A cutter head floating hydraulic control system based on constant pressure

Abstract

The present invention provides a cutter head floating hydraulic control system based on constant pressure, which includes a hydraulic supply mechanism, a pressure reducing valve, a pressure compensating valve, a three-position four-way proportional valve I, a three-position four-way proportional valve II, a double hydraulic control throttle valve, a double hydraulic control check valve, a cutter head lifting oil cylinder, a two-position four-way solenoid valve, and a pressure reducing overflow valve. The structure of the present invention is scientific and reasonable, which can make the cutter head have a good lifting and floating effect during cutting, and avoid the cutter head from being worn out too quickly due to touching the ground when cutting sugarcane.

Description

Technical Field

[0001] The present invention relates to the field of sugarcane harvesting equipment, and particularly relates to a floating hydraulic control system for a cutter head based on constant pressure. Background Art

[0002] Sugarcane is one of the important cash crops in southern China, and the sustainable development of the sugarcane industry is related to the strategic security of China's sugar.

[0003] At present, the cutting cutter heads of existing sugarcane laying machines are basically adjusted manually, with poor adjustment accuracy and unsatisfactory operation effects. The hydraulic system also mostly uses fixed displacement pumps and multi-way manual control valves for control. Although this reduces costs to some extent, it makes the overall machine operation complex, and various control valves are prone to confusion, causing potential safety hazards. At the same time, due to the general use of fixed displacement pumps in the existing technology, there will be relatively large flow losses and serious system heating, and due to the continuous change of the load, the working performance of the overall machine is also unreliable.

[0004] Therefore, adopting a suitable hydraulic system is one of the key technical problems to be solved for the automation and intelligence of current sugarcane harvesters. Summary of the Invention

[0005] The present invention aims to provide a floating hydraulic control system for a cutter head based on constant pressure. The floating hydraulic control system for a cutter head based on constant pressure has a scientific and reasonable structure, can make the cutter head have a good lifting and floating effect during cutting, and avoid the cutter head from wearing out too quickly due to touching the ground when cutting sugarcane.

[0006] The floating hydraulic control system for a cutter head based on constant pressure includes a hydraulic supply mechanism, a pressure reducing valve, a pressure compensating valve, a three-position four-way proportional valve I, a three-position four-way proportional valve II, a double hydraulic control throttle valve, a double hydraulic control check valve, a cutter head lifting oil cylinder, a two-position four-way solenoid valve, and a pressure reducing and overflow valve;

[0007] The oil outlet of the hydraulic supply mechanism is respectively connected to the P port of the pressure reducing valve and the P port of the pressure compensating valve; the T port of the pressure compensating valve is connected to the P port of the three-position four-way proportional valve I; the T port of the pressure reducing valve is connected to the unloading port of the three-position four-way proportional valve I;

[0008] The B port of the three-position four-way proportional valve I is connected to the P port of the three-position four-way proportional valve II, and the A port of the three-position four-way proportional valve I is connected to the P port of the pressure reducing and overflow valve;

[0009] The T port of the pressure reducing and overflow valve is connected to the P port of the two-position four-way solenoid valve, and the oil drain T port of the two-position four-way solenoid valve is connected to the fuel tank;

[0010] One end of the oil inlet of the double pilot-operated check valve is branched into two oil circuits. The oil inlet d is connected to the rodless cavity oil port of the cutter head lifting cylinder, and the oil inlet e is connected to the rod cavity oil port of the cutter head lifting cylinder. One end of the oil outlet of the double pilot-operated check valve is branched into two oil circuits. The oil outlet a is connected to an oil circuit to one end of the oil port e of the double pilot-operated throttle valve and the port A of the two-position four-way solenoid valve. The oil outlet b is connected to an oil circuit to the oil port f of the double pilot-operated throttle valve and the port B of the two-position four-way solenoid valve.

[0011] The three-position four-way proportional valve II, double pilot-operated throttle valve, double pilot-operated check valve, cutter head lifting cylinder, two-position four-way solenoid valve, and pressure relief overflow valve together form the cutter head floating control module.

[0012] The cutter head floating hydraulic control system based on constant pressure further includes a differential pressure relief valve, shuttle valve I, pressure limiting valve I, pressure limiting valve II, shuttle valve II, and shuttle valve III. The P port of the differential pressure relief valve is connected to the unloading port of the three-position four-way proportional valve I, and the T port of the differential pressure relief valve is connected to the oil tank. The oil pressure detection port A of the three-position four-way proportional valve I is connected to the P2 port of the shuttle valve II and the P port of the pressure limiting valve I. The oil pressure detection port B of the three-position four-way proportional valve I is connected to the P1 port of the shuttle valve II and the P port of the pressure limiting valve II. The oil pressure detection port of the pressure limiting valve I is connected to the LS signal detection port A. The T port of the pressure limiting valve II is connected to the oil tank, and the oil pressure detection port of the pressure limiting valve II is connected to the LS signal detection port B. The P2 port of the shuttle valve I is connected to the oil pressure detection port of the pressure compensation valve and the A port of the shuttle valve II. The P1 port of the shuttle valve I is connected to the oil tank, and the A port of the shuttle valve I is connected to the P1 port of the shuttle valve III. The P2 port of the shuttle valve III is connected to the return oil circuit pressure detection port, and the A port of the shuttle valve III is connected to the oil port signal X.

[0013] The pressure reducing valve, pressure compensation valve, three-position four-way proportional valve I, differential pressure relief valve, shuttle valve I, pressure limiting valve I, pressure limiting valve II, shuttle valve II, and shuttle valve III together form the PVG32 valve group.

[0014] The hydraulic supply mechanism includes a hydraulic variable pump, and the oil outlet of the hydraulic variable pump is the oil outlet of the hydraulic supply mechanism.

[0015] The hydraulic supply mechanism further includes a spring variable plunger cylinder, a non-spring variable plunger cylinder, a pressure control valve, and a flow control valve.

[0016] The described pressure control valve and flow control valve are both two-position three-way valves. One end of the oil outlet of the hydraulic variable pump is respectively connected to the first oil port of the pressure control valve and the first oil port of the flow control valve. The first oil port of the pressure control valve and the first oil port of the flow control valve are also simultaneously connected to the rodless cavity oil inlet of the springless variable plunger cylinder. The piston push rod of the springless variable plunger cylinder is connected to the front end of the oil outlet control of the hydraulic variable pump. The second oil port of the pressure control valve is connected to the rodless spring cavity oil inlet of the spring variable plunger cylinder. The piston push rod of the spring variable plunger cylinder is connected to the rear end of the oil outlet control of the hydraulic variable pump.

[0017] The first oil port of the described flow control valve is also simultaneously connected to the third oil port of the pressure control valve. The second oil port of the flow control valve is connected to the first oil port of the pressure control valve. The third oil port of the flow control valve is connected to the oil tank.

[0018] The hydraulic variable pump includes an oil outlet, a suction port S, a housing drain port L1, a housing drain port L2, a system pressure measurement port M2, a servo pressure measurement port M4, and a signal oil port X. The suction port S is connected to the oil tank through a filter. The system pressure measurement port M2 is used to measure the system pressure. The servo pressure measurement port M4 is used to measure the servo pressure. The signal oil port X is used to connect to shuttle valve Ⅰ to achieve variable oil supply. The system pressure measurement port M2 measures the system pressure by installing a system pressure gauge. The servo pressure measurement port M4 measures the servo pressure by installing a servo pressure gauge. The difference between the displayed value of the pressure gauge on port M2 and the pressure value on port X is the desired set value. The set value is the system pressure measured at port M2 minus the pilot control pressure at port X.

[0019] When the present invention works, when the signal tester at the system pressure measurement port M2 detects that the system pressure is lower than the set pressure of the pressure control valve, the right position of the pressure control valve works. The hydraulic variable pump adjusts the swash plate angle through the flow control valve to provide the required flow for the system. The outlet pressure of the hydraulic variable pump is always higher than the load pressure by a certain value. When the system pressure is higher than the set pressure of the pressure control valve, the left position of the pressure control valve works, cutting off the oil circuit between the flow control valve and the springless variable mechanism plunger cylinder. The high-pressure oil output by the hydraulic variable pump enters the rodless cavity of the spring variable mechanism plunger cylinder, making the swash plate angle of the hydraulic variable pump smaller until it approaches zero displacement, meeting the functional requirements of the hydraulic variable pump for outputting high-pressure and small flow under overload conditions, and reducing the power loss of the hydraulic system.

[0020] The flow rate of the hydraulic oil flowing through the valve core of the pressure regulating valve determines the pump pressure (waiting pressure) of the hydraulic variable pump. The highest load pressure is fed back to the spring cavity of the spring variable mechanism plunger cylinder behind the pressure control valve through the shuttle valve Ⅰ circuit, thereby completely or partially closing the oil return port. The pump pressure of the hydraulic variable pump is applied to the right side of the valve core of the pressure regulating valve. Once the load pressure exceeds the set value, the differential overflow valve will open, allowing a part of the pump flow to directly return to the hydraulic oil tank.

[0021] In the working module of the pressure compensating valve, whether the load changes or a module with a higher load pressure is driven, the pressure compensating valve can maintain the constant pressure drop of the main spool of the PVG32 valve bank. The buffer valve PVLP (with a fixed setting value) and the oil replenishing valve at the A / B ports are used to protect each working component during overload and / or when an air gap is generated. An adjustable pressure limiting valve is built into the A / B of the working module of the pressure compensating valve to limit the pressure of each working oil circuit.

[0022] The function of the pressure reducing valve is to provide the required control oil for the reversing valve of the PVG32 main valve body, that is, the three-position four-way proportional valve Ⅰ. The fixed-differential overflow valve mainly plays a protective role. When the system pressure increases, the flow demand decreases. At this time, the fixed-differential overflow valve opens, allowing the excess flow to return to the fuel tank to protect the constant inlet pressure of the fixed-differential overflow valve, that is, to protect the constant pump outlet pressure. On the right is the reversing connection. When the spool opening is fixed, the pressure difference before and after the fixed-differential overflow valve or the pressure compensating valve is constant. Then, when the flow rate at the B port of the hydraulic variable pump is greater than the flow rate of the three-position four-way proportional valve Ⅰ, the output flow rates at the A and B ports do not change with the output flow rate of the hydraulic variable pump and the load pressure. At this time, it is in a constant state. Above the spool are two proportional solenoids, and below is a handle, which can perform dual manual and automatic operations. The output ports A and B can both achieve load pressure feedback. The pressure limiting valve can achieve different controls for the pressures required by each actuator. Among the pressure servo sensor on the system pressure measuring port M2 and the load pressure sensor on the servo pressure measuring port M4, when several actuators work simultaneously, each actuator will generate a PLS pressure corresponding to its load size. The hydraulic adaptive adjustment system of the present invention needs to generate a pressure that at least meets the requirements of the maximum load. At this time, the shuttle valve Ⅲ compares the different PLS oil pressures in several modules and finally selects the maximum PLS oil pressure as the PLS oil pressure of the whole machine's hydraulic system and the control oil pressure of the PLS of the whole machine's hydraulic system, which acts on the pressure compensating valve and the hydraulic variable pump.

[0023] The present invention can make the cutter head have a good lifting and floating effect during cutting, and avoid the cutter head from wearing too fast due to touching the ground when cutting sugarcane. Description of the Drawings

[0024] Figure 1 is the hydraulic schematic diagram of the cutter head floating hydraulic control system based on pressure constancy in the embodiment;

[0025] The serial numbers and the structures and names of each part in the figure are as follows:

[0026] 1 - Hydraulic variable pump, 2 - Spring variable plunger cylinder, 3 - Springless variable plunger cylinder, 4 - Pressure control valve, 5 - Flow control valve, 6 - Fixed differential overflow valve, 7 - Pressure reducing valve, 8 - Pressure compensating valve, 9 - Shuttle valve Ⅰ, 10 - Pressure limiting valve Ⅰ, 11 - Pressure limiting valve Ⅱ, 12 - Three-position four-way proportional valve Ⅰ, 13 - Three-position four-way proportional valve Ⅱ, 14 - Double hydraulic control throttle valve, 15 - Double hydraulic control check valve, 16 - Cutter head lifting cylinder, 17 - Two-position four-way solenoid valve, 18 - Pressure reducing and overflow valve, 19 - Shuttle valve Ⅱ, 20 - Shuttle valve Ⅲ. Detailed implementation manner

[0027] The following describes an embodiment of the present invention in conjunction with the accompanying drawings:

[0028] As shown in the attached Figure 1 figure, the cutter head floating hydraulic control system based on constant pressure includes a hydraulic supply mechanism, a pressure reducing valve 7, a pressure compensating valve 8, a three-position four-way proportional valve Ⅰ 12, a three-position four-way proportional valve Ⅱ 13, a double hydraulic control throttle valve 14, a double hydraulic control check valve 15, a cutter head lifting cylinder 16, a two-position four-way solenoid valve 17, and a pressure reducing and overflow valve 18;

[0029] The oil outlet of the hydraulic supply mechanism is respectively connected to the P port of the pressure reducing valve 7 and the P port of the pressure compensating valve 8; the T port of the pressure compensating valve 8 is connected to the P port of the three-position four-way proportional valve Ⅰ 12; the T port of the pressure reducing valve 7 is connected to the unloading port of the three-position four-way proportional valve Ⅰ 12;

[0030] The B port of the three-position four-way proportional valve Ⅰ 12 is connected to the P port of the three-position four-way proportional valve Ⅱ 13, and the A port of the three-position four-way proportional valve Ⅰ 12 is connected to the P port of the pressure reducing and overflow valve 18;

[0031] The T port of the pressure reducing and overflow valve 18 is connected to the P port of the two-position four-way solenoid valve 17, and the oil discharge T port of the two-position four-way solenoid valve 17 is connected to the fuel tank;

[0032] One end of the oil inlet of the double hydraulic control check valve 15 is branched into two oil paths. The oil inlet d is connected to the rodless cavity oil port of the cutter head lifting cylinder 16, and the oil inlet e is connected to the rod cavity oil port of the cutter head lifting cylinder 16; one end of the oil outlet of the double hydraulic control check valve 15 is branched into two oil paths. The oil outlet a is connected to an oil path to one end of the oil port e of the double hydraulic control throttle valve 14 and the A port of the two-position four-way solenoid valve 17, and the oil outlet b is connected to an oil path to the oil port f of the double hydraulic control throttle valve 14 and the B port of the two-position four-way solenoid valve 17.

[0033] The three-position four-way proportional valve Ⅱ 13, the double hydraulic control throttle valve 14, the double hydraulic control check valve 15, the cutter head lifting cylinder 16, the two-position four-way solenoid valve 17, and the pressure reducing and overflow valve 18 jointly form a cutter head floating control module.

[0034] The described cutter head floating hydraulic control system based on constant pressure further includes a fixed differential overflow valve 6, shuttle valve I 9, pressure limiting valve I 10, pressure limiting valve II 11, shuttle valve II 19, and shuttle valve III 20. The P port of the fixed differential overflow valve 6 is connected to the unloading port of the three-position four-way proportional valve I 12, and the T port of the fixed differential overflow valve 6 is connected to the oil tank. The oil pressure detection A port of the three-position four-way proportional valve I 12 is connected to the P2 port of the shuttle valve II 19 and the P port of the pressure limiting valve I 10, and the oil pressure detection B of the three-position four-way proportional valve I 12 is connected to the P1 port of the shuttle valve II 19 and the P port of the pressure limiting valve II 11. The oil pressure detection port of the pressure limiting valve I 10 is connected to the LS signal detection A port. The T port of the pressure limiting valve II 11 is connected to the oil tank, and the oil pressure detection port of the pressure limiting valve II 11 is connected to the LS signal detection B port. The P2 port of the shuttle valve I 9 is connected to the oil pressure detection port of the pressure compensation valve 8 and the A port of the shuttle valve II 19, the P1 port of the shuttle valve I 9 is connected to the oil tank, and the A port of the shuttle valve I 9 is connected to the P1 port of the shuttle valve III 20. The P2 port of the shuttle valve III 20 is connected to the return oil circuit oil pressure detection port, and the A port of the shuttle valve III 20 is connected to the oil port signal X.

[0035] The described pressure reducing valve 7, pressure compensation valve 8, three-position four-way proportional valve I 12, fixed differential overflow valve 6, shuttle valve I 9, pressure limiting valve I 10, pressure limiting valve II 11, shuttle valve II 19, and shuttle valve III 20 together form a PVG32 valve group.

[0036] The described hydraulic supply mechanism includes a hydraulic variable pump 1, and the oil outlet of the hydraulic variable pump 1 is the oil outlet of the hydraulic supply mechanism.

[0037] The described hydraulic supply mechanism further includes a spring variable plunger cylinder 2, a non-spring variable plunger cylinder 3, a pressure control valve 4, and a flow control valve 5.

[0038] Both the described pressure control valve 4 and the flow control valve 5 are two-position three-way valves. One end of the oil outlet of the hydraulic variable pump 1 is respectively connected to the first oil port of the pressure control valve 4 and the first oil port of the flow control valve 5. The first oil ports of the pressure control valve 4 and the flow control valve 5 are also simultaneously connected to the oil inlet of the rodless cavity of the non-spring variable plunger cylinder 3, and the piston push rod of the non-spring variable plunger cylinder 3 is connected to the front end of the oil outlet control of the hydraulic variable pump 1. The second oil port of the pressure control valve 4 is connected to the oil inlet of the rodless spring cavity of the spring variable plunger cylinder 2, and the piston push rod of the spring variable plunger cylinder 2 is connected to the rear end of the oil outlet control of the hydraulic variable pump 1.

[0039] The first oil port of the described flow control valve 5 is also simultaneously connected to the third oil port of the pressure control valve 4. The second oil port of the flow control valve 5 is connected to the first oil port of the pressure control valve 4, and the third oil port of the flow control valve 5 is connected to the oil tank.

[0040] The hydraulic variable pump 1 includes an oil outlet, a suction port S, a housing oil drain port L1, a housing oil drain port L2, a system pressure measurement port M2, a servo pressure measurement port M4, and a signal oil port X; the suction port S is connected to the fuel tank through a filter, the system pressure measurement port M2 is used to measure the system pressure, the servo pressure measurement port M4 is used to measure the servo pressure, and the signal oil port X is used to connect to the shuttle valve I 9 to achieve variable oil supply.

Claims

1. A cutter head floating hydraulic control system based on constant pressure, comprising a hydraulic supply mechanism, a pressure reducing valve (7), a pressure compensating valve (8), a three-position four-way proportional valve I (12), a three-position four-way proportional valve II (13), a double hydraulic control throttle valve (14), a double hydraulic control check valve (15), a cutter head lifting oil cylinder (16), a two-position four-way solenoid valve (17), and a pressure reducing and overflow valve (18). It is characterized in that: The oil outlets of the hydraulic supply mechanism are respectively connected to the P port of the pressure reducing valve (7) and the P port of the pressure compensating valve (8); the T port of the pressure compensating valve (8) is connected to the P port of the three-position four-way proportional valve I (12); the T port of the pressure reducing valve (7) is connected to the unloading port of the three-position four-way proportional valve I (12). The B port of the three-position four-way proportional valve I (12) is connected to the P port of the three-position four-way proportional valve II (13), and the A port of the three-position four-way proportional valve I (12) is connected to the P port of the pressure reducing and overflow valve (18). The T port of the pressure reducing and overflow valve (18) is connected to the P port of the two-position four-way solenoid valve (17), and the drain T port of the two-position four-way solenoid valve (17) is connected to the oil tank. One end of the oil inlet of the double hydraulic control check valve (15) is separated into two oil circuits. The oil inlet d is connected to the rodless cavity oil port of the cutter head lifting oil cylinder (16), and the oil inlet e is connected to the rod cavity oil port of the cutter head lifting oil cylinder (16); one end of the oil outlet of the double hydraulic control check valve (15) is separated into two oil circuits. The oil outlet a is connected to an oil circuit to one end of the oil port e of the double hydraulic control throttle valve (14) and the A port of the two-position four-way solenoid valve (17), and the oil outlet b is connected to an oil circuit to the oil port f of the double hydraulic control throttle valve (14) and the B port of the two-position four-way solenoid valve (17). It further includes a fixed differential overflow valve (6), a shuttle valve I (9), a pressure limiting valve I (10), a pressure limiting valve II (11), a shuttle valve II (19), and a shuttle valve III (20). The P port of the fixed differential overflow valve (6) is connected to the unloading port of the three-position four-way proportional valve I (12), and the T port of the fixed differential overflow valve (6) is connected to the oil tank; the oil pressure detection A port of the three-position four-way proportional valve I (12) is connected to the P2 port of the shuttle valve II (19) and the P port of the pressure limiting valve I (10), and the oil pressure detection B of the three-position four-way proportional valve I (12) is connected to the P1 port of the shuttle valve II (19) and the P port of the pressure limiting valve II (11); the oil pressure detection port of the pressure limiting valve I (10) is connected to the LS signal detection A port; the T port of the pressure limiting valve II (11) is connected to the oil tank, and the oil pressure detection port of the pressure limiting valve II (11) is connected to the LS signal detection B port; the P2 port of the shuttle valve I (9) is connected to the oil pressure detection port of the pressure compensating valve (8) and the A port of the shuttle valve II (19), the P1 port of the shuttle valve I (9) is connected to the oil tank, and the A port of the shuttle valve I (9) is connected to the P1 port of the shuttle valve III (20); the P2 port of the shuttle valve III (20) is connected to the return oil circuit pressure detection port, and the A port of the shuttle valve III (20) is connected to the oil port signal X. The hydraulic supply mechanism includes a hydraulic variable pump (1), and the oil outlet of the hydraulic variable pump (1) is the oil outlet of the hydraulic supply mechanism. The hydraulic supply mechanism further includes a spring variable plunger cylinder (2), a non-spring variable plunger cylinder (3), a pressure control valve (4), and a flow control valve (5). The hydraulic variable pump (1) includes an oil outlet, a suction port S, a housing oil drain port L1, a housing oil drain port L2, a system pressure measurement port M2, a servo pressure measurement port M4, and a signal oil port X. The suction port S is connected to the fuel tank through a filter. The system pressure measurement port M2 is used to measure the system pressure. The servo pressure measurement port M4 is used to measure the servo pressure. The signal oil port X is used to connect to the shuttle valve I (9) to achieve variable oil supply.

2. The cutter head floating hydraulic control system based on constant pressure according to claim 1, characterized in that: The three-position four-way proportional valve II (13), the double hydraulic control throttle valve (14), the double hydraulic control check valve (15), the cutter head lifting oil cylinder (16), the two-position four-way solenoid valve (17), and the pressure reducing overflow valve (18) together form a cutter head floating control module.

3. The cutter head floating hydraulic control system based on constant pressure according to claim 1, characterized in that: The pressure reducing valve (7), the pressure compensation valve (8), the three-position four-way proportional valve I (12), the fixed-difference overflow valve (6), the shuttle valve I (9), the pressure limiting valve I (10), the pressure limiting valve II (11), the shuttle valve II (19), and the shuttle valve III (20) together form a PVG32 valve group.

4. The cutter head floating hydraulic control system based on constant pressure according to claim 1, characterized in that: Both the pressure control valve (4) and the flow control valve (5) are two-position three-way valves. One end of the oil outlet of the hydraulic variable pump (1) is respectively connected to the first oil port of the pressure control valve (4) and the first oil port of the flow control valve (5). The first oil ports of the pressure control valve (4) and the flow control valve (5) are also simultaneously connected to the oil inlet of the rodless cavity of the non-spring variable plunger cylinder (3). The piston push rod of the non-spring variable plunger cylinder (3) is connected to the front end of the oil outlet control of the hydraulic variable pump (1). The second oil port of the pressure control valve (4) is connected to the oil inlet of the rodless spring cavity of the spring variable plunger cylinder (2). The piston push rod of the spring variable plunger cylinder (2) is connected to the rear end of the oil outlet control of the hydraulic variable pump (1). The first oil port of the flow control valve (5) is also simultaneously connected to the third oil port of the pressure control valve (4). The second oil port of the flow control valve (5) is connected to the first oil port of the pressure control valve (4). The third oil port of the flow control valve (5) is connected to the fuel tank.

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