steering cylinders (rear axle left steering cylinder 11 and rear axle right steering cylinder 12) to control the steering of the rear wheels and return to the hydraulic oil tank 3 through the HT port of the second flow amplifier 16 and the T port of steering valve assembly 1.

[0077] The plunger pump 2 is used to pressurize the hydraulic oil. Its inlet is connected to the hydraulic oil tank 3 through a pipeline, and its outlet is connected to the P1 port (inlet) of the steering valve assembly 1 through a pipeline. The plunger pump 2 is a constant pressure variable pump.

[0078] Steering valve assembly 1 is used to supply pressurized oil to the second flow amplifier 16. The T port (return port) is connected to the oil tank 3 through a pipeline. The STR2 port (outlet port) of steering valve assembly 1 is connected to the HP port (inlet port) of the second flow amplifier 16 through a pipeline.

[0079] The P port (oil inlet) and T port (oil return port) of the third electro-hydraulic steering valve 13 are connected to the P port and T port of the second flow amplifier 16 respectively through pipelines. The L port (oil inlet) of the third electro-hydraulic steering valve 13 is connected to the L1 port (oil inlet) of the second confluence valve group 18 through pipelines. The R port (oil return port) of the third electro-hydraulic steering valve 13 is connected to the R1 port (oil return port) of the second confluence valve group 18 through pipelines. The LS1 port (oil outlet) of the third electro-hydraulic steering valve 13 is connected to the LS2 port (oil outlet) of the second confluence valve group 18.

[0080] The P port (oil inlet) and T port (oil return port) of the fourth electro-hydraulic steering valve 14 are connected to the P port and T port of the second flow amplifier 16 respectively through pipelines. The L port is connected to the L2 port (oil inlet) of the second confluence valve group 18 through a pipeline, and the R port (oil return port) is connected to the R2 port (oil return port) of the second confluence valve group 18 through a pipeline. The LS1 port (oil outlet) of the fourth electro-hydraulic steering valve 14 is connected to the LS3 port (oil outlet) of the second confluence valve group 18.

[0081] The second flow amplifier 16 controls the steering mechanism of the rear axle. The L port (oil inlet) is connected to the L3 port (oil inlet) of the second confluence valve group 18 through a pipeline. The R port (oil return port) is connected to the R3 port (oil return port) of the second confluence valve group 18 through a pipeline. The LS port (oil outlet) is connected to the LS1 port (oil outlet) of the second confluence valve group 18.

[0082] The CL of the second flow amplifier 16 is connected to the C1 port of the left steering cylinder 11 of the rear axle and the C2 port of the right steering cylinder 12 of the rear axle. The CR of the second flow amplifier 16 is connected to the C2 port of the left steering cylinder 11 of the rear axle and the C1 port of the right steering cylinder 12 of the rear axle. The HT port (return port) of the second flow amplifier 16 is connected to the oil tank 3 through pipelines.

[0083] The specific steps of the dual-redundant hydraulic four-wheel steering method for unmanned mining dump trucks are as follows:

[0084] Step 1: The plunger pump 2 outputs pressurized oil to the steering valve assembly 1;

[0085] Step 2: The steering valve assembly 1 supplies pressurized oil to the first flow amplifier 15 and the second flow amplifier 16 respectively.

[0086] The STR2 port of the steering valve assembly 1 is connected to the HP port of the second flow amplifier 16, and the steering valve assembly 1 provides pressurized oil to the second flow amplifier 16.

[0087] Step 3: The third electro-hydraulic steering valve 13 and the fourth electro-hydraulic steering valve 14 receive control signals and output pilot pressure oil to the second flow amplifier 16. The second flow amplifier 16 controls the steering mechanism of the rear axle to operate.

[0088] The P, T, L, R, and LS ports of the second flow amplifier 16 are respectively connected to the P, T, L, R, and LS ports of the third electro-hydraulic steering valve 13 and the fourth electro-hydraulic steering valve 14 via the second confluence valve group 18. Under the control of an electrical signal, the third electro-hydraulic steering valve 13 and the fourth electro-hydraulic steering valve 14 output pilot pressure oil to control the second flow amplifier 16. The CL port (outlet) and CR port (outlet) of the second flow amplifier 16 are connected to the rear axle steering cylinder to control the steering mechanism of the rear axle. Excess pressure oil returns to the hydraulic oil tank 3 through the return oil filter at the HT port of the second flow amplifier 16.

[0089] When the vehicle is moving backward, the third electro-hydraulic steering valve 13 and the fourth electro-hydraulic steering valve 14 control the second flow amplifier 16 to perform steering action on the rear steering cylinder, so that the rear wheels of the vehicle act as the active steering wheels.

[0090] Each individual flow amplifier (second flow amplifier 16) is controlled in parallel by two electro-hydraulic steering valves (third electro-hydraulic steering valve 13 and fourth electro-hydraulic steering valve 14). Even if a single electro-hydraulic steering valve fails, the other electro-hydraulic steering valve can still provide a control signal to ensure that the vehicle steering does not lose control, thus realizing the dual redundant hydraulic steering function of the front and rear axles.

[0091] Example 3: Based on Example 1 or 2, a suction filter and a high-pressure filter 4 are installed before and after the plunger pump 2. The HT port (return port) of the first flow amplifier 15 and the second flow amplifier 16 are connected to a return filter through a pipeline, and the hydraulic oil returns to the oil tank 3 through the return filter. Inside the steering valve assembly 1, between the P1 port and the T port, there are a solenoid directional valve 1.1, a throttle valve 1.2, a safety valve 1.3, and a check valve 1.4, which are connected in series between the P1 port and the T port.

[0092] The specific steps of the dual-redundant hydraulic four-wheel steering method for unmanned mining dump trucks are as follows:

[0093] Step 1: The plunger pump 2 outputs pressurized oil to the steering valve assembly 1;

[0094] The oil outlet of the plunger pump 2 is connected to the P1 port of the steering valve assembly 1 through the high-pressure filter 4. The hydraulic oil is converted into high-pressure oil by the plunger pump 2, and the high-pressure oil enters the steering valve assembly 1 through the suction filter.

[0095] Step 2: The steering valve assembly 1 supplies pressurized oil to the first flow amplifier 15 and the second flow amplifier 16 respectively.

[0096] After the pressurized oil enters the steering valve assembly 1, it first passes through a check valve 1.4 and a safety valve 1.3 to protect the system components from damage caused by excessive pressure. The solenoid directional valve 1.1 and the throttle valve 1.2 ensure that the accumulator pressure is released within a certain period of time after the vehicle stops.

[0097] The STR1 and STR2 ports of the steering valve assembly 1 are respectively connected to the HP ports of the first flow amplifier 15 and the second flow amplifier 16. The P, T, L, R, and LS ports of the first flow amplifier 15 are respectively connected to the P, T, L, R, and LS ports of the first electro-hydraulic steering valve 9 and the second electro-hydraulic steering valve 10 through the first confluence valve assembly 17. The steering valve assembly 1 provides pressurized oil to the first flow amplifier 15 and the second flow amplifier 16.

[0098] Step 3: The first electro-hydraulic steering valve 9 and the second electro-hydraulic steering valve 10 receive control signals and output pilot pressure oil to the first flow amplifier 15; the third electro-hydraulic steering valve 13 and the fourth electro-hydraulic steering valve 14 receive control signals and output pilot pressure oil to the second flow amplifier 16. The first flow amplifier 15 controls the steering mechanism of the front axle to move, and the second flow amplifier 16 controls the steering mechanism of the rear axle to move.

[0099] Under the control of electrical signals, the first electro-hydraulic steering valve 9 and the second electro-hydraulic steering valve 10 output pilot pressure oil to the first flow amplifier 15. The CL port (oil outlet) and CR port (oil outlet) of the first flow amplifier 15 are connected to the front axle steering cylinder to control the steering mechanism of the front axle. Excess pressure oil returns to the hydraulic oil tank 3 through the HT port of the first flow amplifier 15 and the return oil filter.

[0100] The P, T, L, R, and LS ports of the second flow amplifier 16 are respectively connected to the P, T, L, R, and LS ports of the third electro-hydraulic steering valve 13 and the fourth electro-hydraulic steering valve 14 via the second confluence valve group 18. Under the control of an electrical signal, the third electro-hydraulic steering valve 13 and the fourth electro-hydraulic steering valve 14 output pilot pressure oil to control the second flow amplifier 16. The CL port (outlet) and CR port (outlet) of the second flow amplifier 16 are connected to the rear axle steering cylinder to control the steering mechanism of the rear axle. Excess pressure oil returns to the hydraulic oil tank 3 through the return oil filter at the HT port of the second flow amplifier 16.

[0101] When the vehicle moves forward, the first electro-hydraulic steering valve 9 and the second electro-hydraulic steering valve 10 control the first flow amplifier 15 to perform steering action on the front steering cylinder, so that the front wheels of the vehicle act as the active steering wheels.

[0102] Example 4: Based on Examples 1 and 2, accumulators 5 are installed at ports A1, A2, and A3 (working oil ports) of steering valve assembly 1. Accumulators 5 provide pressure and flow to provide emergency steering function for the system, meet the emergency steering requirements of the vehicle, and reduce system pressure pulses.

[0103] Example 5: Pressure sensors are installed at the TSB ports (working oil ports) of steering valve assemblies 1 and 2. The pressure sensors are connected to pressure switch 6 via wires. When the steering pressure is low, pressure switch 6 activates the alarm device.

[0104] The foregoing description and accompanying drawings fully illustrate embodiments of the present disclosure to enable those skilled in the art to practice them. Other embodiments may include structural and other changes. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the order of operation may vary. Parts and features of some embodiments may be included or substituted for parts and features of other embodiments. Embodiments of the present disclosure are not limited to the structures described above and shown in the accompanying drawings, and various modifications and changes may be made without departing from its scope. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A dual-redundant hydraulic four-wheel steering system, characterized in that, include: Steering valve assembly, piston pump, hydraulic oil tank, front axle steering cylinder, first electro-hydraulic steering valve, second electro-hydraulic steering valve, first flow amplifier, first merging valve assembly; second flow amplifier, rear axle steering cylinder, third electro-hydraulic steering valve, fourth electro-hydraulic steering valve, second merging valve assembly; A plunger pump is used to pressurize hydraulic oil. Its inlet is connected to the hydraulic oil tank through a pipeline, and its outlet is connected to the inlet P1 of the steering valve assembly through a pipeline. The steering valve assembly is used to supply pressurized oil to the first flow amplifier and the second flow amplifier. The return port T is connected to the oil tank through a pipeline. The outlet port STR1 of the steering valve assembly is connected to the inlet port HP of the first flow amplifier through a pipeline, and the outlet port STR2 is connected to the inlet port HP of the second flow amplifier through a pipeline. The first electro-hydraulic steering valve and the second electro-hydraulic steering valve receive control signals and output pilot pressure oil to the first flow amplifier. The oil inlet, oil return, and oil outlet of the first electro-hydraulic steering valve and the second electro-hydraulic steering valve are respectively connected to the oil inlet, oil return, and oil outlet of the first flow amplifier through the first confluence valve group. The third electro-hydraulic steering gear and the fourth electro-hydraulic steering valve receive control signals and output pilot pressure oil to the second flow amplifier, respectively. Their oil inlet, oil return, and oil outlet are connected to the oil inlet, oil return, and oil outlet of the second flow amplifier through the second confluence valve group. The first flow amplifier is used to control the steering mechanism of the front axle. Its oil outlet is connected to the front axle steering cylinder through a pipeline. The front axle steering cylinder is used to control the steering of the front wheels. The front axle steering cylinder includes: the front axle left steering cylinder and the front axle right steering cylinder. The oil outlets CL and CR of the first flow amplifier are connected to the front axle left steering cylinder and the front axle right steering cylinder through pipelines, respectively. The second flow amplifier is used to control the steering mechanism of the rear axle. Its oil outlet is connected to the rear axle steering cylinder through a pipeline. The rear axle steering cylinder is used to control the steering of the rear wheels. The rear axle steering cylinder includes a left rear axle steering cylinder and a right rear axle steering cylinder. The oil outlets CL and CR of the second flow amplifier are connected to the left rear axle steering cylinder and the right rear axle steering cylinder through pipelines, respectively. The return ports of the first flow amplifier, the second flow amplifier, and the steering valve assembly are connected to the hydraulic oil tank through pipelines.

2. The dual-redundant hydraulic four-wheel steering system as described in claim 1, characterized in that, Hydraulic oil is converted into high-pressure oil by a plunger pump and enters the P1 port of the steering valve assembly through pipelines. The STR1 and STR2 ports of the steering valve assembly are connected to the HP port of the first flow amplifier and the HP port of the second flow amplifier through pipelines, respectively. The L, R, P, T, and LS ports of the first and second electro-hydraulic steering valves are connected to the L, R, P, T, and LS ports of the first flow amplifier through the first confluence valve assembly, respectively. The L, R, P, T, and LS ports of the third and fourth electro-hydraulic steering valves are connected to the L, R, P, T, and LS ports of the second flow amplifier through the second confluence valve assembly, respectively. The CL and CR ports of the first flow amplifier are connected to the left and right steering cylinders of the front axle through pipelines, respectively, to control the steering of the front wheels. The CL and CR ports of the second flow amplifier are connected to the left and right steering cylinders of the rear axle, respectively, to control the steering of the rear wheels. The oil returns to the hydraulic oil tank through the HT port of the first and second flow amplifiers and the T port of the steering valve assembly.

3. The dual-redundant hydraulic four-wheel steering system as described in claim 1, characterized in that, The steering valve assembly is an integrated valve, including: a solenoid directional valve, a throttle valve, a safety valve, and a check valve. Accumulators are installed at ports A1, A2, and A3. The safety valve is installed between ports P1, P2, and T. The solenoid directional valve is located between ports P1 and T. The throttle valve is located between the solenoid directional valve and port P. The check valve is located after port P1 and before ports A1 and A2.

4. The dual-redundant hydraulic four-wheel steering system as described in claim 1, characterized in that, The TSB port of the steering valve assembly is equipped with a pressure sensor, which is connected to a pressure switch via a wire.

5. An unmanned mining dump truck, characterized in that, Includes the dual-redundant hydraulic four-wheel steering system as described in any one of claims 1-4.

6. The dual-redundant hydraulic four-wheel steering method for an unmanned mining dump truck as described in claim 5, characterized in that, include: The plunger pump outputs pressurized oil to the steering valve assembly, which in turn provides pressurized oil to the first flow amplifier and the second flow amplifier. The first and second electro-hydraulic steering valves receive control signals and output pilot pressure oil to the first flow amplifier; the third and fourth electro-hydraulic steering valves receive control signals and output pilot pressure oil to the second flow amplifier. The first flow amplifier controls the steering mechanism of the front axle to move, and the second flow amplifier controls the steering mechanism of the rear axle to move. When the vehicle is moving forward, the first electro-hydraulic steering valve and the second electro-hydraulic steering valve control the first flow amplifier to perform a steering action on the front steering cylinder, making the front wheels of the vehicle the active steering wheels; when the vehicle is moving backward, the third electro-hydraulic steering valve and the fourth electro-hydraulic steering valve control the second flow amplifier to perform a steering action on the rear steering cylinder, making the rear wheels of the vehicle the active steering wheels.

7. The dual-redundant hydraulic four-wheel steering method for an unmanned mining dump truck as described in claim 6, characterized in that, The first and second electro-hydraulic steering valves, under the control of electrical signals, output pilot pressure oil to the first flow amplifier. The outlet CL and outlet CR of the first flow amplifier are connected to the front axle steering cylinder to control the steering mechanism of the front axle. Excess pressure oil returns to the hydraulic oil tank through the HT port of the first flow amplifier and the return oil filter. The third and fourth electro-hydraulic steering valves, under the control of electrical signals, output pilot pressure oil to control the second flow amplifier. The outlet CL and outlet CR of the second flow amplifier are connected to the rear axle steering cylinder to control the steering mechanism of the rear axle. Excess pressure oil returns to the hydraulic oil tank through the return oil filter of the HT port of the second flow amplifier.

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