A high-low voltage automatic switching control logic device, system and its control method

Abstract

The present invention discloses a high-low pressure automatic switching control logic device, which includes a first control logic unit, a second control logic unit, and a control oil port assembly; the first control logic unit is connected to the second control logic unit through the control oil port assembly. The present invention also proposes a high-low pressure automatic switching control logic system, which includes a hydraulic system and a high-low pressure automatic switching control logic device, and the oil ports of the hydraulic system are respectively connected to the first control logic unit and the second control logic unit. The present invention also proposes a control method for a high-low pressure automatic switching control logic system, which includes: a low-pressure pumping control step; a high-pressure pumping control step. By designing a high-low pressure switching system with a new control logic, the present invention enables the concrete pump to easily achieve the switching from low pressure to high pressure (or from high pressure to low pressure) within a short period of time, thereby improving the construction efficiency of the concrete pump, reducing the construction intensity of workers, and enhancing the overall performance of the concrete pump.

Description

Technical Field

[0001] The present invention relates to a high - low pressure automatic switching control logic device, system and its control method, belonging to the technical field of high - low pressure automatic control. Background Art

[0002] With the development of society, high - rise buildings are becoming more and more common. The rise of high - rise buildings provides new development opportunities for our concrete pumping industry, but also brings new challenges. At present, major domestic concrete pumping machinery manufacturers are all making great efforts to develop high - pressure pumping equipment.

[0003] The prior art realizes the commutation logic of high - low pressure switching through four three - position four - way electromagnetic reversing valves. There are many pipelines, which is not conducive to integration and occupies a large space. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defects of the prior art, and provide a high - low pressure automatic switching control logic device, system and its control method. By developing a high - low pressure switching control logic system with a new control logic, the concrete pump can easily achieve the switching from low pressure to high pressure (or from high pressure to low pressure) in a short time, thereby improving the construction efficiency of the concrete pump, reducing the construction intensity of workers, and enhancing the overall performance of the concrete pump.

[0005] To solve the above - mentioned technical problem, the present invention provides a high - low pressure automatic switching control logic device, which is characterized by comprising a first control logic unit, a second control logic unit and a control oil port assembly; the first control logic unit is connected to the second control logic unit through the control oil port assembly;

[0006] The control oil port assembly includes a first control oil port Kz1, a second control oil port Kz2, a third control oil port Kz3 and a fourth control oil port Kz4;

[0007] The first control logic unit includes a first pressure oil port Pd, a first pilot - operated check valve V1, a second pilot - operated check valve V2, a third pilot - operated check valve V3, a fourth pilot - operated check valve V4, and a first cartridge valve control oil port P5. The first pressure oil port Pd is respectively connected to the first cartridge valve control oil port P5, the control oil circuit of the first pilot - operated check valve V1, the control oil circuit of the second pilot - operated check valve V2, the control oil circuit of the third pilot - operated check valve V3, and the control oil circuit of the fourth pilot - operated check valve V4;

[0008] The second control logic unit includes a second pressure oil port Pg, a fifth pilot-operated check valve V5, a sixth pilot-operated check valve V6, a seventh pilot-operated check valve V7, an eighth pilot-operated check valve V8, and a second cartridge valve control oil port P6. The second pressure oil port Pg is respectively connected to the second cartridge valve control oil port P6, the control oil circuit of the fifth pilot-operated check valve V5, the control oil circuit of the sixth pilot-operated check valve V6, the control oil circuit of the seventh pilot-operated check valve V7, and the control oil circuit of the eighth pilot-operated check valve V8.

[0009] The first control oil port Kz1 is respectively connected to the oil outlet of the first pilot-operated check valve V1 and the oil outlet of the fifth pilot-operated check valve V5. The second control oil port Kz2 is respectively connected to the oil outlet of the fourth pilot-operated check valve V4 and the oil outlet of the eighth pilot-operated check valve V8. The third control oil port Kz3 is respectively connected to the oil outlet of the second pilot-operated check valve V2 and the oil outlet of the sixth pilot-operated check valve V6. The fourth control oil port Kz4 is respectively connected to the oil outlet of the third pilot-operated check valve V3 and the oil outlet of the seventh pilot-operated check valve V7.

[0010] The present invention also provides a high-low pressure automatic switching control logic system, which includes a hydraulic system and a high-low pressure automatic switching control logic device. The oil ports of the hydraulic system are respectively connected to the first control logic unit and the second control logic unit.

[0011] As a preferred embodiment, the hydraulic system includes a first three-position four-way directional control valve 1, a second three-position four-way directional control valve 2, a first spool valve 3, a second spool valve 4, a first cartridge valve 5, a second cartridge valve 6, a first oil cylinder 7, and a second oil cylinder 8. The first three-position four-way directional control valve 1, the second three-position four-way directional control valve 2, the first spool valve 3, and the second spool valve 4 are all spool valves. The first cartridge valve 5 is respectively connected to the rod chamber of the first oil cylinder 7, the rod chamber of the second oil cylinder 8, and the first spool valve 3. The first spool valve 3 is connected to the second three-position four-way directional control valve 2. The second cartridge valve 6 is respectively connected to the rodless chamber of the first oil cylinder 7, the rodless chamber of the second oil cylinder 8, and the second spool valve 4. The second spool valve 4 is connected to the first three-position four-way directional control valve 1. The first three-position four-way directional control valve 1 and the second three-position four-way directional control valve 2 are externally connected to the pumped high-pressure oil through the P port.

[0012] As a preferred embodiment, the spools of the first three-position four-way directional control valve 1, the second three-position four-way directional control valve 2, the first slide valve 3 and the second slide valve 4 are arranged in a flat layout, and the first pilot-operated check valve V1, the second pilot-operated check valve V2, the third pilot-operated check valve V3, the fourth pilot-operated check valve V4, the fifth pilot-operated check valve V5, the sixth pilot-operated check valve V6, the seventh pilot-operated check valve V7 and the eighth pilot-operated check valve V8 form four groups of pilot-operated check valves and are distributed at both ends; or the spools of the first three-position four-way directional control valve 1, the second three-position four-way directional control valve 2, the first slide valve 3 and the second slide valve 4 are arranged in two layers, front and back, and the first pilot-operated check valve V1, the second pilot-operated check valve V2, the third pilot-operated check valve V3, the fourth pilot-operated check valve V4, the fifth pilot-operated check valve V5, the sixth pilot-operated check valve V6, the seventh pilot-operated check valve V7 and the eighth pilot-operated check valve V8 form four groups of pilot-operated check valves and are arranged at one end.

[0013] As a preferred embodiment, the first three-position four-way directional control valve, the second three-position four-way directional control valve, the first slide valve and the second slide valve are all slide valves.

[0014] As a preferred embodiment, the first three-position four-way directional control valve 1 is respectively connected to the oil inlet of the fifth pilot-operated check valve V5 and the oil inlet of the eighth pilot-operated check valve V8; the second three-position four-way directional control valve 2 is respectively connected to the oil inlet of the first pilot-operated check valve V1 and the oil inlet of the fourth pilot-operated check valve V4; the first slide valve 3 is respectively connected to the oil inlet of the second pilot-operated check valve V2 and the oil inlet of the third pilot-operated check valve V3; the second slide valve 4 is respectively connected to the oil inlet of the sixth pilot-operated check valve V6 and the oil inlet of the seventh pilot-operated check valve V7.

[0015] As a preferred embodiment, the first cartridge valve 5 is connected to the first pressure oil port Pd through the control oil port P5 of the first cartridge valve; the second cartridge valve 6 is connected to the second pressure oil port Pg through the control oil port P6 of the second cartridge valve.

[0016] As a preferred embodiment, a circulating oil circuit for low-pressure pumping includes: the high-pressure pumping oil input at the P port sequentially enters the rod chamber of the first oil cylinder 7 through the second three-position four-way directional control valve 2 and the first slide valve 3, and the pressure oil in the rodless chamber of the first oil cylinder 7 enters the rodless chamber of the second oil cylinder 8 through the second cartridge valve 6, and the pressure oil in the rod chamber of the second oil cylinder 8 passes through the first slide valve 3 and the second three-position four-way directional control valve 2 and is output to the T port; the high-pressure pumping oil at the P port sequentially passes through the second three-position four-way directional control valve 2 and the first slide valve 3 and enters the rod chamber of the second oil cylinder 8, and the pressure oil in the rodless chamber of the second oil cylinder 8 enters the rodless chamber of the first oil cylinder 7 through the second cartridge valve 6, and the pressure oil in the rod chamber of the first oil cylinder 7 passes through the first slide valve 3 and the second three-position four-way directional control valve 2 and is output to the T port.

[0017] As a preferred embodiment, a cycle oil circuit for low-pressure pumping further includes: there is pressure oil passing through the first pressure oil port Pd and the first control oil port Kz1. The first pilot-operated check valve V1, the second pilot-operated check valve V2, the third pilot-operated check valve V3, and the fourth pilot-operated check valve V4 are all in the reverse conduction state. The fifth pilot-operated check valve V5, the sixth pilot-operated check valve V6, the seventh pilot-operated check valve V7, and the eighth pilot-operated check valve V8 are all in the reverse closed state. The third control oil port Kz3 and the fourth control oil port Kz4 alternately have pressure oil; or there is pressure oil passing through the first pressure oil port Pd and the second control oil port Kz2. The first pilot-operated check valve V1, the second pilot-operated check valve V2, the third pilot-operated check valve V3, and the fourth pilot-operated check valve V4 are all in the reverse conduction state. The fifth pilot-operated check valve V5, the sixth pilot-operated check valve V6, the seventh pilot-operated check valve V7, and the eighth pilot-operated check valve V8 are all in the reverse closed state. The third control oil port Kz3 and the fourth control oil port Kz4 alternately have pressure oil.

[0018] As a preferred embodiment, a cycle oil circuit for high-pressure pumping includes: the pumping high-pressure oil at the input P port sequentially enters the rodless cavity of the first oil cylinder 7 through the first three-position four-way directional control valve 1 and the second slide valve 4. The pressure oil in the rod chamber of the first oil cylinder 7 enters the rod chamber of the second oil cylinder 8 through the first cartridge valve 5. The pressure oil in the rodless cavity of the second oil cylinder 8 passes through the second slide valve 4 and the first three-position four-way directional control valve 1 to be output to the T port; the pumping high-pressure oil at the P port sequentially passes through the first three-position four-way directional control valve 1 and the second slide valve 4 to enter the rodless cavity of the second oil cylinder 8. The pressure oil in the rod chamber of the second oil cylinder 8 enters the rod chamber of the first oil cylinder 7 through the first cartridge valve 5. The pressure oil in the rodless cavity of the first oil cylinder 7 passes through the second slide valve 4 and the first three-position four-way directional control valve 1 to be output to the T port.

[0019] As a preferred embodiment, a cycle oil circuit for high-pressure pumping further includes: there is pressure oil passing through the second pressure oil port Pg and the first control oil port Kz1. The first pilot-operated check valve V1, the second pilot-operated check valve V2, the third pilot-operated check valve V3, and the fourth pilot-operated check valve V4 are all in the reverse closed state. The fifth pilot-operated check valve V5, the sixth pilot-operated check valve V6, the seventh pilot-operated check valve V7, and the eighth pilot-operated check valve V8 are all in the reverse conduction state. The third control oil port Kz3 and the fourth control oil port Kz4 alternately have pressure oil; or there is pressure oil passing through the second pressure oil port Pg and the second control oil port Kz2. The first pilot-operated check valve V1, the second pilot-operated check valve V2, the third pilot-operated check valve V3, and the fourth pilot-operated check valve V4 are all in the reverse closed state. The fifth pilot-operated check valve V5, the sixth pilot-operated check valve V6, the seventh pilot-operated check valve V7, and the eighth pilot-operated check valve V8 are all in the reverse conduction state. The third control oil port Kz3 and the fourth control oil port Kz4 alternately have pressure oil.

[0020] The present invention also provides a control method for a high-low voltage automatic switching control logic system, which is characterized by including: a low-pressure pumping control step; a high-pressure pumping control step.

[0021] As a preferred embodiment, the low-pressure pumping control step specifically includes: when there is pressure oil passing through only the first pressure oil port Pd, the first control oil port Kz1, and the third control oil port Kz3, the first hydraulic control check valve V1, the second hydraulic control check valve V2, the third hydraulic control check valve V3, and the fourth hydraulic control check valve V4 are all in the reverse connection state, and the fifth hydraulic control check valve V5, the sixth hydraulic control check valve V6, the seventh hydraulic control check valve V7, and the eighth hydraulic control check valve V8 are in the reverse closed state. The control oil at the first control oil port Kz1 flows to the second three-position four-way directional control valve 2 through the first hydraulic control check valve V1. The second three-position four-way directional control valve 2 is in the left-position connection. The pressure oil at the third control oil port Kz3 flows to the first spool valve 3 through the second hydraulic control check valve V2. The first spool valve 3 is in the left position. The pumping high-pressure oil input from the P port flows through the second three-position four-way directional control valve 2 and the first spool valve 3 to the rod chamber of the first oil cylinder 7 and the first cartridge valve 5. At this time, there is pressure oil at the control oil port P5 of the first cartridge valve, and the first cartridge valve 5 is closed. The high-pressure oil pushes the piston of the first oil cylinder 7 to move. The pressure oil in the rodless chamber of the first oil cylinder 7 acts on the second cartridge valve 6 and the second spool valve 4. There is no pressure oil at the control oil port P6 of the second cartridge valve, and the second cartridge valve 6 opens. The pressure oil in the rodless chamber of the first oil cylinder 7 enters the rodless chamber of the second oil cylinder 8 through the second cartridge valve 6, pushing the piston to move. The pressure oil in the rod chamber of the second oil cylinder 8 acts on the first cartridge valve 5 and the first spool valve 3. The first cartridge valve 5 is in the closed state. The pressure oil in the rod chamber of the second oil cylinder 8 flows through the first spool valve 3 to the second three-position four-way directional control valve 2 and is output to the T port through the second three-position four-way directional control valve 2; when there is pressure oil at the first pressure oil port Pd, the first control oil port Kz1, and the fourth control oil port Kz4, the pressure oil at the fourth control oil port Kz4 flows to the first spool valve 3 through the third hydraulic control check valve V3. The first spool valve 3 is in the right-position connection. The pumping high-pressure oil input from the P port flows through the second three-position four-way directional control valve 2 and the first spool valve 3 into the rod chamber of the second oil cylinder 8. The high-pressure oil pushes the piston of the second oil cylinder 8 to move. There is no pressure oil at the control oil port P6 of the second cartridge valve, and the second cartridge valve 6 opens. The pressure oil in the rodless chamber of the second oil cylinder 8 acts on the second cartridge valve 6 and enters the rodless chamber of the first oil cylinder 7 through the second cartridge valve 6, pushing the piston of the first oil cylinder 7 to move. The pressure oil in the rod chamber of the first oil cylinder 7 flows through the first spool valve 3 and the second three-position four-way directional control valve 2 to the T port for output; when pressure oil alternately appears at the third control oil port Kz3 and the fourth control oil port Kz4, continuous movement of the first oil cylinder 7 and the second oil cylinder 8 is realized, thereby realizing low-pressure pumping.

[0022] As a preferred embodiment, the high-pressure pumping control steps specifically include: when there is pressure oil passing through only the second pressure oil port Pg, the first control oil port Kz1, and the third control oil port Kz3, the fifth hydraulic check valve V5, the sixth hydraulic check valve V6, the seventh hydraulic check valve V7, and the eighth hydraulic check valve V8 are in the reverse connection state, and the first hydraulic check valve V1, the second hydraulic check valve V2, the third hydraulic check valve V3, and the fourth hydraulic check valve V4 are in the reverse closed state. The pressure oil at the first control oil port Kz1 flows through the fifth hydraulic check valve V5 to the first three-position four-way directional control valve 1, and the pressure oil at the third control oil port Kz3 enters the second spool valve 4 through the sixth hydraulic check valve V6. The left position of the second spool valve 4 is connected, and the high-pressure pumping oil at the input P port flows through the first three-position four-way directional control valve 1 and the second spool valve 4 to the rodless cavity of the first oil cylinder 7 and the second cartridge valve 6. At this time, there is pressure oil at the control oil port P6 of the second cartridge valve, and the second cartridge valve 6 is closed. The high-pressure oil pushes the piston of the first oil cylinder 7 to move, and the pressure oil in the rod chamber of the first oil cylinder 7 flows to the first cartridge valve 5 and the first spool valve 3 and the second three-position four-way directional control valve 2. Since there is no pressure oil at both the first hydraulic check valve V1 and the fourth hydraulic check valve V4, the second three-position four-way directional control valve 2 is in the middle closed state, there is no pressure oil at the control oil port P5 of the first cartridge valve, and the first cartridge valve 5 is in the open state. The pressure oil in the rod chamber of the first oil cylinder 7 flows to the rod chamber of the second oil cylinder 8 to push the piston of the second oil cylinder 8 to move, and the pressure oil in the rodless cavity of the second oil cylinder 8 flows to the second cartridge valve 6 and the second spool valve 4. Since there is pressure oil at the control oil port P6 of the second cartridge valve, the second cartridge valve 6 is closed, and the pressure oil flows through the second spool valve 4 and the first three-position four-way directional control valve 1 to the T port for output; when there is pressure oil at the fourth control oil port Kz4, pressure oil is output to the second spool valve 4 through the seventh hydraulic check valve V7. The right position of the second spool valve 4 is connected, and the high-pressure pumping oil at the input P port flows through the first three-position four-way directional control valve 1 and the second spool valve 4 into the rodless cavity of the second oil cylinder 8 to push the piston of the second oil cylinder 8 to move. The pressure oil in the rod chamber of the second oil cylinder 8 enters the rod chamber of the first oil cylinder 7 through the first cartridge valve 5 to push the piston of the first oil cylinder 7 to move. The pressure oil in the rodless cavity of the first oil cylinder 7 flows through the second spool valve 4 and the first three-position four-way directional control valve 1 to the T port for output; when pressure oil alternately appears at the third control oil port Kz3 and the fourth control oil port Kz4, continuous movement of the first oil cylinder 7 and the second oil cylinder 8 is achieved, thereby realizing high-pressure pumping.

[0023] Advantages achieved by the present invention: First, for a high-low pressure automatic switching control logic device of the present invention, the control logic composed of four groups of pilot-operated check valves, a control oil port assembly, and two cartridge valve control oil ports is internally controlled by a hydraulic valve, reducing the number of solenoid valves and pipeline numbers, being easy to integrate, and saving space. Second, the present invention also proposes a high-low pressure automatic switching control logic system, including a hydraulic system and a high-low pressure automatic switching control logic device. The logic relationship for low-pressure pumping (oil inlet to the small chamber of the cylinder) is as follows: the first pressure oil port Pd, the first control oil port Kz1 or the second control oil port Kz2 is always connected to the pressure oil, the third control oil port Kz3 and the fourth control oil port Kz4 alternately act on the high-pressure oil, and the second pressure oil port Pg does not act on the pressure oil; the logic relationship for high-pressure pumping (oil inlet to the large chamber of the cylinder) is: the second pressure oil port Pg, the first control oil port Kz1 or the second control oil port Kz2 is always connected to the pressure oil, the third control oil port Kz3 and the fourth control oil port Kz4 alternately act on the high-pressure oil, and the first pressure oil port Pd does not act on the pressure oil, thus solving low-pressure pumping and high-pressure pumping as a whole; Third, the present invention also proposes a control method for a high-low pressure automatic switching control logic system. By designing a high-low pressure switching system with a new control logic, the concrete pump can easily achieve the switching from low pressure to high pressure (or from high pressure to low pressure) within a short time, thereby improving the construction efficiency of the concrete pump, reducing the construction intensity of workers, and enhancing the overall performance of the concrete pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structural connection principle of a high-low pressure automatic switching control logic device of the present invention.

[0025] Figure 2 It is a schematic diagram of the oil circuit connection principle of the hydraulic system of the present invention.

[0026] The meanings of the marks in the figure: 1 - first three-position four-way directional control valve, 2 - second three-position four-way directional control valve, 3 - first spool valve, 4 - second spool valve, 5 - first cartridge valve, 6 - second cartridge valve, 7 - first cylinder, 8 - second cylinder, V1 - first pilot-operated check valve, V2 - second pilot-operated check valve, V3 - third pilot-operated check valve, V4 - fourth pilot-operated check valve, V5 - fifth pilot-operated check valve, V6 - sixth pilot-operated check valve, V7 - seventh pilot-operated check valve, V8 - eighth pilot-operated check valve, Kz1 - first control oil port, Kz2 - second control oil port, Kz3 - third control oil port, Kz4 - fourth control oil port, Pd - first pressure oil port, Pg - second pressure oil port, P5 - first cartridge valve control oil port, P6 - second cartridge valve control oil port. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0028] Explanation of related terms: 1) Concrete pump: An energy conversion device that converts hydraulic energy into the pressure energy of flowing concrete. 2) Main cylinder: An energy conversion device that converts hydraulic energy into mechanical energy. The main cylinder is connected to the concrete piston and can convert hydraulic energy into the kinetic energy (potential energy) of concrete. 3) Low-pressure pumping: A state in which the working hydraulic oil enters the rod chamber of the main cylinder to push the main cylinder to work. 4) High-pressure pumping: A state in which the working hydraulic oil enters the rodless chamber of the main cylinder to push the main cylinder to work. 5) Hydraulic control check valve: A control valve that can be reversely fluid-conducted through hydraulic control.

[0029] As Figure 1 shown, the present invention provides a high-low pressure automatic switching control logic device, including a first control logic unit, a second control logic unit, and a control oil port assembly; the first control logic unit is connected to the second control logic unit through the control oil port assembly;

[0030] The control oil port assembly includes a first control oil port Kz1, a second control oil port Kz2, a third control oil port Kz3, and a fourth control oil port Kz4;

[0031] The first control logic unit includes a first pressure oil port Pd, a first hydraulic control check valve V1, a second hydraulic control check valve V2, a third hydraulic control check valve V3, a fourth hydraulic control check valve V4, and a first cartridge valve control oil port P5. The first pressure oil port Pd is respectively connected to the first cartridge valve control oil port P5, the control oil circuit of the first hydraulic control check valve V1, the control oil circuit of the second hydraulic control check valve V2, the control oil circuit of the third hydraulic control check valve V3, and the control oil circuit of the fourth hydraulic control check valve V4;

[0032] The second control logic unit includes a second pressure oil port Pg, a fifth hydraulic control check valve V5, a sixth hydraulic control check valve V6, a seventh hydraulic control check valve V7, an eighth hydraulic control check valve V8, and a second cartridge valve control oil port P6. The second pressure oil port Pg is respectively connected to the second cartridge valve control oil port P6, the control oil circuit of the fifth hydraulic control check valve V5, the control oil circuit of the sixth hydraulic control check valve V6, the control oil circuit of the seventh hydraulic control check valve V7, and the control oil circuit of the eighth hydraulic control check valve V8;

[0033] The first control oil port Kz1 is respectively connected to the oil outlet of the first hydraulic check valve V1 and the oil outlet of the fifth hydraulic check valve V5. The second control oil port Kz2 is respectively connected to the oil outlet of the fourth hydraulic check valve V4 and the oil outlet of the eighth hydraulic check valve V8. The third control oil port Kz3 is respectively connected to the oil outlet of the second hydraulic check valve V2 and the oil outlet of the sixth hydraulic check valve V6. The fourth control oil port Kz4 is respectively connected to the oil outlet of the third hydraulic check valve V3 and the oil outlet of the seventh hydraulic check valve V7.

[0034] The present invention further provides a high-low pressure automatic switching control logic system, including a hydraulic system and a high-low pressure automatic switching control logic device. The oil ports of the hydraulic system are respectively connected to a first control logic unit and a second control logic unit.

[0035] As Figure 2 shown, as a preferred embodiment, the hydraulic system includes a first three-position four-way directional control valve 1, a second three-position four-way directional control valve 2, a first spool valve 3, a second spool valve 4, a first cartridge valve 5, a second cartridge valve 6, a first oil cylinder 7, and a second oil cylinder 8. The first cartridge valve 5 is respectively connected to the rod chamber of the first oil cylinder 7, the rod chamber of the second oil cylinder 8, and the first spool valve 3. The first spool valve 3 is connected to the second three-position four-way directional control valve 2. The second cartridge valve 6 is respectively connected to the rodless chamber of the first oil cylinder 7, the rodless chamber of the second oil cylinder 8, and the second spool valve 4. The second spool valve 4 is connected to the first three-position four-way directional control valve 1. The first three-position four-way directional control valve 1 and the second three-position four-way directional control valve 2 are externally connected to the pumped high-pressure oil through the P port.

[0036] As a preferred embodiment, the first three-position four-way directional control valve 1 is respectively connected to the inlet oil port of the fifth hydraulic check valve V5 and the inlet oil port of the eighth hydraulic check valve V8. The second three-position four-way directional control valve 2 is respectively connected to the inlet oil port of the first hydraulic check valve V1 and the inlet oil port of the fourth hydraulic check valve V4. The first spool valve 3 is respectively connected to the inlet oil port of the second hydraulic check valve V2 and the inlet oil port of the third hydraulic check valve V3. The second spool valve 4 is respectively connected to the inlet oil port of the sixth hydraulic check valve V6 and the inlet oil port of the seventh hydraulic check valve V7.

[0037] As a preferred embodiment, the first cartridge valve 5 is connected to the first pressure oil port Pd through the first cartridge valve control oil port P5. The second cartridge valve 6 is connected to the second pressure oil port Pg through the second cartridge valve control oil port P6.

[0038] As a preferred embodiment, a circulating oil circuit for low-pressure pumping includes: the high-pressure pumping oil input at port P sequentially passes through the second three-position four-way directional control valve 2 and the first slide valve 3 and enters the rod chamber of the first oil cylinder 7. The pressure oil in the rodless chamber of the first oil cylinder 7 passes through the second cartridge valve 6 and enters the rodless chamber of the second oil cylinder 8. The pressure oil in the rod chamber of the second oil cylinder 8 passes through the first slide valve 3 and the second three-position four-way directional control valve 2 and is output to port T; the high-pressure pumping oil at port P sequentially passes through the second three-position four-way directional control valve 2 and the first slide valve 3 and enters the rod chamber of the second oil cylinder 8. The pressure oil in the rodless chamber of the second oil cylinder 8 passes through the second cartridge valve 6 and enters the rodless chamber of the first oil cylinder 7. The pressure oil in the rod chamber of the first oil cylinder 7 passes through the first slide valve 3 and the second three-position four-way directional control valve 2 and is output to port T.

[0039] As a preferred embodiment, a circulating oil circuit for low-pressure pumping further includes: there is pressure oil passing through the first pressure oil port Pd and the first control oil port Kz1. The first hydraulic check valve V1, the second hydraulic check valve V2, the third hydraulic check valve V3, and the fourth hydraulic check valve V4 are all in the reverse connection state. The fifth hydraulic check valve V5, the sixth hydraulic check valve V6, the seventh hydraulic check valve V7, and the eighth hydraulic check valve V8 are all in the reverse closed state. The third control oil port Kz3 and the fourth control oil port Kz4 alternately have pressure oil; or there is pressure oil passing through the first pressure oil port Pd and the second control oil port Kz2. The first hydraulic check valve V1, the second hydraulic check valve V2, the third hydraulic check valve V3, and the fourth hydraulic check valve V4 are all in the reverse connection state. The fifth hydraulic check valve V5, the sixth hydraulic check valve V6, the seventh hydraulic check valve V7, and the eighth hydraulic check valve V8 are all in the reverse closed state. The third control oil port Kz3 and the fourth control oil port Kz4 alternately have pressure oil.

[0040] As a preferred embodiment, a circulating oil circuit for high-pressure pumping includes: the high-pressure pumping oil input at port P sequentially passes through the first three-position four-way directional control valve 1 and the second slide valve 4 and enters the rodless chamber of the first oil cylinder 7. The pressure oil in the rod chamber of the first oil cylinder 7 passes through the first cartridge valve 5 and enters the rod chamber of the second oil cylinder 8. The pressure oil in the rodless chamber of the second oil cylinder 8 passes through the second slide valve 4 and the first three-position four-way directional control valve 1 and is output to port T; the high-pressure pumping oil at port P sequentially passes through the first three-position four-way directional control valve 1 and the second slide valve 4 and enters the rodless chamber of the second oil cylinder 8. The pressure oil in the rod chamber of the second oil cylinder 8 passes through the first cartridge valve 5 and enters the rodless chamber of the first oil cylinder 7. The pressure oil in the rodless chamber of the first oil cylinder 7 passes through the second slide valve 4 and the first three-position four-way directional control valve 1 and is output to port T.

[0041] As a preferred embodiment, a circulating oil circuit of the high-pressure pump also includes: the second pressure oil port Pg and the first control oil port Kz1 have pressure oil passing through, the first hydraulically controlled one-way valve V1, the second hydraulically controlled one-way valve V2, the third hydraulically controlled one-way valve V3, and the fourth hydraulically controlled one-way valve V4 are all in a reverse closed state, the fifth hydraulically controlled one-way valve V5, the sixth hydraulically controlled one-way valve V6, the seventh hydraulically controlled one-way valve V7, and the eighth hydraulically controlled one-way valve V8 are all in a reverse connected state, the third control oil port Kz3, the fourth control oil port Kz4, the second hydraulically controlled one-way valve V2, the third hydraulically controlled one-way valve V3, and the fourth hydraulically controlled one-way valve V4 are all in a reverse closed state, or pressure oil passes through the second pressure oil port Pg and the second control oil port Kz2, the first hydraulically controlled one-way valve V1, the second hydraulically controlled one-way valve V2, the third hydraulically controlled one-way valve V3 and the fourth hydraulically controlled one-way valve V4 are all in a reverse closed state, the fifth hydraulically controlled one-way valve V5, the sixth hydraulically controlled one-way valve V6, the seventh hydraulically controlled one-way valve V7 and the eighth hydraulically controlled one-way valve V8 are all in a reverse connected state, and pressure oil appears alternately in the third control oil port Kz3 and the fourth control oil port Kz4.

[0042] Under the action of the first pressure oil port Pd and the second pressure oil port Pg, the hydraulically controlled one-way valves V1 to V8 are all in the reverse connection state. If no pressure oil passes through the first control oil port Kz1, the second control oil port Kz2, the third control oil port Kz3 and the fourth control oil port Kz4, no control oil flows to p11, p12, p21, p22, p31, p32, p41 and p42, the first three-position four-way directional valve 1 and the second three-position four-way directional valve 2 are in the middle position, the pumped high-pressure oil is on standby at the P port, and the system is in a non-pumping state.

[0043] Low-pressure pumping process, specifically including: when there is pressure oil passing through only the first pressure oil port Pd, the first control oil port Kz1, and the third control oil port Kz3, the first hydraulic check valve V1, the second hydraulic check valve V2, the third hydraulic check valve V3, and the fourth hydraulic check valve V4 are all in the reverse connection state, and the fifth hydraulic check valve V5, the sixth hydraulic check valve V6, the seventh hydraulic check valve V7, and the eighth hydraulic check valve V8 are in the reverse closed state. The control oil at the first control oil port Kz1 flows through the first hydraulic check valve V1 to the second three-position four-way directional control valve 2. The second three-position four-way directional control valve 2 is in the left position connection. The pressure oil at the third control oil port Kz3 flows through the second hydraulic check valve V2 to the first spool valve 3. The first spool valve 3 is in the left position. The pumped high-pressure oil input from the P port flows through the second three-position four-way directional control valve 2 and the first spool valve 3 to the rodless cavity of the first oil cylinder 7 and the first cartridge valve 5. At this time, there is pressure oil at the control oil port P5 of the first cartridge valve, and the first cartridge valve 5 is closed. The high-pressure oil pushes the piston of the first oil cylinder 7 to move. The pressure oil in the rodless cavity of the first oil cylinder 7 acts on the second cartridge valve 6 and the second spool valve 4. There is no pressure oil at the control oil port P6 of the second cartridge valve, and the second cartridge valve 6 is opened. The pressure oil in the rodless cavity of the first oil cylinder 7 enters the rodless cavity of the second oil cylinder 8 through the second cartridge valve 6, pushing the piston to move. The pressure oil in the rodless cavity of the second oil cylinder 8 acts on the first cartridge valve 5 and the first spool valve 3. The first cartridge valve 5 is in the closed state. The pressure oil in the rodless cavity of the second oil cylinder 8 flows through the first spool valve 3 to the second three-position four-way directional control valve 2 and is output to the T port through the second three-position four-way directional control valve 2; when there is pressure oil at the first pressure oil port Pd, the first control oil port Kz1, and the fourth control oil port Kz4, the pressure oil at the fourth control oil port Kz4 flows through the third hydraulic check valve V3 to the first spool valve 3. The first spool valve 3 is in the right position connection. The pumped high-pressure oil input from the P port flows through the second three-position four-way directional control valve 2 and the first spool valve 3 into the rodless cavity of the second oil cylinder 8. The high-pressure oil pushes the piston of the second oil cylinder 8 to move. There is no pressure oil at the control oil port P6 of the second cartridge valve, and the second cartridge valve 6 is opened. The pressure oil in the rodless cavity of the second oil cylinder 8 acts on the second cartridge valve 6 and enters the rodless cavity of the first oil cylinder 7 through the second cartridge valve 6, pushing the piston of the first oil cylinder 7 to move. The pressure oil in the rodless cavity of the first oil cylinder 7 flows through the first spool valve 3 and the second three-position four-way directional control valve 2 to the T port for output; when pressure oil alternately appears at the third control oil port Kz3 and the fourth control oil port Kz4, continuous movement of the first oil cylinder 7 and the second oil cylinder 8 is achieved, thereby realizing low-pressure pumping.

[0044] As a preferred embodiment, the high-pressure pumping control steps specifically include: when there is pressure oil passing through only the second pressure oil port Pg, the first control oil port Kz1, and the third control oil port Kz3, the fifth hydraulic check valve V5, the sixth hydraulic check valve V6, the seventh hydraulic check valve V7, and the eighth hydraulic check valve V8 are in the reverse connection state, and the first hydraulic check valve V1, the second hydraulic check valve V2, the third hydraulic check valve V3, and the fourth hydraulic check valve V4 are in the reverse closed state. The pressure oil at the first control oil port Kz1 flows through the fifth hydraulic check valve V5 to the first three-position four-way directional control valve 1, and the pressure oil at the third control oil port Kz3 enters the second spool valve 4 through the sixth hydraulic check valve V6. The left position of the second spool valve 4 is connected, and the high-pressure pumping oil at the input P port flows through the first three-position four-way directional control valve 1 and the second spool valve 4 to the rodless cavity of the first hydraulic cylinder 7 and the second cartridge valve 6. At this time, there is pressure oil at the control oil port P6 of the second cartridge valve, and the second cartridge valve 6 is closed. The high-pressure oil pushes the piston of the first hydraulic cylinder 7 to move, and the pressure oil in the rod chamber of the first hydraulic cylinder 7 flows to the first cartridge valve 5 and the first spool valve 3 and the second three-position four-way directional control valve 2. Since there is no pressure oil at both the first hydraulic check valve V1 and the fourth hydraulic check valve V4, the second three-position four-way directional control valve 2 is in the middle closed state, there is no pressure oil at the control oil port P5 of the first cartridge valve, and the first cartridge valve 5 is in the open state. The pressure oil in the rod chamber of the first hydraulic cylinder 7 flows to the rod chamber of the second hydraulic cylinder 8 to push the piston of the second hydraulic cylinder 8 to move, and the pressure oil in the rodless cavity of the second hydraulic cylinder 8 flows to the second cartridge valve 6 and the second spool valve 4. Since there is pressure oil at the control oil port P6 of the second cartridge valve, the second cartridge valve 6 is closed, and the pressure oil flows through the second spool valve 4 and the first three-position four-way directional control valve 1 to the T port for output; when there is pressure oil at the fourth control oil port Kz4, pressure oil is output to the second spool valve 4 through the seventh hydraulic check valve V7. The right position of the second spool valve 4 is connected, and the high-pressure pumping oil at the input P port flows through the first three-position four-way directional control valve 1 and the second spool valve 4 into the rodless cavity of the second hydraulic cylinder 8 to push the piston of the second hydraulic cylinder 8 to move. The pressure oil in the rod chamber of the second hydraulic cylinder 8 enters the rod chamber of the first hydraulic cylinder 7 through the first cartridge valve 5 to push the piston of the first hydraulic cylinder 7 to move. The pressure oil in the rodless cavity of the first hydraulic cylinder 7 flows through the second spool valve 4 and the first three-position four-way directional control valve 1 to the T port for output; when pressure oil alternately appears at the third control oil port Kz3 and the fourth control oil port Kz4, continuous movement of the first hydraulic cylinder 7 and the second hydraulic cylinder 8 is achieved, and thus high-pressure pumping is realized.

[0045] The core of the present invention lies in: 1. The core part of this hydraulic system is composed of four slide valves (i.e., the first three-position four-way directional control valve 1, the second three-position four-way directional control valve 2, the first slide valve 3, and the second slide valve 4), four groups of pilot-operated check valves (the first pilot-operated check valve V1, the second pilot-operated check valve V2, the third pilot-operated check valve V3, the fourth pilot-operated check valve V4, the fifth pilot-operated check valve V5, the sixth pilot-operated check valve V6, the seventh pilot-operated check valve V7, and the eighth pilot-operated check valve V8), and two cartridge valves (the first cartridge valve 5 and the second cartridge valve 6). 2. The arrangement mode of the spools of the four slide valves: (1) The spools of the four slide valves (i.e., the first three-position four-way directional control valve 1, the second three-position four-way directional control valve 2, the first slide valve 3, and the second slide valve 4) are arranged flat, and are distributed at both ends of the control mechanism (i.e., the four groups of pilot-operated check valves); (2) The spools of the four slide valves (i.e., the first three-position four-way directional control valve 1, the second three-position four-way directional control valve 2, the first slide valve 3, and the second slide valve 4) are arranged in two layers, front and back, and are arranged at one end of the control mechanism (i.e., the four groups of pilot-operated check valves); 3. Working logic (according to Figure 1 and Figure 2 symbols): The logic relationship of low-pressure pumping (oil inlet to the small chamber of the cylinder) is as follows: The first pressure oil port Pd, the first control oil port Kz1 or the second control oil port Kz2 is always connected to the pressure oil, the third control oil port Kz3 and the fourth control oil port Kz4 alternately act on the high-pressure oil, and the second pressure oil port Pg does not act on the pressure oil; The logic relationship of high-pressure pumping (oil inlet to the large chamber of the cylinder) is: The second pressure oil port Pg, the first control oil port Kz1 or the second control oil port Kz2 is always connected to the pressure oil, the third control oil port Kz3 and the fourth control oil port Kz4 alternately act on the high-pressure oil, and the first pressure oil port Pd does not act on the pressure oil.

[0046] The above is only the preferred implementation mode of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and deformations can still be made, and these improvements and deformations should also be regarded as the protection scope of the present invention.

Claims

1. A high-low pressure automatic switching control logic device, characterized in that, it includes a first control logic unit, a second control logic unit, and a control oil port assembly; the first control logic unit is connected to the second control logic unit through the control oil port assembly; the control oil port assembly includes a first control oil port (Kz1), a second control oil port (Kz2), a third control oil port (Kz3), and a fourth control oil port (Kz4); the first control logic unit includes a first pressure oil port (Pd), a first pilot-operated check valve (V1), a second pilot-operated check valve (V2), a third pilot-operated check valve (V3), a fourth pilot-operated check valve (V4), and a first cartridge valve control oil port (P5), and the first pressure oil port (Pd) is respectively connected to the first cartridge valve control oil port (P5), the control oil circuit of the first pilot-operated check valve (V1), the control oil circuit of the second pilot-operated check valve (V2), the control oil circuit of the third pilot-operated check valve (V3), and the control oil circuit of the fourth pilot-operated check valve (V4); the second control logic unit includes a second pressure oil port (Pg), a fifth pilot-operated check valve (V5), a sixth pilot-operated check valve (V6), a seventh pilot-operated check valve (V7), an eighth pilot-operated check valve (V8), and a second cartridge valve control oil port (P6), and the second pressure oil port (Pg) is respectively connected to the second cartridge valve control oil port (P6), the control oil circuit of the fifth pilot-operated check valve (V5), the control oil circuit of the sixth pilot-operated check valve (V6), the control oil circuit of the seventh pilot-operated check valve (V7), and the control oil circuit of the eighth pilot-operated check valve (V8); the first control oil port (Kz1) is respectively connected to the oil outlet of the first pilot-operated check valve (V1) and the oil outlet of the fifth pilot-operated check valve (V5), the second control oil port (Kz2) is respectively connected to the oil outlet of the fourth pilot-operated check valve (V4) and the oil outlet of the eighth pilot-operated check valve (V8), the third control oil port (Kz3) is respectively connected to the oil outlet of the second pilot-operated check valve (V2) and the oil outlet of the sixth pilot-operated check valve (V6), and the fourth control oil port (Kz4) is respectively connected to the oil outlet of the third pilot-operated check valve (V3) and the oil outlet of the seventh pilot-operated check valve (V7).

2. A high-low pressure automatic switching control logic system, characterized in that, Comprising a hydraulic system and the high-low pressure automatic switching control logic device according to claim 1, the oil ports of the hydraulic system are respectively connected to the first control logic unit and the second control logic unit; the hydraulic system includes a first three-position four-way directional control valve (1), a second three-position four-way directional control valve (2), a first slide valve (3), a second slide valve (4), a first cartridge valve (5), a second cartridge valve (6), a first oil cylinder (7), and a second oil cylinder (8), wherein the first three-position four-way directional control valve (1), the second three-position four-way directional control valve (2), the first slide valve (3), and the second slide valve (4) are all slide valves; the first cartridge valve (5) is respectively connected to the rod chamber of the first oil cylinder (7), the rod chamber of the second oil cylinder (8), and the first slide valve (3), and the first slide valve (3) is connected to the second three-position four-way directional control valve (2); the second cartridge valve (6) is respectively connected to the rodless chamber of the first oil cylinder (7), the rodless chamber of the second oil cylinder (8), and the second slide valve (4), and the second slide valve (4) is connected to the first three-position four-way directional control valve (1); the first three-position four-way directional control valve (1) and the second three-position four-way directional control valve (2) are externally connected to the pumped high-pressure oil through the P port; the valve cores of the first three-position four-way directional control valve (1), the second three-position four-way directional control valve (2), the first slide valve (3), and the second slide valve (4) are arranged in a flat layout, and the first hydraulic control check valve (V1), the second hydraulic control check valve (V2), the third hydraulic control check valve (V3), the fourth hydraulic control check valve (V4), the fifth hydraulic control check valve (V5), the sixth hydraulic control check valve (V6), the seventh hydraulic control check valve (V7), and the eighth hydraulic control check valve (V8) form four groups of hydraulic control check valves and are distributed at both ends; or the valve cores of the first three-position four-way directional control valve (1), the second three-position four-way directional control valve (2), the first slide valve (3), and the second slide valve (4) are arranged in two layers, front and back, and the first hydraulic control check valve (V1), the second hydraulic control check valve (V2), the third hydraulic control check valve (V3), the fourth hydraulic control check valve (V4), the fifth hydraulic control check valve (V5), the sixth hydraulic control check valve (V6), the seventh hydraulic control check valve (V7), and the eighth hydraulic control check valve (V8) form four groups of hydraulic control check valves and are arranged at one end.

3. The high-low pressure automatic switching control logic system according to claim 2, characterized in that The first three-position four-way directional control valve (1) is respectively connected to the oil inlet of the fifth pilot-operated check valve (V5) and the oil inlet of the eighth pilot-operated check valve (V8); the second three-position four-way directional control valve (2) is respectively connected to the oil inlet of the first pilot-operated check valve (V1) and the oil inlet of the fourth pilot-operated check valve (V4); the first spool valve (3) is respectively connected to the oil inlet of the second pilot-operated check valve (V2) and the oil inlet of the third pilot-operated check valve (V3); the second spool valve (4) is respectively connected to the oil inlet of the sixth pilot-operated check valve (V6) and the oil inlet of the seventh pilot-operated check valve (V7); the first cartridge valve (5) is connected to the first pressure oil port (Pd) through the control oil port (P5) of the first cartridge valve; the second cartridge valve (6) is connected to the second pressure oil port (Pg) through the control oil port (P6) of the second cartridge valve.

4. A high-low pressure automatic switching control logic system according to claim 3, characterized in that A circulating oil circuit for low-pressure pumping includes: the high-pressure pumping oil input from the P port sequentially enters the rod chamber of the first oil cylinder (7) through the second three-position four-way directional control valve (2) and the first spool valve (3), and the pressure oil in the rodless chamber of the first oil cylinder (7) enters the rodless chamber of the second oil cylinder (8) through the second cartridge valve (6), and the pressure oil in the rod chamber of the second oil cylinder (8) passes through the first spool valve (3) and the second three-position four-way directional control valve (2) and is output to the T port; the high-pressure pumping oil located at the P port sequentially passes through the second three-position four-way directional control valve (2) and the first spool valve (3) and enters the rod chamber of the second oil cylinder (8), and the pressure oil in the rodless chamber of the second oil cylinder (8) enters the rodless chamber of the first oil cylinder (7) through the second cartridge valve (6), and the pressure oil in the rod chamber of the first oil cylinder (7) passes through the first spool valve (3) and the second three-position four-way directional control valve (2) and is output to the T port.

5. A high-low pressure automatic switching control logic system according to claim 4, characterized in that One cycle oil circuit of the low-pressure pumping further includes: there is pressure oil passing through the first pressure oil port (Pd) and the first control oil port (Kz1), the first pilot-operated check valve (V1), the second pilot-operated check valve (V2), the third pilot-operated check valve (V3), and the fourth pilot-operated check valve (V4) are all in the reverse connection state, the fifth pilot-operated check valve (V5), the sixth pilot-operated check valve (V6), the seventh pilot-operated check valve (V7), and the eighth pilot-operated check valve (V8) are all in the reverse closed state, and pressure oil alternately appears at the third control oil port (Kz3) and the fourth control oil port (Kz4); or there is pressure oil passing through the first pressure oil port (Pd) and the second control oil port (Kz2), the first pilot-operated check valve (V1), the second pilot-operated check valve (V2), the third pilot-operated check valve (V3), and the fourth pilot-operated check valve (V4) are all in the reverse connection state, the fifth pilot-operated check valve (V5), the sixth pilot-operated check valve (V6), the seventh pilot-operated check valve (V7), and the eighth pilot-operated check valve (V8) are all in the reverse closed state, and pressure oil alternately appears at the third control oil port (Kz3) and the fourth control oil port (Kz4).

6. A high-low pressure automatic switching control logic system according to claim 3, characterized in that One cycle oil circuit of the high-pressure pumping includes: the high-pressure pumping oil input at port P sequentially enters the rodless cavity of the first oil cylinder (7) through the first three-position four-way directional control valve (1) and the second slide valve (4), the pressure oil in the rod cavity of the first oil cylinder (7) enters the rod cavity of the second oil cylinder (8) through the first cartridge valve (5), and the pressure oil in the rodless cavity of the second oil cylinder (8) passes through the second slide valve (4) and the first three-position four-way directional control valve (1) and is output to port T; the high-pressure pumping oil located at port P sequentially enters the rodless cavity of the second oil cylinder (8) through the first three-position four-way directional control valve (1) and the second slide valve (4), the pressure oil in the rod cavity of the second oil cylinder (8) enters the rod cavity of the first oil cylinder (7) through the first cartridge valve (5), and the pressure oil in the rodless cavity of the first oil cylinder (7) passes through the second slide valve (4) and the first three-position four-way directional control valve (1) and is output to port T.

7. A high-low pressure automatic switching control logic system according to claim 6, characterized in that One cycle oil circuit of the high-pressure pumping further includes: there is pressure oil passing through the second pressure oil port (Pg) and the first control oil port (Kz1), the first pilot-operated check valve (V1), the second pilot-operated check valve (V2), the third pilot-operated check valve (V3), and the fourth pilot-operated check valve (V4) are all in the reverse closed state, the fifth pilot-operated check valve (V5), the sixth pilot-operated check valve (V6), the seventh pilot-operated check valve (V7), and the eighth pilot-operated check valve (V8) are all in the reverse open state, and pressure oil alternately appears at the third control oil port (Kz3) and the fourth control oil port (Kz4); or there is pressure oil passing through the second pressure oil port (Pg) and the second control oil port (Kz2), the first pilot-operated check valve (V1), the second pilot-operated check valve (V2), the third pilot-operated check valve (V3), and the fourth pilot-operated check valve (V4) are all in the reverse closed state, the fifth pilot-operated check valve (V5), the sixth pilot-operated check valve (V6), the seventh pilot-operated check valve (V7), and the eighth pilot-operated check valve (V8) are all in the reverse open state, and pressure oil alternately appears at the third control oil port (Kz3) and the fourth control oil port (Kz4).

8. A control method for a high-low pressure automatic switching control logic system according to claim 2 Characterized in that It includes Low-pressure pumping control steps High-pressure pumping control steps 9. A control method for a high-low pressure automatic switching control logic system according to claim 8 Characterized in that The low-pressure pumping control steps specifically include: when there is pressure oil passing through only the first pressure oil port (Pd), the first control oil port (Kz1), and the third control oil port (Kz3), the first hydraulic check valve (V1), the second hydraulic check valve (V2), the third hydraulic check valve (V3), and the fourth hydraulic check valve (V4) are all in the reverse connection state, and the fifth hydraulic check valve (V5), the sixth hydraulic check valve (V6), the seventh hydraulic check valve (V7), and the eighth hydraulic check valve (V8) are in the reverse closed state. The control oil at the first control oil port (Kz1) flows through the first hydraulic check valve (V1) to the left position of the second three-position four-way directional control valve (2). The pressure oil at the third control oil port (Kz3) flows through the second hydraulic check valve (V2) to the left position of the first spool valve (3). The high-pressure pumping oil input from the P port flows through the second three-position four-way directional control valve (2) and the first spool valve (3) to the rod chamber of the first oil cylinder (7) and the first cartridge valve (5). At this time, there is pressure oil at the control oil port (P5) of the first cartridge valve, and the first cartridge valve (5) is closed. The high-pressure oil pushes the piston of the first oil cylinder (7) to move. The pressure oil in the rodless chamber of the first oil cylinder (7) acts on the second cartridge valve (6) and the second spool valve (4). There is no pressure oil at the control oil port (P6) of the second cartridge valve, and the second cartridge valve (6) is opened. The pressure oil in the rodless chamber of the first oil cylinder (7) enters the rodless chamber of the second oil cylinder (8) through the second cartridge valve (6) to push the piston to move. The pressure oil in the rod chamber of the second oil cylinder (8) acts on the first cartridge valve (5) and the first spool valve (3). The first cartridge valve (5) is in the closed state. The pressure oil in the rod chamber of the second oil cylinder (8) flows through the first spool valve (3) to the second three-position four-way directional control valve (2) and is output to the T port through the second three-position four-way directional control valve (2); when there is pressure oil at the first pressure oil port (Pd), the first control oil port (Kz1), and the fourth control oil port (Kz4), the pressure oil at the fourth control oil port (Kz4) flows through the third hydraulic check valve (V3) to the right position of the first spool valve (3). The high-pressure pumping oil input from the P port flows through the second three-position four-way directional control valve (2) and the first spool valve (3) into the rod chamber of the second oil cylinder (8). The high-pressure oil pushes the piston of the second oil cylinder (8) to move. There is no pressure oil at the control oil port (P6) of the second cartridge valve, and the second cartridge valve (6) is opened. The pressure oil in the rodless chamber of the second oil cylinder (8) acts on the second cartridge valve (6) and enters the rodless chamber of the first oil cylinder (7) through the second cartridge valve (6) to push the piston of the first oil cylinder (7) to move. The pressure oil in the rod chamber of the first oil cylinder (7) flows through the first spool valve (3) and the second three-position four-way directional control valve (2) to the T port for output; when pressure oil alternately appears at the third control oil port (Kz3) and the fourth control oil port (Kz4), continuous movement of the first oil cylinder (7) and the second oil cylinder (8) is achieved, thereby realizing low-pressure pumping.

10. The control method of a high-low pressure automatic switching control logic system according to claim 8, characterized in that The high-pressure pumping control steps specifically include: when there is pressure oil passing through only the second pressure oil port (Pg), the first control oil port (Kz1), and the third control oil port (Kz3), the fifth hydraulic check valve (V5), the sixth hydraulic check valve (V6), the seventh hydraulic check valve (V7), and the eighth hydraulic check valve (V8) are in the reverse connection state, and the first hydraulic check valve (V1), the second hydraulic check valve (V2), the third hydraulic check valve (V3), and the fourth hydraulic check valve (V4) are in the reverse closed state. The pressure oil at the first control oil port (Kz1) flows to the first three-position four-way directional control valve (1) through the fifth hydraulic check valve (V5). The pressure oil at the third control oil port (Kz3) enters the left position of the second spool valve (4) through the sixth hydraulic check valve (V6). The high-pressure pumping oil input at the P port flows through the first three-position four-way directional control valve (1) and the second spool valve (4) to the rodless cavity of the first hydraulic cylinder (7) and the second cartridge valve (6). At this time, there is pressure oil at the control oil port (P6) of the second cartridge valve, and the second cartridge valve (6) is closed. The high-pressure oil pushes the piston of the first hydraulic cylinder (7) to move. The pressure oil in the rod chamber of the first hydraulic cylinder (7) flows to the first cartridge valve (5) and the first spool valve (3) and the second three-position four-way directional control valve (2). Since there is no pressure oil at both the first hydraulic check valve (V1) and the fourth hydraulic check valve (V4), the second three-position four-way directional control valve (2) is in the middle closed state, and there is no pressure oil at the control oil port (P5) of the first cartridge valve. The first cartridge valve (5) is in the open state. The pressure oil in the rod chamber of the first hydraulic cylinder (7) flows to the rod chamber of the second hydraulic cylinder (8) to push the piston of the second hydraulic cylinder (8) to move. The pressure oil in the rodless cavity of the second hydraulic cylinder (8) flows to the second cartridge valve (6) and the second spool valve (4). Since there is pressure oil at the control oil port (P6) of the second cartridge valve, the second cartridge valve (6) is closed, and the pressure oil flows through the second spool valve (4) and the first three-position four-way directional control valve (1) to the T port for output; when there is pressure oil at the fourth control oil port (Kz4), the pressure oil is output to the right position of the second spool valve (4) through the seventh hydraulic check valve (V7). The high-pressure pumping oil input at the P port flows through the first three-position four-way directional control valve (1) and the second spool valve (4) into the rodless cavity of the second hydraulic cylinder (8) to push the piston of the second hydraulic cylinder (8) to move. The pressure oil in the rod chamber of the second hydraulic cylinder (8) passes through the first cartridge valve (5) into the rod chamber of the first hydraulic cylinder (7) to push the piston of the first hydraulic cylinder (7) to move. The pressure oil in the rodless cavity of the first hydraulic cylinder (7) passes through the second spool valve (4) and the first three-position four-way directional control valve (1) to the T port for output; when pressure oil alternately appears at the third control oil port (Kz3) and the fourth control oil port (Kz4), continuous movement of the first hydraulic cylinder (7) and the second hydraulic cylinder (8) is achieved, thereby realizing high-pressure pumping.

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