JPH0763943B2 - Hydraulic breaker - Google Patents

Description

The present invention relates to a hydraulic breaker having a striking piston.

[Prior art]

A method for adjusting the striking stroke of a hydraulic breaker has been proposed in Japanese Patent Publication Nos. 61-4628 and 61-54916.

In the conventional hydraulic breaker, a reciprocating reversal position detecting means is provided by a plurality of grooves provided in the cylinder, and one groove is formed between the groove and a control valve for controlling the reciprocating reversal of the striking piston. Alternatively, a throttle may be provided in the passage from the groove to the control valve to utilize the delay of the inverted signal.

In the method of adjusting by one shift valve described above, since the spool in the shift valve selects one of the ports communicating with the plurality of grooves, it is necessary to stop and hold the intermediate position of the stroke, and the spool is subjected to the spring force. It is very difficult to maintain the signal pressure balance accurately in place. In particular, there is a great risk that the balance may be easily lost due to a leak due to an increase in oil temperature or a pressure change generated during the operation of the breaker, and the spool may change from a predetermined position.

The method of utilizing the time delay by using the throttle has a problem that it is easily affected by an increase in leak due to an increase in oil temperature and a variation in products due to processing accuracy, which makes accurate adjustment operation difficult.

[Problems to be Solved by the Invention]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above conventional problems and provide a hydraulic breaker capable of stroke adjustment with high reliability under remote control.

[Means for Solving the Problems]

The present invention solves the above problems by providing a plurality of additional reciprocating reversal positions at positions of strokes additionally adjusted in addition to one reciprocating reversal position detecting means, for example, a circuit connecting a groove in a cylinder and a control valve. Each additional reciprocating motion reversal position detecting means is connected to a control valve through a stroke control valve having an on-off valve section that operates independently to switch one or more on-off valve sections by a remote signal. The hydraulic breaker is characterized by adjusting the reciprocating reversal position for switching the control valve.

[Action]

According to the present invention, the reciprocating reversal position detecting means is switched to high and low pressure according to the movement of the striking piston, and the pressure change switches the control valve to change the pressure acting on the striking piston to reverse the reciprocating motion. To do. At this time, when one or more of the valve portions connected to the additional reciprocating reversal position detecting means are switched by the signal pressure, the additional reciprocating reversal position detecting means is communicated with the control valve.

The additional reciprocating motion reversal position detecting means switches the hydraulic pressure between high and low when the striking pistons reach the respective stroke positions. The impact piston is reciprocally reversed at the time when this change in pressure is first transmitted to the control valve through the valve portion.

According to the present invention, each valve portion is formed as an opening / closing valve, and the opening / closing is surely switched by the signal pressure, and the additional reciprocating motion reversal position detecting means and the control valve are always reliably opened / closed. Therefore, the stroke can be reliably adjusted.

〔Example〕

 The details of the present invention will be described based on the embodiments shown in the drawings.

In the figure, a hydraulic breaker 1 includes a cylinder 2, a striking piston 4 that is slidably guided in the cylinder 2 to strike a chisel 3, a control hull 5 that reverses the movement direction of the striking piston 4, and the striking piston 4 And a stroke adjusting device 6 for adjusting the stroke.

The striking piston 4 receives the hydraulic pressure in the opposite directions.
It has a pressure receiving surface 7 and a second pressure receiving surface 8. First close to chisel 3
The pressure receiving surface 7 has a pressure receiving area smaller than that of the second pressure receiving surface 8 on the side away from the chisel 3.

The cylinder 2 is formed with a first pressure chamber 9 containing pressure oil that exerts pressure on the first pressure receiving surface 7 and a second pressure chamber 10 containing pressure oil that exerts pressure on the second pressure receiving surface 8. It First
The pressure chamber 9 is connected to the high pressure source 12 by the first conduit 11 and is constantly supplied with pressure oil. As shown in the figure, the control valve 5 may be interposed between the first conduit 11 and the high pressure source 12. The second pressure chamber 10 is connected to the control valve 5 by the second conduit 13.

In the cylinder 2, a first annular groove 14 as a reciprocating reversal position detecting means and a second annular groove 15 are further formed between the first pressure chamber 9 and the second pressure chamber 10, and the first annular groove 14 is The third conduit 16 connects the control valve 5 and the stroke adjusting device 6, and the second annular groove 15 connects the low pressure line 18 by the fourth conduit 17.
Connected with.

The control valve 5 includes a valve body 19 and the valve body.
And a control piston 20 which is slidably guided in 19.

The control piston 20 includes an axial through hole 21 and three pressure receiving surfaces formed on the outer peripheral surface and having different pressure receiving areas.
It has a first step portion 22, a second step portion 23, and a third step portion 24.
The pressure receiving surface of the first step portion 22 is the same as the pressure receiving surface of the second step portion 23.
It is almost equal to the sum of 24 pressure-receiving surfaces.

In the valve body 19, the first oil chamber 25 into which the pressure oil that acts on the first step portion 22 enters, the second oil chamber 26 which is always connected to the low pressure line 18, and the third step portion 24 are pressurized. A third oil chamber 27 is formed in which the working pressure oil enters. The first oil chamber 25 is connected to the first annular groove 14 of the cylinder 2 by the third pipe line 16,
The oil chamber 27 is connected to the high pressure source 12.

The operating principle of the control valve 5 and the striking piston 4 will be described.

In the state shown in the figure, the high pressure acts on the first pressure chamber 9 of the cylinder 2 and the low pressure of the second pressure chamber 10 is low. That is, the second oil chamber 26 of the control valve 5 has the control piston 20
Since the lateral hole 30 communicates with the through hole 21, the second pressure chamber 10 has a low pressure. The striking piston 4 is returned to the upper side in the drawing by the pressure of the first pressure receiving surface 7. At this time, in the control valve 5, the first oil chamber 25 and the second oil chamber 26 are at low pressure, and the third oil chamber 27 is at high pressure.
Are held in the positions shown.

When the striking piston 4 moves back by the stroke S, the first pressure receiving surface 7 is located in the first annular groove 14, and the first annular groove 14 moves to the first annular groove 14.
The first oil chamber 25 of the control valve 5 communicating with the pressure chamber 9
Changes into a state where high pressure acts. This change in pressure causes the control piston 20 to move to the first step portion 22 and the third step portion.
Although both 24 receive high pressure, there is a difference in pressure receiving area, so they start moving upward in the figure. When the control piston 20 moves, the high pressure oil flows into the second pressure chamber 10 through the through hole 21 and the second pipe line 13, and the first pressure receiving surface 7 of the striking piston 4 and the second pressure receiving surface 7
Although a high pressure acts on the pressure receiving surface 8 as well, the force acting on the striking piston 4 becomes downward due to the difference in the pressure receiving area, the striking piston switches its movement direction, and starts forward movement, that is, striking movement.

When the striking piston 4 starts to move forward, the first pressure chamber 9 and the first pressure chamber 9
The hydraulic pressure is cut off from the annular groove 14, and the first annular groove 14 and the second annular groove 15 are communicated with each other at a position immediately before the striking piston 4 strikes the chisel 3. The first oil chamber 25 communicates with the low pressure line 18 and changes to a low pressure. By changing the first oil chamber 25 to a low pressure, the control piston 20 returns to the above-mentioned initial state in the lower part of the figure.
The control piston 20 returns and the horizontal hole 30 causes the second hydraulic pressure.
When the 26 and the through hole 21 communicate with each other, the second pressure chamber 10 of the cylinder 2 changes to a low pressure. The striking piston 4 starts rebounding due to the repulsion of the striking piston 4 against the chisel 3 and the change in the pressure of the second pressure chamber 10 due to the switching movement of the control piston 20. The control valve 5 thus acts as a movement direction switching means for the striking piston 4.

The stroke adjusting device 6 adjusts the striking stroke of the striking piston 4 to an appropriately short stroke by maximizing the stroke determined based on the stroke S.

The stroke adjusting device 6 includes a first groove 31 as additional reciprocating reversal position detecting means formed at a predetermined stroke S ₁ , S ₂ , S ₃ from the striking position of the striking piston 4 with respect to the chisel 3, and a second groove 31. Groove 32, third groove 33 and stroke control valve
Have 34.

The stroke control valve 34 has a respective stroke, in the illustrated example, a first stroke S ₁ , a second stroke S ₂ , and a third stroke.
Opening / closing valve unit for 1 unit corresponding to 3 types of strokes of S ₃ ,
For example, it has a first valve portion 34a, a second valve portion 34b, and a third valve portion 34c.

The stroke control valve 34 includes a first oil chamber 25 and a first oil chamber 25 used for switching control of the control valve 5 at the maximum stroke.
As a bypass for the third conduit 16 that connects the annular groove 14, a connection switching action that connects the first oil chamber 25 and each groove 31, 32, 33 is performed. The stroke is automatically set to the maximum stroke when the stroke adjusting device 6 is not activated.

The bypass conduit 16a for the third conduit 16 is connected to the respective first ports of the first valve portion 34a, the second valve portion 34b, and the third valve portion 34c, and the second port of the first valve portion 34a is a connection pipe. 35 by the first groove 3
1, the second port of the second valve portion 34b is connected to the second groove by the connecting pipe 36.
32, the second port of the third valve portion 34c is connected to the third port by the connecting pipe 37.
It is connected to the groove 33.

The first valve portion 34a, the second valve portion 34b, and the third valve portion 34c each have a spool 38 and a spring 39, and are individually switchable.
The valve portions 34a, 34b, 34c can be formed as one valve in one casing or can be constructed as a combination of individual valves. Each valve part 34a, 34b, 34c
The spool 38 simultaneously receives a signal pressure from a remote control device from one end through a signal line 40. The other end of the spool 38 is connected to the force of the spring 39 and the low pressure line 18. Each valve
The force of the spring 39 of 34a, 34b, 34c is set so that each valve section is switched by a signal pressure of a different pressure. Generally the first groove corresponding to the shortest stroll S ₁
The first valve portion 34a connected to 31 has the highest signal pressure Pa
Then the second valve portion 34b is a signal pressure Pb which is connected to the second groove 32 corresponding to a short stroke S ₂ Second, third valve connected to the third groove 33 corresponding to the third stroke S ₃ Part 34c
Is switched with the lowest signal pressure Pc. That is, Pc <Pb <
The spring 39 is set for each Pa.

When the stroke switching device is operated, the signal pressure Pv is simultaneously sent from the remote control device to the respective valve parts 34a, 34b, 34c through the signal line 40. When the signal pressure is Pc <Pv <Pb, the spool 38 is switched against the force of the spring 39 only in the third valve portion 34c, the bypass pipe line 16a and the connection pipe 37 are communicated, and the third groove 33 is formed. It communicates with the first oil chamber 25 of the control valve 5. When the signal pressure Pv is Pb <Pv <Pa, the third valve unit 34
In the c and the second valve portion 34b, the spool 38 is moved and switched against the force of the spring 39, and the third groove 33 and the second groove 32 are moved to the first oil chamber.
Connected to 25. When the signal pressure Pv is Pa <Pv, the first valve section
Since all the spools 38 of 34a to the third valve portion 34c are moved and switched, all of the first groove 31, the second groove 32, and the third groove 33 are the first.
It communicates with the oil chamber 25.

When the striking piston 4 returns, when the first pressure receiving surface 7 of the grooves set to communicate with the first oil chamber 25 by the signal pressure Pv first communicates with the first pressure chamber 9, high pressure Acts on the first oil chamber 25 to change the movement direction of the striking piston 4, so that the striking piston 4 at that time is selected by the groove having the shortest stroke among the grooves set to communicate with the first oil chamber 25. Stroke is determined. For example, when the signal pressure Pv is Pv> Pa, the shortest stroke S ₁ is
When Pa>Pv> Pb, the second shortest stroke S ₂ ,
The stroke S ₃ when the Pb>Pv> Pc.

When the signal pressure Pv is less than or equal to Pc or no signal is sent, the striking piston strikes with a stroke S determined by the first annular groove 14.

〔effect〕

According to the present invention, the opening / closing valve portion of the stroke control valve can reliably switch between opening and closing by the signal pressure and the spring force.
Each groove, that is, between the additional reciprocating reversal position detecting means and the control valve can be individually and reliably controlled to be opened and closed. The opening / closing valve section of the stroke control valve is controlled only by the spring force and the signal pressure, and the pressure fluctuation leading to the control valve does not act as the switching force of the opening / closing valve section, which enables highly reliable stroke adjustment.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a hydraulic breaker according to the present invention. 1 …… hydraulic breaker 2 …… cylinder 3 …… chisel 4 …… striking piston 5 …… control valve 6 …… stroke adjusting device 12 …… high pressure source, 14 …… reciprocating reversal position detecting means 18 …… low pressure Lines 31, 32, 33 ... Additional reciprocating reversal position detection means 34 ... Stroke control valves 34a, 34b, 34c ... Valve section

Claims (1)

[Claims] 1. A striking piston that reciprocates in a cylinder by hydraulic pressure, and the control valve is switched by switching the hydraulic pressure of the reciprocating reversal position detecting means of the striking piston to change the reciprocating direction of the striking piston. In a hydraulic breaker which performs reciprocating reversal switching by switching at least one of the working pressures to high or low, a plurality of additional reciprocating reversal position detecting means are provided, and the additional reciprocating reversal position detecting means are individually provided in the stroke control valves. A reciprocating motion reversal position of a striking piston for switching the control valve is adjusted by connecting to the control valve through one of a plurality of operating on-off valve parts and switching the on-off valve by a remote signal. And hydraulic breaker.