JPH0451991Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention relates to a reciprocating impact mechanism of a crusher equipped with tools such as a chisel, which is used in civil engineering construction such as road construction, building demolition, stone crushing, rock excavation, etc. be.

[Conventional technology]

The reciprocating mechanism of conventional hydraulic impact devices has upper and lower hydraulic chambers above and below the piston, so that high pressure always acts on the lower hydraulic chamber of the piston, and the upper hydraulic chamber drains oil during the upward stroke. Hydraulic pressure was controlled by a control valve so that the pressure became low during the impact stroke, and oil drainage stopped during the impact stroke, resulting in high pressure.

[Problem that the invention attempts to solve]

Conventional hydraulic impact devices have the disadvantage that large pulsations occur on the oil drain pipe side, which has a negative effect on the hydraulic pipes and oil pressure generators, shortens the life of mechanical parts, and in some cases damages the pipes and equipment. It was hot. As a means to suppress such pulsation, a pressure accumulator is installed in the main body of the device or in the conduit, but
Pressure accumulators are expensive, have a short lifespan, require maintenance and inspection, and have the problem of increasing production costs. The present invention aims to provide a practical hydraulic impact device that solves these problems.

[Means for solving problems]

The main structure of the present invention that solves these problems is to form an upper hydraulic chamber and a lower hydraulic chamber above and below the striking piston, so that high pressure always acts on the lower hydraulic chamber, and a piston is installed in the upper hydraulic chamber. In a hydraulic impact device that reciprocates the impact piston by controlling hydraulic pressure so that oil is drained and low pressure is applied during the upward stroke and high pressure is applied during the impact stroke, the upper part is lower than the lower part on the large diameter part of the impact piston. A configuration in which two stepped portions having a large outer diameter are provided, and an intermediate oil chamber formed between the two stepped portions and the inner wall of the piston cylinder is connected to an oil drain path of an upper oil chamber during the upward stroke of the striking piston. A hydraulic impact device is characterized by:

[Effect]

In the present invention, during the upward stroke of the percussion piston, a part of the waste oil from the upper hydraulic chamber is introduced into the intermediate oil chamber formed in the middle of the percussion piston and stored therein. During this upward stroke, the outer diameter of the upper step, which is the chamber wall, of the intermediate oil chamber is larger than the outer diameter of the lower step, so as the piston rises, the volume of the intermediate oil chamber increases, sucking in waste oil. Can be stored. Next, in the impact stroke, the volume of the intermediate oil chamber decreases, and the oil in the intermediate oil chamber is discharged, minimizing pulsation to the oil drain conduit.

〔Example〕

In the crusher of the embodiment shown in FIGS. 1 to 3, the outer diameter of the impact piston is d ₁ , d ₂ , d ₃ , d ₄ from the impact point side, and d ₃ > d ₂ > d With the relationship ₁ > d ₄ , an upper hydraulic chamber is formed at the outer diameter of d ₄ , and a lower hydraulic chamber is formed at the outer diameter of d ₁ , and the control valve moves according to the movement of the striking piston. The hydraulic path is automatically switched.

In the figure, Fig. 1 is an explanatory diagram showing the flow of hydraulic pressure at the start of the upward stroke of this embodiment, Fig. 2 is an explanatory diagram showing the flow of hydraulic pressure at the start of the striking stroke, and Fig. 3 is an explanatory diagram showing the flow of hydraulic pressure at the moment of striking. FIG. In the figure, 1 is a striking piston, 2 is an upper hydraulic chamber, 3 is a lower hydraulic chamber, 4
is a stepped portion with outer diameter d ₃ , 5 is a stepped portion with outer diameter d ₂ , 6 is an intermediate oil chamber, 7 is a piston cylinder, 8 is a control valve, 9 is a chisel, 10 is a high pressure accumulator, 11 is a high pressure oil path , 12 is an oil drain path, 13 is a communication path connecting the oil drain path and the intermediate oil chamber 6, and 14 is a cushion chamber.

In this embodiment, the flow of hydraulic pressure and the state of the control valve 8 during the upward stroke are shown in FIG. At this time, the oil in the upper hydraulic chamber 2 passes through the upper chamber of the control valve 8 and is discharged from the oil drain path 12, and a portion of the oil flows into the intermediate oil chamber 6 through the communication path 13. When the striking piston 1 rises and reaches the top dead center, the hydraulic pressure flow and the control valve 8 change to the state shown in FIG. 2. At this time, the pressure in the upper hydraulic chamber 2 is high, and the impact piston 1 is pressed downward due to the difference in pressure acting area with the lower hydraulic chamber 3 and moves downward. At this time, the volume of the intermediate oil chamber 6 decreases as it descends, and the oil is instead sent to the oil drain path 12. The striking moment of the striking piston 1 is shown in FIG. In this way, the oil pressure in the oil drain path 12 is averaged by the oil stored in the intermediate oil chamber 6 and the oil drained, and pulsation is greatly reduced.

[Effect of idea]

As described above, according to the present invention, by adopting the structure having the above characteristics, it is possible to greatly suppress the pulsation of the hydraulic pressure in the oil drain passage, thereby reducing damage to the hydraulic pressure generating device and the oil conduit, and increasing the oil pressure. It made it possible to extend the lifespan. Furthermore, since there is no need to use an expensive pressure accumulator, the manufacturing cost is low and there is no need for maintenance.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the state of the embodiment of the hydraulic impact device of the present invention at the start of the upward stroke, FIG. 2 is an explanatory diagram showing the state at the start of the same impact stroke, and FIG. 3 is the state at the same time of impact. FIG. 1...Blow piston, 2...Upper hydraulic chamber, 3...
... lower hydraulic chamber, 4, 5 ... step, 6 ... intermediate oil chamber, 7 ... piston cylinder, 8 ... control valve, 9 ... chisel, 11 ... high pressure oil passage,
12...Drainage path, 13...Communication path.

Claims (1)

[Scope of utility model registration request] An upper hydraulic chamber and a lower hydraulic chamber are formed above and below the striking piston, so that high pressure always acts on the lower hydraulic chamber, and oil is drained into the upper hydraulic chamber during the piston's upward stroke to reduce the pressure to low pressure. In a hydraulic impact device that reciprocates a striking piston by controlling hydraulic pressure so that high pressure is applied during stroke, two steps are provided in the middle of the large diameter part of the striking piston, the upper part having a larger outer diameter than the lower part. A hydraulic percussion device characterized in that an intermediate oil chamber formed between the two stepped portions and the inner wall of the piston cylinder is connected to an oil drain passage of an upper oil chamber during the upward stroke of the percussion piston.