Unmanned mining dump truck with electric wheels and four-wheel hydraulic steering system

Abstract

The utility model discloses a four-wheel hydraulic steering system which comprises a first electro-hydraulic steering gear, a first flow amplifier, a front axle left steering cylinder, a front axle right steering cylinder, a steering valve set, a plunger pump and a hydraulic oil tank. The plunger pump is used for generating pressure oil and providing pressure and flow for hydraulic oil of the system; the steering valve set is used for providing pressure oil for the first flow amplifier, the first flow amplifier is used for controlling the front axle steering cylinder to act, the first electro-hydraulic steering gear is used for providing pilot control oil for the first flow amplifier, and the front axle steering cylinder serves as an execution device and is used for driving a front wheel steering mechanism of a vehicle to complete steering. The hydraulic oil tank is used for storing hydraulic oil. The utility model further discloses the unmanned mining dump truck with the electric wheels. The two flow amplifiers are controlled through the two electro-hydraulic steering gears to achieve steering actions of the front steering cylinder and the rear steering cylinder, and the steering requirement of two-way driving is met.

Description

Technical Field

[0001] This utility model belongs to the field of electric wheel mining dump trucks, specifically relating to an unmanned electric wheel mining dump truck and a four-wheel hydraulic steering system. 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 bidirectional 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. Utility Model Content

[0004] The purpose of this utility model is to provide an unmanned electric wheel mining dump truck and a four-wheel hydraulic steering system, which controls two flow amplifiers through two electro-hydraulic steering gears to realize the steering action of the front and rear steering cylinders, so as to meet the steering requirements of bidirectional driving.

[0005] To achieve the above objectives, the technical solution used in this utility model is as follows:

[0006] The four-wheel hydraulic steering system includes: a first electro-hydraulic steering gear, a first flow amplifier, a front axle left steering cylinder, a front axle right steering cylinder, a steering valve assembly, a piston pump, and a hydraulic oil tank;

[0007] A plunger pump is used to generate pressurized oil. The inlet is connected to the hydraulic oil tank through a pipeline, and the outlet is connected to the inlet P of the steering valve assembly through a pipeline, providing pressure and flow to the hydraulic oil of the system.

[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, and the working port P1 is connected to the main inlet HP of the first flow amplifier through a pipeline.

[0009] The first flow amplifier is used to control the movement of the front axle steering cylinder. The right working oil port CL is connected to the oil outlet C1 of the front axle left steering cylinder and the oil inlet C2 of the front axle right steering cylinder through pipelines. The left working oil port CR of the first flow amplifier is connected to the oil inlet C2 of the front axle left steering cylinder and the oil outlet C1 of the front axle right steering cylinder through pipelines.

[0010] The first electro-hydraulic steering gear is used to provide pilot control oil to the first flow amplifier. The oil inlet L, oil return R, oil inlet P, oil return T, and oil outlet LS are connected to the L port, R port, P port, T port, and LS port of the first flow amplifier respectively through pipelines.

[0011] The front axle steering cylinder includes a front axle left steering cylinder and a front axle right steering cylinder, which serve as actuators to drive the front wheel steering mechanism of the vehicle to complete steering.

[0012] A hydraulic oil tank is used to store hydraulic oil.

[0013] Furthermore, the working port P2 of the steering valve assembly is connected to the main inlet HP of the second flow amplifier via a pipeline; including:

[0014] The second flow amplifier is used to control the movement of the rear axle steering cylinder. The right working oil port CL is connected to the oil outlet C1 of the rear axle left steering cylinder and the oil inlet C2 of the rear axle right steering cylinder through pipelines. The CR port of the second flow amplifier is connected to the oil inlet C2 of the rear axle left steering cylinder and the oil outlet C1 of the rear axle right steering cylinder through pipelines.

[0015] The second electro-hydraulic steering gear is used to provide pilot control oil to the second flow amplifier. L, R, P, T, and LS are connected to the L port, R, P, T port, and LS port of the second flow amplifier respectively through pipelines.

[0016] The rear axle steering cylinder includes a left rear axle steering cylinder and a right rear axle steering cylinder, which serve as actuators to drive the rear wheel steering mechanism of the vehicle to complete steering.

[0017] Furthermore, the steering hydraulic port AC of the steering valve assembly is connected to an accumulator via a pipeline, which is used to provide pressurized oil for emergency steering of the system.

[0018] Furthermore, the return port T of the steering valve assembly is connected to a first return oil filter via a pipeline, and the first return oil filter is connected to the hydraulic oil tank via a pipeline.

[0019] Furthermore, the steering valve assembly is an integrated valve, including: a solenoid directional valve, a throttle valve, a safety valve, and a check valve. The safety valve is installed between P1, P2, and T; the solenoid directional valve is installed between P1, P2, and T; the throttle valve is installed between the solenoid directional valve and T; and the check valve is installed after P and before P1 and P2.

[0020] Furthermore, the plunger pump is a constant pressure variable pump, with an oil suction filter at the oil inlet and a high pressure filter at the oil outlet.

[0021] Furthermore, the main return port HT of the first flow amplifier is connected to the second return oil filter through a pipeline, and the second return oil filter is connected to the hydraulic oil tank through a pipeline; the main return port HT of the second flow amplifier is connected to the third return oil filter through a pipeline, and the third return oil filter is connected back to the hydraulic oil tank through a pipeline.

[0022] The unmanned electric wheel mining dump truck includes: a front wheel steering mechanism, a rear wheel steering mechanism, and a four-wheel hydraulic steering system. The left and right steering cylinders of the front axle are connected to the front wheel steering mechanism through pipelines, and the left and right steering cylinders of the rear axle are connected to the rear wheel steering mechanism through pipelines.

[0023] The technical effects of this utility model include:

[0024] This invention uses two electro-hydraulic steering gears to control two flow amplifiers, thereby realizing the steering action of the front axle steering cylinder and the rear axle steering cylinder, and meeting the steering requirements for bidirectional driving.

[0025] Two electro-hydraulic steering units (first electro-hydraulic steering unit and second electro-hydraulic steering unit) are used to supply pilot control oil to two flow amplifiers (first flow amplifier and second flow amplifier). The two flow amplifiers control the front axle steering cylinder and the rear axle steering cylinder respectively, ensuring that the steering system can switch actions when the vehicle is traveling in the rear as if it were traveling in the forward direction. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the four-wheel hydraulic steering system of the unmanned electric wheel mining dump truck of this utility model.

[0027] The components include: 1. First electro-hydraulic steering gear; 2. Second electro-hydraulic steering gear; 3. First flow amplifier; 4. Second flow amplifier; 5. Front axle left steering cylinder; 6. Front axle right steering cylinder; 7. Rear axle left steering cylinder; 8. Rear axle right steering cylinder; 9. Steering valve assembly; 9.1. Solenoid directional valve; 9.2. Throttle valve; 9.3. Safety valve; 9.4. Check valve; 10. Accumulator; 11. First return oil filter; 12. High-pressure filter; 13. Piston pump; 14. Suction filter; 15. Second return oil filter; 16. Third return oil filter; 17. Hydraulic oil tank. Detailed Implementation

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] Unless otherwise stated, the term "multiple" means two or more.

[0033] 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.

[0034] 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.

[0035] It should be noted that, unless otherwise specified, the embodiments and features described in the present disclosure can be combined with each other. The following description fully illustrates specific embodiments of the present invention to enable those skilled in the art to practice and reproduce it.

[0036] like Figure 1The diagram shown is a structural schematic of the four-wheel hydraulic steering system of the unmanned electric wheel mining dump truck of this utility model.

[0037] The four-wheel hydraulic steering system of the unmanned electric wheel mining dump truck includes: a first electro-hydraulic steering gear 1, a second electro-hydraulic steering gear 2, a first flow amplifier 3, a second flow amplifier 4, a front axle left steering cylinder 5, a front axle right steering cylinder 6, a rear axle left steering cylinder 7, a rear axle right steering cylinder 8, a steering valve group 9, an accumulator 10, a first return oil filter 11, a high-pressure filter 12, a plunger pump 13, a suction oil filter 14, a second return oil filter 15, and a hydraulic oil tank 17.

[0038] The plunger pump 13 is used to generate pressurized oil. Its inlet is connected to the hydraulic oil tank 17 through a pipeline, and its outlet is connected to the P port (inlet) of the steering valve assembly 9 through a pipeline, so as to provide pressure and flow for the hydraulic oil of the system.

[0039] The steering valve assembly 9 is used to supply pressurized oil to the first flow amplifier 3 and the second flow amplifier 4. The T port (return port) is connected to the oil tank 17 through a pipeline, the P1 port (working port) is connected to the HP port (main inlet port) of the first flow amplifier 3 through a pipeline, and the P2 port (working port) is connected to the HP port (main inlet port) of the second flow amplifier 4 through a pipeline.

[0040] The first flow amplifier 3 is used to control the movement of the front axle steering cylinder. The CL port (right working oil port) is connected to the C1 port (oil outlet) of the front axle left steering cylinder 5 and the C2 port (oil inlet) of the front axle right steering cylinder 6 through pipelines. The CR port (left working oil port) of the first flow amplifier 3 is connected to the C2 port (oil inlet) of the front axle left steering cylinder 5 and the C1 port (oil outlet) of the front axle right steering cylinder 6 through pipelines.

[0041] The second flow amplifier 4 is used to control the operation of the rear axle steering cylinder. The CL port (right working oil port) is connected to the C1 port (oil outlet) of the left rear axle steering cylinder 7 and the C2 port (oil inlet) of the right rear axle steering cylinder 8 through pipelines. The CR port of the second flow amplifier 4 is connected to the C2 port (oil inlet) of the left rear axle steering cylinder 7 and the C1 port (oil outlet) of the right rear axle steering cylinder 8 through pipelines.

[0042] The first electro-hydraulic steering gear 1 is used to provide pilot control oil to the first flow amplifier 3. The L port (oil inlet), R port (oil return port), P port (oil inlet), T port (oil return port), and LS port (oil outlet) are respectively connected to the L port, R port, P port, T port, and LS port of the first flow amplifier 3 through pipelines.

[0043] The second electro-hydraulic steering gear 2 is used to provide pilot control oil to the second flow amplifier 4. The L port (oil inlet), R port (oil return port), P port (oil inlet), T port (oil return port), and LS port (oil outlet) are connected to the L port, R port, P port, T port, and LS port of the second flow amplifier 4 respectively through pipelines.

[0044] Hydraulic oil tank 17 is used for storing hydraulic oil.

[0045] The front axle steering cylinder includes: front axle left steering cylinder 5 and front axle right steering cylinder 6, which serve as actuators to drive the vehicle's front wheel steering mechanism to complete steering;

[0046] The rear axle steering cylinder includes a left rear axle steering cylinder 7 and a right rear axle steering cylinder 8, which serve as actuators to drive the vehicle's rear wheel steering mechanism to complete steering.

[0047] The AC port (steering hydraulic port) of the steering valve assembly 9 is connected to the accumulator 10, which provides the system with emergency steering pressure oil; the T port (return port) is connected to the first return oil filter 11 through a pipeline, and the hydraulic oil returns to the hydraulic oil tank 17 through the first return oil filter 11.

[0048] The steering valve assembly 9 is an integrated valve, containing a safety valve, a solenoid shut-off valve, and a check valve. The steering valve assembly 9 includes: a solenoid directional valve 9.1, a throttle valve 9.2, a safety valve 9.3, and a check valve 9.4. An accumulator 10 is installed at the AC port. The safety valve is installed between ports P1, P2, and T; the solenoid directional valve 9.1 is installed between ports P1, P2, and T; the throttle valve 9.2 is installed between the solenoid directional valve 9.1 and port T; and the check valve 9.4 is installed after port P and before ports P1 and P2.

[0049] The plunger pump 13 is equipped with an oil suction filter 14 at the oil inlet and a high-pressure filter 12 at the oil outlet. The plunger pump 13 is a constant pressure variable pump.

[0050] The HT port (main return port) of the first flow amplifier 3 is connected to the second return oil filter 15 through a pipeline, and the second return oil filter 15 is connected to the hydraulic oil tank 17 through a pipeline.

[0051] The HT port (main return port) of the second flow amplifier 4 is connected to the third return oil filter 16 through a pipeline, and the third return oil filter 16 is connected back to the hydraulic oil tank 17 through a pipeline.

[0052] The hydraulic oil from the first flow amplifier 3, the second flow amplifier 4, and the steering valve assembly 9 returns to the hydraulic oil tank 17 via a separate return oil filter, ensuring the cleanliness of the hydraulic system.

[0053] The four-wheel hydraulic steering method for an unmanned electric wheel mining dump truck comprises the following steps:

[0054] Step 1: The hydraulic oil is converted into high-pressure oil by the plunger pump 13 and enters the steering valve assembly 9;

[0055] An oil suction filter 14 and a high-pressure filter 12 are installed before and after the plunger pump 13. After the pressurized oil enters the steering valve assembly 9, it first passes through a one-way valve 9.4.

[0056] A safety valve 9.4 is installed between the P port and T port of the steering valve assembly 9 to protect the system components from damage caused by excessive pressure; a solenoid directional valve 9.1 is also installed between the P port and T port of the steering valve assembly 9 to ensure that the accumulator pressure is released within a certain period of time after the vehicle stops.

[0057] An accumulator 10 is installed at the AC port of the steering valve assembly 9 to provide pressure and flow to meet the vehicle's emergency steering requirements, while reducing system pressure pulses.

[0058] Step 2: The steering valve assembly 9 supplies pressurized oil to the first flow amplifier 3 and the second flow amplifier 4 respectively;

[0059] Step 3: The first electro-hydraulic steering unit 1 receives control and outputs pilot pressure oil to the first flow amplifier 3. The first flow amplifier 3 drives the front axle steering cylinder to move, and the front axle steering cylinder drives the front wheel steering mechanism of the vehicle to complete the steering.

[0060] The P1 and P2 ports of the steering valve assembly 9 are respectively connected to the HP ports of the first flow amplifier 3 and the second flow amplifier 4 to provide flow. The P, T, L, R and LS ports of the first flow amplifier 3 are respectively connected to the P, T, L, R and LS ports of the first electro-hydraulic steering gear 1. Under the control of the electrical signal (the control port is connected to the steering controller), the first electro-hydraulic steering gear 1 outputs pilot pressure to control whether the first flow amplifier 3 is activated.

[0061] The first flow amplifier 3 outputs pressurized oil to the front axle steering cylinder of the vehicle, which drives the front wheel steering mechanism to complete the steering. The CL port and CR port of the first flow amplifier 3 are connected to the front axle steering cylinder, which controls the steering mechanism of the front axle. The hydraulic oil returns to the hydraulic oil tank 17 through the HT port of the first flow amplifier 3 and the return oil filter 15.

[0062] Step 4: The second electro-hydraulic steering unit 2 receives control and outputs pilot pressure oil to the second control flow amplifier 4. The second control flow amplifier 4 drives the rear axle steering cylinder to move, and the rear axle steering cylinder drives the rear wheel steering mechanism of the vehicle to complete the steering.

[0063] The P, T, L, R, and LS ports of the second flow amplifier 4 are respectively connected to the P, T, L, R, and LS ports of the second electro-hydraulic steering gear 2. The second electro-hydraulic steering gear 2 can output pilot pressure oil to the second control flow amplifier 4 under the control of the electrical signal. The CL and CR ports of the second control flow amplifier 4 are connected to the rear axle steering cylinder. The rear axle steering cylinder controls the steering mechanism of the rear axle. The hydraulic oil returns to the hydraulic oil tank 17 through the HT port of the front axle steering cylinder and the return oil filter 16.

[0064] Example 1: A four-wheel hydraulic steering system for an unmanned electric wheel mining dump truck, comprising: a first electro-hydraulic steering unit 1, a second electro-hydraulic steering unit 2, a first flow amplifier 3, a second flow amplifier 4, a front axle left steering cylinder 5, a front axle right steering cylinder 6, a rear axle left steering cylinder 7, a rear axle right steering cylinder 8, a steering valve assembly 9, an accumulator 10, a piston pump 13, and a hydraulic oil tank 17.

[0065] The plunger pump 13 is a constant pressure variable pump used to generate pressurized oil. The oil inlet is connected to the hydraulic oil tank 17 through a pipeline, and the oil outlet is connected to the P port (oil inlet) of the steering valve group 9 through a pipeline, so as to provide pressure and flow for the hydraulic oil of the system.

[0066] The steering valve assembly 9 supplies pressurized oil to the first flow amplifier 3 and the second flow amplifier 4. The T port (return port) is connected to the oil tank 17 via a pipeline, the P1 port (working port) is connected to the HP port (main inlet port) of the first flow amplifier 3 via a pipeline, and the P2 port (working port) is connected to the HP port (main inlet port) of the second flow amplifier 4 via a pipeline. The steering valve assembly 9 is an integrated valve, internally equipped with a safety valve, a solenoid shut-off valve, and a check valve. The steering valve assembly 9 includes: a solenoid directional valve 9.1, a throttle valve 9.2, a safety valve 9.3, and a check valve 9.4. An accumulator 10 is installed at the AC port. The safety valve is installed between the P1 port, P2 port, and T port; the solenoid directional valve 9.1 is installed between the P1 port, P2 port, and T port; the throttle valve 9.2 is installed between the solenoid directional valve 9.1 and the T port; and the check valve 9.4 is installed after the P port and before the P1 port and P2 port.

[0067] The first flow amplifier 3 is used to control the movement of the front axle steering cylinder. The CL port (right working oil port) is connected to the C1 port (oil outlet) of the front axle left steering cylinder 5 and the C2 port (oil inlet) of the front axle right steering cylinder 6 through pipelines. The CR port (left working oil port) of the first flow amplifier 3 is connected to the C2 port (oil inlet) of the front axle left steering cylinder 5 and the C1 port (oil outlet) of the front axle right steering cylinder 6 through pipelines. The second return oil filter 15 is connected to the hydraulic oil tank 17 through pipelines.

[0068] The second flow amplifier 4 is used to control the operation of the rear axle steering cylinder. The CL port (right working oil port) is connected to the C1 port (oil outlet) of the left rear axle steering cylinder 7 and the C2 port (oil inlet) of the right rear axle steering cylinder 8 through pipelines. The CR port of the second flow amplifier 4 is connected to the C2 port (oil inlet) of the left rear axle steering cylinder 7 and the C1 port (oil outlet) of the right rear axle steering cylinder 8 through pipelines.

[0069] The first electro-hydraulic steering gear 1 is used to provide pilot control oil to the first flow amplifier 3. The L port (oil inlet), R port (oil return port), P port (oil inlet), T port (oil return port), and LS port (oil outlet) are respectively connected to the L port, R port, P port, T port, and LS port of the first flow amplifier 3 through pipelines.

[0070] The second electro-hydraulic steering gear 2 is used to provide pilot control oil to the second flow amplifier 4. The L port (oil inlet), R port (oil return port), P port (oil inlet), T port (oil return port), and LS port (oil outlet) are connected to the L port, R port, P port, T port, and LS port of the second flow amplifier 4 respectively through pipelines.

[0071] Hydraulic oil tank 17 is used for storing hydraulic oil.

[0072] The front axle steering cylinder includes: front axle left steering cylinder 5 and front axle right steering cylinder 6, which serve as actuators to drive the vehicle's front wheel steering mechanism to complete steering;

[0073] The rear axle steering cylinder includes a left rear axle steering cylinder 7 and a right rear axle steering cylinder 8, which serve as actuators to drive the vehicle's rear wheel steering mechanism to complete steering.

[0074] The AC port (steering hydraulic port) of the steering valve assembly 9 is connected to the accumulator 10, which provides the system with pressure oil for emergency steering.

[0075] The four-wheel hydraulic steering method for an unmanned electric wheel mining dump truck comprises the following steps:

[0076] Step 1: Hydraulic oil is converted into high-pressure oil by plunger pump 13 and enters steering valve assembly 9; after entering steering valve assembly 9, the pressurized oil first passes through a check valve 9.4; a safety valve 9.4 is installed between the P port and T port of steering valve assembly 9 to protect system components from damage due to excessive pressure; a solenoid directional valve 9.1 is also installed between the P port and T port of steering valve assembly 9 to ensure that the accumulator pressure is released within a certain period of time after stopping; an accumulator 10 is installed at the AC port of steering valve assembly 9 to provide pressure and flow to meet the emergency steering requirements of the vehicle, while reducing system pressure pulses;

[0077] Step 2: The steering valve assembly 9 supplies pressurized oil to the first flow amplifier 3 and the second flow amplifier 4 respectively;

[0078] Step 3: The first electro-hydraulic steering unit 1 receives control and outputs pilot pressure oil to the first flow amplifier 3. The first flow amplifier 3 drives the front axle steering cylinder to actuate, and the front axle steering cylinder drives the front wheel steering mechanism of the vehicle to complete the steering. The P1 port and P2 port of the steering valve group 9 are respectively connected to the HP port of the first flow amplifier 3 and the second flow amplifier 4 to provide flow. The P port, T port, L port, R port, and LS port of the first flow amplifier 3 are respectively connected to the P port, T port, L port, R port, and LS port of the first electro-hydraulic steering unit 1. Under the control of the electrical signal (the control port is connected to the steering controller), the first electro-hydraulic steering unit 1 outputs pilot pressure to control whether the first flow amplifier 3 actuates. The hydraulic oil returns to the hydraulic oil tank 17 through the HT port of the first flow amplifier 3.

[0079] Step 4: The second electro-hydraulic steering unit 2 receives control and outputs pilot pressure oil to the second control flow amplifier 4. The second control flow amplifier 4 drives the rear axle steering cylinder to move, and the rear axle steering cylinder drives the rear wheel steering mechanism of the vehicle to complete the steering. The P port, T port, L port, R port, and LS port of the second flow amplifier 4 are respectively connected to the P port, T port, L port, R port, and LS port of the second electro-hydraulic steering unit 2. The second electro-hydraulic steering unit 2 can output pilot pressure oil to the second control flow amplifier 4 under the control of the electrical signal. The CL and CR ports of the second control flow amplifier 4 are connected to the rear axle steering cylinder. The rear axle steering cylinder controls the steering mechanism of the rear axle to move. The hydraulic oil returns to the hydraulic oil tank 17 through the HT port of the front axle steering cylinder.

[0080] Example 2: Based on Example 1, a first return oil filter 11, a high-pressure filter 12, a second return oil filter 15, and a suction oil filter 14 are added.

[0081] The plunger pump 13 is a constant pressure variable pump used to generate pressurized oil. The oil inlet is connected to the hydraulic oil tank 17 through a pipeline, and the oil outlet is connected to the P port (oil inlet) of the steering valve group 9 through a pipeline to provide pressure and flow for the hydraulic oil of the system. The oil inlet of the plunger pump 13 is equipped with a suction filter 14, and the oil outlet is equipped with a high pressure filter 12.

[0082] The steering valve assembly 9 supplies pressurized oil to the first flow amplifier 3 and the second flow amplifier 4. The T port (return port) is connected to the oil tank 17 via a pipeline, the P1 port (working port) is connected to the HP port (main inlet port) of the first flow amplifier 3 via a pipeline, and the P2 port (working port) is connected to the HP port (main inlet port) of the second flow amplifier 4 via a pipeline. The steering valve assembly 9 is an integrated valve, internally equipped with a safety valve, a solenoid shut-off valve, and a check valve. The steering valve assembly 9 includes: a solenoid directional valve 9.1, a throttle valve 9.2, a safety valve 9.3, and a check valve 9.4. An accumulator 10 is installed at the AC port. The safety valve is installed between the P1 port, P2 port, and T port; the solenoid directional valve 9.1 is installed between the P1 port, P2 port, and T port; the throttle valve 9.2 is installed between the solenoid directional valve 9.1 and the T port; and the check valve 9.4 is installed after the P port and before the P1 port and P2 port.

[0083] The first flow amplifier 3 is used to control the movement of the front axle steering cylinder. Its CL port (right working port) is connected to the C1 port (outlet) of the left front axle steering cylinder 5 and the C2 port (inlet) of the right front axle steering cylinder 6 via pipelines. The CR port (left working port) of the first flow amplifier 3 is connected to the C2 port (inlet) of the left front axle steering cylinder 5 and the C1 port (outlet) of the right front axle steering cylinder 6 via pipelines. The HT port (main return port) of the first flow amplifier 3 is connected to the second return oil filter 15 via pipelines. The second return oil filter 15 is connected to the hydraulic oil tank 17 via pipelines. The hydraulic oil T ports of the first flow amplifier 3, the second flow amplifier 4, and the steering valve assembly 9 return to the hydraulic oil tank 17 through separate return oil filters to ensure the cleanliness of the hydraulic system.

[0084] The second flow amplifier 4 is used to control the movement of the rear axle steering cylinder. The CL port (right working oil port) is connected to the C1 port (oil outlet) of the left rear axle steering cylinder 7 and the C2 port (oil inlet) of the right rear axle steering cylinder 8 through pipelines. The CR port of the second flow amplifier 4 is connected to the C2 port (oil inlet) of the left rear axle steering cylinder 7 and the C1 port (oil outlet) of the right rear axle steering cylinder 8 through pipelines. The HT port (main return oil port) of the second flow amplifier 4 is connected to the third return oil filter 16 through pipelines. The third return oil filter 16 is connected back to the hydraulic oil tank 17 through pipelines.

[0085] The first electro-hydraulic steering gear 1 is used to provide pilot control oil to the first flow amplifier 3. The L port (oil inlet), R port (oil return port), P port (oil inlet), T port (oil return port), and LS port (oil outlet) are respectively connected to the L port, R port, P port, T port, and LS port of the first flow amplifier 3 through pipelines.

[0086] The second electro-hydraulic steering gear 2 is used to provide pilot control oil to the second flow amplifier 4. The L port (oil inlet), R port (oil return port), P port (oil inlet), T port (oil return port), and LS port (oil outlet) are connected to the L port, R port, P port, T port, and LS port of the second flow amplifier 4 respectively through pipelines.

[0087] Hydraulic oil tank 17 is used for storing hydraulic oil.

[0088] The front axle steering cylinder includes: front axle left steering cylinder 5 and front axle right steering cylinder 6, which serve as actuators to drive the vehicle's front wheel steering mechanism to complete steering;

[0089] The rear axle steering cylinder includes a left rear axle steering cylinder 7 and a right rear axle steering cylinder 8, which serve as actuators to drive the vehicle's rear wheel steering mechanism to complete steering.

[0090] The AC port (steering hydraulic port) of the steering valve assembly 9 is connected to the accumulator 10, which provides the system with emergency steering pressure oil; the T port (return port) is connected to the first return oil filter 11 through a pipeline, and the hydraulic oil returns to the hydraulic oil tank 17 through the first return oil filter 11.

[0091] The four-wheel hydraulic steering method for an unmanned electric wheel mining dump truck comprises the following steps:

[0092] Step 1: Hydraulic oil is converted into high-pressure oil by plunger pump 13 and enters steering valve assembly 9; an oil suction filter 14 and a high-pressure filter 12 are installed before and after plunger pump 13. After the pressurized oil enters steering valve assembly 9, it first passes through a one-way valve 9.4; a safety valve 9.4 is installed between the P port and T port of steering valve assembly 9 to protect system components from damage caused by excessive pressure; a solenoid directional valve 9.1 is also installed between the P port and T port of steering valve assembly 9 to ensure that the accumulator pressure is released within a certain period of time after stopping; an accumulator 10 is installed at the AC port of steering valve assembly 9 to provide pressure and flow to meet the emergency steering requirements of the vehicle, while reducing system pressure pulses;

[0093] Step 2: The steering valve assembly 9 supplies pressurized oil to the first flow amplifier 3 and the second flow amplifier 4 respectively;

[0094] Step 3: The first electro-hydraulic steering unit 1 receives control and outputs pilot pressure oil to the first flow amplifier 3. The first flow amplifier 3 drives the front axle steering cylinder to actuate, and the front axle steering cylinder drives the front wheel steering mechanism of the vehicle to complete the steering. The P1 port and P2 port of the steering valve group 9 are respectively connected to the HP port of the first flow amplifier 3 and the second flow amplifier 4 to provide flow. The P port, T port, L port, R port and LS port of the first flow amplifier 3 are respectively connected to the P port, T port, L port, R port and LS port of the first electro-hydraulic steering unit 1. Under the control of the electrical signal (the control port is connected to the steering controller), the first electro-hydraulic steering unit 1 outputs pilot pressure to control whether the first flow amplifier 3 actuates. The hydraulic oil returns to the hydraulic oil tank 17 through the HT port of the first flow amplifier 3 and the return oil filter 15.

[0095] Step 4: The second electro-hydraulic steering unit 2 receives control and outputs pilot pressure oil to the second control flow amplifier 4. The second control flow amplifier 4 drives the rear axle steering cylinder to move, and the rear axle steering cylinder drives the rear wheel steering mechanism of the vehicle to complete the steering. The P port, T port, L port, R port, and LS port of the second flow amplifier 4 are respectively connected to the P port, T port, L port, R port, and LS port of the second electro-hydraulic steering unit 2. The second electro-hydraulic steering unit 2 can output pilot pressure oil to the second control flow amplifier 4 under the control of the electrical signal. The CL and CR ports of the second control flow amplifier 4 are connected to the rear axle steering cylinder. The rear axle steering cylinder controls the steering mechanism of the rear axle to move. The hydraulic oil returns to the hydraulic oil tank 17 through the HT port of the front axle steering cylinder and the return oil filter 16.

[0096] The terminology used in this invention is descriptive and exemplary, and not restrictive. Since this invention can be embodied in various forms without departing from the spirit or essence of the technical solution, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims. Therefore, all variations and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A four-wheel hydraulic steering system, characterized in that, include: First electro-hydraulic steering gear, first flow amplifier, front axle left steering cylinder, front axle right steering cylinder, steering valve assembly, piston pump, hydraulic oil tank; A plunger pump is used to generate pressurized oil. The inlet is connected to the hydraulic oil tank through a pipeline, and the outlet is connected to the inlet P of the steering valve assembly through a pipeline, providing pressure and flow to the hydraulic oil of the system. 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, and the working port P1 is connected to the main inlet HP of the first flow amplifier through a pipeline. The first flow amplifier is used to control the movement of the front axle steering cylinder. The right working oil port CL is connected to the oil outlet C1 of the front axle left steering cylinder and the oil inlet C2 of the front axle right steering cylinder through pipelines. The left working oil port CR of the first flow amplifier is connected to the oil inlet C2 of the front axle left steering cylinder and the oil outlet C1 of the front axle right steering cylinder through pipelines. The first electro-hydraulic steering gear is used to provide pilot control oil to the first flow amplifier. The oil inlet L, oil return R, oil inlet P, oil return T, and oil outlet LS are connected to the L port, R port, P port, T port, and LS port of the first flow amplifier respectively through pipelines. The front axle steering cylinder includes a front axle left steering cylinder and a front axle right steering cylinder, which serve as actuators to drive the front wheel steering mechanism of the vehicle to complete steering. A hydraulic oil tank is used to store hydraulic oil.

2. The four-wheel hydraulic steering system as described in claim 1, characterized in that, The working port P2 of the steering valve assembly is connected to the main inlet HP of the second flow amplifier via a pipeline; including: The second flow amplifier is used to control the movement of the rear axle steering cylinder. The right working oil port CL is connected to the oil outlet C1 of the rear axle left steering cylinder and the oil inlet C2 of the rear axle right steering cylinder through pipelines. The CR port of the second flow amplifier is connected to the oil inlet C2 of the rear axle left steering cylinder and the oil outlet C1 of the rear axle right steering cylinder through pipelines. The second electro-hydraulic steering gear is used to provide pilot control oil to the second flow amplifier. The oil inlet L, oil return R, oil inlet P, oil return T, and oil outlet LS are connected to the L port, R port, P port, T port, and LS port of the second flow amplifier respectively through pipelines. The rear axle steering cylinder includes a left rear axle steering cylinder and a right rear axle steering cylinder, which serve as actuators to drive the rear wheel steering mechanism of the vehicle to complete steering.

3. The four-wheel hydraulic steering system as described in claim 1, characterized in that, The steering hydraulic port AC of the steering valve assembly is connected to an accumulator via a pipeline. The accumulator is used to provide pressurized oil for emergency steering of the system.

4. The four-wheel hydraulic steering system as described in claim 1, characterized in that, The return port T of the steering valve assembly is connected to the first return oil filter via a pipeline, and the first return oil filter is connected to the hydraulic oil tank via a pipeline.

5. The four-wheel hydraulic steering system as described in claim 2, 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. The safety valve is installed between P1, P2, and T; the solenoid directional valve is installed between P1, P2, and T; the throttle valve is installed between the solenoid directional valve and T; and the check valve is installed after P and before P1 and P2.

6. The four-wheel hydraulic steering system as described in claim 1, characterized in that, The plunger pump is a constant pressure variable pump. The plunger pump is equipped with an oil suction filter at the oil inlet and a high pressure filter at the oil outlet.

7. The four-wheel hydraulic steering system as described in claim 1, characterized in that, The main return port HT of the first flow amplifier is connected to the second return oil filter through a pipeline, and the second return oil filter is connected to the hydraulic oil tank through a pipeline; the main return port HT of the second flow amplifier is connected to the third return oil filter through a pipeline, and the third return oil filter is connected back to the hydraulic oil tank through a pipeline.

8. An unmanned electric wheel mining dump truck, comprising: The front wheel steering mechanism and the rear wheel steering mechanism are characterized in that they include the four-wheel hydraulic steering system as described in any one of claims 1-7, wherein the front axle left steering cylinder and the front axle right steering cylinder are respectively connected to the front wheel steering mechanism through pipelines, and the rear axle left steering cylinder and the rear axle right steering cylinder are respectively connected to the rear wheel steering mechanism through pipelines.

Images