Energy-saving hydraulic circuit of suspension device of electric tractor

Abstract

An energy-saving hydraulic circuit of a suspension device of an electric tractor comprises an oil tank, a filter, a hydraulic pump, a servo motor, a control rodless cavity proportional valve, a control rod cavity proportional valve, a proportional overflow valve, a hydraulic cylinder and a suspension mechanism, the hydraulic pump is driven by the servo motor, an oil inlet of the hydraulic pump is connected with the filter through a pipeline, and the filter is connected with the oil tank through a pipeline. Oil inlets of the rodless cavity control proportional valve and the rod cavity control proportional valve are connected with an oil outlet of the hydraulic pump through pipelines, an oil outlet of the valve is connected with an oil tank through a pipeline, a rodless cavity of the hydraulic cylinder is connected with a working oil port of the rodless cavity control proportional valve through a pipeline, a rod cavity of the hydraulic cylinder is connected with a working oil port of the rod cavity control proportional valve through a pipeline, and the hydraulic cylinder drives the suspension mechanism to move. The proportional overflow valve is connected with an oil inlet of the hydraulic pump through a pipeline, and an overflow port is connected with an oil tank through a pipeline. The hydraulic circuit can be used for an electro-hydraulic suspension system of the electric tractor to replace the original design, the energy efficiency of the system is improved, and energy is saved.

Description

Technical Field

[0001] The utility model relates to an electric tractor suspension system, in particular to an energy-saving hydraulic circuit of an electric tractor suspension device. Background Art

[0002] The existing electric tractors are driven by electric motors, and most of their suspension devices are electric suspension systems. Electric suspension devices have problems such as slow response speed and insufficient lifting force. The traditional suspension system is driven by a hydraulic system. The hydraulic system has the advantages of high power density ratio and fast response speed, which can overcome the defects of the electric suspension system, but has the problem of low energy efficiency, which affects the endurance of the electric tractor. In order to improve the energy efficiency of the suspension system, an energy-saving hydraulic circuit of the suspension device of an electric tractor is proposed.

[0003] In the hydraulic system of the traditional suspension system, the hydraulic pump is driven by the engine and runs at a fixed speed. The fixed speed and fixed quantity pump has a lot of throttling and overflow losses. Due to the mechanical coupling of the valve core, the control valve cannot independently control the pressure of the two chambers when driving the asymmetric cylinder, resulting in a certain internal friction of the internal pressure and a large energy loss. Utility Model Content

[0004] The utility model aims to provide an energy-saving hydraulic circuit of an electric tractor suspension device, which is used to solve the above technical problems.

[0005] The technical solution adopted by the utility model is as follows:

[0006] An energy-saving hydraulic circuit of an electric tractor suspension device comprises an oil tank 6, a filter 5, a hydraulic pump 4, a servo motor 3, a rodless cavity proportional valve 2, a rod cavity proportional valve 1, a proportional relief valve 7, a hydraulic cylinder 8 and a suspension mechanism 9.

[0007] The hydraulic pump 4 is driven by the servo motor 3 , the oil inlet of the hydraulic pump 4 is connected to the filter 5 via a pipeline, and the filter 5 is connected to the oil tank 6 via a pipeline.

[0008] The rodless chamber proportional valve 2 and the rod chamber proportional valve 1 are both three-position four-way proportional reversing valves, whose oil inlets are connected to the oil outlet of the hydraulic pump 4 via a pipeline, and the valve oil outlets are connected to the oil tank 6 via a pipeline, closing any of the two working oil ports of the valve.

[0009] The rodless chamber of the hydraulic cylinder 8 is connected to the unclosed working oil port of the rodless chamber proportional valve 2 through a pipeline, and the rod chamber is connected to the unclosed working oil port of the rod chamber proportional valve 1 through a pipeline. The hydraulic cylinder 8 drives the suspension mechanism 9 to operate.

[0010] The proportional relief valve 7 is connected to the oil inlet of the hydraulic pump 4 via a pipeline, and the overflow port is connected to the oil tank 6 via a pipeline.

[0011] One of the above technical solutions has at least the following advantages or beneficial effects:

[0012] For an energy-saving hydraulic circuit in the utility model, when the proportional valve is in the middle position, the hydraulic cylinder 8 does not work, the servo motor 3 reduces the speed or stops running, and the overflow loss is reduced. The proportional overflow valve 7 controls the oil supply pressure to always be higher than a certain load value, reducing the pressure loss. The inlet and outlet of the hydraulic cylinder 8 are respectively controlled by the proportional valve, which can independently control the pressure and flow of the two chambers of the hydraulic cylinder 8, reduce the pressure loss and flow loss, improve the energy efficiency of the hydraulic system, and improve the endurance of the electric tractor. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The figure shows a schematic diagram of an energy-saving hydraulic circuit of an electric tractor suspension device provided by the utility model;

[0014] In the figure: 1. Control rod chamber proportional valve; 2. Control rodless chamber proportional valve; 3. Servo motor; 4. Hydraulic pump; 5. Filter; 6. Oil tank; 7. Proportional relief valve; 8. Hydraulic cylinder; 9. Suspension mechanism. DETAILED DESCRIPTION

[0015] The technical solution of the utility model will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0016] The hydraulic pump 4 is driven by a servo motor 3 , and the servo motor 3 controls the rotation speed of the hydraulic pump 4 , thereby controlling the output flow of the hydraulic pump 4 .

[0017] The oil inlet of the hydraulic pump 4 is connected to the filter 5 via a pipeline, and the filter 5 is connected to the oil tank 6 via a pipeline. The filter 5 filters the hydraulic oil entering the hydraulic system to remove various impurities.

[0018] The rodless chamber proportional valve 2 and the rod chamber proportional valve 1 are both three-position four-way proportional reversing valves, whose oil inlets are connected to the oil outlet of the hydraulic pump 4 via a pipeline, and the valve oil outlets are connected to the oil tank 6 via a pipeline, closing any of the two working oil ports of the valve.

[0019] The rodless chamber of the hydraulic cylinder 8 is connected to the unclosed working oil port of the rodless chamber proportional valve 2 through a pipeline, and the rod chamber is connected to the unclosed working oil port of the rod chamber proportional valve 1 through a pipeline. The two proportional valves can independently control the pressure and flow of the two oil chambers of the hydraulic cylinder 8, and the hydraulic cylinder 8 drives the suspension mechanism 9 to move.

[0020] The proportional relief valve 7 is connected to the oil inlet of the hydraulic pump 4 via a pipeline, and the overflow port is connected to the oil tank 6 via a pipeline. The proportional relief valve 7 controls the oil supply pressure of the hydraulic pump 4.

[0021] Energy saving in the suspension hydraulic circuit is achieved by:

[0022] The position sensor identifies the position information of the suspension mechanism 9 and determines the working condition of the agricultural implement connected to the suspension mechanism 9.

[0023] When the agricultural implement is in the standby stage, the tractor is in the working conditions of transporting, turning around, etc., the servo motor 3 does not work, and there is no energy loss in the hydraulic system at this stage.

[0024] When the agricultural machinery is in the lifting stage, the valve port of the proportional valve connected to the oil inlet of the hydraulic cylinder 8 is fully opened, the servo motor 3 drives the hydraulic pump 4 to control the flow, and the hydraulic pump 4 directly controls the movement of the hydraulic cylinder 8. The proportional valve connected to the oil outlet controls the oil chamber pressure to reduce the oil outlet chamber pressure as much as possible. At this stage, the pressure loss of the hydraulic system is minimized, the proportional relief valve 7 does not overflow, and there is almost no flow loss.

[0025] When the agricultural machinery is in the descending stage, the agricultural machinery descends by its own weight, and the valve port of the proportional valve connected to the oil outlet of the hydraulic cylinder 8 performs flow control to control the descending speed of the agricultural machinery. The valve port of the proportional valve connected to the oil inlet of the hydraulic cylinder 8 is fully opened, and the servo motor 3 drives the hydraulic pump 4 to only replenish the oil inlet chamber of the hydraulic cylinder 8. At this stage, there is no pressure loss in the hydraulic system, and work is only done by the gravity of the agricultural machinery. The proportional relief valve 7 does not overflow, and there is almost no flow loss.

[0026] When the agricultural machinery is in the operation stage, the tractor performs operations such as rotary tillage and spraying. The hydraulic cylinder 8 drives the agricultural machinery connected to the suspension mechanism 9 to perform position control. The servo motor 3 drives the hydraulic pump 4 to supply oil to the hydraulic system, and controls the proportional relief valve 7 to ensure that the oil supply pressure is only higher than a certain value of the load, thereby realizing the load-sensitive function. In order to ensure the operation quality of the agricultural machinery and improve the response speed of the hydraulic cylinder 8, the same command signal is input to the two proportional valves to simulate the mode of controlling the hydraulic cylinder with a single proportional valve. At this stage, the pressure loss of the hydraulic system is reduced.

[0027] The energy-saving hydraulic circuit of the electric tractor suspension device proposed in the utility model divides the operating conditions of the agricultural machinery connected to the suspension mechanism 9 into different stages, and proposes different energy-saving hydraulic circuit control methods for different stages, thereby improving the energy efficiency of the hydraulic system, thereby realizing energy-saving operation of the electric tractor suspension system.

[0028] The above description is only a preferred embodiment of the present invention, and does not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. An energy-saving hydraulic circuit for an electric tractor suspension device, comprising an oil tank (6), a filter (5), a hydraulic pump (4), a servo motor (3), a rodless chamber proportional valve (2), a rod chamber proportional valve (1), a proportional relief valve (7), a hydraulic cylinder (8) and a suspension mechanism (9), characterized in that: The hydraulic pump (4) is driven by a servo motor (3). The oil inlet of the hydraulic pump (4) is connected to a filter (5) via a pipeline. The filter (5) is connected to an oil tank (6) via a pipeline. The rodless chamber proportional valve (2) and the rod chamber proportional valve (1) are both three-position four-way proportional reversing valves. The oil inlet is connected to the oil outlet of the hydraulic pump (4) via a pipeline. The valve oil outlet is connected to an oil tank (6) via a pipeline. The valve closes any one of the two working oil ports. The rodless chamber of the hydraulic cylinder (8) is connected to an unclosed working oil port of the rodless chamber proportional valve (2) via a pipeline. The rod chamber is connected to an unclosed working oil port of the rod chamber proportional valve (1) via a pipeline. The hydraulic cylinder (8) drives the suspension mechanism (9) to move. The proportional overflow valve (7) is connected to the oil inlet of the hydraulic pump (4) via a pipeline. The overflow port is connected to the oil tank (6) via a pipeline.

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