A front wheel steering device and control method for a grader

Abstract

This invention relates to a front wheel steering device and control method for a grader. The steering device includes a front wheel structure, which is driven and steered by an electric cylinder. The electric cylinder is driven by a power control system, which includes a handle, a steering wheel, a first controller, a second controller, an engine, a generator, a rectifier, an inverter, and a vehicle speed controller. The first controller processes the received signals from the handle or steering wheel, the vehicle speed sensor, and the electric cylinder displacement sensor, and sends them to the second controller. The second controller controls the inverter to output a corresponding current based on the signal output by the first controller. The inverter outputs current to the electric cylinder, and upon receiving the current signal, the electric cylinder drives and steers the front wheel structure. This optimizes the front wheel steering operation of the grader, improves the predictability, comfort, and safety of the front wheel steering, increases work efficiency, and reduces safety hazards.

Description

Technical Field

[0001] This invention relates to the field of grader technology, specifically to a grader front wheel steering device and control method. Background Technology

[0002] In existing technology, the front wheel steering of graders is driven by a system consisting of a hydraulic pump, hydraulic valve, and hydraulic cylinder. Due to the unavoidable internal leakage of hydraulic components and the compressibility of hydraulic fluid, the actual steering angle often differs from the operator's expected steering angle during steering control, requiring the operator to make corrections. Furthermore, with prolonged operation, the hydraulic fluid inevitably becomes contaminated, leading to problems such as heavy steering, slow steering, and steering delay. This significantly reduces the comfort of steering operations, lowers work efficiency, and poses certain safety hazards. Summary of the Invention

[0003] In order to overcome the above-mentioned shortcomings of the prior art, the present invention provides a front wheel steering device and control method for a grader, so as to optimize the front wheel steering operation of the grader, improve the predictability, comfort and safety of the front wheel steering, improve work efficiency and reduce safety hazards.

[0004] The technical solution adopted by this invention to solve its technical problem is:

[0005] A front wheel steering device for a grader includes a front wheel structure body. The front wheel structure body is driven and steered by an electric cylinder. The electric cylinder is driven by a power control system, which includes a handle, a steering wheel, a first controller, a second controller, an engine, a generator, a rectifier, an inverter, and a vehicle speed sensor. The generator input is rigidly connected to the engine, and the generator output is connected to the rectifier input via a cable. The rectifier output is connected to the inverter input via a cable, and the inverter output is connected to the electric cylinder motor via a cable. The inverter control terminal is connected to the second controller output via a cable. The output terminals of the handle and steering wheel are connected to the input terminal of the first controller via a wiring harness. The output terminal of the first controller is connected to the input terminal of the second controller via a wiring harness. The first controller is communicatively connected to the handle, steering wheel, vehicle speed sensor, and electric cylinder displacement sensor. The first controller processes the received output signals from the handle or steering wheel, vehicle speed sensor, and electric cylinder displacement sensor and sends them to the second controller. The second controller controls the inverter to output the corresponding current according to the signal output by the first controller. The inverter outputs current to the electric cylinder. After receiving the current signal, the electric cylinder realizes the drive steering of the main body of the front wheel structure.

[0006] Preferably, the main body of the front wheel structure includes a front axle, an electric cylinder, a steering tie rod, a left steering ball joint, a right steering ball joint, a left steering joint, a right steering joint, a left steering shaft, a right steering shaft, a left front wheel, and a right front wheel. The electric cylinder includes an electric cylinder screw, an electric cylinder displacement sensor, an electric cylinder motor, and an electric cylinder reduction device. The two ends of the electric cylinder screw are fixed to the front axle. The electric cylinder reduction device is ball-jointed to the middle of the steering tie rod. The two ends of the steering tie rod are connected to the front axle through the left and right steering ball joints, respectively. The left front wheel is mounted on the left side of the front axle through the left steering joint, and the right front wheel is mounted on the right side of the front axle through the right steering joint. The left steering joint is connected to the front axle through the left steering shaft, and the right steering joint is connected to the front axle through the right steering shaft. The electric cylinder reduction device is mounted on the electric screw and is driven by the electric cylinder motor to move along the motor screw. The electric cylinder reduction device moves the steering tie rod, which in turn moves the steering joint. The steering joint moves the two front wheels to the left or right around the steering shaft.

[0007] Preferably, the first controller is connected to the electric cylinder displacement sensor and the vehicle speed sensor via a wiring harness.

[0008] Preferably, the generator is an AC generator.

[0009] Preferably, the electric motor is a diesel or gasoline engine with an independent steering system and is controlled by the grader's automatic control system.

[0010] The present invention also provides a control method for the above-mentioned front wheel steering device of a grader, specifically including:

[0011] (1) When the handle is turned, the steering speed of the front wheel is inversely proportional to the vehicle speed. The rotation angle of the front wheel is the same as the rotation angle of the handle. That is, the front wheel follows the handle to rotate at the same angle. When the handle is released during the turning process, the handle does not automatically return to the center position. The front wheel maintains the steering angle corresponding to the handle.

[0012] (2) When the steering wheel is turned, if the vehicle speed is less than or equal to 5 km / h, the steering wheel is released during the turning process and the steering wheel does not automatically return to the center position. The front wheels maintain the turning angle corresponding to the steering wheel. If the vehicle speed is greater than 5 km / h, the steering wheel is released during the turning process and the steering wheel automatically returns to the center position. The front wheels follow the steering wheel back to the center position. The front wheel rotation angle corresponds to the steering wheel rotation angle. That is, when the steering wheel is turned clockwise three times, the front wheels turn from the leftmost end to the rightmost end.

[0013] (3) When the first controller receives signals from both the handle and the steering wheel, it automatically blocks the handle signal and prioritizes the steering wheel signal, that is, the steering wheel steering action takes precedence over the handle steering action.

[0014] Preferably, the center position is the position where the steering wheel or wheels are straightened.

[0015] Beneficial effects:

[0016] Compared with the prior art, the advantages of the grader front wheel steering device and control method of the present invention are as follows:

[0017] (1) The present invention uses an electric cylinder as the steering drive power, which can avoid problems such as hydraulic oil leakage when the hydraulic cylinder is driven.

[0018] (2) When the steering drive of the present invention is driven by the vehicle speed, the steering speed can be determined according to the vehicle speed, thereby improving the steering safety.

[0019] (3) The present invention can better ensure the correspondence between the wheel steering angle and the steering of the handle or steering wheel, and can improve the predictability and comfort of the front wheel steering.

[0020] (4) The present invention uses the inverter output current signal to control the electric cylinder through the controller, which can better achieve precise control of the steering angle, improve the predictability, comfort and safety of wheel steering, improve work efficiency and reduce safety hazards. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Figure 1 This is a schematic diagram of the main structure of the front wheel steering device of a grader according to an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the electric steering cylinder for the front wheel of a grader according to an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the front wheel steering power control system of a grader according to an embodiment of the present invention;

[0025] In the picture:

[0026] 1-Front axle body; 2-Electric cylinder; 2-1-Electric cylinder lead screw; 2-2-Electric cylinder displacement sensor; 2-3-Electric cylinder motor; 2-4-Electric cylinder reduction gear; 3-Left steering shaft; 4-Left front wheel; 5-Left steering joint; 6-Left steering ball joint; 7-Steering tie rod; 8-Right steering ball joint; 9-Right steering joint; 10-Right front wheel; 11-Right steering shaft; 12-Handle handle; 13-Steering wheel; 14-Engine; 15-Generator; 16-Rectifier; 17-Inverter; 18-Second controller; 19-First controller; 20-Vehicle speed sensor. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0028] like Figure 1-3 As shown, this embodiment of the invention provides a front wheel steering device and control method for a grader.

[0029] A front wheel steering device for a grader includes a front wheel structure body. The front wheel structure body is driven and steered by an electric cylinder, which is driven by a power control system. The front wheel structure body includes a front axle 1, an electric cylinder 2, a steering tie rod 7, a left steering ball joint 6, a right steering ball joint 8, a left steering joint 5, a right steering joint 9, a left steering shaft 3, a right steering shaft 11, a left front wheel 4, and a right front wheel 10. The electric cylinder 2 includes an electric cylinder screw 2-1, an electric cylinder reduction device 2-4, an electric cylinder motor 2-3, and an electric cylinder displacement sensor 2-2. The two ends of the electric cylinder screw 2-1 are fixed to the front axle 1. The electric cylinder reduction device 2-4 is connected to the middle ball joint of the steering tie rod 7. The two ends of the steering tie rod 7 are respectively connected via the left steering ball joint 6 and the right steering ball joint 8. The right steering ball joint 8 is connected to the front axle body 1. The left front wheel 4 is mounted on the left side of the front axle body 1 via the left steering joint 5. The right front wheel 10 is mounted on the right side of the front axle body 1 via the right steering joint 9. The left steering joint 5 is connected to the front axle body 1 via the left steering shaft 3. The right steering joint 9 is connected to the front axle body 1 via the right steering shaft 11. After receiving current, the electric cylinder motor 2-3 starts to rotate, driving the electric cylinder reduction device 2-4 to move along the motor lead screw 2-1. The electric cylinder reduction device 2-4 moves the steering tie rod 7. The steering tie rod 7 drives the left steering joint 5 and the right steering joint 9 to move. The left steering joint 5 drives the left front wheel 4 to move left or right around the left steering shaft 3. The right steering joint 9 drives the right front wheel 10 to move left or right around the right steering shaft 11.

[0030] The power control system includes a handle 12, a steering wheel 13, a first controller 19, a second controller 18, an engine 14, a generator 15, a rectifier 16, an inverter 17, and a vehicle speed sensor 20. The input terminal of the generator 15 is rigidly connected to the engine 14. The output terminal of the generator 15 is connected to the input terminal of the rectifier 16 via a cable. The output terminal of the rectifier 16 is connected to the input terminal of the inverter 17 via a cable. The output terminal of the inverter 17 is connected to the electric cylinder motor 2-3 via a cable. The control terminal of the inverter 17 is connected to the output terminal of the second controller 18 via a wiring harness. The output terminals of the handle 12 and the steering wheel 13 are connected to the input terminals of the first controller 19 via wiring harnesses. The output terminal of the first controller 19 is connected to the input terminal of the second controller 18 via wiring harnesses. After receiving the output signal from the handle 12 or the steering wheel 13, the first controller 19 sends a corresponding signal to the second controller 18. The second controller 18 then sends a corresponding signal to the inverter 17. The inverter 17 outputs a corresponding current to the electric cylinder 2. After receiving the current signal, the electric cylinder 2 realizes the steering movement.

[0031] In order to achieve precise positioning control of front wheel steering, the first controller 19 is also connected to the electric cylinder displacement sensor 2-2 and the vehicle speed sensor 20 through wiring harnesses, and the motion signal and vehicle speed signal of the electric cylinder 2 are fed back to the first controller 19 in real time.

[0032] The generator is an AC generator. The electric motor is a diesel or gasoline engine with an independent steering system and is controlled by the grader's automatic control system.

[0033] The components mentioned in this embodiment, such as the front axle 1, electric cylinder 2, steering tie rod 7, left steering ball joint 6, right steering ball joint 8, left steering joint 5, right steering joint 9, left steering shaft 3, right steering shaft 11, left front wheel 4, right front wheel 10, electric cylinder lead screw 2-1, electric cylinder reduction device 2-4, electric cylinder motor 2-3 and electric cylinder displacement sensor 2-2, handle 12, steering wheel 13, first controller 19, second controller 18, engine 14, generator 15, rectifier 16, inverter 17 and vehicle speed sensor 20, are all existing products or structures well known to those skilled in the art, and will not be described in detail here. The connection or control methods between them not described in this embodiment also adopt existing connection or control methods well known to those skilled in the art.

[0034] The working principle of the front wheel steering control method for the grader in this embodiment is as follows:

[0035] The input terminal of generator 15 is rigidly connected to engine 14 to convert mechanical energy into electrical energy. The output terminal of generator 15 is connected to the input terminal of rectifier 16 via a cable. The output terminal of rectifier 16 is connected to the input terminal of inverter 17 via a cable. The output terminal of inverter 17 is connected to electric cylinder motor 2-3 via a cable. When engine 15 is running, generator 15 outputs AC power. This AC power is rectified and regulated by rectifier 16 into stable DC power. The AC power then enters inverter 17 and is converted back into stable AC power. When this AC power is applied to electric cylinder motor 2-3, electric cylinder motor 2-3 rotates, thereby driving electric cylinder reduction device 2-4 to move linearly along reducer screw 2-1. Since electric cylinder reduction device 2-4 is connected to steering tie rod 7 via a ball joint, and steering tie rod 7 is connected to steering joint via a steering ball joint, and steering joint is connected to the front axle via a shaft, with the two front wheels mounted on the two steering joints, when electric cylinder reduction device 2-4 moves linearly along reducer screw 2-1, both front wheels simultaneously turn left or right. During this process, second controller 18 controls inverter 17 by outputting different signals to adjust the current flow and magnitude, thereby controlling the front wheel steering speed.

[0036] After receiving signals from the handle 12, vehicle speed sensor 20, and electric cylinder displacement sensor 2-2, the first controller 19 processes the three signals. The specific processing method is described in the control method. The corresponding signal is then sent to the second controller 18, which in turn sends the corresponding signal to the inverter 17. The inverter 17 outputs the corresponding current to the electric cylinder 2. After receiving the current signal, the electric cylinder 2 realizes the front wheel steering movement.

[0037] After receiving signals from the steering wheel 13, vehicle speed sensor 20, and electric cylinder displacement sensor 2-2, the first controller 19 processes the three signals. The specific processing method is described in the control method. The corresponding signal is then sent to the second controller 18, which in turn sends the corresponding signal to the inverter 17. The inverter 17 outputs the corresponding current to the electric cylinder 2. After receiving the current signal, the electric cylinder 2 realizes the front wheel steering movement.

[0038] The specific control method is as follows:

[0039] (1) In order to improve the comfort of using the handle 12 to control the front wheel steering, the front wheel rotation angle is consistent with the handle 12 rotation angle, that is, the front wheel follows the handle 12 to rotate at the same angle. When the handle 12 is released during the steering process, the handle 12 does not automatically return to the center position. The front wheel maintains the steering angle corresponding to the handle 12. In order to ensure the safety of using the handle 12 to control the front wheel steering, when the handle is turned to the 12th direction, the steering speed of the front wheel 12 is inversely proportional to the vehicle speed. That is, under the same conditions, when the handle 12 is turned to the same angle, the larger the feedback signal of the vehicle speed sensor 20 (the faster the vehicle speed), the smaller the output signal of the first controller 19, the smaller the output current of the second controller 18, and the slower the steering speed, and vice versa.

[0040] (2) In order to improve the comfort of using the steering wheel 13 to control the front wheel steering, the front wheel rotation angle corresponds one-to-one with the steering wheel 13 rotation angle. When the steering wheel 13 is turned three times, the front wheel turns from the leftmost end to the rightmost end. In order to ensure the comfort of using the steering wheel 13 to control the front wheel steering, when the steering wheel 13 is turning, the vehicle speed is less than or equal to 5km / h. When the steering wheel 13 is released during the turning process, the steering wheel 13 does not automatically return to the center position. The front wheel maintains the steering angle corresponding to the steering wheel 13. When the vehicle speed is greater than 5km / h, when the steering wheel 13 is released during the turning process, the steering wheel 13 automatically returns to the center position, and the front wheel also returns to the center position.

[0041] (3) In order to prevent operator misoperation and ensure the safety of steering the front wheel, when the first controller 19 receives signals from both the handle 12 and the steering wheel 13, it automatically blocks the handle 12 signal and prioritizes the steering wheel 13 signal, that is, the steering wheel 13 steering action takes precedence over the handle 12 steering action.

[0042] In this example, the "center position" refers to the position where the steering wheel or wheels are straightened.

[0043] In summary, this embodiment proposes a front wheel steering device and control method for a grader. By operating a handle or steering wheel in the grader's cab, an electric cylinder mounted on the front axle structure is controlled, enabling left and right steering of the front wheels. The electric cylinder is powered by a generator in the power control system. A first controller receives signals from the handle, steering wheel, vehicle speed sensor, and electric cylinder displacement sensor, processes and analyzes them, and sends corresponding signals to a second controller. The second controller then sends corresponding signals to an inverter, which outputs a corresponding current to drive the electric cylinder, thereby achieving left and right steering of the front wheels. The second controller controls the inverter by outputting different signals to adjust the current flow and magnitude, thus controlling the front wheel steering speed. During this process, if the handle is used, the front wheel rotation angle matches the handle rotation angle; if the steering wheel is used, the front wheel rotation angle corresponds one-to-one with the steering wheel rotation angle. Three full rotations of the steering wheel move the front wheels from the leftmost to the rightmost position.

[0044] This embodiment uses an electric cylinder as the steering drive power, which can avoid problems such as hydraulic oil leakage when the hydraulic cylinder is driven. In this embodiment, when the front wheel is steering, the vehicle speed is introduced as a parameter, which can determine the steering speed according to the vehicle speed, thereby improving steering safety.

[0045] This embodiment better ensures the correspondence between the wheel steering angle and the steering input via the hand lever or steering wheel, improving the anticipation and comfort of front wheel steering. By using an inverter-output current signal to control the electric cylinder through a controller, this embodiment achieves more precise control of the steering angle, further enhancing wheel steering anticipation, comfort, and safety, increasing work efficiency, and reducing safety hazards.

[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications and equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A control method for the front wheel steering device of a grader, characterized in that: The front wheel steering device of this grader includes a front wheel structure body, which is driven and steered by an electric cylinder. The electric cylinder is driven by a power control system, which includes a handle, a steering wheel, a first controller, a second controller, an engine, a generator, a rectifier, an inverter, and a vehicle speed sensor. The generator input is rigidly connected to the engine, and the generator output is connected to the rectifier input via a cable. The rectifier output is connected to the inverter input via a cable, and the inverter output is connected to the electric cylinder motor via a cable. The inverter control terminal is connected to the second controller output via a wiring harness. The handle and... The steering wheel output terminal is connected to the first controller input terminal via a wiring harness. The first controller output terminal is connected to the second controller input terminal via a wiring harness. The first controller is communicatively connected to the handle, steering wheel, vehicle speed sensor, and electric cylinder displacement sensor. The first controller processes the received handle or steering wheel output signals, vehicle speed sensor signals, and electric cylinder displacement sensor signals and sends them to the second controller. The second controller controls the inverter to output corresponding current based on the signal output by the first controller. The inverter outputs current to the electric cylinder. After receiving the current signal, the electric cylinder realizes the drive steering of the front wheel structure. The control method specifically includes: (1) When the handle is turned, the steering speed of the front wheel is inversely proportional to the vehicle speed. The rotation angle of the front wheel is the same as the rotation angle of the handle. That is, the front wheel follows the handle to rotate at the same angle. When the handle is released during the turning process, the handle does not automatically return to the center position. The front wheel maintains the steering angle corresponding to the handle. (2) When the steering wheel is turned, if the vehicle speed is less than or equal to 5 km / h, the steering wheel is released during the turning process and the steering wheel does not automatically return to the center position. The front wheels maintain the turning angle corresponding to the steering wheel. If the vehicle speed is greater than 5 km / h, the steering wheel is released during the turning process and the steering wheel automatically returns to the center position. The front wheels follow the steering wheel back to the center position. The front wheel rotation angle corresponds to the steering wheel rotation angle. That is, when the steering wheel is turned clockwise three times, the front wheels turn from the leftmost end to the rightmost end. (3) When the first controller receives signals from both the handle and the steering wheel, it automatically blocks the handle signal and prioritizes the steering wheel signal, that is, the steering wheel steering action takes precedence over the handle steering action.

2. The control method for the front wheel steering device of a grader according to claim 1, characterized in that: The main body of the front wheel structure includes a front axle, an electric cylinder, a steering tie rod, a left steering ball joint, a right steering ball joint, a left steering joint, a right steering joint, a left steering shaft, a right steering shaft, a left front wheel, and a right front wheel. The electric cylinder includes an electric cylinder screw, an electric cylinder displacement sensor, an electric cylinder motor, and an electric cylinder reduction device. The two ends of the electric cylinder screw are fixed to the front axle. The electric cylinder reduction device is ball-jointed to the middle of the steering tie rod. The two ends of the steering tie rod are connected to the front axle through the left and right steering ball joints, respectively. The left front wheel is mounted on the left side of the front axle through the left steering joint, and the right front wheel is mounted on the right side of the front axle through the right steering joint. The left steering joint is connected to the front axle through the left steering shaft, and the right steering joint is connected to the front axle through the right steering shaft. The electric cylinder reduction device is mounted on the electric screw and is driven by the electric cylinder motor to move along the motor screw. The electric cylinder reduction device moves the steering tie rod, which in turn moves the steering joint. The steering joint moves the two front wheels to the left or right around the steering shaft.

3. The control method for the front wheel steering device of a grader according to claim 1, characterized in that: The first controller is connected to the electric cylinder displacement sensor and the vehicle speed sensor via a wiring harness.

4. The control method for the front wheel steering device of a grader according to claim 1, characterized in that: The generator is an AC generator.

5. The control method for the front wheel steering device of a grader according to claim 1, characterized in that: The "center position" refers to the position where the steering wheel or wheels are straightened.

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