Tractor electric control lifter control system

Abstract

The utility model discloses a tractor electric control lifter control system, which belongs to the technical field of tractor lifter control systems, and comprises a pressure compensation valve, a proportional reversing valve, a shuttle valve and a lifting oil cylinder, a system oil inlet is communicated with a first oil port of the proportional reversing valve, a second oil port of the proportional reversing valve is communicated with a rodless cavity of the lifting oil cylinder, and the pressure compensation valve is connected with the shuttle valve. A third oil port of the proportional reversing valve is communicated with a rod cavity of the lifting oil cylinder, and a fourth oil port of the proportional reversing valve is communicated with the oil return port; an oil inlet and a first control oil port of the pressure compensation valve are respectively communicated with a system oil inlet, an oil overflow port of the pressure compensation valve is communicated with a bypass oil port, two oil inlets of the shuttle valve are respectively communicated with a second oil port and a third oil port, and an oil outlet of the shuttle valve is communicated with a second control oil port of the pressure compensation valve. The pressure compensation valve can collect load pressure signals through the shuttle valve and can automatically adjust the flow input into a system according to the opening degree of the proportional reversing valve under various working conditions, and therefore energy waste is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of tractor lift control systems, and particularly relates to an electric control lift control system for tractors. Background Art

[0002] Tractors are essential mechanical equipment in agricultural production and can be used for tilling, sowing, fertilizing, transporting, etc., for towing and driving working machinery to complete various mobile operations. The tractor controls the lifting of the lift through a hydraulic system to adjust the attitude of agricultural implements. However, the flow rate of the hydraulic oil input to the existing lift cannot be automatically adjusted according to various working conditions, resulting in relatively large heat generation and serious energy waste. Content of the Utility Model

[0003] The technical problem to be solved by the utility model is to provide an electric control lift control system for tractors, which can automatically adjust the flow rate input to the system according to the opening degree of the proportional directional valve under various working conditions and reduce energy waste.

[0004] To solve the above technical problem, the technical solution of the utility model is as follows:

[0005] An electric control lift control system for tractors includes: a pressure compensation valve, a proportional directional valve, a shuttle valve, and a lift cylinder. The system inlet is communicated with the first oil port of the proportional directional valve. The second oil port of the proportional directional valve is communicated with the rodless cavity of the lift cylinder. The third oil port of the proportional directional valve is communicated with the rod cavity of the lift cylinder. The fourth oil port of the proportional directional valve is communicated with the oil return port. A proportional valve is connected between the second oil port and the rodless cavity of the lift cylinder. When the electromagnet of the proportional valve is de-energized, its valve is unidirectionally fully open and conducting from the proportional directional valve to the lift cylinder. When the electromagnet of the proportional valve is energized, the opening degree of its valve is proportional to the input current. The inlet and the first control oil port of the pressure compensation valve are respectively communicated with the system inlet. The oil spill port of the pressure compensation valve is communicated with the bypass oil port. The two inlet ports of the shuttle valve are respectively communicated with the second oil port and the third oil port. The outlet port of the shuttle valve is communicated with the second control oil port of the pressure compensation valve.

[0006] Further, a throttle valve is arranged on the pipeline between the shuttle valve and the pressure compensation valve.

[0007] Further, the proportional directional valve includes a first electromagnet and a second electromagnet. When the first electromagnet is energized, the first oil port is communicated with the second oil port. When the second electromagnet is energized, the first oil port is communicated with the third oil port. When both the first electromagnet and the second electromagnet are de-energized, the second oil port, the fourth oil port, and the fourth oil port are communicated.

[0008] Furthermore, a make-up valve is provided on the pipeline between the rod chamber of the lifting oil cylinder and the oil return port.

[0009] Furthermore, the make-up valve is a one-way valve that conducts from the oil return port to the rod chamber of the lifting oil cylinder.

[0010] Furthermore, a relief valve is provided on the pipeline between the rodless chamber of the lifting oil cylinder and the oil return port.

[0011] Furthermore, a proportional relief valve is provided on the pipeline between the rod chamber of the lifting oil cylinder and the oil return port.

[0012] Furthermore, two lifting oil cylinders are provided, and the rod chambers and rodless chambers of the two lifting oil cylinders are respectively communicated with the corresponding oil ports of the proportional directional valve.

[0013] After adopting the above technical solution, the beneficial effects of the present utility model are as follows:

[0014] Since the control system of the tractor electric lifting device of the present utility model includes: a pressure compensation valve, a proportional directional valve, a shuttle valve and a lifting oil cylinder, the system oil inlet is communicated with the first oil port of the proportional directional valve, the second oil port of the proportional directional valve is communicated with the rodless chamber of the lifting oil cylinder, the third oil port of the proportional directional valve is communicated with the rod chamber of the lifting oil cylinder, and the fourth oil port of the proportional directional valve is communicated with the oil return port; the oil inlet and the first control oil port of the pressure compensation valve are respectively communicated with the system oil inlet, the oil spill port of the pressure compensation valve is communicated with the bypass oil port, the two oil inlets of the shuttle valve are respectively communicated with the second oil port and the third oil port, the oil outlet of the shuttle valve is communicated with the second control oil port of the pressure compensation valve, and the pressure compensation valve can collect the load pressure signal through the shuttle valve and can automatically adjust the flow rate input into the system according to the opening of the proportional directional valve under various working conditions, thereby reducing energy waste. Description of the Drawings

[0015] Figure 1 is a schematic structural diagram of the control system of the tractor electric lifting device of the present utility model;

[0016] In the figure, 1 - control system, 11 - system oil inlet, 12 - oil return port, 13 - bypass oil port, 2 - pressure compensation valve, 2a - first control oil port, 2b - second control oil port, 2c - oil spill port, 21 - throttle valve, 3 - proportional directional valve, 3a - first oil port, 3b - second oil port, 3c - third oil port, 3d - fourth oil port, 4 - shuttle valve, 5 - proportional valve, 6 - relief valve, 7 - lifting oil cylinder, 71 - rod chamber, 72 - rodless chamber, 8 - make-up valve, 9 - proportional relief valve. Detailed Embodiments

[0017] The present utility model will be further described below in conjunction with the accompanying drawings and embodiments. The preferred embodiments of the present utility model are shown in the drawings. The role of the drawings is to supplement the description in the text part of the specification, enabling people to intuitively and vividly understand each technical feature and the overall technical solution of the present utility model. However, it should not be construed as a limitation on the protection scope of the present utility model.

[0018] As Figure 1 shown, a control system for an electronic lift of a tractor includes: a pressure compensation valve 2, a proportional directional valve 3, a shuttle valve 4, and a lift cylinder 7. The system inlet port 11 is communicated with the first oil port 3a of the proportional directional valve 3. The second oil port 3b of the proportional directional valve 3 is communicated with the rodless cavity 72 of the lift cylinder 7. The third oil port 3c of the proportional directional valve 3 is communicated with the rod cavity 71 of the lift cylinder 7. The fourth oil port 3d of the proportional directional valve 3 is communicated with the oil return port 12 of the control system 1. In this application, two lift cylinders 7 are provided. The rod cavities 71 and the rodless cavities 72 of the two lift cylinders 7 are respectively communicated with the corresponding oil ports of the proportional directional valve 3. The hydraulic oil in the fuel tank is pressurized by an oil pump and input into the rod cavity 71 and the rodless cavity 72 through the inlet port 11. The oil return under each working condition flows back to the fuel tank through the oil return port 12.

[0019] A proportional valve 5 is connected between the second oil port 3b and the rodless cavity 72 of the lift cylinder 7. During the upward movement of the agricultural implement, the electromagnet S3 of the proportional valve 5 is not energized, and its valve is unidirectionally fully opened and conducted from the proportional directional valve 3 to the lift cylinder 7. During the self-weight descent and forced descent of the agricultural implement, the electromagnet S3 of the proportional valve 5 is energized, and the opening of its valve is proportional to the input current. By adjusting the input current to the electromagnet S3, the opening of the valve can be adjusted, and further the discharge speed of the hydraulic oil in the rodless cavity 72 of the lift cylinder 7 can be adjusted, and the retraction speed of the lift cylinder 7 can be adjusted, thereby adjusting the descent speed of the agricultural implement. When the agricultural implement reaches the target position, the valve of the proportional valve 5 closes, and the hydraulic oil in the rodless cavity 72 of the lift cylinder 7 no longer flows out.

[0020] The oil inlet of the pressure compensation valve 2 and the first control oil port 2a are respectively connected to the system oil inlet 11. The oil spill port 2c of the pressure compensation valve 2 is connected to the bypass oil port 13 of the control system 1. The two oil inlets of the shuttle valve 4 are respectively connected to the second oil port 3b and the third oil port 3c. The oil outlet of the shuttle valve 4 is connected to the second control oil port 2b of the pressure compensation valve 2. Since the second oil port 3b and the third oil port 3c are respectively connected to the rod chamber 71 and the rodless chamber 72 of the lifting cylinder 7, the two oil inlets of the shuttle valve 4 can respectively collect the pressures of the rod chamber 71 and the rodless chamber 72 of the lifting cylinder 7. The larger pressure signal among the two pressures is transmitted to the second control oil port 2b of the pressure compensation valve 2. The pressure compensation valve 2 compares this pressure signal with the oil delivery pressure of the oil inlet 11 collected by its first control oil port 2a, and controls the valve opening according to the size of the pressure difference, so that part of the hydraulic oil is discharged through the oil spill port 2c to the bypass oil port 13. The bypass oil port 13 is connected to the multi-way valve to supply oil to other equipment of the hydraulic system.

[0021] The specific size of the pressure signal collected by the second control oil port 2b of the pressure compensation valve 2 is related to the valve opening of the proportional directional valve 3. The pressure compensation valve 2 compensates the system inlet oil pressure according to the opening of the proportional directional valve 3 under various working conditions, controls the flow rate input to the system, and then controls the lifting speed of the lifting cylinder 7, thereby reducing energy waste.

[0022] A throttle valve 21 is provided on the pipeline between the shuttle valve 4 and the pressure compensation valve 2 to control the flow rate of the hydraulic oil flowing through the throttle valve 21 and buffer the influence of the system pressure on the pressure compensation valve 2.

[0023] The proportional directional valve 3 includes a first electromagnet S1 and a second electromagnet S2. When the agricultural implement is lifted and the first electromagnet S1 is energized, the spool moves to the left position, and the first oil port 3a is communicated with the second oil port 3b. The hydraulic oil input from the system oil inlet 11 is input to the rodless chamber 72 through the proportional directional valve 3, and the piston rod of the lifting cylinder 7 extends. To ensure the tillage depth in the case of poor soil conditions, during the strong pressure descent working condition of the agricultural implement, the second electromagnet S2 is energized, the spool moves to the right position, and the first oil port 3a is communicated with the third oil port 3c. The hydraulic oil input from the system oil inlet 11 is input to the rod chamber 71 of the lifting cylinder 7 through the proportional directional valve 3. When the agricultural implement descends under its own weight, neither the first electromagnet S1 nor the second electromagnet S2 is energized, the spool is in the middle position, the second oil port 3b and the fourth oil port 3d are communicated with the fourth oil port 3d, and the hydraulic oil in the rodless chamber 72 is preferentially replenished to the rod chamber 71 through the proportional directional valve 3, and the excess hydraulic oil flows to the oil return port 12.

[0024] A make-up valve 8 is provided on the pipeline between the rod chamber 71 of the lifting cylinder 7 and the oil return port 12. During the process of the agricultural implement descending due to its own weight, if the hydraulic oil overflowing from the rodless chamber 72 of the lifting cylinder 7 cannot meet the requirements of the rod chamber 71, the hydraulic oil in the fuel tank flows in through the oil return port 12 and is used for emergency make-up oil for the rod chamber 71 of the lifting cylinder 7 through the make-up valve 8. Specifically, the make-up valve 8 is a one-way valve that conducts from the oil return port 12 to the rod chamber 71 of the lifting cylinder 7.

[0025] An overflow valve 6 is provided on the pipeline between the rodless chamber 72 of the lifting cylinder 7 and the oil return port 12. When the tractor is transporting during a transfer on the road surface, the uneven road surface will cause the agricultural implement to vibrate up and down. The electromagnet S3 of the proportional valve 5 is not energized, and the hydraulic oil in the rodless chamber 72 cannot flow out through the proportional valve 5. When the pressure in the rodless chamber 72 of the lifting cylinder 7 is too high and the pressure of the hydraulic oil in the rodless chamber 72 exceeds the opening pressure of the overflow valve 6, the overflow valve 6 opens, and the excess hydraulic oil flows out through the oil return port 12 to prevent damage to the internal components due to excessive pressure in the rodless chamber 72.

[0026] A proportional overflow valve 9 is provided on the pipeline between the rod chamber 71 of the lifting cylinder 7 and the oil return port 12. The proportional overflow valve 9 has two states. When the electromagnet S4 is not energized, the pressure in the rod chamber 71 exceeds the opening pressure of the proportional overflow valve 9, and the proportional overflow valve 9 opens. When the electromagnet S4 is energized, the opening pressure of the proportional overflow valve 9 changes proportionally according to the input current. During the strong pressure descent process of the agricultural implement, hydraulic oil is filled into the rod chamber 71. At this time, the solenoid valve S4 is energized, and the hydraulic oil exceeding the opening pressure of the proportional overflow valve 9 flows out. By adjusting the input current of the solenoid valve S4, the opening pressure of the proportional overflow valve 9 can be adjusted, thereby adjusting the pressure in the rod chamber 71 of the lifting cylinder 7 and realizing the adjustment of the downward pressure during the strong pressure descent process.

[0027] The control system of the tractor's electric lifting device of the present utility model reduces energy waste by setting a pressure compensation valve, a proportional reversing valve and a shuttle valve connected to the lifting cylinder. The inlet port and the first control port of the pressure compensation valve are respectively connected to the inlet port of the lift, the oil spill port is connected to the bypass port of the lift, the two inlet ports of the shuttle valve are respectively connected to the second port and the third port, and the outlet port of the shuttle valve is connected to the second control port of the pressure compensation valve. The pressure compensation valve can collect the load pressure signal through the shuttle valve and automatically adjust the flow rate input to the system according to the opening degree of the proportional reversing valve under various working conditions.

[0028] In the description of this specification, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features.

[0029] In the description of this specification, unless otherwise clearly defined, words such as "set", "installed", "connected", etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in this utility model in combination with the specific content of the technical solution.

[0030] Although the specific implementation manners of the present utility model have been described above, those skilled in the art should understand that the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. These are only illustrative examples, and the protection scope of the present utility model is defined by the claims. Without departing from the principle and essence of the present utility model, those skilled in the art can make various changes or modifications to these implementation manners without any creative labor, but these changes and modifications all fall within the protection scope of the present utility model.

Claims

1. A tractor electric lift control system, characterized in that: include: A pressure compensation valve, a proportional reversing valve, a shuttle valve, a proportional valve and a lifting cylinder, wherein the system oil inlet is connected to the first oil port of the proportional reversing valve, the second oil port of the proportional reversing valve is connected to the rodless chamber of the lifting cylinder, the third oil port of the proportional reversing valve is connected to the rod chamber of the lifting cylinder, and the fourth oil port of the proportional reversing valve is connected to the oil return port; A proportional valve is connected between the second oil port and the rodless chamber of the lifting oil cylinder. When the electromagnet of the proportional valve is not energized, the valve is fully opened in one direction from the proportional reversing valve to the lifting oil cylinder. When the electromagnet of the proportional valve is energized, the valve opening is proportional to the input current. The oil inlet and the first control oil port of the pressure compensating valve are respectively connected to the system oil inlet, the oil overflow port of the pressure compensating valve is connected to the bypass oil port, the two oil inlets of the shuttle valve are respectively connected to the second oil port and the third oil port, and the oil outlet of the shuttle valve is connected to the second control oil port of the pressure compensating valve.

2. The tractor electric lift control system according to claim 1, characterized in that: A throttle valve is arranged on the pipeline between the shuttle valve and the pressure compensating valve.

3. The tractor electric lift control system according to claim 1, characterized in that: The proportional reversing valve includes a first electromagnet and a second electromagnet. When the first electromagnet is energized, the first oil port is connected to the second oil port; when the second electromagnet is energized, the first oil port is connected to the third oil port; when the first electromagnet and the second electromagnet are not energized, the second oil port, the fourth oil port and the fourth oil port are connected.

4. The tractor electric lift control system according to claim 1, characterized in that: An oil replenishing valve is arranged on the pipeline between the rod chamber of the lifting oil cylinder and the oil return port.

5. The tractor electric lift control system according to claim 4, characterized in that: The oil replenishing valve is a one-way valve that conducts from the oil return port to the rod chamber of the lifting cylinder.

6. The tractor electric lift control system according to claim 1, characterized in that: An overflow valve is arranged on the pipeline between the rodless chamber of the lifting cylinder and the oil return port.

7. The tractor electric lift control system according to claim 1, characterized in that: A proportional overflow valve is arranged on the pipeline between the rod chamber of the lifting cylinder and the oil return port.

8. The tractor electric lift control system according to any one of claims 1 to 7, characterized in that: The lifting oil cylinders are provided with two, and the rod chambers and rodless chambers of the two lifting oil cylinders are respectively communicated with the corresponding oil ports of the proportional reversing valve.

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