JPS63110389A - Gas type hydraulic impact tool - Google Patents

Abstract

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

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a gas-powered hydraulic impact tool.

(Prior art) As an example of a striking tool, a piston that moves back and forth by hydraulic pressure is provided in the cylinder body, and a gas chamber filled with compressed gas is provided behind the piston, so that the repulsion of the compressed gas compressed when the piston retreats is provided. 2. Description of the Related Art Gas-type hydraulic impact tools are generally known that use force to urge a piston to move forward and strike a tool body such as a chisel. For example, Japanese Patent Publication No. 49-29801 discloses that in such a gas-type hydraulic impact tool, when the piston retreats, the oil supplied to the cylinder body is rapidly discharged to increase the forward speed of the piston. There is a description of a technique for preventing cavitation in the discharge pipe by preventing it from accelerating.

(J?! Akira is trying to solve the problem) In the gas-powered hydraulic impact tool mentioned above, the compressed gas in the gas chamber is sealed at a set pressure suitable for impacting the tool body, but due to changes in the outside temperature, As the compressed gas expands and contracts, the sealing pressure in the gas chamber changes, causing problems such as changing the impact force or causing malfunction.

(Means for Solving the Problems) As a means for solving the above-mentioned problems, the present invention provides a cylinder body with a first port communicating with the gas chamber, a second port for opening to the atmosphere, and a compression port from the gas chamber. A valve chamber is formed with a third port to which gas having a higher pressure than the gas is supplied, and the valve chamber includes a valve member that receives the pressure of the compressed gas from the first port at one end, and this valve member as described above. A biasing means for biasing the compressed gas in a direction opposite to the pressure receiving direction is provided, and the movement of the valve member in the pressure receiving direction connects the first and second ports, and the movement in the opposite direction causes the first and second ports to communicate with each other. The present invention provides a gas-type hydraulic impact tool in which the first and third ports are communicated with each other.

(Function) In the case of the above-mentioned gas-type hydraulic impact tool, when the pressure in the gas chamber decreases, the valve member moves in the opposite direction to the pressure receiving direction due to the urging of the urging means, and the valve member moves in the opposite direction to the pressure receiving direction, and the valve member moves in the opposite direction to the pressure receiving direction. are in communication, and high pressure gas is supplied from the third port to the gas chamber via the first port. As the pressure in the gas chamber increases, the valve member moves in the pressure receiving direction to a position where the pressure from the gas chamber side and the urging force of the urging means are balanced, and communication between the first port and the third port is cut off. dripping On the other hand, when the pressure in the gas chamber increases,
The valve member moves in the receiving pressure direction, the first and second ports communicate with each other, the compressed gas in the gas chamber is discharged through the first port and the second port, and as the pressure in the gas chamber decreases, the valve member It moves in the direction opposite to the receiving pressure direction, and communication between the first and second ports is cut off. In other words, the gas chamber is maintained at a pressure corresponding to the biasing force of the biasing means by discharging compressed gas or receiving supply of high-pressure gas by the movement of the valve member as the pressure increases or decreases.

(Effects of the Invention) Therefore, according to the present invention, even if the compressed gas expands or contracts due to temperature changes, the gas chamber is maintained at a pressure corresponding to the biasing force of the biasing means, so that the tool body A constant impact force can always be applied to the impact tool, and the reliability of the gas hydraulic impact tool can be improved.

(Example) Hereinafter, five embodiments of the present invention will be explained based on the drawings.

In the gas-type hydraulic impact tool shown in FIG. 1, 1 is a piston that impacts the rear end of a chisel (tool body) 2 of a rock drill, and is provided in a cylinder body 3 so as to be movable back and forth. A front chamber 4 and a rear chamber 5 are formed inside the piston 3, and a gas chamber 6 filled with compressed gas is provided behind the piston l.
is formed so as not to communicate with the rear chamber 5.

The front chamber 4 and the rear chamber 5 are connected to a hydraulic oil supply port 9 via first and second hydraulic oil supply passages 7 and 8, and an accumulator 10 is interposed in the first hydraulic oil supply passage 7. A valve 11 is interposed in the second hydraulic oil supply passage 8, and a valve means 12 is provided in the gas chamber 6.

The accumulator 10 includes a high-pressure gas chamber 10a filled with gas having a higher pressure than the compressed gas in the gas chamber 6, and a hydraulic chamber tab.
The hydraulic chamber 10b is in communication with the rear chamber 5 through a pore 13. Valve 11
receives the pressure of the hydraulic oil supply port 9 at its front end, receives the pressure of the front chamber 4 at its rear end via the recess 1a of the piston l, the valve switching passage 14, and the valve switching chamber 15, and moves back and forth,
The second hydraulic oil supply passage 8 is opened and closed. The recess 1a of the piston 1 communicates with a hydraulic oil return port 17 via a hydraulic oil return passage 16 when the piston 1 is moved back a predetermined distance from the forward position.

As shown in FIG. 2, the valve means 12 includes a valve chamber 20 formed in the cylinder body 3, a valve member 21 interposed in the valve chamber 20, and a biasing means (spring) 2.
2. The valve chamber 20 has a first port 24 communicating with the gas chamber 6 via a communication passage 23, a second port 26 communicating with an atmosphere opening passage 25, and a third port communicating with the high pressure gas chamber 10a via a gas supply passage 27. 28. The valve member 21 has a pressure receiving surface 21a at one end that receives the pressure of the compressed gas from the first port 24, and has a pressure receiving surface 21a at the other end that receives a biasing force from the biasing means 22 in a direction opposite to the receiving pressure direction P. , and can move forward and backward in the receiving force direction P.

An exhaust passage 29 is formed between the wall surface of the valve chamber 20 and the valve member 21, which communicates the first port 24 and the second port 26 by moving the valve member 21 in the receiving pressure direction P. In addition, an air supply passage 30 is formed in the valve member 21 by moving the valve member 21 in a direction opposite to the receiving pressure direction P. The operation of the gas-type hydraulic impact tool will be explained below.

First, the operation of the piston 1 will be explained.

When the piston 1 is in the forward position shown, a hydraulic pressure approximately equal to the pressure of the gas sealed in the accumulator 10 is applied from the hydraulic oil supply port 9 through the first hydraulic oil supply passage 7 and the front chamber 4 to the recess 1a.
In response to this, they began to retreat. When the piston 1 retreats a predetermined distance and the recess 1a communicates with the hydraulic oil return passage 16, the valve 11 moves back (
(moved to the left), the second hydraulic oil supply passage 8 is opened,
The piston l moves forward and hits the chisel 2, and at the same time hits the recess 1
Since the port a is no longer in communication with the hydraulic oil return passage 16, the pressure of the hydraulic oil acts on the valve switching chamber 15, the valve 11 closes, and the piston 1 moves backward again. Moreover, since the piston 1 compresses the compressed gas in the gas chamber 6 by retracting, the forward force is energized by the repulsive force of the compressed gas when the piston 1 moves forward.

Therefore, to explain the operation of the valve means 12,
When the pressure in the gas chamber 6 is in a state appropriate for the operation of the piston 1, the valve member 21 closes the second port 26 and the third port 28, and the gas pressure on the first port 24 side and the urging means 22 The biasing force of is balanced. In this case, the gas pressure is a low value Po (pressure when compressed gas is filled) when the piston 1 is moving forward because the volume of the gas chamber 6 is large, and when the piston 1 is moving backward, the gas pressure is a low value Po (pressure when compressed gas is filled in). Since the volume of is small and the compressed gas is compressed, the value Pm is high.
ax, and due to this change in gas pressure, the pressure receiving surface 21a of the valve member 21 slides between the A position shown in FIG. 2 and the B position shown in FIG. 3. In other words, since the biasing means 22 applies a biasing force to the valve member 21 that is proportional to the moving distance of the valve member 21 in the pressure receiving direction P, the gas The pressure and the above biasing force are balanced.

Then, if the outside temperature is low and the cylinder body 3 gets cold, the compressed gas in the gas chamber 6 contracts, or if there is a gas leak and the gas pressure becomes lower than PO.

As shown in FIG. 4, the valve member 21 moves in the direction opposite to the receiving pressure direction P by the urging of the urging means 22, and the first port 24
and the third port 28 communicate with each other via an air supply passage 30.

As a result, gas from the high pressure gas chamber 10a of the accumulator 10 is supplied to the gas chamber 6, and as the pressure in the gas chamber 6 increases, the valve member 21 moves in the opposite direction of the pressure receiving direction P to the position where the third port 28 is closed. Moving. Then, as the piston 1 moves back and forth, the valve member 21 moves back and forth, and the third port 28
By opening and closing the gas chamber 6 and supplying high-pressure gas, the gas chamber 6 eventually returns to a pressure appropriate for the operation of the piston 1.

On the other hand, if the outside temperature is high or the cylinder body 3 becomes hot due to the movement of the piston 1, and the compressed gas in the gas chamber 6 expands and the gas pressure exceeds Pmax, the valve member 2 moves in the pressure receiving direction P, and the first port 24 and the second port 26 communicate with each other via the exhaust passage 29. As a result, the compressed gas in the gas chamber 6 is released through the atmosphere opening passage 25, and as the pressure in the gas chamber 6 decreases, the valve member 21 closes the second port 26, and the gas chamber 6 becomes suitable for the operation of the piston 1. This will lead to a return to pressure.

Therefore, the gas chamber 6 is always maintained at an appropriate pressure, and fluctuations in the striking force of the piston 1 and malfunctions are eliminated.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal sectional view of a gas-type hydraulic impact tool, and FIGS. 2 to 5 are longitudinal sectional views showing the mode of operation of the valve means. ■... Piston, 2... Chisel (tool body), 3... Cylinder body, 6... Gas chamber, loa... High pressure Gas chamber, 12...
- Valve means, 20... valve chamber, 21... valve member, 21a... pressure receiving surface, 22... biasing means. 23... Communication passage, 24... First port, 25... Atmospheric release passage, 26... Second port, 27... Gas supply passage, 28...
...Third port, 29...Exhaust passage, 30.
...Air supply passage. 4■ Figure 5

Claims (1)

[Claims] (1) The cylinder body is equipped with a piston that moves back and forth by hydraulic pressure and a gas chamber filled with compressed gas that is compressed when the piston retreats, and uses the repulsive force of the compressed gas to urge the piston forward. In the tool body, the cylinder body has a first port communicating with the gas chamber, a second port for opening to the atmosphere, and a third port to which gas having a higher pressure than the compressed gas is supplied. A valve chamber is formed with a port, and one end of the valve chamber receives the pressure of the compressed gas from the first port, and is urged by a biasing means in a direction opposite to the pressure receiving direction. A gas-type hydraulic system, characterized in that a valve member is provided that communicates the first and second ports by moving in the opposite direction, and communicates the first and third ports by moving in the opposite direction. Percussion tools.