JPH0742490A - Sand pumping device for small diameter pipe thrusting machine - Google Patents

Abstract

PURPOSE:To reduce the pressure loss of hydraulic path connecting a sand pump and a hydraulic operation disk on the ground to extend the thrusting distance and reduce the equipment cost like hydraulic hoses, directional changeover valves, etc., by actuating the sand pump mounted on a small diameter pipe thrusting machine at the same capacity with conventional cases with less quantity of supply oil and reducing the returning oil in the retreat process. CONSTITUTION:The rod side hydraulic chamber 104 of a dummy cylinder 101 equipped on the way of hydraulic path connecting the first port 14 and a hydraulic operating disk 200 of a sand pump 100 is connected to a hydraulic operation disk side hydraulic path 44 and the bottom side hydraulic chamber 103 thereof is connected to the sand pump side hydraulic path 44a respectively. The hydraulic oil is supplied in the forward movement process of the sand pump 100 and discharged in the retreat process thereof through the dummy cylinder 101.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an earth and sand pumping device for sending and discharging excavated earth and sand from a small diameter pipe propulsion device to the ground.

[0002]

2. Description of the Related Art As a typical example of the earth and sand pumping device for a small diameter pipe propulsion machine, there is one disclosed in Japanese Patent Laid-Open No. 59-51171. This earth and sand pumping device is composed of a earth and sand pump for pumping installed in a small-diameter pipe propulsion device and a hydraulic operating unit installed on the ground.

As shown in FIGS. 6 and 7, the earth and sand pressure pump 100 comprises a cylindrical casing 13, an outer cylinder 18 sliding inside the casing 13, and an outer cylinder 1.
Piston 1 for pushing the outer cylinder connected to the rear end of 8
9, an inner cylinder 29 that slides in the outer cylinder 18,
Earth and sand pressure feeding piston 30 connected to the front end of the inner cylinder 29, inner cylinder pushing piston 31 connected to the rear end of the inner cylinder 29, outer cylinder pushing piston 1
9 formed between the rear end surface of the casing 9 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 circumferential surface of the inner cylinder 3 and the third oil chamber 32 formed between the rear end surface of the inner cylinder pushing piston 31 and the 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, a first port 14 of the casing 13 communicating with the first oil chamber 20, and a casing communicating with the second oil chamber 21. 13, the second port 15, the oil passages 22 and 23 connecting the first oil chamber 20 and the third oil chamber 32, and the oil passages 26 and 27 connecting the second oil chamber 21 and the fourth oil chamber 33. , 2
9 ', 34 and spool valves 24 for opening and closing the oil passages 22, 23 are provided.

In FIGS. 6 and 7, reference numeral 1 is a sediment reservoir tank, 2 is an opening portion of the sediment reservoir tank 1 to which sediment 36 is supplied, 3 is a sediment inlet port in the sediment reservoir tank 1,
4 and 5 are the side walls of the sand 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 pumping piston 30, 7 a rear wall of the oil tank 6, 8 a earth and sand pressure feeding pipe, 9 a flange for connecting the earth and sand pressure feeding pipe 8, 10 a seal casing, Reference numeral 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 for the outer cylinder 18, and 25 is an oil passage 2.
2 is a throttle provided at 2, a stopper 28 for the outer cylinder pushing piston 19, and 35 is a stopper for the inner cylinder pushing piston 31.

FIG. 2 is a hydraulic circuit diagram of a conventional example for operating the earth and sand pressure feed pump 100. The earth and sand pressure feed pump 100 installed in the small-diameter pipe propulsion machine is above the line AA in FIG.
The hydraulic operation unit 2 installed on the ground below the line B-B
Indicates 00.

The hydraulic operating unit 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 the direction switching valve 43.

44, 4 between lines A--A and B--B in FIG.
Reference numeral 5 denotes a first port 14, a second port 15 and a hydraulic operating unit 20 provided in the casing 13 of the earth and sand pressure pump 100.
The oil passage which connects between 0 and the direction switching valve 43 is shown. These oil passages 44 and 45 are sequentially connected and extended together with the propulsion of the small-diameter pipe propelling machine, and normally hydraulic hoses with joints are used at both ends of the same length as the buried pipe.

FIG. 8 shows the operation sequence of the earth and sand pressure pump 100. In the forward movement 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 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 pressure oil is supplied to the first oil chamber 20 through the oil passage 44 and the first port 14, the outer cylinder pushing piston 19 is pushed forward from the state shown in FIG. The outer cylinder 18 is advanced prior to 30. The outer cylinder 18 moves forward while taking in the earth and sand in the vicinity of the earth and sand inlet 3 of the earth and sand reservoir tank 1,
At the same time that the outer cylinder pushing piston 19 abuts on the stopper 28, the tip portion 18 'of the outer cylinder 18 is brought 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 abuts on the stopper 28, the spool valve 24 mounted on the piston 19 is pushed rearward by the stopper 28 to connect the oil passages 22 and 23. Then, 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 into the second oil chamber 21 through the oil passages 22 and 23. The earth and sand pressure feeding piston 30 moves forward together with the inner cylinder 29 to push the earth and sand 36 taken into the outer cylinder 18 to the earth and sand pressure feeding pipe 8 for pressure feeding. Meanwhile, the oil in the fourth oil chamber 33 is in the oil passage 3
4, 29 ', 27, 26, second oil chamber 21, second port 1
5, returned to the oil tank 37 through the oil passage 45.

The oil chambers 20 and 3 generated at the end of the forward movement process in which the inner cylinder pushing piston 31 contacts the stopper 35.
2 and the pressure increase in the oil passage 44 is detected by a pressure detector (not shown), the signal causes the solenoid 43b of the directional control valve 43 to be energized instead of the solenoid 43a.
The direction switching valve 43 is switched to a position connecting the oil passage 40 and the oil passage 45 and the oil passage 41 and the oil passage 44. As a result, the earth and sand pressure pump 100 moves to the retracting step. 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 hydraulic pressure moves the spool valve 24 further rearward to close the oil passages 22 and 23 and to push the outer cylinder. The piston 19 is pushed backwards 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.

At the same time that the outer cylinder pushing piston 19 comes into contact with the rear wall of the casing 13 and stops, the spool valve 24 also comes into contact with the rear wall of the casing 13 and is pushed forward to connect the oil passages 22 and 23. After that, the second oil chamber 2
1 through the oil passages 26, 27, 29 'and 34 to the fourth oil chamber 3
Piston 3 for pushing the inner cylinder by pressure oil flowing into 3
1 is pushed backward, and the earth and sand pumping piston 30 is retracted together with the inner cylinder 29. Meanwhile, the oil in the third oil chamber 32 receives the oil passages 28, 22, the first oil chamber 20, the first port 14,
It is returned to the oil tank 37 through the oil passage 44.

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 surface of the outer cylinder pushing piston 19 When a pressure detector (not shown) detects a pressure increase in the oil passages 21, 33 and the oil passage 45, the signal causes the solenoid 43b of the directional control valve 43 to be released.
Instead, the solenoid 43a is energized, and the earth and sand pressure pump 100 moves to the advance process again. At this time, the first oil chamber 2
The spool valve 24 is pushed further forward by the pressure oil supplied to 0, and the state between the oil passages 22 and 23 is closed as shown in FIG. 7. By repeating the above operation cycle, the earth and sand pressure pump 100 intermittently pressure-feeds the earth and sand.

[0013]

FIG. 9 shows an overall cross section of a small-diameter pipe propulsion device 300 equipped with the above-mentioned earth and sand pressure pump. This small-diameter pipe propulsion machine 300 excavates the ground G at the rotary excavation section 302 provided at the tip of the propulsion body 301, and at the same time, excavates with a viscosity imparting liquid such as bentonite solution injected from the injection port 303 of the rotary excavation section. The earth and sand pressure pump 10 in which the earth and sand is stirred and mixed to form mud having plastic flowability, and the excavated earth and sand is installed in the propulsion machine body 301 through the earth and sand passage 304 between the propulsion machine body 301 and the ground.
No. 0 in the earth and sand reservoir tank 1, the outer cylinder 18 and the earth and sand pressure feeding piston 30 are sequentially operated to press and discharge the earth through the earth and sand pressure feeding pipe 8, and the thruster main body 301 is followed by the thruster installed in the starting shaft. Buried pipe 3
No. 05 is promoted to sequentially bury the pipe in the ground (see Japanese Patent Laid-Open No. 1-263386).

In the small-diameter pipe propulsion machine having the structure shown in FIG. 9 in which a part of the excavated earth and sand that has become mud is 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 a lubricant. It has been proved in actual construction that it has a role and that the required thrust is significantly reduced compared to other methods of small diameter pipe propulsion. The propulsion distance of a small-diameter pipe propulsion machine is limited by the compressive strength or buckling strength of the buried pipe.
It is about m. On the other hand, the small-diameter tube propulsion machine having the structure shown in FIG. 9 can prolong the propulsion distance by a large reduction in the required thrust, and has a propulsion record of 200 m or more per span.

A long propulsion distance has great merit in construction such as reduction of starting shaft, and therefore a longer distance is desired.

The small-diameter pipe propulsion machine having the structure shown in FIG. 9 has been confirmed in the past to have no problem in thrust even when the propulsion distance is 200 m or more, but it is attempted to extend the propulsion distance to about 300 m in the future. In that case, it was found that the propulsion distance was limited by the pressure loss of the oil passage connecting the earth and sand pressure pump and the hydraulic operation unit on the ground. The circumstances 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 not possible in space to install the whole earth and sand pumping device including the hydraulic operating portion, and as shown in FIG. A hydraulic operation unit 200 in which only the earth and sand pressure pump 100 is installed in the machine and which includes a hydraulic power source and a direction switching valve
Is installed on the ground, and an oil passage 4 such as a hydraulic hose that passes between the earth and sand pressure pump 100 and the hydraulic operation unit 200 in an embedded pipe.
There is no choice but to take the method of connecting with 4,45. In this case, as the propulsion distance increases, the oil passages 44,
45 also becomes long.

In the earth and sand pumping apparatus for a small diameter pipe propelling machine as described above, the cross-sectional area of the first oil chamber 20 is equal to the pressure receiving area of the outer cylinder pushing piston 19 during the forward movement step of the earth and sand pumping pump 100 shown in FIG. (This area is designated as A1). Further, during the backward movement process, 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 referred to as A2). Due to structural factors, there is an area difference of about A1 / A2≈3 between the pressure receiving area A1 during the forward movement process and the pressure receiving area A2 during the backward movement process. Therefore, when the amount of oil supplied to the first port 14 through the oil passage 44 during the forward stroke is Qcm ³ / min, the second port 1
The amount of oil discharged from No. 5 through the oil passage 45 to the oil tank 37 is about Q / 3 cm ³ / min. In addition, the amount of oil supplied to the second port 15 through the oil passage 45 during the retreating process is set to Qc.
Assuming m ³ / min, the amount of oil discharged from the first port 14 through the oil passage 44 to the oil tank 37 during that time is about 3 Qc.
It becomes m ³ / min.

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

If the thickness of the hydraulic hose of the oil passage 44 that can be easily connected manually is 1 inch and the amount of oil supplied to the earth and sand pressure pump 100 is 70 × 10 ³ cm ³ / min, the retreat step is performed. The amount of oil returned through the oil passage 44 is about 21
Since 0 × 10 ³ cm ³ / min and the flow velocity in the oil passage 44 is about 6.9 m / sec, when the oil passage 44 is extended to 300 m, the pressure loss of the hydraulic hose excluding the joint portion 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.
Since it is set to kgf / cm ² , the oil passage 44 during the retreat process
It can be seen that when the pressure loss of ² is 200 kgf / cm ² or more, the normal earth and sand pressure pump cannot operate, 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 above the pressure loss, but all the pressure loss in the oil passage 44 during the retreating process becomes heat, and the oil temperature rises. The increase of loss is not preferable from the viewpoint of hydraulic circuit and power loss.

The present invention has been made in view of the above points. The earth and sand pressure pump installed in the small diameter pipe propulsion machine is operated in the same manner as the conventional one with a smaller amount of oil supplied from the hydraulic operating section, and is retracted. By reducing the amount of oil returned to the hydraulic operation unit during the process, the pressure loss of the oil passage connecting the sediment pressure pump and the hydraulic operation unit on the ground can be reduced, the propulsion distance can be extended, and the sediment pressure device can be used. The purpose is to eliminate the waste in terms of equipment and to economically configure the device.

[0023]

In order to achieve the above object, the present invention relates to a small-diameter pipe propelling machine, which is connected to a cylindrical casing, an outer cylinder sliding in the casing, and a rear end portion of the outer cylinder. Outer cylinder pushing piston, inner cylinder sliding inside the outer cylinder, earth and sand pumping 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 A first oil chamber formed between the rear end surface of the working piston 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, and a first oil chamber. In the oil chamber The first port of Jill casing,
The second port of the casing leading to the second oil chamber, the oil passages connecting the first oil chamber and the third oil chamber, the second oil chamber and the fourth oil chamber, and the first oil chamber and the third oil chamber. A hydraulic hose that installs a sediment pressure pump having a spool valve that opens and closes an oil passage between the first and second ports, and connects the first and second ports thereof to a hydraulic power source installed on the ground and a hydraulic operation unit including a direction switching valve, respectively. Etc., and by supplying and discharging hydraulic oil through these oil passages, the outer cylinder of the earth and sand pump is advanced before the earth and sand piston and the earth and sand pump pipe is isolated from the earth and sand reservoir tank. After that, the earth and sand pumping piston is moved forward to push the earth and sand taken into the outer cylinder to the earth and sand pump, and after the earth and sand is sent, the outer cylinder and earth and sand piston are retracted. In the earth and sand pumping apparatus for a small-diameter pipe propulsion machine configured to perform the above-mentioned pressure-feeding and discharging, a slidable rod is provided in the middle of an oil passage connecting between the first port of the earth-and-sand pressure pump and the hydraulic operating unit. With a built-in piston, the bottom side oil chamber with a large cross-sectional area is installed in the oil passage on the earth and sand pressure pump side.
A dummy cylinder is installed in which the rod-side oil chamber with a small cross-sectional area is connected to the oil passage on the hydraulic operating part side.The dummy cylinder is used to supply pressure oil to the earth and sand pump during the forward stroke and during the backward stroke. The feature is that the return oil is discharged from the sediment pump.

[0024]

[Operation] The dummy cylinder installed in the middle of the oil passage connecting the first port of the earth and sand pressure pump and the hydraulic operation part on the ground is connected to the oil passage of the earth and sand pressure pump via the built-in piston with rod. When pressure is transmitted to the oil passage on the operating portion side, and the cross-sectional area of the bottom oil chamber is A3 and the cross-sectional area of the rod oil chamber is A4, the oil on the hydraulic operating portion side is moved during the forward movement process of the earth and sand pressure pump. An oil amount corresponding to the product of the amount of oil supplied through the channel and A3 / A4 is supplied to the earth and sand pressure pump through the earth and sand pressure pump side oil passage, and during the retreat step of the earth and sand pressure pump,
It functions to discharge the amount of oil corresponding to the product of A4 / A3 and the amount of oil returned through the oil passage on the earth and sand pressure pump side through the oil passage on the hydraulic operation part side. By installing such a dummy cylinder near the earth and sand pump, it is possible to operate the earth and sand pump installed in the small-diameter pipe propulsion machine with a smaller amount of oil supplied from the hydraulic operating unit in the same manner as in the past. Along with being able to reduce the amount of oil returned to the hydraulic operating unit during the reverse process,
It is possible to reduce the pressure loss in the oil 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 only in that a dummy cylinder 101 is installed in the middle of the oil passage 44 (on the side close to the earth and sand pressure pump 100). The basic structure of the pumping device is the same, and the parts functionally equivalent to those in FIG. 2 are designated by the same reference numerals.

In order to simplify the explanation, the relationship between the earth and sand pressure pump and the dummy cylinder is schematically shown in FIG. Figure 3
In the figure, 100 is a schematic diagram of the earth and sand pressure pump, 10
Reference numeral 1 is a dummy cylinder installed near the earth and sand pressure pump 100. The dummy cylinder 101 has a built-in slidable rod-equipped piston 102, and the rod-side oil chamber 104
Is connected to the direction switching valve 43 of the hydraulic operating unit 200 shown in FIG. 1 by the 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 the oil passage 44a. Also, 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. 1 are connected by an oil passage 45.

FIG. 4 is a schematic view showing a conventional soil pressure pumping apparatus.

The earth and sand pressure pump 100 shown in FIGS. 3 and 4 is assumed to have the same size, and the stroke of the forward stroke and backward stroke of the outer cylinder 18 is S. Further, 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 pump 100 shown in FIG. It is assumed that the area ratios of the cross-sectional areas A4 of A1 / A2 = A3 / A4.

In FIGS. 3 and 4, the time until the pressure oil is supplied to the first port 14 of the earth and sand pressure pump 100 to complete the forward stroke process of the outer cylinder 18 at the stroke end, and then the direction switching valve 43 is set. When the sum of the time until the outer cylinder 18 is switched and the pressure oil is supplied to the second port 15 of the earth and sand pressure pump 100 to complete the retreat process of the outer cylinder 18 at the stroke end, one cycle time of the outer cylinder 18 is obtained.
Each one cycle time T1, T2 (sec) excluding the operation time of the directional control valve 43 is the oil supply 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 process, the amount of oil Q (cm ³ / min) passing through the oil passage 44 is kept as it is and the earth and sand pressure pump 10 is used.
Since it is supplied to the first port 14 of 0, the one cycle time T1 can be expressed by the following equation.

[0031]

[Equation 1]

In FIG. 3, during the forward movement process, Qcm ³ / Q is introduced into the rod side oil chamber 104 of the dummy cylinder 101 through the oil passage 44.
When the pressure oil of min is supplied, the amount of the supplied oil Qcm ³ / m
Since an oil amount corresponding to the product of in and A3 / A4 is supplied from the bottom side oil chamber 103 of the dummy cylinder 101 through the oil passage 44a to the first port 14 of the earth and sand pressure pump 100,
One cycle time T2 can be expressed by the following equation.

[0033]

[Equation 2]

Since A3 / A4 = A1 / A2 now,

Equation 2 can be rewritten as follows.

[0035]

[Equation 3]

If A3 / A4 = A1 / A2 = 3, then

[Equation 1],

From Equation 3, T1 and T2 are as follows.

[0037]

[Equation 4]

[0038]

[Mathematical formula-see original document] When the one cycle time of the outer cylinder 18 is the same, the amount Q of oil supplied to the oil passages 44 and 45 is 1 in the device of the present invention shown in FIG. 3 compared to the conventional example shown in FIG. / 2
I know that is good.

Further, in the conventional example shown in FIG. 4, the amount of oil supplied through the oil passage 45 is set to Qcm ³ / mi during the backward movement process.
n, the amount of return oil 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 backward movement process.
n, the return oil amount passing through the oil passage 44 becomes equal to the product of the return oil amount 3Qcm ³ / min passing through the oil passage 44a and A4 / A3, that is, Qcm ³ / min and the supply oil amount (temporarily, 1 inch hydraulic hose
Assuming a case where the oil quantity of 2 is 35 × 10 ³ cm ³ / min and is extended by 300 m, the pressure loss is 7 kgf / cm ²
The pressure loss in the oil passage 44 during the retreating process is significantly reduced compared to the conventional example).

During the forward movement process, the earth and sand pressure 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 of FIG. 3, which is a load pressure for performing work. From
It doesn't turn into heat.

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 fulfill 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 repairing a situation where oil is leaked in the dummy cylinder 101 and synchronization is lost during operation of the earth and sand pressure pump. In FIG. 5, 46a is a limit switch that is turned on at the stroke end of the piston 102 during the backward movement process 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 movement process of the earth and sand pressure pump 100. Yes, these limit switches 46a, 46b
When the indicator lamps (not shown) on the operation panel are turned on during the ON operation of, both of the indicator lamps blink repeatedly, and it is understood that the dummy cylinders 101 are synchronized. If the indicator light on the side of the limit switch 46a does not light up, the oil between the earth and sand pressure pump 100 and the dummy cylinder 101 is passed from the hydraulic source consisting of the hydraulic pump 47 and the relief valve 48 through the switching valves 49 and 50 and the oil passage 51. When oil is supplied to the passage 44a 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 way, the switching valve 50
Is turned off. The hydraulic power source for synchronous adjustment can be shared with the hydraulic power source such as the direction correction jack mounted on the small diameter pipe propulsion machine.

[0043]

EFFECTS OF THE INVENTION According to the present invention, the earth and sand pressure feed pump mounted on the small diameter pipe propulsion machine is equivalent to the conventional one with a smaller amount of oil supplied from the hydraulic operating section (theoretically, half of the conventional oil supply is possible). It is possible to reduce the amount of oil returned to the hydraulic operation unit during the reverse stroke to the same level as the amount of oil supplied, so connect the soil pressure pump and the hydraulic operation unit on the ground. The pressure loss of the oil passage is reduced, and the propulsion distance can be extended without increasing the oil temperature and the power loss.

Further, by selecting the area ratios A1 / A2, A3 / A4 so that the amount of supply oil and the amount of return oil passing through the oil passage 44 become equal, the thickness of the hydraulic hose in the oil passage 44, Since the capacity of the directional control valve 43 and the like can be determined only by the amount of supplied oil, the device can be economically constructed.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram showing an 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 inflow and outflow of oil to and from the earth and sand pumping unit of the present invention.

[Fig. 4] Fig. 4 is a schematic diagram for explaining oil in and out of a soil and sand pressure pump unit of a conventional example.

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

FIG. 6 is a vertical cross-sectional view of a sand and sand pump, in which (a) is CC.
Partial view on the left side of the line, (b) is a partial view on the right side of the line C-C.

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

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

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

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Sediment collection tank, 8 ... Sediment pressure feeding pipe, 13 ... Casing, 14 ... 1st port, 15 ... 2nd port, 18 ...
Outer cylinder, 19 ... Outer cylinder pushing piston, 2
0 ... 1st oil chamber, 21 ... 2nd oil chamber, 29 ... inner cylinder,
30 ... earth and sand pressure feeding piston, 31 ... inner cylinder pushing piston, 32 ... third oil chamber, 33 ... fourth oil chamber, 22, 23
... oil passage between first oil chamber 20 and third oil chamber 32, 24 ... spool valve, 26, 27, 29 ', 34 ... second oil chamber 21 and fourth
Oil passage between oil chambers 33, 37 ... Oil tank, 39 ... Hydraulic pump, 43 ... Direction switching valve, 44, 44a, 45 ... Oil supply and discharge oil passage, 100 ... Sediment pressure pump, 101 ... Dummy cylinder, 102 ... piston with rod, 103 ... oil chamber on the bottom side, 104 ... oil chamber on the rod side, 200 ... hydraulic operating unit, 300 ... small diameter pipe propulsion machine.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroshi Matsunaga 1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation (72) Masashi Miyatake 1-6-1, Uchisaiwaicho, Chiyoda-ku, Tokyo Nihonhon Telegraph and Telephone Corp. (72) Inventor Shusaku Katsura 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corp.

Claims (2)

[Claims] 1. A small-diameter pipe propelling machine, a cylindrical casing, an outer cylinder sliding in the casing, an outer cylinder pushing piston connected to a rear end portion of the outer cylinder, and an outer cylinder sliding. It is formed between the inner cylinder, the earth and sand pumping 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 and the rear wall of the casing. 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 third oil chamber formed in, 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 the casing communicating with the first oil chamber,
The second port of the casing leading to the second oil chamber, the oil passages connecting the first oil chamber and the third oil chamber, the second oil chamber and the fourth oil chamber, respectively, and the first oil chamber and the third oil chamber. A hydraulic hose that installs a sediment pressure pump having a spool valve that opens and closes an oil passage between the first and second ports, and connects the first and second ports thereof to a hydraulic power source installed on the ground and a hydraulic operation unit including a direction switching valve, respectively. Etc., and by supplying and discharging hydraulic oil through these oil passages, the outer cylinder of the earth and sand pump is advanced before the earth and sand piston and the earth and sand pump pipe is isolated from the earth and sand reservoir tank. After that, the earth and sand pumping piston is moved forward to push the earth and sand taken into the outer cylinder to the earth and sand pump, and after the earth and sand is sent, the outer cylinder and earth and sand piston are retracted. In the earth and sand pumping apparatus for a small-diameter pipe propulsion machine configured to perform the above-mentioned pressure-feeding and discharging, a slidable rod is provided in the middle of an oil passage connecting between the first port of the earth-and-sand pressure pump and the hydraulic operating unit. With a built-in piston, the bottom side oil chamber with a large cross-sectional area is installed in the oil passage on the earth and sand pressure pump side.
A dummy cylinder is installed in which the oil chamber on the rod side with a small cross-sectional area is connected to the oil passage on the hydraulic operating part side, respectively. A sediment pumping device for a small diameter pipe propulsion device, characterized in that return oil is discharged from the sediment pump. 2. A cross-sectional area A1 of the first oil chamber of the earth and sand pump.
And the sectional area A2 of the second oil chamber, the sectional area A3 of the bottom side oil chamber of the dummy cylinder and the sectional area A4 of the rod side oil chamber are A1 / A2 = A3 / A4. Item 1. The earth and sand pumping device for a small diameter pipe propulsion machine according to Item 1.