JP2003286797A - Base pushing device, speed controller and speed control method of small-diameter pipe propulsion machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base pushing device, a speed controller and a speed control method of a small-diameter pipe propulsion machine for shortening a whole work time with a simple structure by increasing a pumping rate of a variable displacement hydraulic pump to a maximum limit to accelerate a jack while driving an electric motor without overload when the jack is returned, even when the electric motor of small capacity and low power consumption is used for driving the variable displacement hydraulic pump. <P>SOLUTION: When the jack returns (S10), the pumping capacity is adjusted and determined (S14) by a pumping capacity control means to be maximum within a range where the electric motor does not exceed a rated capacity on the basis of information on pumping pressure (S12) from a pressure detecting means. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an original pushing device, a speed control device and a speed control method for a small-diameter pipe propulsion device, and more particularly to a control technique for a former pushing hydraulic pump unit.

[0002]

[Related Background Art] As one of the construction methods for burying a small-diameter pipe in the ground, there is a pipe propulsion method in which a small-diameter pipe propulsion machine is used to excavate the natural ground and bury the pipe. The construction method is known from, for example, Japanese Patent Laid-Open No. 10-46986. A small-diameter pipe propulsion machine consists of a pre-conductor equipped with an excavation part at the tip and an extruding device, and a small-diameter pipe (fume pipe, steel pipe, etc.) is sequentially connected as a succeeding pipe behind the front conductor excavating the natural ground. , A device that pushes the subsequent pipe by pushing it with a former pushing device.

More specifically, a small-diameter pipe (fume pipe, steel pipe, etc.) has a length (for example, 1.5 to 2.5 m) that allows it to enter the space of the starting shaft, and the small-diameter pipe propulsion machine is With the jack of the pushing device, push the front conductor together with the small diameter pipe to propel the length of one small diameter pipe, and then return the jack, add one small diameter pipe as the succeeding pipe and push the succeeding pipe with the jack. Promote while repeating the work.
With this pipe propulsion method, it is possible to embed a small-diameter pipe up to about 50 to 250 m.

[0004]

By the way, the jack of the former pushing device of the small-diameter pipe propulsion device repeats forward and backward movements by the hydraulic pressure supply from the hydraulic pump, and the hydraulic pump is driven by the electric motor. The motor power is
Generally supplied from a commercial power source or generator. Therefore, it is necessary to reduce the power consumption of the electric motor as much as possible.

Further, small-diameter pipes are often arranged under the road, so that sufficient installation space cannot be secured for devices such as hydraulic pumps and electric motors, and it is also required to make each device as small as possible. . For this reason, as the normal hydraulic pump, a variable displacement type variable hydraulic pump that can obtain a large discharge pressure with low power consumption is adopted.

On the other hand, it is required to shorten the working time of the small-diameter pipe propulsion machine as much as possible. In this case, it is difficult to reduce the working time including the fact that the propulsion speed depends on the soil quality, etc. Since there is basically no load when returning, the work time can be shortened by increasing the discharge amount of the hydraulic pump when returning the jack to increase the returning speed of the jack.

However, when an electric motor of small capacity and small capacity with low power consumption is used, if the discharge amount of the hydraulic pump is increased to operate the hydraulic pump with the maximum capacity of the electric motor in order to increase the return speed of the jack, for example, There is a problem that the electric motor is overloaded due to a load such as pressure loss (the lower the hydraulic oil temperature, the greater) and is prone to burnout. Therefore, it is conceivable to provide a relief valve on the hydraulic circuit to release a pressure equal to or higher than a certain pressure so that the electric motor is not overloaded even if the discharge amount of the hydraulic pump is increased.

However, when the relief valve is provided to release the pressure in this way, there is a problem in that a sufficient flow rate of hydraulic oil is not supplied to the jack, and the return speed of the jack cannot be increased sufficiently. It is also conceivable to employ a constant power type pump (LV pump or the like) having a function of automatically reducing the discharge amount when the pressure rises while keeping the power constant.

However, when such a constant power type pump is used, it is desired to make the discharge flow rate of the hydraulic pump as constant as possible during propulsion to stabilize the propulsion speed, but the discharge flow rate fluctuates depending on the soil condition. However, there is a problem that the propulsion speed cannot be maintained constant. The present invention has been made based on the above circumstances, and an object of the present invention is to, even when a small-capacity electric motor with low power consumption is used for driving a variable hydraulic pump, when the jack is returned, A small-diameter tube propulsion machine that can increase the discharge amount of the variable hydraulic pump to the maximum speed of the jack while operating the electric motor without overloading, and can shorten the working time as a whole with a simple structure. An object is to provide an original pushing device, a speed control device, and a speed control method.

[0010]

In order to achieve the above object, in the original pushing device for a small-diameter pipe propulsion device according to claim 1, a jack is operated by hydraulic pressure, and a small-diameter pipe propulsion device is operated together with a subsequent small-diameter pipe. In a former pushing device of a small-diameter pipe propulsion device for propelling a small-diameter pipe, a variable-capacity variable hydraulic pump that supplies hydraulic pressure to the jack, an electric motor that drives the variable hydraulic pump, and the variable A discharge capacity control means for changing the discharge capacity of the hydraulic pump, and a pressure detection means for detecting the discharge pressure from the variable hydraulic pump are provided, and the discharge capacity control means detects the pressure when the jack returns and operates. Based on the discharge pressure information from the means, the discharge capacity is changed so that the electric motor becomes maximum within a range not exceeding the rated capacity.

Therefore, when the jack returns, it is preferable to increase the discharge capacity of the variable hydraulic pump to return the jack at a high speed as much as possible. On the other hand, in the variable hydraulic pump, the discharge pressure decreases as the discharge capacity increases. In this case, if the electric motor is operated at the rated capacity, the electric motor may be overloaded when the pressure loss in the hydraulic circuit that supplies the hydraulic pressure to the jack is large. As described above, based on the discharge pressure information from the pressure detecting means, the discharge capacity of the variable hydraulic pump is changed and set to the maximum value within the range in which the electric motor does not exceed the rated capacity. Prevent the overload condition, and prevent the electric motor from burning out, while maximizing the speed of the jack within the rated capacity of the electric motor. Is it possible to return actuation.

Further, in the speed control device for a small-diameter pipe propulsion device of claim 2, the jack is operated by hydraulic pressure to propel the small-diameter pipe propulsion device together with the succeeding small-diameter pipe to embed the small-diameter pipe. In a speed control device for a pipe propulsion device, based on discharge pressure information of a pressure detection unit that detects a discharge pressure from a variable hydraulic pump of a variable displacement type that supplies a hydraulic pressure to the jack when the jack returns and operates, It is characterized in that the discharge capacity of the variable hydraulic pump is controlled so that the electric motor for driving the variable hydraulic pump is maximized within a range not exceeding the rated capacity.

Therefore, when the jack is returned, it is preferable to increase the discharge capacity of the variable hydraulic pump to return the jack at a high speed as much as possible, while in the variable hydraulic pump, the discharge pressure is reduced when the discharge capacity is increased. In this case, if the electric motor is operated at the rated capacity, the electric motor may be overloaded when the pressure loss in the hydraulic circuit that supplies the hydraulic pressure to the jack is large. As described above, by controlling the discharge capacity of the variable hydraulic pump based on the discharge pressure information from the pressure detection means so that the electric motor is maximized within the range not exceeding the rated capacity, the electric motor exceeds the rated capacity. Keep the jack in the range of the rated capacity of the electric motor as quickly as possible while preventing the load condition and surely preventing the electric motor from burning. It is can be operated.

Further, in the speed control method for a small-diameter pipe propulsion device according to a third aspect of the present invention, the jack is operated by the hydraulic pressure discharged from the variable hydraulic pump of the variable displacement type driven by the electric motor, and the small-diameter pipe that follows is operated. In a speed control method of a small diameter pipe propulsion device for propelling a small diameter pipe propulsion device to bury a small diameter pipe, a first step of detecting a return operation of the jack and a discharge pressure from the variable hydraulic pump are detected. And a third step of controlling the discharge capacity so that when the jack is returned and operated, the electric motor is maximized within a range not exceeding the rated capacity based on the detected discharge pressure. It is characterized by including.

Therefore, when the jack is returned, it is preferable to increase the discharge capacity of the variable hydraulic pump to return the jack at a high speed as much as possible, while in the variable hydraulic pump, the discharge pressure is reduced when the discharge capacity is increased. In this case, if the electric motor is operated at the rated capacity, the electric motor may be overloaded when the pressure loss in the hydraulic circuit that supplies the hydraulic pressure to the jack is large. As described above, after the return operation of the jack is detected in the first step and the discharge pressure from the variable hydraulic pump is detected in the second step, the electric motor is rated based on the discharge pressure information in the third step. By changing and setting the discharge capacity of the variable hydraulic pump so that it becomes the maximum within the range that does not exceed the capacity, the electric motor will exceed the rated capacity and will be overloaded. So as not to, while reliably preventing the burnout of the electric motor, is it possible to maximally fast return actuation jack within the rated capacity of the electric motor.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram showing a usage state of a small-diameter pipe propulsion device to which a source pushing device of a small-diameter pipe propulsion device, a speed control device, and a speed control method of the present invention are applied. As shown in the figure, the small-diameter pipe propulsion device is roughly divided into a cylindrical leading conductor 1 and a former pushing device 2, and a cutter head 10 for excavating a natural ground is provided at the tip of the leading conductor 1. Is provided,
On the other hand, the former pushing device 2 includes a jack 4 which is operated by hydraulic pressure.
And a hydraulic unit 6 for controlling the hydraulic pressure of the hydraulic oil supplied to the jack 4. Although two jacks 4 are shown here, the number may be one.

When the small-diameter tube propulsion machine is used, the leading conductor 1 and the jack 4 are inserted into a starting shaft 7 which is dug vertically from the ground as shown in FIG. The jack 4 is installed so as to push the rear end of the front conductor 1 with the rod 5 while receiving a reaction force from the shaft wall while excavating the natural ground. FIG. 2 is a vertical cross-sectional view of the leading conductor 1.

As shown in FIG. 1, the cutter head 10 has a hydraulic motor 1 for rotating the cutter head 10.
2 is connected to the center portion of the front conductor 1 and a sediment pump tank 14 for temporarily pumping the excavated earth and sand 100 to the outside of the tunnel via the pressure pipe 18 and the earth and sand reservoir tank for temporarily accumulating the earth and sand 100. 16 are provided. Further, the front conductor 1 is provided with a direction correcting jack 19 for controlling the traveling direction of the front conductor 1, and the front conductor 1 is rotated around the outer periphery of the front conductor 1 by the reaction force of the hydraulic motor 12. A plurality of rib-shaped projections 20 are formed to prevent it.

FIG. 3 is a hydraulic circuit diagram of the hydraulic unit 6 for supplying hydraulic pressure to the jack 4. As shown in the figure, the jack 4 is a hydraulic cylinder, the pressure chamber 4a of the jack 4 is connected to the pipe line 30, and the pressure chamber 4b is connected to the pipe line 3.
2 is connected. As a result, the pipe 3
When the hydraulic oil is supplied through 0, the hydraulic oil in the pressure chamber 4b is discharged and the rod 5 advances, and when the hydraulic oil is supplied to the pressure chamber 4b through the conduit 32, the pressure chamber 4a operates. The oil is discharged and the rod 5 retracts.

The pipeline 30 and the pipeline 32 are connected to the high pressure pipeline 31 and the return pipeline 33 via an electromagnetic switching valve 34, and the switching valve 34 shuts off the flow of hydraulic oil. Position, communication between conduit 30 and high pressure conduit 31 and conduit 32
And the return conduit 33, the forward communication position for communicating with the conduit 33, the conduit 3
Communication between 0 and the return conduit 33, and conduit 32 and high pressure conduit 31
It is configured as a three-position switching valve having a reverse communication position for communicating with the.

A hydraulic pump unit 40 is provided in the high pressure pipeline 31, and the hydraulic pump unit 4
By discharging the hydraulic oil in the hydraulic oil tank 36 to the high-pressure pipeline 31 by 0, hydraulic pressure can be supplied to the jack 4.
The hydraulic pump unit 40 is configured such that the hydraulic pump 42 is driven by the electric motor 44.

The electric motor 44 generally has a small installation space in the work area because the work is performed on a road or the like.
Since a general commercial power source or a generator is used as a power source, a power source having a required minimum capacity with relatively small power consumption is used. Then, along with this, the hydraulic pump 42
As for the electric conductor 44 of the small capacity,
A variable hydraulic pump of variable displacement is used to generate a pressure capable of sufficiently propelling the engine. That is, the hydraulic pump 42 can easily change the discharge amount of the hydraulic oil, and if the discharge amount is controlled to increase, the discharge pressure can be reduced, but the flow rate of the hydraulic oil can be increased.
On the other hand, if the discharge amount is controlled so as to be reduced, the discharge pressure can be increased and the lead conductor 1 can be sufficiently propelled although the flow rate of the hydraulic oil is reduced. The hydraulic pump 42, together with the electric motor 44, is selected to have the minimum required specifications according to the maximum load during propulsion.

A pressure sensor (pressure detecting means) 38 for detecting the pressure in the high-pressure pipe 31, that is, the discharge pressure of the hydraulic pump 42 is interposed in the high-pressure pipe 31. further,
The high-pressure conduit 31 and the return conduit 33 are connected by a relief conduit 35, and hydraulic oil is allowed to escape into the relief conduit 35 so that the pressure in the high-pressure conduit 31 does not exceed a certain pressure. A relief valve 46 is installed.

The hydraulic unit 6 is provided with a controller 50, and the input side of the controller 50 is connected with the pressure sensor 38 and a changeover switch 52 for instructing the changeover of the changeover valve 34. . On the other hand, the output side of the controller 50 is connected to the hydraulic pump unit 40 together with the switching valve 34. Specifically, as shown in the block diagram of FIG. 4, the controller 50 includes a detection value acquisition unit 50a, a calculation unit 50b, and a command unit 50.
The pressure sensor 38 and the changeover switch 52 are connected to the detection value intake section 50a, and the hydraulic pump unit 40 is connected to the command section 50c.

Thus, when the changeover switch 52 is operated, the changeover valve 34 is changed over to either the forward communication position or the reverse communication position in accordance with the operation, and the jack 4 is operated.
The rod 5 can be moved forward or backward, and the discharge amount of the hydraulic pump 42 can be changed according to the switching of the switching valve 34. Further, the output of the electric motor 44 can be changed within the range of the rated capacity as required.

The operation of the small-diameter pipe propulsion device thus constructed and the control contents of the hydraulic pump unit 40 will be described below. First, the general operation and operation of the small diameter tube propulsion machine will be described. When the operator operates the changeover switch 52 to switch the changeover valve 34 to the forward communication position, hydraulic pressure is supplied to the pressure chamber 4a of the jack 4 to move the rod 5 forward, and while being pushed by the rod 5, the front conductor 1 is pressed. Will excavate the ground and proceed. When the rod 5 extends to the maximum length, the operator operates the changeover switch 52 to switch the changeover valve 34 to the reverse communication position. By doing so, the hydraulic pressure is supplied to the pressure chamber 4b of the jack 4, the rod 5 retracts, and the rod 5 returns to the original position.

When the rod 5 returns to the original position, the worker connects a small-diameter pipe (fume pipe, steel pipe, etc.) 60 behind the front conductor 1 as a succeeding pipe (refilling work). After that, when the changeover switch 52 is operated again to change over the changeover valve 34 to the forward communication position, as shown in FIG. 1, the rod 5 pushes the succeeding tube to propel the front conductor 1, and the front conductor 1 is pushed.
Goes further excavating the ground. Then, when the rod 5 extends to the maximum length again, the operator operates the changeover switch 52 to switch the changeover valve 34 to the reverse communication position. As a result, the rod 5 returns to the original position again, and in this state, the worker further adds the small diameter pipe 60 as a succeeding pipe. After that, the same operation is repeated, and the small-diameter pipe 60 is continuously buried in the ground without a gap.

The small-diameter pipe 60 has such a length that one of the small-diameter pipes 60 can sufficiently enter the space of the starting shaft (for example, 1.5 to
2.5 m), and the distance that the leading conductor 1 propels, that is, the distance in which the small-diameter pipe 60 can be embedded in the small-diameter pipe propulsion machine is, for example, 50 to 250 m. Next, the hydraulic pump unit 4
The control content of 0 will be described. FIG. 5 is a flowchart showing a control routine of pump control according to the present invention, which is executed by the controller 50. Hereinafter, description will be given along the flowchart.

In step S10, it is determined whether or not the jack 4 is in the propelling state (first step). That is,
Based on the information from the changeover switch 52, it is determined whether or not the changeover valve 34 is in the forward communication position in the detection value acquisition section 50a. The determination result of step S10 is false (N
In step o), when it is determined that the changeover valve 34 is in the reverse communication position and the jack 4 is currently in the returning state based on the information from the changeover switch 52, the process proceeds to step S12.

When returning the jack 4, it is preferable to return it as quickly as possible in preparation for the next propulsion operation. for that purpose,
It is preferable to set the discharge amount Q of the hydraulic pump 42 to the maximum.
However, as described above, when the rated capacity of the electric motor 44 is constant, if the discharge amount Q is controlled to increase, the discharge pressure P decreases. That is, when the load due to the resistance of the hydraulic oil flowing through the hydraulic circuit, that is, the pressure loss is large, when the discharge amount Q of the hydraulic pump 42 is set to the maximum, the discharge pressure P corresponds to the rated capacity of the electric motor 44. If the discharge pressure Pmax is exceeded, the electric motor 44 may be overloaded and burned. This tendency becomes more remarkable as the temperature of the hydraulic oil becomes lower and the viscosity becomes higher, as in winter work.

Therefore, in the present invention, after step S12, such burnout of the electric motor 44 is prevented. In step S12, the discharge pressure information P from the pressure sensor 38 is detected by the detection value capturing section 50a.
Is read (second step). In step S14, based on the discharge pressure information P, the calculation unit 50b
The discharge amount Q is set so that the discharge pressure P is equal to or lower than the maximum discharge pressure Pmax (P ≦ Pmax). That is, FIG. 6 shows the relationship between the discharge amount Q and the discharge pressure P in the variable displacement hydraulic pump 42, that is, the relationship between the discharge amount Q and the maximum discharge pressure Pmax when the rated capacity of the electric motor 44 is constant. Although the (power curve) is shown as a map, when returning the jack 4, the discharge amount Q is set based on the map so that the discharge pressure P does not exceed the power curve (discharge volume control). Means, third step).

The discharge amount Q is expressed by the following equation showing the power curve.
It can also be calculated from (1). Discharge amount Q = (rated capacity of electric motor) × coefficient K × efficiency μ / discharge pressure P (1) Here, the coefficient K is a conversion coefficient obtained based on an experiment, and the efficiency μ is mainly unique to each hydraulic pump. Pump efficiency. Then, in step S18, the hydraulic pump 4
The command value of the discharge amount Q is output to 2.

Specifically, for example, in FIG.
When A is assumed to be the maximum discharge amount, the maximum discharge pressure Pmax based on the power curve is the value at the point A, but the detected value of the discharge pressure P exceeds the power curve due to the load such as pressure loss and becomes the value at the point A '. In such a case, the discharge amount Q is equal to the detection value of the discharge pressure P, and the value Q corresponding to the point B on the power curve.
Change to B.

As a result, the electric motor 44 is prevented from exceeding the rated capacity and being overloaded, and the electric motor 44 is prevented.
It is possible to return the jack 4 as quickly as possible within the range of the rated capacity of the electric motor 44 while reliably preventing the burning of the jack. In particular, when there is almost no pressure loss in the hydraulic circuit and the detection value of the discharge pressure P does not exceed the power curve even if the discharge amount Q is set to the maximum discharge amount QA, the discharge amount Q is set to the maximum discharge amount. As a quantity QA, the jack 4 can be returned at extremely high speed.

That is, even when the electric motor 44 having a small capacity is used, the electric motor 44 is surely protected and the construction is simple and the operation time for burying the small diameter pipe 60 by the small diameter pipe propulsion machine is reduced. It can be shortened as a whole and work efficiency can be improved. On the other hand, if the determination result of step S10 is true (Yes) and it is determined that the jack 4 is currently in the propelling state, step S16
Proceed to.

When the jack 4 is propelled, the propelling speed should be as constant as possible, and in order to keep the propelling speed constant, the discharge amount Q should be kept constant. Therefore, in step S16, as shown in FIG.
The discharge rate Q of the hydraulic pump 42 is set to a predetermined value Q0 corresponding to the propulsion speed (Q = Q0) so that the propulsion speed is constant (for example, set in the range of 0 to 20 cm / min).

Then, similarly to the above, in step S18, the command value of the discharge amount Q is output to the hydraulic pump 42.
Thereby, the lead conductor 1 can be propelled while keeping the propelling speed constant. That is, the work of burying the small-diameter pipe 60 can be carried out in a stable manner. As shown in FIG. 6, in the vicinity of the predetermined value Q0, the original power curve is shown by a broken line, while the relief valve 46 is actually used.
As a result, the maximum discharge pressure Pmax becomes P0 as shown by the solid line.
Is restricted to. This is because the discharge amount Q is fixed to a predetermined value Q0 in order to keep the propulsion speed constant during the propulsion.
This is to prevent the discharge pressure P from inadvertently exceeding the power curve when the resistance rises due to changes in the soil properties to be excavated. As a result, even during propulsion, the electric motor 44 is not overloaded and the occurrence of burnout is reliably prevented.

Here, the set value P0 of the relief valve 46 is set.
Is set so that the discharge pressure P can be propelled at a predetermined speed (for example, a maximum value of 20 cm / min in the above range) without exceeding the set value P0 in the assumed soil. Although the description is completed above, the present invention is not limited to the above embodiment. For example, in the above-described embodiment, the case where the jack 4 is returned for the refilling work has been described.
Are repeatedly returned and collected, and the present invention can be applied as it is during the collection operation of the pressure-feeding pipe 18 and the like. That is, when the pressure feed pipe 18 or the like is collected, sliding resistance works, but in this case as well, the discharge amount Q is set so that the discharge pressure P does not exceed the power curve, and the electric motor 44 is set. Can be recovered as quickly as possible within the range of the rated capacity of the electric motor 44, while preventing the vehicle from exceeding the rated capacity and becoming overloaded.

[0039]

As described above, according to the first aspect of the present invention.
According to the former pushing device of the small-diameter pipe propulsion device, when the jack is returned, the variable hydraulic pump is designed so that the electric motor is maximized within the range not exceeding the rated capacity based on the discharge pressure information from the pressure detection means. Since the discharge volume of is changed and set,
It is possible to prevent the electric motor from exceeding the rated capacity and become overloaded, and reliably prevent the electric motor from being burnt out, and to quickly return the jack to the maximum speed within the rated capacity of the electric motor.

Therefore, even when an electric motor having a small capacity is used, the electric motor is surely protected,
It is possible to shorten the working time for burying a small-diameter pipe by the small-diameter pipe propulsion device as a whole, and improve the work efficiency. Further, according to the speed control device for a small diameter pipe propulsion device of claim 2, when the jack is returned and operated, the electric motor becomes maximum within a range not exceeding the rated capacity based on the discharge pressure information from the pressure detecting means. The discharge capacity of the variable hydraulic pump is controlled so that the electric motor does not exceed the rated capacity and becomes overloaded, and the electric motor is reliably prevented from burning, while the jack is operated within the rated capacity of the electric motor. Can be activated as quickly as possible.

Therefore, even when an electric motor having a small capacity is used, the electric motor is surely protected,
It is possible to shorten the working time for burying a small-diameter pipe by the small-diameter pipe propulsion device as a whole, and improve the work efficiency. According to the speed control method for a small diameter pipe propulsion device of claim 3, when the jack is returned, the return operation of the jack is detected in the first step, and the discharge from the variable hydraulic pump is performed in the second step. After detecting the pressure, in the third step, the discharge capacity of the variable hydraulic pump is controlled based on the discharge pressure information so that the discharge capacity of the variable hydraulic pump is maximized within a range not exceeding the rated capacity. It is possible to prevent the overload state from being exceeded and to reliably prevent the electric motor from being burnt out, and to return the jack to the maximum speed as fast as possible within the rated capacity of the electric motor.

Therefore, even when an electric motor having a small capacity is used, the electric motor is surely protected,
It is possible to shorten the working time for burying a small-diameter pipe by the small-diameter pipe propulsion device as a whole, and improve the work efficiency.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a usage state of a small-diameter pipe propulsion device to which an original pushing device, a speed control device, and a speed control method for a small-diameter pipe propulsion device of the present invention are applied.

FIG. 2 is a vertical sectional view of a leading conductor.

FIG. 3 is a hydraulic circuit diagram of a hydraulic unit that supplies hydraulic pressure to a jack.

FIG. 4 is a block diagram showing a connection relationship of controllers.

FIG. 5 is a flowchart showing a control routine of pump control according to the present invention.

FIG. 6 shows a discharge amount Q and a maximum discharge pressure Pma when the rated displacement of the electric motor is constant in a variable displacement hydraulic pump.
It is a map which shows the relationship (power curve) with x.

[Explanation of symbols]

1 Leader 2 original pushing device 4 jacks 6 hydraulic unit 10 cutter head 34 Switching valve 38 Pressure sensor (pressure detection means) 40 hydraulic pump unit 42 Hydraulic pump (variable hydraulic pump) 44 electric motor 50 controller 50a Detection value acquisition unit 50b operation unit 50c command unit 52 Changeover switch 60 Small diameter pipe (fume pipe, steel pipe, etc.)

Claims (3)

[Claims] 1. An original pushing device for a small-diameter pipe propelling machine, in which a jack is operated by hydraulic pressure and a small-diameter pipe propelling machine is propelled together with a subsequent small-diameter pipe to bury the small-diameter pipe. Variable hydraulic pump of variable displacement type, electric motor for driving the variable hydraulic pump, discharge capacity control means for changing the discharge capacity of the variable hydraulic pump, and pressure detection for detecting the discharge pressure from the variable hydraulic pump The discharge capacity control means, when the jack is returned and actuated, based on discharge pressure information from the pressure detection means, sets the discharge capacity so that the electric motor becomes maximum within a range not exceeding the rated capacity. A former pusher for small-diameter pipe propulsion machines, which is characterized by being changed. 2. A speed control device for a small diameter pipe propelling machine, wherein a jack is operated by hydraulic pressure and a small diameter pipe propulsion device is propelled together with a small diameter pipe that follows to embed the small diameter pipe. When the electric motor driving the variable hydraulic pump does not exceed the rated capacity on the basis of the discharge pressure information of the pressure detection unit that detects the discharge pressure from the variable displacement variable hydraulic pump that supplies the hydraulic pressure to the jack. The speed control device for a small-diameter pipe propulsion device, wherein the discharge capacity of the variable hydraulic pump is controlled so as to be maximum. 3. A small-diameter pipe is buried by operating a jack by hydraulic pressure discharged from a variable-capacity variable hydraulic pump driven by an electric motor to propel a small-diameter pipe propelling machine together with a small-diameter pipe that follows. In a speed control method for a small diameter pipe propulsion device, a first step of detecting a return operation of the jack, a second step of detecting a discharge pressure from the variable hydraulic pump, and a return operation of the jack: A third step of controlling the discharge capacity so that the electric motor has a maximum value in a range not exceeding the rated capacity based on the detected discharge pressure; and a speed of the small diameter tube propulsion machine. Control method.