KR20100039036A - Hydraulic breaker - Google Patents

Abstract

PURPOSE: A hydraulic breaker is provided to prevent a valve from rising until a piston hits on a chisel by preventing a lowering of pressure in a valve conversion chamber due to oil leakage of oil in the valve conversion chamber and increasing the efficiency. CONSTITUTION: A hydraulic breaker comprises a cylinder(11), a piston(P), a chisel(13), and a valve. The cylinder is made of breaker bodies. The piston is installed on the cylinder. The chisel is installed on the lower part of the cylinder to be hit by the piston. The valve reciprocates the piston by selectively supplying hydraulic oil to a lower cylinder room(11b) and an upper cylinder room(11a).

Description

Hydraulic Breaker {HYDRAULIC BREAKER}

The present invention relates to a hydraulic breaker mounted on heavy equipment such as an excavator and driven hydraulically, and more particularly, to a valve loss connected to a low pressure passage in an upper portion of a valve switching chamber, and to a low pressure passage in a piston rising in a lower portion of a valve switching chamber. And a cylinder upper chamber communicating with the high pressure flow passage when the piston descends, the valve switching chamber communicates with the high pressure flow passage so that the valve starts to descend and flows from the cylinder loss to the valve switching chamber when the valve is lowered by a certain distance. By forming an orifice to be supplied to prevent pressure drop in the valve switching chamber, the hydraulic breaker prevents the valve from rising until the piston hits the chisel while minimizing the drop in efficiency of the hydraulic breaker.

Hydraulic breaker is a device that crushes the crushed energy by converting the kinetic energy generated during the reciprocating motion of the piston to the impact energy as the piston strikes the chisel and transfers the impact energy to the crushed material such as rock or concrete that is in contact with the chisel end. It is connected to the hydraulic power source of the excavator is operated by receiving the hydraulic oil from the excavator.

When the hydraulic breaker is largely divided, the cylinder constituting the breaker body, a piston movably installed in the cylinder, a chisel installed under the cylinder so as to be hit by the piston, and selectively supply pressure oil to the cylinder chamber and the cylinder chamber And a valve which is a means for reciprocating the piston.

The piston is driven by hydraulic pressure to reciprocate between the top dead center and the bottom dead center, and is configured to strike the chisel at the bottom dead center. The chisel converts the kinetic energy of the piston into impact energy and transmits it to the crushed object. When the piston descends from the top dead center to the bottom dead center, the piston is hit by the piston.

And the valve, as shown in Japanese Patent Application Laid-open No. Hei 9-57649 and 12 to 20, the valve switching pressure surface (V4) for the valve down stroke is the valve high pressure pressure surface ( Located lower than V3), both the valve low pressure chamber 14e and the valve compartment 14b above and below the valve switching chamber 14c communicate with the low pressure passage 4.

In the hydraulic breaker, as shown in FIG. 12, nitrogen gas or the like is injected into the gas chamber 15 formed in the back head 10 of the piston upper end PU, and the chisel 13 is provided at the lower end of the piston P. FIG. ) Is mounted coaxially with the central axis of the piston P. When the hydraulic breaker is in the operating standby state, the piston P is pressed downward by the gas pressure in the gas chamber 15 such that the piston P is at the bottom dead center contacting the chisel 13, and the valve (14) is also in the lowered state by its own weight.

In addition, the hydraulic breaker of the piston lower hydraulic pressure surface PLA and the piston P, which is the lower surface of the lower large diameter portion P1 of the piston P, is supplied through the high pressure flow passage 1 when the hydraulic oil is supplied to the inlet. It is supplied to the cylinder compartment 11b formed between the lower large diameter part P1 and the cylinder 11, and at the same time through the high pressure flow path 1a, as shown in FIG. 12 and FIG. 16, the valve high pressure hydraulic surface V3. In this case, the high pressure always acts, and the upper and lower end surfaces of the valve 14 communicate with the low pressure passage 4 so that the low pressure always acts.

At this time, the valve switching chamber 14c communicates with the low pressure flow passage 4 via the valve switching chamber orifice 14d, the switching chamber flow path 8, and the cylinder switching chamber 11c, so that a low pressure acts on the valve switching hydraulic pressure surface V4. The valve 14 is raised. As a result, the cylinder upper chamber 11a is blocked from the high pressure passage 1a as shown in FIG. 12, and at the same time, the cylinder upper chamber 11a communicates with the low pressure passage 4 via the cylinder bush orifice 11f and the valve low pressure chamber orifice 14f. Low pressure is applied.

Therefore, the pressure of the cylinder compartment 11b is increased by the high-pressure working oil supplied to the cylinder compartment 11b, and the upward force acting on the piston lower hydraulic pressure surface PLA is lower than the downward force acting on the piston in the gas chamber 15. When the piston P starts to rise, the piston P starts to rise to the top dead center, and at the same time, the gas in the gas compression chamber 15 is compressed to increase the gas pressure.

At this time, as shown in FIG. 13, the hydraulic oil supplied to the cylinder compartment 11b at the same time as the top dead center of the piston P reaches the cylinder switching chamber 11c, the switching chamber flow path 8, and the valve switching chamber orifice 14d. It is supplied to the valve switching chamber 14c via the via. Thus, the high pressure is applied to the valve switching chamber 14c.

At this time, the area of the valve high pressure surface (V3) and the valve switching pressure surface (V4) has a relationship of V3 <V4, and therefore high pressure is simultaneously applied to the valve high pressure surface (V3) and the valve switching pressure surface (V4). When acting, the downward force is greater than the upward force acting on the valve 14, as shown in FIG. 14, the valve 14 is lowered.

When the valve 14 is lowered, as shown in FIGS. 14 and 18, the upper cylinder 11a is disconnected from the low pressure passage 4 through the cylinder bush orifice 11f and the valve low pressure chamber orifice 14f. At the same time, the valve high pressure orifice 14g and the cylinder bush orifice 11f communicate with the high pressure flow path 1a to act on the cylinder chamber 11a.

At this time, the relationship between PLA <PUA between the hydraulic pressure surface PUA and PLA on the piston P and the lower end thereof, so that the downward force is greater than the upward force acting on the piston P, so that the piston P Descent exercise.

When the piston P is lowered, the downward force by the compressed gas in the gas chamber 15 is added and descends at a much higher speed than when the piston P is raised, and the chisel located coaxially with the central axis of the piston P ( 13) hit the top surface.

Thus, by transmitting high-speed impact energy to a solid ground or rock that is in contact with the tip of the chisel 13, the rock or the like is broken.

When the lowering of the piston P is completed, as shown in Fig. 15, the valve switching chamber 14c passes through the valve switching chamber orifice 14d, the switching chamber flow passage 8 and the cylinder switching chamber 11c, and the low pressure flow passage 4 In communication with the low pressure.

Therefore, since the downward force acting on the valve 14 becomes smaller than the upward force, the valve 14 is raised, and the upward and downward operating cycles of the piston P mentioned above are 'valve rise' → 'piston rise' → It operates cyclically in order of 'valve lower' → 'piston lower'.

The hydraulic breaker is provided with a valve 14 and a plurality of flow paths in addition to the piston P for the vertical movement of the piston P generating the impact energy in the chisel 13.

According to the position of the piston (P) and the valve 14, by selectively connecting the flow path to the inlet or outlet to the high or low pressure state, the piston (P) and the valve 14 is configured to repeat the movement sequentially sequentially do.

The hydraulic breaker operation starts at the temperature of the hydraulic oil at first, but if it continues, the piston P and the valve 14 slide, the friction generated when the hydraulic oil flows along the pipe of the excavator, etc. As a result, the temperature of the working oil becomes very high.

In general, when two or more objects, for example, the piston P, the valve 14, and the cylinder bushing 11e, as shown in Figs. 12 to 19, there is a gap between the sliding surfaces. Leakage from the gap increases with increasing temperature, larger gap, shorter sliding surface, and larger diameter.

12 to 19, the valve 14 is configured to be large enough to be located outward than the piston (P), in general, the larger the diameter of the object to slide for smooth sliding, the larger the gap.

Therefore, when the valve 14 and the cylinder bush 11e slide, the leakage amount increases in the inner and outer diameters of the valve 14, and the valve low pressure chamber 14e in the upper portion of the valve switching chamber 14c and the valve compartment 14b in the lower portion thereof. Since both of them communicate with the low pressure passage 4 and always operate with low pressure, the amount of leakage leaking from the valve switching chamber 14c into the low pressure passage 4 also increases.

When the hydraulic breaker operation continues and the working oil reaches a very high temperature of 80 ° C. or more, as shown in FIG. 19, when the piston P moves downward, the piston is lowered while the piston P descends. When the upper surface of the minor diameter portion P1 passes the cylinder low pressure chamber 11d, the sliding surface formed with the inner circumferential surface between the lower large diameter portion P1 of the piston and the cylinder low pressure chamber 11d and the cylinder switching chamber 11c becomes very short. The amount of leakage from the switching chamber flow path 8 to the cylinder low pressure chamber 11d in communication with the low pressure flow path 4 increases.

This means that the operating oil of the valve switching chamber 14c in communication with the switching chamber flow path 8 flows out into the low pressure flow path 4 due to leakage, which causes a pressure drop in the valve switching chamber 14c.

In addition, since the hydraulic oil is in a high temperature state, the amount of leakage from the valve switching chamber 14c to the valve low pressure chamber 14f and the valve compartment 14b communicating with the low pressure passage 4 above and below the valve switching chamber 14c is also very large. This also causes a pressure drop in the valve switching chamber 14c. As a result, when the pressure in the valve switching chamber 14c becomes very low due to such leakage, the valve 14 may rise without maintaining the lowered state.

If the valve 14 is raised before the piston P hits the chisel 13, the opening area of the valve high pressure orifice 14g communicating the upper cylinder 11a from the high pressure flow passage 1a becomes small. As a result, the hydraulic oil supplied from the high pressure passage 1a to the upper cylinder 11a becomes relatively smaller than when the valve 14 is completely lowered.

This eventually leads to a pressure drop of the upper cylinder 11a, thus preventing the piston P from maintaining a sufficient dropping speed, thereby reducing the impact energy transmitted to the chisel 13.

In addition, the pressure drop in the valve switching chamber 14c proceeds at a very high speed, and the valve 14 rises very much before the piston P hits the chisel 13, causing the valve high pressure orifice 14g to be closed, thereby providing a high pressure flow path. The cylinder upper chamber 11a is disconnected from (1a). At this time, since the piston P continues to descend by inertia and the hydraulic oil is constantly supplied to the cylinder chamber 11b, the cylinder chamber 11b is the piston P. There is a problem that the phenomenon caused by compression.

In addition, due to the pressure rise of the cylinder compartment 11b, the descending speed of the piston P may be drastically reduced, and thus the piston P may not be able to hit the chisel 13. In addition, if a pressure reversal phenomenon occurs in which the pressure rise of the cylinder compartment 11b is excessive and becomes higher than the pump pressure of an excavator supplying hydraulic fluid, it causes an impact on the pump, and when such an impact accumulates, serious damage to the equipment such as an excavator is caused. There is a problem that can be given.

In order to prevent such an early rise of the valve 14, D9 is made smaller than the inner diameter D6 of the valve 14 in FIG. 16 so that the high pressure flow passage 1a and the cylinder upper chamber 11a communicate with each other even if the valve 14 is lowered. When the high pressure is applied to the valve inner hydraulic pressure surface (V5) may prevent the valve 14 from rising until the piston (P) hits the chisel (13).

However, since the valve 14 inner diameter is larger than the piston large diameter, that is, the area of the valve inner pressure receiving surface V5 is never a small area, it should be used to increase the piston P lowering speed when the piston P is lowered. There is a problem that the flow rate to be used is excessively used to delay the rise of the valve 14.

When an excessive flow rate is used to delay the rise of the valve 14, the descending speed of the piston P is reduced, which lowers the efficiency of the hydraulic breaker.

In addition, when the temperature of the hydraulic oil reaches a very high temperature of 80 ° C. or more, as the piston P rises toward the top dead center, the lower surface of the piston lower diameter portion P1 becomes closer to the cylinder switching chamber 11c. , The sliding surface formed between the inner circumferential surface between the cylinder compartment 11b and the cylinder switching chamber 11c and the piston lower diameter portion P1 becomes shorter and shorter.

Therefore, the amount of oil leakage from the cylinder compartment 11b to the cylinder switching chamber 11c increases through the assembly gap between the piston lower diameter portion P1 and the cylinder 11.

When the flow rate generated by this leakage flows into the valve switching chamber 14c via the switching chamber flow path 8 and fails to discharge the flow rate to the low pressure flow path 4 properly, the valve (1) increases due to the pressure rise in the valve switching chamber 14c. The downward force acting on 14) increases, so that the lower surface of the piston lower diameter portion P1 rises to the cylinder changeover chamber 11c, so that the valve compartment 11b and the cylinder changeover chamber 11c cannot communicate with each other. Will descend.

At this time, if the valve 14 is sufficiently lowered, the piston (P) hits the chisel 13 by a normal downward motion, but the pressure rise of the valve switching chamber 14c due to the flow rate due to such leakage causes the valve 14 to be sufficiently lowered. It is not enough to descend. Therefore, the lowering movement of the piston P is started in a state where the valve 14 is not completely lowered.

If the valve 14 does not descend completely, the opening of the valve high pressure orifice 14g communicating relatively with the high pressure flow passage 1a and the upper cylinder 11a as compared with the case where the valve 14 is lowered completely. The area becomes small. Therefore, since a sufficient flow rate from the high pressure flow passage 1a to the cylinder upper chamber 11a is not supplied during the piston P descending movement, the impact force is lowered.

In addition, when the valve is not sufficiently lowered to supply even the flow rate required for the downward movement of the piston, there is a problem that the phenomenon of stopping the operation of the hydraulic breaker may also appear, that is, do not do the downward movement in the stopped state of the piston. .

In addition, in FIG. 20, the path | route which the hydraulic fluid flows into from the high pressure flow path 1a to the valve 14 at the moment when the valve 14 descends is briefly shown. At a very short moment when the valve 14 descends, when the high pressure flow passage (1, 1a) enters the valve high pressure orifice (14g), the portion connected to the high pressure flow passage (1a) is operated with high pressure, but the opposite side to the connection with the high pressure flow passage (1a) Relatively lower pressure than the connection. Therefore, until the high pressure hydraulic fluid is supplied to the opposite side of the connection with the high pressure flow passage 1a, the valve 14 is momentarily lowered from the connection portion with the high pressure flow passage 1a to the opposite side to the connection portion with the high pressure flow passage 1a. Pushed.

Metal-to-metal contact between the valve 14 and the cylinder 11, or between the valve 14 and the cylinder bush 11e by temporarily pushing the valve 14 with a very large force generated by the above-mentioned high pressure hydraulic oil. There is a problem that may occur to cause scratches.

The above scratches are the biggest cause of abnormal operation of the hydraulic breaker.

The present invention has been proposed in order to solve the above problems of the prior art, an object of the present invention, when the piston is lowered and the piston moves downward, supplying a small amount of high pressure hydraulic fluid to the valve switching chamber to the oil leakage of the valve switching chamber By preventing the pressure drop of the valve switching chamber caused by the pressure, the valve is not raised until the piston hits the chisel to increase the efficiency of the hydraulic breaker.

Another object of the present invention, when the piston rises and the piston moves up, by effectively draining the flow rate flowing into the valve switching chamber due to the oil leakage to the low pressure flow path to prevent the pressure rise in the valve switching chamber, to improve the efficiency of the hydraulic breaker The valve is not lowered until the piston reaches the top dead center.

Another object of the present invention is to prevent the contact between the metal by preventing the valve from being pushed to one side by forming the flow path flowing from the high pressure flow path to the cylinder chamber at the moment when the valve descends for the downward movement of the piston. have.

Hydraulic breaker of the present invention for achieving this object, the cylinder forming the breaker body, the back head having a gas chamber on the cylinder and the piston movably installed in the cylinder, and is installed in the lower cylinder to be hit by the piston A chisel, a valve for selectively supplying pressure oil to the cylinder chamber and the upper cylinder chamber to reciprocate the piston, and a valve high pressure orifice and a valve low pressure chamber orifice for communicating the cylinder loss to the high pressure flow passage and the low pressure flow passage, respectively. In the hydraulic breaker to allow the cylinder loss is selectively communicated with the high pressure and low pressure flow path by the rising and falling of the valve, the valve switching pressure surface (V2) formed in the valve switching chamber in which the high pressure and low pressure selectively act on the valve; The valve high pressure hydraulic pressure surface (V1) at which the high pressure is always applied is set so that the pressure area V1 <V2. Low pressure and high pressure act on the valve switching chamber so that when the valve switching chamber communicates with the cylinder low pressure chamber, when the low pressure is formed on the valve switching pressure surface, the valve rises and when the high pressure is formed, the valve lowers; The upper portion of the valve is formed at the lower pressure at all times, and the upper and lower cylinders formed between the cylinder bush and the valve, the cylinder bush and the piston so that the low pressure and high pressure acts upon the lifting of the valve is characterized in that the lower portion of the valve switching chamber.

The valve is characterized in that the oil discharge orifice is formed to communicate with the valve upper chamber and the valve switching chamber in a state where the valve is raised above a certain height, and to prevent the valve chamber and the valve switching chamber from communicating when the valve is not raised above a certain height. .

The cylinder bush is provided with a lowering orifice for communicating the valve switching chamber and the cylinder upper chamber while the valve is lowered by a predetermined distance or more so as not to communicate the valve switching chamber and the cylinder upper chamber when the valve is lifted by a predetermined distance. do.

In the cylinder, when the valve is lowered for the piston lowering movement, the flow path flowing from the high pressure flow passage to the cylinder loss is formed to be symmetrical with each other so that the valve is not pushed to one side by the high pressure hydraulic oil flowing into the cylinder loss. do.

According to the present invention, when the piston descends and the piston moves downward, a small amount of high pressure hydraulic fluid is supplied to the valve switching chamber to prevent the pressure drop in the valve switching chamber due to leakage of the valve switching chamber until the piston strikes the chisel. By preventing the valve from rising, there is an effect of not lowering the efficiency of the hydraulic breaker.

In addition, when the piston rises and the piston moves up, the flow rate flowing into the valve switching chamber due to leakage is effectively discharged to the low pressure flow path to prevent the pressure rise in the valve switching chamber, so that the valve falls until the piston reaches the top dead center. There is an effect that does not lower the efficiency of the hydraulic breaker.

In addition, by locating the flow paths flowing from the high pressure flow path to the cylinder loss at the moment when the valve descends for the downward movement of the piston, the valves are not pushed to one side, thereby preventing abnormal operation of the hydraulic breaker. .

Hereinafter, a preferred embodiment of the present invention will be described in more detail with reference to the accompanying drawings (the same components as in the prior art are given the same reference numerals).

As shown in FIG. 1, the hydraulic breaker according to the present invention may be hit by a cylinder 11 constituting the breaker body, a piston P movably installed in the cylinder 11, and a piston P. A chisel 13 installed below the cylinder 11 and a valve 14 for reciprocating the piston P by selectively supplying pressure oil to the cylinder compartment 11b and the cylinder upper chamber 11a.

1 to 8, nitrogen gas or the like is injected into the gas chamber 15 formed in the back head 10 of the piston upper end PU, and the chisel 13 is the piston P as shown in FIGS. 1 to 8. The piston P is pushed downward by the gas pressure in the gas chamber 15 when it is in the operating standby state on the coaxial line with the center axis of the piston bottom, and the piston lower end PL is at the bottom dead center where the chisel 13 is in contact with the chisel 13. The valve 14 is also in the lowered state due to its own weight.

However, as shown in FIG. 1, when the hydraulic breaker is operated to supply high pressure hydraulic fluid to the inlet, the piston lower pressure surface, which is the lower surface of the lower large diameter portion P1 of the piston P, is supplied through the high pressure flow passage 1 ( It is supplied to the cylinder base (11b) formed between PLA) and the lower large diameter portion (P1) of the piston and the cylinder, and at the same time through the high-pressure flow path (1a), as shown in Figs. High pressure always acts on V1), and the upper and lower end surfaces of the valve 14 communicate with the low pressure passage 4 so that the low pressure always acts.

At this time, the valve switching chamber 14c communicates with the low pressure passage 4 via the valve switching chamber orifice 14d, the switching chamber flow passage 3, and the cylinder switching chamber 11c, so that a low pressure acts on the valve switching hydraulic pressure surface V2. The valve 14 is raised. As a result, the cylinder upper chamber 11a is blocked from the high pressure passage 1a as shown in FIG. 7, and at the same time, the cylinder upper chamber 11a communicates with the low pressure passage 4 via the cylinder bush orifice 11f and the valve low pressure chamber orifice 14f. Low pressure is applied.

Therefore, the pressure of the cylinder compartment 11b is increased by the high-pressure working oil supplied to the cylinder compartment 11b, and the upward force acting on the piston lower pressure receiving surface PLA acts on the piston P in the gas chamber 15. When greater than the downward force, the piston P starts to rise and rises to the top dead center, and at the same time, the gas in the gas chamber 15 is compressed to increase the gas pressure. At this time, as shown in Fig. 2, the hydraulic oil supplied to the cylinder compartment 11b at the same time as the top dead center of the piston P reaches the cylinder switching chamber 11c, the switching chamber passage 3, and the valve switching chamber orifice 14d. The valve switching chamber 14c is supplied to the valve switching chamber 14c so that a high pressure acts on the valve switching chamber 14c.

At this time, since the area of the valve high pressure pressure surface (V1) and the valve switching pressure surface (V2) has a relationship of V1 <V2, if the high pressure is applied to the valve high pressure pressure surface (V1) and the valve switching pressure surface (V2) at the same time The downward force is greater than the upward force acting on the valve 14, so that the valve 14 is lowered as shown in FIG.

When the valve 14 is lowered, as shown in Figs. 3 and 8, the upper cylinder 11a is disconnected from the low pressure passage 4 through the cylinder bush orifice 11f and the valve low pressure chamber orifice 14f. At the same time, the high pressure flow passage 1a communicates with the high pressure flow passage 1a through the valve high pressure orifice 14g and the cylinder bush orifice 11f, and the high pressure acts on the cylinder upper chamber 11a.

At this time, the relationship between PLA <PUA between the hydraulic pressure surface PUA and PLA on the piston P and the lower end thereof, so that the downward force is greater than the upward force acting on the piston P, so that the piston P Descent exercise.

When the piston P descends, the downward force by the compressed gas in the gas chamber 15 is added, and the piston descends at a much faster speed than the piston P ascends, and the chisel located coaxially with the central axis of the piston P ( 13) hit the top surface. For this reason, by transmitting high-speed impact energy to the solid ground or rock which is in contact with the line end of the chisel 13, the rock or the like is crushed.

When the lowering of the piston P is completed, as shown in Fig. 4, the valve switching chamber 14c passes through the valve switching chamber orifice 14d, the switching chamber flow passage 3, and the cylinder switching chamber 11c. The low pressure acts in communication with 4) and the downward force acting on the valve 14 becomes smaller than the upward force, so that the valve 14 is raised. The above-mentioned operation of raising and lowering the piston P is operated by repeating the circulation in the order of 'valve rising' → 'piston rising' → 'valve falling' → 'piston falling'.

In such a hydraulic breaker, the valve 14 and a plurality of flow paths are formed in addition to the piston P for the up-and-down repetitive movement of the piston P generating the impact energy to the chisel 13.

Depending on the position of the piston P and the valve 14 described above, the flow path is selectively connected to the inlet or outlet to be switched to a high or low pressure state. Accordingly, the piston P and the valve 14 are configured to sequentially repeat each other.

When the hydraulic breaker operation continues and the hydraulic oil reaches a very high temperature of 80 ° C. or more, as shown in FIG. 4, when the piston P moves downward, the piston P descends. When the upper surface of the lower large diameter portion P1 passes through the cylinder low pressure chamber 11d, the sliding surface formed with the inner circumferential surface between the lower large diameter portion P1 of the piston and the cylinder low pressure chamber 11d and the cylinder switching chamber 11c becomes very short. Therefore, the amount of leakage from the switching chamber flow passage 3 to the cylinder low pressure chamber 11d communicating with the low pressure passage 4 increases. This means that the hydraulic oil of the valve switching chamber 14c in communication with the switching chamber flow passage 3 escapes to the low pressure flow passage 4 due to leakage of oil, which causes the pressure drop in the valve switching chamber 14c.

In addition, since the hydraulic oil is in a high temperature state, the amount of leakage from the valve switching chamber 14c to the valve upper chamber 14a communicating with the low pressure passage 4 on the upper portion of the valve switching chamber 14c also increases, which is also the valve switching chamber 14c. ) Will cause a pressure drop.

As a result, when the pressure in the valve switching chamber 14c becomes very low due to such leakage, the valve 14 may rise without maintaining the lowered state.

In order to prevent such a phenomenon, as shown in Figure 6, the falling holding orifice (6) is formed. As shown in FIG. 7, when the valve 14 is raised when the piston P is raised, the lowering orifice 6 is blocked by the inner diameter of the valve 14 so that the upper cylinder 14a and the valve switching chamber 14c. ) Do not communicate.

On the other hand, when the valve 14 is lowered to lower the piston (P) as shown in Figure 8, the cylinder upper chamber (11a) is in communication with the high-pressure flow path (1a) is applied high pressure, the constant shown in Figure 7 When the valve 14 is lowered by the distance M or more, the valve switching chamber 14d and the cylinder upper chamber 11a communicate with each other by the lowering orifice 6 until the valve switching chamber 14c is released from the high pressure cylinder upper chamber 11a. Flow rate is supplied.

By supplying the flow rate from the upper cylinder chamber 11a to the valve switching chamber 14c, the pressure drop in the valve switching chamber 14c is prevented by replenishing the flow rate leaving the valve switching chamber 14c due to leakage. The problem that the valve 14 is raised before hitting the chisel 13 can be solved.

The lowering orifice 6 has a valve switching chamber 14c only for a very short time while the upper surface of the large diameter portion P1 of the piston passes through the cylinder switching chamber 14c and the piston P strikes the chisel 13. In order to prevent the pressure drop of), the cross-sectional diameter is processed very small.

The cross-sectional diameter of the switching chamber flow path 3 which communicates the valve switching chamber 14c and the cylinder switching chamber 11c, and the cross-sectional diameter formed between the cylinder switching chamber 11c and the cylinder low pressure chamber 11d are the lowering orifice 6 Since the piston P strikes the chisel 13, the flow rate of the hydraulic oil in the valve switching chamber 14c through the cylinder switching chamber 11c and the cylinder low pressure chamber 11d to the low pressure passage 4 is increased. , It is much higher than the flow rate flowing through the orifice 6 for lowering and maintaining. Therefore, the situation where the valve switching chamber 14c continuously maintains the high pressure by the flow rate flowing through the lowering maintenance orifice 6 does not occur.

In addition, the flow rate flowing into the valve switching chamber 14c through the lowering maintenance orifice 6 is a very small amount because it supplements only the flow loss due to leakage. Therefore, this decreases the piston (P) lowering speed does not occur a situation that the efficiency of the hydraulic breaker is lowered.

9 and 10 show another embodiment of the lowering orifice 6. In FIGS. 5, 7, and 8, the lowering orifice 6 has a groove or a slot, but in FIG. 9 and FIG. 10, the lowering and maintaining hole is a very small through hole communicating the upper cylinder 11a and the valve switching chamber 14c. The orifice 6a is formed. However, when the high pressure acts on the valve switching chamber 14c and the valve 14 is lowered by a predetermined distance or more, the cylinder upper chamber 11a and the valve switching chamber 14c communicate with each other so that the high pressure is applied from the cylinder upper chamber 11a to the valve switching chamber 14c. When the hydraulic oil is supplied and the cylinder cylinder 11a does not communicate with the valve switching chamber 14c when it is raised by a certain distance, it functions the same. Therefore, only the processing methods and shapes of the grooves, slots, and through-holes are different. It serves as an orifice 6.

In the present invention, as shown in Figs. 5, 7, and 8, the oil discharge orifice 5 is formed in the valve 14.

When the temperature of the hydraulic oil is at a high temperature of 80 ° C. or higher, a high-pressure hydraulic oil is supplied to the cylinder compartment 11b so that the pressure in the cylinder compartment 11b increases, which causes the piston P to rise toward the top dead center. As the lower surface of the piston lower diameter portion P1 is closer to the cylinder switching chamber 11c, the sliding surface formed between the inner circumferential surface between the cylinder compartment 11b and the cylinder switching chamber 11c and the piston lower diameter portion P1 is gradually increasing. Will be shortened. As a result, the amount of leakage from the cylinder compartment 11b to the cylinder switching chamber 11c is increased through the assembly gap between the piston lower diameter portion P1 and the cylinder 11.

As shown in FIG. 7, even if the flow rate generated by the leakage oil flows into the valve switching chamber 14c via the switching chamber flow passage 3, the flow rate due to the leakage oil is lost through the leakage loss orifice 5. Since it is discharged to 14a) and discharged to the low pressure flow path 4 communicated with it, it is possible to prevent the rise of the valve 14 early by preventing the pressure rise of the valve switching chamber 14c. Therefore, it is possible to prevent the lowering of the impact force due to the oil leakage and the reduction of the efficiency of the hydraulic breaker.

11 is a schematic diagram showing that high pressure flow paths are formed on both sides of the valve shown in FIG. 1, and the valve 14 is connected to the high pressure flow path 1a and the high pressure flow path at positions opposite to each other through the cylinder compartment 11b. 1c) is in communication with each other so that high pressure is always applied.

Due to this, the very high pressure oil passage 1a and the high pressure oil passage 1c on the opposite side are supplied at the same time with the high pressure flow passage 1a at which the valve 14 descends. As a result, the valve 14 is not pushed to one side even when high pressure is momentarily applied. That is, the valve 14 can prevent the metal 11 from contacting the cylinder 11 or the cylinder bush 11e.

1 to 4 are hydraulic breakers according to the present invention, in which low pressure and high pressure are selectively acted on the valve switching chamber to show the operation of the hydraulic breaker in which the piston moves up and down as the valve moves up and down. .

FIG. 5 is a view of the valve shown in FIG. 1 showing an oil discharge orifice formed. FIG.

FIG. 6 is a view illustrating a descending orifice being formed with the cylinder bush shown in FIG. 1. FIG.

Fig. 7 shows the hydraulic oil discharged from the valve switching chamber to the low pressure flow path through the oil leakage discharge orifice of the valve shown in Fig. 5 when the valve shown in Fig. 1 is released from the cylinder loss through the lowering orifice of the cylinder bush shown in Fig. 6; A diagram showing that the supply of hydraulic oil to the valve changeover chamber is cut off.

FIG. 8 is a view showing a case where an early rise of the valve is prevented by the lowering orifice shown in FIG. 6; FIG.

9 and 10 show still another embodiment of the lowering orifice of the cylinder bush shown in FIGS. 6, 7, and 8;

FIG. 11 is a schematic view showing that high pressure flow paths are formed on both sides of the valve shown in FIG.

12 is a view showing a hydraulic breaker according to the prior art.

FIG. 13 is a view showing that the high pressure hydraulic oil passing through the cylinder chamber is acted on the valve switching chamber when the top dead center of the piston shown in FIG. 12 is reached; FIG.

FIG. 14 is a view showing that the valve shown in FIG. 12 is lowered to an area difference (V₃ <V₄) at high pressure. FIG.

FIG. 15 is a view showing that the valve switching chamber is interlocked with the low pressure flow path when the valve shown in FIG. 12 descends and the piston moves downward to strike the chisel.

FIG. 16 is a view showing the valve shown in FIG. 12; FIG.

FIG. 17 shows the cylinder bush orifice shown in FIG. 12 communicating with the valve low pressure chamber orifice, and the upper cylinder being in communication with the low pressure flow path.

FIG. 18 is a view showing lowering of the valve during sliding of the valve and the cylinder bush shown in FIG. 17. FIG.

FIG. 19 is a view showing that when the upper surface of the lower large diameter portion of the piston shown in FIG. 12 passes the cylinder low pressure chamber, the length of the sliding surface formed by the lower large diameter portion of the piston and the inner circumferential surface of the cylinder is shortened.

FIG. 20 is a schematic view for explaining the case where there is only one side of the high pressure flow path flowing into the valve shown in FIG. 12; FIG.

<Explanation of symbols for the main parts of the drawings>

V1, V3: Valve high pressure hydraulic surface V2, V4: Valve switch hydraulic pressure surface

V5: Valve inner hydraulic pressure surface P: Piston

1,1a, 2,2a: high pressure flow path 3: switching chamber flow path

4,9 low pressure flow path 11: cylinder

11a: cylinder loss 11b: cylinder base

11c: cylinder switching chamber 11d: cylinder low pressure chamber

12: Front Head 13: Chisel

14: Valve 14a: Valve missing

14b: valve compartment 14c: valve switching chamber

14d: valve switching chamber orifice 14e: valve low pressure chamber

14f: Valve low pressure chamber orifice 14g: Valve high pressure orifice

Claims (6)

A cylinder 11 constituting the breaker body, a back head 10 having a gas chamber 15 above the cylinder 11, a piston P movably mounted to the cylinder 11, and a piston P A chisel 13 installed under the cylinder 11 so as to be hit by the valve 11, a valve 14 for reciprocating the piston P by selectively supplying pressure oil to the cylinder compartment 11b and the cylinder upper chamber 11a; And a valve high pressure orifice (14g) and a valve low pressure chamber orifice (14f) which communicate the cylinder compartment (11b) with the valve (14) to the high pressure flow passage and communicate the cylinder upper chamber (11a) with the high pressure flow passage and the low pressure flow passage, respectively. In the hydraulic breaker to make the cylinder chamber (11a) selectively communicates with the low pressure flow path and the high pressure flow path by raising and lowering the valve 14, The valve switching hydraulic pressure surface V2 formed in the valve switching chamber 14c in which the high pressure and the low pressure selectively act on the valve 14 and the valve high pressure hydraulic pressure surface V1 at which the high pressure is constantly acted on the hydraulic pressure area V1 <V2. Form so that The low pressure and the high pressure are selectively acted on the valve switching chamber 14c, and when the low pressure is formed on the valve switching pressure surface V2, the valve 14 is raised, and when the high pressure is formed, the valve 14 is lowered. , The upper valve switching chamber 14c is formed between the cylinder bush 11e and the valve, the cylinder bush, and the piston so that the valve upper chamber 14a which is always low pressure is formed, and the low pressure and the high pressure act upon the lifting of the valve 14. Hydraulic breaker, characterized in that the upper cylinder (11a) is formed in the lower portion of the valve switching chamber (14c). The method of claim 1, In the valve 14, the valve upper chamber 14a and the valve switching chamber 14c communicate with each other in a state in which the valve 14 rises by a predetermined height or more, and the valve upper chamber 14a and the valve switching chamber ( Hydraulic breaker, characterized in that the oil discharge orifice (5) is formed so that the 14c) does not communicate. The method of claim 1, The cylinder bushing 11e communicates with the valve switching chamber 14c and the cylinder upper chamber 11a in a state where the valve 14 is lowered by a predetermined distance or more, and the valve switching chamber 14c when the valve 14 is raised by a predetermined distance. A hydraulic breaker, characterized in that the lowering orifice (6) is formed so as not to communicate with the cylinder upper chamber (11a). The method of claim 1, In the cylinder 11, when the valve 14 is lowered for the piston P lowering movement, the valve 11 is prevented from being pushed to one side by the high pressure hydraulic oil flowing into the cylinder upper chamber 11a. Hydraulic breaker, characterized in that the flow path (1, 1a, 2, 2a) flowing into the cylinder upper chamber (11a) is formed to be symmetrical to each other. The method of claim 2, The oil discharge orifice (5), the hydraulic breaker, characterized in that formed in any one of the groove or slot. The method of claim 3, wherein The lowering orifice (6) is a hydraulic breaker, characterized in that formed by any one of a groove, a slot or a through hole.

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