JPH10151584A - Impact motion tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an impact motion tool to prevent contact of a valve for controlling hydraulic pressure with an upper wall of a valve chest with an impact and to smoothly carry out lowering change-over of the valve. SOLUTION: First and second plungers 35, 36 to be pushed up by a valve 15 are provided above the valve 15 built in a valve chest 12 of a valve casing 11 free to slide, and a sectional area of the plunger 36 is made larger than a sectional area of the plunger 35. A restrictor 39 is provided in a passage 38 to communicate an upper chamber 37 of the plunger 36 and an oil filler port 25 to each other. At the time when the valve 15 rises near a top dead center and the plunger 36 is pushed up, the valve 15 is decelerated by limiting quantity of oil pushed out of the inside of the upper chamber 37 by the restrictor 39, and contact of the valve 15 with an upper wall of the valve chest 12 with an impact is prevented. Additionally, as it is devised to improve thrust of the plunger by receiving hydraulic pressure of the upper chamber 37 on an upper surface of the plunger 36, speed of the valve at the time of lowering change-over of the valve is increased, and it is possible to smoothly carry out lowering change-over of the valve.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the disassembly of a concrete structure,
The present invention relates to an impact power tool such as a hydraulic breaker used for rock crushing and rock excavation.

[0002]

2. Description of the Related Art An impact power tool which raises a piston by hydraulic pressure, compresses an upper gas when the piston rises, accumulates energy, and lowers the piston by energy due to the expansion of the gas to hit a lower chisel. In Japanese Patent Application Publication No. 7-63939, a valve is incorporated in a valve box and the hydraulic pressure is controlled by raising and lowering the valve so that the piston can be repeatedly moved up and down.

[0003]

By the way, in the impact power tool described in the above publication, as shown in FIG.
The piston 50 rises, and the lower chamber 51 and the actuate chamber 5
When the valve 2 communicates with the valve 2, the pressure oil in the lower chamber 51 flows to the actuating chamber 52 to raise the valve 53. At this time, the large diameter portion 5 of the valve 53
A plunger 56 provided on the valve 53 and the area of the lower end surface of the valve 3a and always supplied with the pressure oil from the oil supply port 55
The valve 53 is raised by the difference from the area of the valve 53, so that the rising speed of the valve 53 is relatively high.
7 may collide with the upper wall 58 of the valve case 5,
In order to prevent the breakage of the mounting bolt 9 and the breakage of the mounting bolt, there is a need for improvement.

When the piston 50 descends and the actuating chamber 52 and the middle chamber 62 communicate with each other during the stroke of the piston 50, pressurized oil is supplied from the oil supply port 55 and the middle chamber 62,
The pressure in the valve chamber 57 increases, and the pressure in the lower chamber 51 communicating through the hole in the center of the valve 53 also increases. This pressure is called the internal charge pressure.

That is, in the stroke of the piston 50,
Since the inside of the valve chamber 57 is pressurized, the plunger 56 can receive only the pressure obtained by subtracting the internal charge pressure from the original pressure (supply oil pressure), and the thrust of the plunger 56 becomes extremely small. Cannot descend quickly.

For this reason, a delay occurs in the timing of the downward switching of the valve 53, and there is still a point to be improved.

SUMMARY OF THE INVENTION It is an object of the present invention to prevent a valve for controlling oil pressure from colliding with an upper wall of a valve chamber during a rising stroke and to smoothly switch a valve down.

[0008]

In order to solve the above-mentioned problems, according to the present invention, a piston is slidably incorporated in a cylinder, and the lower end of the cylinder is provided with the piston when the piston descends. The striking member to be struck is inserted so as to be able to advance and retreat, the piston has a large diameter portion at a middle position, and the cylinder has a middle chamber on the upper surface side of the large diameter portion and a lower chamber on the lower surface side in the cylinder. A chamber is provided, and a valve is slidably incorporated in a valve chamber formed between the lower chamber and the middle chamber and the oil supply port and the oil discharge port, and supply of pressure oil to the lower chamber and the middle chamber by moving the valve up and down. And discharge, and the piston is moved up and down by the pressure of the pressure oil supplied to the lower chamber and the pressure of the gas, and the pressure of the pressure oil supplied to the lower chamber is supplied to the valve during the process of raising the piston. In addition, raise the valve, and above the valve An impact moving tool in which an upper chamber that is always in communication with an oil supply port is provided on a plunger that is sometimes pushed up, and the plunger is lowered by a pressure difference between the upper chamber and a pressure in an upper portion of the valve chamber to push down the valve. A configuration in which one plunger and a second plunger having a larger cross-sectional area than the first plunger are formed, and a throttle is formed in a passage formed on the upper surface side of the second plunger and communicating with the upper chamber and the upper part of the valve chamber. Is adopted.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, a piston 2 is slidably incorporated in a cylinder 1, and a chisel 3 as a striking member is provided below the piston 2. The chisel 3 is movable vertically by a predetermined stroke, and the upper surface is hit by the downward movement of the piston 2.

As shown in FIG. 2, the piston 2 has a large diameter portion 4.
And the upper and lower shaft diameters of the large diameter portion 4 are the same. Inside the cylinder 1, a middle chamber 5 is provided on the upper surface side of the large diameter portion 4.
And a lower chamber 6 is formed on the lower surface side.
As shown in FIG. 1, an upper chamber 7 is provided on the upper surface side.

A gas is sealed in the upper chamber 7. The gas is compressed when the piston 2 rises and energy is stored,
The piston 2 is lowered by the energy due to the expansion of the gas.

A first circumferential groove 8 and a second circumferential groove 9 are provided vertically on the inner diameter surface of the middle chamber 5, while a third circumferential groove 10 is provided above the inner diameter surface of the lower chamber 6. . The second circumferential groove 9 communicates with the first circumferential groove 8 when the piston 2 is at the lowered position,
The large diameter portion 4 blocks the peripheral groove 10. When the piston 2 is in the raised position, the second circumferential groove 9 is in the third circumferential groove 1.
0 and is interrupted by the large diameter portion 4 from the first circumferential groove 8.

As shown in FIG. 2, a valve box 11 is attached to one side of the outer periphery of the cylinder 1. The valve box 11 is a valve room 12
The upper and lower portions of the valve chamber 12 are closed by a top plate 13 and a bottom plate 14.

A valve 15 is slidably incorporated in the valve chamber 12. The valve 15 has a large-diameter portion 16 in the upper portion, and the communication hole 1 penetrating from the upper surface to the lower surface of the large-diameter portion 16.
7 are provided.

On the outer periphery of the valve 15, a first annular groove 18 and a second annular groove 19 are provided vertically. On the other hand, an actuating chamber 20 is provided around the lower part of the large diameter portion 16 of the valve 15 on the inner periphery of the valve chamber 12. The actuating chamber 20 and the second circumferential groove 9 of the cylinder 1 communicate with each other via a trigger port 21.

A fourth peripheral groove 22 and a fifth peripheral groove 23 are provided on the inner periphery of the valve chamber 12 below the actuate chamber 20, and the actuate chamber 20 is provided with a fourth peripheral groove 22 and a pole. It is always in communication with an oil supply port 25 via a small-diameter small-diameter passage 24.

Here, when the valve 15 is at the lowered position, the fourth peripheral groove 22 communicates with the first annular groove 18, and the fifth peripheral groove 23 communicates with the oil supply port 25 via the second annular groove 19. .
Also, when the valve 15 is in the raised position, the fourth circumferential groove 22
Is communicated with the actuating chamber 20 by the first annular groove 18 of the valve 15, the communication of the fifth circumferential groove 23 with the oil supply port 25 is cut off, and the third circumferential groove 10 of the cylinder 1 is connected to the first passage 2.
It communicates with 7. On the other hand, the upper part of the valve chamber 12 and the first circumferential groove 8 of the cylinder 1 communicate with each other through a second passage 28. Also,
The upper part of the valve chamber 12 communicates with the oil discharge port 29 at a position slightly lower than the second passage 28.

A first cylinder chamber 30 is formed in the top plate 13, and a second cylinder chamber 30 is formed on the first cylinder chamber 30.
A cylinder chamber 31 is provided. First cylinder chamber 30
A peripheral groove 32 is formed in the upper part of the inner circumference. The circumferential groove 32 and the annular groove 33 formed on the outer periphery of the top plate 13 communicate with each other through a small-diameter hole 34 extending in the radial direction. The annular groove 33 is always in communication with the oil supply port 25. Here, the flow path diameter of the small diameter hole 34 is set to be somewhat larger than the flow path diameter of the small diameter passage 24.

The first plunger 3 is provided in the first cylinder chamber 30.
5 is freely inserted in the thrust direction, and the circumferential groove 32
Is pressed against the upper surface of the valve 15 by the pressure oil supplied to the valve 15.

The lower end of the second cylinder chamber 31 is connected to the oblique passage 4.
It communicates with the upper part of the valve chamber 12 through 0. A second plunger 36 is slidably inserted into the second cylinder chamber 31. The second plunger 36 has a small diameter portion 41 guided by the first cylinder chamber 30 at a lower end. The cross-sectional area of the upper part of the second plunger 36 is larger than the cross-sectional area of the first plunger 35.

An upper chamber 37 formed at the upper end of the second plunger 36 communicates with the small-diameter hole 34 through a passage 38, and a throttle 39 is provided below the passage 38.

FIG. 1 shows a state where the chisel 3 and the valve 15 are in the lowered position. In this state, the fuel supply port 2 shown in FIG.
When the pressurized oil is supplied to the piston 5, the pressurized oil flows through the fifth circumferential groove 23, the first passage 27, the third circumferential groove 10, and the lower chamber 6, and hydraulic pressure is applied to the lower end surface of the large diameter portion 4 of the piston 2. You.

At this time, since the middle chamber 5 communicates with the first peripheral groove 8, the second passage 28, the upper part of the valve chamber 12, and the oil discharge port 29, the piston 2 is sealed in the upper chamber 7. It starts to rise while compressing the gas (nitrogen gas).

At the same time, the pressure oil from the oil supply port 25 flows into the circumferential groove 32 through the small-diameter hole 34 from the annular groove 33 of the top plate 13 shown in FIG. Therefore, the first plunger 35 and the second plunger 36 are pushed down, and the valve 15 is pushed down by the first plunger 35 and held at the lowered position.

The piston 2 rises and the lower end surface of the large diameter portion 4 rises to the position of the second circumferential groove 9, and as shown in FIG.
When the circumferential groove 9 and the third circumferential groove 10 communicate with each other, the pressure oil in the lower chamber 6 flows to the second circumferential groove 9-the trigger port 21-the actuate chamber 20, and the oil flows into the lower end surface of the large diameter portion 16 of the valve 15. Oil pressure is applied.

Since the area of the lower end face of the large diameter portion 16 is larger than the area of the upper end face of the first plunger 35, the valve 15 moves upward, and the first plunger 35 also moves upward together with the valve 15.

As shown in FIG. 4, when the lower end surface of the valve 15 rises to a position facing the fifth peripheral groove 23, the communication between the supply port 25 and the fifth peripheral groove 23 is blocked by the second annular groove 19. You. The oil outlet 29 is closed by the large diameter portion 16 of the valve 15.

When the valve 15 further rises slightly from the state shown in FIG. 4 and the lower part of the valve chamber 12 communicates with the lower chamber 6 through the first passage 27 as shown in FIG. First passage 27-Fifth circumferential groove 23-Lower part of valve chamber 12-Communication hole 1
7—the upper chamber of the valve chamber 12 —communicates with the middle chamber 5 via the second passage 28, so that the middle chamber 5 and the lower chamber 6 have the same pressure, and the pressure is set to be somewhat lower than the pressure of the fuel supply port 25. Will be retained.

For this reason, the hydraulic pressure acting on the lower end face of the large diameter portion 4 of the piston 2 and the pressure acting on the upper end face become equal,
The piston 2 starts to descend due to the pressure of the compressed gas in the upper chamber 7. When the piston 2 descends, the lower chamber 6
The oil in the lower chamber 6 is pushed down by the large diameter portion 4.
Flows from the communication hole 17 of the valve 15 to the middle chamber 5.

At this time, since the upper and lower shaft diameters of the large-diameter portion 4 of the piston 2 are the same, the volume of the lower chamber 6 is increased by the decrease in the volume of the lower chamber 6, and The pressure of 5 is kept constant, and the lowering of the piston 2 is performed smoothly.

The pressure in the upper and lower portions of the valve chamber 12 is maintained at the same pressure, while the pressure oil is supplied to the actuating chamber 20 from the oil supply port 25 through a very small diameter passage 24. Valve 15 continues to rise.

When the valve 15 is further raised, the first plunger 35 pushes the second plunger 36 up. Second
When the plunger 36 is raised, the oil in the upper chamber 37 is removed from the passage 38.
And flows from the throttle 39 to the small-diameter hole 34 and the annular groove 33, the pressure of the pressure oil in the upper chamber 37 increases, and
Pressure oil acts as a cushion.

Therefore, the valve 15 is decelerated near the top dead center, and the impact of the valve 15 on the top plate 13 is prevented.

FIG. 6 shows a state in which the valve 15 has risen to the position of the top dead center. At this time, when the piston 2 descends, the large diameter portion 4 of the piston 2 closes the second circumferential groove 9 and cuts off the communication between the lower chamber 6 and the actuating chamber 20.
Is supplied from the oil supply port 25 through the oil supply port 25, the valve 15 is held at the position of the top dead center.

When the piston 2 further descends and the upper end surface of the large diameter portion 4 faces the second circumferential groove 9 as shown in FIG.
The trigger port 21 communicates with the middle chamber 5, and the upper and lower portions of the valve chamber 12 communicate with the actuate chamber 20. Then, the pressure oil supplied to the actuating chamber 20 through the small-diameter passage 24 flows from the middle chamber 5 → the upper part of the valve chamber 12 → the communication hole 17 → the lower part of the valve chamber 12 → the lower chamber 6, and the pressure starts to rise. However, the pressure oil from the oil supply port 25 flows in while being throttled in the small-diameter passage 24, so that the pressure is maintained lower than the pressure of the oil supply port 25.

At this time, the upper chamber 3 on the second plunger 36
Since the pressure oil from the oil supply port 25 is always supplied to 7, the pressure in the upper chamber 37 is higher than the pressure in the valve chamber 12, and there is an area difference between the upper surface and the lower surface of the second plunger 36. The second plunger 36 immediately descends and pushes down the first plunger 35 as soon as the trigger port 21 communicates with the middle chamber 5. Further, since the first plunger 35 pushes down the valve 15, the valve 15 starts to descend quickly, the piston 2 descends, and the piston 2 hits the chisel 3, as shown in FIG. Since the pressure in the circumferential groove 32 on the first plunger 35 is higher than the pressure in the actuate chamber 20, the first plunger 35 continues to descend,
By pushing down the first plunger 35, the valve 15 is lowered to the position of the bottom dead center, and returns to the state of FIG.

In the embodiment, the hydraulic breaker is shown as the impact power tool, but the impact power tool is not limited to this.

[0039]

As described above, according to the present invention, when the valve is raised, the second plunger is pushed up via the first plunger, and the oil in the upper chamber formed above the second plunger is restricted from the passage. Since the fluid flows in a continuous manner, the oil in the upper chamber exhibits a function as a hydraulic damper, and the valve rising at a high speed can be decelerated near the top dead center. For this reason, the valve is prevented from colliding with the upper wall of the valve chamber, and the effect of preventing damage to the valve box can be improved.

Further, the plunger for depressing the valve is formed by the first plunger and the second plunger having a larger sectional area than the first plunger, so that the pressure receiving area of the pressure oil supplied from the oil supply port into the upper chamber is increased. Therefore, when the large-diameter portion of the descending piston communicates with the actuating chamber and the middle chamber to switch the valve to the descending motion, the second plunger immediately descends to push down the valve, so that a large initial velocity is given to the valve. The valve can be lowered quickly, and the valve can be smoothly switched to the lower position.

[Brief description of the drawings]

FIG. 1 is a sectional view of an impact power tool according to the present invention.

FIG. 2 is an enlarged cross-sectional view of the valve box of the above.

FIG. 3 is a cross-sectional view showing a state of the above piston during a rising stroke;

FIG. 4 is a sectional view showing a state in which the valve is being lifted.

FIG. 5 is a sectional view showing a state immediately after the start of the lowering of the piston.

FIG. 6 is a sectional view showing an ascending position of the valve of the above.

FIG. 7 is a cross-sectional view showing a state in which the above valve is switched to descend.

FIG. 8 is a sectional view showing a state in which the piston is hit with a chisel.

FIG. 9 is a sectional view showing a conventional impact power tool.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder 2 Piston 3 Chisel 4 Large diameter part 5 Middle room 6 Lower room 7 Upper room 12 Valve room 15 Valve 25 Refueling port 29 Drainage port 35 First plunger 36 Second plunger 37 Upper chamber 38 Passage 39 Throttle

Claims (1)

[Claims] A piston is slidably assembled inside a cylinder, and a striking member struck by the piston is inserted into a lower end portion of the cylinder when the piston descends so as to be able to advance and retreat. Has a large diameter part in the position,
In the cylinder, a middle chamber is provided on the upper surface side of the large diameter portion, and a lower chamber is provided on the lower surface side, and a valve is provided in a valve chamber formed between the lower chamber and the middle chamber and an oil supply port and a drain port. The valve is slidably assembled, and the supply and discharge of pressure oil to the lower chamber and the middle chamber are switched by the vertical movement of the valve, and the piston is moved up and down by the pressure of the pressure oil supplied to the lower chamber and the gas pressure. Let
During the process of raising the piston, the pressure of the pressure oil supplied to the lower chamber is applied to the valve to raise the valve, and an upper chamber that is always in communication with the oil supply port is provided on a plunger that is pushed up when the valve is raised. In an impact power tool in which a plunger is lowered by a pressure difference between an upper chamber and an upper part of a valve chamber to depress a valve, the plunger is composed of a first plunger and a second plunger having a larger sectional area than the first plunger. An impact moving tool, wherein a throttle is formed in a passage formed on the upper surface side of the second plunger and communicating the upper chamber and the upper part of the valve chamber.