Synchronous steering system for front and rear wheels of unmanned mine car and control method

Abstract

The invention discloses an unmanned mine car front and rear wheel synchronous steering system which comprises a car frame, a front steering axle and a rear steering axle, and the front steering axle and the rear steering axle are installed on a car and control steering through a steering system. The steering system comprises a front axle working cylinder, a front axle driven cylinder, a rear axle working cylinder and a rear axle driven cylinder, the front axle working cylinder and the front axle driven cylinder control front wheels of a vehicle to rotate, the rear axle working cylinder and the rear axle driven cylinder control rear wheels of the vehicle to rotate, and cavities of the front axle working cylinder and the rear axle working cylinder are communicated with a working port A and a working port B of a three-position four-way reversing valve through pipelines respectively. Cavities of the front axle driven cylinder and the rear axle driven cylinder are communicated through a valveless rigid connecting pipeline to form a rigid series oil way, and in the rigid series oil way, the amount of oil discharged by the front wheel working cylinder and the front axle driven cylinder is equal to the amount of oil received by the rear wheel working cylinder and the rear axle driven cylinder. Mechanical hydraulic synchronization of steering angles of front and rear wheels of the vehicle is realized, delay and fault risks of dependence on sensors are eliminated, and high-reliability rigid synchronization is realized.

Description

Technical Field

[0001] This invention relates to the field of vehicle engineering, specifically to a synchronous steering system and control method for the front and rear wheels of an unmanned mining truck. Background Technology

[0002] In existing technologies, vehicles using hydraulic steering only have a steering system installed on the front or rear axle, controlling only the front or rear wheels, resulting in a relatively large turning radius. However, unmanned mining trucks need to navigate narrow tunnels, requiring a smaller turning radius for steering. Therefore, steering systems need to be installed on both the front and rear axles, with the front and rear wheels steering synchronously in opposite directions.

[0003] If both the front and rear wheels need to steer, they are typically driven by independently controlled hydraulic cylinders. This method requires a complex electronic control unit (ECU), multiple high-precision steering angle sensors, and sophisticated control algorithms to achieve synchronization between the front and rear wheels. It suffers from drawbacks such as high cost, high system complexity, latency, susceptibility to electromagnetic interference, and sensor malfunctions leading to synchronization failure. Maintaining precise synchronization is extremely difficult, especially when there are leaks or time differences in the response of the hydraulic system, which can negatively impact vehicle tracking, cornering stability, and cause severe tire wear. Summary of the Invention

[0004] This invention proposes a synchronous steering system for the front and rear wheels of an unmanned mining truck. By designing a hydraulic circuit, the mechanical hydraulic synchronization of the steering angles of the front and rear wheels is forcibly achieved, completely eliminating the delay and failure risk of the electronic control system and its dependent sensors, and realizing highly reliable rigid synchronization.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: a synchronous steering system for the front and rear wheels of an unmanned mining truck, comprising a frame and a front steering axle and a rear steering axle mounted on the vehicle. The front steering axle and the rear steering axle are controlled by a steering system. The steering system includes a pair of hydraulic cylinders with piston rods extending in opposite directions: a front axle working cylinder and a front axle driven cylinder, a rear axle working cylinder and a rear axle driven cylinder, which respectively control the rotation of the front and rear wheels of the vehicle. The front axle working cylinder and the rear axle working cylinder, as well as the front axle driven cylinder and the rear axle driven cylinder, are mounted diagonally on the frame. The chambers of the front axle working cylinder and the rear axle working cylinder are respectively connected to the working port A and the working port B of a three-position four-way directional valve through pipelines. The chambers of the front axle driven cylinder and the rear axle driven cylinder are connected by a valveless rigid connection pipeline to form a rigid series oil circuit. The oil inlet P of the three-position four-way directional valve is connected to the oil tank through a hydraulic pump, and the oil outlet T is connected to the oil tank. The pair of hydraulic cylinders is cylinder A and cylinder B of a double-acting hydraulic cylinder, or the piston rods of the pair of hydraulic cylinders are interlocked by a rigid connecting rod.

[0006] Preferably, in a rigid series oil circuit, the amount of oil discharged from the front wheel working cylinder and the front axle driven cylinder is equal to the amount of oil received by the rear wheel working cylinder and the rear axle driven cylinder.

[0007] Preferably, the oil inlet P is also connected to a branch, and an overflow valve is connected in series on the branch.

[0008] Preferably, the front axle working cylinder, the front axle driven cylinder, the rear axle working cylinder, and the rear axle driven cylinder are all single-chamber hydraulic cylinders.

[0009] Preferably, the steering system is installed on the side of the front and rear steering axles facing each other, or on the side of the front and rear steering axles facing away from each other. Wheel hubs are also symmetrically provided on both sides of the front and rear steering axles. A steering knuckle arm is installed on the side of the wheel hub closest to the front / rear steering axle. The piston rods of the front axle working cylinder and the front axle driven cylinder on the front steering axle and the piston rods of the rear axle working cylinder and the rear axle driven cylinder on the rear steering axle are respectively connected to one end of one of the steering knuckle arms in the four corner directions of the frame through steering tie rods. The other end of the steering knuckle arm is hinged to the frame body through a rotary joint structure.

[0010] Preferably, when the cylinder pair is designed such that the piston rods of the cylinder pair are interlocked by a rigid connecting rod, the extension lines of the steering tie rods intersect each other at an angle, and the end of the steering tie rod near the steering knuckle arm is connected by a connecting rod.

[0011] The control method for the synchronous steering system of the front and rear wheels of an unmanned mining truck includes the following steps: S1. Input steering commands by manipulating the chassis; S2. When receiving a left / right turn command, the oil pump inlet P is connected to the working port A, and the working port B is connected to the return port T. Oil enters the front axle working cylinder, and the piston rods of the front axle working cylinder and the front axle driven cylinder move in opposite directions. The front axle driven cylinder and the rear axle driven cylinder are volume interlocked. The piston rods of the rear axle working cylinder and the rear axle driven cylinder move in opposite directions, and the rear axle working cylinder discharges oil to the oil tank. S3. When receiving a right / left turn command, the oil pump inlet P is connected to the working port B, and the working port A is connected to the return port T. Oil enters the rear axle working cylinder, and the piston rods of the rear axle working cylinder and the rear axle driven cylinder move in opposite directions. The rear axle driven cylinder and the front axle driven cylinder are volume-interlocked, and the piston rods of the front axle working cylinder and the front axle driven cylinder move in opposite directions. The front axle working cylinder discharges oil to the oil tank.

[0012] Beneficial effects: By designing a hydraulic circuit, mechanical-hydraulic synchronization of the steering angles of the front and rear wheels is forcibly achieved. There is no control loop delay, resulting in high precision. Furthermore, the pure mechanical-hydraulic connection provides strong resistance to electromagnetic interference and stable performance in harsh environments, reducing system complexity and manufacturing and maintenance costs. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the connection when the wheel of the present invention is not rotating; Figure 2 This is a schematic diagram of the invention when turning left; Figure 3 This is a schematic diagram of the invention when turning right; Figure 4 This is a schematic diagram of the overall system structure; Figure 5 This is a schematic diagram of the rear axle steering system. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0015] Example 1 A synchronous steering system for the front and rear wheels of an unmanned mining truck includes a frame and front and rear steering axles mounted on the unmanned mining truck. The front and rear steering axles are controlled by a steering system, such as... Figure 1 As shown, the steering system includes an oil tank 1, a hydraulic pump 2, an overflow valve 3, a three-position four-way directional valve 4, a front axle working cylinder 5 and a front axle driven cylinder 6, a rear axle working cylinder 7 and a rear axle driven cylinder 8.

[0016] Both the front axle driven cylinder 6 and the rear axle driven cylinder 8 are single-chamber hydraulic cylinders. The chambers of the front axle driven cylinder 6 and the rear axle driven cylinder 8 are connected by a valveless rigid connecting pipeline. Both the front axle working cylinder 5 and the rear axle working cylinder 7 are single-chamber hydraulic cylinders. The piston rods of the front axle working cylinder 5 and the front axle driven cylinder 6 are interlocked by a rigid connecting rod. The piston rods of the rear axle working cylinder 7 and the rear axle driven cylinder 8 are also interlocked by a rigid connecting rod.

[0017] The chambers of the front axle working cylinder 5 and the rear axle working cylinder 7 are respectively connected to the working port A and working port B of the three-position four-way directional valve 4 through pipelines. The oil inlet P of the three-position four-way directional valve 4 is connected to the oil tank 1 through the hydraulic pump 2. The oil inlet P is also connected to a branch line, on which an overflow valve 3 is connected in series. The oil outlet T of the three-position four-way directional valve 4 is connected to the oil tank 1.

[0018] Preferably, the chambers of the front axle driven cylinder 6 and the rear axle driven cylinder 8 are connected by a valveless rigid connecting pipeline to form a rigid series oil circuit. In the rigid series oil circuit, the amount of oil discharged from the front wheel working cylinder and the front axle driven cylinder 6 must be equal to the amount of oil received by the rear wheel working cylinder and the rear axle driven cylinder 8.

[0019] like Figure 2 and Figure 3 and Figure 4As shown, the steering system is installed on the side of the front steering axle and the rear steering axle that are directly opposite each other. Wheel hubs 15 are also symmetrically provided on both sides of the front steering axle and the rear steering axle. A steering knuckle arm 14 is installed on the side of the wheel hub 15 near the front steering axle / rear steering axle. The piston rods of the front axle working cylinder 5 and the front axle driven cylinder 6 on the front steering axle and the piston rods of the rear axle working cylinder 7 and the rear axle driven cylinder 8 on the rear steering axle are respectively connected to one end of one of the steering knuckle arms 14 in the four corner directions of the frame through the steering tie rod 13. The other end of the steering knuckle arm 14 is hinged to the frame body through a rotary joint structure.

[0020] Furthermore, the front axle working cylinder 5 and the front axle driven cylinder 6 control the rotation of the vehicle's front wheels, wherein the front axle driven cylinder 6 controls the rotation of the vehicle's left front wheel 9, and the front axle working cylinder 5 controls the rotation of the vehicle's right front wheel 10; the rear axle working cylinder 7 and the rear axle driven cylinder 8 control the rotation of the vehicle's rear wheels, wherein the rear axle working cylinder 7 controls the rotation of the vehicle's left rear wheel 11, and the rear axle driven cylinder 8 controls the rotation of the vehicle's right rear wheel 12; as... Figure 5 The front wheels of the vehicle shown are linked by mechanical linkages, and the rear wheels are linked by mechanical linkages. The extensions of the steering tie rods 13 intersect each other at an angle, and the end of the steering tie rods 13 near the steering knuckle arm 14 is connected by a link 16.

[0021] Furthermore, both the front axle driven cylinder 6 and the rear axle driven cylinder 8 are single-chamber hydraulic cylinders. The chambers of the front axle driven cylinder 6 and the rear axle driven cylinder 8 are connected by a valveless rigid connection pipeline. Both the front axle working cylinder 5 and the rear axle working cylinder 7 are single-chamber hydraulic cylinders. The chambers of the front axle working cylinder 5 and the rear axle working cylinder 7 are respectively connected to the working port A and working port B of the three-position four-way directional valve 4 through pipelines. The oil inlet P and oil return T of the three-position four-way directional valve 4 are respectively connected to the hydraulic pump 2 and the oil tank 1.

[0022] When the control system issues a left turn command, the oil pump inlet P connects to the working port A, and the working port B connects to the return port T, thus supplying oil to the front axle working cylinder 5. Figure 2 As shown, the right front wheel 10 turns to the left, and the left front wheel 9 turns to the left in linkage. The front axle driven cylinder 6 and the rear axle driven cylinder 8 are volume-locked. The front axle driven cylinder 6 discharges oil to the rear axle driven cylinder 8. The right rear wheel 12 turns to the right, and the left rear wheel 11 turns to the right in linkage. The rear axle working cylinder 7 discharges oil to the oil tank 1.

[0023] When the control system issues a right turn command, the oil pump inlet P connects to the working port B, and the working port A connects to the return port T, allowing oil to enter the rear axle working cylinder 7 of the vehicle. Figure 3 As shown, the left rear wheel 11 turns left and the right rear wheel 12 turns left in linkage. The rear axle driven cylinder 8 and the front axle driven cylinder 6 are volume-locked. The front axle driven cylinder 6 discharges oil to the rear axle driven cylinder 8. The left front wheel 9 turns right and left in linkage. The right front wheel 10 turns right in linkage. The front axle working cylinder 5 discharges oil to the oil tank 1.

[0024] Preferably, the rotary joint structure includes a universal joint bearing and a flange-type sealing seat. The bearing dynamic load coefficient is not less than 4.0, and the allowable rotation angle is ±30°. The universal joint bearing assembly of the rotary joint structure adopts a double-row tapered roller bearing with an axial load capacity of not less than 200kN and a radial swing angle of ±25°.

[0025] The control method for the synchronous steering system of the front and rear wheels of an unmanned mining truck includes the following steps: S1. Input steering commands by manipulating the chassis; S2. When receiving a left / right turn command, the oil pump inlet P is connected to the working port A, and the working port B is connected to the return port T. Oil enters the front axle working cylinder 5, and the piston rods of the front axle working cylinder 5 and the front axle driven cylinder 6 move in opposite directions. The front axle driven cylinder 6 and the rear axle driven cylinder 8 are volume-interlocked. The piston rods of the rear axle working cylinder 7 and the rear axle driven cylinder 8 move in opposite directions. The rear axle working cylinder 7 discharges oil to the oil tank 1. S3. When receiving a right / left turn command, the oil pump inlet P is connected to the working port B, and the working port A is connected to the return port T. Oil enters the rear axle working cylinder 7, and the piston rods of the rear axle working cylinder 7 and the rear axle driven cylinder 8 move in opposite directions. The rear axle driven cylinder 8 is volumetrically interlocked with the front axle driven cylinder 6. The piston rods of the front axle working cylinder 5 and the front axle driven cylinder 6 move in opposite directions, and the front axle working cylinder 5 discharges oil to the oil tank 1.

[0026] As an alternative to Embodiment 1, the aforementioned steering system is installed on the opposite sides of the front and rear steering axles, unlike... Figure 2 and Figure 3 When oil is introduced into the front axle working cylinder 5 of the vehicle, the right front wheel 10 turns to the right and the left rear wheel 11 turns to the left. When oil is introduced into the rear axle working cylinder 7 of the vehicle, the left rear wheel 11 turns to the right and the right front wheel 10 turns to the left.

[0027] As an alternative to Embodiment 1, the front axle working cylinder 5 and the front axle driven cylinder 6 are cylinders A and B of a double-acting hydraulic cylinder, and the rear axle working cylinder 7 and the rear axle driven cylinder 8 are cylinders A and B of a double-acting hydraulic cylinder, eliminating the need for connecting rods 16 between the two front wheels and the two rear wheels.

[0028] This invention achieves forced mechanical synchronization of the steering angles of the front and rear wheels through a series-connected double-acting hydraulic cylinder, eliminating the need for external sensors and electronic control systems.

[0029] While the specific embodiments of this disclosure have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of this disclosure. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of this disclosure are still within the scope of protection of this disclosure.

Claims

1. A front and rear wheel synchronous steering system for unmanned mine vehicles, comprising a vehicle frame and a front steering axle and a rear steering axle mounted on the vehicle, the front steering axle and the rear steering axle being controlled to steer by a steering system, characterized in that, The turning system comprises a pair of oil cylinders with opposite piston rod extension directions: front axle working cylinder (5) and front axle driven cylinder (6), rear axle working cylinder (7) and rear axle driven cylinder (8), which control the rotation of the front wheels and the rear wheels of the vehicle respectively, the front axle working cylinder (5) and the rear axle working cylinder (7), the front axle driven cylinder (6) and the rear axle driven cylinder (8) are installed on the opposite corners of the vehicle frame, the chambers of the front axle working cylinder (5) and the rear axle working cylinder (7) are connected through pipelines to the working port A and the working port B of the three-position four-way directional valve (4) respectively, the chambers of the front axle driven cylinder (6) and the rear axle driven cylinder (8) are connected through a valveless rigid connection pipeline to form a rigid series oil circuit, the oil inlet P of the three-position four-way directional valve (4) is connected to the oil tank (1) through the hydraulic pump (2), and the oil outlet T is connected to the oil tank (1), the pair of oil cylinders are A cylinder and B cylinder of a double-acting hydraulic cylinder, or the piston rods of the pair of oil cylinders are connected through a rigid connecting rod.

2. The front and rear wheel synchronous steering system of an unmanned mine car according to claim 1, characterized in that, In the rigid series oil circuit, the oil amount discharged from the front wheel working cylinder and the front axle driven cylinder (6) is equal to the oil amount received by the rear wheel working cylinder and the rear axle driven cylinder (8).

3. The front and rear wheel synchronous steering system of an unmanned mine car according to claim 1, characterized in that, The oil inlet P is also connected to a branch circuit, and an overflow valve (3) is connected in series on the branch circuit.

4. The front and rear wheel synchronous steering system of an unmanned mine car according to claim 1, characterized in that, The front axle working cylinder (5), the front axle driven cylinder (6), the rear axle working cylinder (7) and the rear axle driven cylinder (8) are all single-chamber hydraulic cylinders.

5. The front and rear wheel synchronous steering system of an unmanned mine car according to claim 1, characterized in that, The front turning axle and the rear turning axle are installed with the turning system on the side opposite to each other, or the front turning axle and the rear turning axle are installed with the turning system on the side away from each other, and the front turning axle and the rear turning axle are also symmetrically provided with wheel hubs (15) on both sides, the wheel hubs (15) are installed with steering knuckle arms (14) on the side close to the front turning axle / rear turning axle, the piston rods of the front axle working cylinder (5) and the front axle driven cylinder (6) on the front turning axle and the piston rods of the rear axle working cylinder (7) and the rear axle driven cylinder (8) on the rear turning axle are respectively connected to one end of a steering knuckle arm (14) in the four-corner direction of the vehicle frame through a steering drag link (13), and the other end of the steering knuckle arm (14) is hinged to the main body of the vehicle frame through a rotary pair structure.

6. The front and rear wheel synchronous steering system of an unmanned mine car according to claim 5, characterized in that, When the pair of oil cylinders is designed as a pair of oil cylinders with piston rods connected through a rigid connecting rod, the extension lines of the steering drag links (13) are angularly crossed with each other, and one end of the steering drag link (13) close to the steering knuckle arm (14) is connected through a connecting rod (16).

7. A control method of the front and rear wheel synchronous steering system of the unmanned mine car according to any one of claims 1-6, characterized in that, The method comprises the following steps: S1. Operate the chassis to input a steering instruction; S2. When receiving a left / right steering instruction, the oil pump oil inlet P is connected to the working port A, the working port B is connected to the oil return port T, the front axle working cylinder (5) is filled with oil, the piston rods of the front axle working cylinder (5) and the front axle driven cylinder (6) move in opposite directions, the front axle driven cylinder (6) and the rear axle driven cylinder (8) are volume-locked, the piston rods of the rear axle working cylinder (7) and the rear axle driven cylinder (8) move in opposite directions, and the rear axle working cylinder (7) discharges oil to the oil tank (1). S3. When receiving right / left steering instruction, the oil pump inlet P is connected with the working port B, the working port A is connected with the return port T, the rear axle working cylinder (7) of the vehicle is filled with oil, the piston rod of the rear axle working cylinder (7) and the rear axle driven cylinder (8) moves in the opposite direction, the rear axle driven cylinder (8) is volume interlocked with the front axle driven cylinder (6), the piston rod of the front axle working cylinder (5) and the front axle driven cylinder (6) moves in the opposite direction, and the front axle working cylinder (5) discharges oil to the oil tank (1).

8. The front and rear wheel synchronous steering system of an unmanned mine car according to claim 1, characterized in that, When the vehicle turns left, the oil pump inlet P is connected with the working port A, the working port B is connected with the return port T, the front axle working cylinder (5) of the vehicle is filled with oil, the right front wheel (10) turns left, the left front wheel (9) turns left linkage, the front axle driven cylinder (6) is volume interlocked with the rear axle driven cylinder (8), the front axle driven cylinder (6) discharges oil to the rear axle driven cylinder (8), the right rear wheel (12) turns right, the left rear wheel (11) turns right linkage, and the rear axle working cylinder (7) discharges oil to the oil tank (1).

9. The front and rear wheel synchronous steering system of an unmanned mine car according to claim 1, characterized in that, When the vehicle turns right, the oil pump inlet P is connected with the working port B, the working port A is connected with the return port T, the rear axle working cylinder (7) of the vehicle is filled with oil, the left rear wheel (11) turns left, the right rear wheel (12) turns left linkage, the rear axle driven cylinder (8) is volume interlocked with the front axle driven cylinder (6), the front axle driven cylinder (6) discharges oil to the rear axle driven cylinder (8), the left front wheel (9) turns right, the right front wheel (10) turns right linkage, and the front axle working cylinder (5) discharges oil to the oil tank (1).

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