Stepless speed change control mechanism of tractor

Abstract

The utility model discloses a tractor stepless speed change control mechanism which comprises a power input shaft used for receiving power output of an engine; the volume adjustable hydraulic pump is connected with the power input shaft, converts mechanical energy of the power input shaft into hydraulic energy and can change the flow of output hydraulic oil by adjusting the displacement of the volume adjustable hydraulic pump; the hydraulic motor is connected with the volume adjustable hydraulic pump through a hydraulic pipeline, receives the hydraulic energy output by the volume adjustable hydraulic pump and converts the hydraulic energy into mechanical energy to output power, and an output shaft of the hydraulic motor is connected with the rear wheel walking component; the control mechanism is connected with the variable hydraulic pump and used for adjusting the displacement of the variable hydraulic pump according to an external control instruction, and then stepless adjustment of the output rotating speed and torque of the hydraulic motor is achieved so as to meet the requirements of different walking working conditions. The stepless speed change control mechanism of the tractor can realize stepless speed change through hydraulic transmission, and improves the adaptability and operation flexibility of the tractor.

Description

TECHNICAL FIELD

[0001] The utility model relates to agricultural machinery technical field, concretely is tractor stepless speed change control mechanism. BACKGROUND

[0002] The existing tractor walking is all through mechanical structure control control gear shifting, namely through gear set transmission, and frequent gear shifting is easy to damage the gear, and further causes the transmission case to be prone to failure, influences work efficiency, and in different working conditions, mechanical gear shifting makes the steering not flexible, cannot keep stable walking. SUMMARY

[0003] The utility model solves the technical problem to overcome the existing defects, provide a tractor stepless speed change control mechanism, can realize stepless speed change through hydraulic transmission, improve the adaptability and operation flexibility of tractor, can effectively solve the problem in the background art.

[0004] To realize above-mentioned purpose, the utility model provides the following technical scheme: a tractor stepless speed change control mechanism, including:

[0005] Power input shaft for receiving the power output of engine;

[0006] Variable hydraulic pump, connecting the power input shaft, the mechanical energy of power input shaft is converted into hydraulic energy, and the hydraulic oil flow of output can be changed by adjusting the displacement of itself;

[0007] Hydraulic motor, through hydraulic pipeline with variable hydraulic pump is connected, receives the hydraulic energy of variable hydraulic pump output, converts hydraulic energy into mechanical energy output power, the output shaft of hydraulic motor is connected with rear wheel walking part;

[0008] Control mechanism, with variable hydraulic pump is connected, for adjusting the displacement of variable hydraulic pump according to external control instruction, further realizes stepless regulation to the output speed and torque of hydraulic motor, to meet the different walking working condition demand;

[0009] Oil tank, through hydraulic pipeline with variable hydraulic pump and hydraulic motor is connected, for storing hydraulic oil, and provides oil circulation passway for entire hydraulic system.

[0010] As a preferred technical scheme of the utility model, the variable hydraulic pump is swash plate type variable plunger pump.

[0011] As a preferred technical scheme of the utility model, the hydraulic motor is fixed displacement hydraulic motor, and the required hydraulic oil volume of each rotation is fixed, and the output torque and speed are corresponding with the input hydraulic oil flow and pressure.

[0012] As a preferred technical scheme of the utility model, the control mechanism comprises a rotating speed sensor and a controller, the rotating speed sensor is arranged on the rear wheel and is used for detecting the rotating speed of the rear wheel, and the output end of the rotating speed sensor is electrically connected with the input end of the controller.

[0013] As a preferred technical scheme of the utility model, a speed reducer is arranged between the hydraulic motor and the rear wheel of the tractor.

[0014] As a preferred technical scheme of the utility model, filters are arranged on the hydraulic pipelines between the oil tank and the variable hydraulic pump and between the oil tank and the hydraulic motor.

[0015] As a preferred technical scheme of the utility model, a safety protection assembly is further arranged, the safety protection assembly comprises an overflow valve and a pressure cut-off valve, the overflow valve is arranged on the hydraulic pipeline between the hydraulic motor and the oil tank, and the pressure cut-off valve is arranged on the control oil circuit of the variable hydraulic pump.

[0016] Compared with the prior art, the utility model has the advantages that the stepless speed change control mechanism of the tractor is reasonable in design and ingenious in conception, the mechanical energy of power input is converted into hydraulic energy through the variable hydraulic pump, then the hydraulic energy is converted into mechanical energy to control the tractor to walk through the rotation of the hydraulic motor controlled by the hydraulic oil, the walking speed is controlled through the displacement of the variable hydraulic pump, stepless speed change is realized, the steering flexibility is improved, the tractor keeps uniform speed steering under different working conditions, the walking stability is improved, meanwhile, the hydraulic transmission replaces the mechanical transmission, the energy loss can be reduced, the failure rate is reduced, and the working efficiency is greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] Fig. 1 It is a structural schematic view of the utility model;

[0018] Fig. 2 It is a hydraulic control schematic view;

[0019] Fig. 3 It is a hydraulic protection schematic view.

[0020] In the drawing: 1 power input shaft, 2 variable hydraulic pump, 3 hydraulic motor, 4 rear wheel walking part, 5 rotating speed sensor, 6 oil tank, 7 filter, 8 overflow valve, 9 pressure cut-off valve. DETAILED DESCRIPTION

[0021] The technical scheme in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Apparently, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the utility model.

[0022] Referring to Figs. 1-3 The utility model provides a technical scheme: a tractor stepless speed change control mechanism, including power input shaft 1, variable displacement hydraulic pump 2, hydraulic motor 3, control mechanism and oil tank 6,

[0023] The one end of power input shaft 1 is connected with the output end of engine, and the other end of power input shaft 1 is connected with variable displacement hydraulic pump 2, and the mechanical energy of power input shaft 1 is converted into hydraulic energy, hydraulic motor 3 is connected with variable displacement hydraulic pump 2 through hydraulic pipeline, receives the hydraulic energy output by variable displacement hydraulic pump 2, converts the hydraulic energy into mechanical energy and outputs power, the output shaft of hydraulic motor 3 is connected with rear wheel walking part 4, control mechanism is connected with variable displacement hydraulic pump 2, is used to adjust the displacement of variable displacement hydraulic pump 2 according to external control instruction, and then realizes stepless adjustment to the output rotating speed and torque of hydraulic motor 3, to satisfy different walking working condition demand, is especially suitable for the walking demand of tractor below 120 horsepower, and oil tank 6 is connected with variable displacement hydraulic pump 2 and hydraulic motor 3 through hydraulic pipeline, is used to store hydraulic oil and provide oil circulation passageway for whole hydraulic system.

[0024] In order to facilitate the accurate control of hydraulic oil flow, variable displacement hydraulic pump 2 is a swash plate type variable displacement plunger pump, and the displacement is adjusted by changing the angle of swash plate, and the change of swash plate angle is realized by hydraulic control by control mechanism.

[0025] In order to facilitate the accurate control of the output torque and rotating speed of hydraulic motor 3, hydraulic motor 3 is a fixed displacement hydraulic motor, the required hydraulic oil volume per rotation is fixed, and the output torque and rotating speed are corresponding to the input hydraulic oil flow and pressure.

[0026] Further, in order to facilitate flexible control of steering speed, the control mechanism includes a speed sensor 5 and a controller, the speed sensor 5 is arranged on the rear wheel for detecting the rotating speed of the rear wheel, and the output end of the speed sensor 5 is electrically connected with the input end of the controller, and the existing walking speed is fed back to the controller, and the speed is controlled according to the input steering, reverse and other instructions, to ensure the stability of walking.

[0027] In order to meet the power demand of tractor walking, a speed reducer is arranged between hydraulic motor 3 and the rear wheel of tractor, and the rotating speed output by hydraulic motor 3 is reduced and the torque is increased through the speed reducer.

[0028] In order to ensure the cleanliness of hydraulic system, filters 7 are arranged on the hydraulic pipelines between oil tank and variable displacement hydraulic pump 2 and between oil tank and hydraulic motor 3, for filtering impurities in hydraulic oil, to ensure the stability of hydraulic drive.

[0029] Further, in order to guarantee the safety of the walking process, a safety protection assembly is further included, the safety protection assembly includes an overflow valve 8 and a pressure cut-off valve 9, the overflow valve 8 is arranged on the hydraulic pipeline between the hydraulic motor 3 and the oil tank 6, the pressure cut-off valve 9 is arranged on the control oil circuit of the variable hydraulic pump 2, when the hydraulic system pressure exceeds the set safety pressure value, the overflow valve 8 is opened, and the excessive hydraulic oil is returned to the oil tank 6, so as to prevent the system pressure from being too high; when the system pressure abnormally rises, the pressure cut-off valve 9 acts, the control signal of the variable hydraulic pump 2 is cut off, the displacement of the variable hydraulic pump 2 is zeroed, and the whole transmission device is protected.

[0030] In use: according to the input instruction, the displacement of the variable hydraulic pump 2 is controlled, and then the output rotating speed and torque of the hydraulic motor 3 are controlled, so that the rotating speed and torque of the rear wheel walking component 4 are changed, different actions such as forward movement, backward movement and differential steering are realized, and stepless speed regulation of the tractor is realized.

[0031] The utility model can adjust the walking state of the tractor quickly and flexibly under different working conditions through the stepless speed regulation of the tractor, improve the steering flexibility of the tractor, reduce the power loss, and guarantee the safety of the whole transmission device through the safety protection assembly, and reduce the failure rate.

[0032] Although the embodiments of the utility model have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirits of the utility model, the scope of the utility model is defined by the appended claims and their equivalents.

Claims

1. A control mechanism for a tractor continuously variable transmission, characterised in that: The utility model relates to a kind of tractor hydraulic system, comprising: Power input shaft (1) for receiving the power output of engine; Variable hydraulic pump (2) connected with the power input shaft (1), the mechanical energy of the power input shaft (1) is converted into hydraulic energy, and the hydraulic oil flow of output can be changed by adjusting its displacement; Hydraulic motor (3) is connected with the variable hydraulic pump (2) by hydraulic pipeline, receives the hydraulic energy output by the variable hydraulic pump (2), and the hydraulic energy is converted into mechanical energy to output power, and the output shaft of the hydraulic motor (3) is connected with rear wheel walking parts (4); Control mechanism is connected with the variable hydraulic pump (2), for adjusting the displacement of the variable hydraulic pump (2) according to external control instruction, to realize stepless regulation to the output speed and torque of the hydraulic motor (3) in turn, to meet different walking working condition requirements; Oil tank (6) is connected with the variable hydraulic pump (2) and hydraulic motor (3) by hydraulic pipeline, for storing hydraulic oil, and providing oil circulation passage for the whole hydraulic system.

2. A control mechanism for a tractor continuously variable transmission according to claim 1, characterized in that: The variable hydraulic pump (2) is a swash plate type variable plunger pump.

3. A control mechanism for a tractor continuously variable transmission according to claim 1, characterized in that: The hydraulic motor (3) is a fixed displacement hydraulic motor, the required hydraulic oil volume per rotation is fixed, and the output torque and speed are corresponding to the input hydraulic oil flow and pressure.

4. A control mechanism for a tractor continuously variable transmission according to claim 1, characterized in that: The control mechanism includes speed sensor (5) and controller, the speed sensor (5) is arranged on rear wheel, for detecting the speed of rear wheel, and the output end of the speed sensor (5) is electrically connected with the input end of the controller.

5. A control mechanism for a tractor continuously variable transmission according to claim 1, characterized in that: The hydraulic motor (3) is provided with a speed reducer between the tractor rear wheel.

6. A control mechanism for a tractor continuously variable transmission according to claim 1, characterized in that: The oil tank and variable hydraulic pump (2) and the hydraulic pipeline between the oil tank and hydraulic motor (3) are provided with filter (7).

7. A control mechanism for a tractor continuously variable transmission according to claim 1, characterized in that: It also includes safety protection component, the safety protection component includes overflow valve (8) and pressure cut-off valve (9), the overflow valve (8) is arranged on the hydraulic pipeline between hydraulic motor (3) and oil tank (6), and the pressure cut-off valve (9) is arranged on the control oil circuit of variable hydraulic pump (2).

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