JPS5937066A - Impact power tool - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an impact hydraulic power tool such as a concrete breaker.

A piston is slidably provided inside the cylinder, and fluid pressure is alternately supplied to a lower chamber that applies fluid pressure to the lower surface of a large diameter part formed halfway around the outer circumference of the piston, and a royal chamber that corresponds to the upper part of the piston. Note: Move the piston up and down,
Impact hydraulic power tools that hit a chisel placed below when descending usually have a switching valve between the fluid supply passage and the fluid discharge passage, and the fluid supply route is switched by the action of this switching valve. Because I am doing this,
A surge pressure is generated by the switching operation of the valve, and an extremely large impact force is applied to the tool body, and there are disadvantages such as breakage or leakage of the hydraulic rubber hose.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an impact hydraulic power tool capable of eliminating the above two drawbacks and absorbing the surge pressure generated by the switching operation of the switching valve.

The structure of this invention is that a piston for chisel striking is slidably inserted into the cylinder, and a royal part for applying hydraulic pressure is provided on the lower surface of a large diameter part formed in the middle of the outer circle of this piston.
A pressure accumulator filled with high-pressure gas is activated by the hydraulic pressure of the first oil passage connected to this lower chamber, and the surge pressure when the switching valve of the hydraulic pressure supply route is activated is absorbed by the pressure accumulator. It is.

An embodiment of the present invention will be described below with reference to the accompanying drawings.

For convenience of explanation, the left side of FIG. 1 will be referred to as "2" and the right side will be referred to as the bottom.

As shown in FIG. 1, inside the cylinder 1 is a piston 2.
are fitted to be able to move up and down, and a chisel 3 is provided below the piston 2.

In addition, a plug 4 is fitted to the inner upper part of the cylinder 1 to prevent the cylinder head 5 attached to the upper end of the cylinder 1 from being removed, and a small diameter shaft 6 provided at the bottom of the plug 4 is inserted into the piston 2. It is inserted into a hole 7 of a required depth formed in the axial direction from the upper end, and the space formed on one side of the piston 2 is defined as one chamber 8.

An air passage 10 communicates with a vertical hole 9 extending in the axial direction from the child end of the small-diameter shaft portion 6, and the end of the air passage 10 is opened at a part of the outer circumference of the cylinder 1, so that when the piston 2 rises, Air in the holes 7 and vertical holes 9 is discharged to the outside.

The piston 2 has a large diameter portion 11.1 at the upper end and midway of the outer circle.
2, the lower chamber 1 applies hydraulic pressure to the lower surface of the lower large diameter portion 12.
3 is formed inside the cylinder 1. Moreover, on the inside of the cylinder 1, there is a first cylinder between the negative chamber 8 and the lower chamber 13. Second
A circumferential groove 14.15 is provided, and these two circumferential grooves 14.1
5 communicate with each other when the piston 2 is in the lowered position,
When the piston 2 rises, the lower large diameter portion 12 of the piston 2
It is now blocked.

Further, a valve box 16 is provided on a part of the outside +7i1 of the cylinder 1.
is attached to the valve chamber 17 formed inside this valve box 16.
The switching valve 1B is slidably fitted into the valve chamber 17, and the upper part of the pressure rod 19 that is in contact with the upper end of the valve 18 is inserted into the valve chamber 17.
The rod insertion hole 21 is inserted into the rod insertion hole 21 formed in the second end plate 20, and faces the pressurizing chamber 22 communicated with the rod insertion hole 211.

The inner periphery of the valve chamber 17 is provided with a first circumferential groove 23 and a 21st circumferential groove from the top.
'i'6i24,l 3 r#] a25.141m groove 26o, J:.

On the other hand, the switching valve 1B has a first shaft portion 28 corresponding to the inner surface of the protrusion between the first circumferential groove 23 and the second circumferential groove 24, a second fixed groove 24 and a third fixed groove 27. The second shaft portion 29 corresponds to the inner circumferential surface of the protruding portion between the grooves 25 and between the third circumferential groove 25 and the fourth fixed groove 26, and the inner circumferential surface of the protruding portion between the fourth circumferential groove 26 and the fifth circumferential groove 27. Corresponding third shaft portions 3o are formed respectively. With this configuration, when the switching valve 18 is in the lowered position, only the fourth locking groove 26 and the fifth locking groove 27 communicate with each other, and when the switching valve 18 is in the raised position, the third locking groove 26 and the fifth locking groove 27 are in communication with each other.
Only the fixed groove 25 and the fourth fixed groove 26 are made to communicate with each other.

Further, a return passage 31 is formed at the axial center position of the switching valve 18, and a flow rate restricting hole 32 communicating with the lower part of the return passage 31 is opened by an external cause of the third shaft portion 30.

The oil supply passage 33 formed in the valve box 16 communicates with the third fixed groove 25 of the valve chamber 17, and the lower end of the first oil passage 34 formed in the cylinder 1 to communicate with the third circumferential groove 25 communicates with the third circumferential groove 25.
The lower chamber has 13 fleas connected to it.

Further, the first oil passage 34 and the pressurizing chamber 22 in the valve box 16 communicate with each other via a passage 35 and a circumferential groove 36, and
The upper end of the oil passage 34 communicates with an oil chamber 37 provided in the plug body 4.

A pressure accumulation chamber 38 is formed in one side of the oil chamber 37, and a rubber plate 39 stretched over this pressure accumulation chamber 38 is in close contact with the bottom surface of the pressure accumulation chamber 38 due to the pressure I of the gas filled in the pressure accumulation chamber 38. ,
A large number of small holes 40 are formed in the partition wall between the bottom surface and the oil chamber 37.
is formed so that the fluid pressure in the oil chamber 37 acts on the comb plate 39.

The oil chamber 37 and the circumferential groove 14 of the cylinder 1 are connected to the third hole 4.
1, and an operating valve 42 is provided in the middle of the third oil passage 41, and when the operating lever 44 arranged in parallel with the handle 43 of the cylinder head 5 is squeezed, the valve 42 completely opens the third oil passage 41. It is supposed to close.

The third oil passage 41 communicates with the first locking groove 14 of the cylinder 1, and the first locking groove 14 communicates with the first locking groove 23 of the valve body 16, and the first circumferential groove 23 has an oil drain passage 45. It's communicating.

The fourth solid groove 26 of the valve box 16 and the upper chamber 8 of the cylinder 1 communicate with each other via a second channel 46 . Further, the second locking groove 24 of the valve box 16 and the second locking groove 15 of the cylinder 1 communicate with each other via a passage 47.

The impact hydraulic power tool shown in the embodiment has the above-mentioned structure, and this impact hydraulic power tool moves the piston 2 up and down by the hydraulic pressure sent to the oil supply passage 33, and when the piston 2 descends, it strikes the chisel 3 below. This is used to destroy materials to be crushed, such as concrete.

Now, when the operating knob 42 provided in the middle of the third oil passage 41 is in the open state, the oil fed under pressure to the oil supply passage 33 flows from the third circumferential groove 25 to the first oil passage 34, and the oil flows into the first oil passage 34. Road 34
Upward] This flowing hole is the oil chamber 37 - the third hole path 41 - the first fixed groove 14 in the cylinder 1 - the first circumferential groove 2 in the valve box 16
3 and flows out from the drain passage 45, the piston 2
does not move.

Therefore, by operating the operating lever 44, the operating valve 42
When the third oil passage 41 is fully closed, the oil flowing from the oil supply passage 33 to the third circumferential groove 25 and into the first oil passage 34 flows into the lower chamber 12, so that the lower side of the piston 2 Pressure is applied to the lower surface of the large diameter portion 12, causing the piston 2 to move upward.

On the other hand, the oil in the first oil passage 34 flows from the passage 35 and the circumferential groove 36 to the pressurizing chamber 22 and pushes down the pressurizing rod 19, so the switching valve 18 is in a state where it stops below the valve chamber 17 (
The state shown in FIG. 1) is maintained.

By the movement of the piston 2 in one direction, the oil in the upper chamber 8 is pressurized, and this pressurized part is connected from the second passage 46 to the fourth part of the valve body 16.
It flows into the solid groove 26 and the 51st:'d groove 27, further flows through the flow rate restricting hole 32, the return passage 31, and flows from the first solid groove 23 to the drain oil passage 45. Since the drained oil in the upper chamber 8 passes through the throttle hole 32 as described in ``1'', the hydraulic pressure in the upper chamber 8 gradually becomes high, and the upward movement of the piston 2 through this high-pressure hole causes the oil drain passage to flow through the upper chamber 8. 45, the pressure of the oil flowing into the first channel 34 increases, and this pressure acts on the lower surface of the rubber plate 39 through the oil chamber 37 and the small hole 40, and the above pressure is set to the set pressure (accumulation chamber). 38), the rubber plate 39 bends upward and compresses the gas in the pressure accumulating chamber 3B.

When the piston 2 rises and the cylinder lower chamber 13 and the second circumferential groove 15 of the cylinder 1 communicate with each other, the oil in the lower chamber 13 flows into the second circumferential groove 15.
From the circumferential groove 15 and the passage 47 to the second a24 of the valve chamber 17
This flow acts on the lower surface of the first shaft portion 28 of the switching valve 1B. Since this lower surface is larger than the area of the upper end surface of the pressure rod 19, the switching valve 18 moves upward, and the third fixed groove 25 and the fourth fixed groove 26 communicate with each other. (See Figure 2).

By the above fl switching operation of the switching valve 18,
The lower chamber 13 and the upper chamber 8 of the cylinder 1 communicate with each other, and the oil supply passage 33 and the upper chamber 8 communicate with each other, so that hydraulic pressure acts on the second end surface of the piston 2 and the lower surface of the lower large diameter portion 12, and the pressure is roughly accumulated. Room 3
Since the pressure in the oil chamber 37 corresponding to the gas pressure of 8 also acts, the piston 2 rapidly descends and strikes the upper end of the chisel 3 due to the difference in area between the two end surfaces of the piston and the lower surface of the lower large diameter portion 12. do. Therefore, by pressing the lower end of the chisel 3 against the object to be crushed on the concrete road surface, the object to be crushed can be destroyed by the chisel.

Note that when the piston 2 descends, the second locking groove 15 in the cylinder 1 and the drain oil passage 45 communicate with each other, so that the pressure rod 1
The pressure rod 19 and the switching valve 1B are lowered by the oil pressure applied to the upper end surface of the valve 9 to return to the state shown in FIG.
” - The action described above is repeated.

This invention is characterized in that the rubber plate 39 of the pressure accumulation chamber 38 filled with high-pressure gas is deformed under pressure by the hydraulic pressure of the first oil passage 34 that communicates the oil supply passage 33 and the lower cylinder chamber 13. With such a configuration, the first oil passage 34
The surge pressure generated by the switching operation of the switching valve 18 that connects and cuts off the communication and the second ura passage 46 can be absorbed by the gas pressure in the pressure accumulator, reducing the vibration of tools caused by impact pressure, This can prevent damage and leakage. In addition, the oil in the second oil passage that communicates with the upper cylinder chamber flows through the flow restriction hole and into the oil drain passage, so the oil pressure that moves the piston upward ensures that the gas pressure in the pressure accumulation chamber is high. It is possible to apply high pressure to the upper end surface of the piston.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view showing an embodiment of the impact hydraulic power tool according to the present invention, and FIG. 2 is a sectional view showing the same operating state. 1...Cylinder, 2...Piston, 8...Upper chamber, 1
2... Large diameter part, 13... Lower chamber, 18... Switching valve, 32... Throttle hole, 33... Oil supply passage, 34...
・No. 1 Uraji, 38゛°゜pressure accumulation chamber, 39...Rubber plate, 4
5...Oil drain passage, 46...2nd Uraji Patent applicant: Japan Pneumatic Industry Co., Ltd. Agent: Kama 1) Bun 2

Claims (1)

[Claims] In an impact power tool in which a piston for chisel striking is slidably fitted inside a cylinder, the inside of the cylinder has a crown corresponding to the lower surface of a large diameter part provided halfway around the outer circumference of the piston, and an upper end surface of the piston. The piston is connected between a first oil passage communicating with the lower chamber and a second oil passage communicating with the upper chamber, and the oil supply passage and the oil drain passage. When the oil passage rises, the first oil passage, the second oil passage, and the oil supply passage are communicated with each other, and when it descends, the first oil passage and the second oil passage are cut off, and the first oil passage and the oil passage, and A switching valve is provided to communicate the second oil passage and the drain oil passage,
A flow rate restriction hole is formed in the communication part between the discharge passage and the second oil passage, and the hydraulic pressure of the first oil passage communicating with the lower chamber is applied to the lower surface of the rubber plate of the pressure accumulator chamber filled with high-pressure gas. An impact power tool in which a passage is formed between the first oil passage and the lower surface of the rubber plate for operation.