CN104235102A - On-board hydraulic system and construction machinery - Google Patents

Abstract

The invention discloses a boarding hydraulic system and engineering machinery, wherein the boarding hydraulic system comprises a main oil inlet oil way (4), a main oil return oil way (5) and at least two hydraulic actuating elements, the at least two hydraulic actuating elements are respectively connected with reversing control loops, and each reversing control loop comprises: a first directional valve (1), a first and a second two-way pressure compensation valve (7, 8); the first two-way pressure compensation valve feedback oil ports (71) in the at least two reversing control loops are connected with each other, the second two-way pressure compensation valve feedback oil ports (81) in the at least two reversing control loops are connected with each other, the first two-way pressure compensation valve feedback oil ports (71) and the second two-way pressure compensation valve feedback oil ports (81) in each reversing control loop are connected with each other through respective hydraulic control feedback branch oil paths, and the hydraulic control feedback branch oil paths are connected with each other.

Description

On-board hydraulic system and construction machinery

technical field

The invention relates to the field of construction machinery, in particular to a hydraulic system for boarding and construction machinery.

Background technique

Aerial work equipment is different from general construction machinery. It is characterized by low operating frequency and small load, but requires high safety and reliability. The hydraulic system of the aerial work equipment is composed of the upper hydraulic system and the lower hydraulic system. Among them, the boarding hydraulic system usually includes three basic systems: luffing system, telescopic system and slewing system. The hydraulic oil source of the boarding hydraulic system can supply hydraulic oil to the respective actuators in the luffing system, the telescopic system and the slewing system, so as to realize the predetermined action of boarding.

The main defect of the boarding hydraulic system in the prior art is that when the boarding hydraulic system has compound actions, the flow of hydraulic oil in the actuators in the luffing system, the telescopic system and the slewing system is unevenly distributed. The flow to the light load is more, the flow to the heavy load is less, and the linkage of each actuator is poor.

In view of this, it is necessary to provide a new type of hydraulic system on the vehicle to overcome or alleviate the above-mentioned defects.

Contents of the invention

One object of the present invention is to provide a boarding hydraulic system, which can ensure the linkage when multiple hydraulic actuators move, that is, each hydraulic actuator can get the same flow distribution, so that the flow distribution has nothing to do with the load .

Another object of the present invention is to provide a construction machine that uses the boarding hydraulic system provided by the present invention.

In order to achieve the above object, the present invention provides a hydraulic system on board, comprising a main oil inlet oil circuit, a main oil return oil circuit and at least two hydraulic actuators, each of which is connected to a reversing control circuit, wherein each of the reversing control circuits includes: a first reversing valve, which includes first to fourth working oil ports, and the oil inlet of the first reversing valve is connected to the main oil inlet circuit , the oil return port is connected to the main oil return circuit, wherein the second working oil port and the third working oil port are respectively connected to the corresponding hydraulic pressure via the first working oil circuit and the second working oil circuit. The executive element, the first reversing valve can at least be switched to the first and second working states, wherein in the first working state, the oil inlet is connected to the first working oil port, and the oil return port is connected to the second working oil port. The three working oil ports are connected, and the oil inlet and the oil return port are cut off from each other and both are cut off from the second working oil port and the fourth working oil port; in the second working state, the oil inlet and the first The four working oil ports are connected, the oil return port is connected to the second working oil port, and the oil inlet and the oil return port are cut off from each other and both are cut off from the first working oil port and the third working oil port ; first and second two-way pressure compensation valves, the input oil port of the first two-way pressure compensation valve is connected to the first working oil port and the hydraulic control chamber port of the first two-way pressure compensation valve, and The output oil port is connected to the first working oil circuit; the input oil port of the second two-way pressure compensation valve is connected to the fourth working oil port and the hydraulic control chamber port of the second two-way pressure compensation valve, And the output oil port is connected to the second working oil circuit; the first and second two-way pressure compensation valves also include feedback oil ports connected to their respective spring chambers, wherein the first and second two-way The pressure compensating valve can make the respective input oil port and the respective feedback oil port conduct simultaneously under the state that the respective input oil port is connected with the respective output oil port; wherein, at least two of the reversing The feedback oil ports of the first two-way pressure compensation valve in the control circuit are connected to each other, the feedback oil ports of the second two-way pressure compensation valve in at least two of the reversing control circuits are connected to each other, and each of the reversing The first two-way pressure compensation valve feedback oil port and the second two-way pressure compensation valve feedback oil port in the control circuit are connected to each other through their respective hydraulic control feedback branch oil passages, and each of the hydraulic control feedback branch oil passages is connected to each other. connect.

Preferably, each of the hydraulic control feedback branch oil passages communicates with the main return oil passage or the oil tank via a throttling element.

Preferably, the hydraulic control feedback branch oil circuits in each of the reversing control circuits are connected to the hydraulic control feedback main oil circuit, and the hydraulic control feedback main oil circuit is connected to the main return oil circuit via the throttling element. oil circuit or tank.

Preferably, the boarding hydraulic system further includes a three-way pressure compensation valve, the oil inlet of the three-way pressure compensation valve is connected to the main oil inlet oil circuit, and the oil outlet is connected to the main oil return oil circuit, The oil inlet port of the three-way pressure compensation valve is also connected to the hydraulic control chamber port of the three-way pressure compensation valve, and the spring chamber of the three-way pressure compensation valve is connected to the hydraulic control feedback main oil circuit.

Preferably, the hydraulic control feedback main oil circuit is also connected to the main oil return oil circuit or the oil tank through a feedback overflow oil circuit provided with a feedback oil circuit relief valve.

Preferably, the first reversing valve also has a third working state corresponding to the neutral position of the valve position of the first reversing valve, and in the third working state, the oil inlet is connected to the first All to the fourth working oil ports are closed, and the oil return port is connected to the second and third working oil ports.

Preferably, the oil inlet of the first reversing valve includes a first oil inlet and a second oil inlet, and the oil return port includes a first oil return port and a second oil return port, wherein the first oil inlet The first oil return port and the second oil return port are respectively connected to the main oil return oil passage.

Preferably, the first reversing valve is an electro-hydraulic proportional reversing valve.

Preferably, in at least one of the reversing control circuits, the first working oil circuit and the second working oil circuit are provided with a two-stage fine-tuning balance valve group, and the two-stage fine-tuning balance valve group includes A first primary sequence valve, a first secondary sequence valve on a working oil circuit, a second primary sequence valve and a second secondary sequence valve arranged on the second working oil circuit, wherein the second working oil circuit is respectively Connected to the liquid control end of the first primary sequence valve and the liquid control end of the first secondary sequence valve, the hydraulic control cracking pressure of the first primary sequence valve is lower than the liquid control end of the first secondary sequence valve control cracking pressure, the oil inlet of the first secondary sequence valve is connected to the first oil port of the corresponding hydraulic actuator through the first working oil section of the first working oil circuit, and the first working oil The first working oil section of the oil circuit is also connected to the liquid control end of the first secondary sequence valve and the liquid control end of the first primary sequence valve respectively, and the oil outlet of the first secondary sequence valve is connected to the The oil inlet port of the first primary sequence valve, the oil outlet port of the first primary sequence valve is connected to the second working oil port of the first reversing valve through the second working oil circuit section of the first working oil circuit oil port; the first working oil circuit is respectively connected to the liquid control end of the second primary sequence valve and the liquid control end of the second secondary sequence valve, and the hydraulic control cracking pressure of the second primary sequence valve is less than the hydraulically controlled cracking pressure of the second secondary sequence valve, and the oil inlet of the second secondary sequence valve is connected to the corresponding hydraulic pressure through the first working oil section of the second working oil circuit. The second oil port of the actuator, the first working oil circuit section of the second working oil circuit is also respectively connected with the liquid control end of the second secondary sequence valve and the liquid control end of the second primary sequence valve, the The oil outlet of the second secondary sequence valve is connected to the oil inlet of the second primary sequence valve, and the oil outlet of the second primary sequence valve is connected to the second working oil passage section of the second working oil passage. The third working oil port of the first reversing valve; the two-stage fine-tuning balance valve group also includes a first one-way valve and a second one-way valve, and the forward oil port of the first one-way valve connected to the second working oil passage section of the first working oil passage, the reverse oil port of the first check valve is connected to the first working oil passage section of the first working oil passage, and the second one-way The forward oil port of the valve is connected to the second working oil passage section of the second working oil passage, and the reverse oil port of the second check valve is connected to the second working oil passage section of the second working oil passage.

Preferably, one of the at least two hydraulic actuators is a telescopic boom cylinder, and the two-stage fine-tuning balance valve set is set in the first working oil in the reversing control circuit corresponding to the telescopic boom cylinder. road and second working oil road.

Preferably, one of the first working oil circuit and the second working oil circuit is provided with a one-way balance valve, and the one-way balance valve includes a primary spool, a secondary spool, and a One end of the spool is connected to a return spring, and the secondary spool can be switched so that the secondary spool cooperates with the valve body of the secondary spool to form a one-way conducting oil circuit and a throttling oil circuit. The other of the first working oil circuit and the second working oil circuit is connected to the liquid control end of the primary valve core through the first intermediate oil circuit of the one-way balance valve, and the first intermediate oil circuit of the one-way balance valve is set There is a first throttle valve, and the part of the first intermediate oil circuit of the one-way balance valve between the first throttle valve and the liquid control end of the first-stage valve core passes through the second intermediate oil circuit of the one-way balance valve. The circuit is connected to the liquid control end of the secondary spool, and the second middle oil circuit of the one-way balance valve is provided with a second throttle valve, and the liquid control port of the one-way balance valve located on the primary spool The position of the control end is provided with an elastic limit torque unit, so that the hydraulic oil can act on the elastic limit torque unit through the first intermediate oil circuit of the one-way balance valve to overcome the preset elastic force of the elastic limit torque unit. The first spool drives the second-stage spool to switch in a partial stroke, and the hydraulic control end of the first-stage spool can overcome the preset elastic force of the elastic limit moment unit to push the first spool The required minimum oil pressure is less than the required minimum oil pressure of the liquid control end of the secondary spool that can push the secondary spool, when the hydraulic oil pushes the first spool through the elastic limit torque unit or When the secondary spool is pushed through the second intermediate oil passage of the one-way balance valve, the valve body and the secondary spool form a throttling oil passage, so that the actuator passes through the throttling oil. The circuit is connected to the one of the first working oil circuit and the second working oil circuit, when no hydraulic oil pushes the first spool through the elastic limit torque unit or passes through the one-way balance valve When the second intermediate oil passage acts on the secondary spool, the valve body and the secondary spool reset under the action of the return spring to form a one-way conducting oil passage, so that the corresponding hydraulic pressure The actuator is connected to the one of the first working oil passage and the second working oil passage through the one-way conducting oil passage, and the one-way conducting oil passage is configured so that the hydraulic oil can flow from the first working oil passage to the second working oil passage. The one of the first working oil passage and the second working oil passage unidirectionally flows to the corresponding hydraulic actuator.

Preferably, the elastic limit moment unit includes a tension spring and a push ball connected to each other, and the two ends of the tension spring are respectively connected to the valve body of the one-way balance valve containing the primary valve core and the On the push ball, the valve body of the primary valve core is formed with a stop platform, so that when the push ball overcomes the elastic force of the tension spring and pushes the first valve core to drive the secondary valve When the core reaches a predetermined part of the stroke, the push ball is stopped by the stopper platform, and the push ball is in sealing contact with the stopper platform to seal the first valve core in the first stage valve. core valve body.

Preferably, the one-way balance valve includes a third intermediate oil circuit of the one-way balance valve connected to the first working oil circuit and the hydraulic control end of the secondary valve core respectively, and the third intermediate oil circuit of the one-way balance valve A one-way balance valve and a third intermediate oil circuit check valve are arranged on the oil circuit, and the positive port of the third intermediate oil circuit check valve of the one-way balance valve is connected to the liquid control end of the second-stage spool, and the reverse port The port is connected to the first working oil circuit.

Preferably, the spring chamber of the return spring is connected to an actuator connection oil circuit, and the actuator connection oil circuit is connected to the one-way balance valve and the corresponding hydraulic actuator.

Preferably, one of the at least two hydraulic actuators is a jib luffing cylinder, and the one-way balance valve is arranged in the rodless chamber connected to the jib luffing cylinder. First job oil on the road.

Preferably, one of the at least two hydraulic actuators is a turntable rotary motor, and the main oil inlet circuit and the main oil return circuit are connected through a pilot valve, a second reversing valve and a one-way damping valve To the brake cylinder of the rotary motor of the turntable, the pilot valve can reduce the pressure of the hydraulic oil in the main oil inlet circuit and supply it to the brake cylinder.

Preferably, the first working oil circuit and the second working oil circuit are also respectively connected to the oil tank through an overflow working oil circuit.

Preferably, the main oil inlet circuit is respectively connected with a main oil supply pump and an emergency pump.

In addition, the present invention also provides a construction machine, wherein the construction machine includes the boarding hydraulic system according to the above technical solution.

Through the above technical solution, since the feedback oil ports of the first two-way pressure compensation valve in at least two of the reversing control circuits in the boarding hydraulic system provided by the present invention are connected to each other, at least two of the reversing control circuits The feedback oil ports of the second two-way pressure compensation valve in the circuit are connected to each other, and the feedback oil port of the first two-way pressure compensation valve and the feedback oil port of the second two-way pressure compensation valve in each of the reversing control circuits The respective hydraulic control feedback branch oil passages are connected to each other, and each of the hydraulic control feedback branch oil passages is connected to each other, so in the case of insufficient flow, the associated two-way pressure compensation valves ensure that their springs are adjusted by themselves. The pressures in the chamber and the hydraulic control chamber are dynamically balanced and equal, so that the pressure behind each first reversing valve is equal, and since the oil inlets of each first reversing valve are connected to the main oil inlet circuit, each The pre-valve pressures of the first reversing valves are equal, so that the front and rear pressure differences of each first reversing valve are equal, so the flow of hydraulic oil entering the corresponding hydraulic actuator through each first reversing valve is equal, so that the flow distribution and The load is irrelevant, which ensures the linkage when multiple hydraulic actuators move.

Other features and advantages of the present invention will be described in detail in the following detailed description.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, together with the following specific embodiments, are used to explain the present invention, but do not constitute a limitation to the present invention. In the attached picture:

Fig. 1 is a schematic diagram of the hydraulic principle of the boarding hydraulic system according to the embodiment of the present invention.

Fig. 2 is a partial enlarged view of the positions of the first reversing valve, the first two-way pressure compensating valve and the second two-way pressure compensating valve in Fig. 1 .

FIG. 3 is an enlarged schematic diagram showing a two-stage fine-tuning balance valve group according to an embodiment of the present invention.

FIG. 4 is an enlarged schematic view showing a one-way balancing valve according to an embodiment of the present invention.

Explanation of reference signs

1 The first reversing valve 2 The first working oil circuit

3 The second working oil circuit 4 The main oil inlet circuit

5 Main return oil circuit 6 Three-way pressure compensation valve

7 1st 2-way pressure compensation valve 8 2nd 2-way pressure compensation valve

9 Two-stage fine-tuning balance valve group 10 Boom telescopic cylinder

11 One-way balance valve 12 Boom luffing cylinder

13 Turntable rotary motor 14 Pilot valve

15 Second reversing valve 16 One-way damping valve

17 Overflow working oil circuit 18 Main oil supply pump

19 Emergency pump 20 Hydraulic control feedback main oil circuit

21 Flow adjustment input oil circuit 22 Flow adjustment output oil circuit

23 Feedback oil circuit relief valve 71 Feedback oil port of the first and second port pressure compensation valve

81 The second two-way pressure compensation valve feedback oil port 91 The first primary sequence valve

92 The first secondary sequence valve 93 The second primary sequence valve

94 The second secondary sequence valve 95 The first intermediate oil circuit

96 The second intermediate oil circuit 97 The first working oil circuit section of the first working oil circuit

98 The third intermediate oil circuit 99 The fourth intermediate oil circuit

100 The first working oil circuit section of the second working oil circuit

101 The first oil inlet 102 The second oil inlet

103 The first oil return port 104 The second oil return port

105 The first working oil port 106 The second working oil port

107 The third working oil port 108 The fourth working oil port

111 The first spool 112 The second spool

113 The first intermediate oil circuit of one-way balance valve 114 The second intermediate oil circuit of one-way balance valve

115 One-way balance valve third intermediate oil circuit 116 One-way balance valve third intermediate oil circuit one-way valve

Detailed ways

Specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

Referring to Fig. 1 and Fig. 2, according to one aspect of the present invention, a vehicle hydraulic system is provided, including a main oil inlet circuit 4, a main oil return circuit 5 and at least two hydraulic actuators, the at least two hydraulic actuators Each component is connected with a reversing control circuit, wherein each reversing control circuit includes: a first reversing valve 1, the first reversing valve includes a first working oil port 105, a second working oil port 106, a third working oil port port 107 and the fourth working oil port 108, and the oil inlet port of the first reversing valve 1 is connected to the main oil inlet oil circuit 4, and the oil return port is connected to the main oil return oil circuit 5, wherein the second working oil port 106 The third working oil port 107 is respectively connected to the corresponding hydraulic actuator via the first working oil passage 2 and the second working oil passage 3, and the first reversing valve 1 can be switched to at least the first and second working states, In the first working state, the oil inlet is connected to the first working oil port 105, the oil return port is connected to the third working oil port 107, and the oil inlet and the oil return port are cut off from each other and are both connected to the second working oil. Port 106 and the fourth working oil port 108 are cut off; in the second working state, the oil inlet is connected to the fourth working oil port 108, the oil return port is connected to the second working oil port 106, and the oil inlet and the oil return The ports are blocked from each other and are both blocked from the first working oil port 105 and the third working oil port 107; of course, the first reversing valve 1 can also have a position corresponding to the neutral position of the spool of the first reversing valve 1 The third working state, in the third working state, the oil inlet of the first reversing valve 1 can be connected with the first working oil port 105, the second working oil port 106, the third working oil port 107 and the fourth working oil port 108 are all closed, and the oil return port of the first reversing valve 1 can be connected with the second working oil port 106 and the third working oil port 106, specifically, the oil inlet of the first reversing valve 1 can include the first The oil port 101 and the second oil inlet 102 and the oil return port can include a first oil return port 103 and a second oil return port 104, wherein the first oil inlet 101 and the second oil inlet 102 can be connected with the main oil inlet respectively. The oil circuit 4 is connected, and the first oil return port 103 and the second oil return port 104 may be connected to the main oil return circuit 5 respectively, but the present invention is not limited thereto. Each reversing control circuit also includes a first two-way pressure compensation valve 7 and a second two-way pressure compensation valve 8, and the input oil port of the first two-way pressure compensation valve 7 is connected to the first working oil port 105 and the first two-way pressure compensation valve. The hydraulic control chamber port of the pressure compensation valve 7 is connected, and the output oil port of the first two-way pressure compensation valve 7 is connected to the first working oil circuit 2; the input oil port of the second two-way pressure compensation valve 8 is connected to the fourth working oil port. The oil port 108 and the hydraulic control chamber port of the second two-way pressure compensation valve 8, and the output oil port of the second two-way pressure compensation valve 8 are connected to the second working oil circuit 3; the first two-way pressure compensation valve 7 and The second two-way pressure compensation valve 8 also includes a two-way pressure compensation valve feedback oil port 71 and a second two-way pressure compensation valve feedback oil port 81 connected to the respective spring chambers, wherein the first two-way pressure compensation valve 7 In the state where the input oil port of the first two-way pressure compensation valve 7 is connected to the output oil port of the first two-way pressure compensation valve 7, the input oil port of the first two-way pressure compensation valve 7 can be connected to the first two-way The feedback oil port 71 of the pressure compensation valve is connected at the same time, and the second two-way pressure compensation valve 8 is in the state where the input oil port of the second two-way pressure compensation valve 8 is connected to the output oil port of the second two-way pressure compensation valve 8 The input oil port of the second two-way pressure compensation valve 8 can be connected with the feedback oil port 81 of the second two-way pressure compensation valve at the same time; wherein, the first two-way pressure compensation valve feedback oil in at least two reversing control circuits The ports 71 are connected to each other, the second two-way pressure compensation valve feedback oil port 81 in at least two reversing control circuits is connected to each other, and the first two-way pressure compensation valve feedback oil port 71 and second two-way pressure compensation valve feedback oil port 71 in each reversing control circuit The feedback oil ports 81 of the pressure compensation valve are connected to each other through respective hydraulic control feedback branch oil passages, and each hydraulic control feedback branch oil passage is connected to each other. Wherein, the first reversing valve 1 is preferably an electro-hydraulic proportional reversing valve, but the present invention is not limited thereto.

As mentioned above, since the first two-way pressure compensation valve feedback oil ports 71 in at least two reversing control circuits in the boarding hydraulic system provided by the present invention are connected to each other, the second two-way pressure compensation valves in the at least two reversing control circuits are connected to each other. The first two-way pressure compensation valve feedback oil port 71 and the second two-way pressure compensation valve feedback oil port 81 in each reversing control circuit are connected through their respective hydraulic control feedback branch oil circuits. They are connected to each other, and each hydraulic control feedback branch oil circuit is connected to each other, so in the case of insufficient flow, the associated two-way pressure compensation valves can ensure that the pressures of the spring chamber and the hydraulic control chamber reach a dynamic balance through self-regulation and equal, so that the post-valve pressures of each first reversing valve 1 are equal, and since the oil inlets of each first reversing valve 1 are connected to the main oil inlet oil circuit 4, the valves of each first reversing valve 1 The front pressure is equal, so that the front and rear pressure differences of each first reversing valve 1 are equal, so the flow of hydraulic oil entering the corresponding hydraulic actuator through each first reversing valve 1 is equal, so that the flow distribution has nothing to do with the load, ensuring Linkage when multiple hydraulic actuators move.

Specifically, each hydraulic control feedback branch oil circuit can communicate with the main oil return oil circuit 5 or the oil tank via a throttling element. The hydraulic control feedback branch oil circuits in each reversing control circuit can be connected to the hydraulic control feedback main oil circuit 20, and the hydraulic control feedback main oil circuit 20 is connected to the main return oil circuit 5 or the oil tank via a throttling element.

In addition, the boarding hydraulic system can also include a three-way pressure compensation valve 6, the oil inlet of the three-way pressure compensation valve 6 can be connected to the main oil inlet oil circuit 4 and the three-way pressure compensation valve 6 through the flow adjustment input oil circuit 21 The oil outlet of the three-way pressure compensating valve 6 can also be connected to the hydraulic control chamber port of the three-way pressure compensating valve 6 through the flow regulating output oil circuit 22 to the main oil return oil circuit 5, and the three-way pressure compensating valve 6 The spring chamber of the pressure compensating valve 6 can be connected to the hydraulic control feedback main oil circuit 20. This setting can ensure the pressure difference between the front and rear of the first reversing valve 1 to be constant through the load feedback of the three-way pressure compensating valve 6 , so that the flow rate of the hydraulic oil passing through the first reversing valve 1 is constant, so that the execution speed of the hydraulic actuator connected to the first reversing valve 1 has nothing to do with the load. It should be added that the three-way pressure compensating valve 6 is especially suitable for ensuring that the pressure difference before and after the valve of the first reversing valve 1 is constant when a single actuator in the boarding hydraulic system operates, because usually the boarding hydraulic pressure When the compound action occurs in the system (that is, multiple hydraulic actuators act at the same time), the flow provided by the hydraulic system on the vehicle may not meet the rated flow required for the compound action. At this time, the three-way pressure compensation valve 6 will be closed due to insufficient flow. When compound action occurs in the hydraulic system of the boarding car, the above-mentioned two-way pressure compensating valves are generally used to ensure that the front and rear pressure differences of each first reversing valve 1 are equal. Since the above has specifically explained how each two-way pressure compensating valve The front and rear pressure differences of each first reversing valve 1 are equal, which will not be repeated here.

According to a preferred embodiment of the present invention, the hydraulic control feedback main oil circuit 20 can also be connected to the main return oil circuit 5 or the oil tank through a feedback overflow oil circuit provided with a feedback oil circuit overflow valve 23 .

It can be seen from Fig. 1 and Fig. 3 that in at least one reversing control circuit, the first working oil circuit 2 and the second working oil circuit 3 can also be provided with a two-stage fine-tuning balance valve group 9, the two-stage fine-tuning balance The valve group 9 may include a first primary sequence valve 91 and a first secondary sequence valve 92 provided on the first working oil circuit 2, a second primary sequence valve 93 and a second secondary sequence valve provided on the second working oil circuit 3. stage sequence valve 94, wherein the second working oil circuit 3 can be connected to the liquid control end of the first primary sequence valve 91 through the first intermediate oil circuit 95, and the first intermediate oil circuit 95 can be connected to the At the liquid control end of the first secondary sequence valve 92, the hydraulic control cracking pressure of the first primary sequence valve 91 is lower than the hydraulic control cracking pressure of the first secondary sequence valve 92, and the oil inlet of the first secondary sequence valve 92 can pass through The first working oil passage section 97 of the first working oil passage is connected to the first oil port of the corresponding hydraulic actuator, and the first working oil passage section 97 of the first working oil passage can also be connected with the hydraulic fluid of the first secondary sequence valve 92 respectively. The control end is connected to the liquid control end of the first primary sequence valve 91, and the oil outlet of the first secondary sequence valve 92 can be connected to the oil inlet port of the first primary sequence valve 91, and the oil outlet of the first primary sequence valve 91 The port can be connected to the second working oil port 106 of the first reversing valve via the second working oil passage section of the first working oil passage 2; the first working oil passage 2 can be connected to the second primary sequence through the third intermediate oil passage 98 The liquid control end of the valve 93, and the third intermediate oil circuit 98 can be connected to the liquid control end of the second secondary sequence valve 94 through the fourth intermediate oil circuit 99, and the hydraulic control cracking pressure of the second primary sequence valve 93 is lower than the second The hydraulic control opening pressure of the secondary sequence valve 94, and the oil inlet port of the second secondary sequence valve 94 can be connected to the second oil port of the corresponding hydraulic actuator through the first working oil circuit section 100 of the second working oil circuit , the first working oil section 100 of the second working oil circuit can also be connected with the liquid control end of the second secondary sequence valve 94 and the liquid control end of the second primary sequence valve 93 respectively, and the outlet of the second secondary sequence valve 94 The oil port can be connected to the oil inlet port of the second primary sequence valve 93, and the oil outlet port of the second primary sequence valve 93 can be connected to the third port of the first reversing valve via the second working oil section of the second working oil circuit. Working oil port 107; the two-stage fine-tuning balance valve group 9 can also include a first one-way valve and a second one-way valve, and the forward oil port of the first one-way valve can be connected to the second working oil port of the first working oil circuit 2. The oil passage section, the reverse oil port of the first check valve can be connected to the first working oil passage section 97 of the first working oil passage, and the forward oil port of the second check valve can be connected to the first working oil passage section 97 of the second working oil passage 3 The second working oil circuit section, the reverse oil port of the second check valve can be connected to the second working oil circuit section 100 of the second working oil circuit.

One of the above at least two hydraulic actuators may be a boom telescopic oil cylinder 10, and the two-stage fine-tuning balance valve group 9 is arranged in the first working oil circuit 2 in the reversing control circuit corresponding to the boom telescopic oil cylinder 10 and the second working oil passage 3, and the present invention is not limited thereto. When the two-stage fine-tuning balance valve group 9 is set in the reversing control circuit of the boom telescopic cylinder 10, how the two-stage fine-tuning balance valve group 9 works will be explained by taking the retracting working condition of the boom telescopic cylinder 10 as an example. 1 and 3, when the telescopic oil cylinder 10 of the boom is retracted, the hydraulic oil enters the two-stage fine-tuning balance valve group 9 from the second working oil circuit 3 and is divided into two circuits of hydraulic oil, and one hydraulic oil channel passes through the first The second one-way valve enters the rod cavity of the telescopic cylinder 10 of the boom, and the other hydraulic oil enters the first intermediate oil circuit 95, and then the hydraulic oil entering the first intermediate oil circuit 95 is divided into two hydraulic oils respectively acting on a primary The hydraulic control end of the sequence valve 91 and the liquid control end of the first secondary sequence valve 92, because the hydraulic control cracking pressure of the first primary sequence valve 91 is less than the hydraulic control cracking pressure of the first secondary sequence valve 92, so that a primary The spool of the sequence valve 91 and the spool of the first secondary sequence valve 92 are opened sequentially. During this process, they play the role of a counterweight and increase the back pressure of the load, so that the two-stage fine-tuning balance valve group 9 Open more smoothly.

As can be seen from Figures 1 and 4, one of the first working oil circuit 2 and the second working oil circuit 3 may be provided with a one-way balance valve 11, and the one-way balance valve 11 may include a primary spool 111, the secondary spool 112 and the return spring connected to one end of the secondary spool 112, the secondary spool 112 can be switched so that the secondary spool 112 cooperates with the valve body of the secondary spool 112 to form One-way conducting oil passage and throttling oil passage, the other of the first working oil passage 2 and the second working oil passage 3 can be connected to the hydraulic fluid of the primary spool 111 through the first intermediate oil passage 113 of the one-way balance valve. At the control end, the first intermediate oil circuit 113 of the one-way balance valve may be provided with a first throttle valve, and the first intermediate oil circuit 113 of the one-way balance valve is located at the first throttle valve and the hydraulic control valve of the primary valve core 111 The part between the two ends is connected to the liquid control end of the secondary valve core 112 through the second intermediate oil passage 114 of the one-way balance valve, and the second intermediate oil passage 114 of the one-way balance valve can be provided with a second throttle valve. The position of the balance valve 11 located at the liquid control end of the first-stage spool 111 can be provided with an elastic limit torque unit, so that the hydraulic oil can act on the elastic limit torque unit through the first intermediate oil circuit 113 of the one-way balance valve. Overcome the preset elastic force of the elastic limit torque unit to push the first spool 111 to drive the secondary spool 112 to switch in a partial stroke, and the liquid control end of the primary spool 111 can overcome the preset elasticity of the elastic limit torque unit The required minimum oil pressure to push the first spool 111 is less than the required minimum oil pressure of the liquid control end of the secondary spool 112 that can push the secondary spool. When the first spool 111 or the second intermediate oil passage 114 of the one-way balance valve pushes the second-stage spool 112, the valve body and the second-stage spool 112 form a throttling oil passage, so that the actuator passes through the throttling oil passage and the first One of the working oil circuit 2 and the second working oil circuit 3 is connected, when there is no hydraulic oil to push the first spool 111 through the elastic limit torque unit or act on the secondary valve through the second intermediate oil circuit 114 of the one-way balance valve core 112, the valve body and the secondary spool 112 are reset under the action of the return spring to form a one-way conduction oil passage, so that the corresponding hydraulic actuator communicates with the first working oil passage 2 and the second through the one-way conduction oil passage. One of the working oil passages 3 is connected, and the one-way conducting oil passage is set so that hydraulic oil can flow unidirectionally from one of the first working oil passage 2 and the second working oil passage 3 to the corresponding hydraulic actuator .

Specifically, the elastic limit moment unit may include a tension spring and a push ball connected to each other, and the two ends of the tension spring may be respectively connected to the valve body and the push ball of the one-way balance valve 11 accommodating the primary valve core 111 The valve body of the first-stage spool 111 is formed with a stop platform, so that when the push ball overcomes the elastic force of the tension spring and pushes the first spool 111 to drive the second-stage spool 112 to a predetermined partial stroke, the push ball is The stop platform stops, and the push ball is in sealing contact with the stop platform to seal the first valve core 111 in the valve body of the primary valve core 111 . In addition, the one-way balance valve 11 may also include a one-way balance valve third intermediate oil circuit 115 connected to the first working oil circuit 2 and the hydraulic control end of the secondary valve core 112 respectively, and the one-way balance valve third intermediate oil circuit 115 A one-way balance valve third intermediate oil circuit check valve 116 may be provided on the road 115. The port is connected to the first working oil circuit 2, the spring chamber of the return spring can be connected to the actuator connection oil circuit, and the actuator connection oil circuit can be connected to the one-way balance valve 11 and the corresponding hydraulic actuator, so that the return spring can be The pressure oil in the spring chamber is removed in time by connecting the one-way balance valve 11.

One of the above at least two hydraulic actuators may be the jib luffing cylinder 12 , and the one-way balance valve 11 may be arranged on the first working oil circuit connected to the rodless chamber of the jib luffing cylinder 12 . When the one-way balance valve 11 is set in the reversing control circuit of the jib luffing cylinder 12, how the one-way balance valve 11 works will be explained by taking the luffing and lowering working condition of the jib luffing cylinder 12 as an example. In other words, still referring to Fig. 1 and Fig. 4, it is shown in the figure that the one-way balancing valve 11 is arranged on the first working oil passage 2, and the second working oil passage 3 passes through the first intermediate oil passage 113 of the one-way balancing valve. Connected to the hydraulic control end of the primary spool 111, when the boom luffing cylinder 12 descends, part of the hydraulic oil in the second working oil circuit 3 enters the rod chamber of the boom luffing cylinder 12, and the other part of the hydraulic oil After entering the first intermediate oil circuit 113 of the one-way balance valve, it reaches the liquid control end of the primary valve core 111, and then pushes the first valve core 111 through the elastic limit torque unit to drive the secondary valve core 112 to move to a part of the stroke (this part of the stroke It is a stroke in the complete stroke that the secondary spool 112 can move. For example, when the secondary spool 112 can move from the left position to the right position, the position corresponding to the partial stroke of the secondary spool 112 is the left position. position between position and right position), at this moment, the primary spool 111 is limited by the limit action of the elastic limit torque unit (in the preferred embodiment provided by the present invention, due to the push ball is stopped stop, so the first-stage spool 111 cannot be further pushed by the push ball and is limited), and then the hydraulic oil passes through the second intermediate oil circuit 114 of the one-way balance valve to reach the liquid control end of the second-stage spool 112, thereby Push the secondary spool 112 to move further, so that the spool of the one-way balance valve 11 is fully opened (at this time, the one-way balance valve 11 is still formed as a throttling oil circuit), so that the boom luffing cylinder 12 is in the throttling oil circuit. In the above process, because the hydraulic oil in the second intermediate oil circuit 114 of the balance valve reaches the minimum pressure that can push the secondary valve core 112, it takes a certain pressure building time, so that the one-way balance valve 11 can be opened more slowly, avoiding the phenomenon of pressure shock caused by the sudden full opening of the traditional balance valve when the pressure reaches the pilot pressure. In addition, when no hydraulic oil acts on the jib luffing cylinder 12, the one-way balance valve 11 returns to the position forming the one-way conducting oil circuit under the reset action of the return spring, so as to prevent the jib luffing cylinder 12 from being rodless. The hydraulic oil in the chamber leaks.

It can be seen from Fig. 1 that one of the at least two hydraulic actuators can be a turntable rotary motor 13, and the main oil inlet oil circuit 4 and the main oil return oil circuit 5 pass through the pilot valve 14, the second reversing valve 15 and the one-way damping valve 16 are connected to the brake cylinder of the rotary motor 13 of the turntable, and the pilot valve 14 can reduce the pressure of the hydraulic oil in the main oil inlet circuit 4 and supply it to the brake cylinder. When the second reversing valve 15 When the turntable rotary motor 13 is controlled to start, the hydraulic oil can enter the brake cylinder through the one-way valve in the one-way damping valve 16. When the second reversing valve 15 controls the turntable rotary motor 13 to brake and stop, the hydraulic oil in the brake cylinder The oil can be slowly unloaded through the throttle plug in the one-way damping valve 16, so that the turntable rotary motor 13 can be turned on and off quickly, so as to achieve the purpose of smoothness and no impact.

In addition, the first working oil passage 2 and the second working oil passage 3 can also be connected to the oil tank through the overflow working oil passage 17 respectively. The main oil inlet oil circuit 4 can be respectively connected with a main oil supply pump 18 and an emergency pump 19, so that the boarding hydraulic system has a certain emergency compensation function.

According to another aspect of the present invention, a construction machine is provided, wherein the construction machine includes the boarding hydraulic system described in the above technical solution, and because of the many advantages of the boarding hydraulic system listed above, this Undoubtedly, the overall performance and quality of the engineering machinery including the boarding hydraulic system are improved.

The preferred embodiment of the present invention has been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the specific details of the above embodiment, within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, These simple modifications all belong to the protection scope of the present invention.

In addition, it should be noted that the various specific technical features described in the above specific implementation manners may be combined in any suitable manner if there is no contradiction. In order to avoid unnecessary repetition, various possible combinations are not further described in the present invention.

In addition, various combinations of different embodiments of the present invention can also be combined arbitrarily, as long as they do not violate the idea of the present invention, they should also be regarded as the disclosed content of the present invention.

Claims (19)

1. A boarding hydraulic system, comprising a main oil inlet circuit (4), a main oil return circuit (5) and at least two hydraulic actuators, each of which is connected with a reversing control loop, wherein each of the commutation control loops includes: The first reversing valve (1), which includes first to fourth working oil ports (105, 106, 107, 108), and the oil inlet of the first reversing valve (1) is connected to the main oil inlet The oil passage (4) and the oil return port are connected to the main oil return oil passage (5), wherein the second working oil port (106) and the third working oil port (107) respectively pass through the first working oil The passage (2) and the second working oil passage (3) are connected to the corresponding hydraulic actuators, and the first reversing valve (1) can at least be switched to the first and second working states, wherein in the first working state state, the oil inlet is connected to the first working oil port (105), the oil return port is connected to the third working oil port (107), and the oil inlet and the oil return port are cut off from each other and both It is closed with the second working oil port (106) and the fourth working oil port (108); in the second working state, the oil inlet is connected to the fourth working oil port (108), and the oil return port communicate with the second working oil port (106), and the oil inlet port and the oil return port are cut off from each other and both are cut off from the first working oil port (105) and the third working oil port (107); First and second two-way pressure compensation valves (7, 8), the input oil port of the first two-way pressure compensation valve (7) is connected to the first working oil port (105) and the first two-way The port of the hydraulic control chamber of the pressure compensation valve (7) and the output oil port are connected to the first working oil circuit (2); the input oil port of the second two-way pressure compensation valve (8) is connected to the first Four working oil ports (108) and the hydraulic control cavity port of the second two-way pressure compensating valve (8), and the output oil port are connected to the second working oil circuit (3); the first and second two The one-way pressure compensating valves (7, 8) also include feedback oil ports (71, 81) connected to the respective spring chambers, wherein the first and second two-way pressure compensating valves (7, 8) are connected to the respective spring chambers. In the state where the input oil ports are connected to the respective output oil ports, the respective input oil ports and the respective feedback oil ports (71, 81) can be simultaneously conducted; Wherein, the first two-way pressure compensation valve feedback ports (71) in at least two of the reversing control circuits are connected to each other, and the second two-way pressure compensation valves in at least two of the reversing control circuits are connected to each other. The valve feedback oil ports (81) are connected to each other, and the first two-way pressure compensation valve feedback oil port (71) and the second two-way pressure compensation valve feedback oil port (81) in each of the reversing control circuits pass through their respective The hydraulic control feedback branch oil circuits are connected to each other, and each of the hydraulic control feedback branch oil circuits is connected to each other. 2. The boarding hydraulic system according to claim 1, characterized in that each of the hydraulic control feedback branch oil passages communicates with the main return oil passage (5) or the fuel tank via a throttling element. 3. The boarding hydraulic system according to claim 1, characterized in that, the hydraulic control feedback branch oil circuits in each of the reversing control circuits are connected to the hydraulic control feedback main oil circuit (20), and the hydraulic control feedback branch oil circuits (20) are connected to each other. The control feedback main oil circuit (20) is connected to the main oil return oil circuit (5) or the oil tank via the throttling element. 4. The on-board hydraulic system according to claim 3, characterized in that the on-board hydraulic system also includes a three-way pressure compensation valve (6), and the oil inlet of the three-way pressure compensation valve (6) is connected to The main oil inlet circuit (4) and the oil outlet port are connected to the main oil return circuit (5), and the oil inlet port of the three-way pressure compensation valve (6) is also connected to the three-way pressure compensation valve ( 6) is connected to the port of the hydraulic control chamber, and the spring chamber of the three-way pressure compensation valve (6) is connected to the hydraulic control feedback main oil circuit (20). 5. The boarding hydraulic system according to claim 4, characterized in that, the hydraulic control feedback main oil circuit (20) is also connected to the The main return oil circuit (5) or oil tank. 6. The boarding hydraulic system according to claim 1, characterized in that, the first reversing valve (1) also has a neutral position corresponding to the valve position of the first reversing valve (1). In the third working state, in the third working state, the oil inlet port and the first to fourth working oil ports (105, 106, 107, 108) are all closed, and the oil return port is connected to the second It is connected with the third working oil port (106, 107). 7. The boarding hydraulic system according to claim 6, characterized in that, the oil inlet of the first reversing valve (1) comprises a first oil inlet (101) and a second oil inlet (102) , The oil return port includes a first oil return port (103) and a second oil return port (104), wherein the first oil inlet (101) and the second oil inlet (102) are respectively connected to the main oil inlet The oil circuit (4) is connected, and the first oil return port (103) and the second oil return port (104) are respectively connected with the main oil return circuit (5). 8. The boarding hydraulic system according to any one of claims 1 to 7, characterized in that, the first reversing valve (1) is an electro-hydraulic proportional reversing valve. 9. The boarding hydraulic system according to any one of claims 1 to 7, characterized in that, in at least one of the reversing control circuits, the first working oil passage (2) and the second working oil A two-stage fine-tuning balance valve group (9) is provided on the road (3), and the two-stage fine-tuning balance valve group (9) includes a first primary sequence valve (91) arranged on the first working oil circuit (2) ), the first secondary sequence valve (92) and the second primary sequence valve (93) and the second secondary sequence valve (94) arranged on the second working oil circuit (3), wherein The second working oil circuit (3) is respectively connected to the liquid control end of the first primary sequence valve (91) and the liquid control end of the first secondary sequence valve (92). The hydraulically controlled cracking pressure of the valve (91) is lower than the hydraulically controlled cracking pressure of the first secondary sequence valve (92), and the oil inlet of the first secondary sequence valve (92) passes through the first working oil circuit The first working oil circuit section (97) of the first working oil circuit is connected to the first oil port of the corresponding hydraulic actuator, and the first working oil circuit section (97) of the first working oil circuit is also connected with the first secondary sequence The liquid control end of the valve (92) is connected to the liquid control end of the first primary sequence valve (91), and the oil outlet of the first secondary sequence valve (92) is connected to the first primary sequence valve (91) The oil inlet port of the first primary sequence valve (91) is connected to the second working oil port of the first reversing valve via the second working oil circuit section of the first working oil circuit (2). Oil port (106); The first working oil circuit (2) is respectively connected to the liquid control end of the second primary sequence valve (93) and the liquid control end of the second secondary sequence valve (94), and the second primary sequence valve (94) The hydraulically controlled cracking pressure of the valve (93) is lower than the hydraulically controlled cracking pressure of the second secondary sequence valve (94), and the oil inlet of the second secondary sequence valve (94) passes through the second working The first working oil circuit section (100) of the oil circuit is connected to the second oil port of the corresponding hydraulic actuator, and the first working oil circuit section (100) of the second working oil circuit is also connected to the second The liquid control end of the primary sequence valve (94) is connected to the liquid control end of the second primary sequence valve (93), and the oil outlet of the second secondary sequence valve (94) is connected to the second primary sequence valve ( 93), the oil outlet of the second primary sequence valve (93) is connected to the third working oil of the first reversing valve via the second working oil section of the second working oil circuit Mouth(107); The two-stage fine-tuning balance valve group (9) also includes a first one-way valve and a second one-way valve, and the forward oil port of the first one-way valve is connected to the first working oil circuit (2). The second working oil circuit section, the reverse oil port of the first one-way valve is connected to the first working oil circuit section (97) of the first working oil circuit, and the forward oil port of the second one-way valve is connected to To the second working oil passage section of the second working oil passage (3), the reverse oil port of the second check valve is connected to the second working oil passage section (100) of the second working oil passage. 10. The boarding hydraulic system according to claim 9, characterized in that one of the at least two hydraulic actuators is a boom telescopic oil cylinder (10), and the two-stage fine-tuning balance valve group ( 9) It is arranged on the first working oil circuit (2) and the second working oil circuit (3) in the reversing control circuit corresponding to the telescopic oil cylinder (10) of the boom. 11. The boarding hydraulic system according to any one of claims 1 to 7, characterized in that, one of the first working oil circuit (2) and the second working oil circuit (3) is provided with A one-way balance valve (11), the one-way balance valve (11) includes a primary spool (111), a secondary spool (112) and a return spring connected to one end of the secondary spool (112), The secondary spool (112) can be switched so that the secondary spool (112) cooperates with the valve body of the secondary spool (112) to form a one-way conducting oil passage and a throttling oil passage. The other of the first working oil circuit (2) and the second working oil circuit (3) is connected to the liquid control end of the primary spool (111) through the first intermediate oil circuit (113) of the one-way balance valve , the first intermediate oil circuit (113) of the one-way balance valve is provided with a first throttle valve, and the first intermediate oil circuit (113) of the one-way balance valve is located between the first throttle valve and the one The part between the liquid control ends of the stage spool (111) is connected to the liquid control end of the secondary spool (112) through the second intermediate oil passage (114) of the one-way balance valve, and the one-way balance valve The second intermediate oil circuit (114) is provided with a second throttle valve, and the position of the one-way balance valve (11) located at the liquid control end of the first-stage valve core (111) is provided with an elastic limit torque unit, Pushing the first spool (111) with the preset elastic force that can make the hydraulic oil pass through the first intermediate oil passage (113) of the one-way balance valve and act on the elastic limit moment unit to overcome the elastic limit moment unit ) drives the second-stage spool (112) to switch over a partial stroke, and the liquid control end of the first-stage spool (111) can overcome the preset elastic force of the elastic limit moment unit to push the first valve The required minimum oil pressure of the spool (111) is lower than the required minimum oil pressure of the liquid control end of the secondary spool (112) that can push the secondary spool, when the hydraulic oil is pushed through the elastic limit torque unit When the first spool (111) or the second intermediate oil passage (114) of the one-way balance valve pushes the secondary spool (112), the valve body and the secondary spool (112) ) to form a throttling oil passage, so that the actuator is connected to the one of the first working oil passage (2) and the second working oil passage (3) through the throttling oil passage, when there is no When the hydraulic oil pushes the first spool (111) through the elastic limit torque unit or acts on the secondary spool (112) through the second intermediate oil passage (114) of the one-way balance valve, the The valve body and the secondary spool (112) are reset under the action of the return spring to form a one-way conducting oil passage, so that the corresponding hydraulic actuator passes through the one-way conducting oil passage and the The first working oil passage (2) is connected to the one of the second working oil passage (3), and the one-way conducting oil passage is set so that the hydraulic oil can flow from the first working oil passage (2) The one of the second working oil passage (3) and the second working oil passage (3) flows to the corresponding hydraulic actuator in one direction. 12. The boarding hydraulic system according to claim 11, wherein the elastic limit moment unit comprises a tension spring and a push ball connected to each other, and the two ends of the tension spring are respectively connected to the one-way On the valve body of the balance valve (11) containing the first-stage valve core (111) and the push ball, the valve body of the first-stage valve core (111) is formed with a stop platform, so that when the push ball When the ball overcomes the elastic force of the tension spring and pushes the first spool (111) to drive the secondary spool (112) to a predetermined partial stroke, the pushing ball is stopped by the stop table , and the push ball is in sealing contact with the stop platform to seal the first valve core (111) in the valve body of the primary valve core (111). 13. The boarding hydraulic system according to claim 11, characterized in that, the one-way balance valve (11) includes a The third intermediate oil circuit (115) of the one-way balance valve connected to the liquid control end of the one-way balance valve is provided with a one-way balance valve third intermediate oil circuit check valve (116) on the third intermediate oil circuit (115) of the one-way balance valve , the positive port of the third intermediate oil circuit check valve (116) of the one-way balance valve is connected to the liquid control end of the secondary valve core (112), and the reverse port is connected to the first working oil circuit (2). 14. The boarding hydraulic system according to claim 11, characterized in that, the spring chamber of the return spring is connected to the actuator connection oil circuit, and the actuator connection oil circuit is connected to the one-way balance valve (11) and The corresponding hydraulic actuators. 15. The boarding hydraulic system according to claim 11, characterized in that one of the at least two hydraulic actuators is a jib luffing cylinder (12), and the one-way balance valve (11) It is arranged on the first working oil circuit connected with the rodless chamber of the boom luffing cylinder (12). 16. The boarding hydraulic system according to any one of claims 1 to 7, characterized in that one of the at least two hydraulic actuators is a turntable rotary motor (13), and the main drive The oil circuit (4) and the main oil return circuit (5) are connected to the brake of the turntable rotary motor (13) through the pilot valve (14), the second reversing valve (15) and the one-way damping valve (16). The pilot valve (14) can reduce the pressure of the hydraulic oil in the main oil inlet circuit (4) and supply it to the brake oil cylinder. 17. The boarding hydraulic system according to any one of claims 1 to 7, characterized in that, the first working oil circuit (2) and the second working oil circuit (3) also pass through the overflow working oil Road (17) is connected to the fuel tank. 18. The boarding hydraulic system according to any one of claims 1 to 7, characterized in that, the main oil inlet circuit (4) is respectively connected with a main oil supply pump (18) and an emergency pump (19). 19. A construction machine, characterized in that the construction machine comprises the boarding hydraulic system according to any one of claims 1-18.