Hydraulic system and raise boring machine

Abstract

The utility model discloses a hydraulic system and a raise boring machine. The hydraulic system comprises an oil tank; the cooler is provided with an oil inlet pipe and an oil outlet pipe which is communicated with the oil tank; the open pump is provided with an oil suction pipe and an oil outlet pipe, and the oil suction pipe communicates with the oil tank; the unloading valve group is provided with a first interface and a second interface, the first interface is communicated with the oil outlet pipe, and the second interface is communicated with the oil inlet pipe; the unloading valve group has a power-on state and a power-off state, and the unloading valve group in the power-off state is communicated with the oil outlet pipe and the oil inlet pipe so as to circularly cool oil in the oil tank; the unloading valve group in a power-on state cuts off communication between the oil outlet pipe and the oil inlet pipe; the control assembly is used for controlling the unloading valve set to be switched between the power-on state and the power-off state. According to the hydraulic system provided by the embodiment of the utility model, the temperature of hydraulic oil in the oil tank can be effectively reduced, so that the temperature of the hydraulic oil in the closed hydraulic system is reduced, and the service life of hydraulic components is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of hydraulic systems, in particular to a hydraulic system and a raise drilling rig. Background Art

[0002] As an important construction machinery in mining machinery, the raise drill has been widely used in various shaft and tunnel construction in mine construction. Its mechanical application is characterized by long working time, heavy workload and harsh working environment. The hydraulic system of the raise drill includes a closed hydraulic system and an open hydraulic system, which are not connected to each other; the closed hydraulic system is usually composed of a closed pump, a flushing valve and a rotary motor. The characteristic is that the closed pump directly drives the hydraulic motor to work, which is suitable for large flow, high load and long-term working conditions, and is a common working condition for the raise drill. However, the closed system has natural defects in heat dissipation capacity, which makes the equipment unable to work normally under high load for a long time, seriously affecting the drilling progress of the drill. Long-term high temperature also has a great impact on the service life of the hydraulic components of the equipment.

[0003] At present, closed hydraulic systems usually use flushing valves to allow part of the hot oil in the closed hydraulic system to enter the oil tank after cooling, and then the oil replenishing pump re-draws the low-temperature hydraulic oil in the oil tank to replenish the closed hydraulic system to reduce the overall oil temperature in the closed hydraulic system. However, since the flushing flow of the flushing valve is relatively small, the cooled hydraulic oil is also relatively small. The hydraulic oil replenished by the oil replenishing pump is difficult to reduce the temperature of the closed hydraulic system. The increase in the temperature of the hydraulic oil in the closed hydraulic system will affect the service life of various hydraulic components. Utility Model Content

[0004] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model proposes a hydraulic system that can effectively reduce the temperature of the hydraulic oil in the oil tank, thereby reducing the operating temperature of the hydraulic system, thereby increasing the service life of hydraulic components.

[0005] The utility model also provides a skydrilling machine adopting the hydraulic system.

[0006] According to the first embodiment of the present invention, the hydraulic system comprises:

[0007] tank;

[0008] A cooler having an oil inlet pipe and an oil drain pipe, wherein the oil drain pipe is connected to the oil tank;

[0009] An open pump having an oil suction pipe and an oil discharge pipe, wherein the oil suction pipe is connected to the oil tank;

[0010] The unloading valve group has a first interface and a second interface, wherein the first interface is connected to the oil outlet pipe, and the second interface is connected to the oil inlet pipe; the unloading valve group has an energized state and a de-energized state, wherein the unloading valve group in the de-energized state is connected to the oil outlet pipe and the oil inlet pipe to circulate and cool the oil in the oil tank; and the unloading valve group in the energized state cuts off the connection between the oil outlet pipe and the oil inlet pipe;

[0011] A control component is used to control the unloading valve group to switch between the energized state and the de-energized state.

[0012] The hydraulic system according to the embodiment of the utility model has at least the following beneficial effects:

[0013] By providing an unloading valve group, and the unloading valve group can connect the oil outlet pipe of the open pump and the oil inlet pipe of the cooler, the open pump can be used to actively circulate and cool the hydraulic oil in the oil tank, effectively reducing the temperature of the hydraulic oil in the oil tank, thereby increasing the service life of the hydraulic components.

[0014] According to some embodiments of the utility model, the unloading valve group includes a differential valve and a first oil pipe, both ends of the first oil pipe are respectively connected to the first interface and the second interface, and the differential valve is arranged on the first oil pipe to control the opening and closing of the first oil pipe.

[0015] According to some embodiments of the utility model, the differential valve includes a housing and a piston slidably installed in the housing, and the two ends of the piston respectively form a first chamber and a second chamber with the inner wall of the housing. The pressure difference between the first chamber and the second chamber is used to push the piston to slide, thereby realizing the opening and closing of the first oil pipe.

[0016] According to some embodiments of the utility model, the unloading valve group further includes a control valve and a second oil pipe, two ends of the second oil pipe are respectively connected to the first interface and the control valve, and an intermediate pipe is provided between the control valve and the second chamber;

[0017] When the unloading valve group is in an energized state, the first oil pipe supplies oil to the first chamber, and the second oil pipe supplies oil to the second chamber through the intermediate pipe;

[0018] When the unloading valve group is in a power-off state, the first oil pipe supplies oil to the first chamber, and the second oil pipe is not connected to the intermediate pipe.

[0019] According to some embodiments of the present invention, the control component is electrically connected to the control valve.

[0020] According to some embodiments of the utility model, an overflow pipe is further included, and both ends of the overflow pipe are respectively connected to the control valve and the oil tank; when the unloading valve group is in a power-off state, the overflow pipe is connected to the intermediate pipe.

[0021] According to some embodiments of the utility model, a closed pump and a flushing valve are further included, wherein the closed pump has a first oil discharge pipeline and a second oil discharge pipeline, and the flushing valve is provided with a first oil port, a second oil port and a third oil port, wherein the first oil port is communicated with the first oil discharge pipeline, the second oil port is communicated with the second oil discharge pipeline, and the third oil port is communicated with the oil inlet pipe;

[0022] If the medium pressure in the first oil discharge pipeline is greater than the medium pressure in the second oil discharge pipeline, the second oil port is connected to the third oil port;

[0023] If the medium pressure in the first oil discharge pipeline is lower than the medium pressure in the second oil discharge pipeline, the first oil port is communicated with the third oil port.

[0024] According to some embodiments of the present invention, an oil replenishment pump is further included, and the oil replenishment pump is used to replenish hydraulic oil into the hydraulic system.

[0025] According to some embodiments of the present invention, the cooler is a water-cooled cooler.

[0026] The drilling rig according to the embodiment of the second aspect of the utility model adopts the above-mentioned hydraulic system.

[0027] The raise boring machine according to the embodiment of the utility model has at least the following beneficial effects:

[0028] It can actively circulate and cool the hydraulic oil in the oil tank, thereby keeping the hydraulic oil at a lower temperature, extending the service life of the hydraulic equipment and making the drilling rig suitable for large flow, high load and long-term working conditions.

[0029] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention is further described below with reference to the accompanying drawings and embodiments, wherein:

[0031] Figure 1 This is a structural schematic diagram of a hydraulic system according to an embodiment of the utility model;

[0032] Figure 2 for Figure 1 The enlarged view of point A in the middle;

[0033] Figure 3It is a structural schematic diagram of a hydraulic system in the prior art.

[0034] Figure Number:

[0035] Fuel tank 100;

[0036] Cooler 200, oil inlet pipe 210, oil drain pipe 220;

[0037] Open pump 300, oil suction pipe 310, oil outlet pipe 320;

[0038] Unloading valve group 400, first interface 401, second interface 402, differential valve 410, housing 411, piston 412, first chamber 413, second chamber 414, control valve 420, first oil pipe 430, second oil pipe 440, overflow pipe 450, intermediate pipe 460;

[0039] Flushing valve 500 , first oil port 510 , second oil port 520 , third oil port 530 . DETAILED DESCRIPTION

[0040] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0041] In the description of the present invention, it should be understood that the descriptions involving orientation, such as the orientation or positional relationship indicated as up, down, etc., are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0042] In the description of the present utility model, "a plurality" means more than two. If there is a description of "first" or "second", it is only for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0043] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0044] The hydraulic system of a well drilling rig generally includes two parts: a closed hydraulic system and an open hydraulic system. The closed hydraulic system is mainly composed of a closed pump, a flushing valve 500, and a rotary motor. The closed hydraulic system is characterized in that the closed pump directly drives the hydraulic motor to provide the torque and speed required for the drilling rig to guide and expand the hole. It is suitable for large flow, high load, and long-term working conditions, which are common working conditions of the well drilling rig; the open hydraulic system is mainly composed of an open pump 300, a multi-way valve, a travel motor or a cylinder. It is often used in the hydraulic system of the well drilling rig to play auxiliary roles such as advancing the reduction box, reverse lifting the reduction box, unloading the drill rod, and clamping the drill rod; the general open hydraulic system has two sets of open pumps 300. In the auxiliary working condition, the full flow of the two sets of open pumps 300 is required only when the reduction box is rapidly advanced or reversed. Therefore, in the non-rapid reverse lifting or advancing working condition, only one set of open pumps 300 is required to provide the flow.

[0045] When a skydrill is working under high flow, high load, and long-term conditions, the closed hydraulic system will have the problem of insufficient heat dissipation, resulting in an increase in the temperature of the hydraulic oil running in the closed hydraulic system, which may seriously affect the service life of the hydraulic equipment. Currently, closed hydraulic systems usually use a flushing valve to allow part of the hot oil in the closed hydraulic system to enter the oil tank after cooling, and then the oil replenishing pump re-draws the low-temperature hydraulic oil in the oil tank to replenish the closed hydraulic system to reduce the overall oil temperature in the closed hydraulic system. However, since the flushing flow of the flushing valve is relatively small, the cooled hydraulic oil is also relatively small, and the hydraulic oil replenished by the oil replenishing pump is difficult to reduce the temperature of the closed hydraulic system. In order to solve the above-mentioned technical problems, this embodiment proposes a hydraulic system suitable for a skydrill, which is improved on the basis of the existing hydraulic system and effectively solves the problem of increased temperature of the hydraulic oil in the closed hydraulic system when the skydrill is working under high flow, high load, and long-term conditions. The following is combined with the attached Figures 1 to 3 The hydraulic system of the first aspect of this embodiment is described in detail.

[0046] Figure 3 The closed hydraulic system includes a closed pump, a supplementary oil pump, a flushing valve 500 and a cooler 200. The closed pump and the supplementary oil pump are Figure 3 Not shown, the oil replenishment pump draws hydraulic oil from the oil tank 100 and then replenishes the oil supply to the closed hydraulic system; the closed pump has a first oil outlet pipeline and a second oil outlet pipeline, and the flushing valve 500 is provided with a first oil port 510, a second oil port 520 and a third oil port 530, the first oil port 510 is connected to the first oil outlet pipeline, the second oil port 520 is connected to the second oil outlet pipeline, and the third oil port 530 is connected to the cooler 200. The cooler 200 has an oil inlet pipe 210 and an oil outlet pipe 220, the oil outlet pipe 220 is connected to the oil tank 100, and the oil inlet pipe 210 is connected to the third oil port 530. Figure 3As shown, the first oil port 510 is port A, the second oil port 520 is port B, and the third oil port 530 is port C. The flushing valve 500 has three positions. Figure 3 Taking the position in as an example, springs are provided on the left and right sides of the flushing valve 500. When the flushing valve 500 is in the middle position, that is, the medium pressure in the first oil outlet line is close to the medium pressure in the second oil outlet line, the first oil port 510 and the second oil port 520 are not connected to the third oil port 530. At this time, no hydraulic oil in the closed hydraulic system will flow back to the oil tank 100. If the medium pressure in the first oil outlet line is greater than the medium pressure in the second oil outlet line, that is, the pressure at port A is greater than the pressure at port B, and port A and port B are The pressure difference is greater than the resistance of the spring at the B end, and the flushing valve 500 will slide to the right, so that the B port is connected to the C port, that is, the second oil port 520 is connected to the third oil port 530; correspondingly, if the medium pressure in the first oil outlet pipeline is less than the medium pressure in the second oil outlet pipeline, that is, the pressure of the B port is greater than the pressure of the A port, and the pressure difference between the B port and the A port is greater than the resistance of the spring at the A end, the flushing valve 500 will slide to the left, so that the A port is connected to the C port, that is, the first oil port 510 is connected to the third oil port 530.

[0047] It should be understood that, since hydraulic oil will enter the oil tank 100 only when there is a pressure difference between port A and port B in the current closed hydraulic system, and the pressure difference exceeds the resistance of the spring at end A or end B, it can be understood that the cooling of the hydraulic oil is passive; at the same time, the flow rate of the flushing valve 500 currently used is relatively small, so the hydraulic oil cooled by the cooler 200 is relatively small, and the effect of overall lowering the temperature of the hydraulic oil in the oil tank 100 cannot be achieved.

[0048] In order to solve the problem of rising temperature of hydraulic oil in a closed hydraulic system under high flow, high load and long-time working conditions, the hydraulic system of the first aspect of the present embodiment is provided with a unloading valve group 400, and the hydraulic oil in the oil tank 100 is pumped to the cooler 200 by utilizing the open pump 300 of the open hydraulic system, thereby realizing active cooling of the hydraulic oil in the oil tank 100, and further reducing the temperature of the hydraulic oil in the oil tank 100, thereby reducing the temperature of the hydraulic oil replenished by the oil replenishment pump to the closed hydraulic system, thereby reducing the overall oil temperature of the closed hydraulic system, and avoiding the increase of the hydraulic oil temperature of the closed hydraulic system affecting the service life of the hydraulic equipment.

[0049] In the embodiment of the utility model, the open hydraulic system includes an open pump 300 and an unloading valve group 400, the open pump 300 has an oil suction pipe 310 and an oil outlet pipe 320, the oil suction pipe 310 is connected to the oil tank 100; the unloading valve group 400 has a first interface 401 and a second interface 402, the first interface 401 is connected to the oil outlet pipe 320, and the second interface 402 is connected to the oil inlet pipe 210; the unloading valve group 400 has an energized state and a de-energized state, the unloading valve group 400 in the de-energized state is connected to the oil outlet pipe 320 and the oil inlet pipe 210 to circulate and cool the oil in the oil tank 100; the unloading valve group 400 in the energized state cuts off the connection between the oil outlet pipe 320 and the oil inlet pipe 210. The hydraulic system also includes a control component, the control component is used to control the unloading valve group 400 to switch between the energized state and the de-energized state. Specifically, as can be seen from the above, the open hydraulic system has two groups of open pumps 300. In the auxiliary working condition, the full flow of the two groups of open pumps 300 is required only when the reduction gear box is rapidly advanced or reversed. Therefore, in the non-rapid reverse or advanced working condition, one of the groups of open pumps 300 can be used to pump the hydraulic oil in the oil tank 100 to the cooler 200; then it can be imagined that in the non-rapid reverse or advanced working condition, the control component cuts off the power supply of the unloading valve group 400, so that the unloading valve group 400 is in a power-off state to circulate and cool the hydraulic oil in the oil tank 100; when the reduction gear box is rapidly advanced or reversed, the control component supplies power to the unloading valve group 400, so that the unloading valve group 400 is in a power-on state, so that both groups of open pumps 300 are used to supply hydraulic oil to the auxiliary equipment.

[0050] In the embodiment of the present utility model, the unloading valve group 400 includes a differential valve 410 and a first oil pipe 430. The two ends of the first oil pipe 430 are respectively connected to the first interface 401 and the second interface 402. The differential valve 410 is arranged on the first oil pipe 430 to control the on-off of the first oil pipe 430. Figure 1 As shown, the first interface 401 is the P port, the second interface 402 is the T port, and the second interface 402 is connected to the oil inlet pipe 210 of the cooler 200; the first oil pipe 430 is divided into two sections by the differential valve 410, the first section is the P-P1 section, and the second section is the DT section. When the P1 port is connected to the D port, the first interface 401 and the second interface 402 are connected, and the open pump 300 can pump the hydraulic oil in the oil tank 100 to the cooler 200.

[0051] In the embodiment of the present utility model, the differential valve 410 includes a housing and a piston 412 slidably mounted in the housing. The two ends of the piston 412 form a first chamber 413 and a second chamber 414 with the inner wall of the housing respectively. The pressure difference between the first chamber 413 and the second chamber 414 pushes the rod piston 412 to slide, thereby realizing the on-off of the first oil pipe 430. For details, refer to Figure 1 , Figure 2As shown, a spring is provided in the second chamber 414, and the spring pushes the piston 412 downward. If the piston 412 is at the lowest position, the P1 port and the D port are not connected. Only when the piston 412 rises and compresses the spring, the P1 port is connected to the D port.

[0052] Further, in the embodiment of the present utility model, the unloading valve assembly 400 further includes a control valve 420 and a second oil pipe 440, both ends of the second oil pipe 440 are respectively connected to the first interface 401 and the control valve 420, and an intermediate pipe 460 is provided between the control valve 420 and the second chamber 414; specifically, the control assembly is electrically connected to the control valve 420, and the control valve 420 has two positions, which are described as the first position and the second position for ease of understanding. Figure 1 The control valve 420 shown is in the first position, at which time the P2 port and the M port are connected, the L port and the N port are connected, and the unloading valve group 400 is in a power-off state; when the control valve 420 moves to the right to the second position, the P2 port and the N port are unidirectionally connected, and the L port and the M port are unidirectionally connected, and the unloading valve group 400 is in a power-on state.

[0053] In the embodiment of the utility model, an overflow pipe 450 is further included, and the two ends of the overflow pipe 450 are respectively connected to the control valve 420 and the oil tank 100; when the unloading valve group 400 is in a power-off state, the overflow pipe 450 is connected to the intermediate pipe 460. Specifically, the first end of the overflow pipe 450 is connected to the oil tank 100, and the second end of the overflow pipe 450 is connected to the L port. When the control valve 420 is in the first position, that is, the unloading valve group 400 is in a power-off state, the L port is connected to the N port, so the overflow pipe 450 is connected to the intermediate pipe 460, that is, the overflow pipe 450 is connected to the second chamber 414.

[0054] It should be understood that the control component includes a signal receiver and a processor. The signal receiver is used to receive the signal fed back by the hydraulic system and send it to the processor, and then the processor performs corresponding actions according to the signal received by the signal receiver. Specifically, in this embodiment, when the signal receiver receives a signal that the drilling rig wants to quickly advance or reverse the reduction gearbox and sends it to the processor, the processor will supply power to the control valve 420, so that the unloading valve group 400 switches to the powered state; when the signal receiver receives a signal that the drilling rig exits the rapid advancement or reverse lifting reduction gearbox and sends it to the processor, the processor will cut off the power supply to the control valve 420, so that the unloading valve group 400 switches to the de-energized state. Since the control component in this embodiment only performs simple logic processing, including the signal receiver and the processor, it is also a conventional method, so the specific connection method between the control components will not be described in detail in this article.

[0055] The specific working process of the unloading valve group 400 of this embodiment is as follows:

[0056] When the unloading valve group 400 is in the energized state, the first oil pipe 430 supplies oil to the first chamber 413, and the second oil pipe 440 supplies oil to the second chamber 414 through the intermediate pipe 460; at this time, the P2 port is connected to the N port, so the pressure in the first chamber 413 and the second chamber 414 is equal, but because the surface area of ​​the top of the piston 412 in contact with the hydraulic oil is greater than the surface area of ​​the bottom of the piston 412 in contact with the hydraulic oil, and a spring is also provided in the second chamber 414, the piston 412 will be in the lowest position at this time, cutting off the connection between the P1 port and the D port; it can be imagined that the hydraulic oil supplied by the open pump 300 to the unloading valve group 400 cannot circulate at this time, so the two starting pump groups are used to supply hydraulic oil to the auxiliary equipment, that is, the hydraulic oil in the oil tank 100 cannot be cooled, and at this time, the closed hydraulic system only has the hydraulic oil that enters the cooler 200 through the flushing valve 500 and flows back to the oil tank 100;

[0057] When the unloading valve group 400 is in a power-off state, the first oil pipe 430 supplies oil to the first chamber 413, and the second oil pipe 440 is not connected to the intermediate pipe 460, that is, the hydraulic oil at the P port will enter the second chamber 414 through P1, and the second chamber 414 will be connected to the oil tank 100 through the intermediate pipe 460 and the overflow pipe 450. At this time, the piston 412 will be pushed up to the top position, so that the P1 port and the D port are connected, and the hydraulic oil supplied by the open pump 300 will pass through the D port to the T port, and then to the oil inlet pipe 210 of the cooler 200, so as to realize the circulation cooling of the hydraulic oil in the oil tank 100.

[0058] In the embodiment of the present utility model, the cooler 200 is a water-cooled cooler 200, but a suitable cooler 200 may also be selected according to actual conditions.

[0059] According to the hydraulic system of the embodiment of the utility model, a unloading valve group 400 is provided, and the unloading valve group 400 can connect the oil outlet pipe 320 of the open pump 300 and the oil inlet pipe 210 of the cooler 200, so that the open pump 300 can be used to actively circulate and cool the hydraulic oil in the oil tank 100, thereby effectively reducing the temperature of the hydraulic oil in the oil tank 100, and further reducing the temperature of the hydraulic oil replenished into the closed hydraulic system by the oil replenishment pump, thereby reducing the operating temperature in the closed hydraulic system and improving the service life of the hydraulic components.

[0060] The skylight drilling rig of the second embodiment of the utility model adopts the above-mentioned hydraulic system, so that the skylight drilling rig can actively circulate and cool the hydraulic oil in the oil tank 100, thereby keeping the hydraulic oil at a relatively low temperature, extending the service life of the hydraulic equipment, and making the drilling rig suitable for large flow, high load, and long-term working conditions.

[0061] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0062] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A hydraulic system, characterized in that: include: tank; A cooler having an oil inlet pipe and an oil drain pipe, wherein the oil drain pipe is connected to the oil tank; An open pump having an oil suction pipe and an oil discharge pipe, wherein the oil suction pipe is connected to the oil tank; The unloading valve group has a first interface and a second interface, wherein the first interface is communicated with the oil outlet pipe, and the second interface is communicated with the oil inlet pipe; the unloading valve group has an energized state and a de-energized state, and the unloading valve group in the de-energized state is communicated with the oil outlet pipe and the oil inlet pipe to circulate and cool the oil in the oil tank; The unloading valve group in the energized state cuts off the connection between the oil outlet pipe and the oil inlet pipe; A control component is used to control the unloading valve group to switch between the energized state and the de-energized state.

2. The hydraulic system according to claim 1, characterized in that: The unloading valve group includes a differential valve and a first oil pipe. Two ends of the first oil pipe are respectively connected to the first interface and the second interface. The differential valve is arranged on the first oil pipe to control the on-off of the first oil pipe.

3. The hydraulic system according to claim 2, characterized in that: The differential valve includes a housing and a piston slidably installed in the housing, and the two ends of the piston respectively form a first chamber and a second chamber with the inner wall of the housing. The pressure difference between the first chamber and the second chamber is used to push the piston to slide, thereby realizing the opening and closing of the first oil pipe.

4. The hydraulic system according to claim 3, characterized in that: The unloading valve group further includes a control valve and a second oil pipe, the two ends of the second oil pipe are respectively connected to the first interface and the control valve, and an intermediate pipe is provided between the control valve and the second chamber; When the unloading valve group is in an energized state, the first oil pipe supplies oil to the first chamber, and the second oil pipe supplies oil to the second chamber through the intermediate pipe; When the unloading valve group is in a power-off state, the first oil pipe supplies oil to the first chamber, and the second oil pipe is not connected to the intermediate pipe.

5. The hydraulic system according to claim 4, characterized in that: The control component is electrically connected to the control valve.

6. The hydraulic system according to claim 4, characterized in that: It also includes an overflow pipe, both ends of which are connected to the control valve and the oil tank respectively; when the unloading valve group is in a power-off state, the overflow pipe is connected to the intermediate pipe.

7. The hydraulic system according to claim 1, characterized in that: It also includes a closed pump and a flushing valve, the closed pump has a first oil discharge pipeline and a second oil discharge pipeline, the flushing valve is provided with a first oil port, a second oil port and a third oil port, the first oil port is communicated with the first oil discharge pipeline, the second oil port is communicated with the second oil discharge pipeline, and the third oil port is communicated with the oil inlet pipe; If the medium pressure in the first oil discharge pipeline is greater than the medium pressure in the second oil discharge pipeline, the second oil port is connected to the third oil port; If the medium pressure in the first oil discharge pipeline is lower than the medium pressure in the second oil discharge pipeline, the first oil port is communicated with the third oil port.

8. The hydraulic system according to claim 7, characterized in that: The system also includes an oil replenishing pump, which is used to replenish hydraulic oil into the hydraulic system.

9. The hydraulic system according to claim 1, characterized in that: The cooler is a water-cooled cooler.

10. A raise boring machine, characterized in that: A hydraulic system as claimed in any one of claims 1 to 9 is used.

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