Hydraulic system and operation machine

Abstract

The invention relates to the technical field of engineering machinery, and provides a hydraulic system and an operating machine, the hydraulic system is applied to the operating machine, and the hydraulic system comprises a variable pump, a multi-way control valve group and a first switching valve. The variable pump has a constant pressure mode and a load sensitive mode; the multi-path control valve group is used for controlling the operation machinery to act; the first switching valve is provided with a first working position and a second working position, when the first switching valve is switched to the first working position, the variable pump supplies oil to the multi-way control valve set in a constant pressure mode, and when the first switching valve is switched to the second working position, the variable pump supplies oil to the multi-way control valve set in a load sensitive mode. According to the hydraulic system and the operation machine, heating of the system can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of engineering machinery, and in particular to a hydraulic system and an operating machine. Background Art

[0002] Operating machinery, such as tower cranes, use hydraulic components such as pumps and related valves to drive chassis, outriggers or telescopic arms to move. In related technologies, hydraulic components use a constant pressure mode to drive structures such as telescopic arms and outriggers, which can cause serious heating of the system and even affect the service life of the hydraulic components. Summary of the invention

[0003] In view of this, embodiments of the present application hope to provide a hydraulic system and working machine that can reduce system heating.

[0004] In order to achieve the above-mentioned purpose, the technical solution of the embodiment of the present application is implemented as follows:

[0005] On the one hand, an embodiment of the present application discloses a hydraulic system, which is applied to a working machine. The hydraulic system includes:

[0006] A variable displacement pump, wherein the variable displacement pump has a constant pressure mode and a load sensing mode;

[0007] A multi-way control valve group, used to control the operation of the operating machine;

[0008] The first switching valve has a first working position and a second working position. When the first switching valve is switched to the first working position, the variable pump supplies oil to the multi-way control valve group in the constant pressure mode. When the first switching valve is switched to the second working position, the variable pump supplies oil to the multi-way control valve group in the load sensitive mode.

[0009] In one embodiment, the first switching valve has a connecting port, a first working port and a second working port, the variable pump has a first detection port and a second detection port, the hydraulic system has a first detection oil circuit and a second detection oil circuit, the multi-way control valve group has a load signal output port, the first detection port is connected to the connecting port, the first detection oil circuit connects the first detection port and the first working port, the second detection oil circuit connects the load signal output port and the second working port, when the first switching valve is switched to the first working position, the connecting port is connected to the first working port, and the variable pump supplies oil to the multi-way control valve group in the constant pressure mode, when the first switching valve is switched to the second working position, the connecting port is connected to the second working port, and the variable pump can supply oil to the multi-way control valve group in the load sensitive mode according to the load signal output port.

[0010] In one embodiment, the hydraulic system includes a throttle plug, and the throttle plug is arranged on the first detection oil circuit.

[0011] In one embodiment, the multi-way control valve group is a proportional valve.

[0012] In one embodiment, the hydraulic system includes a metering pump, a third working oil circuit, a swing balancing valve and a main arm swing motor, the swing balancing valve is connected to the main arm swing motor, the metering pump is connected to the variable pump, and the third working oil circuit connects the metering pump and the swing balancing valve.

[0013] In one embodiment, the hydraulic system includes a winch motor, a winch balancing valve, a bypass oil circuit and a back pressure valve. The winch balancing valve connects the multi-way control valve group and the winch motor, the bypass oil circuit is respectively connected to the winch motor and the outlet of the back pressure valve, the control port of the back pressure valve is connected to the winch balancing valve, the inlet of the back pressure valve is configured to be able to take in oil, and when the pressure of the winch balancing valve is detected to be greater than a preset value at the control port of the back pressure valve, the inlet of the back pressure valve is connected to the outlet of the back pressure valve.

[0014] In one embodiment, the hydraulic system further includes a hydraulically controlled one-way valve, which is disposed on the bypass oil circuit, wherein the inlet of the hydraulically controlled one-way valve is connected to the outlet of the back pressure valve, and the outlet of the hydraulically controlled one-way valve is connected to the winch motor.

[0015] In one embodiment, the multi-way control valve group has a first main arm oil port, a second main arm oil port, a first auxiliary arm oil port and a second auxiliary arm oil port, and the hydraulic system includes:

[0016] The main arm telescopic cylinder has a main rod chamber and a main rodless chamber;

[0017] The auxiliary arm telescopic oil cylinder has an auxiliary rod chamber and an auxiliary rodless chamber;

[0018] a fourth working oil circuit and a fifth working oil circuit, wherein the fourth working oil circuit is connected to the main rodless chamber and the first main arm oil port, and the fifth working oil circuit is connected to the main rod chamber and the second main arm oil port;

[0019] a first oil circuit, a second oil circuit and a third oil circuit, wherein the first oil circuit can selectively connect to the secondary rod chamber or the secondary rodless chamber, the second oil circuit connects to the main rod chamber, and the third oil circuit connects to the main rodless chamber;

[0020] The sixth working oil circuit and the seventh working oil circuit, the sixth working oil circuit connects the third oil circuit and the first jib oil port, one end of the seventh working oil circuit connects the second jib oil port, and the other end of the seventh working oil circuit can selectively connect the first oil circuit or the second oil circuit.

[0021] In one embodiment, the hydraulic system includes a second switching valve, the second switching valve having a third working position and a fourth working position. When the second switching valve is switched to the third working position, the sixth working oil circuit is cut off from the third oil circuit, and the seventh working oil circuit is connected to the first oil circuit. When the second switching valve is switched to the fourth working position, the sixth working oil circuit is connected to the third oil circuit, and the seventh working oil circuit is connected to the second oil circuit.

[0022] Another aspect of the embodiments of the present application discloses a working machine, comprising the hydraulic system in any one of the above embodiments.

[0023] The embodiment of the present application discloses a hydraulic system and a working machine. After the first switching valve is switched to the first working position, the variable pump can supply oil to the multi-way control valve group in a constant pressure mode in a quantitative manner. On the one hand, it can reduce the speed fluctuation caused by pressure fluctuations when the working machine is in motion, and can reduce bumps and shaking, which is conducive to operations on complex terrain or uneven sites; on the other hand, the oil supply in the constant pressure mode has a fast response and a stable flow rate during operation, and can achieve good micro-mobility. When the first switching valve is switched to the second working position, the variable pump can supply oil to the multi-way control valve group in a load-sensitive mode. The variable pump can provide the required flow rate based on the load feedback of the multi-way control valve group according to the working machine action without excess power consumption. In this way, the heating of the system can be reduced to increase the service life of each hydraulic component. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A partial hydraulic principle diagram of the hydraulic system provided in the embodiment of the present application;

[0025] Figure 2 A partial hydraulic principle diagram of a hydraulic system provided in another embodiment of the present application;

[0026] Figure 3 A partial hydraulic principle diagram of a hydraulic system provided in yet another embodiment of the present application;

[0027] Figure 4 for Figure 1 A hydraulic principle diagram of a variable pump, a first switching valve, a first detection oil circuit, a main delivery oil circuit, a first detection oil circuit, a second detection oil circuit, a throttle plug and a first overflow valve.

[0028] Description of Reference Numerals

[0029] 100. Hydraulic system; 1. Variable displacement pump; 1a. First detection port; 1b. Oil supply port; 1c. Second detection port; 2. Multi-way control valve group; 21. First multi-way control valve; 21a. First load signal output port; 22. Second multi-way control valve; 22a. Second load signal output port; 22b. First hoisting oil port; 22c. Second hoisting oil port; 22d. First main arm oil port; 22e. Second main arm oil port; 22f. First auxiliary arm oil port; 2 2g, second auxiliary arm oil port; 3, first switching valve; 3a, connecting port; 3b, first working port; 3c, second working port; 31, first working position; 32, second working position; 4, first detection oil circuit; 5, second detection oil circuit; 6, connecting oil circuit; 7, throttle plug; 8, first overflow valve; 9, first overflow oil circuit; 101, main delivery oil circuit; 102, third switching valve; 102a, oil inlet; 102b, oil return port; 102c, first output port; 102d, second output port; 103, first oil delivery circuit; 104, second oil delivery circuit; 105, winch motor; 105a, lifting oil port; 105b, lowering oil port; 106, winch balance valve; 106a, first oil port; 106b, second oil port; 106c, third oil port; 107, bypass oil circuit; 108, back pressure valve; 109, hydraulically controlled one-way valve; A, first winch working oil circuit; B, second winch working oil circuit; C, Dosing pump; D, third working oil circuit; E, slewing balance valve; F, main arm slewing motor; G, main arm telescopic cylinder; H, auxiliary arm telescopic cylinder; J, fourth working oil circuit; K, fifth working oil circuit; L, sixth working oil circuit; M, seventh working oil circuit; N, first oil circuit; P, second oil circuit; Q, third oil circuit; R, second switching valve; R1, third working position; R2, fourth working position; T, oil tank; W, first return oil filter; Y, second return oil filter. DETAILED DESCRIPTION

[0030] It should be noted that, in the absence of conflict, the embodiments and technical features in the embodiments of the present application can be combined with each other, and the detailed description in the specific implementation method should be understood as an explanation of the purpose of the present application and should not be regarded as an improper limitation on the present application.

[0031] The present application is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The descriptions of "first", "second", etc. in the embodiments of the present application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly including at least one feature. In the description of the embodiments of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically limited.

[0032] In order to better understand the hydraulic system 100 provided in the present application, the working machine will be described first.

[0033] On one hand, an embodiment of the present application provides a working machine, comprising a hydraulic system 100 in any one of the following embodiments.

[0034] Exemplarily, the working machine includes an outrigger assembly, a chassis and a telescopic arm, wherein the outrigger assembly and the telescopic arm are both arranged on the chassis, and the telescopic arm includes a main arm and a secondary arm, wherein the secondary arm is rotatably arranged on the main arm. The hydraulic system 100 is used to drive the outrigger assembly, the chassis and the telescopic arm to perform operations. The outrigger assembly includes an outrigger and a swing leg, wherein the swing leg is rotatably connected to the chassis, and the outrigger is arranged on the swing leg. The hydraulic system 100 can control the extension and retraction of the outrigger, the opening or retraction of the swing leg, the travel motor in the chassis, and the extension and retraction and amplitude change of the telescopic arm, etc.

[0035] Another aspect of the present application embodiment provides a hydraulic system 100, see Figures 1 to 4 The hydraulic system 100 includes a variable pump 1, a multi-way control valve group 2 and a first switching valve 3. The variable pump 1 has a constant pressure mode and a load sensitive mode. The multi-way control valve group 2 is used to control the operation of the working machine. The first switching valve 3 has a first working position 31 and a second working position 32. When the first switching valve 3 is switched to the first working position 31, the variable pump 1 supplies oil to the multi-way control valve group 2 in a constant pressure mode. When the first switching valve 3 is switched to the second working position 32, the variable pump 1 supplies oil to the multi-way control valve group 2 in a load sensitive mode.

[0036] The hydraulic system 100 provided in the present application can make the variable pump 1 supply oil to the multi-way control valve group 2 in a constant pressure mode in a quantitative manner after the first switching valve 3 is switched to the first working position 31. On the one hand, it can reduce the speed fluctuation caused by pressure fluctuation during the operation of the operating machine, reduce bumps and shaking, and is conducive to operations on complex terrain or uneven sites; on the other hand, the oil supply in the constant pressure mode has a fast response and stable flow during operation, and can achieve good micro-mobility. When the first switching valve 3 is switched to the second working position 32, the variable pump 1 can supply oil to the multi-way control valve group 2 in a load-sensitive mode. The variable pump 1 can provide the required flow based on the load feedback of the multi-way control valve group 2 according to the operation of the operating machine without excess power consumption. In this way, the heating of the system can be reduced to increase the service life of each hydraulic component.

[0037] The operating machine provided in the present application, based on the advantages of the above-mentioned hydraulic system 100, also has the advantages of less heat generation and faster response.

[0038] For example, the working machine may be a tower crane or a crane, etc.

[0039] Exemplarily, in one embodiment, the variable displacement pump 1 may be a variable displacement piston pump.

[0040] In one embodiment, please refer to Figure 1 and Figure 4 The first switching valve 3 has a connecting port 3a, a first working port 3b and a second working port 3c, the variable pump 1 has a first detection port 1a and a second detection port 1c, the hydraulic system 100 has a first detection oil circuit 4 and a second detection oil circuit 5, the multi-way control valve group 2 has a load signal output port, the first detection port 1a is connected to the connecting port 3a, the first detection oil circuit 4 is connected to the first detection port 1a and the first working port 3b, the second detection oil circuit 5 is connected to the load signal output port and the second working port 3c, when the first switching valve 3 is switched to the first working position 31, the connecting port 3a is connected to the first working port 3b, and the variable pump 1 supplies oil to the multi-way control valve group 2 in a constant pressure mode, and when the first switching valve 3 is switched to the second working position 32, the connecting port 3a is connected to the second working port 3c, and the variable pump 1 can supply oil to the multi-way control valve group 2 in a load sensitive mode according to the load signal output port.

[0041] That is to say, when the first switching valve 3 is switched to the first working position 31, the first detection port 1a of the variable pump 1 is connected to the second detection port 1c of the first switching valve 3 through the first detection oil circuit 4, and the load demand of the multi-way control valve group 2 is not obtained. At this time, the variable pump 1 will supply oil to the multi-way control valve group 2 in a constant pressure mode. In this way, the output of the stable oil supply method enables the operating machine to respond quickly when in action, with less lag, so as to achieve better micro-mobility. When the first switching valve 3 is switched to the second working position 32, the first detection port 1a of the variable pump 1 can be connected to the load signal output port through the second detection oil circuit 5 and the first switching valve 3 to obtain the load demand of the multi-way control valve group 2, and then the variable pump 1 will provide the required flow according to the load feedback, without excess power consumption, and the system will generate less heat.

[0042] For example, in one embodiment, please refer to Figure 1 The multi-way control valve group 2 includes a first multi-way control valve 21 and a second multi-way control valve 22. The first multi-way control valve 21 is used to control the movement of the chassis and the leg assembly, and the second multi-way control valve 22 is used to control the movement of the telescopic arm. The first multi-way control valve 21 has a first load signal output port 21a, and the second multi-way control valve 22 has a second load signal output port 22a. The second detection oil circuit 5 is respectively connected to the first load signal output port 21a and the second load signal output port 22a.

[0043] For example, in one embodiment, please refer to Figure 1 The hydraulic system 100 includes a communication oil path 6 , and the communication oil path 6 connects the first detection port 1 a and the communication port 3 a .

[0044] In one embodiment, please refer to Figure 1 The hydraulic system 100 includes a throttle plug 7 , which is arranged on the first detection oil circuit 4 .

[0045] Exemplarily, the throttle plug 7 may be disposed in the first detection oil passage 4 close to the first working port 3 b , that is, the hydraulic oil flowing out of the first working port 3 b first passes through the throttle plug 7 .

[0046] Here, by providing the throttle plug 7 on the first detection oil path 4, the flow rate of the hydraulic oil output to the first detection oil path 4 can be controlled, thereby reducing damage to the variable pump 1 and facilitating identification.

[0047] Exemplarily, in one embodiment, the aperture of the throttle plug 7 may be 0.8 mm.

[0048] In one embodiment, please refer to Figure 1 The first switching valve 3 can be a two-position three-way solenoid valve, and its second working position 32 is normally open, that is, the connecting port 3a and the second working port 3c are in a normally connected state. In this way, the operating machine can supply oil to the multi-way control valve group 2 in a load-sensitive mode in most scenarios. When the first switching valve 3 is energized, the connecting port 3a is connected to the first working port 3b, and the hydraulic oil can control the flow through the throttle plug 7 to achieve a constant pressure mode.

[0049] For example, in one embodiment, please refer to Figure 1 The hydraulic system 100 includes a first overflow valve 8 and a first overflow oil circuit 9. The first overflow oil circuit 9 connects the connecting oil circuit 6 and the oil tank T. The first overflow valve 8 is arranged on the first overflow oil circuit 9, and its outlet is connected to the oil tank T. In this way, when the pressure in the connecting oil circuit 6 is greater than the opening pressure of the first overflow valve, the first overflow valve 8 will open, so that the inlet of the first overflow valve 8 is connected to its outlet. In this way, the excess hydraulic oil in the connecting oil circuit 6 can flow to the oil tank T through the first overflow oil circuit 9 and the first overflow valve 8. On the one hand, the hydraulic oil pressure of the connecting oil circuit 6 can be relieved to limit the maximum pressure in the connecting oil circuit 6, which is highly safe; on the other hand, the oil tank T can be replenished with oil through the first overflow oil circuit 9.

[0050] In one embodiment, the multi-way control valve group 2 is a proportional valve.

[0051] For example, see Figure 1 , the first multi-way control valve 21 and the second multi-way control valve 22 can both be proportional valves. The first multi-way control valve 21 can have six routes, the first route is used to control the left travel, the second route is used to control the swing, horizontal extension and vertical extension of the front left leg, the third route controls the swing, horizontal extension and vertical extension of the front right leg, the fourth route controls the swing, horizontal extension and vertical extension of the rear left leg, the fifth route controls the swing, horizontal extension and vertical extension of the rear right leg, and the sixth route controls the right travel. The second multi-way control valve 22 can have five routes, the first route is used to control the extension and retraction of the auxiliary arm, the second route is used to control the extension and retraction of the main arm, the third route is used to control the amplitude change of the main arm, the fourth route is used to winch to lift or lower heavy objects, and the fifth route is used to control the amplitude change of the auxiliary arm.

[0052] In this way, by using a proportional valve as the multi-way control valve group 2, on the one hand, smooth and stepless changes can be achieved to accurately control the movements of the outrigger assembly, chassis and telescopic arm, etc.; on the other hand, the proportional valve has the characteristic of fast response, and can cooperate with the constant pressure mode to quickly respond and realize the movements of the outrigger assembly, chassis and telescopic arm, etc., and can achieve better micro-motion to meet precise positioning, making the operating machinery more efficient and safer; on another hand, the proportional valve can accurately control the output of hydraulic oil to reduce energy consumption, thereby saving costs and improving efficiency.

[0053] Exemplarily, in one embodiment, the proportional valve may be an electric proportional valve, which controls the displacement of the variable pump 1 by electric proportionality.

[0054] For example, in one embodiment, please refer to Figure 1 The hydraulic system 100 includes a main oil delivery circuit 101, a third switching valve 102, a first oil delivery circuit 103 and a second oil delivery circuit 104. The variable pump 1 has an oil supply port 1b. The third switching valve 102 includes an oil inlet 102a, an oil return port 102b, a first output port 102c and a second output port 102d. The main oil delivery circuit 101 is connected to the oil supply port 1b and the oil inlet 102a, the oil return port 102b is connected to the oil tank T, and the first oil delivery circuit 103 is connected to the first output port 10 2c and the inlet of the first multi-way control valve 21, the second oil delivery circuit 104 is connected to the second output port 102d and the inlet of the second multi-way control valve 22, the third switching valve 102 has at least two functional positions, when switched to one of the functional positions, the oil inlet 102a is connected to one output port, and the oil return port 102b is connected to the second output port 102d, when switched to the other functional position, the oil inlet 102a is connected to the two output ports, and the oil return port 102b is connected to the first output port 102c.

[0055] For example, in one embodiment, please refer to Figure 1 The hydraulic system 100 includes a first return oil filter W, which is arranged on the main oil delivery circuit 101 to reduce hydraulic oil pollution.

[0056] In one embodiment, please refer to Figure 2 The hydraulic system 100 includes a hoisting motor 105, a hoisting balance valve 106, a bypass oil circuit 107 and a back pressure valve 108. The hoisting balance valve 106 is connected to the multi-way control valve group 2 and communicates with the hoisting motor 105. The bypass oil circuit 107 is respectively connected to the hoisting motor 105 and the outlet of the back pressure valve 108. The control port of the back pressure valve 108 is connected to the hoisting balance valve 106. The inlet of the back pressure valve 108 is configured to be able to take in oil. When the pressure of the hoisting balance valve 106 is detected to be greater than a preset value at the control port of the back pressure valve 108, the inlet of the back pressure valve 108 is connected to the outlet of the back pressure valve 108.

[0057] Exemplarily, the second multi-way control valve 22 has a first hoisting oil port 22b and a second hoisting oil port 22c, the hoisting balance valve 106 has a first oil port 106a, a second oil port 106b and a third oil port 106c, the hydraulic system 100 includes a first hoisting working oil circuit A and a second hoisting working oil circuit B, the hoisting motor 105 has a lifting oil port 105a and a lowering oil port 105b, the first hoisting working oil circuit A connects the first oil port 106a and the first hoisting oil port 22b, the second oil port 106b connects the lifting oil port 105a, the second hoisting working oil circuit B connects the second hoisting oil port 22c and the lowering oil port 105b, the third oil port 106c is connected to the control port of the back pressure valve 108, and is used to detect the pressure of the hoisting balance valve 106, the bypass oil circuit 107 can connect the second hoisting working oil circuit and the outlet of the back pressure valve 108, and the inlet of the back pressure valve 108 can be connected to the oil tank T through the oil circuit.

[0058] In this way, when the first hoisting oil port 22b is configured as an oil inlet and the second hoisting oil port 22c is configured as an oil return, the hydraulic oil can enter the first oil port 106a through the first hoisting working oil circuit A and then enter the lifting oil port 105a from the second oil port 106b through the hoisting balance valve 106, the hoisting motor 105 rotates to lift the heavy object, and the hydraulic oil can enter the second hoisting oil port 22c from the lowering oil port 105b through the second hoisting working oil circuit B for oil return. When the first hoisting oil port 22b is configured as an oil return and the second hoisting oil port 22c is configured as an oil inlet, the hydraulic oil can enter the lowering oil port 105b through the second hoisting working oil circuit B, the hoisting motor 105 rotates to lower the heavy object, and the hydraulic oil can enter the second oil port 106b from the lifting oil port 105a and then enter the first hoisting oil port 22b through the first hoisting working oil circuit A through the hoisting balance valve 106 for oil return. When the balancing valve fails, the hoisting motor 105 will rotate at a high speed and exceed the rated speed of the hoisting motor 105. If the lower oil port 105b is not replenished with hydraulic oil, the hoisting motor 105 will experience high-speed dry grinding and cause damage to the hoisting motor 105. Therefore, the present application sets a bypass oil port. When the hoisting balancing valve 106 fails, the control port of the back pressure valve 108 detects an increase in pressure in the hoisting balancing valve 106. When the pressure increases to exceed a preset value, the outlet of the back pressure valve 108 and its inlet will be connected. In this way, the hydraulic oil can be replenished to the lower oil port 105b through the bypass oil circuit 107 to reduce the speed of the hoisting motor 105.

[0059] Thus, by providing the back pressure valve 108 and the bypass oil circuit 107, when the hoisting balance valve 106 fails, the hoisting motor 105 can be supplemented with oil to reduce the rotation speed of the hoisting motor 105, thereby reducing damage to the hoisting motor 105 and increasing its service life.

[0060] In one embodiment, the preset value is 5 bar. Thus, when the pressure of the hoisting balance valve 106 exceeds 5 bar, the back pressure valve 108 can replenish oil to the hoisting motor 105 through the bypass oil circuit 107 to reduce the rotation speed of the hoisting motor 105 .

[0061] In one embodiment, please refer to Figure 2 The hydraulic system 100 also includes a hydraulically controlled one-way valve 109 , which is disposed on the bypass oil circuit 107 , the inlet of the hydraulically controlled one-way valve 109 is connected to the outlet of the back pressure valve 108 , and the outlet of the hydraulically controlled one-way valve 109 is connected to the winch motor 105 .

[0062] For example, the hydraulically controlled one-way valve 109 can be arranged at the outlet of the bypass oil circuit 107 near the back pressure valve 108. When the hoisting balance valve 106 is not invalid, the hydraulically controlled one-way valve 109 is closed to prevent the hydraulic oil from entering the back pressure valve 108 from the bypass oil circuit 107. When the hoisting balance valve 106 is invalid, the hydraulically controlled one-way valve 109 is opened, and the hydraulic oil can be quickly replenished, thereby reducing the damage to the hoisting motor 105, thus improving the working stability and service life of the hoisting motor 105.

[0063] In one embodiment, please refer to Figure 1 The hydraulic system 100 includes a metering pump C, a third working oil circuit D, a swing balancing valve E and a main arm swing motor F. The swing balancing valve E is connected to the main arm swing motor F, the metering pump C is connected to the variable pump 1, and the third working oil circuit D is connected to the metering pump C and the swing balancing valve E.

[0064] For example, the metering pump C may be a metering gear pump. The third working oil circuit D is connected to the metering pump C and the swing balance valve E, and the swing balance valve E is connected to the main arm swing motor F to drive the main arm to rotate.

[0065] Here, the hydraulic oil output by the metering pump C can be supplied to the main arm slewing motor F through the third working oil circuit D via the slewing balance valve E, so as to realize the centering of the main arm and reduce the inclined pulling of the main arm by the wire rope.

[0066] For example, in one embodiment, please refer to Figure 1 The hydraulic system 100 includes a second return oil filter Y, which is arranged on the third working oil circuit D to reduce hydraulic oil pollution.

[0067] In one embodiment, please refer to Figure 1 and Figure 3, the second multi-way control valve 22 has a first main arm oil port 22d, a second main arm oil port 22e, a first auxiliary arm oil port 22f and a second auxiliary arm oil port 22g, and the hydraulic system 100 includes a main arm telescopic cylinder G, an auxiliary arm telescopic cylinder H, a fourth working oil circuit J, a fifth working oil circuit K, a first oil circuit N, a second oil circuit P, a third oil circuit Q, a sixth working oil circuit L and a seventh working oil circuit M. The main arm telescopic cylinder G has a main rodless chamber and a main rodless chamber. The auxiliary arm telescopic cylinder H has a secondary rod chamber and a secondary rodless chamber. The fourth working oil circuit J and the fifth working oil circuit K, the fourth working oil circuit J connects the main rodless chamber and the first main arm oil port 22d, and the fifth working oil circuit K connects the main rod chamber and the second main arm oil port 22e. The first oil circuit N, the second oil circuit P and the third oil circuit Q, the first oil circuit N can selectively connect the secondary rod chamber or the secondary rodless chamber, the second oil circuit P connects the main rod chamber, and the third oil circuit Q connects the main rodless chamber. The sixth working oil circuit L and the seventh working oil circuit M, the sixth working oil circuit L connects the third oil circuit Q and the first auxiliary arm oil port 22f, one end of the seventh working oil circuit M connects the second auxiliary arm oil port 22g, and the other end of the seventh working oil circuit M can selectively connect the first oil circuit N or the second oil circuit P.

[0068] Here, the fourth working oil circuit J is connected to the main rodless chamber, and the fifth working oil circuit K is connected to the main rod chamber and the second main arm oil port 22e. In this way, the hydraulic oil can enter the main rodless chamber from the first main arm oil port 22d through the fourth working oil circuit J, and the hydraulic oil in the main rod chamber can flow back to the second main arm oil port 22e through the fifth working oil circuit K to realize the extension action of the main arm telescopic cylinder G. Of course, the hydraulic oil can also enter the main rod chamber from the second main arm oil port 22e through the fifth working oil circuit K, and the hydraulic oil in the main rodless chamber can flow back to the first main arm oil port 22d through the fourth working oil circuit J to realize the retraction of the main arm telescopic cylinder G. The first oil circuit N can selectively connect to the secondary rod chamber or the secondary rodless chamber, one end of the seventh working oil circuit M is connected to the second auxiliary arm oil port 22g, and the other end can selectively connect to the first oil circuit N or the second oil circuit P, and the sixth working oil circuit L is connected to the third oil circuit Q, that is, the sixth working oil circuit L can be selectively connected or disconnected with the third oil circuit Q. In this way, when it is necessary to speed up the extension of the main arm, the sixth working oil circuit L can be connected to the third oil circuit Q, so that the hydraulic oil in the sixth working oil circuit L and the third oil circuit Q can cooperate with the hydraulic oil in the fourth working oil circuit J to flow into the main rodless chamber to accelerate the extension of the main arm telescopic cylinder G; when it is necessary to accelerate the retraction of the main arm, the seventh working oil circuit M can be connected to the second oil circuit P, so that the hydraulic oil in the seventh working oil circuit M and the second oil circuit P can cooperate with the hydraulic oil in the fifth working oil circuit K to flow into the main rod chamber to accelerate the retraction of the main arm telescopic cylinder G. When the auxiliary arm needs to be extended, the seventh working oil circuit M can be connected with the first oil circuit N, and the first oil circuit N can be connected with the auxiliary rodless chamber to realize the extension of the auxiliary arm telescopic cylinder H; when the auxiliary arm is retracted, the seventh working oil circuit M can be connected with the first oil circuit N, and the first oil circuit N can be connected with the auxiliary rod chamber to realize the retraction of the auxiliary arm telescopic cylinder H. In this way, when the main arm telescopic cylinder G is extended, the flow of the auxiliary arm telescopic cylinder H can be merged into the main arm telescopic cylinder G to realize rapid action and high telescopic efficiency.

[0069] In one embodiment, the hydraulic system 100 includes a second switching valve R, and the second switching valve R has a third working position R1 and a fourth working position R2. When the second switching valve R is switched to the third working position R1, the sixth working oil circuit L and the third oil circuit Q are cut off, and the seventh working oil circuit M is connected to the first oil circuit N. When the second switching valve R is switched to the fourth working position R2, the sixth working oil circuit L is connected to the third oil circuit Q, and the seventh working oil circuit M is connected to the second oil circuit P.

[0070] Exemplarily, when it is necessary to speed up the extension of the main arm, the fourth working oil circuit J and the sixth working oil circuit L can be configured as oil supply circuits, and the fifth working oil circuit K and the seventh working oil circuit M can be configured as oil return circuits. At this time, the second switching valve R can be switched to the fourth working position R2, so that the sixth working oil circuit L can be connected with the third oil circuit Q, and the seventh working oil circuit M can be connected with the second oil circuit P. In this way, part of the hydraulic oil in the sixth working oil circuit L and the third oil circuit Q can be combined with the hydraulic oil in the fourth working oil circuit J to flow into the main rodless chamber to accelerate the extension of the main arm telescopic cylinder G, and the hydraulic oil in the main rod chamber can be returned through the fifth working oil circuit K, the second oil circuit P and the seventh working oil circuit M; When it is necessary to speed up the retraction of the main arm, the fourth working oil circuit J and the sixth working oil circuit L can be configured as the return oil circuit, and the fifth working oil circuit K and the seventh working oil circuit M can be configured as the supply oil circuit. At this time, the second switching valve R can be switched to the fourth working position R2, so that the seventh working oil circuit M is connected with the second oil circuit P, and the sixth working oil circuit L can be connected with the third oil circuit Q. In this way, part of the hydraulic oil in the seventh working oil circuit M and the second oil circuit P can cooperate with the hydraulic oil in the fifth working oil circuit K to flow into the main rod chamber to accelerate the retraction of the main arm telescopic cylinder G, and the hydraulic oil in the main rodless chamber can flow back through the fourth working oil circuit J, the sixth working oil circuit L and the third oil circuit Q.

[0071] When the main arm telescopic cylinder G is in place, the second switching valve R can be switched to the third working position R1, so that the sixth working oil circuit L and the third oil circuit Q are cut off, and the seventh working oil circuit M is connected to the first oil circuit N. In this way, the main arm telescopic cylinder G is supplied with oil and returned with oil through the fourth working oil circuit J and the fifth working oil circuit K to realize the telescopic action, and the auxiliary arm telescopic cylinder H can be selectively connected to the auxiliary rod chamber and the auxiliary rodless chamber through the first oil circuit N to realize the telescopic work.

[0072] The above is only a preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. All modifications, equivalent substitutions, improvements, etc. within the spirit and principles of the present application are included in the protection scope of the present application.

Claims

1. A hydraulic system, applied to an operating machine, characterized in that: The hydraulic system comprises: A variable displacement pump, wherein the variable displacement pump has a constant pressure mode and a load sensing mode; A multi-way control valve group, used to control the operation of the operating machine; The first switching valve has a first working position and a second working position. When the first switching valve is switched to the first working position, the variable pump supplies oil to the multi-way control valve group in the constant pressure mode. When the first switching valve is switched to the second working position, the variable pump supplies oil to the multi-way control valve group in the load sensitive mode.

2. The hydraulic system according to claim 1, characterized in that: The first switching valve has a connecting port, a first working port and a second working port, the variable pump has a first detection port and a second detection port, the hydraulic system has a first detection oil circuit and a second detection oil circuit, the multi-way control valve group has a load signal output port, the first detection port is connected to the connecting port, the first detection oil circuit is connected to the first detection port and the first working port, the second detection oil circuit is connected to the load signal output port and the second working port, when the first switching valve is switched to the first working position, the connecting port is connected to the first working port, the variable pump supplies oil to the multi-way control valve group in the constant pressure mode, when the first switching valve is switched to the second working position, the connecting port is connected to the second working port, and the variable pump can supply oil to the multi-way control valve group in the load sensitive mode according to the load signal output port.

3. The hydraulic system according to claim 2, characterized in that: The hydraulic system includes a throttle plug, and the throttle plug is arranged on the first detection oil circuit.

4. The hydraulic system according to claim 1, characterized in that: The multi-way control valve group is a proportional valve.

5. The hydraulic system according to claim 1, characterized in that: The hydraulic system includes a metering pump, a third working oil circuit, a swing balancing valve and a main arm swing motor. The swing balancing valve is connected to the main arm swing motor, the metering pump is connected to the variable pump, and the third working oil circuit connects the metering pump and the swing balancing valve.

6. The hydraulic system according to claim 1, characterized in that: The hydraulic system includes a winch motor, a winch balancing valve, a bypass oil circuit and a back-pressure valve. The winch balancing valve connects the multi-way control valve group and the winch motor. The bypass oil circuit is respectively connected to the winch motor and the outlet of the back-pressure valve. The control port of the back-pressure valve is connected to the winch balancing valve. The inlet of the back-pressure valve is configured to be able to take in oil. When the pressure of the winch balancing valve is detected to be greater than a preset value at the control port of the back-pressure valve, the inlet of the back-pressure valve is connected to the outlet of the back-pressure valve.

7. The hydraulic system according to claim 6, characterized in that: The hydraulic system further comprises a hydraulically controlled one-way valve, which is arranged on the bypass oil circuit, wherein the inlet of the hydraulically controlled one-way valve is connected to the outlet of the back pressure valve, and the outlet of the hydraulically controlled one-way valve is connected to the winch motor.

8. The hydraulic system according to claim 1, characterized in that: The multi-way control valve group has a first main arm oil port, a second main arm oil port, a first auxiliary arm oil port and a second auxiliary arm oil port, and the hydraulic system includes: The main arm telescopic cylinder has a main rod chamber and a main rodless chamber; The auxiliary arm telescopic oil cylinder has an auxiliary rod chamber and an auxiliary rodless chamber; a fourth working oil circuit and a fifth working oil circuit, wherein the fourth working oil circuit is connected to the main rodless chamber and the first main arm oil port, and the fifth working oil circuit is connected to the main rod chamber and the second main arm oil port; a first oil circuit, a second oil circuit and a third oil circuit, wherein the first oil circuit can selectively connect to the secondary rod chamber or the secondary rodless chamber, the second oil circuit connects to the main rod chamber, and the third oil circuit connects to the main rodless chamber; The sixth working oil circuit and the seventh working oil circuit, the sixth working oil circuit connects the third oil circuit and the first jib oil port, one end of the seventh working oil circuit connects the second jib oil port, and the other end of the seventh working oil circuit can selectively connect the first oil circuit or the second oil circuit.

9. The hydraulic system according to claim 8, characterized in that: The hydraulic system includes a second switching valve, which has a third working position and a fourth working position. When the second switching valve is switched to the third working position, the sixth working oil circuit is cut off from the third oil circuit, and the seventh working oil circuit is connected to the first oil circuit. When the second switching valve is switched to the fourth working position, the sixth working oil circuit is connected to the third oil circuit, and the seventh working oil circuit is connected to the second oil circuit.

10. A working machine, characterized in that: A hydraulic system comprising any one of claims 1 to 9.

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