Proportional pressure limiting valve group for shield tunneling machine propelling system

Abstract

The utility model provides a proportional pressure-limiting valve group for a shield tunneling machine propelling system, which comprises a proportional pressure-limiting valve arranged in a main oil way, an oil inlet of a pilot-operated overflow valve is connected with an oil inlet of the main oil way, and an oil inlet of an electromagnetic directional valve is connected with a control oil port of the pilot-operated overflow valve. An oil inlet of the proportional overflow valve is connected with a working oil port of the electromagnetic reversing valve, and oil return ports of the pilot-operated overflow valve, the electromagnetic reversing valve and the proportional overflow valve are connected to an oil return port of the main oil way. When the electromagnetic directional valve is not electrified, the maximum pressure of the propulsion system is limited not to exceed a set value of the pilot-operated overflow valve; when the electromagnetic valve is electrified, the system pressure is adjusted by the proportional overflow valve according to actual application; the problems of propelling zone pressure fluctuation, pressure building of a propelling pump, no propelling speed, serious system heating and the like during propelling of the shield tunneling machine are solved, the problem that the propelling posture is uncontrollable due to large load pressure fluctuation can be avoided, propelling faults are reduced, and the system stability is guaranteed.

Description

Technical Field

[0001] The utility model relates to a shield machine, in particular to a propulsion system of a shield machine. Background Technique

[0002] At present, the commonly used propulsion pump source of the shield machine provides power for the propulsion system, the proportional pressure reducing valve is adjusted to control the pressure of each partition, and the oil cylinder telescopic control valve group controls the action of the oil cylinder. During the propulsion process, only the pressures of the upper zone, the left zone, and the right zone are controlled, and the pressure of the lower zone is not controlled and is the same as the pressure of the propulsion pump source. This propulsion method is relatively energy-saving, and the propulsion speed remains roughly unchanged. The fluctuation of the front load will be reflected in the pressure of the lower zone, resulting in the pressure fluctuation of the lower zone, which is applicable to the working conditions where the front load changes little. When the load pressure fluctuates greatly, there will be a large fluctuation range of the propulsion pump source pressure and the partition pressure, with a pressure jump of about 10 MPa, and the fluctuation speed is fast, which affects the adjustment of the propulsion attitude; if it is necessary to push the shield body forward, the total thrust needs to be equal to the resistance, that is, Fr = F1 + F2 + F3 + F4, where Fr represents the resistance, and F1 to F4 represent the thrusts of each partition. And the maximum thrust of each partition is limited. The system is protected by an overflow valve, and the overflow value is about 33 MPa. When F1, F2, and F3 are relatively small, in order to push the shield body forward, F4 (the lower zone) will be maximized passively, and the corresponding partition pressure and the propulsion pump pressure will rise passively until the corresponding partition reaches 33 MPa, and the propulsion pump source will be blocked by pressure, and the system will overflow; if Fr > F1 + F2 + F3 + F4, there will be no propulsion speed.

[0003] To solve such problems, the propulsion method is improved, the pressures of each partition are controlled, and the propulsion pump source is blocked by pressure to reach the overflow pressure, so that the pressures of each partition are kept stable. The fluctuation of the front load pressure will cause the fluctuation of the propulsion speed, and the required flow rate for the propulsion speed fluctuation is adapted by the overflow flow rate of the propulsion pump source. However, in this method, the pump has been in a high-pressure overflow state, the system generates heat seriously, the service life of the pump is reduced, and it is not suitable for long-term operation. Summary of the Invention

[0004] Object of the Invention: Aiming at the deficiencies of the prior art, the utility model provides a proportional pressure limiting valve group for the propulsion system of a shield machine, which solves the problems of pressure fluctuation in the propulsion area of the shield machine, propulsion pump pressure blocking, no propulsion speed, difficult adjustment of propulsion attitude, serious system heating, etc.

[0005] Technical Solution: A proportional pressure limiting valve group for the propulsion system of a shield machine includes a proportional pressure limiting valve arranged in the main oil circuit, and the proportional pressure limiting valve includes:

[0006] A pilot-operated overflow valve, the oil inlet of the pilot-operated overflow valve is connected to the oil inlet of the main oil circuit;

[0007] Electromagnetic reversing valve, the oil inlet of the electromagnetic reversing valve is connected to the control oil port of the pilot-operated overflow valve;

[0008] Proportional overflow valve, the oil inlet of the proportional overflow valve is connected to the working oil port of the electromagnetic reversing valve;

[0009] The oil return ports of the pilot-operated overflow valve, the electromagnetic reversing valve and the proportional overflow valve are connected to the oil return port of the main oil circuit.

[0010] Furthermore, the set overflow value of the pilot-operated overflow valve is 33 MPa.

[0011] Furthermore, the pressure setting range of the proportional overflow valve is 0 - 33 MPa.

[0012] Furthermore, the electromagnetic reversing valve is a two-position four-way solenoid valve with one working oil port closed, and the oil inlet of the proportional overflow valve is connected to the opened working oil port of the two-position four-way solenoid valve.

[0013] Furthermore, a damping hole is provided on the connecting oil path between the pilot-operated overflow valve and the electromagnetic reversing valve.

[0014] Furthermore, a control reversing valve is further included in the main oil circuit, and the control reversing valve is respectively connected to an upper-zone proportional pressure reducing valve, a lower-zone proportional pressure reducing valve, a left-zone proportional pressure reducing valve and a right-zone proportional pressure reducing valve.

[0015] Beneficial effects: When the electromagnetic reversing valve is not energized, the maximum pressure of the propulsion system is limited not to exceed the set value of the pilot-operated overflow valve; when the solenoid valve is energized, the system pressure is adjusted by the proportional overflow valve according to actual applications; it solves problems such as pressure fluctuations in the propulsion area during the tunneling machine propulsion, pressure build-up of the propulsion pump, no speed of propulsion, and serious system overheating, and can avoid the problem of uncontrollable propulsion attitude caused by large load pressure fluctuations, reduce propulsion failures, and ensure system stability. Description of the Drawings

[0016] Figure 1 It is a structural schematic diagram of the tunneling machine propulsion system;

[0017] Figure 2 It is a schematic diagram of the principle of the hydraulic proportional pressure limiting valve group of the present invention in the main oil circuit;

[0018] Figure 3 It is a schematic diagram of the hydraulic proportional pressure limiting valve group of the present invention;

[0019] Figure 4 It is a schematic diagram of the oil circuit when the solenoid valve is not energized and the oil circuit pressure has not reached the set value of the pilot-operated overflow valve;

[0020] Figure 5 It is a schematic diagram of the oil circuit when the solenoid valve is not energized and the oil circuit pressure has reached the set value of the pilot-operated overflow valve;

[0021] Figure 6 It is a schematic diagram of the oil circuit when the solenoid valve is energized and the oil circuit pressure has not reached the set value of the proportional relief valve;

[0022] Figure 7 It is a schematic diagram of the oil circuit when the solenoid valve is energized and the oil circuit pressure has reached the set value of the proportional relief valve. Specific embodiments

[0023] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the described embodiments.

[0024] For the convenience of description, first, a brief introduction to the basic principle of the shield machine is given. The shield machine is usually driven forward by the propulsion system 30. In addition, the main drive drives the cutter head 20 to rotate to excavate the soil mass, and the excavated soil mass is transported to the rear through the screw conveyor. Here, the cutter head 20 is arranged at the front end of the shield body 10, and the propulsion system 30 is arranged at the rear end of the shield body 10. The propulsion system 30 includes propulsion cylinders arranged along the circumference of the shield body 10, as Figure 1 shown.

[0025] A proportional pressure limiting valve group for the propulsion system of a shield machine includes a proportional pressure limiting valve arranged in the main oil circuit, as Figure 2 shown. The main oil circuit also includes a directional control valve, and the oil circuits controlling the directional valve are respectively connected to the upper-zone proportional pressure reducing valve, the lower-zone proportional pressure reducing valve, the left-zone proportional pressure reducing valve, the right-zone proportional pressure limiting valve, and the proportional pressure reducing valve of this embodiment.

[0026] In addition, a filter can be arranged in the main oil circuit. The filter can filter impurities in the high-pressure oil circuit to ensure the long-term normal operation of the oil circuit.

[0027] The proportional pressure limiting valve of this embodiment includes a pilot-operated relief valve 1, a solenoid directional valve 3, and a proportional relief valve 4, as Figure 3 shown. The oil inlet P1 of the pilot-operated relief valve 1 is connected to the oil inlet of the main oil circuit. The oil inlet of the solenoid directional valve 3 is connected to the control oil port of the pilot-operated relief valve 1. The oil inlet of the proportional relief valve 4 is connected to the working oil port B of the solenoid directional valve 3; the oil return ports T of the pilot-operated relief valve 1, the solenoid directional valve 3, and the proportional relief valve 4 are connected to the oil return port R of the main oil circuit. A test port MP1 can also be arranged at the oil inlet P1 to monitor the pressure value in the oil circuit through a sensor.

[0028] Exemplarily, the solenoid directional valve 3 is a two-position three-way solenoid valve. Referring to Figure 3 , it can be to block the working oil port A of the two-position four-way solenoid valve and only use the working oil port B.

[0029] Further, the set overflow value of the pilot-operated relief valve 1 is 33 MPa, and the pressure adjustment range of the proportional relief valve 4 is 0 - 33 MPa.

[0030] As Figure 4 shown, when the electromagnetic directional control valve 3 is de-energized and the pressure in the oil circuit has not reached the set overflow value of the pilot-operated relief valve 1, the pilot-operated relief valve 1 is not opened and the proportional pressure limiting valve group is not conducted.

[0031] As Figure 5 shown, when the electromagnetic directional control valve 3 is de-energized and the pressure in the oil circuit reaches the set overflow value of 33 MPa of the pilot-operated relief valve 1, the pilot-operated relief valve 1 is opened, and the high-pressure oil enters the oil return port R through the pilot-operated relief valve 1 to ensure that the oil pressure of the propulsion system does not exceed the set value of 33 MPa of the pilot-operated relief valve 1.

[0032] As Figure 6 shown, when the electromagnetic directional control valve 3 is switched to the left position, i.e., the working oil port B, the electromagnetic directional control valve 3 is energized, and when the system pressure has not reached the set value of the proportional relief valve 4, the proportional relief valve 4 is not opened.

[0033] As Figure 7 shown, when the electromagnetic directional control valve 3 is switched to the left position, i.e., the working oil port B, the electromagnetic directional control valve 3 is energized, and the proportional relief valve 4 is conducted. At this time, the system pressure depends on the proportional relief valve 4. The set pressure of the proportional relief valve 4 can be adjusted within the range of 0 - 33 MPa by current. If the system pressure exceeds the set value of the proportional relief valve 4, the spool of the proportional relief valve 4 opens, and the high-pressure oil leads to the oil return port R. At this time, the system pressure is the set pressure of the proportional relief valve 4, that is, the set pressure of the proportional relief valve 4 is the highest system pressure.

[0034] In addition, a damping hole 2 is provided on the connecting oil path between the pilot-operated relief valve 1 and the electromagnetic directional control valve 3, and the aperture of the damping hole 2 is 1 mm. The damping hole 2 can reduce the high-pressure oil flow rate passing through the electromagnetic directional control valve 3 and the proportional relief valve 4, can delay the change, reduce the oscillation, and protect the electromagnetic directional control valve 3 and the proportional relief valve 4.

[0035] In this embodiment, the pressure value of the proportional relief valve 4 of the proportional pressure limiting valve group is adjusted by current to keep the pressure of each partition consistent. Through observation, the pressure value to be adjusted can meet the normal propulsion of the shield machine, and it is concluded that this pressure is the propulsion critical value. Continue to adjust the current of the proportional relief valve 4 to reserve a thrust margin, and it is okay when the pressure value is 2 - 3 MPa greater than the critical value. Assume that the critical value during the shield machine propulsion is 14 MPa, and continue to adjust the current value to 16 or 17 MPa. The pressure of each partition is 14 MPa, and the thrusts of each partition at this pressure are F1, F2, F3, and F4. The total resistance during the shield machine propulsion is Fr. At this time, Fr = F1 + F2 + F3 + F4; continue to adjust the pressure to 16 or 17 MPa. At this time, Fr < F1 + F2 + F3 + F4, which can meet the resistance fluctuating within a certain range but does not affect the propulsion, and there is no need to repeatedly adjust the proportional relief valve 4.

[0036] As described above, although the present utility model has been shown and described with reference to specific preferred embodiments, it should not be construed as a limitation on the present utility model itself. Various changes may be made in its form and details without departing from the spirit and scope of the present utility model as defined by the appended claims.

Claims

1. A proportional pressure-limiting valve group for a shield machine propulsion system, characterized in that: The proportional pressure limiting valve is provided in the main oil circuit, and the proportional pressure limiting valve comprises: A pilot-operated relief valve, the oil inlet of the pilot-operated relief valve being connected to the oil inlet of the main oil circuit; An electromagnetic reversing valve, wherein the oil inlet of the electromagnetic reversing valve is connected to the control oil port of the pilot-operated relief valve; A proportional relief valve, wherein the oil inlet of the proportional relief valve is connected to the working oil port of the electromagnetic reversing valve; The oil return ports of the pilot-operated relief valve, the electromagnetic reversing valve and the proportional relief valve are connected to the oil return port of the main oil circuit.

2. The proportional pressure-limiting valve group for a shield machine propulsion system according to claim 1 is characterized in that: The set overflow value of the pilot-operated overflow valve is 33 MPa.

3. The proportional pressure-limiting valve group for a shield machine propulsion system according to claim 1 is characterized in that: The pressure setting range of the proportional relief valve is 0-33MPa.

4. The proportional pressure-limiting valve group for a shield machine propulsion system according to claim 1, characterized in that: The electromagnetic reversing valve is a two-position four-way electromagnetic valve with one working oil port closed, and the oil inlet of the proportional relief valve is connected to the working oil port of the two-position four-way electromagnetic valve that is opened.

5. The proportional pressure-limiting valve group for a shield machine propulsion system according to claim 1, characterized in that: A damping hole is arranged on the connecting oil path between the pilot-operated overflow valve and the electromagnetic reversing valve.

6. The proportional pressure-limiting valve group for a shield machine propulsion system according to claim 1, characterized in that: The main oil circuit also includes a control reversing valve, which is respectively connected to the upper partition proportional pressure reducing valve, the lower partition proportional pressure reducing valve, the left partition proportional pressure reducing valve and the right partition proportional pressure reducing valve.

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