JPS5848064Y2 - Piston reciprocating switching valve in hydraulic impact device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic flow switching pulp for providing reciprocating motion to a piston in a hydraulic impact device.

As a means of destroying or crushing rocks, roads, buildings, etc., a double-acting hydraulic cylinder is installed inside the main body with a tool such as a chisel attached to the lower end, and a piston is reciprocated within this double-acting hydraulic cylinder. In addition to this, there is a hydraulic striking device in which the tool is struck with a hammer at the lower end of the upper chamber of the piston.

The most important structure in such a hydraulic impact device is a reduced pressure flow control means for automatically switching the flow of hydraulic fluid between the upper and lower portions of the piston to provide reciprocating motion to the piston.

Conventionally, as such reduced pressure flow control means, a control unit including a switching valve has been disposed outside the main body, but this increases the size of the device and makes it inconvenient to handle.

Therefore, the present inventor connected a control piston to the upper part of the striking piston, placed a switching valve coaxially with this control piston, and the control piston, which moves up and down together with the piston, automatically moves the switching valve to control the hydraulic pressure. We have proposed a hydraulic striking device with a structure in which the flow of piston flows into the upper chamber or lower chamber of the piston alternately.

According to this structure, the reduced pressure flow control can be performed within the main body in cooperation with the piston, so the device can be made into a slender shape that is easy to handle.

However, with this device, when there is a leakage of fluid pressure through the minute gap between the valve body and the valve chamber that accommodates it coaxially, the valve body tends to move inadvertently in the valve chamber, which causes the reduced pressure flow. There was a risk of control malfunction.

The present invention was developed based on the above fact, and is used in a switching valve that causes a flow of hydraulic pressure to alternately flow into the upper and lower chambers of a piston to produce a striking action. It is an object of the present invention to provide a control means that can stably hold a valve body, which is a switching element, at a predetermined position during an upward stroke or a downward stroke of a piston, except for f.

For this purpose, the present invention has a small diameter duct drilled in the valve body that fits the control piston in the valve chamber, one end of which communicates with the lower space of the valve chamber at all times, and the other end of which communicates with the outer diameter of the valve body.
When the valve body is in the upper position, the small-diameter duct works as a high-pressure liquid replenishment path for the space below the valve chamber, and when the valve body is in the bottom position, the small-diameter duct works as a high-pressure liquid discharge path from the space below the valve chamber. This allows the valve body to maintain the lower space of the valve chamber at a predetermined pressure even if there is a slight liquid leakage gap between the valve chambers.

Fig. 1 shows a hydraulic impact device equipped with a piston reciprocating switching valve according to the present invention. Equipped with tools 2 such as chisels, and an operation handle 3 on the upper side of the main body.
, 3, and an accumulator 4 is mounted on the top.

5 is a double-acting cylinder installed vertically on the bottom of the main body 1, and has a piston 7 inside, and a striking piston 19 is connected to the lower surface of the piston 7 coaxially with the tool 2;
The striking piston 19 protrudes into the cylindrical portion, and the hammer 8 is firmly connected to its tip.

Further, a rod-shaped control piston 18 is provided on the upper surface of the piston 7 coaxially with the striking piston 19.

The piston 7, the striking histone 19, and the control piston 18 are configured such that their respective diameters are w>w2>wl, and inside the double-acting cylinder, there are a piston upper chamber 51 and a piston lower chamber 52 that have free volume with the piston 7 as a boundary. is formed.

Reference numeral 6 designates a switching valve that is a feature of the present invention, and is composed of a valve chamber 9 formed through the double-acting cylinder 5 and a partition wall 17, and a valve body 10 accommodated in this valve chamber 9.

The control piston 18 extends through the partition wall 17 into the center of the valve chamber 9, and the control piston 1
A valve body 10 is fitted onto the outside of the control piston 18 in a relatively slidable relationship, and the valve body 10 is moved to an upper position or a lower position by the inflow and outflow of hydraulic pressure into and out of the valve chamber as the control piston 18 moves up and down. This causes the working fluid to alternately flow into the piston upper chamber 51 or the piston lower chamber 52, thereby giving the piston 7 reciprocating motion.

Reference numeral 11 denotes an inclined protrusion connected to the lower side of the top of the main body 1, and the inclined protrusion 11 has an inlet passage 13 that can communicate with an upper chamber 12 formed between the accumulator 4 and the valve chamber 9.
is bored therein, and an outlet passage 14 is bored parallel to and adjacent to the inlet passage 13.

An operating valve 15 is installed in the inlet passage 13 and the outlet passage 14 in a relationship that intersects with them, and an operating lever 16
By directly connecting the inlet passage 13 and the outlet passage 14, or by making the artificial passage 13 and the outlet passage 14 non-communicating, the hydraulic oil is allowed to flow through the main body and then discharged through the outlet passage 14. .

Figures 2 and 3 show the details of the switching valve. First, the control piston 18 is provided with a stool-shaped duct 20, which opens at one end in the upper end surface and at the other end in the side wall. A recessed duct 21 is provided below this duct for discharging the hydraulic pressure in the lower chamber of the valve chamber, which will be described later, to the outlet passage 14 during the switching period between the upward and downward movements of the piston.

On the other hand, the valve chamber 9 has a lower flange 2 of the valve body 10 at the bottom.
In addition to having a cylindrical lower chamber 94 for accommodating 2, ring-shaped first to fourth recesses 9L91' and 92°93 are formed from the top to the bottom.

For such a valve chamber 9, the valve body 10 has the lower flange 22 as described above, and also has an upper flange 23 facing the lower flange 22 at a predetermined distance.

This upper flange 23 is made to have the same outer diameter as the lower flange 22, and when raised, the third recess 92
When it comes into contact with the bottom of the recess, it reaches its rising limit, and during the descending period, it comes into contact with the protruding peripheral surface 95 between the third recess 92 and the fourth recess 93, blocking both of the recesses.

Between the lower flange 22 and the upper flange 23, a third recess 92 and a fourth recess 93 are communicated to form a relay path 96.
A cylindrical recess 24 is formed to obtain the following.

The upper flange 23 is connected with an annular head 25 for blocking the connection between the first recess 91 and the upper chamber 12 in the normal state and during the piston rising period.

A ring-shaped hole 26 having a predetermined depth from the lower end is formed on the inner diameter side of the valve body 10, and this ring-shaped hole 26
A small diameter duct 26' is bored from the tip of the valve body to the outer diameter side of the valve body.

The narrow diameter duct 26' is configured at an inclination angle such that it communicates with the second recess 91' when the valve body 10 is in the upper position, and communicates with the third recess 92 when the valve body 10 is in the lower position. has been done.

Although the ring-shaped hole 26 is formed in this embodiment,
Depending on the height of the valve body 10, the ring-shaped hole 26 may be omitted.
A small diameter duct 2°6' may be bored from the outer diameter part to the bottom part.

A passage 27 connecting the upper chamber 12 and the piston lower chamber 52 is bored inside the main body outside the valve chamber 9, and the second recess 91' is connected to the passage 27. It is communicated.

On the other hand, the outlet passage 14 communicates with the third recess 92, and a discharge passage 28 is branched from the intermediate position of the outlet passage 14, and the other end of this passage is connected to the valve chamber lower chamber 94 and the partition wall 11. It is connected to a recess 29 formed concentrically with the control piston.

This recess 29 communicates with the duct 21 of the control piston 18 at the time of switching the piston up and down, and is connected to the lower chamber 94.
This is for guiding the hydraulic oil inside to the discharge passage 28.

Furthermore, a passage 30 connecting the first recess 91 and the piston upper chamber 51 is bored in the main body at a different cross-sectional position from the passages 27 and 28, and a passage 30 connecting the first recess 91 and the piston upper chamber 51 is bored. A passage 31 connecting the chambers 51 is bored.

Next, the operation of the present invention will be explained.

To operate the hydraulic impact device, press the operating lever 1.
6 moves the working pulp 15 and makes the inlet passage 13 and the outlet passage 14 non-communicating.

In this way, as shown in FIG. 4, the high-pressure hydraulic fluid becomes flow A, which is led to the piston lower chamber 52 through the upper chamber 12 and the passage 27, and is generated due to the difference in area between the piston lower chamber 52 and the control piston 18. The force pushes the piston 7 and... mer 8 upward.

At the same time, the control piston 18 located above the piston 7 is also pushed upward.

At this time, the hydraulic fluid in the piston upper chamber 51 becomes a flow B, passes from the passage 31 through the relay passage 96 constituted by the third and fourth recesses 92 and 93, and flows out from the outlet passage 14.

In addition, high-pressure hydraulic fluid is supplied to the spool-shaped duct 20 and the valve body 10.
It flows into the lower chamber 94 of the valve chamber through the ring-shaped hole 26, and makes this and the upper chamber 12 have the same pressure.

Since the lower area of the valve body 10 is larger than that of the upper part,
The force generated by this area difference keeps the valve body 10 in the upper position as shown.

Further, the high pressure hydraulic oil flowing from the inlet passage 13 is
As shown in the figure, when the piston 7 is pushed up, the upper chamber 12
The flow then becomes a flow D and enters the accumulator, pushes up the diaphragm 44 while compressing the sealed gas (nitrogen gas, etc.), and the pressure is accumulated in the oil storage chamber 45.

On the other hand, the control piston 18 is pushed up together with the piston 7, and the duct 21 provided there is connected to the valve chamber lower chamber 9.
4 and the recess 29, the high-pressure hydraulic oil that had kept the valve body 10 at the upper limit position becomes a flow C and flows from the lower valve chamber 94 through the duct 21 and the discharge passage 28. It flows out from the outlet passage 14.

As a result, the valve body 10 becomes free and is pushed down along the control piston 18 by the action of the high pressure in the upper chamber 12, so that the lower position, that is, the lower flange 22 contacts the bottom of the lower valve chamber 94, and the upper flange 23 touches the bottom of the valve chamber 94. It stops at a position in contact with the cylindrical surface 95.

When the valve body 10 reaches the lower position in this way, the space between the third recess 92 and the fourth recess 93 is closed by the upper flange 23, and at the same time, the annular head 25 is lowered to open the upper chamber 1.
2 and the first recess 91 are brought into communication.

Therefore, as shown in FIG. 6, the high-pressure hydraulic oil becomes a flow E and flows from the upper chamber 12 into the piston upper chamber 51 through the first recess 91 and the passage 30.

The area of the piston upper chamber 51 is much larger than that of the piston lower chamber 52.

Therefore, the striking piston 19 is suddenly pushed downward by a force corresponding to the area difference.

Moreover, at this time, the hydraulic oil stored in the accumulator 4 is released as a flow E, which passes through the upper chamber 12 and accelerates the control piston 18.

Further, the hydraulic oil in the piston lower chamber 52 is pushed out to the passage 2.
7, flows back into the upper chamber 12 as a flow F, and presses the control piston 18.

The piston 7 is rapidly accelerated downward by the resultant force of the pressure on the entire upper and lower areas, and the hammer 8 at the tip of the striking piston 19 strikes the tool 2.

This is the state shown in Fig. 7. Almost at the same time as the hammer 8 hits the tool 2, the spool-shaped duct 20 of the lowered control piston 18 and the ring-shaped hole 26 of the valve body 10 are connected, and the high pressure is activated. The oil becomes a flow G and is sealed in the lower chamber 94 of the valve chamber.

As a result, the valve body 10 is pushed up by the force caused by the difference in area between the upper and lower parts of the valve body 10, and returns to the state shown in FIG. The passage 30 to the chamber 51 is blocked, and at the same time, the third recess 92 and the fourth recess 93 are communicated with each other by the cylinder second recess 24 of the valve body 10, so that the piston upper chamber 51 is connected to the passage 3.
1 communicates with the outlet passage 14, and the piston 7 is pushed up by the high-temperature hydraulic oil from the flow path 2γ that connects the upper chamber 12 and the piston lower chamber 52.

Thereafter, by repeating the same operation, the tool 2 is continuously hit.

Thus, when the valve body 10 is in the upper position, high pressure liquid is supplied to the lower chamber 94 of the valve chamber through the spool-shaped duct 20 of the control piston 18 and the ring-shaped hole 26 of the valve body.
This is sealed in the lower valve chamber 94 as the control piston 18 rises, so high pressure acts on the lower valve chamber 94. The fourth recess 92, 93 and the lower recess 29 are each connected to the outlet passage 14 and are therefore always under low pressure.

Then, the F section flange 22 of the valve body 10 and the lower valve chamber 94
There is a gap, albeit slight, between the outer peripheral surface of the control piston 18 and the wall surface of the through hole constituting the recess 29.

Therefore, the liquid in the valve chamber lower chamber 94 leaks to the low pressure side through this gap, and the pressure in the valve chamber lower chamber 94 tends to decrease due to this liquid leakage.

However, in the present invention, a small diameter duct 26' is bored in the valve body 10, and when the valve body 10 is in the upper position, the second recess 91' and the valve are connected through the small diameter duct 26'. It is designed to communicate with the lower chamber 94.

The second recess 91' communicates with the passage 27, and is always at high pressure due to the inflow of high pressure liquid from the upper chamber 12.

Therefore, high-pressure liquid constantly flows into the lower chamber 94 of the valve chamber through the path of the second recess 91' - the small diameter duct, and the ring-shaped hole 26', thereby automatically eliminating the pressure leakage from the gap. will be supplemented.

Therefore, the lower chamber 94 of the valve chamber is maintained at the desired high pressure, and the valve body 10
is maintained in an extremely stable state.

On the other hand, when the valve body 10 is in the lower position, the pressure in the lower valve chamber 94 is low, while the fourth recess 93 above it is high pressure because it is blocked from the outlet passage 14.

Therefore, the hydraulic fluid enters the lower valve chamber 94 from the fourth recess 93 through the gap K, increases the pressure in this chamber, and exhibits a behavior that lifts the valve body 10.

However, in the present invention, in this state, the small diameter duct 26
' communicates the valve chamber 94 and the third recess 92.

This third recess 92 communicates with the outlet passage 14 and is always under low pressure.

Therefore, even if high-pressure liquid enters the lower chamber 94 of the valve chamber from the upper recess, this liquid will flow through the ring-shaped hole - small diameter duct 26' -
The third recess 92-outlet passage 14 path is automatically evacuated, so that the lower valve chamber 94 is maintained at the desired low pressure.
In this case as well, the valve body 10 can be held extremely stably.

According to the present invention as described above, in a switching valve for a hydraulic impact device that causes a flow of hydraulic fluid to flow alternately into an upper chamber or a lower chamber of a piston to produce an impact action, the valve body is used as a flow path switching element. can be reliably and stably held at a predetermined position within the valve chamber during the upward stroke and downward stroke of the piston.

This makes it possible to smooth the flow of the hydraulic fluid and give smooth reciprocating motion to the piston.It also reduces the need to finish the sliding surfaces of the valve body, valve chamber, and control valve, making manufacturing easier. Effects can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an example of a hydraulic impact device equipped with a piston reciprocating switching valve according to the present invention, and FIG. 2 is a cross-sectional view showing the main parts of the present invention with the valve body in the upper position. Figure 3 is a cross-sectional view showing the valve body in the lower position;
7 to 7 are cross-sectional views showing the operation of the hydraulic striking device equipped with the valve of the present invention step by step. 6...Switching valve, 9...Valve chamber, 10...Valve body,
18... Control piston, 26... Link-shaped hole, 26'... Small diameter duct, 51... Piston upper chamber, 52... Piston lower chamber, 94... Valve chamber lower chamber.

Claims (1)

[Scope of utility model registration request] A valve body 10 and a valve chamber 9 that controls the valve body 10 are arranged coaxially with a control piston 18 that is directly connected to a piston 7 in a double-acting cylinder, and hydraulic pressure flows in and out of the valve chamber as the control piston 18 moves up and down. Move the valve body 10 by
In the switching pulp in which the hydraulic fluid is alternately introduced into the upper chamber or the lower chamber of the piston to give reciprocating motion to the piston, one end of the valve body 10 is always connected to the lower chamber 94 of the valve chamber and the other end is the outer diameter of the valve body. A small diameter duct 26 leading to the valve body 10 is provided.
A reciprocating piston in a hydraulic impact device characterized in that high-pressure liquid is supplied to the lower chamber 94 when the valve body 10 is in the upper position, and leaked high-pressure liquid is discharged from the lower chamber 94 when the valve body 10 is in the lower position. Dynamic switching valve.