Hydraulic system for the travel of a construction machine and method of operation thereof

Abstract

The application discloses an engineering machinery walking hydraulic system and a working method thereof in the technical field of engineering machinery, and aims to solve the problem that the original double walking pedal needs to be used to correct the direction, which influences the coherence and convenience of the straight-line walking of the excavator. The engineering machinery walking hydraulic system comprises a first pump, a second pump, a first control valve, a second control valve and a third control valve. The input ends of the first pump and the second pump are connected with an oil tank. The output end of the first pump is connected with the first end of the third control valve and the first end of the first control valve. The application can realize the straight-line walking function by only adding the shuttle valve group and the switching valve without increasing the number of pilot pressure sensors or moving the position of the pilot pressure sensor. The excavator can be turned and the direction can be corrected without interrupting the walking, the coherence and convenience of the straight-line walking of the excavator are ensured, and the operation comfort of the driver is improved.

Description

Technical Field

[0001] This invention relates to a hydraulic system for the movement of engineering machinery and its working method, belonging to the field of engineering machinery technology. Background Technology

[0002] The walking function of hydraulically controlled tracked excavators is controlled by two walking pedals: the left pedal controls the left travel motor, and the right pedal controls the right travel motor. Simultaneous pedal presses in the same direction achieve straight-line movement. Different pedal strokes allow for turning during movement; pressing the pedals forward and backward with each foot allows for turning on the spot. In excavator walking control, to improve operator convenience, the straight-line walking control function is simplified, typically by adding a single-foot pedal. Single-foot control for straight-line movement cannot be used for turning; the operator must re-use the original dual-foot pedals. Because actual working surfaces differ from ideal surfaces, the excavator often veers left or right during straight-line movement, requiring the operator to re-use the dual-foot pedals for correction. During long-distance travel, turning and directional correction require the operator's feet to move between the single-foot and dual-foot pedals, and switching pedals interrupts the excavator's movement, reducing the continuity of movement and operator comfort.

[0003] In summary, existing hydraulic travel systems typically add a single foot pedal to control the excavator's straight-line movement. This pedal lacks steering functionality, requiring the operator to revert to using the original dual-foot pedals for steering and directional corrections. This impacts the continuity and convenience of the excavator's straight-line movement, as well as the operator's comfort. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a hydraulic system for the movement of engineering machinery and its working method. By cooperating with a switching valve and a shuttle valve assembly, in excavator systems without single-foot pedal linear movement or handle-controlled linear movement functions, linear movement can be achieved simply by adding a shuttle valve assembly and a switching valve without increasing the number of pilot pressure sensors or moving their positions. Furthermore, during the excavator's movement, this invention can turn and correct the direction of the excavator without stopping the movement, ensuring the continuity and convenience of the excavator's linear movement and improving the operator's comfort.

[0005] To solve the above-mentioned technical problems, the present invention is implemented using the following technical solution:

[0006] In a first aspect, the present invention provides a hydraulic system for the movement of engineering machinery, comprising a first pump, a second pump, a first control valve, a second control valve, and a third control valve;

[0007] The input ends of the first pump and the second pump are both connected to the oil tank; the output end of the first pump is simultaneously connected to the first end of the third control valve and the first end of the first control valve; the second and third ends of the first control valve are both connected to the oil cylinder; the second and third ends of the third control valve are both connected to the first motor; the output end of the second pump is connected to the first end of the second control valve; the second and third ends of the second control valve are both connected to the second motor; and the fourth ends of the first control valve, the second control valve, and the third control valve are all connected to the oil tank.

[0008] The control ports of the second control valve and the third control valve are both connected to the shuttle valve assembly. The control port of the first control valve and the shuttle valve assembly are both connected to the switching valve. The shuttle valve assembly is connected to the travel pilot valve. The switching valve is connected to the handle. The travel pilot valve and the handle are both connected to the gear pump. The gear pump is connected to the oil tank.

[0009] Furthermore, the switching valve and the handle are connected via a safety shut-off valve assembly and a pressure measuring block.

[0010] Furthermore, the first, second, third, and fourth ports of the shuttle valve assembly are all connected to the travel pilot valve, and the ninth and tenth ports of the shuttle valve assembly are all connected to the switching valve.

[0011] The control port of the third control valve includes a first control terminal and a second control terminal. The first control terminal is connected to the fifth port of the shuttle valve assembly, and the second control terminal is connected to the sixth port of the shuttle valve assembly.

[0012] The control ports of the second control valve include a third control terminal and a fourth control terminal. The third control terminal is connected to the seventh port of the shuttle valve assembly, and the fourth control terminal is connected to the eighth port of the shuttle valve assembly.

[0013] Furthermore, the first port of the travel pilot valve is connected to the gear pump, the second port of the travel pilot valve is connected to the oil tank, the third port of the travel pilot valve is connected to the first port of the shuttle valve assembly, the fourth port of the travel pilot valve is connected to the second port of the shuttle valve assembly, the fifth port of the travel pilot valve is connected to the third port of the shuttle valve assembly, and the sixth port of the travel pilot valve is connected to the fourth port of the shuttle valve assembly.

[0014] Furthermore, a first pressure sensor and a second pressure sensor are connected to the travel pilot valve; a third pressure sensor and a fourth pressure sensor are connected to the pressure measuring block.

[0015] Furthermore, the first control valve includes a fifth control terminal and a sixth control terminal. The first and second ports of the switching valve are both connected to the safety shut-off valve assembly. The third port of the switching valve is connected to the tenth port of the shuttle valve assembly. The fourth port of the switching valve is connected to the fifth control terminal. The fifth port of the switching valve is connected to the ninth port of the shuttle valve assembly. The sixth port of the switching valve is connected to the sixth control terminal.

[0016] Furthermore, the first and second ports of the safety shut-off valve assembly are both connected to the pressure measuring block, the third port of the safety shut-off valve assembly is connected to the return oil tank, the fourth port of the safety shut-off valve assembly is connected to the second port of the switching valve, the fifth port of the safety shut-off valve assembly is connected to the first port of the switching valve, and the seventh and eighth ports of the switching valve are both connected to the return oil tank.

[0017] Furthermore, the first port of the handle is connected to the gear pump, the second port of the handle is connected to the oil tank, the third port of the handle is connected to the first port of the pressure measuring block, the fourth port of the handle is connected to the second port of the pressure measuring block, the third port of the pressure measuring block is connected to the first port of the safety shut-off valve assembly, and the fourth port of the pressure measuring block is connected to the second port of the safety shut-off valve assembly.

[0018] Furthermore, it also includes a controller, and the first pump, the second pump, the switching valve, the first pressure sensor, the second pressure sensor, the third pressure sensor, the fourth pressure sensor and the safety shut-off valve group are all electrically connected to the controller, which is electrically connected to a switching button, a left sliding interface and a right sliding interface.

[0019] Secondly, the present invention provides a working method for a hydraulic system for the travel of engineering machinery, based on the hydraulic system for the travel of engineering machinery described in the first aspect, including a conventional mode and a straight-line travel mode.

[0020] The conventional mode specifically includes:

[0021] If the switching button is not pressed, the switching valve will be de-energized.

[0022] The first motor is controlled by the first pump and the third control valve; wherein the third control valve is controlled by the travel pilot valve and the shuttle valve assembly.

[0023] The first pressure is obtained through the first pressure sensor, and the first pump is controlled according to the first pressure.

[0024] The second motor is controlled by the second pump and the second control valve; wherein the second control valve is controlled by the travel pilot valve and the shuttle valve assembly.

[0025] The second pressure is obtained through the second pressure sensor, and the second pump is controlled based on the second pressure.

[0026] The hydraulic cylinder is controlled by a first pump and a first control valve; wherein the first control valve is controlled by a handle and a switching valve.

[0027] The third pressure is obtained by the third pressure sensor, and the fourth pressure is obtained by the fourth pressure sensor. The first control valve is controlled according to the third pressure or the fourth pressure.

[0028] The straight-line walking mode specifically includes:

[0029] Press the switching button to energize the switching valve;

[0030] The first motor is controlled by the first pump and the third control valve, and the second motor is controlled by the second pump and the second control valve; wherein the third control valve and the second control valve are synchronously controlled by the handle, the switching valve, and the shuttle valve group.

[0031] The third pressure is obtained through the third pressure sensor, and the fourth pressure is obtained through the fourth pressure sensor. The first pump and the second pump are synchronously controlled according to the third pressure or the fourth pressure.

[0032] The first signal is obtained through the left sliding interface, and the second signal is obtained through the right sliding interface. The first pump and the second pump are further controlled according to the first signal or the second signal.

[0033] Specifically, when the first pressure sensor or the second pressure sensor has a pressure signal, the safety shut-off valve group is energized and reversed.

[0034] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0035] This hydraulic system for the construction machinery's travel, through the cooperation of a switching valve and a shuttle valve assembly, enables straight-line travel in excavator systems without single-foot pedal or lever-controlled straight-line travel functions. It achieves this without increasing the number or repositioning of pilot pressure sensors, simply by adding a shuttle valve assembly and a switching valve. Furthermore, during excavator travel, this invention allows for turning and directional correction without interrupting the movement, ensuring the continuity and convenience of the excavator's straight-line travel and improving operator comfort. Attached Figure Description

[0036] Figure 1 This is a connection diagram of a hydraulic system for the movement of engineering machinery according to an embodiment of the present invention;

[0037] Figure 2 This is a connection diagram of the controller provided according to an embodiment of the present invention.

[0038] In the diagram: 1. Oil tank; 2. First pump; 3. Second pump; 4. Gear pump; 5. First control valve; 6. Oil cylinder; 7. Second control valve; 8. Second motor; 9. Third control valve; 10. First motor; 11. Shuttle valve assembly; 12. Switching valve; 13. Travel pilot valve; 14. First pressure sensor; 15. Second pressure sensor; 16. Pressure measuring block; 17. Third pressure sensor; 18. Fourth pressure sensor; 19. Handle; 20. Safety shut-off valve assembly; 21. Controller; 22. Switching button; 23. Left sliding interface; 24. Right sliding interface. Detailed Implementation

[0039] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0040] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0041] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances. Example 1:

[0042] like Figure 1 As shown, the present invention provides a hydraulic system for the movement of engineering machinery, including a first pump 2, a second pump 3, a first control valve 5, a second control valve 7 and a third control valve 9;

[0043] The input ends of the first pump 2 and the second pump 3 are both connected to the oil tank 1; the output end of the first pump 2 is simultaneously connected to the first end of the third control valve 9 and the first end of the first control valve 5, the second and third ends of the first control valve 5 are both connected to the oil cylinder 6, the second and third ends of the third control valve 9 are both connected to the first motor 10, the output end of the second pump 3 is connected to the first end of the second control valve 7, the second and third ends of the second control valve 7 are both connected to the second motor 8, and the fourth ends of the first control valve 5, the second control valve 7, and the third control valve 9 are all connected to the oil tank 1.

[0044] The control ports of the second control valve 7 and the third control valve 9 are both connected to the shuttle valve assembly 11. The control port of the first control valve 5 and the shuttle valve assembly 11 are both connected to the switching valve 12. The shuttle valve assembly 11 is connected to the travel pilot valve 13. The switching valve 12 is connected to the handle 19. The travel pilot valve 13 and the handle 19 are both connected to the gear pump 4. The gear pump 4 is connected to the oil tank 1.

[0045] In one embodiment, the switching valve 12 and the handle 19 are connected via a safety shut-off valve assembly 20 and a pressure measuring block 16; the first port, second port, third port and fourth port of the shuttle valve assembly 11 are all connected to the travel pilot valve 13, and the ninth port and tenth port of the shuttle valve assembly 11 are all connected to the switching valve 12.

[0046] The control port of the third control valve 9 includes a first control terminal and a second control terminal. The first control terminal is connected to the fifth port of the shuttle valve assembly 11, and the second control terminal is connected to the sixth port of the shuttle valve assembly 11.

[0047] The control port of the second control valve 7 includes a third control terminal and a fourth control terminal. The third control terminal is connected to the seventh port of the shuttle valve assembly 11, and the fourth control terminal is connected to the eighth port of the shuttle valve assembly 11.

[0048] In one embodiment, the first port of the travel pilot valve 13 is connected to the gear pump 4, the second port of the travel pilot valve 13 is connected to the oil tank 1, the third port of the travel pilot valve 13 is connected to the first port of the shuttle valve assembly 11, the fourth port of the travel pilot valve 13 is connected to the second port of the shuttle valve assembly 11, the fifth port of the travel pilot valve 13 is connected to the third port of the shuttle valve assembly 11, and the sixth port of the travel pilot valve 13 is connected to the fourth port of the shuttle valve assembly 11.

[0049] Specifically, Figure 1In the diagram, 901 is the first control terminal, 902 is the second control terminal, 701 is the third control terminal, 702 is the fourth control terminal, 501 is the fifth control terminal, 502 is the sixth control terminal, 111 is the first port of shuttle valve assembly 11, 112 is the second port of shuttle valve assembly 11, 113 is the third port of shuttle valve assembly 11, 114 is the fourth port of shuttle valve assembly 11, 115 is the fifth port of shuttle valve assembly 11, 116 is the sixth port of shuttle valve assembly 11, 117 is the seventh port of shuttle valve assembly 11, 118 is the eighth port of shuttle valve assembly 11, 119 is the ninth port of shuttle valve assembly 11, and 120... That is, the tenth port of shuttle valve assembly 11, 131 is the first port of travel pilot valve 13, 132 is the second port of travel pilot valve 13, 133 is the third port of travel pilot valve 13, 134 is the fourth port of travel pilot valve 13, 135 is the fifth port of travel pilot valve 13, 136 is the sixth port of travel pilot valve 13, 121 is the first port of switching valve 12, 122 is the second port of switching valve 12, 123 is the third port of switching valve 12, 124 is the fourth port of switching valve 12, 125 is the fifth port of switching valve 12, and 126 is the sixth port of switching valve 12.

[0050] Specifically, the first pump 2 supplies oil to the cylinder 6 and the first motor 10, the second pump 3 supplies oil to the second motor 8, and the gear pump 4 supplies oil to the pilot control oil circuit; the right forward travel pilot pressure output port 133 of the travel pilot valve 13 is connected to port 111 of the shuttle valve group 11, the right backward travel pilot pressure output port 134 is connected to port 112 of the shuttle valve group 11, the left forward travel pilot pressure output port 135 is connected to port 113 of the shuttle valve group 11, and the left backward travel pilot pressure output port 136 is connected to port 114 of the shuttle valve group 11.

[0051] Port 115 of shuttle valve assembly 11 is connected to the first control terminal 901 of the third control valve 9, port 116 of shuttle valve assembly 11 is connected to the second control terminal 902 of the third control valve 9, port 117 of shuttle valve assembly 11 is connected to the third control terminal 701 of the second control valve 7, and port 118 of shuttle valve assembly 11 is connected to the fourth control terminal 702 of the second control valve 7.

[0052] In one embodiment, a first pressure sensor 14 and a second pressure sensor 15 are connected to the travel pilot valve 13; a third pressure sensor 17 and a fourth pressure sensor 18 are connected to the pressure measuring block 16; the first control valve 5 includes a fifth control terminal and a sixth control terminal; the first port and the second port of the switching valve 12 are both connected to the safety shut-off valve assembly 20; the third port of the switching valve 12 is connected to the tenth port of the shuttle valve assembly 11; the fourth port of the switching valve 12 is connected to the fifth control terminal; the fifth port of the switching valve 12 is connected to the ninth port of the shuttle valve assembly 11; and the sixth port of the switching valve 12 is connected to the sixth control terminal; the first port and the second port of the safety shut-off valve assembly 20 are both connected to the pressure measuring block 16; the third port of the safety shut-off valve assembly 20 is connected to the return oil tank; the fourth port of the safety shut-off valve assembly 20 is connected to the second port of the switching valve 12; the fifth port of the safety shut-off valve assembly 20 is connected to the first port of the switching valve 12; and the seventh port and the eighth port of the switching valve 12 are both connected to the return oil tank.

[0053] In one embodiment, the first port of the handle 19 is connected to the gear pump 4, the second port of the handle 19 is connected to the oil tank 1, the third port of the handle 19 is connected to the first port of the pressure measuring block 16, the fourth port of the handle 19 is connected to the second port of the pressure measuring block 16, the third port of the pressure measuring block 16 is connected to the first port of the safety shut-off valve assembly 20, and the fourth port of the pressure measuring block 16 is connected to the second port of the safety shut-off valve assembly 20.

[0054] like Figure 2 As shown, in one embodiment, it further includes a controller 21. The first pump 2, the second pump 3, the switching valve 12, the first pressure sensor 14, the second pressure sensor 15, the third pressure sensor 17, the fourth pressure sensor 18, and the safety shut-off valve group 20 are all electrically connected to the controller 21. The controller 21 is electrically connected to a switching button 22, a left sliding interface 23, and a right sliding interface 24.

[0055] Specifically, Figure 1 In the diagram, 191 is the first port of handle 19, 192 is the second port of handle 19, 193 is the third port of handle 19, 194 is the fourth port of handle 19, 161 is the first port of pressure measuring block 16, 162 is the second port of pressure measuring block 16, 163 is the third port of pressure measuring block 16, 164 is the fourth port of pressure measuring block 16, 201 is the first port of safety shut-off valve assembly 20, 202 is the second port of safety shut-off valve assembly 20, 203 is the third port of safety shut-off valve assembly 20, 204 is the fourth port of safety shut-off valve assembly 20, and 205 is the fifth port of safety shut-off valve assembly 20. Figure 2The ST mode switching button 22 is the switching button 22, the left handle slide key left slide interface 23 is the left slide interface 23, the left handle slide key right slide interface 24 is the right slide interface 24, the right travel pilot pressure sensor 14 is the first pressure sensor 14, the left travel pilot pressure sensor 15 is the second pressure sensor 15, the stick outward swing pilot pressure sensor 17 is the third pressure sensor 17, the stick inward retraction pilot pressure sensor 18 is the fourth pressure sensor 18, the plunger pump 2 is the first pump 2, and the plunger pump 3 is the second pump 3.

[0056] Specifically, the pilot pressure output port 193 of the outward swing of the stick of the handle 19 is connected to port 161 of the pressure measuring block 16, and the pilot pressure output port 194 of the inward swing of the stick of the handle 19 is connected to port 162 of the pressure measuring block 16; port 121 of the switching valve 12 is connected to port 163 of the pressure measuring block 16, port 122 of the switching valve 12 is connected to port 164 of the pressure measuring block 16, and port 123 of the switching valve 12 is connected to port 120 of the shuttle valve assembly 11. The 124 port of the switching valve 12 is connected to the fifth control port 501, the 125 port of the switching valve 12 is connected to the 119 port of the shuttle valve group 11, and the 126 port of the switching valve 12 is connected to the sixth control port 502. When the switching valve 12 is not energized, the 121 port and the 124 port are connected, and the 122 port and the 126 port are connected. When the switching valve 12 is energized, the valve core reverses, and the 121 port and the 123 port are connected, and the 122 port and the 125 port are connected.

[0057] When the switch button 22 is not pressed, it is in normal mode, as follows:

[0058] Switching valve 12 is not energized; the pilot pressure from the right travel forward pilot pressure output port 133 passes through port 111 of shuttle valve assembly 11, and is output from port 115 of shuttle valve assembly 11 to the first control terminal 901 of the third control valve 9, causing the third control valve 9 to switch. At the same time, the first pressure sensor 14 detects the effective pilot pressure and sends an electrical signal to the controller 21. After processing by the controller 21, an electrical signal is sent to the first pump 2, and the working oil of the first pump 2 enters the first motor 10. 10 Forward; Rightward and Reverse Pilot Pressure Output Port 134 The pilot pressure passes through port 112 of shuttle valve group 11, and through shuttle valve group 11, it is output from port 116 of shuttle valve group 11 to the second control terminal 902 of the third control valve 9, causing the third control valve 9 to switch. At the same time, the first pressure sensor 14 detects the effective pilot pressure and sends an electrical signal to the controller 21. After processing by the controller 21, an electrical signal is sent to the first pump 2, and the working oil of the first pump 2 enters the first motor 10, and the first motor 10 reverses.

[0059] The pilot pressure from the left-walking forward pilot pressure output port 135 passes through port 113 of the shuttle valve assembly 11, and is output from port 117 of the shuttle valve assembly 11 to the third control terminal 701 of the second control valve 7, causing the second control valve 7 to switch. Simultaneously, the second pressure sensor 15 detects the effective pilot pressure and sends an electrical signal to the controller 21. After processing by the controller 21, an electrical signal is sent to the second pump 3, causing the working oil of the second pump 3 to enter the second motor 8, which then moves forward. The left-walking reverse pilot pressure... The pilot pressure at output port 136 passes through port 114 of shuttle valve assembly 11, and is output from port 118 of shuttle valve assembly 11 to the fourth control terminal 702 of the second control valve 7, causing the second control valve 7 to switch. At the same time, the second pressure sensor 15 detects the effective pilot pressure and sends an electrical signal to the controller 21. After processing by the controller 21, an electrical signal is sent to the second pump 3, and the working oil of the second pump 3 enters the second motor 8, causing the second motor 8 to move forward. Optionally, both the first pump 2 and the second pump 3 are plunger pumps.

[0060] When the stick of handle 19 swings outward, the pilot pressure at the pilot pressure output port 193 passes through the pressure measuring block 16, is conducted from port 121 to port 124 of the switching valve 12, and is output to the fifth control terminal 501 of the first control valve 5, causing the first control valve 5 to switch. At the same time, the third pressure sensor 17 detects the effective pilot pressure and sends an electrical signal to the controller 21. After processing by the controller 21, an electrical signal is sent to the first pump 2, and the working oil of the first pump 2 enters the rod chamber of the cylinder 6, causing the stick to swing outward. When the stick of handle 19 retracts inward, the pilot pressure at the pilot pressure output port 194 passes through the pressure measuring block 16, is conducted from port 122 to port 126 of the switching valve 12, and is output to the sixth control terminal 502 of the first control valve 5, causing the first control valve 5 to switch. At the same time, the fourth pressure sensor 18 detects the effective pilot pressure and sends an electrical signal to the controller 21. After processing by the controller 21, an electrical signal is sent to the first pump 2, and the working oil of the first pump 2 enters the rodless chamber of the cylinder 6, causing the stick to retract.

[0061] When the switch button 22 is pressed, the straight-line walking mode is activated, as detailed below:

[0062] When switching valve 12 is energized and reversed, the pilot pressure output port 193 of the stick outward swings through the pressure measuring block 16, and flows from port 121 of switching valve 12 to port 123, entering port 120 of shuttle valve assembly 11. Through shuttle valve assembly 11, the pressure is output from port 115 to the first control terminal 901 of the third control valve 9, and simultaneously from port 117 of shuttle valve assembly 11 to the third control terminal 701 of the second control valve 7, causing the third control valve 9 and the second control valve 7 to reverse simultaneously, and the first motor 10 and the second motor 8 to advance simultaneously. When the stick inward swings through the pressure measuring block, the pilot pressure output port 194 flows through the pressure measuring block... 16. The switching valve 12 is connected from port 122 to port 125, and enters port 119 of the shuttle valve group 11. The output from port 116 of the shuttle valve group 11 is sent to the second control terminal 902 of the third control valve 9. At the same time, the output from port 118 of the shuttle valve group 11 is sent to the fourth control terminal 702 of the second control valve 7, so that the third control valve 9 and the second control valve 7 switch simultaneously, and the first motor 10 and the second motor 8 retract simultaneously. The third pressure sensor 17 or the fourth pressure sensor 18 detects the effective pilot pressure and sends an electrical signal to the controller 21. After processing by the controller 21, an electrical signal is sent to the first pump 2 and the second pump 3.

[0063] In straight-line driving mode, steering and direction correction functions can be achieved through the following operations:

[0064] When the left handle slider is slid to the left, the left slider interface 23 outputs an electrical signal to the controller 21. After processing, the controller 21, based on the electrical signal from the third pressure sensor 17 or the fourth pressure sensor 18, sends an increased displacement current signal to the first pump 2, increasing the flow rate from the first pump 2 to the first motor 10, thus accelerating rightward movement. Simultaneously, it sends a decreased displacement current signal to the second pump 3, decreasing the flow rate from the second pump 3 to the second motor 8, thus decelerating leftward movement. The difference in left and right movement speeds causes the excavator to veer to the left. When the left handle slider is slid to the right, the right slider interface 24 outputs an electrical signal to the controller 21. After processing, the controller 21 sends a decreased displacement current signal to the first pump 2, decreasing the flow rate from the first pump 2 to the first motor 10, thus decelerating rightward movement. Simultaneously, it sends an increased displacement current signal to the second pump 3, increasing the flow rate from the second pump 3 to the second motor 8, thus accelerating leftward movement. The difference in left and right movement speeds causes the excavator to veer to the right.

[0065] Based on the sliding stroke of the left handle slider, the proportional adjustment controller 21 outputs current signals to the first pump 2 and the second pump 3 to proportionally control the displacement of the first pump 2 and the second pump 3, and further control the speed difference between the second motor 8 and the first motor 10, so as to realize the proportional control of the deflection radius when the excavator travels in a straight line, making it easier for the driver to turn or correct the direction according to the actual situation of the construction scene.

[0066] In straight-line driving mode, the sharp turn function can be activated through the following steps:

[0067] When a sharp turn is required during operation, or when the left and right travel motors rotate in opposite directions, the driver depresses the travel pilot valve 13. At this time, if either the first pressure sensor 14 or the second pressure sensor 15 has a pressure signal, the controller 21 will energize the safety shut-off valve assembly 20 to reverse the direction, cutting off the control oil circuit of the handle. At this time, the steering can be controlled through the travel pilot valve 13. After the steering is completed, the travel pilot valve 13 is released. At this time, neither the first pressure sensor 14 nor the second pressure sensor 15 has a pressure signal. The controller 21 will de-energize and reset the safety shut-off valve assembly 20, and the handle 19 will continue to control the excavator's movement.

[0068] This invention, through the cooperation of switching valve 12 and shuttle valve assembly 11, enables straight-line travel in excavator systems without single-foot pedal or handle-controlled straight-line travel functions, without increasing the number of pilot pressure sensors or moving their positions. It only requires adding shuttle valve assembly 11 and switching valve 12. Furthermore, during excavator travel, this invention allows for turning and directional correction without interrupting travel, ensuring the continuity and convenience of straight-line travel and improving operator comfort.

[0069] In the straight-line walking mode, if an emergency turning situation occurs while controlling straight-line walking, the travel pilot valve 13 can immediately intervene and simultaneously cut off the oil circuit for controlling straight-line walking by the handle to ensure steering safety. Example 2:

[0070] This invention provides a working method for a hydraulic system for the movement of engineering machinery, based on the hydraulic system for the movement of engineering machinery described in Embodiment 1, including a conventional mode and a straight-line movement mode;

[0071] The conventional mode specifically includes:

[0072] If the switching button 22 is not pressed, the switching valve 12 will be de-energized;

[0073] The first motor 10 is controlled by the first pump 2 and the third control valve 9; wherein the third control valve 9 is controlled by the travel pilot valve 13 and the shuttle valve group 11.

[0074] The first pressure is obtained by the first pressure sensor 14, and the first pump 2 is controlled according to the first pressure;

[0075] The second motor 8 is controlled by the second pump 3 and the second control valve 7; wherein the second control valve 7 is controlled by the travel pilot valve 13 and the shuttle valve group 11.

[0076] The second pressure is obtained by the second pressure sensor 15, and the second pump 3 is controlled according to the second pressure.

[0077] The cylinder 6 is controlled by the first pump 2 and the first control valve 5; wherein the first control valve 5 is controlled by the handle 19 and the switching valve 12.

[0078] The third pressure is obtained by the third pressure sensor 17 and the fourth pressure is obtained by the fourth pressure sensor 18. The first control valve 5 is controlled according to the third pressure or the fourth pressure.

[0079] The straight-line walking mode specifically includes:

[0080] Press the switching button 22 to energize the switching valve 12;

[0081] The first motor 10 is controlled by the first pump 2 and the third control valve 9, and the second motor 8 is controlled by the second pump 3 and the second control valve 7; wherein the third control valve 9 and the second control valve 7 are synchronously controlled by the handle 19, the switching valve 12, and the shuttle valve group 11.

[0082] The third pressure is obtained by the third pressure sensor 17 and the fourth pressure is obtained by the fourth pressure sensor 18. The first pump 2 and the second pump 3 are synchronously controlled according to the third pressure or the fourth pressure.

[0083] The first signal is obtained through the left sliding interface 23, and the second signal is obtained through the right sliding interface 24. The first pump 2 and the second pump 3 are further controlled according to the first signal or the second signal.

[0084] When the first pressure sensor 14 or the second pressure sensor 15 has a pressure signal, the safety shut-off valve group 20 is energized and reversed.

[0085] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A hydraulic system for the movement of engineering machinery, characterized in that, Includes a first pump (2), a second pump (3), a first control valve (5), a second control valve (7), and a third control valve (9); The input ends of the first pump (2) and the second pump (3) are both connected to the oil tank (1); the output end of the first pump (2) is simultaneously connected to the first end of the third control valve (9) and the first end of the first control valve (5); the second and third ends of the first control valve (5) are both connected to the oil cylinder (6); the second and third ends of the third control valve (9) are both connected to the first motor (10); the output end of the second pump (3) is connected to the first end of the second control valve (7); the second and third ends of the second control valve (7) are both connected to the second motor (8); the fourth end of the first control valve (5), the fourth end of the second control valve (7) and the fourth end of the third control valve (9) are all connected to the oil tank (1); The control ports of the second control valve (7) and the third control valve (9) are both connected to the shuttle valve assembly (11). The control ports of the first control valve (5) and the shuttle valve assembly (11) are both connected to the switching valve (12). The shuttle valve assembly (11) is connected to the travel pilot valve (13). The switching valve (12) is connected to the handle (19). The travel pilot valve (13) and the handle (19) are both connected to the gear pump (4). The gear pump (4) is connected to the oil tank (1).

2. The hydraulic system for traveling engineering machinery according to claim 1, characterized in that, The switching valve (12) and the handle (19) are connected via a safety shut-off valve assembly (20) and a pressure measuring block (16).

3. The hydraulic system for traveling engineering machinery according to claim 2, characterized in that, The first, second, third and fourth ports of the shuttle valve assembly (11) are all connected to the travel pilot valve (13), and the ninth and tenth ports of the shuttle valve assembly (11) are all connected to the switching valve (12). The control port of the third control valve (9) includes a first control terminal and a second control terminal. The first control terminal is connected to the fifth port of the shuttle valve assembly (11), and the second control terminal is connected to the sixth port of the shuttle valve assembly (11). The control port of the second control valve (7) includes a third control terminal and a fourth control terminal. The third control terminal is connected to the seventh port of the shuttle valve assembly (11), and the fourth control terminal is connected to the eighth port of the shuttle valve assembly (11).

4. The hydraulic system for traveling engineering machinery according to claim 3, characterized in that, The first port of the travel pilot valve (13) is connected to the gear pump (4), the second port of the travel pilot valve (13) is connected to the oil tank (1), the third port of the travel pilot valve (13) is connected to the first port of the shuttle valve assembly (11), the fourth port of the travel pilot valve (13) is connected to the second port of the shuttle valve assembly (11), the fifth port of the travel pilot valve (13) is connected to the third port of the shuttle valve assembly (11), and the sixth port of the travel pilot valve (13) is connected to the fourth port of the shuttle valve assembly (11).

5. The hydraulic system for traveling engineering machinery according to claim 2, characterized in that, The travel pilot valve (13) is connected to a first pressure sensor (14) and a second pressure sensor (15); the pressure measuring block (16) is connected to a third pressure sensor (17) and a fourth pressure sensor (18).

6. The hydraulic system for traveling engineering machinery according to claim 4, characterized in that, The first control valve (5) includes a fifth control terminal and a sixth control terminal. The first port and the second port of the switching valve (12) are both connected to the safety shut-off valve group (20). The third port of the switching valve (12) is connected to the tenth port of the shuttle valve group (11). The fourth port of the switching valve (12) is connected to the fifth control terminal. The fifth port of the switching valve (12) is connected to the ninth port of the shuttle valve group (11). The sixth port of the switching valve (12) is connected to the sixth control terminal.

7. The hydraulic system for traveling engineering machinery according to claim 6, characterized in that, The first and second ports of the safety shut-off valve assembly (20) are both connected to the pressure measuring block (16), the third port of the safety shut-off valve assembly (20) is connected to the return oil tank, the fourth port of the safety shut-off valve assembly (20) is connected to the second port of the switching valve (12), the fifth port of the safety shut-off valve assembly (20) is connected to the first port of the switching valve (12), and the seventh and eighth ports of the switching valve (12) are both connected to the return oil tank.

8. The hydraulic system for traveling engineering machinery according to claim 7, characterized in that, The first port of the handle (19) is connected to the gear pump (4), the second port of the handle (19) is connected to the oil tank (1), the third port of the handle (19) is connected to the first port of the pressure measuring block (16), the fourth port of the handle (19) is connected to the second port of the pressure measuring block (16), the third port of the pressure measuring block (16) is connected to the first port of the safety shut-off valve assembly (20), and the fourth port of the pressure measuring block (16) is connected to the second port of the safety shut-off valve assembly (20).

9. The hydraulic system for traveling engineering machinery according to claim 5, characterized in that, It also includes a controller (21), the first pump (2), the second pump (3), the switching valve (12), the first pressure sensor (14), the second pressure sensor (15), the third pressure sensor (17), the fourth pressure sensor (18) and the safety shut-off valve group (20) are all electrically connected to the controller (21), and the controller (21) is electrically connected to a switching button (22), a left sliding interface (23) and a right sliding interface (24).

10. A method for operating a hydraulic system for the travel of engineering machinery, based on the hydraulic system for the travel of engineering machinery as described in claim 9, characterized in that, Includes both standard mode and straight-line walking mode; The conventional mode specifically includes: Without pressing the switching button (22), the switching valve (12) is de-energized; The first motor (10) is controlled by the first pump (2) and the third control valve (9); wherein the third control valve (9) is controlled by the travel pilot valve (13) and the shuttle valve group (11); The first pressure is obtained by the first pressure sensor (14), and the first pump (2) is controlled according to the first pressure; The second motor (8) is controlled by the second pump (3) and the second control valve (7); wherein the second control valve (7) is controlled by the travel pilot valve (13) and the shuttle valve assembly (11); The second pressure is obtained by the second pressure sensor (15), and the second pump (3) is controlled according to the second pressure; The cylinder (6) is controlled by the first pump (2) and the first control valve (5); wherein the first control valve (5) is controlled by the handle (19) and the switching valve (12); The third pressure is obtained by the third pressure sensor (17), and the fourth pressure is obtained by the fourth pressure sensor (18). The first control valve (5) is controlled according to the third pressure or the fourth pressure. The straight-line walking mode specifically includes: Press the switching button (22) to energize the switching valve (12); The first motor (10) is controlled by the first pump (2) and the third control valve (9), and the second motor (8) is controlled by the second pump (3) and the second control valve (7); wherein the third control valve (9) and the second control valve (7) are synchronously controlled by the handle (19), the switching valve (12), and the shuttle valve group (11); The third pressure is obtained through the third pressure sensor (17), and the fourth pressure is obtained through the fourth pressure sensor (18). The first pump (2) and the second pump (3) are synchronously controlled according to the third pressure or the fourth pressure. The first signal is obtained through the left sliding interface (23), and the second signal is obtained through the right sliding interface (24). The first pump (2) and the second pump (3) are further controlled according to the first signal or the second signal. When the first pressure sensor (14) or the second pressure sensor (15) has a pressure signal, the safety shut-off valve group (20) is energized and reversed.

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