JPH09229007A - Cylinder device of pressure intensified type - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate change of check valve and make compact a cylinder device by forming the hydraulic passage in a booster piston of an axial hydraulic path whose both the ends are closed and a radial hydraulic path crossing the hydraulic path. SOLUTION: Inside a booster piston 5 and pressure intensification parts 6, 7 being integral with the piston 5, a hydraulic passage being the path of working oil is formed. This passage 10 is composed of a hydraulic path 10a extending in the axial direction of the piston 5, hydraulic paths 10b, 10c extending in the circumferential direction from the hydraulic path 10a through circular grooves 14, 15, 16 being communicated by the position of piston 5. The changeover to the operation direction in the piston 5 is carried out through the hydraulic passage 10 and the circular grooves 14, 15, 16. In passages being communicated with a main cylinder from pressure intensifying chambers 8, 9 and passages being communicated with an automatic changeover valve, check valves 26, 27, 30, 32 for preventing generation of reverse flow are arranged respectively so that they can be mounted and demounted on/from a cylinder block 11 freely for easy replacement.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure increasing type cylinder device used for crushing concrete at a construction site and driving a hydraulic cutter for steel frames and reinforcing bars.

[0002]

2. Description of the Related Art As shown in Japanese Patent Application Laid-Open No. 62-297508, a conventional pressure-increasing cylinder device includes a cylinder body for driving an attachment such as a crusher, and a pressure-increasing cylinder for supplying high-pressure hydraulic oil to the cylinder body. The booster piston that reciprocates inside the boosting cylinder forms pressure boosting chambers at both ends of the boosting cylinder. High-pressure hydraulic oil is supplied to the cylinder body from the booster chamber to crush concrete.

[0003]

However, in the above-described conventional booster type cylinder, the check valve for controlling the direction of the flow of the hydraulic oil in the booster cylinder is incorporated in the booster piston integrally with the booster piston. Therefore, if the check valve breaks down due to dust mixed in the hydraulic oil, the booster piston must be disassembled and repaired each time, which requires a lot of time and labor. Since the check valve requires precision because of its structure, it must be replaced after a certain amount of use.In that case, the check valve is integrated with the booster piston, so an expensive booster piston is also included. Had to be replaced with an extra cost.

Further, since the circular groove for detecting the position of the booster piston is formed on the booster piston side, a certain interval between the circular grooves is required to reliably switch the operating direction of the booster piston, so the booster piston must have a certain distance. There is also a problem that the piston also requires a length, which makes the entire device large and cannot be downsized. The present invention has been made in view of the above-mentioned conventional problems, and provides a pressure-increasing cylinder device in which the check valve can be easily replaced, and the size and weight can be reduced.

[0005]

In order to achieve the above object, the present invention provides a booster cylinder having a large diameter booster piston chamber in its central portion and small diameter booster chambers provided on both sides of the booster piston chamber. A cylinder block in which the booster cylinder is incorporated through a sleeve; a booster piston that has a central portion formed to have a large diameter and has an oil passage inside; and a reciprocating motion in the booster cylinder; and a booster chamber of the booster cylinder. A plurality of check valves provided in the middle of an oil passage connected to the oil tank, an automatic switching operation valve that alternately switches a hydraulic pressure supply port and an oil discharge port from an oil tank by a hydraulic pump, the automatic switching operation valve and the booster piston chamber. Connecting a plurality of oil passages, a circular groove formed in the booster cylinder, and a booster piston by the circular groove and the booster piston position. And a position detecting means for detecting the position of the booster piston, and the booster piston is reciprocated to supply a high hydraulic pressure from a booster chamber of the booster cylinder. It is formed of an axial oil passage formed in the axial direction of the piston and closed at both ends, and a circumferential oil passage intersecting with the axial oil passage and extending in the circumferential direction. It is a feature. Further, the check valve is detachably attached to the cylinder block. The circular groove is formed in the sleeve of the booster cylinder.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. 1 is a cross-sectional view schematically showing a booster type cylinder device of the present invention, FIG. 2 is an enlarged view of a main part of the booster type cylinder device of FIG. 1, and FIG. 3 is a block diagram of the booster type cylinder device of FIG. It is the figure which represented the state attached to the attachment typically.

As shown in FIG. 3, the booster type cylinder device A of the present invention is attached to a cylinder body B for operating an attachment D such as a concrete crusher. , A switching valve device C for controlling the booster cylinder device A
Is attached. In these devices, a main piston 2 is loosely fitted inside a main cylinder 1 in a cylinder body B, and a piston rod 2a integrated with the main piston 2 penetrates a front portion of the cylinder 1 and projects forward. The tip of the piston rod 2a is attached to the movable blade E of the attachment D, and hydraulic oil is sent from the oil tank T on the dolly side by the hydraulic pump P to operate the movable blade E.

As shown in FIG. 1, the booster type cylinder device A has a booster cylinder 3 having a large-diameter booster piston chamber 4 inside and small-diameter booster chambers 8 and 9 formed on both sides thereof.
The sleeve 13 surrounding the booster cylinder 3 is incorporated in the cylinder block 11 in which an oil passage communicating with the booster cylinder 3 is formed, so that the booster piston 5 having a large diameter reciprocates in the booster piston chamber 4. Is configured. Further, on both sides of the booster piston 5, a small diameter left pressure increasing portion 6 and a right diameter pressure increasing portion 7 are formed integrally with the booster piston 5, and these small diameter pressure increasing portions 6, 7 are formed.
Is configured to reciprocate in a small diameter left pressure increasing chamber 8 and a right diameter pressure increasing chamber 9 which communicate with both sides of the booster piston chamber 4.

Further, inside the booster piston 5 and the pressure increasing portions 6 and 7 which are integral with the booster piston 5, an oil passage 10 which serves as a passage for operating oil is formed. The oil passage 10 includes an oil passage 10a extending in the axial direction of the booster piston 5 and circular grooves 14 and 1 to be described later depending on the position of the booster piston 5.
5 and 16 communicate with each other, and are constituted by oil passages 10b and 10c formed in the circumferential direction from the oil passage 10a.
The operation of the booster piston 5 is switched by the action of the oil passage 10 and the circular grooves 14, 15, 16 as described later. Further, since it is not necessary to communicate the oil passage 10a with the pressure increasing chambers 8 and 9 for discharging the hydraulic oil in the booster piston chamber 4, both ends of the oil passage 10a are closed, and therefore, conventionally, the oil passage 10a is provided in the oil passage 10a. The structure is such that the two check valves for preventing backflow from the pressure increasing chambers 8 and 9 side that have been provided are unnecessary.

Further, from the pressure increasing chambers 8 and 9 to the main cylinder 1
Oil passages 24 and 25 leading to the air and an automatic switching valve 20 described later.
Check valves 26, 27, 30 and 32 for preventing backflow are attached to the oil passages 29 and 31 communicating with each other. Since the check valves 26, 27, 30, 32 have the same structure, the check valve 32 will be described.
As shown in FIG. 2, the check valve 32 is attached to the end surface of the cylinder block 11, is inserted into the attachment hole from the right side of the drawing, and is attached to the plate 12 so as to be urged by the plate 12. Fixed. Also, when removing, it can be taken out by removing the plate 12. Since no special screws or the like are used to fix the check valve 32, the check valve 32 can be easily attached and detached. The internal structure of the check valve 32 is such that the plunger 32a is biased by the spring 32b.
Although the hydraulic oil to the side can pass therethrough, the flow of the hydraulic oil from the pressure increasing chamber 9 side to the oil passage 31 is blocked.

Further, the booster piston chamber 4, the pressure increasing chamber 8,
The periphery of the booster cylinder 3 made of 9 is surrounded by a sleeve 13. Sleeve 1 at the position of the left booster chamber 8
3a has two narrow circumferential grooves 14 and 15 formed at intervals of the stroke of the booster piston 5, and the position sleeve 13b of the pressure boosting chamber 9 on the right side has a circular groove 16 having a wide stroke of the stroke of the booster piston 5. Are formed. These circular grooves 14, 15, 16 are respectively provided with oil passages 17, 18,
19 is connected, the oil passage 17 is connected to the hydraulic pump P via the switching operation valve, and the oil passage 18 is connected to the oil passage 21 of the spring return type automatic switching valve 20 operated by hydraulic operation. The oil passage 19 is connected to the automatic switching valve 20, and the automatic switching valve 20 is operated by the hydraulic oil flowing into the oil passage 19.

Further, oil passages 22 and 23 for supplying and discharging hydraulic oil from the automatic switching valve 20 are connected to the left and right ends of the booster piston chamber 4, and the pressure increasing chambers 8 and 9 are
Oil passages 24, 25 for supplying high-pressure hydraulic oil to the main cylinder 1 are connected. Check valves 26 and 27 are provided between the oil passages 24 and 25 and the main cylinder 1 to prevent the hydraulic oil from flowing back from the main cylinder 1 to the pressure increasing chambers 8 and 9. Similarly, a check valve 30 for preventing backflow is attached to the oil passage 29 between the pressure boosting chamber 8 and the automatic switching valve 20, and the pressure boosting chamber 9 and the automatic switching valve 2 are attached.
A check valve 32 for preventing backflow is attached to the oil passage 31 between 0.

Next, the operation of the above-described booster type cylinder device A will be described with reference to FIGS. 4, 5 and 6. First, FIG.
Is a hydraulic circuit diagram showing a cylinder rising process, in which a hydraulic oil is supplied from an oil tank T on the dolly side through a switching valve device C by a hydraulic pump P, and a pilot check for preventing backflow is provided midway in an oil passage 33. The valve 34 is opened to flow into the piston chamber 1a of the cylinder body 1. Then, since the piston 2 is pushed to the right, the hydraulic oil in the piston rod chamber 1b is pushed out by the piston 2, passes through the oil passage 35, the switching valve device C, and returns to the oil tank T.

Thus, the piston 2 becomes the piston rod 2a.
It moves to the right with it, but if a load is applied to the piston rod 2a in the middle, the movement of the piston 2 stops, so the pressure of the hydraulic oil flowing into the piston chamber 1a rises and reaches the set pressure of the sequence valve 36. . Then, the sequence valve 36 is opened, and the hydraulic oil passes through the automatic switching valve 20,
It flows into the right chamber 4b of the booster piston chamber 4 through the oil passage 23 and pushes the booster piston 5 to the left.

At this time, the hydraulic pressure of the piston chamber 1a of the main cylinder 1 is also applied to the check valves 26 and 27,
The pressure boosting chambers 8 and 9 are also filled with hydraulic oil, but since the diameter of the pressure boosting portion 6 is smaller than the diameter of the booster piston 5, the booster piston 5 pushes the hydraulic pressure of the pressure boosting chamber 8 into the main pressure. The hydraulic pressure becomes higher than that of the piston chamber 1a of the cylinder 1, and the check valve 26 is pushed open to allow high-pressure hydraulic oil to flow into the piston chamber 1a.

In this way, when the booster piston 5 moves to the left, the oil passage 10 in the booster piston 5 also moves, so that when the left oil passage 10b reaches the position of the circumferential groove 14, the hydraulic oil is supplied from the oil passage 17. Flows into the oil passage 10b, and further, this hydraulic oil flows into the oil passage 19 from the circular groove 16 via the oil passages 10a and 10c in the booster piston 5, and switches the automatic switching valve 20.

Then, this time, as shown in FIG. 5, the hydraulic oil passes through the automatic switching valve 20, passes through the oil passage 22 and flows into the left chamber 4a of the booster piston chamber 4, and the booster piston 5
Start pushing to the right. As a result, the booster piston chamber 4
The hydraulic oil in the right chamber 4b of the vehicle is pushed out, enters the oil passage 21 through the automatic switching valve 20 via the oil passage 23, opens the check valve 37 provided in the oil passage 21 and enters the oil passage 35. , Return to the oil tank T via the switching valve device C. Further, when the booster piston 5 moves to the right in this way, the pressure increasing portion 7 integrated with the booster piston 5 pressurizes the hydraulic oil in the pressure increasing chamber 9 while pushing the check valve 27 open to feed the piston chamber 1a. .

When the booster piston 5 moves to the right, the oil passage 10 inside the booster piston 5 also moves, but initially the oil passage 10b is not located at the week groove 15, so the oil passage 18 is blocked. , The automatic switching valve 20 is held in the previous state. When the booster piston 5 moves further to the right, the oil passage 10b in the booster piston 5 reaches the position of the circular groove 15, so the oil passage 18 and the oil passage 10 in the booster piston 5 and the oil passage 19 from the circular groove 16. Is connected to the low pressure circuit, the pilot valve of the automatic switching valve 20 is opened, so that the automatic switching valve 20 is switched by the spring force. Then, since it returns to the initial state, the hydraulic oil again flows into the right chamber 4b of the booster piston chamber 4 through the oil passage 23,
The first operation of pushing the booster piston 5 to the left is repeated.

By repeating the above operation, the booster piston 5 reciprocates, so that high-pressure hydraulic oil is alternately pushed out from the pressure increasing chambers 8 and 9 on the left and right of the booster piston chamber 4 to cause the main cylinder 1 to move. Since the hydraulic pressure in the piston chamber 1a is increased, the piston 2 is pushed by a great force and can perform work such as crushing of concrete lumps by a crusher or the like. When the work is completed, as shown in FIG. 6, the switching valve device C is switched and the rod chamber 1b of the main cylinder 1 is routed from the oil tank T via the oil passage 35.
Into the tank. Therefore, hydraulic pressure is generated in the pilot circuit 38 and the pilot check valve 34 opens. Then, the working oil returns from the piston chamber 1a of the main cylinder 1 to the oil tank T via the oil passage 33. Then, due to the oil pressure in the rod chamber 1b, the main piston 2 moves leftward and returns to the initial state. Also, after this work is completed, the switching valve device C is returned to the initial position and completed.

[0020]

According to the present invention, a booster cylinder having a large-diameter booster piston chamber in its central portion and a small-diameter booster chamber provided on both sides of the booster piston chamber, and the booster cylinder are assembled through a sleeve. Cylinder block,
A booster piston having a central portion formed to have a large diameter and having an oil passage therein and reciprocating in the booster cylinder, and a plurality of check valves provided in the middle of the oil passage connected to the booster chamber of the booster cylinder, An automatic switching valve that alternately switches a hydraulic pressure supply port and an oil discharge port from an oil tank by a hydraulic pump, a plurality of oil passages that connect the automatic switching valve and the cylinder chamber, and a circular groove formed in the booster cylinder, A pressure-increasing cylinder in which position detection means for detecting a booster piston position by the circular groove and the booster piston position is provided, and high-pressure oil pressure is supplied from a pressure-increasing chamber of the booster cylinder by reciprocating motion of the booster piston, The oil passage in the booster piston is
An axial oil passage formed in the axial direction of the booster piston and having both ends closed, and a circumferential oil passage intersecting with the axial oil passage and extending in the circumferential direction are formed. Since the check valve is detachably attached to the cylinder block, the plurality of check valves attached to the booster cylinder can be easily removed, so that the labor for disassembling the booster piston can be saved and the repair cost can be reduced. be able to. In addition, since the circular groove is formed in the sleeve of the booster cylinder, the booster piston can be downsized, so that the booster type cylinder device as a whole can be downsized and lightened. It can also be mounted on lightweight construction machinery.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing a booster type cylinder device of the present invention.

FIG. 2 is an enlarged view of a main part of the booster type cylinder device of FIG.

FIG. 3 is a state diagram in which the booster type cylinder device of FIG. 1 is attached to an attachment.

FIG. 4 is a hydraulic circuit diagram showing the operation of the pressure boosting cylinder device of FIG.

5 is a hydraulic circuit diagram showing an operation of the pressure boosting cylinder device of FIG. 1. FIG.

FIG. 6 is a hydraulic circuit diagram showing the operation of the booster type cylinder device of FIG. 1.

[Explanation of symbols]

 A booster type cylinder device B cylinder body C switching valve device D attachment P hydraulic pump T oil tank 1 main cylinder 1a piston chamber 1b piston rod chamber 2 main piston 2a piston rod 3 booster cylinder 4 booster piston chamber 5 booster piston 6 booster unit 7 Pressure Booster 8 Pressure Booster Chamber 9 Pressure Booster Chamber 10 Oil Path 11 Cylinder Block 12 Plate 13 Sleeve 14 Circular Groove 15 Circular Groove 16 Circular Groove 17 Oil Pass 18 Oil Pass 19 Oil Pass 20 Automatic Switching Valve 21 Oil Pass 22 Oil Pass 23 oil passage 24 oil passage 25 oil passage 26 check valve 27 check valve 29 oil passage 30 check valve 31 oil passage 32 check valve 33 oil passage 34 pilot check valve 35 oil passage 36 sequence valve 37 check valve 38 pilot circuit

Claims (3)

[Claims] 1. A booster cylinder having a large-diameter booster piston chamber in the center thereof, and small-diameter booster chambers provided on both sides of the booster piston chamber; and a cylinder block in which the booster cylinder is incorporated through a sleeve. A booster piston that has a large diameter in the center and has an oil passage inside and reciprocates in the booster cylinder; and a plurality of check valves provided in the middle of the oil passage connected to the booster chamber of the booster cylinder. An automatic switching valve that alternately switches a hydraulic pressure supply port and an oil discharge port from an oil tank by a hydraulic pump; a plurality of oil passages connecting the automatic switching valve and the booster piston chamber; and a circular groove formed in the booster cylinder. And position detecting means for detecting the booster piston position by the circular groove and the booster piston position. In a booster cylinder in which a high pressure oil is supplied from the booster chamber of the booster cylinder by the reciprocating motion of a ton, the oil passage in the booster piston is formed in the axial direction of the booster piston, and the both ends are closed in the axial direction. Oil passage,
And a circumferential oil passage extending in the circumferential direction so as to intersect with the axial oil passage. 2. The pressure-intensifying type cylinder device according to claim 1, wherein the check valve is detachably attached to the cylinder block. 3. The booster type cylinder device according to claim 1, wherein the circular groove is formed in a sleeve of a booster cylinder.