JP2737560B2 - Shield excavator hydraulic system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic device for a cutter of a shield excavator for excavating a tunnel or the like.

[0002]

2. Description of the Related Art A shield excavator excavates a tunnel or the like while a cylindrical shield body 3 constituting an outer frame of the excavator 1 supports an excavation portion, as shown in FIG. Segments are continuously arranged behind the shield body 3 to support the inside of the tunnel. The shield body 3 is provided with a shield jack (not shown), which presses the already provided structure, and the shield body 3 moves forward by the reaction force.

On the front surface of the shield body 3, a cutter disk 5 for excavation is provided. Cutter disk 5
A ring gear 7 is integrally provided at the rear of the gear, and a plurality of hydraulic motors 9 mesh with the ring gear 7. The hydraulic motor 9 drives the cutter 5 to rotate by hydraulic pressure. The excavated earth and sand falls into the cutter chamber 11 and is discharged backward by the screw conveyor 13 and the belt conveyor 15.

[0006] The plurality of hydraulic motors 9 are arranged as shown in FIG.
As shown in the figure, the hydraulic pump is connected to a separate hydraulic circuit and a hydraulic pump 17 as a hydraulic pressure source. That is, in this embodiment, four hydraulic pumps 17 are provided for four hydraulic motors 9. Then, the pressure reducing valve 19 (2
00 (kg / cm ² ) and a switching valve 21.

[0005]

However, in the prior art, if any one of the four hydraulic motors 9 meshing with the ring gear 7 fails, the excavating force is reduced, making it impossible to excavate. That is, the four hydraulic motors 9 work together to obtain the required excavating force, and if one or two or more of the hydraulic motors 9 fails, the excavating force is quickly insufficient. For this reason, excavation must be temporarily stopped and the hydraulic motor must be repaired, thereby reducing the efficiency of excavation work.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and even if a part of a plurality of hydraulic motors fails, the other hydraulic motors cover insufficient digging force and continue digging. It is an object of the present invention to provide a hydraulic device of a shield excavator capable of performing the same.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a plurality of hydraulic motors that mesh with a ring gear of a cutter disk provided in a shield excavator to drive the rotation of the cutter disk. Each switching valve that bypasses the pressure fluid when each hydraulic motor fails, a gear flow divider that keeps the flow ratio of the pressure fluid sent to each hydraulic motor constant, and a hydraulic source that sends the pressure fluid through the gear flow divider It is provided with.

[0008]

When, for example, one of a plurality of hydraulic motors fails, the switching valve of the failed hydraulic motor bypasses the pressure fluid and stops using the hydraulic motor.
Regardless of whether or not this hydraulic motor is used, the pressure fluid sent to the hydraulic circuit of another cutter and the pressure sent to the hydraulic circuit of the discontinued hydraulic motor are operated by the operation of the gear flow divider. The fluid flow ratio is constant. At the same time, the pressure of the latter pressure fluid becomes almost zero, and the pressure of the former pressure fluid increases accordingly. As a result, the remaining power of the failed hydraulic motor is shifted to another hydraulic motor, so that it is possible to cover the excavating power that would have been insufficient in the past.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. The gears of the four hydraulic motors mesh with the ring gear of one cutter disk of the shield excavator to rotate the cutter disk.

[0010] Two hydraulic pumps 17 are provided in parallel,
The pressure fluid is sent to the outward path 23. A pressure reducing valve 19 is provided between the forward path 23 and the return path 25, for example, 200 (kg / cm ² ).
At this pressure, the valve opens to bypass the pressure fluid. The forward path 23 is first provided with the gear type flow divider 2.
7 is connected. The gear type flow divider 27 has a structure shown in FIGS. 2 to 4 and branches the outward path 23 into four parts. A drive gear 25 and an idle gear 27 are provided in mesh with the outgoing paths 23-1, 23-1, 23-3, and 23-4 after branching. The drive gear 25 is common to the four forward paths 23-1, 23-2, 23-3, and 23-4 after branching, and the idle gear 27 is connected to each of the forward paths 23-1 and 23-23.
2, 23-3 and 23-4 are separate and idle. Therefore, the rotation speed of each gear 25, 27 is the same, and this rotation speed is proportional to each flow rate of the pressure fluid. Therefore, the flow ratio in the four outgoing routes 23-1, 23-2, 23-3, and 23-4 after branching is always constant.

Each outgoing path 2 exiting the gear type flow divider 27
3-1, 23-2, 23-3 and 23-4 have a pressure reducing valve 29.
Are operated at a pressure of, for example, 265 (kg / cm ² ) to release the pressurized fluid and measure the safety of the circuit. Furthermore, each outbound route 2
3-1, 23-2, 23-3, and 23-4 are connected to the respective hydraulic motors 9 via the switching valve 21. The switching valve 21 and the hydraulic motor 9 are provided in parallel.
25-1, 25-2, 25-3, 25-4
Merge via the switching valve 21 and return to the hydraulic pump 17.

The operation of this embodiment will be described below.
First, the operation of the gear type flow divider 27 in the present embodiment will be described. The pressure generated by the hydraulic pump 17 is P, the flow rate of the pressure fluid to be sent out is Q, and the pressures of the pressure fluids sent to the four hydraulic motors are P ₁ , P ₂ , P ₃ ,
P ₄ and the flow rates are Q ₁ , Q ₂ , Q ₃ , and Q ₄ . If the fluid energy loss due to resistance such as viscous resistance in the hydraulic circuit is neglected, the fluid energy loss in the gear type flow divider 27 is extremely small, so that the work performed across the gear type flow divider 27 can be made constant. PQ = a _{P 1 Q 1 + P 2 Q} 2 + P 3 Q 3 + P 4 Q 4. The ratio of Q ₁ , Q ₂ , and Q ₃ is constant by the operation of the gear flow divider 27. Here, if Q ₁ , Q ₂ , Q ₃ , and Q ₄ are assumed to be equal, (Q / 4) = Q ₁ = Q ₂ = Q ₃ = Q ₄ . Therefore, the beginning of equation _{PQ = P 1 (Q / 4} ) + P 2 (Q / 4) + P 3 (Q / 4) + P 4 (Q / 4) next to a end _{4P = P 1 + P 2 +} P 3 + P 4 Become.

The upper limit of P becomes, for example, 200 (kg / cm ² ) by the function of the pressure reducing valve 19. P ₁ , P ₂ ,
The upper limits of P ₃ and P ₄ are set to, for example, 24
5 (kg / cm ² ).

If one of the hydraulic motors 9 fails,
The switching valve 21 of the hydraulic motor 9 is switched, and the pressure fluid is bypassed to the return path 25. Thus, the pressure fluid flows without using the hydraulic motor 9 (flow rate Q ₄ ),
And the pressure P ₄ is substantially zero. When P ₄ is 0, P ₁ , P ₂ , and P ₃ increase accordingly, as is apparent from the above equation. This means that the surplus power of the failed hydraulic motor is shifted to another hydraulic motor.

On the other hand, each hydraulic motor 9
In contrast, when the hydraulic circuit and the hydraulic pump 17 are independently provided in parallel, the normal excavating force can be obtained by 200 (kg / cm ² ) × 4 = 800 (kg / cm ² ). When one hydraulic motor 9 breaks down and its use is stopped, the excavating force is reduced to 200 (kg / cm ² ) × 3 = 600 (kg / cm ² ).

On the other hand, according to the present embodiment, as described above, for example, the pressure at which the pressure reducing valve 29 operates is set to 265 (or 2).
45 (kg / cm ² ), 265 (or 245 (kg / cm ² )
cm ² )) × 3 = 795 (or 735 (kg / cm ² )), and there is almost no decrease in the digging force.

In other words, since the remaining power of the failed hydraulic motor is shifted to another hydraulic motor, the torque of these other hydraulic motors is increased. In the above example, 200 (kg / cm) to 265 (or 245 (kg)
/ Cm ² )) in proportion to the increase in the value.

In the above-described embodiment, the case where one of the four hydraulic motors 9 has failed has been described. The lack of excavation power is covered by the motor.

In the above embodiment, four hydraulic motors 9 have been described. However, in other embodiments, two, three, or five or more hydraulic motors 9 may be provided.

[0020]

As described above, according to the hydraulic apparatus of the shielded excavator of the present invention, the excavating force which should have been insufficient for the failed hydraulic motor due to the characteristics of the gear type flow divider is reduced to other hydraulic motors. As a whole, the cutter obtains sufficient excavating power and can excavate. Therefore, even if some of the plurality of hydraulic motors fail, excavation can be continued without necessarily performing repair immediately, and work efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram according to an embodiment of the present invention.

FIG. 2 is a vertical sectional front view of the gear type flow divider of FIG. 1;

FIG. 3 is a vertical sectional side view of FIG. 2;

FIG. 4 is a horizontal sectional view of FIG. 2;

FIG. 5 is a longitudinal sectional view showing an example of a shield excavator.

FIG. 6 is a conventional hydraulic circuit diagram.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shield excavator 3 Shield body 5 Cutter disk 7 Ring gear 9 Hydraulic motor 11 Cutter chamber 13 Screw conveyor 15 Belt conveyor 19, 29 Pressure reducing valve 21 Switching valve 25 Drive gear 27 Gear type flow divider 27 Idle gear

Claims (1)

(57) [Claims] 1. A plurality of hydraulic motors, which mesh with a ring gear of a cutter disk provided in a shield excavator and rotate the cutter disk, and respective switches for bypassing a pressure fluid when each hydraulic motor fails. A hydraulic device for a shielded excavator, comprising: a valve; a gear-type flow divider for making a flow ratio of a pressure fluid sent to each hydraulic motor constant; and a hydraulic source for sending the pressure fluid through the gear-type flow divider.