Hydraulic system for bypass control of rotary motor of raise boring machine

Abstract

The utility model discloses a hydraulic system for bypass control of a rotary motor of a raise boring machine, which relates to the technical field of hydraulic control and comprises a hydraulic motor component, an oil tank, a main oil pump, a control valve group and a backpressure regulating valve group. The hydraulic motor assembly is connected with a working oil pipe set and an oil drainage pipe set. The oil tank is used for storing hydraulic oil; the main oil pump is connected with the oil tank and used for conveying hydraulic oil in the oil tank into the working oil pipe set. The control valve set is arranged on the working oil pipe set and has a first state enabling the hydraulic motor assembly to operate at the maximum rotating speed and a second state enabling the hydraulic motor assembly to operate at the maximum torque. When the control valve set is in the first state, the back pressure adjusting valve set increases the pressure in the oil drainage pipe set, and when the control valve set is in the second state, the back pressure adjusting valve set reduces the pressure in the oil drainage pipe set. Heat generated when the hydraulic motor assembly works at the maximum rotating speed can be reduced, and the working efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of hydraulic control, in particular to a hydraulic system for bypass control of a rotary motor of a raise boring machine. Background Art

[0002] As an important construction machinery in mining machinery, the shaft boring machine has been widely used in various shaft and tunnel construction in mine construction. Its mechanical application has the characteristics of long working time, heavy workload and harsh working environment.

[0003] The main working mechanism of the raise drilling rig series equipment is the rotary system, which cooperates with the propulsion system to rotate the drill rod while applying pressure to the rock surface, so as to achieve the purpose of fast feeding, high-efficiency drilling and hole expansion. The construction of the raise drilling rig is generally divided into pilot hole operation and hole expansion operation. During the pilot hole operation, the raise drilling rig uses a roller drill bit to open a hole with a diameter of 195-350mm. The torque and pressure required to open the pilot hole are very small, and the higher the speed, the faster the footage speed during the pilot hole. At the same time, the high speed can better ensure the accuracy of the pilot hole. The hole expansion operation is opposite to the pilot hole. After the pilot hole is opened, the roller drill bit at the front end of the drill rod is replaced with a cutter head, and then the drill rig starts to pull the cutter head back along the pilot hole to expand the pilot hole into a hole of 1000-6000mm. Large torque and pressure are required for hole expansion. Under constant power, the speed provided by the rotary system is relatively small at this time. Therefore, the hydraulic motor system is required to work in two output modes. However, the hydraulic motor in the prior art requires a certain return oil back pressure to reduce abnormal noise when outputting at maximum torque. The existence of return oil back pressure when outputting at maximum speed will aggravate the heating of the motor, increase the risk of hydraulic oil leakage, and also have a negative impact on the working efficiency of the motor. 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 provides a hydraulic system for bypass control of a slewing motor of a raise boring machine, which can reduce the heat generated when the hydraulic motor assembly works at the maximum speed and improve the working efficiency.

[0005] A hydraulic system for bypass control of a rotary motor of a raise borer according to an embodiment of the first aspect of the present utility model includes: a hydraulic motor assembly, an oil tank, a main oil pump, a control valve group, and a back pressure regulating valve group. The hydraulic motor assembly is connected with a working oil pipe group and a drain oil pipe group; the oil tank is used for storing hydraulic oil; the main oil pump is connected with the oil tank, and the main oil pump is used for pressurizing the hydraulic oil in the oil tank and then conveying it into the working oil pipe group; the control valve group is arranged on the working oil pipe group and is used for controlling the flow rate of the hydraulic oil conveyed from the working oil pipe group to the hydraulic motor assembly. The control valve group has a first state for enabling the hydraulic motor assembly to operate at the maximum speed and a second state for enabling the hydraulic motor assembly to operate at the maximum torque; the back pressure regulating valve group is arranged between the drain oil pipe group and the oil tank, and the hydraulic oil in the drain oil pipe group flows back to the oil tank through the back pressure regulating valve group. When the control valve group is in the first state, the back pressure regulating valve group increases the resistance to the passing hydraulic oil to increase the pressure in the drain oil pipe group. When the control valve group is in the second state, the back pressure regulating valve group reduces the resistance to the passing hydraulic oil to reduce the pressure in the drain oil pipe group.

[0006] A hydraulic system for bypass control of a rotary motor of a raise borer according to an embodiment of the present utility model has at least the following beneficial effects: By adding a back pressure regulating valve group to control the pressure in the drain oil pipe group, the two working states of the hydraulic motor assembly are effectively taken into account. Compared with a hydraulic system that cannot adjust the pressure in the drain oil pipe group, it has the technical effects of improving the working efficiency of the hydraulic motor assembly and reducing the heat generated during the operation of the hydraulic motor assembly.

[0007] According to some embodiments of the present utility model, the back pressure regulating valve group includes a back pressure valve and a stop valve connected in parallel. The back pressure valve is used for establishing a back pressure in the drain oil pipe group to increase the pressure in the drain oil pipe group. When the control valve group is in the first state, the stop valve is closed. When the control valve group is in the second state, the stop valve is opened.

[0008] According to some embodiments of the present utility model, the back pressure regulating valve group includes a back pressure valve and a two-position three-way directional control valve. The inlet of the two-position three-way directional control valve is connected with the drain oil pipe group. The two outlets of the two-position three-way directional control valve are respectively connected with the inlet of the back pressure valve and the oil tank. The outlet of the back pressure valve is communicated with the oil tank.

[0009] According to some embodiments of the present utility model, the back pressure valve is selected from one of a check valve, a relief valve, a throttle valve, and a sequence valve.

[0010] According to some embodiments of the present utility model, the hydraulic motor assembly includes a freewheel motor and a non-freewheel motor. When the freewheel motor and the non-freewheel motor both operate in a full-displacement mode, the hydraulic motor assembly operates at maximum torque. When the freewheel motor is in a freewheel state and does not operate, and the non-freewheel motor operates in a half-displacement mode, the hydraulic motor assembly operates at maximum speed.

[0011] According to some embodiments of the present utility model, the control valve group includes a reversing valve and a freewheel valve. The reversing valve is used to control the switching of the non-freewheel motor between full-displacement operation and half-displacement operation, and the freewheel valve is used to control the switching of the freewheel motor between operation and non-operation.

[0012] According to some embodiments of the present utility model, the reversing valve and the freewheel valve are hydraulically controlled valves.

[0013] According to some embodiments of the present utility model, the freewheel valve is connected to the fuel tank through a pressure reducing valve.

[0014] According to some embodiments of the present utility model, the hydraulic motor assembly is connected to a flushing oil source.

[0015] According to some embodiments of the present utility model, an accumulator is provided at the oil inlet of the hydraulic motor assembly.

[0016] A hydraulic system for bypass control of a rotary motor of a raise borer according to an embodiment of the present utility model has at least the following beneficial effects:

[0017] (1) By adding a back pressure regulating valve group to control the pressure in the drain pipe group, the two working states of the hydraulic motor assembly are effectively balanced. Compared with a hydraulic system that cannot adjust the pressure in the drain pipe group, it has the technical effects of improving the working efficiency of the hydraulic motor assembly and reducing the heat generated during the operation of the hydraulic motor assembly;

[0018] (2) A stop valve or a two-position three-way reversing valve can be added to the existing hydraulic system to achieve the function of adjusting the pressure in the drain pipe group;

[0019] (3) By combining the freewheel motor and the non-freewheel motor, it can be flexibly adjusted according to specific working requirements, which can not only improve the working efficiency, but also ensure the accuracy and safety of the operation.

[0020] The additional aspects and advantages of the present utility model will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present utility model. Description of the Drawings

[0021] The following further describes the present utility model in conjunction with the drawings and embodiments, where:

[0022] Figure 1 It is a schematic structural diagram of the first embodiment of the present utility model;

[0023] Figure 2 It is a schematic structural diagram of the second embodiment of the present utility model.

[0024] Reference numerals in the drawings:

[0025] Hydraulic motor assembly 100, freewheel motor 110, non-freewheel motor 120;

[0026] Working oil pipe group 200;

[0027] Drain oil pipe group 300;

[0028] Fuel tank 400;

[0029] Main oil pump 500;

[0030] Control valve group 600, reversing valve 610, freewheel valve 620;

[0031] Back pressure regulating valve group 700, back pressure valve 710, stop valve 720, two-position three-way reversing valve 730;

[0032] Pressure reducing valve 800;

[0033] Flushing oil source 900, flushing pipeline 901, accumulator 910. Detailed implementation manners

[0034] The embodiments of the present utility model will be described in detail below. The examples of the embodiments are shown in the drawings, in which the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present utility model and should not be construed as a limitation of the present utility model.

[0035] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by terms such as up and down, etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model 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 should not be construed as a limitation of the present utility model.

[0036] In the description of the present utility model, "a plurality of" means more than two. If there is a description of first and second, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the sequence of the indicated technical features.

[0037] In the description of the present utility model, unless otherwise clearly defined, terms such as "set", "installed", "connected", etc. should be understood in a broad sense, and those skilled in the relevant technical field can reasonably determine the specific meanings of the above terms in the present utility model in combination with the specific content of the technical solution.

[0038] Refer to Figure 1As shown in the figure, a hydraulic system for bypass control of a rotary motor of a raise boring machine according to the first embodiment of the present utility model includes: a hydraulic motor assembly 100, an oil tank 400, a main oil pump 500, a control valve group 600, and a back pressure regulating valve group 700. The hydraulic motor assembly 100 is connected with a working oil pipe group 200 and a drain oil pipe group 300; the function of the hydraulic motor assembly 100 on the raise boring machine is to use high-pressure hydraulic oil as a power source to drive the drill bit to rotate. The oil tank 400 is used to store hydraulic oil; the main oil pump 500 is connected with the oil tank 400, and the main oil pump 500 is used to pressurize the hydraulic oil in the oil tank 400 and then transport it to the working oil pipe group 200; the main oil pump 500 is a piston pump. The control valve group 600 is arranged on the working oil pipe group 200 and is used to control the flow rate of the hydraulic oil transported from the working oil pipe group 200 to the hydraulic motor assembly 100. The control valve group 600 controls the operation mode of the hydraulic motor assembly 100 by controlling the hydraulic oil flowing to the hydraulic motor assembly 100. The control valve group 600 has a first state in which the hydraulic motor assembly 100 operates at the maximum speed and a second state in which the hydraulic motor assembly 100 operates at the maximum torque; the hydraulic motor assembly 100 is a prior art, and the torque and speed of the hydraulic motor assembly 100 are inversely proportional. In the prior art, when the raise boring machine performs a pilot hole operation, since the size of the pilot hole is generally 195 mm to 350 mm, the torque and pressure required for drilling are very small. The higher the speed of the hydraulic motor assembly 100, the faster the speed during the pilot hole operation, and at the same time, a higher speed can better ensure the accuracy during the pilot hole operation. Therefore, the hydraulic motor assembly 100 operates at the maximum speed during the pilot hole operation. After the pilot hole operation is completed, the roller bit at the front end of the drill pipe is replaced with a cutter head, and then the raise boring machine starts to pull the cutter head back along the pilot hole to expand the pilot hole into a hole with a size of 1000 mm to 6000 mm. When the raise boring machine performs the reaming operation, the hydraulic motor assembly 100 needs to output a large torque and pressure. Therefore, the hydraulic motor assembly 100 operates at the maximum torque during the reaming operation. The back pressure regulating valve group 700 is arranged between the drain oil pipe group 300 and the oil tank 400. The hydraulic oil in the drain oil pipe group 300 returns to the oil tank 400 through the back pressure regulating valve group 700. When the control valve group 600 is in the first state, the back pressure regulating valve group 700 increases the resistance to the passing hydraulic oil to increase the pressure in the drain oil pipe group 300. When the control valve group 600 is in the second state, the back pressure regulating valve group 700 reduces the resistance to the passing hydraulic oil to reduce the pressure in the drain oil pipe group 300. In the prior art, the characteristics of the hydraulic motor assembly 100 are: when operating at the maximum speed, a certain pressure needs to exist in the drain oil pipe group 300, that is, back pressure needs to be provided for the return oil to prevent abnormal noise and extend the service life of the hydraulic motor assembly 100. When operating at the maximum torque, the pressure in the drain oil pipe group 300 needs to be as low as possible to improve the working efficiency of the hydraulic motor assembly 100 and reduce the heat generated during the operation of the hydraulic motor assembly 100.The pressure in the drain pipe group 300 is controlled by adding a back pressure regulating valve group 700, effectively taking into account the two working states of the hydraulic motor assembly 100. Compared with the prior art hydraulic system that cannot adjust the pressure in the drain pipe group 300, it has the technical effects of improving the working efficiency of the hydraulic motor assembly 100 and reducing the heat generated during the operation of the hydraulic motor assembly 100. It can also extend the service life of the hydraulic motor assembly and reduce the equipment failure rate.

[0039] Referring to Figure 1 As shown, in the first embodiment of the present invention, the back pressure regulating valve group 700 includes a parallel-connected back pressure valve 710 and a globe valve 720. The inlet of the back pressure valve 710 and the inlet of the globe valve 720 are both connected to the drain pipe group 300, and the outlet of the back pressure valve 710 and the outlet of the globe valve 720 are both connected to the oil tank 400. The back pressure valve 710 is used to establish a back pressure in the drain pipe group 300 and increase the pressure in the drain pipe group 300. When the control valve group 600 is in the first state, the globe valve 720 is closed, and the hydraulic oil flows back to the oil tank 400 through the back pressure valve 710. At this time, due to the action of the back pressure valve 710, a pressure of 0.5 MPa to 1.5 MPa is generated in the drain pipe group 300 to form a back pressure, preventing abnormal noise and extending the service life of the hydraulic motor assembly 100. When the control valve group 600 is in the second state, the globe valve 720 is opened. Since the pressure drop of the hydraulic oil when passing through the globe valve 720 is very small, the hydraulic oil no longer passes through the back pressure valve 710 but flows to the oil tank 400 through the globe valve 720, effectively reducing the pressure in the drain pipe group 300. After the globe valve 720 is opened, the pressure in the drain pipe group 300 can be maintained below 0.15 MPa to improve the working efficiency of the hydraulic motor assembly 100 and reduce the heat generated during the operation of the hydraulic motor assembly 100.

[0040] Referring to Figure 2As shown, in the second embodiment of the present utility model, the backpressure regulating valve group 700 includes a backpressure valve 710 and a two-position three-way directional control valve 730. The inlet of the two-position three-way directional control valve 730 is connected to the drain pipe group 300. The two outlets of the two-position three-way directional control valve 730 are respectively connected to the inlet of the backpressure valve 710 and the oil tank 400. The outlet of the backpressure valve 710 communicates with the oil tank 400. By switching the two-position three-way directional control valve 730, the hydraulic oil is switched between directly entering the oil tank 400 and entering the oil tank 400 through the backpressure valve 710. When the two-position three-way directional control valve 730 directly connects the oil tank 400 and the drain pipe group 300, the pressure drop of the hydraulic oil passing through the two-position three-way directional control valve 730 is very small, effectively reducing the pressure in the drain pipe group 300, preventing abnormal noise and extending the service life of the hydraulic motor assembly 100. When the two-position three-way directional control valve 730 connects the backpressure valve 710 and the drain pipe group 300, due to the function of the backpressure valve 710, a pressure of 0.5 MPa - 1.5 MPa is generated in the drain pipe group 300 to form backpressure, preventing abnormal noise and extending the service life of the hydraulic motor assembly 100.

[0041] Referring to Figure 1 and Figure 2 shown, it can be understood that the backpressure valve 710 is selected from one of a check valve, a relief valve, a throttle valve, and a sequence valve. When the backpressure valve 710 is a check valve, the check valve is set to only allow the hydraulic oil to flow from the drain pipe group 300 to the oil tank 400, and the opening pressure of the check valve is set to 0.5 MPa to 1.5 MPa. When the backpressure valve 710 is a relief valve or a sequence valve, its opening pressure is set to 0.5 MPa to 1.5 MPa. When a throttle valve is selected, in the case of a small flow rate of the hydraulic oil, the pressure in the drain pipe group 300 is also small. Therefore, in order to make the drain pipe group 300 have a certain pressure at a small flow rate, a throttle valve that can adjust the opening degree, that is, a regulating valve, can be used. The opening degree of the throttle valve is reduced at a small flow rate to increase the pressure in the drain pipe group 300. The specific structures of the check valve, the relief valve, the throttle valve, and the sequence valve are prior art, so they will not be described in detail. Figure 1 The hydraulic system shown in the figure is for the case where the backpressure valve is a check valve. Considering the equipment volume and cost, the backpressure valve is preferably a check valve with a lower cost.

[0042] Referring to Figure 1As shown, it can be understood that the hydraulic motor assembly 100 includes a freewheel motor 110 and a non-freewheel motor 120. When the freewheel motor 110 and the non-freewheel motor 120 operate simultaneously in full-displacement mode, the hydraulic motor assembly 100 operates at maximum torque. When the freewheel motor 110 is in the freewheel state and does not operate while the non-freewheel motor 120 operates in half-displacement mode, the hydraulic motor assembly 100 operates at maximum speed. Since the flow rate of the hydraulic oil output by the main oil pump per minute is constant, stopping the freewheel motor 110 and leaving only the non-freewheel motor 120 to operate alone will increase the flow rate through the non-freewheel motor 120 and increase the speed of the non-freewheel motor 120. The main advantage of the freewheel motor 110 is that it can achieve resistance-free rotation under specific conditions, which is particularly important for improving work efficiency and saving working time. The non-freewheel motor 120 provides more precise and controllable operation and is suitable for application scenarios that require precise control and positioning. Combining the freewheel motor 110 and the non-freewheel motor 120 can be flexibly adjusted according to specific work requirements, which can not only improve work efficiency but also ensure the accuracy and safety of operation. The installation method and specific structure of the freewheel motor 110 and the non-freewheel motor 120 are prior art and will not be described in detail. The drain pipe group 300 is connected to the oil outlet of the freewheel motor 110 and the oil outlet of the non-freewheel motor 120 to receive the discharged hydraulic oil.

[0043] Referring to Figure 1 As shown, it can be understood that the control valve group 600 includes a reversing valve 610 and a freewheel valve 620. The reversing valve 610 is used to control the non-freewheel motor 120 to switch between full-displacement mode and half-displacement mode. The reversing valve 610 is connected to the control port of the non-freewheel motor 120. When the reversing valve 610 inputs hydraulic oil to the control port of the non-freewheel motor 120, it can control the displacement of the non-freewheel motor 120, that is, control the speed of the non-freewheel motor 120. The freewheel valve 620 is used to control the freewheel motor 110 to switch between operation and non-operation. When the freewheel motor 110 is not operating, it is in the freewheel state and can achieve resistance-free rotation. The specific structure and connection method of the reversing valve 610 and the freewheel valve 620 are prior art and will not be described in detail.

[0044] Referring to Figure 1 As shown, it can be understood that the reversing valve 610 is an electrically controlled valve, and the freewheel valve 620 is a combination of a hydraulically controlled valve and an electrically controlled valve. The hydraulically controlled valve has the advantages of stable and reliable performance and simple and compact structure. In the event of a sudden accident and power interruption, the accumulator 910 can still be used for one or several power operations.

[0045] Referring to Figure 1As shown, it can be understood that the overrunning clutch valve 620 is connected to the oil tank 400 through a pressure reducing valve 800, effectively preventing the hydraulic oil pressure in the oil tank 400 from being too high and causing damage to the oil tank 400.

[0046] Referring to Figure 1 As shown, it can be understood that the hydraulic motor assembly 100 is connected to a flushing oil source 900. The flushing oil source 900 is connected to the flushing oil ports of the overrunning clutch motor 110 and the non-overrunning clutch motor 120 through a flushing pipeline 901. During operation, due to various reasons such as friction and corrosion, the hydraulic motor assembly 100 will generate impurities such as metal chips and sludge. If these impurities are not removed in time, they will have a negative impact on the performance and service life of the hydraulic motor. The function of the flushing oil source 900 is to introduce clean oil fluid and carry away the impurities in the hydraulic motor assembly 100 through flushing to keep the hydraulic motor assembly 100 clean.

[0047] Referring to Figure 1 As shown, it can be understood that an accumulator 910 is provided at the oil inlet of the hydraulic motor assembly 100. The accumulator 910 has the functions of absorbing hydraulic shock and providing power in an emergency to ensure the safety of the hydraulic system.

[0048] Working principle: The main oil pump 500 transports the hydraulic oil in the oil tank 400 to the working oil pipe group 200. The reversing valve 610 and the overrunning clutch valve 620 control the overrunning clutch motor 110 and the non-overrunning clutch motor 120 by adjusting and distributing the hydraulic oil in the working oil pipe group 200. When the reversing valve 610 and the overrunning clutch valve 620 are de-energized, the control valve group 600 is in the first state, and the hydraulic motor assembly 100 operates at the maximum speed. The check valve 720 is closed, and the hydraulic oil flows back to the oil tank 400 through the back pressure valve 710. At this time, due to the function of the back pressure valve 710, a back pressure is formed in the drain pipe group 300 to prevent abnormal noise of the hydraulic motor assembly 100 and extend the service life of the hydraulic motor assembly 100. When the reversing valve 610 and the overrunning clutch valve 620 are energized, the control valve group 600 is in the second state, and the hydraulic motor assembly 100 operates at the maximum torque. The check valve 720 is opened. Since the pressure drop of the hydraulic oil passing through the check valve 720 is very small, the hydraulic oil no longer passes through the back pressure valve 710 but flows to the oil tank 400 through the check valve 720, effectively reducing the pressure in the drain pipe group 300 to improve the working efficiency of the hydraulic motor assembly 100 and reduce the heat generated during the operation of the hydraulic motor assembly 100.

[0049] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge scope of those of ordinary skill in the art.

Claims

1. A hydraulic system for bypass control of a slewing motor of a raise boring machine, characterized in that: include: A hydraulic motor assembly (100) is connected to a working oil pipe assembly (200) and an oil drain pipe assembly (300); An oil tank (400) for storing hydraulic oil; A main oil pump (500) is connected to the oil tank (400), and the main oil pump (500) is used to pressurize the hydraulic oil in the oil tank (400) and then transport it to the working oil pipe group (200); a control valve group (600) arranged on the working oil pipe group (200) and used for controlling the flow of hydraulic oil delivered from the working oil pipe group (200) to the hydraulic motor assembly (100), the control valve group (600) having a first state for making the hydraulic motor assembly (100) run at a maximum speed and a second state for making the hydraulic motor assembly (100) run at a maximum torque; A back pressure regulating valve group (700), wherein the back pressure regulating valve group (700) is arranged between the oil drain pipe group (300) and the oil tank (400), and the hydraulic oil in the oil drain pipe group (300) flows back to the oil tank (400) through the back pressure regulating valve group (700); when the control valve group (600) is in a first state, the back pressure regulating valve group (700) increases the resistance to the hydraulic oil passing through so as to increase the pressure in the oil drain pipe group (300); when the control valve group (600) is in a second state, the back pressure regulating valve group (700) reduces the resistance to the hydraulic oil passing through so as to reduce the pressure in the oil drain pipe group (300).

2. The hydraulic system for bypass control of a slewing motor of a raise boring machine according to claim 1, characterized in that: The back pressure regulating valve group (700) comprises a back pressure valve (710) and a stop valve (720) connected in parallel. The back pressure valve (710) is used to establish back pressure in the oil drain pipe group (300) to increase the pressure in the oil drain pipe group (300). When the control valve group (600) is in a first state, the stop valve (720) is closed. When the control valve group (600) is in a second state, the stop valve (720) is opened.

3. The hydraulic system for bypass control of a slewing motor of a raise boring machine according to claim 1, characterized in that: The back pressure regulating valve group (700) comprises a back pressure valve (710) and a two-position three-way reversing valve (730), wherein the inlet of the two-position three-way reversing valve (730) is connected to the oil drain pipe group (300), and the two outlets of the two-position three-way reversing valve (730) are respectively connected to the inlet of the back pressure valve (710) and the oil tank (400), and the outlet of the back pressure valve (710) is in communication with the oil tank (400).

4. The hydraulic system for bypass control of a slewing motor of a raise boring machine according to claim 2 or 3, characterized in that: The back pressure valve (710) is selected from one of a one-way valve, a relief valve, a throttle valve and a sequence valve.

5. The hydraulic system for bypass control of a slewing motor of a raise boring machine according to claim 4, characterized in that: The hydraulic motor assembly (100) comprises a freewheel motor (110) and a non-freewheel motor (120); when the freewheel motor (110) and the non-freewheel motor (120) are operated in full displacement mode at the same time, the hydraulic motor assembly (100) operates at maximum torque; when the freewheel motor (110) is in a freewheel state and does not operate and the non-freewheel motor (120) is operated in half displacement mode, the hydraulic motor assembly (100) operates at maximum speed.

6. The hydraulic system for bypass control of a slewing motor of a raise boring machine according to claim 5, characterized in that: The control valve group (600) comprises a reversing valve (610) and a freewheel valve (620), wherein the reversing valve (610) is used to control the non-freewheel motor (120) to switch between full-displacement operation and half-displacement operation, and the freewheel valve (620) is used to control the freewheel motor (110) to switch between operation and non-operation.

7. The hydraulic system for bypass control of a slewing motor of a raise boring machine according to claim 6, characterized in that: The reversing valve (610) is an electrically controlled valve, and the free wheel valve (620) is a combination of a hydraulically controlled valve and an electrically controlled valve.

8. The hydraulic system for bypass control of a slewing motor of a raise boring machine according to claim 7, characterized in that: The free wheel valve (620) is connected to the oil tank (400) via a pressure reducing valve (800).

9. The hydraulic system for bypass control of a slewing motor of a raise boring machine according to claim 1, characterized in that: The hydraulic motor assembly (100) is connected to a flushing oil source (900).

10. The hydraulic system for bypass control of a slewing motor of a raise boring machine according to claim 1, characterized in that: An accumulator (910) is provided at the oil inlet of the hydraulic motor assembly (100).

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