JP2757699B2 - Hydraulic system for multiple cutter excavator - 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 driving a plurality of cutters such as an excavator used in civil engineering work, for example, a hydrophrase excavator and a shield excavator.

[0002]

2. Description of the Related Art There are various types of excavators used for civil engineering and the like. For example, there is a hydrophrase excavator that is a type of excavator that excavates a deep flute to construct an underground wall, or a shield excavator that excavates a side hole or a tunnel. In these excavators, a cutter that actually excavates with a face is rotationally driven by a hydraulic motor.

An example of such an excavator is shown in a shield excavator in FIG. The cylindrical shield body 1 forming the outer frame of the excavator 9 moves forward with respect to the ring-shaped segment provided inside the already excavated tunnel by controlling the hydraulic pressure of the shield jack. . A substantially disk-shaped cutter disk 3 is provided on a front surface of the frame 1, and a ring gear 5 fixed to the cutter disk 3 is provided.
The excavation is performed by the hydraulic motor 7 that meshes with the shaft. The excavated earth and sand is taken out from the inside of the cutter chamber 9 by the screw conveyor 11 and further sent backward by the conveyor belt 13. A plurality of cutters 3 for performing such excavation may be provided, and the plurality of cutters are driven by hydraulic motors 7 provided respectively.

FIG. 6 shows a hydraulic circuit for sending a pressure fluid to each hydraulic motor 7. That is, the hydraulic unit 15 as the hydraulic source
, Two independent hydraulic circuits 17 are provided in parallel,
The pressure fluid is sent to different hydraulic motors 7. Each hydraulic circuit 17 is provided with a pressure reducing valve 19, for example, 200
(Kg / cm ² ) to keep the circuit 17 safe. The flow rate of the pressure fluid in each circuit 17 is, for example, 180
(L / min) and is sent to each hydraulic motor 7 via the switching valve 21.

[0005]

However, since the hydraulic circuits 17 are provided independently in parallel and provided separately for each hydraulic motor 7, the amount of hose for forming the hydraulic circuit 17 is correspondingly large. Not only that, if one of the cutters receives a large resistance against, for example, a rock or the like, the cutter stops and the other cutter idles.

The present invention has been made in order to solve the above-mentioned drawbacks, and the amount of hoses forming a hydraulic circuit can be reduced, and even if one of the cutters receives a large resistance, the other cutters idle. An object of the present invention is to provide a hydraulic device of a multi-cutter excavator that can perform excavation without overcoming resistance.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above objects, the present invention provides a plurality of cutters provided in an excavator, a hydraulic motor for driving each cutter, and a pressure supplied to each hydraulic motor. It comprises a gear type flow divider for making the flow ratio of the fluid constant, and a hydraulic source for sending a pressurized fluid through the gear type flow divider.

[0008]

There is no need to provide a hydraulic circuit in parallel between the hydraulic source and the gear type flow divider. In addition, if a large resistance is applied by rocks or the like hitting one of the cutters, the load on the cutter increases. In this case, due to the operation of the gear-type flow divider, the remaining capacity of the other cutters with a small load is reduced by this load. Is shifted to a larger cutter. Therefore, the excavating force can be concentrated on the cutter having a large load.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One example of the present invention will be described below with reference to FIGS. The excavator of this embodiment is a hydrophrase excavator, which has cutters on the left and right sides, and each cutter is driven by a separate hydraulic motor 7.

FIG. 1 is a circuit diagram for sending a pressure fluid from a hydraulic source to the hydraulic motor 7.

A forward path 23 and a return path 25 of a circuit connected to the hydraulic unit 15 serving as a hydraulic source are connected by a pressure reducing valve 19. This pressure reducing valve 19 is, for example, 200 (kg /
Open with a pressure of cm ² ) to keep the whole hydraulic circuit safe. The outward path 23 coming out of the hydraulic unit 15 is, for example, 360 (ml
/ Min), and then branches off at the geared flow divider 27. Therefore, the gear type flow divider 2
7 and the hydraulic unit 15 are connected only by the forward path 23 and the return path 25, and the number of pipes forming a circuit is small.

The gear type flow divider 27 is shown in FIGS. As shown in the figure, a drive gear 29 and an idle gear 31 are provided in mesh with each other on the outward path after branching. The drive gear 29 has two outgoing paths 23A, 2 after branching.
3B, the idle gear 31 is separate and idles in each forward path. Therefore, each gear 29, 31
Are the same, and the number of rotations is proportional to each flow rate of the pressure fluid. Therefore, two outgoing routes 23A and 23B after branching
Is always constant.

The outgoing path 23 exiting the gear type flow divider 27
A and 23B are respectively connected to the hydraulic motor 7 via the switching valve 21.
Connect to After returning from the hydraulic motor 7, the return path 25 returns to the hydraulic unit 15. A bypass is provided in the two forward paths 23A and 23B on the upstream side of the switching valve 21 and is connected to a pressure reducing valve 35 via a check valve 33. This pressure reducing valve 35 is
For example, the hydraulic circuit 17 is opened at a pressure of 245 (g / cm ² ) to release the pressure fluid to the return path 25 and maintain the safety of the hydraulic circuit 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 unit 15 is P, the flow rate of the pressure fluid to be sent is Q, the pressure of the pressure fluid sent to one hydraulic motor is P ₁ , the flow rate is Q _2, and the pressure to the other is P _{2, the} flow rate is Q _2, and ignoring the fluid energy loss due various resistance in the hydraulic circuit, the fluid energy loss in the gear type flow divider 27 is very small, PQ = P ₁ because it is the work to be performed is constant Q ₁ + P a ₂ Q _2. By the operation of the gear type flow divider 27, the ratio between Q ₁ and Q ₂ is constant. Here, if Q ₁ and Q ₂ are equal, (Q / 2) = Q ₁ = Q ₂ . Therefore, the first equation is PQ = P ₁ (Q / 2) + P ₂ (Q / 2), and eventually 2Q = P ₁ + P ₂ . The upper limit of P is set by the pressure reducing valve 19 (200 (kg / cm ² )) and is substantially constant.

If one of the cutters hits an obstacle such as a rock and receives a large resistance, the cutter becomes difficult to rotate, and the other cutter starts to idle.
With this idling, the other P ₁ becomes very small, while the other P ₂ becomes very large. Therefore, the remaining power of the cutter trying to run idle is shifted to the cutter receiving a large resistance.

The above points will be specifically illustrated by numerical values.
That is, when the pressure P ₂ loads one cutter becomes larger 245 (kg / cm ²⁾ next to the upper limit, the load is small the pressure P ₁ of the other cutter becomes 100 (kg / cm ²⁾ is Conventionally, as shown in FIG. 6, the pressure reducing valve 21 operates for one of the cutters, and the hydraulic motor 7 for one of the cutters is stopped. Other cutters are driven normally, but are effectively idle because the entire excavator does not advance. When, according to the present embodiment which 2P = P ₁ from the equation of P ₁ + P ₂ becomes substantially 0 by general idle state, reserve capacity resulting therefrom (pressure P ₁ = 100 (kg / c
m ² )) and another hydraulic motor 7 (pressure P ₂ = 245 (kg / c
m ² )) and the pressure P ₂ = 345 (kg
/ Cm ² ) withstands the load and the cutter can rotate. Excavation is continued by this rotation, and the excavator moves forward. Therefore,
The cutter, which was about to spin, could contact the new ground and continue digging. It should be noted that even when one cutter is rotating under a large load of the pressure P ₂ = 345 (kg / cm ² ), the hydraulic unit 1
The pressure P generated by 5 can be small. That is, when P ₂ in 2P = 0 + P ₂ is 345 (kg / cm ^2), P 17
Since only 2.5 (kg / cm ² ) is less than 200 (kg / cm ² ), both hydraulic motors 7 are operated without operating the pressure reducing valve 19.
Can continue to work.

As described above, according to this embodiment, a large load is generated because one of the cutters hits a rock or the like.
Even ₂ increases, P ₁ becomes sufficiently small in place, without so large conventional pressure P itself to hydraulic unit 15 generates, it is possible to continue drilling to rotate the cutter. In this way, the operation of the gear-type flow divider 27 shifts, as it were, the surplus power of the cutter with a small load to the cutter with a large load, so that the excavation can be continued by concentrating a large excavation force at one place.

Although the excavator has been described as a hydrophrase excavator in the above embodiment, other excavators such as a shield excavator may be used in other embodiments. The present invention can be implemented in the case of a hydraulic device that includes a plurality of cutters and is driven by different hydraulic motors, even for other excavators.

[0019]

As described above, according to the hydraulic device for a multi-cutter excavator of the present invention, the hydraulic circuit between the hydraulic source and the gear type flow divider does not need to be provided in parallel, The amount of hose for forming the circuit is reduced. Therefore, the amount of the whole hose can be reduced.

When a large resistance is generated in one cutter and the load is increased, the surplus power of the other cutter with a small load is shifted to the cutter with a large load by the action of the gear type flow divider. The large cutters can be concentrated, and the stopping and idling of the cutters of the entire multi-cutter excavator can be suppressed.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit showing one embodiment of the present invention.

FIG. 2 is a longitudinal sectional 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 schematic longitudinal sectional view showing an example of a conventional excavator.

FIG. 6 is a hydraulic circuit diagram for driving the cutter of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shield body 3 Cutter disk 7 Hydraulic motor 9 Cutter chamber 11 Screw conveyor 13 Belt conveyor 15 Hydraulic unit 19 Pressure reducing valve 21 Switching valve 27 Gear type flow divider 29 Drive gear 31 Idle gear 33 Check valve 35 Pressure reducing valve

Claims (1)

(57) [Claims] 1. A plurality of cutters provided on an excavator,
A plurality of cutters each comprising: a hydraulic motor that drives each cutter, a gear-type flow divider that keeps a flow ratio of the pressure fluid sent to each hydraulic motor constant, and a hydraulic source that sends the pressure fluid through the gear-type flow divider. Excavator hydraulic system.