Tractor steering system

Abstract

The utility model discloses a tractor steering system which comprises a frame, wheels, a first rocker, a second rocker, a connecting rod, an engine, a hydraulic pump, a three-position four-way proportional reversing valve, a hydraulic cylinder, a PLC (programmable logic controller), a steering wheel and an encoder. A control signal is output after a signal input by the encoder is calculated by the PLC, the control signal is converted into an analog signal through the D / A converter, and the analog signal is amplified by the power amplifier and then drives a valve element of the three-position four-way proportional reversing valve to move. The displacement sensor is used for detecting the expansion and contraction amount of the hydraulic cylinder, and a displacement signal is converted into a digital signal through the A / D converter and input into the PLC. The tractor is small in turning radius and convenient to operate.

Description

TECHNICAL FIELD

[0001] The utility model relates to steering technical field especially relates to a tractor steering system. BACKGROUND

[0002] As an important transport tool, the tractor is widely used in the field of goods transportation. Generally, the tractor is divided into two kinds of semi-trailer tractor and full trailer tractor.

[0003] The existing tractor steering adopts the front wheel steering mode, and realizes steering through the friction force between the front wheel and the ground. When the driver rotates the steering wheel, the steering mechanism drives the front wheel to deflect, so as to change the driving direction of the vehicle. By adopting the front wheel steering mode, the turning radius is large, and the operation is inconvenient. SUMMARY

[0004] In order to solve the above problems of the prior art, the utility model provides a tractor steering system.

[0005] The main technical scheme adopted by the utility model is:

[0006] A tractor steering system, characterized in that it comprises a frame, a wheel, a first rocker, a second rocker, a connecting rod, one end of the first rocker is hinged to the frame, the other end of the first rocker is hinged to the connecting rod, one end of the second rocker is hinged to the connecting rod, the other end of the second rocker is hinged to the frame, and the first rocker is fixed on the wheel; further comprising an engine, a hydraulic pump, a three-position four-way proportional directional valve, and a hydraulic cylinder, the output shaft of the engine is connected with the input shaft of the hydraulic pump, the hydraulic pump is connected with the three-position four-way proportional directional valve, the three-position four-way proportional directional valve is connected with the hydraulic cylinder, one end of the hydraulic cylinder is hinged to the frame, and the other end of the hydraulic cylinder is hinged to the second rocker; further comprising a PLC controller, a steering wheel, and an encoder, the steering wheel is connected with the encoder, the encoder is connected with the PLC controller, the control signal output after the signal input by the encoder is calculated by the PLC controller, the control signal is converted into an analog signal by a D / A converter, and the analog signal drives the spool of the three-position four-way proportional directional valve to move after being amplified by a power amplifier; a displacement sensor is used for detecting the extension amount of the hydraulic cylinder, and the displacement signal is converted into a digital signal by an A / D converter and input to the PLC controller.

[0007] Preferably, the inlet of the hydraulic pump is provided with a filter, and the outlet of the hydraulic pump is provided with an overflow valve.

[0008] Preferably, the utility model further comprises a camera and a touch screen for collecting image information of the wheel, and the camera and the touch screen are respectively connected with the PLC controller.

[0009] As preferred, the outlet of the hydraulic pump is provided with a pressure sensor, the hydraulic cylinder is provided with a hydraulic oil level sensor, the pressure sensor and the hydraulic oil level sensor are connected with the PLC controller respectively, and the PLC controller displays the hydraulic oil level and the outlet pressure of the hydraulic pump on the touch screen through a preset program.

[0010] As preferred, the touch screen is a 7-inch touch screen with a model of 6071IK.

[0011] As preferred, the hydraulic pump is a swash plate type axial piston pump, and the hydraulic cylinder is a single-plunger hydraulic cylinder.

[0012] As preferred, the PLC controller is a Siemens S7-1200 series PLC.

[0013] As preferred, the displacement sensor is a magnetostrictive displacement sensor, and the encoder is an incremental rotary encoder.

[0014] The utility model discloses a have as follows beneficial effect: adopt this technical scheme, first rocker, second rocker, connecting rod, wheel constitute plane four -link mechanism, and the rotation of wheel is controlled through the telescopic control of hydraulic cylinder;The opening size and direction of three -way proportional reversing valve are controlled by PLC controller, thereby the telescopic amount of hydraulic cylinder is controlled;The displacement sensor carries out real -time feedback to the position of hydraulic cylinder, constitutes closed -loop control, realizes the accurate control to the wheel rotation angle. Vehicle turning radius is smaller, and the operation is convenient. BRIEF DESCRIPTION OF DRAWINGS

[0015] Fig. 1 It is steering mechanism structural schematic diagram;

[0016] Fig. 2 It is steering hydraulic system schematic diagram;

[0017] Fig. 3 It is control flow chart.

[0018] In the drawing, 1 wheel, 2 first rocker, 3 second rocker, 4 connecting rod, 5 car frame, 6 hydraulic pump, 7 three -way proportional reversing valve, 8 hydraulic cylinder, 9 filter, 10 overflow valve, 11 power amplifier, 12 oil cylinder, 13 encoder. DETAILED DESCRIPTION

[0019] In order to better explain the utility model, in order to facilitate understanding, the utility model is described in detail below in combination with the drawings through specific embodiments.

[0020] Example one

[0021] The following is combined with the Figs. 1-3 The utility model is further explained as follows:

[0022] A tractor steering system, comprising a frame 5, a wheel 1, a first rocker 2, a second rocker 3, a connecting rod 4, one end of the first rocker 2 being hinged to the frame 5, the other end of the first rocker 2 being hinged to the connecting rod 4, one end of the second rocker 3 being hinged to the connecting rod 4, the other end of the second rocker 3 being hinged to the frame 5, the first rocker 2 being fixed on the wheel 1; further comprising an engine, a hydraulic pump 6, a three-position four-way proportional directional valve 7, a hydraulic cylinder 8, the output shaft of the engine being connected to the input shaft of the hydraulic pump 6, the hydraulic pump 6 being connected to the three-position four-way proportional directional valve 7, the three-position four-way proportional directional valve 7 being connected to the hydraulic cylinder 8, one end of the hydraulic cylinder 8 being hinged to the frame 5, the other end of the hydraulic cylinder 8 being hinged to the second rocker 3; further comprising a PLC controller, a steering wheel being connected to an encoder 13, the encoder 13 being connected to the PLC controller, the control signal output by the encoder 13 after calculation by the PLC controller, the control signal being converted into an analog signal by a D / A converter, the analog signal being amplified by a power amplifier 11 to drive the spool of the three-position four-way proportional directional valve 7 to move; a displacement sensor being used to detect the extension and retraction amount of the hydraulic cylinder 8, the displacement signal being converted into a digital signal by an A / D converter and input to the PLC controller.

[0023] In this embodiment, the hydraulic pump 6 is a swash plate type axial piston pump, the hydraulic cylinder 8 is a single piston hydraulic cylinder 8, the controller is a Siemens S7-1200 series PLC, the displacement sensor is a magnetostrictive displacement sensor, the encoder 13 is an incremental rotary encoder 13, and the control algorithm is a PID algorithm.

[0024] By adopting this technical scheme, the first rocker 2, the second rocker 3, the connecting rod 4 and the wheel 1 form a planar four-bar mechanism, the rotation of the wheel 1 is controlled through the extension and retraction of the hydraulic cylinder 8; the PLC controller controls the opening size and direction of the three-position four-way proportional directional valve 7, thereby controlling the extension and retraction amount of the hydraulic cylinder 8; the displacement sensor performs real-time feedback on the position of the hydraulic cylinder 8, a closed-loop control is formed, and accurate control over the rotation angle of the wheel 1 is realized. The turning radius of the vehicle is small, and the operation is convenient.

[0025] Embodiment two

[0026] In this embodiment, a filter 9 is arranged at the inlet of the hydraulic pump 6, hydraulic oil enters the hydraulic pump 6 from the oil cylinder 12 through the filter 9, and an overflow valve 10 is arranged at the outlet of the hydraulic pump 6.

[0027] Embodiment three

[0028] In this embodiment, the tractor steering system further comprises a camera for collecting image information of the wheel 1 and a touch screen, the camera and the touch screen are respectively connected to the PLC controller; the image information of the wheel 1 is viewed through the touch screen. The touch screen adopts a 7-inch touch screen, and the model is 6071IK.

[0029] Embodiment four

[0030] In this embodiment, the outlet of the hydraulic pump 6 is provided with a pressure sensor, and the hydraulic oil cylinder 12 is provided with a hydraulic oil level sensor; the pressure sensor and the hydraulic oil level sensor are connected with a PLC controller respectively; the PLC controller displays the hydraulic oil level and the outlet pressure of the hydraulic pump 6 on a touch screen through a preset program.

[0031] The above-mentioned embodiments of the utility model do not constitute the limitation to the protection scope of the utility model. Any modification, equivalent replacement and improvement made within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. A tractor steering system, characterized in that: The application relates to a vehicle frame, wheels, a first rocker, a second rocker, a connecting rod, one end of the first rocker is hinged to the vehicle frame, the other end of the first rocker is hinged to the connecting rod, one end of the second rocker is hinged to the connecting rod, the other end of the second rocker is hinged to the vehicle frame, and the first rocker is fixed on the wheels; the application further comprises an engine, a hydraulic pump, a three-position four-way proportional reversing valve and a hydraulic cylinder, the output shaft of the engine is connected with the input shaft of the hydraulic pump, the hydraulic pump is connected with the three-position four-way proportional reversing valve, the three-position four-way proportional reversing valve is connected with the hydraulic cylinder, one end of the hydraulic cylinder is hinged to the vehicle frame, and the other end of the hydraulic cylinder is hinged to the second rocker; the application further comprises a PLC controller, a steering wheel and an encoder, the steering wheel is connected with the encoder, the encoder is connected with the PLC controller, the control signal output by the encoder after calculation by the PLC controller, the control signal is converted into an analog signal through a D / A converter, the analog signal is amplified through a power amplifier to drive the valve core of the three-position four-way proportional reversing valve to move, and a displacement sensor is used for detecting the extension and retraction amount of the hydraulic cylinder, and the displacement signal is converted into a digital signal through an A / D converter and input into the PLC controller.

2. A tow vehicle steering system as claimed in claim 1, wherein, The inlet of the hydraulic pump is provided with a filter, and the outlet of the hydraulic pump is provided with an overflow valve.

3. A tow vehicle steering system as claimed in claim 1, wherein, The application further comprises a camera and a touch screen for collecting image information of the wheels, and the camera and the touch screen are connected with the PLC controller respectively.

4. A tractor steering system according to claim 3, wherein, The outlet of the hydraulic pump is provided with a pressure sensor, and the hydraulic cylinder is provided with a hydraulic oil level sensor, the pressure sensor and the hydraulic oil level sensor are connected with the PLC controller respectively, and the PLC controller displays the hydraulic oil level and the outlet pressure of the hydraulic pump on the touch screen through a preset program.

5. The system of claim 3, wherein, The touch screen is a 7-inch touch screen with a model number of 6071IK.

6. A tow vehicle steering system as claimed in claim 1, wherein, The hydraulic pump is a swash plate type axial piston pump, and the hydraulic cylinder is a single-plunger hydraulic cylinder.

7. A tow vehicle steering system as claimed in claim 1, wherein, The PLC controller is a Siemens S7-1200 series PLC.

8. A tow vehicle steering system as claimed in claim 1, wherein, The displacement sensor is a magnetostrictive displacement sensor, and the encoder is an incremental rotary encoder.

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