JP3168365B2 - Three-stage hydraulic jack - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-stage hydraulic jack used for a main pushing device for a pipe propulsion method.

[0002]

2. Description of the Related Art Conventionally, in a propulsion method, a main pushing speed is required in accordance with a digging speed of a shield excavator at a leading portion. As a means for achieving constant-speed elongation, (a) each stage of a cylinder is required. Method of pumping the amount of hydraulic oil separately (b)
Various means have been adopted, such as a method in which necessary hydraulic oil is sealed in advance in each stage of the cylinder, and a method (c) in which the pressure receiving areas of the pistons in each stage are made equal.

[0003]

However, the above (a)
In order to separately pump the required amount of hydraulic oil to each stage of the cylinder, a hydraulic oil feeder with a complicated structure must be specially installed in addition to the cylinder device. In order to keep the hydraulic oil sealed, it is necessary to always check the leakage of the sealed hydraulic oil for each of the three stages. Further, in order to make the pressure receiving area of each stage (c) equal, for example, When the central hollow guide 1b is provided as in Japanese Utility Model Publication No. 2-28252, the outer diameter of the cylinder becomes larger than the pushing ability of the piston.
In the case of No. 4, there is a disadvantage that the maximum outer diameter portion moves, which causes inconvenience such as contact with an operator or another device.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a cylindrical outer cylinder 1;
a first-stage cylinder 1 having a first-stage cylinder chamber P formed concentrically with an inner cylinder 1b inside the first cylinder 1a, and a first-stage cylinder chamber P between the outer cylinder 1a and the inner cylinder 1b; The first-stage piston portion 2a and the first-stage piston rod 2b are formed in a double cylindrical shape by a rod 2b, an outer cylinder cylinder Q, and an inner cylinder 2c inside the second cylinder chamber R. A first-stage piston 2 in which an inner cylinder 2c is slidably mounted in an inner cylinder 1b into a cylinder chamber P of the first-stage cylinder 1; together with a second-stage piston portion 3a and a second-stage piston rod 3b, A second-stage piston 3 formed in a double cylindrical shape from the inner cylinder 3c forming the third-stage cylinder chamber S and slidably mounted in the second-stage cylinder chamber R;
a, a third-stage piston rod 4b, and a third-stage piston 4 slidably mounted in the third cylinder chamber S; closing the front opening of the cylindrical third-stage piston rod 4b, A plug body 5 forming an oil chamber T in an inner space of the rod 4b; a front chamber Pa of the first-stage cylinder chamber P, a cylinder chamber Q inside the first-stage piston rod 2b when the respective pistons are pushed out, The front chamber Ra of the second-stage cylinder chamber R, the oil chamber T inside the third-stage piston rod 4b, and the third-stage cylinder chamber S
Oil passage 6a and oil passages 6b, 7a, 7b for supplying hydraulic oil to the front chamber Sa of the first stage; the rear chamber Pb of the first stage cylinder chamber P and the second stage cylinder chamber R at the time of each piston pushing operation.
And the oil passage 8b and oil passages 8b, 9a, 9b for discharging hydraulic oil from the rear chamber Rb and the rear chamber Sb of the third-stage cylinder chamber S, and the pressure receiving area of the first-stage piston portion 2a (that is,
Area A of the first-stage cylinder chamber P) and the first piston rod 2
b, the sum of the pressure receiving areas B of the cylinder chambers Q, the outer diameter cross-sectional area C of the cylindrical second-stage piston portion 3a, the pressure receiving area D of the third-stage piston portion 4a, and the inner diameter of the cylindrical third-stage piston rod 4b. The basic configuration of the present invention is to maintain the relationship of A + B = C = D + E with the sectional area E.

[0005]

When the piston rods 2b, 3b, 4b are to be pushed out, hydraulic fluid is supplied directly from the flow oil port 6a to the front chamber Pa of the first cylinder chamber P, and the cylinder chamber Q
From the gap oil passage between the inner cylinder 1b and the first stage piston portion 2a,
From the oil passage 6b to the front chamber Rb of the second-stage cylinder chamber R,
The oil is supplied from the oil passage 7a to the front chamber Sa of the stage cylinder chamber S, and is supplied from the oil passage 7b to the oil chamber T.

The sum of the pressure receiving area A in the first-stage cylinder chamber P and the pressure-receiving area B of the cylinder chamber Q formed in the first-stage piston rod 2b and the inner cylinder 2c, and the outer-diameter cross-sectional area C of the second-stage piston portion 3a , The pressure receiving area D of the third stage piston portion 4a and the third
The sum of the inner diameter cross-sectional area E of the step piston rod 4b is A
+ B = C = D + E is maintained, and as a result, the extension speed V of the piston in each stage is V1 = U in the first stage piston when the pressure oil discharge amount of the hydraulic pump (not shown) is U.
/ (A + B), V2 = U / C for the second stage piston, 3rd stage
In the stage piston, V3 = U / (D + E). Here, since A + B = C = D + E, V1 = V2 = V3, and it is apparent that the piston is extended to the left at a constant speed.

On the other hand, each extended piston rod 2b,
3b and 4b, return the oil passage 8a to the oil passage 8a.
b, 9a, and 9b, the hydraulic oil is fed.

[0008]

FIG. 1 is a front view of a propulsion device provided with a three-stage extending hydraulic jack, FIG. 2 is a sectional view showing a contracted state of a three-stage extended hydraulic jack of the present invention, and FIG.

In FIG. 1, a first-stage cylinder 1 is formed of an inner cylinder 1b provided concentrically with an outer cylinder 1a having an open left side, and a first-stage cylinder chamber P (cylinder front chamber Pa,
The first stage piston 2 inserted into the cylinder chamber P is divided into a cylinder front chamber Pa and a cylinder rear chamber Pb. An inner cylinder 2c concentric with the piston rod 2b of the first stage piston 2 forms a cylinder chamber Q to receive the inner cylinder 1b of the first cylinder 1, and the first cylinder 1 and the first stage piston 2 are slidable. Inner cylinder 1 which is inserted into
Except for the outer wall of b, oil tightness is maintained by packing (no number). The first stage piston 2
Inner cylinder 2c forms a cylinder of a second-stage piston 3 described later.

The second stage piston 3 includes a piston rod 3
b and the inner cylinder 3c are formed in a double cylinder shape, and the base ends of the inner and outer cylinders are a second-stage piston portion 3a and a second-stage piston rod 3b. A third cylinder chamber S is provided between the two-piston rod 3b and the inner cylinder 3c, into which a third-stage piston 4 described later is inserted. Further, an oil passage 7b passes through the inner cylinder 3c. I have.

The second-stage piston portion 3a is provided with oil through a packing into a second-stage cylinder chamber R (a cylinder front chamber Ra and a cylinder rear chamber Rb) formed by the inner cylinder 2c of the first stage piston 2. The piston rod 3b is densely slidably inserted, and the piston rod 3b is slidably supported at the distal end opening of the first stage piston 2 via packing.

The piston rod 3b of the second-stage piston 3 forms the cylinder of the third-stage piston 4 as described above.
A third-stage piston portion 4a described later is slidably inserted therein. The third-stage piston 4 is formed of a cylindrical third-stage piston rod 4b and a donut-shaped third-stage piston portion 4a, and is provided between the outer cylinder 3b and the inner cylinder 3c of the second-stage piston 3. It is slidably inserted into the formed third-stage cylinder chamber S (cylinder front chamber Sa, cylinder rear chamber Sb) via packing.

The piston rod 4b of the third-stage piston 4 is slidably supported at the opening on the distal end side of the second-stage piston 3 via packing. Further, the left side opening of the cylindrical piston rod 4b of the third stage piston 4 is closed by a plug 5, and an oil chamber T is formed therein. In addition, 6a, 8a is a flow port, 6b, 8b, 7a, 7
b, 9a and 9b are oil passages.

To extend and retract each of the pistons 2, 3, and 4,
Pressure oil is sent from a hydraulic oil port 6a or 8a from a hydraulic pump (not shown), and discharged from a hydraulic oil passage 8a or 6a, respectively. That is, at the time of extension, the pressurized oil that has entered the front chamber Pa of the first-stage cylinder chamber P from the oil flow port 6a presses the first-stage piston portion 2a, and simultaneously presses the outer wall of the cylindrical cylinder wall 1b with the first-stage piston portion. From the gap oil passage on the inner wall of 2a, the first stage piston 2 is moved to the left by entering the cylinder chamber Q formed by the inner wall of the first stage piston rod 2b and the outer wall of the inner cylinder 2c, and further from the cylinder chamber Q 6b, enters the front chamber Ra of the second-stage cylinder chamber R, presses the piston portion 3a of the second-stage piston 3 to extend the second-stage piston 3, and then moves from the oil passage 7a to the third cylinder chamber S. The pressure oil that has entered the piston portion 4a of the fourth stage piston 4 and the pressure oil that has entered the oil chamber T from the oil passage 7b presses the plug 5 to move the fourth stage piston 4 to the left.

At the time of contraction, the pressure oil which has entered the rear chamber Pb of the first cylinder chamber P from the flow oil port 8a is applied to the left side surface of the piston portion 2a of the first stage piston 2 through the oil passage 8b to the second cylinder chamber R.
b enters the piston portion 3a of the second stage piston 3.
Of the third cylinder chamber S in the oil passage 9a presses the left side surface of the piston portion 4a of the fourth stage piston 4 rightward, and the piston of each stage Shrink the rod.

[0016]

According to the present invention, the overall length of the main pushing device is shortened, the outer diameter of the cylinder is made compact, and an oil supply pipe or valve externally mounted as in Japanese Utility Model 2-28252 is not required. Intermediate guide 5 like 99894
(A jack stand and a moving slide) is not required, so that a large work space can be taken, the jack arrangement becomes easy, and the safety is dramatically improved.

[Brief description of the drawings]

FIG. 1 is a front view of the propulsion device. FIG. 2 is a contracted view of the three-stage hydraulic jack. FIG. 3 is a cross-sectional view in a state where the stretching is performed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 1st stage cylinder 2 1st stage piston 3 2nd stage piston 4 3rd stage piston 5 Plug 1a Cylindrical outer cylinder 1b Inner cylinder 2a 1st stage piston part 2b 1st stage piston rod 2c Inner cylinder 3a 2nd stage Piston part 3b Second stage piston rod 3c Inner cylinder 4a Third stage piston part 4b Third stage piston rod 6a Flow oil port 6b Flow oil port 7a Oil path 7b Oil path 8a Flow oil path 8b Flow oil port 9a Oil path 9b Oil Road A Pressure receiving area B Pressure receiving area C Outer diameter cross-sectional area D Outer pressure cross-sectional area E Inner diameter cross-sectional area P First-stage cylinder chamber Pa Front chamber Pb Rear chamber Q Cylinder chamber R Second-stage cylinder chamber Ra Front chamber Rb Rear chamber S Third stage Cylinder chamber Sa Front chamber Sb Rear chamber

Claims (1)

(57) [Claims] 1. A three-stage hydraulic jack, wherein an inner cylinder 1b is formed concentrically inside a cylindrical outer cylinder 1a, and a first-stage cylinder chamber P is provided between the outer cylinder 1a and the inner cylinder 1b. The stage cylinder 1; a first stage piston portion 2a and a first stage piston rod 2b, and a double cylinder formed from a cylinder chamber Q on the outside and an inner cylinder 2c on the inside forming a second cylinder chamber R. And the first-stage piston portion 2a and the first-stage piston rod 2
b into the cylinder chamber P of the first stage cylinder 1 and the inner cylinder 2
1st stage piston 2 slidably mounted in inner cylinder 1b
And the second-stage piston portion 3a and the second-stage piston rod 3
b, a second-stage piston 3 formed in a double cylindrical shape from an inner cylinder 3c forming a third-stage cylinder chamber S, and slidably mounted in the second-stage cylinder chamber R; A portion 4a, a third-stage piston rod 4b, and a third-stage piston 4 slidably mounted in the third cylinder chamber S;
A plug 5 for closing a front opening of the cylindrical third-stage piston rod 4b and forming an oil chamber T in an inner space of the piston rod 4b; and the first-stage cylinder chamber P when each piston is pushed out. , The cylinder chamber Q of the first-stage piston rod 2b, the front chamber Ra of the second-stage cylinder chamber R, the oil chamber T inside the third-stage piston rod 4b, and the third-stage cylinder chamber S
And an oil passage 6a for supplying hydraulic oil to the front chamber Sa, and oil passages 6b, 7a, 7b. The rear chamber Pb and the second cylinder chamber R of the first-stage cylinder chamber P at the time of each piston pushing operation. An oil outlet 8a for discharging hydraulic oil from the rear chamber Rb and the rear chamber Sb of the third-stage cylinder chamber S, and oil passages 8b, 9a, 9
b and the pressure receiving area A of the first stage piston portion 2a.
And the pressure receiving area B of the cylinder chamber Q of the first piston rod 2b
, The outer diameter cross-sectional area (pressure receiving area) C of the cylindrical second stage piston portion 3a, the sum of the pressure receiving area D of the third stage piston portion 4a and the inner diameter cross sectional area E of the cylindrical third stage piston rod 4b. Characterized in that a relationship of A + B = C = D + E is maintained between the hydraulic jack and the hydraulic jack.