Engineering machinery walking hydraulic system and working method thereof

Abstract

The invention 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 continuity and convenience of linear walking of an excavator are influenced as original double walking pedals need to be used for correcting the direction in the prior art. The system comprises a first pump, a second pump, a first control valve, a second control valve and a third control valve, input ends of the first pump and the second pump are connected with the oil tank; the output end of the first pump is simultaneously connected with the first end of the third control valve and the first end of the first control valve; under the condition that the number of pilot pressure sensors does not need to be increased or the positions of the pilot pressure sensors do not need to be moved, only the shuttle valve set and the switching valve are added, and the linear walking function can be achieved; and under the condition that advancing is not stopped, turning and direction correction can be conducted on the excavator, continuity and convenience of linear walking of the excavator are guaranteed, and the operation comfort of a driver is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to an engineering machinery walking hydraulic system and a working method thereof, and belongs to the technical field of engineering machinery. BACKGROUND

[0002] The walking function of a hydraulic-controlled crawler excavator is controlled by two walking pedals, the left walking pedal controls the left walking motor, the right walking pedal controls the right walking motor, the two feet simultaneously step on the walking pedals in the same direction to realize straight walking, the two feet step on the walking pedals at different strokes to realize turning during walking, and the two feet step on the walking pedals forward and backward to realize in-place turning. In the field of excavator walking control, in order to improve the convenience of the driver's operation, the straight walking control function is simplified in design, and a single pedal is usually added to control the straight walking of the excavator. The straight walking controlled by the single pedal cannot turn, and the driver needs to use the original double walking pedals to turn. Due to the difference between the actual construction ground and the ideal ground environment, the excavator often deviates to the left or right during straight walking, and the driver needs to use the original double walking pedals to correct. During the long-distance walking of the excavator, the driver needs to move his feet between the single pedal and the double walking pedals for turning and direction correction, and the walking of the excavator will be interrupted when the pedals are switched, which will reduce the continuity of the walking of the excavator and the comfort of the driver.

[0003] In summary, the existing walking hydraulic system usually adds a single pedal to control the straight walking of the excavator, which does not have a turning function and requires the driver to use the original double walking pedals to turn, and the original double walking pedals are also needed to correct the direction, which affects the continuity and convenience of the straight walking of the excavator and the comfort of the driver's operation. SUMMARY

[0004] The present application aims to overcome the deficiencies in the prior art and provide an engineering machinery walking hydraulic system and a working method thereof. By switching the valve and the shuttle valve group, the straight walking function can be realized without increasing the number of pilot pressure sensors or moving the position of the pilot pressure sensor in an excavator system without a single pedal straight walking or handle control straight walking function. During the walking of the excavator, the present application can turn and correct the direction without interrupting the walking, ensuring the continuity and convenience of the straight walking of the excavator and improving the comfort of the driver's operation.

[0005] To solve the above technical problems, the present application is realized by using the following technical scheme: In a first aspect, the present application provides an engineering machinery walking hydraulic system, comprising 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 second end and the third end of the first control valve are connected with a cylinder, the second end and the third end of the third control valve are connected with a first motor, the output end of the second pump is connected with the first end of the second control valve, the second end and the third end of the second control valve are connected with a second motor, the fourth end of the first control valve, the fourth end of the second control valve and the fourth end of the third control valve are connected with the oil tank. The control ports of the second control valve and the third control valve are connected with a shuttle valve group, the control port of the first control valve and the shuttle valve group are connected with a switch valve, the shuttle valve group is connected with a travel pilot valve, the switch valve is connected with a handle, the travel pilot valve and the handle are connected with a gear pump, and the gear pump is connected with the oil tank.

[0006] Further, the switch valve and the handle are connected through a safety cut-off valve group and a pressure measuring block.

[0007] Further, the first port, the second port, the third port and the fourth port of the shuttle valve group are connected with the travel pilot valve, and the ninth port and the tenth port of the shuttle valve group are connected with the switch valve. The control port of the third control valve comprises a first control end and a second control end, the first control end is connected with the fifth port of the shuttle valve group, and the second control end is connected with the sixth port of the shuttle valve group. The control port of the second control valve comprises a third control end and a fourth control end, the third control end is connected with the seventh port of the shuttle valve group, and the fourth control end is connected with the eighth port of the shuttle valve group.

[0008] Further, the first port of the travel pilot valve is connected with the gear pump, the second port of the travel pilot valve is connected with the oil tank, the third port of the travel pilot valve is connected with the first port of the shuttle valve group, the fourth port of the travel pilot valve is connected with the second port of the shuttle valve group, the fifth port of the travel pilot valve is connected with the third port of the shuttle valve group, and the sixth port of the travel pilot valve is connected with the fourth port of the shuttle valve group.

[0009] Further, the travel pilot valve is connected with a first pressure sensor and a second pressure sensor, and the pressure measuring block is connected with a third pressure sensor and a fourth pressure sensor.

[0010] Further, the first control valve comprises a fifth control end and a sixth control end, the first port and the second port of the switch valve are connected with the safety cut-off valve group, the third port of the switch valve is connected with the tenth port of the shuttle valve group, the fourth port of the switch valve is connected with the fifth control end, the fifth port of the switch valve is connected with the ninth port of the shuttle valve group, and the sixth port of the switch valve is connected with the sixth control end.

[0011] Further, the first port and the second port of the safety cut-off valve group are connected with a pressure block, the third port of the safety cut-off valve group is connected with an oil return tank, the fourth port of the safety cut-off valve group is connected with the second port of the switch valve, the fifth port of the safety cut-off valve group is connected with the first port of the switch valve, and the seventh port and the eighth port of the switch valve are connected with the oil return tank.

[0012] Further, the first port of the handle is connected with the gear pump, the second port of the handle is connected with the oil tank, the third port of the handle is connected with the first port of the pressure block, the fourth port of the handle is connected with the second port of the pressure block, the third port of the pressure block is connected with the first port of the safety cut-off valve group, and the fourth port of the pressure block is connected with the second port of the safety cut-off valve group.

[0013] Further, a controller is further included, the first pump, the second pump, the switch valve, the first pressure sensor, the second pressure sensor, the third pressure sensor, the fourth pressure sensor and the safety cut-off valve group are electrically connected with the controller, and the controller is electrically connected with a switch button, a left sliding interface and a right sliding interface.

[0014] In a second aspect, the application provides a working method of the engineering machinery walking hydraulic system, based on the engineering machinery walking hydraulic system in the first aspect, including a conventional mode and a straight-line walking mode. The conventional mode specifically includes: The switch button is not pressed, so that the switch valve is in a power-off state; The first motor is controlled by the first pump and the third control valve, and the third control valve is controlled by the walking pilot valve and the shuttle valve group; The first pressure is obtained by the first pressure sensor, and the first pump is controlled according to the first pressure; The second motor is controlled by the second pump and the second control valve, and the second control valve is controlled by the walking pilot valve and the shuttle valve group; The second pressure is obtained by the second pressure sensor, and the second pump is controlled according to the second pressure; The oil cylinder is controlled by the first pump and the first control valve, and the first control valve is controlled by the handle and the switch valve; The third pressure is obtained through a third pressure sensor, the fourth pressure is obtained through a fourth pressure sensor, and the first control valve is controlled according to the third pressure or the fourth pressure; The straight-line walking mode specifically comprises: The switching button is pressed, so that the switching valve is in an energized state; The first motor is controlled through the first pump and the third control valve, and the second motor is controlled through the second pump and the second control valve; wherein the third control valve and the second control valve are synchronously controlled through the handle, the switching valve, and the shuttle valve group; The third pressure is obtained through a third pressure sensor, the fourth pressure is obtained through a fourth pressure sensor, and the first control valve is controlled according to the third pressure or the fourth pressure; The first signal is obtained through the left sliding interface, the second signal is obtained through the right sliding interface, and the first pump and the second pump are further controlled according to the first signal or the second signal; When the first pressure sensor or the second pressure sensor has a pressure signal, the safety cut-off valve group is controlled to be energized and reversed.

[0015] Compared with the prior art, the present application has the following beneficial effects: The engineering machinery walking hydraulic system, through cooperation of the switching valve and the shuttle valve group, can realize the straight-line walking function in the excavator system without single-foot-pedal straight-line walking or handle-controlled straight-line walking function, without increasing the number of pilot pressure sensors or moving the position of the pilot pressure sensor, and only by increasing the shuttle valve group and the switching valve; and in the process of excavator walking, the excavator can be turned and direction-corrected without interrupting the walking, ensuring the continuity and convenience of the excavator straight-line walking and improving the operation comfort of the driver. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a connection schematic diagram of an engineering machinery walking hydraulic system according to an embodiment of the present application; Figure 2 is a connection schematic diagram of a controller according to an embodiment of the present application.

[0017] In the figure: 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 group; 12, switching valve; 13, walking 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 cut-off valve group; 21, controller; 22, switching button; 23, left sliding interface; 24, right sliding interface. DETAILED DESCRIPTION

[0018] The application will be further described below with reference to the drawings. The following examples are only used to more clearly illustrate the technical solutions of the application, and cannot be used to limit the protection scope of the application.

[0019] In the description of the present application, it needs to be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" and the like are only for the purpose of description and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0020] In the description of the present application, it needs to be understood that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances. Example one:

[0021] As shown in Figure 1 The present application provides an engineering machinery walking hydraulic system, comprising 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 connected with an oil tank 1; the output end of the first pump 2 is connected with the first end of the third control valve 9 and the first end of the first control valve 5, the second end and the third end of the first control valve 5 are connected with a cylinder 6, the second end and the third end of the third control valve 9 are connected with a first motor 10, the output end of the second pump 3 is connected with the first end of the second control valve 7, the second end and the third end of the second control valve 7 are connected with a 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 connected with the oil tank 1; The control port of the second control valve 7 and the control port of the third control valve 9 are connected with the shuttle valve group 11, the control port of the first control valve 5 and the shuttle valve group 11 are connected with the switch valve 12, the shuttle valve group 11 is connected with the travel pilot valve 13, the switch valve 12 is connected with the handle 19, the travel pilot valve 13 and the handle 19 are connected with the gear pump 4, and the gear pump 4 is connected with the oil tank 1.

[0022] In an embodiment, the switch valve 12 and the handle 19 are connected through a safety cut-off valve group 20 and a pressure measuring block 16; the first port, the second port, the third port and the fourth port of the shuttle valve group 11 are connected with the travel pilot valve 13, and the ninth port and the tenth port of the shuttle valve group 11 are connected with the switch valve 12. The control port of the third control valve 9 includes a first control end and a second control end, the first control end is connected with the fifth port of the shuttle valve group 11, and the second control end is connected with the sixth port of the shuttle valve group 11. The control port of the second control valve 7 includes a third control end and a fourth control end, the third control end is connected with the seventh port of the shuttle valve group 11, and the fourth control end is connected with the eighth port of the shuttle valve group 11.

[0023] In an embodiment, the first port of the travel pilot valve 13 is connected with the gear pump 4, the second port of the travel pilot valve 13 is connected with the oil tank 1, the third port of the travel pilot valve 13 is connected with the first port of the shuttle valve group 11, the fourth port of the travel pilot valve 13 is connected with the second port of the shuttle valve group 11, the fifth port of the travel pilot valve 13 is connected with the third port of the shuttle valve group 11, and the sixth port of the travel pilot valve 13 is connected with the fourth port of the shuttle valve group 11.

[0024] Specifically, Figure 1901, 902, 701, 702, 501, 502, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 131, 132, 133, 134, 135, 136, 121, 122, 123, 124, 125, 126.

[0025] Specifically, the first pump 2 supplies oil for the oil cylinder 6 and the first motor 10, the second pump 3 supplies oil for the second motor 8, and the gear pump 4 supplies oil for the pilot control oil circuit; the right travel forward pilot pressure output port 133 of the travel pilot valve 13 is connected with the 111 port of the shuttle valve group 11, the right travel backward pilot pressure output port 134 is connected with the 112 port of the shuttle valve group 11, the left travel forward pilot pressure output port 135 is connected with the 113 port of the shuttle valve group 11, and the left travel backward pilot pressure output port 136 is connected with the 114 port of the shuttle valve group 11. The 115 port of the shuttle valve group 11 is connected with the first control end 901 of the third control valve 9, the 116 port of the shuttle valve group 11 is connected with the second control end 902 of the third control valve 9, the 117 port of the shuttle valve group 11 is connected with the third control end 701 of the second control valve 7, and the 118 port of the shuttle valve group 11 is connected with the fourth control end 702 of the second control valve 7.

[0026] An embodiment, the walking pilot valve 13 is connected with a first pressure sensor 14 and a second pressure sensor 15; the load cell 16 is connected with a third pressure sensor 17 and a fourth pressure sensor 18; the first control valve 5 includes a fifth control end and a sixth control end, the first port and the second port of the switch valve 12 are connected with the safety cut-off valve group 20, the third port of the switch valve 12 is connected with the tenth port of the shuttle valve group 11, the fourth port of the switch valve 12 is connected with the fifth control end, the fifth port of the switch valve 12 is connected with the ninth port of the shuttle valve group 11, the sixth port of the switch valve 12 is connected with the sixth control end; the first port and the second port of the safety cut-off valve group 20 are connected with the load cell 16, the third port of the safety cut-off valve group 20 is connected with the oil return tank, the fourth port of the safety cut-off valve group 20 is connected with the second port of the switch valve 12, the fifth port of the safety cut-off valve group 20 is connected with the first port of the switch valve 12, the seventh port and the eighth port of the switch valve 12 are connected with the oil return tank.

[0027] An embodiment, the first port of the handle 19 is connected with the gear pump 4, the second port of the handle 19 is connected with the oil tank 1, the third port of the handle 19 is connected with the first port of the load cell 16, the fourth port of the handle 19 is connected with the second port of the load cell 16, the third port of the load cell 16 is connected with the first port of the safety cut-off valve group 20, the fourth port of the load cell 16 is connected with the second port of the safety cut-off valve group 20.

[0028] As shown in Figure 2 An embodiment, the first pump 2, the second pump 3, the switch 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 cut-off valve group 20 are electrically connected with the controller 21, the controller 21 is electrically connected with a switch button 22, a left slide interface 23 and a right slide interface 24.

[0029] Specifically, Figure 1 191 is the first port of the handle 19, 192 is the second port of the handle 19, 193 is the third port of the handle 19, 194 is the fourth port of the handle 19, 161 is the first port of the load cell 16, 162 is the second port of the load cell 16, 163 is the third port of the load cell 16, 164 is the fourth port of the load cell 16, 201 is the first port of the safety cut-off valve group 20, 202 is the second port of the safety cut-off valve group 20, 203 is the third port of the safety cut-off valve group 20, 204 is the fourth port of the safety cut-off valve group 20, 205 is the fifth port of the safety cut-off valve group 20, Figure 2ST mode switch button 22 in the switch button 22, left handle slide key left slide interface 23 left slide interface 23, right-hand handle slide key right slide interface 24 right slide interface 24, right travel pilot pressure sensor 14 first pressure sensor 14, left travel pilot pressure sensor 15 second pressure sensor 15, arm outside swing pilot pressure sensor 17 third pressure sensor 17, arm inside retract pilot pressure sensor 18 fourth pressure sensor 18, plunger pump 2 first pump 2, plunger pump 3 second pump 3.

[0030] Specifically, the arm outside swing pilot pressure output port 193 of the handle 19 is connected with the 161 port of the pressure block 16, and the arm inside retract pilot pressure output port 194 of the handle 19 is connected with the 162 port of the pressure block 16; the 121 port of the switch valve 12 is connected with the 163 port of the pressure block 16, the 122 port of the switch valve 12 is connected with the 164 port of the pressure block 16, the 123 port of the switch valve 12 is connected with the 120 port of the shuttle valve group 11, the 124 port of the switch valve 12 is connected with the fifth control port 501, the 125 port of the switch valve 12 is connected with the 119 port of the shuttle valve group 11, and the 126 port of the switch valve 12 is connected with the sixth control port 502; when the switch valve 12 is not powered, the 121 port is in communication with the 124 port, and the 122 port is in communication with the 126 port; when the switch valve 12 is powered, the spool is reversed, the 121 port is in communication with the 123 port, and the 122 port is in communication with the 125 port.

[0031] When the switch button 22 is not pressed, it is a normal mode, and the specific process is as follows: The switch valve 12 is not powered; the pilot pressure of the right travel forward pilot pressure output port 133 passes through the 111 port of the shuttle valve group 11, passes through the shuttle valve group 11, and is output from the 115 port of the shuttle valve group 11 to the first control end 901 of the third control valve 9, so that the third control valve 9 is reversed, and at the same time, the first pressure sensor 14 detects the effective pilot pressure, sends an electric signal to the controller 21, and after being processed by the controller 21, sends an electric signal to the first pump 2, and the working oil of the first pump 2 enters the first motor 10, and the first motor 10 advances.

[0032] The pilot pressure of the left forward travel pilot pressure output port 135 passes through the 113 port of the shuttle valve group 11, is output to the third control end 701 of the second control valve 7 through the shuttle valve group 11 from the 117 port of the shuttle valve group 11, and makes the second control valve 7 reverse, while the second pressure sensor 15 detects the effective pilot pressure, sends an electric signal to the controller 21, and after processing by the controller 21, sends an electric signal to the second pump 3, and the working oil of the second pump 3 enters the second motor 8, and the second motor 8 advances; the pilot pressure of the left reverse travel pilot pressure output port 136 passes through the 114 port of the shuttle valve group 11, is output to the fourth control end 702 of the second control valve 7 through the shuttle valve group 11 from the 118 port of the shuttle valve group 11, and makes the second control valve 7 reverse, while the second pressure sensor 15 detects the effective pilot pressure, sends an electric signal to the controller 21, and after processing by the controller 21, sends an electric signal to the second pump 3, and the working oil of the second pump 3 enters the second motor 8, and the second motor 8 advances; alternatively, the first pump 2 and the second pump 3 are both plunger pumps.

[0033] The pilot pressure of the arm outer swing pilot pressure output port 193 of the handle 19 passes through the pressure block 16, is conducted from the 121 port to the 124 port of the switch valve 12, is output to the fifth control end 501 of the first control valve 5, makes the first control valve 5 reverse, while the third pressure sensor 17 detects the effective pilot pressure, sends an electric signal to the controller 21, and after processing by the controller 21, sends an electric signal to the first pump 2, and the working oil of the first pump 2 enters the rod cavity of the oil cylinder 6, and the arm swings out; the pilot pressure of the arm inner swing pilot pressure output port 194 of the handle 19 passes through the pressure block 16, is conducted from the 122 port to the 126 port of the switch valve 12, is output to the sixth control end 502 of the first control valve 5, makes the first control valve 5 reverse, while the fourth pressure sensor 18 detects the effective pilot pressure, sends an electric signal to the controller 21, and after processing by the controller 21, sends an electric signal to the first pump 2, and the working oil of the first pump 2 enters the rodless cavity of the oil cylinder 6, and the arm swings in.

[0034] When the switch button 22 is pressed, it is the straight travel mode, and the specific process is as follows: The switching valve 12 is powered and reversed, the bucket outer swing pilot pressure output port 193 of the handle 19 passes through the pressure block 16, is guided from the 121 port of the switching valve 12 to the 123 port, enters the 120 port of the shuttle valve group 11, passes through the shuttle valve group 11, is output from the 115 port of the shuttle valve group 11 to the first control end 901 of the third control valve 9, and is simultaneously output from the 117 port of the shuttle valve group 11 to the third control end 701 of the second control valve 7, so that the third control valve 9 and the second control valve 7 are simultaneously reversed, and the first motor 10 and the second motor 8 simultaneously advance; the bucket inner swing pilot pressure output port 194 of the handle 19 passes through the pressure block 16, is guided from the 122 port of the switching valve 12 to the 125 port, enters the 119 port of the shuttle valve group 11, is output from the 116 port of the shuttle valve group 11 to the second control end 902 of the third control valve 9, and is simultaneously output from the 118 port of the shuttle valve group 11 to the fourth control end 702 of the second control valve 7, so that the third control valve 9 and the second control valve 7 are simultaneously reversed, and the first motor 10 and the second motor 8 simultaneously retreat; the third pressure sensor 17 or the fourth pressure sensor 18 detects the effective pilot pressure, sends an electric signal to the controller 21, and after processing by the controller 21, sends an electric signal to the first pump 2 and the second pump 3.

[0035] In the straight walking mode, the functions of turning and direction correction can be realized by the following operations: The left handle slide key is slid to the left, the left slide interface 23 outputs an electric signal to the controller 21, and after processing by the controller 21, on the basis of the electric signal of the third pressure sensor 17 or the fourth pressure sensor 18, an electric current signal of increased displacement is sent to the first pump 2, so that the flow output by the first pump 2 to the first motor 10 is increased, and the right walking is accelerated; at the same time, an electric current signal of reduced displacement is sent to the second pump 3, so that the flow output by the second pump 3 to the second motor 8 is reduced, and the left walking is decelerated, and through the speed difference between the left and right walking, the excavator is deflected to the left; the left handle slide key is slid to the right, the right slide interface 24 outputs an electric signal to the controller 21, and after processing by the controller 21, an electric current signal of reduced displacement is sent to the first pump 2, so that the flow output by the first pump 2 to the first motor 10 is reduced, and the right walking is decelerated; at the same time, an electric current signal of increased displacement is sent to the second pump 3, so that the flow output by the second pump 3 to the second motor 8 is increased, and the left walking is accelerated, and through the speed difference between the left and right walking, the excavator is deflected to the right; According to the sliding stroke of the left handle slide key, the electric current signals output by the proportional adjustment controller 21 to the first pump 2 and the second pump 3 are proportional control of the displacements of the first pump 2 and the second pump 3, further control the speed difference between the second motor 8 and the first motor 10, realize proportional control of the deflection radius of the excavator in the straight walking mode, and make the driver more easily turn or correct the direction according to the actual situation of the construction scene.

[0036] In the straight walking mode, the functions of turning and direction correction can be realized by the following operations: When the emergency turning action is needed during the traveling, and the left and right traveling motors are reversely rotated, the driver steps on the traveling pilot valve 13, at this time, any one of the first pressure sensor 14 and the second pressure sensor 15 has a pressure signal, the controller 21 controls the safety cut-off valve group 20 to be powered and commutated, the handle control oil way is cut off, at this time, the turning can be controlled through the traveling pilot valve 13; when the turning is completed, the traveling pilot valve 13 is released, at this time, the first pressure sensor 14 and the second pressure sensor 15 are both without pressure signal, the controller 21 controls the safety cut-off valve group 20 to be powered and reset, and the handle 19 continues to control the traveling of the excavator.

[0037] The excavator system without the single pedal straight traveling function or the handle control straight traveling function is provided with the shuttle valve group 11 and the switching valve 12, and the straight traveling function is realized without increasing the number of the pilot pressure sensors or moving the position of the pilot pressure sensor.

[0038] In the straight traveling mode, the traveling pilot valve 13 can be immediately intervened when the emergency turning working condition is encountered, and the handle control straight traveling oil way is cut off, so that the safety of the turning is ensured. Embodiment two:

[0039] The application provides a working method of an engineering machinery traveling hydraulic system. The conventional mode specifically includes: The switching button 22 is not pressed, so that the switching valve 12 is in a power-off state; The first motor 10 is controlled through the first pump 2 and the third control valve 9, wherein the third control valve 9 is controlled through the traveling pilot valve 13 and the shuttle valve group 11; The first pressure is obtained through the first pressure sensor 14, and the first pump 2 is controlled according to the first pressure; The second motor 8 is controlled through the second pump 3 and the second control valve 7, wherein the second control valve 7 is controlled through the traveling pilot valve 13 and the shuttle valve group 11; The second pressure is obtained through the second pressure sensor 15, and the second pump 3 is controlled according to the second pressure; The oil cylinder 6 is controlled through the first pump 2 and the first control valve 5, wherein the first control valve 5 is controlled through the handle 19 and the switching valve 12; The third pressure is obtained by the third pressure sensor 17, the fourth pressure is obtained by the fourth pressure sensor 18, and the first control valve 5 is controlled according to the third pressure or the fourth pressure; The straight walking mode specifically includes: The switching button 22 is pressed, so that the switching valve 12 is in the power-on state; 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 by the third pressure sensor 17, the fourth pressure is obtained by the fourth pressure sensor 18, and 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 by the left sliding interface 23, the second signal is obtained by the right sliding interface 24, and the first pump 2 and the second pump 3 are further controlled according to the first signal or the second signal; Wherein, when the first pressure sensor 14 or the second pressure sensor 15 has a pressure signal, the safety cut-off valve group 20 is controlled to be power-on and reversed.

[0040] The above is only the preferred embodiment of the present application, it should be noted that for ordinary skilled in the art, without departing from the technical principles of the present application, can also make a number of improvements and modifications, these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. A hydraulic system for traveling of engineering machinery, characterized in that: It comprises 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 end and the third end of the first control valve (5) are both connected to the oil cylinder (6); the second end and the third end 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 end and the third end 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 port of the second control valve (7) and the control port of the third control valve (9) are both connected to the shuttle valve group (11), the control port of the first control valve (5) and the shuttle valve group (11) are both connected to the switching valve (12), the shuttle valve group (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), and the gear pump (4) is connected to the oil tank (1).

2. The hydraulic system for traveling construction 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 construction machinery according to claim 2, characterized in that: The first port, the second port, the third port and the fourth port of the shuttle valve group (11) are all connected to the travel pilot valve (13), and the ninth port and the tenth port of the shuttle valve group (11) are both connected to the switching valve (12); The control port of the third control valve (9) comprises a first control end and a second control end, the first control end being connected to the fifth port of the shuttle valve group (11), and the second control end being connected to the sixth port of the shuttle valve group (11); The control port of the second control valve (7) comprises a third control end and a fourth control end, the third control end being connected to the seventh port of the shuttle valve group (11), and the fourth control end being connected to the eighth port of the shuttle valve group (11).

4. The hydraulic system for traveling construction 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 group (11), the fourth port of the travel pilot valve (13) is connected to the second port of the shuttle valve group (11), the fifth port of the travel pilot valve (13) is connected to the third port of the shuttle valve group (11), and the sixth port of the travel pilot valve (13) is connected to the fourth port of the shuttle valve group (11).

5. The hydraulic system for traveling construction 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 construction machinery according to claim 4, characterized in that: The first control valve (5) includes a fifth control end and a sixth control end, 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 end, the fifth port of the switching valve (12) is connected to the ninth port of the shuttle valve group (11), and the sixth port of the switching valve (12) is connected to the sixth control end.

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

8. The hydraulic system for traveling construction 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 group (20), and the fourth port of the pressure measuring block (16) is connected to the second port of the safety shut-off valve group (20).

9. The hydraulic system for traveling construction machinery according to claim 5, characterized in that: The invention also includes a controller (21), wherein 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 traveling construction machinery, based on the hydraulic system for traveling construction machinery according to claim 9, characterized in that: Includes regular mode and straight walking mode; The conventional mode specifically includes: The switching button (22) is not pressed, so that the switching valve (12) is in a power-off state; 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); obtaining a first pressure through a first pressure sensor (14), and controlling the first pump (2) 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 group (11); obtaining a second pressure through a second pressure sensor (15), and controlling the second pump (3) according to the second pressure; The oil cylinder (6) is controlled by a first pump (2) and a first control valve (5); wherein the first control valve (5) is controlled by a handle (19) and a switching valve (12); Obtaining a third pressure through a third pressure sensor (17), obtaining a fourth pressure through a fourth pressure sensor (18), and controlling the first control valve (5) according to the third pressure or the fourth pressure; The straight-line walking mode specifically includes: Press the switch button (22) to put the switch valve (12) into an energized state; 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); Obtaining a third pressure through a third pressure sensor (17), obtaining a fourth pressure through a fourth pressure sensor (18), and synchronously controlling the first pump (2) and the second pump (3) according to the third pressure or the fourth pressure; A first signal is obtained by sliding the interface (23) to the left, and a second signal is obtained by sliding the interface (24) to the right, and 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 controlled to be energized and switched.

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