Land leveler front wheel steering device and control method

Abstract

The invention relates to a land leveler front wheel steering device and a control method, the steering device comprises a front wheel structure main body, the front wheel structure main body realizes driving steering through an electric cylinder, and the electric cylinder is driven through a power control system. The power control system comprises a handle, a steering wheel, a first controller, a second controller, an engine, a generator, a rectifier, an inverter and a vehicle speed controller, and the first controller processes received handle or steering wheel output signals, vehicle speed sensor signals and electric cylinder displacement sensor signals and then sends the signals to the second controller. The second controller controls the inverter to output corresponding current according to a signal output by the first controller, the inverter outputs the current to the electric cylinder, and after the electric cylinder receives a current signal, driving steering of the front wheel structure body is achieved, front wheel steering operation of the land leveler can be optimized, front wheel steering preachability, comfort and safety are improved, and the land leveler is suitable for large-scale popularization and application. Working efficiency is improved, and potential safety hazards are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of motor graders, and in particular to a front wheel steering device and a control method for a motor grader. Background Art

[0002] In the prior art, the front wheel steering of a grader is driven by a system consisting of a hydraulic pump, a hydraulic valve and a hydraulic cylinder. Since the internal leakage of the hydraulic components themselves and the compressibility of the oil are inevitable, the actual steering angle of the front wheel is often inconsistent with the steering angle expected by the operator during the steering control process, and the operator needs to make corrections through operation; and in the prior art, as the whole machine works for a long time, the oil is inevitably contaminated, resulting in faults such as heavy steering, slow steering and delayed steering, which in turn greatly reduces the comfort of steering operation, reduces work efficiency, and poses certain safety hazards. Summary of the invention

[0003] In order to overcome the above-mentioned deficiencies in the prior art, the present invention seeks to provide a front wheel steering device and control method for a grader 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 the present invention to solve the technical problem is:

[0005] A front wheel steering device for a grader, comprising a front wheel structural body, wherein the front wheel structural body is driven and steered by an electric cylinder, wherein the electric cylinder is driven by a power control system, wherein the power control system comprises a handle, a steering wheel, a first controller, a second controller, an engine, a generator, a rectifier, an inverter, and a vehicle speed controller, wherein an input end of the generator is rigidly connected to the engine, an output end of the generator is connected to an input end of the rectifier by a cable, an output end of the rectifier is connected to an input end of the inverter by a cable, an output end of the inverter is connected to an electric cylinder motor by a cable, and an inverter control end is connected to an output end of the second controller by a cable. The handle and steering wheel output ends are connected to the first controller input end through a wiring harness, the output end of the first controller is connected to the second controller input end through a wiring harness, the first controller is communicatively connected with the handle, steering wheel, vehicle speed sensor, and electric cylinder displacement sensor, the first controller processes the received handle or steering wheel output signal, vehicle speed sensor, and electric cylinder displacement sensor signal 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 the current to the electric cylinder, and after the electric cylinder receives the current signal, the driving steering of the front wheel structure body is realized.

[0006] Preferably, the front wheel structure body includes a front axle body, an electric cylinder, a steering rod, a left steering ball joint, a right steering ball joint, a left steering joint, a right steering joint, a left rotating shaft, a right rotating 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. Both ends of the electric cylinder screw are fixed on the front axle body. The electric cylinder reduction device is ball-jointed with the middle part of the steering rod. Both ends of the steering rod are respectively connected to the front axle body through a left steering ball joint and a right steering ball joint. The left front wheel is installed on the left side of the front axle body through the left steering joint, and the right front wheel is installed on the right side of the front axle body through the right steering joint. The left steering joint is connected to the front axle body through the left rotating shaft, and the right steering joint is connected to the front axle body through the right rotating shaft. The electric cylinder reduction device is installed on the electric screw and driven by the electric cylinder motor to move along the motor screw. The electric cylinder reduction device moves with the steering rod, and the steering rod drives the steering joint to move, and the steering joint drives the two front wheels to move left or right around the rotating 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 an independent diesel or gasoline engine for the steering system and is controlled by an automatic control system of the motor grader.

[0010] The present invention also provides a control method for the front wheel steering device of the grader, which specifically includes:

[0011] (1) When the handle is turned, the front wheel steering speed is inversely proportional to the vehicle speed, and the front wheel rotation angle remains the same as the handle rotation angle, that is, the front wheel follows the handle and rotates at the same angle. When the handle is released during the steering process, the handle does not automatically return to the middle position, and the front wheel maintains the steering angle corresponding to the handle;

[0012] (2) When the vehicle speed is less than or equal to 5 km / h, if the steering wheel is released during the steering process, the steering wheel will not automatically return to the center position, and the front wheels will maintain the steering angle corresponding to the steering wheel. When the vehicle speed is greater than 5 km / h, if the steering wheel is released during the steering process, the steering wheel will automatically return to the center position, and the front wheels will follow and return to the center position. The front wheel rotation angle corresponds to the steering wheel rotation angle, that is, the steering wheel rotates three circles clockwise, and the front wheels rotate from the leftmost end to the rightmost end;

[0013] (3) When the first controller receives signals from the handle and the steering wheel at the same time, it automatically blocks the handle signal and gives priority to the steering wheel signal, that is, the steering action of the steering wheel takes precedence over the steering action of the handle.

[0014] Preferably, the neutral position is a position state in which the steering wheel or the wheel is returned to the center.

[0015] Beneficial effects:

[0016] Compared with the prior art, the front wheel steering device and control method of a grader of the present invention have the following beneficial effects:

[0017] (1) The present invention adopts an electric cylinder as the steering drive power, which can avoid problems such as hydraulic oil leakage during hydraulic cylinder driving.

[0018] (2) During the steering drive of the present invention, the vehicle speed is introduced as a parameter, and the steering speed can be determined according to the vehicle speed, thereby better improving the steering safety.

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

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

[0021] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

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

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

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

[0025] In the figure:

[0026] 1-front axle body; 2-electric cylinder; 2-1-electric cylinder screw; 2-2-electric cylinder displacement sensor; 2-3-electric cylinder motor; 2-4-electric cylinder reduction device; 3-left shaft; 4-left front wheel; 5-left steering joint; 6-left steering ball joint; 7-steering rod; 8-right steering ball joint; 9-right steering joint; 10-right front wheel; 11-right shaft; 12-handle; 13-steering wheel; 14-engine; 15-generator; 16-rectifier; 17-inverter; 18-second controller; 19-first controller; 20-vehicle speed sensor. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

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

[0029] A front wheel steering device for a grader includes a front wheel structural body, wherein the front wheel structural body realizes driving steering through an electric cylinder, and the electric cylinder is driven by a power control system. The front wheel structural body includes a front axle body 1, an electric cylinder 2, a steering 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 rotating shaft 3, a right rotating shaft 11, a left front wheel 4 and a right front wheel 10. The electric cylinder 2 includes an electric cylinder lead screw 2-1, an electric cylinder reduction device 2-4, an electric cylinder motor 2-3 and an electric cylinder displacement sensor 2-2; both ends of the electric cylinder lead screw 2-1 are fixed on the front axle body 1, the electric cylinder reduction device 2-4 is connected to the middle ball joint of the steering rod 7, and both ends of the steering rod 7 are respectively connected through the left steering ball joint 6 and The right steering ball joint 8 is connected to the front axle body 1, the left front wheel 4 is installed on the left side of the front axle body 1 through the left steering joint 5, and the right front wheel 10 is installed on the right side of the front axle body 1 through the right steering joint 9. The left steering joint 5 is connected to the front axle body 1 through the left rotating shaft 3, and the right steering joint 9 is connected to the front axle body 1 through the right rotating shaft 11. The electric cylinder motor 2-3 starts to rotate after receiving the current, driving the electric cylinder reducer 2-4 to move along the motor screw 2-1, and the electric cylinder reducer 2-4 moves with the steering rod 7, and the steering 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 rotating shaft 3, and the right steering joint 9 drives the right front wheel 10 to move left or right around the right rotating 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 controller 20. The input end of the generator 15 is rigidly connected to the engine 14, the output end of the generator 15 is connected to the input end of the rectifier 16 through a cable, the output end of the rectifier 16 is connected to the input end of the inverter 17 through a cable, the output end of the inverter 17 is connected to the electric cylinder motor 2-3 through a cable, the control end of the inverter 17 is connected to the output end of the second controller 18 through a wiring harness, the output end of the handle 12 and the steering wheel 13 is connected to the input end of the first controller 19 through a wiring harness, and the output end of the first controller 19 is connected to the input end of the second controller 18 through a wiring harness. After receiving the output signal of the handle 12 or the steering wheel 13, the first controller 19 sends a corresponding signal to the second controller 18, and the second controller 18 sends a corresponding signal to the inverter 17, and the inverter 17 outputs a corresponding current to the electric cylinder 2. After the electric cylinder 2 receives the current signal, it realizes the steering movement.

[0031] In order to achieve precise positioning control of the 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 a wiring harness, 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 motor is an independent diesel or gasoline engine for a steering system and is controlled by an automatic control system of the grader.

[0033] The front axle body 1, electric cylinder 2, steering rod 7, left steering ball joint 6, right steering ball joint 8, left steering joint 5, right steering joint 9, left rotating shaft 3, right rotating shaft 11, left front wheel 4, right front wheel 10, electric cylinder 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 controller 20 mentioned in this embodiment are all existing products or structures well known to those skilled in the art and are not described in detail herein. The connection methods or control methods between each other not described in this embodiment also adopt the existing connection methods or control methods well known to those skilled in the art.

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

[0035] The input end of the generator 15 is rigidly connected to the engine 14 to convert mechanical energy into electrical energy. The output end of the generator 15 is connected to the input end of the rectifier 16 through a cable. The output end of the rectifier 16 is connected to the input end of the inverter 17 through a cable. The output end of the inverter 17 is connected to the electric cylinder motor 2-3 through a cable. When the engine 15 is working, the generator 15 outputs AC power, which is clipped and stabilized by the rectifier 16 and becomes stable DC power. After the AC power enters the inverter 17, it becomes stable AC power. When the AC power acts on the electric cylinder motor 2-3, the electric cylinder motor 2-3 can rotate, thereby driving the electric cylinder reduction device 2-4 to move linearly along the reducer screw 2-1; since the electric cylinder reduction device 2-4 is connected to the steering rod 7 by a ball joint, the steering rod 7 is connected to the steering joint by a steering ball joint, and the steering joint is connected to the front axle body by a rotating shaft, and the two front wheels are installed on the two steering joints, when the electric cylinder reduction device 2-4 moves linearly along the reducer screw 2-1, the two front wheels rotate to the left or right at the same time. In this process, the second controller 18 controls the inverter 17 by outputting different signals to adjust the on-off and size of the current, thereby controlling the steering speed of the front wheels.

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

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

[0038] The specific control methods are:

[0039] (1) In order to improve the comfort of using the handle 12 to control the steering of the front wheel, the rotation angle of the front wheel is consistent with the rotation angle of the handle 12, that is, the front wheel rotates at the same angle as the handle 12. When the handle 12 is released during the steering process, the handle 12 does not automatically return to the middle position, and 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 steering of the front wheel, when the handle is turned, 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 20, 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 steering of the front wheels, the rotation angle of the front wheels corresponds to the rotation angle of the steering wheel 13. When the steering wheel 13 rotates three times, the front wheels rotate from the leftmost end to the rightmost end. In order to ensure the comfort of using the steering wheel 13 to control the steering of the front wheels, when the steering wheel 13 is turned, the vehicle speed is less than or equal to 5 km / h, and the steering wheel 13 is released during the steering process, the steering wheel 13 does not automatically return to the center position, and the front wheels maintain the steering angle corresponding to the steering wheel 13. When the vehicle speed is greater than 5 km / h, and the steering wheel 13 is released during the steering process, the steering wheel 13 automatically returns to the center position, and the front wheels also return to the center position.

[0041] (3) In order to prevent the operator from operating the vehicle incorrectly and ensure the safety of steering the front wheels, when the first controller 19 receives signals from the handle 12 and the steering wheel 13 at the same time, it automatically blocks the handle 12 signal and gives priority to the steering wheel 13 signal, that is, the steering action of the steering wheel 13 takes precedence over the steering action of the handle 12.

[0042] The neutral position described in this example is the position state where the steering wheel or the wheel is returned to the center.

[0043] In summary, the front wheel steering device and control method of a grader proposed in this embodiment realizes the left and right steering of the front wheel by controlling the handle or steering wheel in the cab of the grader to control the electric cylinder installed on the main body of the front axle structure. The power of the electric cylinder comes from the generator of the power control system. The first controller receives the handle, steering wheel, vehicle speed sensor and electric cylinder displacement sensor signals, conducts comprehensive processing and analysis, and sends the corresponding signal to the second controller. The second controller then sends the corresponding signal to the inverter. The inverter outputs the corresponding current to drive the electric cylinder, thereby realizing the left and right steering of the front wheel. The second controller controls the inverter by outputting different signals to adjust the on and off and size of the current, thereby controlling the steering speed of the front wheel. In this process, if the handle is used for control, the front wheel rotation angle is consistent with the handle rotation angle. If the steering wheel is used for steering, the front wheel rotation angle corresponds to the steering wheel rotation angle one by one. When the steering wheel rotates three times, the front wheel turns from the leftmost end to the rightmost end.

[0044] This embodiment uses an electric cylinder as the steering drive power, which can avoid problems such as hydraulic oil leakage during hydraulic cylinder drive. This embodiment introduces the vehicle speed as a parameter during the front wheel steering drive, and can determine the steering speed according to the vehicle speed, thereby better improving the steering safety. This embodiment can better ensure the correspondence between the wheel steering angle and the steering manipulated by the handle or steering wheel, and can improve the predictability and comfort of the front wheel steering. This embodiment uses the inverter output current signal to control the electric cylinder through the controller, which can better achieve precise control of the steering angle, and can better improve the predictability, comfort and safety of wheel steering, improve work efficiency, and reduce safety hazards.

[0045] The above contents are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. 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 front wheel steering device for a grader, comprising a front wheel structural body, characterized in that: The front wheel structure body realizes driving steering through an electric cylinder, and the electric cylinder is driven by a power control system. The power control system 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 input end of the generator is rigidly connected to the engine, the output end of the generator is connected to the input end of the rectifier through a cable, the output end of the rectifier is connected to the input end of the inverter through a cable, the output end of the inverter is connected to the electric cylinder motor through a cable, the inverter control end is connected to the output end of the second controller through a wiring harness, the output end of the handle and the steering wheel is connected to the input end of the first controller through a wiring harness, the output end of the first controller is connected to the input end of the second controller through a wiring harness, the first controller is communicatively connected with the handle, the steering wheel, the vehicle speed sensor, and the electric cylinder displacement sensor, the first controller processes the received output signal of the handle or steering wheel, the vehicle speed sensor, and the electric cylinder displacement sensor and sends it 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 the current to the electric cylinder, and after the electric cylinder receives the current signal, the driving steering of the front wheel structure body is realized.

2. The front wheel steering device for a motor grader according to claim 1, characterized in that: The front wheel structure body includes a front axle body, an electric cylinder, a steering rod, a left steering ball joint, a right steering ball joint, a left steering joint, a right steering joint, a left rotating shaft, a right rotating 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. Both ends of the electric cylinder screw are fixed on the front axle body. The electric cylinder reduction device is ball-jointed with the middle part of the steering rod. Both ends of the steering rod are respectively connected to the front axle body through a left steering ball joint and a right steering ball joint. The left front wheel is installed on the left side of the front axle body through the left steering joint, and the right front wheel is installed on the right side of the front axle body through the right steering joint. The left steering joint is connected to the front axle body through the left rotating shaft, and the right steering joint is connected to the front axle body through the right rotating shaft. The electric cylinder reduction device is installed on the electric screw and driven by the electric cylinder motor to move along the motor screw. The electric cylinder reduction device moves with the steering rod, and the steering rod drives the steering joint to move, and the steering joint drives the two front wheels to move left or right around the rotating shaft.

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

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

5. The front wheel steering device for a motor grader according to claim 1, characterized in that: The electric motor is an independent diesel or gasoline engine for the steering system and is controlled by the automatic control system of the grader.

6. The control method of the front wheel steering device of a grader according to claim 1, characterized in that: Specifically include: (1) When the handle is turned, the front wheel steering speed is inversely proportional to the vehicle speed, and the front wheel rotation angle remains the same as the handle rotation angle, that is, the front wheel follows the handle and rotates at the same angle. When the handle is released during the steering process, the handle does not automatically return to the center position, and the front wheel maintains the steering angle corresponding to the handle; (2) When the vehicle speed is less than or equal to 5 km / h, if the steering wheel is released during the steering process, the steering wheel will not automatically return to the center position, and the front wheels will maintain the steering angle corresponding to the steering wheel. When the vehicle speed is greater than 5 km / h, if the steering wheel is released during the steering process, the steering wheel will automatically return to the center position, and the front wheels will follow and return to the center position. The front wheel rotation angle corresponds to the steering wheel rotation angle, that is, the steering wheel rotates three circles clockwise, and the front wheels rotate from the leftmost end to the rightmost end; (3) When the first controller receives signals from the handle and the steering wheel at the same time, it automatically blocks the handle signal and gives priority to the steering wheel signal, that is, the steering action of the steering wheel takes precedence over the steering action of the handle.

7. The control method of the front wheel steering device of a motor grader according to claim 6, characterized in that: The neutral position is a position state in which the steering wheel or the wheel is returned to the center.

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