JP4767190B2 - Fluid pressure cylinder expansion head with built-in accumulator and expansion blade holding method using the same - Google Patents

Description

  The present invention relates to an expansion head provided at a lower end portion of a drilling work rod such as a drilling screw rod and a drilling agitation rod, and relates to an expansion head incorporating an accumulator together with a fluid pressure cylinder, and an expansion blade holding method using the same.

  Conventionally, as a hydraulic cylinder type expansion head, a double-acting hydraulic cylinder is built in the head rod, and two oil passages are vertically connected to the drilling screw rod to supply and discharge hydraulic pressure to the cylinder. ing. However, with this conventional head, when the drilling screw rod needs to be added, the structure of the screw rod extension connecting portion becomes complicated and large, resulting in a narrow space for conveying the excavated soil on the outer periphery of the screw rod connecting portion. There was a drawback that reduced the function. (Patent Document 1)

  In order to eliminate the above-mentioned drawbacks, a single-acting hydraulic cylinder with a spring wound in the cylinder was built in the head rod, and one oil passage was vertically connected to the screw rod. It was. However, this development head is a spring force in the cylinder that holds the expansion position of the expansion blade against earth pressure resistance, excavation resistance, etc. when the expansion head moves up and down, so sometimes the expansion blade is planned There are cases where outside expansion / contraction is performed, and in order to prevent this, there has been a problem that it is necessary to strengthen and enlarge the spring. (Patent Document 2)

  Therefore, the present inventors have a hydraulic cylinder without a spring and one system oil flow path, a piston-side space having a wide piston pressure receiving surface that receives hydraulic pressure across the piston, and A rod-side space having a narrow piston pressure receiving surface is formed, and the above-mentioned one-system oil flow path is branched and connected to both spaces via a spring-incorporated pilot check valve. It has been proposed that the cylinder is driven by a large pressing force exerted on the wide pressure receiving surface to expand the expansion blade, and that the expansion blade is closed and contracted by applying an external force such as earth pressure resistance to the expansion blade. (Patent Document 3)

  However, since the proposed head first drives the cylinder by the pressing force derived from the difference in pressure receiving area between the wide piston pressure receiving surface and the narrow piston pressure receiving surface, the normal hydraulic pressure capable of producing an equivalent driving force is obtained. Compared with the cylinder, the cylinder has a large diameter, and the head rod incorporating the cylinder also has a large diameter. As a result, there has been a drawback in that the space for excavating sediment around the head rod is reduced.

Also, when the expansion wing is closed and contracted by earth pressure resistance, the inner wall surface of the vertical hole is destroyed by the expansion wing, and as a result, in the case of soil cement pile construction, there is a disadvantage such as causing partial deterioration of the pile, Furthermore, in each pilot check valve on the branch path connected to the piston side space and rod side space of the hydraulic cylinder, the springs in the interior are adjusted weakly to ensure that both pilot check valves are opened with pilot pressure. There is a need. However, when excavating to a depth of several tens of meters, high head pressure is generated in a long oil passage extending from the ground to the hydraulic cylinder, which acts on the weak spring of the pilot check valve to open the check valve unexpectedly. As a result, there also remains a problem that the expansion wing cannot be maintained at a predetermined opening.
JP 2003-322890 A Shoko Sho 62-35745 JP 2005-315053 A

  The first invention of the present application is provided with a fluid pressure cylinder without a spring and a single fluid flow path for the expansion drive of the expansion blade, while suppressing the enlargement of the diameter of the fluid pressure cylinder, and the expansion blade by the earth pressure resistance or the like It is an object to prevent vertical hole collapse as much as possible when closing.

  It is an object of the second invention of the present application to reliably expand and hold the expansion blade at a desired expansion opening even when water head pressure is generated in the fluid flow path.

In order to solve the above problems, the first invention of the present application is
A hydraulic cylinder is incorporated in the head rod at the lower end of the excavation work rod, and a fluid flow path for supplying and discharging pressure fluid from the outside to the cylinder is vertically passed through the excavation work rod. In the configuration in which the expansion blade is supported to be freely expandable and contractable at the part, and the expansion and contraction of the fluid pressure cylinder and the expansion and contraction of the expansion blade are connected to each other,
A fluid pressure circuit which is disposed outside the at least one fluid flow path and has at least a fluid pressure pump, a pressure fluid supply / discharge valve to the fluid flow path, and a flow meter for the fluid to be supplied;
Either one of the piston-side space and the rod-side space in the fluid pressure cylinder and the one-system fluid flow path are connected so as to freely supply and discharge pressure fluid;
An accumulator is built in the head rod, and a pressure accumulator chamber of the accumulator is connected to the other space in the fluid pressure cylinder,
A counter balance valve having the supplied fluid pressure as a pilot pressure is connected between the other space in the fluid pressure cylinder and the pressure accumulating chamber,
The expansion blade is expanded by supplying a pressure fluid to one space of the fluid pressure cylinder, in which case the fluid in the other space is sent to the pressure accumulating chamber to accumulate pressure,
The pressure fluid supply / discharge valve and the counter balance valve supply the pressure fluid necessary to expand the expansion blade to one space of the fluid pressure cylinder, and the expansion blade expands to a desired expansion opening. The pressure fluid supply / discharge valve and the counter balance valve are immediately closed in such a state that the fluid in both the piston-side and rod-side spaces in the fluid pressure cylinder is confined to hold the expanding blade at the opening degree. And
We propose a fluid pressure cylinder expansion head with a built-in accumulator.

The second invention of the present application is
A fluid pressure circuit which is disposed outside and has at least a fluid pressure pump, a pressure fluid supply / discharge valve to the fluid passage, and a flow meter for the fluid to be supplied is connected to the one fluid passage in the first invention. Furthermore, a fluid pressure cylinder type expansion head with a built-in accumulator, in which a counter balance valve using the supplied fluid pressure as a pilot pressure is connected between the other space in the fluid pressure cylinder and the pressure accumulating chamber, is used. ,
The pressure fluid supply / discharge valve is opened, and the flow meter supplies the amount of pressure fluid necessary to expand the expansion blade to a desired expansion opening to one space of the fluid pressure cylinder.
When the expansion blade expands to the desired expansion opening, the pressure fluid supply / discharge valve is immediately closed, and the counter balance valve is also closed accordingly, so that both the piston side and rod side spaces in the fluid pressure cylinder are closed. The above-mentioned expanding blade is held at its opening by confining the fluid of
A method for holding the enlarged wing is proposed.

According to the expansion blade holding method using the fluid pressure cylinder type expansion head incorporating the accumulator of the first invention of the present application and the fluid pressure cylinder type expansion head incorporating the accumulator of the second invention of the present application , the flow meter is detected and the required amount When the expansion fluid is supplied to one space of the cylinder and the expansion blade is opened to a desired expansion opening, the pressure fluid supply / discharge valve and the counter balance valve are immediately closed, and the piston side in the cylinder and By confining the fluid in both spaces on the rod side, the expansion wing can be held at the above-mentioned expansion opening, which is affected even if high head pressure is generated in a long fluid flow path from the ground. There is nothing to do.

The “fluid pressure” in the present invention includes oil pressure, water pressure, and other fluid pressures.
Further, the “fluid pressure cylinder” may be either a piston fixed cylinder in which a piston is fixed and a tube is reciprocated, or a tube fixed cylinder in which a tube is fixed and a piston is reciprocated.
Furthermore, the “accumulator” includes a gas compression type, a spring type, and the like as a pressure accumulation method, and a piston type, a diaphragm type, a metal bellows type, and the like are selectively used for the gas compression type.

  An embodiment of the first invention of the present application will be described in detail with reference to the drawings. FIG. 1 shows an example implemented in the enlarged head (1) at the lower end of the screw rod (S). A round hole guide hole (3) having a lower end opening is formed in the upper half of the head rod (2). A piston-fixed hydraulic cylinder (4) is coaxially incorporated in the guide hole (3), and an air compression piston accumulator (5) is incorporated in the upper end of the head rod (2).

  The hydraulic cylinder (4) inserts and supports the tube (6) in the guide hole (3) so as to be slidable in the rod axis direction, and the piston rod (8) of the piston (7) is supported by the tube. The upper end plate of (6) is inserted and fixed in the upper end portion of the head rod (2).

  The accumulator (5) has a cylindrical pressure accumulation chamber (9) built therein, and a piston (10) is slidably fitted in the chamber (9) in the axial direction of the pressure accumulation chamber (9). ) Is divided into an air chamber (11) and an oil chamber (12), and the air chamber (11) is filled with air.

  The support structure of the enlarged blades (13) and (13) driven by the hydraulic cylinder (4) is as follows. In the head rod (2), a pair of brackets (14) and (14) are provided near the lower end of the opening of the guide hole (3) at positions opposed to each other in the diametrical direction. 14), the fan-shaped expansion wings (13) and (13) composed of both long and short arms are swung on the plane passing through the head rod axis line by the pins (15) and (15) at the bent portions. It is pivotally supported.

On the other hand, a short cylindrical operation block (16) having a slightly smaller diameter than that of the tube (6) is coaxially provided on the lower end surface of the cylinder tube (6), and the operation block (16) is shown in FIG. The axial direction of the operating block (16) while passing through the slide hole (17) having a rectangular cross section in the diametrical direction and partially opening the left side surface and the right side surface of the slide hole (17) on both sides of the slide hole (17). Guide grooves (18), (18) are formed in the slide hole (17), and the height of the slide (17) is equal to that of the slide (17). Two slide plates (19), (19) having a thickness of slidably inserted into each other with the plate surfaces slidable back to back, and the expansion wings (13), (13) The short arms (13 ′) and (13 ′) of the guide grooves (18) and (1 ) In the inserted state in, the slide plate (19), the pin (20) to (19), are connected by (20).

  The whole pressure oil supply / discharge device including the hydraulic cylinder (4) and the accumulator (5) is as follows. First, the oil rod (S) of one system is vertically passed through the screw rod (S), and the connecting pipe (22) provided at the upper end of the head rod (2) is connected to the channel (21). The other end of the oil flow path (23) connected to the lower end of the connection pipe (22) passes through the upper end of the head rod (2), the piston rod (8), and then the piston (7). 6) The other end of the oil flow path (26) opened to the piton-side space (24) in the inside and the other end of the rod-side space (25) is connected to the inside of the piston rod (8) and then to the head rod ( 2) It is opened to the oil chamber (12) end portion of the pressure accumulating chamber (9) through the inside of the upper end portion.

  The overall hydraulic circuit is as shown in FIG. The hydraulic supply / discharge circuit (27) provided outside has a hydraulic supply path from the hydraulic tank (28) through the hydraulic pump (29) and the hydraulic supply valve (30) to the one oil flow path (21). (31) and a hydraulic discharge path (33) from the flow path (21) through the bypass valve (32) to the hydraulic tank (28), and further, the flow rate of the supply oil is supplied to the flow path (21). A total (34) is connected.

  As shown in FIG. 1, the oil supply / discharge circuit (35) to the accumulator (5) is built near the pressure accumulation chamber (9) inside the head rod (2), as shown in FIG. A counter balance valve (36) and a check valve (37) for opening and closing the flow path (26) are connected in parallel to the oil flow path (26), and an oil flow is connected to the counter balance valve (36). A pilot pressure supply passage (38) for causing the supply oil pressure flowing through the passage (21) to act as a pilot pressure is branched from the oil passage (21) and connected to the counter balance valve (36).

  (39) is a safety relief valve for the oil passage (21), (40) is a check valve for opening the outlet to the outside, and (41) is a safety relief valve for the pressure accumulating chamber (9).

  In FIG. 1, (42) is an excavation head provided at the lower end of the head rod, and (43) is a spiral blade provided on the outer peripheral surface of the head rod, corresponding to the expansion and contraction trajectories of the expansion blades (13) and (13). The part is notched. (44) is a solidifying agent discharge port provided at the lower end of the head rod (2).

  The operation of the above example will be described below together with the enlarged blade holding method using the above example. In the state of FIG. 1 and FIG. 3 (a) in which the tube (6) of the hydraulic cylinder (4) is raised to the maximum position and the expansion blades (13) and (13) are closed, the screw rod (S) and the expansion head (1) is rotated and the excavation head (42) starts excavation of a vertical hole in the ground.

  Enlarged excavation is performed when excavating to a predetermined depth. First, when the expansion blades (13) and (13) are opened to the intermediate expansion opening as shown in FIG. 3B, the expansion blades should be supplied in advance to the cylinder (4) for opening the expansion blade to the intermediate expansion opening. Measure the amount of oil.

  In FIG. 3, the pump (29) of the hydraulic supply / discharge circuit (27) is driven, the supply valve (30) is opened, and the pressure oil passes through the oil passage (21) to the piston side space (24) of the hydraulic cylinder (4). 1), the cylinder tube (6) is lowered, and the lowering of the tube (6) causes the sliding blades (19) and (19) to slide left and right in FIG. The arms (13 ′) and (13 ′) are pushed downward, whereby the expanding blades (13) and (13) start swinging and expanding upward around the pins (15) and (15).

  At the same time, the pressure of the oil flowing through the flow path (21) acts as a pilot pressure on the counter balance valve (36), and when the pressure reaches the set pressure, the valve (36) is opened, and thereby the cylinder (4) The oil in the rod side space (25) is pumped to the oil chamber (12) of the pressure accumulating chamber (9) through the flow path (26) to move the piston (10) rightward, and the air in the air chamber (11) is compressed. It will be done.

  Together with the above operation, the amount of oil supplied until the intermediate expansion is confirmed while looking at the flow meter (34).

  When the intermediate expansion of the expansion blades (13) and (13) is confirmed by the flow meter (34), the supply valve (30) is immediately closed and the oil supply to the cylinder (4) is stopped. The balance valve (36) is also closed, thereby sealing the oil in both the piston side and rod side spaces (24), (25) of the cylinder (4) in an inaccessible manner, and thus the cylinder tube (6) The expansion blades (13) and (13) are securely held at the intermediate expansion position by being restrained to the intermediate lift position.

  By closing the counter balance valve (36), the oil in the oil chamber (12) of the pressure accumulation chamber (9) is also sealed in the pressure accumulation state.

  By rotating the screw rod (S) and the expansion head (1), the intermediate expansion expansion wings (13) and (13) are used to perform the intermediate diameter expansion excavation, and then the supply valve (30) is similarly opened to open the pressure oil. Is further supplied to the piston side space (24) of the cylinder (4) to open the expanding blades (13) and (13) toward the maximum expansion in FIG. Open and send the oil in the rod side space (25) of the cylinder (4) to the oil chamber (12) of the pressure accumulating chamber (9) for further accumulating.

  When the expansion blades (13) and (13) are opened to the maximum expansion opening in FIG. 3 (C), when the supply valve (30) is closed in the same manner as described above, the counter balance valve (36) is also closed and the cylinder (4 ) In the piston side and rod side spaces (24), (25), the expansion blades (13), (13) are held at the maximum opening, and the maximum expansion blade (13) ) And (13), the outer peripheral portion of the intermediate-diameter enlarged excavation hole is further enlarged and excavated, and at the same time, cement milk is discharged from the discharge port (44) into the enlarged excavation hole to form an enlarged bulb of soil cement. .

  An intermediate load excavation or multiple stages of intermediate spread excavation is performed before the maximum spread excavation by the expansion blades (13) and (13), thereby applying an excessive load to the rotational power source of the screw rod (S). Smooth maximum expansion excavation is possible.

  When the expansion blades (13) and (13) are closed after the bulb is formed, the bypass valve (32) of the hydraulic supply / discharge circuit (27) is opened and the oil in the piston side space (24) of the cylinder (4) is discharged. After returning to the tank (28), the screw rod (S) is pulled up and closed by pressing the expanded wings (13) and (13) on the upper part of the bulb and the inner wall surface of the non-expanded vertical hole. The cylinder tube (6) is raised by pressing in the contracting direction, and the oil in the piston side space (24) is returned to the tank (28) through the flow paths (21) and (33).

  At that time, the oil accumulated in the pressure accumulating chamber (9) is returned to the rod side space (25) of the cylinder (4) via the check valve (37), and the pressure of the pressure accumulating oil is reduced in the cylinder tube (6). In cooperation with the ascent, the expansion wings (13) and (13) are given a closing force, and by this closing force, the expansion wings (13) and (13) are easily closed and contracted, whereby the inner wall surface of the vertical hole It will minimize the collapse of the.

  In the above operation, when the pressure in the flow passages (21), (38) becomes abnormally high due to the malfunction of the hydraulic cylinder (4), the relief valve (39) is opened and the check valve is opened. When the pressure in the flow path (26) becomes abnormally high due to the cause of the malfunction of the piston in the pressure accumulating chamber (9), etc., when the oil is discharged from (40) to the outside and the internal pressure is lowered, the relief valve (41) The internal pressure is similarly adjusted by the check valve (40).

It is a vertical front view of the expansion head by this invention. It is an AA line expanded sectional view of FIG. (A) It is a general | schematic line longitudinal cross-sectional view of the hydraulic cylinder of an expansion blade closed state. (B) It is a cross-sectional view of the above-mentioned enlarged wing intermediate expanded state. (C) It is a cross-sectional view of the same and a general hydraulic circuit diagram in the expanded state of the enlarged blade.

DESCRIPTION OF SYMBOLS S Screw rod 1 Expansion head 2 Head rod 4 Hydraulic cylinder 5 Accumulator 9 Pressure accumulation chamber 13 Expansion blade 21 1 system oil flow path 29 Hydraulic pump 30 Hydraulic supply valve 32 Bypass valve 34 Flow meter 36 Counter balance valve

Claims (2)

A hydraulic cylinder is incorporated in the head rod at the lower end of the excavation work rod, and a fluid flow path for supplying and discharging pressure fluid from the outside to the cylinder is vertically passed through the excavation work rod. In the configuration in which the expansion blade is supported to be freely expandable and contractable at the part, and the expansion and contraction of the fluid pressure cylinder and the expansion and contraction of the expansion blade are connected to each other,
A fluid pressure circuit which is disposed outside the at least one fluid flow path and has at least a fluid pressure pump, a pressure fluid supply / discharge valve to the fluid flow path, and a flow meter for the fluid to be supplied;
Either one of the piston-side space and the rod-side space in the fluid pressure cylinder and the one-system fluid flow path are connected so as to freely supply and discharge pressure fluid;
An accumulator is built in the head rod, and a pressure accumulator chamber of the accumulator is connected to the other space in the fluid pressure cylinder,
A counter balance valve having the supplied fluid pressure as a pilot pressure is connected between the other space in the fluid pressure cylinder and the pressure accumulating chamber,
The expansion blade is expanded by supplying a pressure fluid to one space of the fluid pressure cylinder, in which case the fluid in the other space is sent to the pressure accumulating chamber to accumulate pressure,
The pressure fluid supply / discharge valve and the counter balance valve supply the pressure fluid necessary to expand the expansion blade to one space of the fluid pressure cylinder, and the expansion blade expands to a desired expansion opening. The pressure fluid supply / discharge valve and the counter balance valve are immediately closed in such a state that the fluid in both the piston-side and rod-side spaces in the fluid pressure cylinder is confined to hold the expanding blade at the opening degree. And
Fluid pressure cylinder type expansion head with built-in accumulator. A fluid pressure circuit that is disposed outside and has at least a fluid pressure pump, a pressure fluid supply / discharge valve to the fluid passage, and a flow meter for fluid to be supplied is connected to the one system fluid passage, and the fluid The fluid pressure cylinder type expansion head with a built-in accumulator according to claim 1, wherein a counter balance valve using the supplied fluid pressure as a pilot pressure is connected between the other space in the pressure cylinder and the pressure accumulating chamber. use,
The pressure fluid supply / discharge valve is opened, and the flow meter supplies the amount of pressure fluid necessary to expand the expansion blade to a desired expansion opening to one space of the fluid pressure cylinder.
When the expansion blade expands to the desired expansion opening, the pressure fluid supply / discharge valve is immediately closed, and the counter balance valve is also closed accordingly, so that both the piston side and rod side spaces in the fluid pressure cylinder are closed. The above-mentioned expanding blade is held at its opening by confining the fluid of
Expansion wing holding method.

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