JP2813285B2 - Sediment pumping equipment for small diameter pipe propulsion machines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sediment pumping apparatus for discharging and excavating excavated earth and sand from a small-diameter pipe propulsion machine to the ground.

[0002]

2. Description of the Related Art A typical example of a sediment pumping apparatus for a small-diameter pipe propulsion machine is disclosed in Japanese Patent Application Laid-Open No. Sho 59-51171. This sediment pumping device is composed of a sediment pressing pump installed in a small-diameter pipe propulsion machine and a hydraulic operating unit installed on the ground.

[0003] As shown in FIGS. 6 and 7, a sediment pressure pump 100 includes a cylindrical casing 13, an outer cylinder 18 that slides inside the casing 13, and an outer cylinder 1.
8 outer cylinder pushing piston 1 connected to the rear end
9, an inner cylinder 29 that slides in the outer cylinder 18,
Sediment feeding piston 30 connected to the front end of inner cylinder 29, inner cylinder pushing piston 31 connected to the rear end of inner cylinder 29, outer cylinder pushing piston 1
9, a first oil chamber 20 formed between the rear end surface of the casing 13 and the rear wall of the casing 13, the outer peripheral surface of the outer cylinder 18 and the casing 1
A second oil chamber 21 formed between the inner peripheral surface of the piston 3 and a third oil chamber 32 formed between a rear end surface of the inner cylinder pushing piston 31 and a front end surface of the outer cylinder pushing piston 19. ,
A fourth oil chamber 33 formed between the outer peripheral surface of the inner cylinder 29 and the inner peripheral surface of the outer cylinder 18, the first port 14 of the casing 13 communicating with the first oil chamber 20, and the casing communicating with the second oil chamber 21. 13, second oil passages 22 and 23 communicating between the first oil chamber 20 and the third oil chamber 32, and oil paths 26 and 27 communicating between the second oil chamber 21 and the fourth oil chamber 33. , 2
9 ', 34 and a spool valve 24 for opening and closing the oil passages 22, 23.

[0006] In FIGS. 6 and 7, reference numeral 1 denotes a sediment storage tank, 2 denotes an opening of the sediment storage tank 1 to which the sediment 36 is supplied, 3 denotes a sediment suction port in the sediment storage tank 1,
4 and 5 are the side walls of the sediment storage tank 1 and 6 is the outer cylinder 1
8 and an oil tank for lubricating each sliding surface of the earth and sand pressure feeding piston 30, 7 is a rear wall of the oil tank 6, 8 is a earth and sand pressure feeding pipe, 9 is a flange for connecting the earth and sand pressure feeding pipe 8, 10 is a seal casing, 11 is a seal, 12 is a seal stop ring, 16 is a mounting member between the casing 13 and the oil tank rear wall 7, 17 is a support member of the outer cylinder 18, and 25 is an oil passage 2.
Reference numeral 28 denotes a throttle provided on the piston 2, reference numeral 28 denotes a stopper for the outer cylinder pushing piston 19, and reference numeral 35 denotes a stopper for the inner cylinder pushing piston 31.

FIG. 2 is a hydraulic circuit diagram of a conventional example for operating the sediment pump 100. The upper part of the line AA in FIG. 2 is the sediment pump 100 installed in the small-diameter pipe propulsion device.
And below the line B-B is a hydraulic operating unit 2 installed on the ground.
00 is shown.

The hydraulic operating section 200 includes an oil tank 37, an electric motor 38, a hydraulic pump 39, and a relief valve 4 connected between a discharge-side oil passage 40 and a return-side oil passage 41 of the hydraulic pump 39.
2 and a directional control valve 43.

[0007] 44,4 between line AA and line BB in FIG.
5 is a first port 14 and a second port 15 provided in a casing 13 of the earth and sand pressure pump 100 and a hydraulic operating unit 20.
5 shows an oil passage connecting between the directional control valve 43 of FIG. These oil passages 44 and 45 are connected and extended sequentially with the propulsion of the small-diameter pipe propulsion machine. Usually, hydraulic hoses with joints at both ends having the same length as the buried pipe are used.

FIG. 8 shows the operation sequence of the earth and sand pressure pump 100. In the forward process of the earth and sand pressure pump 100, the solenoid 43a of the direction switching valve 43 is energized, and the direction switching valve 43 is turned on.
Is switched to a position connecting the oil passage 40 and the oil passage 44, and the oil passage 41 and the oil passage 45. When the pressurized oil is supplied to the first oil chamber 20 via the oil passage 44 and the first port 14, the outer cylinder pushing piston 19 is pushed forward from the state shown in FIG. Prior to 30, outer cylinder 18 is advanced. The outer cylinder 18 moves forward while taking in the sediment near the sediment suction port 3 of the sediment storage tank 1,
At the same time as the outer cylinder pushing piston 19 comes into contact with the stopper 28, the tip portion 18 'of the outer cylinder 18 comes into close contact with the seal 11, and as shown in FIG. Isolate from tank 1. in the meantime,
The oil in the second oil chamber 21 is returned to the oil tank 37 through the second port 15 and the oil passage 45.

When the outer cylinder pushing piston 19 comes into contact with the stopper 28, the spool valve 24 mounted on the piston 19 is pushed backward by the stopper 28, and the oil passages 22 and 23 are communicated. Thereafter, as shown in FIG. 8C, the inner cylinder pushing piston 31 is pushed forward by the pressure oil flowing from the first oil chamber 20 to the second oil chamber 21 through the oil passages 22 and 23. Then, the earth and sand pressure feeding piston 30 moves forward together with the inner cylinder 29, and pushes out the earth and sand 36 taken in the outer cylinder 18 to the earth and sand pressure feeding pipe 8 and feeds it. Meanwhile, the oil in the fourth oil chamber 33 is
4, 29 ', 27, 26, second oil chamber 21, second port 1
5. The oil is returned to the oil tank 37 through the oil passage 45.

[0010] The oil chambers 20, 3 generated at the end of the advance process in which the inner cylinder pushing piston 31 abuts the stopper 35.
When the pressure rise in the oil passage 2 and the oil passage 44 is detected by a pressure detector (not shown), the solenoid 43b of the direction switching valve 43 is energized by the signal in place of the solenoid 43a.
The direction switching valve 43 is switched to a position where the oil passage 40 and the oil passage 45 and the oil passage 41 and the oil passage 44 are connected. Thereby, the earth and sand pump 100 moves to a retreating process. In the retreat process,
Pressure oil is supplied to the second oil chamber 21 via the oil passage 45 and the second port 15, and the spool oil 24 moves further rearward by the oil pressure, closing the oil passages 22 and 23 and pushing the outer cylinder. The piston 19 is pushed rearward, causing the outer cylinder 18 to retract. Meanwhile, the oil in the first oil chamber 20 is returned to the oil tank 37 through the first port 14 and the oil passage 44.

When the outer cylinder pushing piston 19 hits the rear wall of the casing 13 and stops, the spool valve 24 also hits the rear wall of the casing 13 and is pushed forward, so that the oil passages 22 and 23 communicate. Then, the second oil chamber 2
1 through the oil passages 26, 27, 29 ', 34 to the fourth oil chamber 3
Piston 3 for pushing the inner cylinder by the pressure oil flowing into
1 is pushed rearward, and the earth and sand pressure feeding piston 30 moves backward together with the inner cylinder 29. Meanwhile, the oil in the third oil chamber 32 is supplied to the oil passages 28 and 22, the first oil chamber 20, the first port 14,
The oil is returned to the oil tank 37 through the oil passage 44.

The oil chamber generated at the end of the retreating process in which the outer cylinder pushing piston 19 contacts the rear wall of the casing 13 and the inner cylinder pushing piston 31 also contacts the front end face of the outer cylinder pushing piston 19. When the pressure rise in the oil passage 45 is detected by a pressure sensor (not shown), the solenoid 43b of the direction switching valve 43
Instead, the solenoid 43a is energized, and the earth and sand pressure pump 100 moves to the forward step again. At this time, the first oil chamber 2
The spool valve 24 is further pushed forward by the pressure oil supplied to the cylinder 0, and the oil passages 22 and 23 are closed as shown in FIG. By repeating the above-described operation cycle, the earth and sand pump 100 intermittently pumps the earth and sand.

[0013]

FIG. 9 shows an entire cross section of a small-diameter pipe thruster 300 equipped with the above-mentioned earth and sand pressure pump. The small-diameter pipe propulsion device 300 excavates the ground G with a rotary excavation portion 302 provided at the tip of a propulsion device main body 301, and excavates with a viscosity imparting liquid such as a bentonite solution injected from an injection port 303 of the rotary excavation portion. The earth and sand is stirred and mixed to form a mud having plastic fluidity, and the muddy excavated earth and sand is pumped through the earth and sand passage 304 between the propulsion unit main body 301 and the ground to be installed in the propulsion unit main body 301.
The sediment storage tank 1 is taken into the tank 1, and the soil is pressed and discharged through the sediment feeding pipe 8 by the above-described sequential operation of the outer cylinder 18 and the sediment feeding piston 30, and is followed by the propulsion unit main body 301 by the main pushing device installed in the starting shaft. Buried pipe 3
05, and pipes are buried in the ground one by one (see Japanese Patent Application Laid-Open No. 1-263386).

In a small-diameter pipe propulsion device having a structure shown in FIG. 9 in which a portion of muddy excavated earth and sand is propelled while being filled between the outer circumference of the buried pipe and the ground, the mud on the outer circumference of the buried pipe is used as lubricating material. It has a role, and it has been demonstrated in actual construction that the required thrust is significantly reduced compared to small-diameter pipe propulsion machines of other construction methods. The propulsion distance of the small-diameter pipe thruster is limited by the compressive strength or buckling strength of the buried pipe.
m. On the other hand, the small-diameter pipe propulsion device having the structure shown in FIG. 9 is capable of prolonging the propulsion distance by a considerable decrease in the required thrust, and has a propulsion performance of 200 m or more per span.

A long propulsion distance has great constructional advantages, such as a reduction in the number of starting shafts, and therefore a longer distance is desired.

Although it has been confirmed by experience that the small-diameter pipe propulsion device having the structure shown in FIG. 9 has no problem in terms of thrust even when the propulsion distance is 200 m or more, it will be attempted to increase the propulsion distance to about 300 m in the future. In such a case, it was found that the propulsion distance was limited by the pressure loss of the oil passage connecting the earth and sand pump and the hydraulic operating unit on the ground. The situation will be described below.

In this type of small-diameter pipe propulsion machine having an excavation outer diameter of about 350 to 800 mm, it is impossible to install the entire earth and sand pumping device including the hydraulic operation unit in the space, and as shown in FIG. Only the earth and sand pressure pump 100 is installed in the machine, and a hydraulic operating unit 200 including a hydraulic source and a directional control valve is provided.
Is installed on the ground, and an oil passage 4 such as a hydraulic hose that passes between the earth and sand pump 100 and the hydraulic operation unit 200 through a buried pipe.
There is no other way but to connect at 4,45. In this case, as the propulsion distance increases, the oil passages 44,
45 is also longer.

In such a small-diameter pipe propulsion device, the cross-sectional area of the first oil chamber 20 is smaller than the pressure receiving area of the outer cylinder pushing piston 19 during the forward movement of the earth and pressure pump 100 shown in FIG. (This area is referred to as A1). In the retreating step, the cross-sectional area of the second oil chamber 21 becomes the pressure receiving area of the outer cylinder pushing piston 19 (this area is A2). There is an area difference of about A1 / A2 ≒ 3 between the pressure receiving area A1 in the forward step and the pressure receiving area A2 in the reverse step due to structural factors. Therefore, assuming that the amount of oil supplied to the first port 14 through the oil passage 44 during the forward process is Qcm ³ / min, the second port 1
The amount of oil discharged from 5 through the oil passage 45 to the oil tank 37 is about Q / 3 cm ³ / min. Further, the amount of oil supplied to the second port 15 through the oil passage 45 during the retreating process is represented by Qc
m ³ / min, the amount of oil discharged from the first port 14 through the oil passage 44 to the oil tank 37 is about 3 Qc
m ³ / min.

In the sediment pump 100 shown in FIG. 6, substantially only work (sediment pumping) is performed during the forward step, and during the retreat step, the moving parts (the outer cylinder 18, the sediment pumping piston 30, etc.) are pulled back. Only. Nevertheless, the thickness of the hydraulic hose and the capacity of the directional control valve 43 used in the oil passage 44 of the earth and sand pumping device are determined by the return oil amount ³ Qcm ³ / min during the retreating step which is not involved in the work, which is a considerable waste in equipment. was there.

Further, if the thickness of the hydraulic hose of the oil passage 44, which can be easily connected manually, is set to 1 inch and the amount of oil supplied to the sediment pressure pump 100 is set to 70 × 10 ³ cm ³ / min, the retreating process is performed. Sometimes the amount of oil returned through oil line 44 is about 21
0 × 10 ³ cm ³ / min, and the flow velocity in the oil passage 44 is about 6.9 m / sec. Therefore, when the oil passage 44 is extended to 300 m, the pressure loss of the hydraulic hose excluding the joint portion alone is 100 kgf / min. cm ² or so, the inclusion of pressure loss of the joint portion, the pressure loss of the entire oil passage 44 is 200 kgf / cm ²
That is all. The circuit set pressure of the hydraulic circuit shown in FIG.
kgf / cm ² , the oil passage 44 during the retreating process
It can be seen that when the pressure loss becomes 200 kgf / cm ² or more, normal operation of the earth and sand pressure pump becomes impossible, and the propulsion distance is limited by the pressure loss of the oil passage 44.

In order to extend the propulsion distance, it is conceivable to increase the circuit set pressure beyond the pressure loss. However, all the pressure loss in the oil passage 44 during the retreating process becomes heat and the oil temperature rises. The increase in the loss is not preferable from the viewpoint of the hydraulic circuit and the power loss.

The present invention has been made in view of the above points, and operates a sediment pressure pump mounted on a small-diameter pipe propulsion machine with a smaller amount of oil supplied from a hydraulic operating unit in the same manner as a conventional one, and retreats the same. By reducing the amount of oil returned to the hydraulic operation unit during the process, the pressure loss of the oil passage connecting the earth and sand pump and the hydraulic operation unit on the ground is reduced, the propulsion distance is extended, and the earth and sand pumping device It is an object of the present invention to eliminate waste on the equipment side and economically configure the apparatus.

[0023]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a small-diameter pipe propulsion device in which a cylindrical casing, an outer cylinder sliding in the casing, and a rear end of the outer cylinder are connected. Outer cylinder pushing piston, inner cylinder sliding inside the outer cylinder, earth and sand pressure feeding piston connected to the front end of the inner cylinder, inner cylinder pushing piston connected to the rear end of the inner cylinder, outer cylinder pushing Oil chamber formed between the rear end surface of the piston for use and the rear wall of the casing, a second oil chamber formed between the outer peripheral surface of the outer cylinder and the inner peripheral surface of the casing, and the inner cylinder pushing piston. A third oil chamber formed between the rear end surface and the front end surface of the outer cylinder pushing piston, a fourth oil chamber formed between the outer peripheral surface of the inner cylinder and the inner peripheral surface of the outer cylinder, In the oil chamber The first port of Jill casing,
A second port of the casing communicating with the second oil chamber, an oil passage communicating between the first oil chamber and the third oil chamber, an oil path communicating between the second oil chamber and the fourth oil chamber, and a first oil chamber and a third oil chamber. Hydraulic hose having a sediment pressure pump having a spool valve for opening and closing an oil passage between the first and second ports and a hydraulic operating unit including a hydraulic source and a directional switching valve installed on the ground, respectively, By supplying and discharging hydraulic oil through these oil passages, the outer cylinder of the sediment pump was advanced ahead of the sediment pump piston, and the sediment pump pipe was isolated from the sediment storage tank. Then, the earth and sand pump is advanced to push out the earth and sand taken in the outer cylinder to the earth and sand pipe, and after the earth and sand is fed, the operation cycle of retreating the outer cylinder and the earth and sand piston is repeated to excavate soil. And a slidable rod in the middle of an oil passage connecting the first port of the sediment pressure pump and the hydraulic operating part. With a built-in piston, the bottom-side oil chamber with a large cross-sectional area is
Dummy cylinders, each connecting a rod-side oil chamber with a small cross-sectional area to the oil passage on the hydraulic operation unit side, are installed. Through this dummy cylinder, supply of pressurized oil to the earth and sand pump during the forward process and during the reverse process It is characterized in that return oil is discharged from the earth and sand pressure pump.

[0024]

The dummy cylinder installed in the middle of the oil passage connecting the first port of the earth and sand pump and the hydraulic operating unit on the ground is connected to the oil passage on the earth and sand pump via the built-in piston with rod. Assuming that the bottom oil chamber has a cross-sectional area of A3 and the rod-side oil chamber has a cross-sectional area of A4, pressure is transmitted to and from the operation unit side oil passage. The oil amount corresponding to the product of the supply oil amount passing through the passage and A3 / A4 is supplied to the sediment pressure pump through the oil passage on the side of the sediment pressure pump.
It functions to discharge the amount of oil corresponding to the product of A4 / A3 and the amount of return oil passing through the oil passage on the earth and sand pressure pump side through the oil passage on the hydraulic operating unit side. By installing such a dummy cylinder in the vicinity of the sediment pressure pump, it is possible to operate the sediment pressure pump mounted on the small-diameter pipe propulsion device with the same amount of oil supplied from the hydraulic operation unit as before. As well as reducing the amount of oil returned to the hydraulic operating unit during the reverse process,
It becomes possible to reduce the pressure loss of the oil distribution passage.

[0025]

FIG. 1 is a hydraulic circuit diagram showing an embodiment of the present invention. The hydraulic circuit diagram of FIG. 2 showing the conventional example is different from the hydraulic circuit diagram of FIG. 2 only in that a dummy cylinder 101 is provided in the middle of the oil passage 44 (on the side close to the sediment pump 100). The basic configuration of the pumping device is the same, and the parts that are functionally equivalent to FIG.

FIG. 3 schematically shows the relationship between the earth and sand pump and the dummy cylinder for the sake of simplicity. FIG.
In the figure, 100 is a schematic diagram of a sediment pressure pump, 10
Reference numeral 1 denotes a dummy cylinder installed near the earth and sand pressure pump 100. The dummy cylinder 101 has a built-in slidable piston 102 with a rod, and a rod-side oil chamber 104 thereof.
Is connected to the direction switching valve 43 of the hydraulic operating unit 200 shown in FIG. 1 by an oil passage 44, and the bottom oil chamber 103 is connected to the first port 14 of the earth and sand pressure pump 100 by an oil passage 44a. In addition, the second port 1 of the sediment pump 100
5 and the direction switching valve 43 of the hydraulic operation unit 200 shown in FIG.

FIG. 4 is a schematic diagram showing a conventional earth and sand pumping apparatus.

The earth and sand pump 100 shown in FIGS. 3 and 4 is assumed to have the same size, and the stroke of the outer cylinder 18 in the forward and backward steps is S. Also, the cross-sectional area A1 of the first oil chamber 20 and the cross-sectional area A2 of the second oil chamber 21, the cross-sectional area A3 of the bottom oil chamber 103 of the dummy cylinder 101, and the rod-side oil chamber 104 of the earth and sand pressure pump 100 shown in FIG. Is assumed to be A1 / A2 = A3 / A4.

In FIGS. 3 and 4, the time from when pressurized oil is supplied to the first port 14 of the earth and sand pressure pump 100 to when the forward stroke of the outer cylinder 18 is completed at the stroke end, and thereafter, the direction switching valve 43 is turned on. If the sum of the time required to switch to supply the pressurized oil to the second port 15 of the earth and sand pressure pump 100 and to complete the retreating process of the outer cylinder 18 at the stroke end is defined as one cycle time of the outer cylinder 18,
One cycle time T1, T2 (sec) excluding the operation time of the direction switching valve 43 is the supply oil amount Q (cm ³ / min) of the oil passages 44, 45 and the oil chamber cross-sectional areas A1 to A4 (c).
m ³ ) and the stroke S (cm) are obtained as follows.

In FIG. 4, during the forward movement step, the oil amount Q (cm ³ / min) passing through the oil passage 44 is directly
Since it is supplied to the first port 14 of 0, one cycle time T1 can be expressed by the following equation.

[0031]

(Equation 1)

In FIG. 3, during the forward movement step, Qcm ³ /
min of pressurized oil, the supplied oil amount Qcm ³ / m
Since the oil amount corresponding to the product of in and A3 / A4 is supplied from the bottom oil chamber 103 of the dummy cylinder 101 to the first port 14 of the sediment pressure pump 100 through the oil passage 44a,
One cycle time T2 can be expressed by the following equation.

[0033]

(Equation 2)

Now, since A3 / A4 = A1 / A2,

Equation (2) can be rewritten as follows.

[0035]

(Equation 3)

Assuming that A3 / A4 = A1 / A2 = 3,

[Equation 1],

From Equation 3, T1 and T2 are as follows.

[0037]

(Equation 4)

[0038]

From the equation (4), when the one cycle time of the outer cylinder 18 is the same, in the apparatus of the present invention shown in FIG. 3, the supply oil amount Q of the oil passages 44 and 45 is 1 compared to the conventional example shown in FIG. / 2
Is good.

In the conventional example shown in FIG. 4, the amount of oil supplied through the oil passage 45 at the time of the retreating step is Qcm ³ / mi.
Assuming that n, the return oil amount passing through the oil passage 44 is ³ Qcm ³ / m
In the apparatus of the present invention shown in FIG. 3, the amount of oil supplied through the oil passage 45 is Qcm ³ / mi during the retreating step.
Assuming that n, the return oil amount passing through the oil passage 44 is equal to the product of the return oil amount 3Qcm ³ / min and A4 / A3 passing through the oil passage 44a, ie, Qcm ³ / min and the supply oil amount. 1-inch hydraulic hose is 1 /
Assuming a case where oil flow of 35 × 10 ³ cm ³ / min and a 300 m extension is performed, the pressure loss is 7 kgf / cm ²
), And the pressure loss in the oil passage 44 during the retreating process is significantly reduced as compared with the conventional example.)

During the forward process, the earth and sand pump 100
Assuming that the load pressure generated in the first oil chamber 20 is Pkgf / cm ² , a pressure of P × A3 / A4 is generated in the oil passage 44 in FIG. 3, but this is a load pressure for performing work. From
Does not become fever.

In the above description, A3 / A4 = A1 / A2 = 3
However, the area ratios of A1 / A2 and A3 / A4 are not limited to specific values, and A3 / A4
The relationship of = A1 / A2 is not necessarily restricted.

Next, the synchronous adjustment of the earth and sand pressure pump 100 and the dummy cylinder 101 will be described. In order for the dummy cylinder 101 shown in FIG. 3 to perform its function, the piston 102 must be able to reciprocate in synchronization with the forward and backward steps of the earth and sand pressure pump 100. FIG. 5 shows an example of a synchronization adjustment mechanism for restoring a case in which synchronization is lost due to oil leakage or the like in the dummy cylinder 101 during operation of the earth and sand pump. In FIG. 5, reference numeral 46a denotes a limit switch that is turned on at the stroke end of the piston 102 during the retreating step of the earth and sand pressure pump 100, and 46b is a limit switch that is turned on at the stroke end of the piston 102 during the forward step of the earth and sand pressure pump 100. Yes, these limit switches 46a, 46b
If the indicator lamps (not shown) on the operation panel are turned on at the time of the turning-on operation, it is understood that the dummy cylinders 101 are synchronized by repeating the blinking of both indicator lamps. If the indicator lamp on the side of the limit switch 46a does not light up, the oil between the sediment pressure pump 100 and the dummy cylinder 101 is supplied from the hydraulic source including the hydraulic pump 47 and the relief valve 48 through the switching valves 49 and 50 and the oil passage 51. When the road 44a is replenished with oil and the indicator light on the limit switch 46b side does not light up,
The switching valve 49 is switched to discharge excess oil from the oil passage 44a. After performing the synchronization adjustment in this manner, the switching valve 50
Is turned off. The hydraulic source for synchronization adjustment can be shared with a hydraulic source such as a direction correcting jack mounted on the small-diameter pipe propulsion device.

[0043]

According to the present invention, the earth and sand pressure pump mounted on the small-diameter pipe thruster can be reduced to the same amount as the conventional one by using a smaller amount of oil supplied from the hydraulic operating unit (theoretically, it can be halved). And the amount of oil returned to the hydraulic operating unit during the retreating process can be reduced to the same level as the supplied oil amount, so that the sediment pump and the hydraulic operating unit on the ground are connected. The pressure loss in the oil passage is reduced, and the propulsion distance can be increased without increasing the oil temperature or increasing the power loss.

Further, by selecting each area ratio of A1 / A2 and A3 / A4 so that the supply oil amount passing through the oil passage 44 and the return oil amount are equal, the thickness of the hydraulic hose of the oil passage 44 can be reduced. The capacity and the like of the direction switching valve 43 can be determined only by the supplied oil amount, and the apparatus can be economically constructed.

[Brief description of the drawings]

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

FIG. 2 is a hydraulic circuit diagram of a conventional example.

FIG. 3 is a schematic diagram for explaining the flow of oil into and out of the earth and sand pressure pump unit according to the present invention.

FIG. 4 is a schematic diagram for explaining the flow of oil into and out of a conventional earth and sand pressure pump unit.

FIG. 5 is a hydraulic circuit diagram showing an example of a dummy cylinder synchronization adjusting mechanism used in the earth and sand pressure feeding device of the present invention.

FIG. 6 is a vertical cross-sectional view of a sediment pump, in which (a) is CC.
FIG. 3B is a partial view on the left side of the line, and FIG. 3B is a partial view on the right side of the line CC.

FIG. 7 is a partially enlarged view of the earth and sand pressure pump.

FIG. 8 is a diagram showing the operation sequence of the earth and sand pump.
(C) is each state diagram.

FIG. 9 is a longitudinal sectional view of a small-diameter pipe propulsion device equipped with a sediment pump, (a) is a partial view on the left side of line DD, (b)
Is a partial view on the right side of the line DD.

[Explanation of symbols]

1 ... sediment storage tank, 8 ... sediment pumping pipe, 13 ... casing, 14 ... 1st port, 15 ... 2nd port, 18 ...
Outer cylinder, 19 ... Outer cylinder pushing piston, 2
0: first oil chamber, 21: second oil chamber, 29: inner cylinder,
Reference numeral 30: earth and sand pressure feeding piston, 31: piston for pushing the inner cylinder, 32: third oil chamber, 33: fourth oil chamber, 22, 23
... an oil passage between the first oil chamber 20 and the third oil chamber 32, 24 ... a spool valve, 26, 27, 29 ', 34 ... a second oil chamber 21 and a fourth oil chamber.
Oil passages between the oil chambers 33, 37 ... oil tanks, 39 ... hydraulic pumps, 43 ... directional switching valves, 44, 44a, 45 ... oil supply and discharge oil passages, 100 ... sediment pressure pumps, 101 ... dummy cylinders, 102 ... Piston with rod, 103 ... Bottom side oil chamber, 104 ... Rod side oil chamber, 200 ... Hydraulic operation unit, 300 ... Small diameter pipe propulsion machine.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Matsunaga 1-6-1, Uchisaiwai-cho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Masashi Miyatake 1-1-6, Uchisaiwai-cho, Chiyoda-ku, Tokyo Japan Nippon Telegraph and Telephone Corporation (72) Inventor Shusaku Katsura 1-6-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-A-4-360920 (JP, A) JP-A-60- 219334 (JP, A) JP-A-59-51171 (JP, A) JP-A-4-22591 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) E21D 9/12

Claims (2)

(57) [Claims] 1. A small-diameter pipe thruster, a cylindrical casing, an outer cylinder sliding in the casing, an outer cylinder pushing piston connected to a rear end of the outer cylinder, and sliding in the outer cylinder. Formed between the rear end surface of the inner cylinder, a sediment feeding piston connected to the front end of the inner cylinder, the inner cylinder pushing piston connected to the rear end of the inner cylinder, and the rear end surface of the outer cylinder pushing piston. A first oil chamber, a second oil chamber formed between the outer peripheral surface of the outer cylinder and the inner peripheral surface of the casing, between the rear end surface of the inner cylinder pushing piston and the front end surface of the outer cylinder pushing piston. A fourth oil chamber formed between the outer peripheral surface of the inner cylinder and the inner peripheral surface of the outer cylinder, a first port of a casing communicating with the first oil chamber,
A second port of the casing communicating with the second oil chamber, an oil passage communicating between the first oil chamber and the third oil chamber, an oil path communicating between the second oil chamber and the fourth oil chamber, and a first oil chamber and a third oil chamber. Hydraulic hose having a sediment pressure pump having a spool valve for opening and closing an oil passage between the first and second ports and a hydraulic operating unit including a hydraulic source and a directional switching valve installed on the ground, respectively, By supplying and discharging hydraulic oil through these oil passages, the outer cylinder of the sediment pump was advanced ahead of the sediment pump piston, and the sediment pump pipe was isolated from the sediment storage tank. Then, the earth and sand pump is advanced to push out the earth and sand taken in the outer cylinder to the earth and sand pipe, and after the earth and sand is fed, the operation cycle of retreating the outer cylinder and the earth and sand piston is repeated to excavate soil. And a slidable rod in the middle of an oil passage connecting the first port of the sediment pressure pump and the hydraulic operating part. With a built-in piston, the bottom-side oil chamber with a large cross-sectional area is
Dummy cylinders, each connecting a rod-side oil chamber with a small cross-sectional area to the oil passage on the hydraulic operation unit side, are installed. Through this dummy cylinder, supply of pressurized oil to the earth and sand A sediment pumping device for small-diameter pipe propulsion machines, wherein return oil is discharged from a sediment pump. 2. A sectional area A1 of a first oil chamber of a sediment pressure pump.
And a sectional area A2 of the second oil chamber and a sectional area A3 of the bottom oil chamber of the dummy cylinder and a sectional area A4 of the rod-side oil chamber of the dummy cylinder, wherein A1 / A2 = A3 / A4. Item 2. A sediment pumping device for a small-diameter pipe propulsion device according to Item 1.