JPS5818196B2 - hydraulic breaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an improvement in a hydraulically operated hydraulic breaker for concrete and rock crushing.

The present applicant has already provided Japanese Patent Application No. 51-017670 as a new structure and configuration for a hydraulic breaker. In order to facilitate the explanation of this invention, the gist of the said Japanese Patent Application No. 51-017670 will be briefly summarized in FIG. 1 and the following explanation. Let's show this.

FIG. 1 is a longitudinal sectional view showing the gist of Japanese Patent Application No. 51-017670, and the hydraulic circuit is indicated using JIS BO125 hydraulic and pneumatic symbols.

1 is a striking piston, and the upper and lower parts are central pistons 2 (
The upper piston 3 is made thinner than the diameter D1) and has a small diameter D2.
and forms a lower piston 4 with a medium diameter D3.

The main body 5 is provided with a cylinder chamber 6 in which the striking piston 1 can be stored, and the striking piston 1 is installed so that it can be stored vertically.

As shown in the figure, a fluid source 9 branches off from a fluid source 9 and hydraulic pressure is directly introduced into a lower chamber 7 formed between a cylinder chamber 6 of the main body 5 and the striking piston 1.
It is designed to prevent leakage between the piston and the piston and to provide an upward thrust to the striking piston 1.

A fluid source 9 is connected to an upper chamber 8 formed in the upper part of the cylinder chamber 6 by the impact piston 1 via a control valve 10 as shown.

The function of the control valve 10 is a 3-port switching valve, and when the impact piston 1 descends to the lower end, the fluid in the upper chamber 8 led through the guide hole 11 switches the control valve 10 and moves the control valve 10 to the discharge position 12. The switch is switched, and the fluid in the upper chamber 8 is discharged.

In this state, the impact pin 1 rises due to the fluid pressure acting on the lower chamber 7, and when it reaches the upper end, the guide hole 13
The control valve 10 is switched to the supply position 14 by the hydraulic pressure guided to the control valve 10, fluid is supplied to the upper chamber 8, a downward thrust is generated in the striking piston 1 due to the relationship D3>D2, and the striking piston 1 is descend.

In this way, in the structure and configuration shown in FIG. 1, the striking piston 1 vibrates up and down due to hydraulic pressure, and
The chisel 15 crushes concrete and rocks.

This kind of hydraulic breaker (mainly uses hydraulic pressure discharged by a hydraulic pump, so it is called a hydraulic breaker).

), the inertia energy of the vertical movement of the striking piston 1 is effectively used, the pulsation of the hydraulic pressure is minimized, the accumulators 16 and 17 provided in the circuit are made small, and the hydraulic energy is used effectively. Therefore, a gas chamber 18 is provided in a part of the main body 5, and when the piston 3 rises, the sealed gas in the gas chamber 18 is compressed, and when the striking piston 1 descends, the compressed pressure of the sealed gas is also compressed. The above-mentioned patent application 1973-1 was designed to be able to add downward thrust.
017670.

In addition, the structure shown in FIG. 1 is simplified, and the pulsation of the hydraulic pressure becomes a little large.) As shown in FIG. A method of vibrating the impact screw I/N 21 by supplying and discharging hydraulic pressure is also used.

In FIG. 2, 23 is the upper piston, 25 is the main body, and 28
The upper chamber 38 is a gas chamber, and 29 is a hydraulic pressure source.

However, for such a gas chamber 18 or 38, there is an optimum volume and an optimum pressure corresponding to the volume, and if friction loss (including loss due to fluid flow) is ignored, the volume is equal to or smaller than the gas chamber 18. Compression energy L within 38
Since the fluid pressure is obtained as the point where the energy E consumed in the rising-stroke of the impact screws 1 to 1.21 becomes equal, PV-PV L-□・・・・・・・・・ (5) 1- γ Pl...Pressure in the gas chamber at the lower end of the striking piston (filling pressure) ■1... Volume of gas at the lower end of the striking piston P2... Gas chamber at the upper end of the striking piston Pressure ■2...Volume γ in the gas chamber at the upper end of the striking piston...PolJ, I-rope index or E=P-8・-(Dl-D3)-W-S・・・・・・・(
B) P...Liquid pressure S...Stroke of striking piston W...
. . . is the weight of the impact screw]. Also, according to the law of gases, Pt■17=P2V2''--(C), so if we set L=E and find ■1, we get P2
v2-P1■1--(Dl-D3)P-8-W-8...
・・・・・・・・・(Shun-(D, -D3) P-8-W-S ■-□ ・・・・・・・・・(E) ”YoP γ P2(”)P.

2 becomes.

The minimum optimal volume is the point where Pl is set to atmospheric pressure in equation (E).

(The reason will be explained later) When this optimum capacity is actually calculated, the volume becomes close to the piston displacement amount of the upper bistoy 3 or 23 at the preferable hydraulic pressure and the size of the striking pistons 1 and 21.

In other words, the size is extremely close to the minimum size that can be provided within the main body 5.

On the other hand, if the volume inside the gas chamber 18 or 38 is small, some gas leakage will occur due to the vertical vibration of the striking piston 1 or 21, but due to this influence, the gas pressure sealed in the gas chamber 18 or 38 will gradually decrease. It goes down.

If the gas chamber 18.38 is large, even if some gas leaks, the gas pressure will not be affected greatly;
If 8 is small, even a slight leak will greatly affect the gas pressure, and the operating period after filling with gas will be short, and the gas will have to be filled again.

This invention was made by focusing on these interrelationships, namely, the fact that the volume of the gas chamber 18.38 needs to be extremely small in order to operate efficiently, and the initial optimal sealing pressure in the case of the minimum volume is atmospheric pressure. It was.

In order to determine whether maximum efficiency can be achieved when the gas chamber 18.38 becomes close to the minimum volume, that is, the displacement amount (piston diameter x stroke) of the upper pistons 3, 23, consider the following:
be easily understood.

That is, if the gas chambers 18, 38 are of infinite size, the pressure in the gas chambers 18, 38 is equal to the striking piston 1, 38.
There is no change even with the vertical movement of 21.

Therefore, the effect of the presence of the gas chamber 18.38 is simply to increase the downward thrust, i.e. in the example of FIG.
Either the diameter D3 of the striking piston 1 is increased to correspond to the downward thrust, or the weight of the striking piston 1 is simply increased by an amount corresponding to the downward thrust.

Also, in FIG. 2, the weight of the striking piston 21 is increased or a part of the hydraulic pressure is used as a downward thrust as shown by the chain line 40 in FIG.
the percussion piston 1 in reversal from the upward direction to the downward direction at the upper end of the stroke of the percussion piston 1 or 21;
The inertia of 21 means that the hydraulic pressure is reversed when the control valve 10 or 30 is reversed.
It is absorbed by the hydraulic pressure acting on the upper chamber 8.

However, as an extreme example, if the gas chamber 18.38 is made to have a volume corresponding to the displacement of the pistons, the striking pistons 1 and 2
1 is at the lower end, the gas chamber 18°38 is assumed to be at atmospheric pressure.[As the volume of the gas chamber 18°38 increases, it is preferable to increase the sealing pressure, and the optimal pressure for the size of the gas chamber is hydraulic pressure, central piston 2
, converges to a constant value determined by the upper piston 3 and the lower piston 4.

] With such a configuration, when the striking pistons 1, 21 start from the lower end, they easily accelerate and rise rapidly because there is no downward thrust due to gas pressure.

Gas pressure increases as it rises, and at top dead center gas chamber 1
8.Since the volume of 38 becomes zero, the gas pressure becomes infinite,
The upward energy of the striking pistons 1, 21 is completely converted into gas pressure, which is used as an initial downward thrust when the pistons 1, 21 descend.

Of course, in reality, it is not possible to make the volume of the gas chamber 18.38 equal to the amount of piston displacement and raise the gas pressure to infinity, but it is possible to increase the volume of the gas chamber 18.38 from infinity to the piston displacement. If we consider the period up to the equivalent displacement, if it is infinite, the repulsive force of the gas cannot be used and a downward thrust is always generated, whereas the gas chamber 18.
When the volume of 38 becomes smaller, the gas pressure increases as the stroke of the striking piston 1 increases, and the upward inertial force of the striking piston 1 is converted into gas pressure, which can be used downward.

In other words, it can be understood that the repulsion based on gas compression becomes effective.

To give a practical example, D = 16.5cfrLD = 15.
5CrtID3=15.0CrrL2 P=140kgf Shoulder 5-10 box W=100 and the optimum volume V=1935i.

The piston displacement amount at this time is 1887i, and the volume of the gas chamber at the top dead center of the striking piston is 48i.

In this invention, in addition to the above-mentioned points,
As shown in the figure (sectional view of main parts), a small-capacity gas chamber 48 is provided within the main body 45, and this gas chamber 48 is communicated with the outside atmosphere via a check valve.

In FIG. 3, 41 is a striking piston, 43 is an upper piston of the striking piston 41, 45 is a main body, and 48 is a gas chamber having an optimum volume as described above.

60 is a through hole provided in the main body 45 so as to communicate with the gas chamber, and 61 is a valve chamber provided in a part of the through hole 60, into which a ball 62 is installed as a check valve.

When the ball 62 is located on the left side in the figure, the ball 62 is located in the through hole 6.
When located on the right side, the valve seat 63 is in close contact with the valve seat 63 as shown in the figure, and the fluid in the gas chamber 48 is allowed to escape to the right side. It is being done in such a way that it is

Regarding the structures and configurations of the valve seat 63 and the ball 62, in addition to the configuration shown in the drawings, there are various structures and configurations conventionally known as check valves, and any of these can be usefully utilized in the present invention. .

In FIG. 3, 64 is a filter element provided between the through hole 60 and the outside air.

In such a configuration, when the impact piston 41 is at the lower end, the filter element 64 is located in the gas chamber 48.
Atmospheric air easily enters through the ball 62 of the check valve.

When the striking piston 41 starts to rise from this state and compresses the air in the gas chamber 48, the ball 62 of the check valve is pulled by this pressure and comes into close contact with the valve seat 63, and the air in the gas chamber 48 is sufficiently compressed. It will be.

Ideally, no air leaks from the gas chamber 48 during this compression process, but the upper piston 43 and the main body 4
It is also possible that some leakage may occur from the seal between the parts and the parts 5 and 5.

If such a leak occurs, when the striking piston 41 descends, the gas chamber 48 will have a negative pressure with respect to the atmosphere, so the ball 62 of the check valve will not easily come off the valve seat 63.
Atmospheric pressure enters the gas chamber 48 through the filter element 64, and when the striking piston 41 is at the lower end, atmospheric pressure always exists in the gas chamber 48, and the hydraulic breaker always operates under the most ideal conditions. In addition to being operated with high speed, the structure is also extremely simple.

The check valve can be provided not only in the main body 45 described above, but also in the center of the striking piston 41, as shown in FIG. 7
2. If the valve seat 73 and ball 74 are provided as shown in the figure, and the proper direction of the check valve is directed from the gas chamber 48 to the lower end of the striking piston 41, the same effect as that shown in FIG. 3 can be obtained. In addition, the effect of killing two birds with one stone can be achieved by alleviating the stress concentration in the central portion of the striking piston 41.

In addition, as a substitute for a check valve, as shown in FIG. 5 (longitudinal cross-sectional view of main parts), a guide hole 81 opened at the lower end of the piston allows communication between the atmosphere and the gas chamber 48 whenever the piston 41 is located at the lower end. You can get the same effect by doing this.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of one conventional embodiment, Fig. 2 is a longitudinal sectional view of another conventional embodiment, Fig. 3 is a sectional view of essential parts of an embodiment of the present invention, and Fig. 4 is a longitudinal sectional view of another conventional embodiment. 5 is a sectional view of a main part of another embodiment of the invention. FIG. 5 is a sectional view of a main part of another embodiment of the invention. Next, 1 is a striking piston, 2 is a central piston, 3 is an upper piston, 4 is a lower piston, 5 is a main body, 6 is a cylinder chamber, T is a lower chamber, 8 is an upper chamber, 9 is a fluid source, 10 is a Control valve, 11 is a guide hole, 12 is a discharge position, 13 is a guide hole, 14
is the supply position, 15 is the chisel, 16 is the accumulator, 1
7 is an accumulator, 18 is a gas chamber, 21 is a striking piston, 23 is an upper piston, 25 is a main body, 27 is a lower chamber, 28 is an upper chamber, 29 is a liquid source, 30 is a 38 is a gas chamber; 4 is a control valve;
1 is a striking piston, 43 is an upper piston,
45 is the main body, 48 is a gas chamber, 55 is a chisel, 60 is a through hole, 62 is a ball, 63 is a valve seat, 64 is a gas chamber, 71 is a guide hole, 72 is a valve room, 73
is a valve seat, 74 is a ball, and 81 is a guide hole.

Claims (1)

[Scope of Claims] 1. A hydraulic breaker in which air in a gas chamber provided above the striking piston is compressed and expanded by a striking piston vibrated by hydraulic pressure, and the air is compressed and repulsed. A hydraulic breaker characterized in that a check valve is provided between. 2. The hydraulic breaker according to claim 1, wherein the gas chamber and the atmosphere are communicated with each other by a check valve provided within the main body. 3. The hydraulic breaker according to claim 1, wherein the gas chamber and the atmosphere are communicated through a check valve provided in a guide hole provided in the striking piston. 4. The hydraulic breaker according to claim 1, wherein the gas chamber and the atmosphere are communicated through a through hole opened at the lower end of the striking piston.