KR960004276B1 - Hydraulic brake - Google Patents

Abstract

The hydraulic breaker is for absorbing shock pressure generated by the strike of a piston, enhancing the strike force and speed, and utilizing the hydraulic energy stored when a valve device and a piston get elevated. It comprises a chisel(8) for striking a crushing object; a piston(2) hydraulically driven over the chisel(8); a valve housing(3) including a high pressure inlet(9), a lower pressure outlet(10), a high pressure chamber(16) of a valve, a lower pressure chamber(17) of the valve, and a valve conversion chamber(18); an accumulator(6); a high pressure fluid circuit(11) connected the high pressure chamber(16) of the valve to the lower pressure chamber(17); and a hole(20) formed in the valve(4) for connecting an inner chamber(19) of the valve selectively to the high pressure chamber(16) or the low pressure chamber(17).

Description

Hydraulic breaker

1 is a schematic structural diagram of a breaker without a conventional accumulator.

2 is a schematic structural diagram of a breaker with a conventional accumulator.

3 is a system diagram showing a hydraulic circuit used in the hydraulic breaker according to the present invention.

4 is a cross-sectional view showing the initial structure of the piston stroke stroke of the hydraulic breaker according to the invention.

FIG. 5 is a sectional view of a state following FIG. 4 showing a structure of a state in which valve switching starts. FIG.

FIG. 6 is a sectional view of a state following FIG. 5 showing the structure of a piston lowering stroke initial stage. FIG.

FIG. 7 is a cross-sectional view of the structure immediately following the piston strike, following FIG. 6; FIG.

* Explanation of symbols for main parts of the drawings

1: cylinder 2: piston

3: valve housing 4: valve

6: accumulator 7: cylinder gas seal

8: chisel 9: high pressure inlet

10: Low pressure outlet 11,11 ', 11 ": High pressure flow path

12: cylinder base 13: cylinder switching chamber

14 cylinder low pressure chamber 15 cylinder loss

16: valve high pressure chamber 16 ': accumulator side high pressure chamber

17: valve low pressure chamber 18: valve switching chamber

18 ': valve hydraulic chamber 19: valve chamber

20,20 ': Valve flow path hole 23,24: Valve hydraulic pressure surface

26: accumulator gas seal

The present invention relates to a hydraulic breaker that strikes with the force of the hydraulic pressure and the compression gas, in particular a valve mechanism and a piston for controlling the piston reciprocating motion to reduce the impact pressure generated during the piston strike and increase the piston blow speed to increase the impact force The hydraulic breaker provided with the accumulator device which makes use of the hydraulic energy accumulate | stored at the time of a piston descending.

So-called co-pneumatic breakers, operated by hydraulic and compressed gas forces, are generally devices that break hundreds of strikes per minute and repeatedly deliver large striking force to each rock. Therefore, until the rock is crushed, and each time a rebound movement caused by elasticity, the impact pressure is continuously generated in the breaker as much as the number of hits.

This impact pressure is transmitted to the high pressure side or the low pressure side flow path according to the breaker valve mechanism, resulting in damage to the hydraulic pump or other parts in the pipe and shortening of life.

The conventional hydraulic breaker uses a kind of three-port two-position valve as a valve mechanism for controlling the reciprocating motion of the piston. 1 and 2 show a schematic structure of a conventional breaker device. In Figs. 1 and 2, or Figs. 3 to 7 showing the structure according to the present invention, the same or similar parts are added with the same numerals. 1 and 2, as the valve 4 is raised or lowered, the valve inner chamber 19 in which the valve flow paths 20 and 20 'are connected to the upper cylinder 15 is connected to the valve high pressure chamber 16 or the valve. Alternatingly connected to the low pressure chamber 17, the high pressure and low pressure act alternately to the upper cylinder chamber (15).

The piston 2 rises by the high pressure which always acts on the cylinder chamber 12, and the high pressure acts on the valve switching chamber 18 through the cylinder switching chamber 13 before the piston reaches the top dead center, and the valve 4 Rises.

When the valve 4 rises, the flow path connected to the cylinder upper chamber 15, the valve inner chamber 19, the valve flow path holes 20 and 20 'and the valve low pressure chamber 17 is cut off, and the valve high pressure chamber 16, A high pressure flow path is formed to be connected to the valve flow path hole 20, the valve inner chamber 19, and the cylinder upper chamber 15 so that high pressure acts on both the upper and lower ends of the piston 2. Since the hydraulic pressure area of the upper end portion is larger than the hydraulic pressure area of the lower end portion, the piston 2 is lowered by the force of the high pressure and the compression gas of the cylinder gas chamber 7 acting on the area difference between the upper end and the lower end.

Since the lower large diameter part of the piston 2 is blocking the cylinder switching chamber 13 from the initial stage of lowering of the piston 2 to the middle stage, the valve switching chamber 18 continues to maintain the high pressure state, and the high pressure flow path connected to the cylinder upper chamber 15 is maintained. Figure also maintains the state of high pressure to supply the pressure oil required for the lowering of the piston (2).

When the piston 2 reaches the lower dead center, the piston lower large diameter portion is lowered below the cylinder switching chamber 13 and the blocked cylinder switching chamber 13 communicates with the cylinder low pressure chamber 14.

Therefore, the valve switching chamber 18 is switched to low pressure so that the valve 4 is lowered. The piston (2) hits the upper surface of the chisel (8) at the bottom dead center, and the mutual impact force is transmitted between the piston (2) and the chisel (8) and the rock to be crushed, and immediately after the blow due to their resilience The piston will rebound upward and bounce off. Therefore, the pressure rises instantaneously in the cylinder chamber 15, and the impact pressure is transmitted to the flow path and components connected to the periphery thereof.

In the conventional method, the flow path formed by the valve 4 is connected to one of the main high pressure flow path or the drain flow path according to the position of the valve flow path holes 20 and 20 '. The impact pressure is transmitted to the hydraulic pump through the main high pressure flow path or to the filter or cooling device of the low pressure flow path through the drainage flow path. Therefore, these parts, pipes and breakers are subjected to repeated loads due to the impact pressure, which causes parts damage and shortens the life.

On the other hand, in the conventional valve elevation, the large flow rate supplied to the cylinder upper chamber 15 is passed through one valve flow path through the valve flow path hole 20 in the piston lowering stroke, and the pressure loss according to the large flow rate is increased. To reduce this pressure loss, the diameter and stroke of the valve had to be increased in order to increase the flow path area formed by the valve flow path lifesaving 20. Therefore, the volume and weight of the valve and the valve housing are increased, and the flow rate and time required for raising and lowering the valve are increased, thereby reducing the efficiency of the breaker.

In the case of the breaker shown in FIG. 1, the accumulator is not used so that the impact pressure at the time of blow is transmitted to the outside of the breaker. The breaker of FIG. 2 has the accumulator 6, but the impact pressure is completely It is not absorbed and is delivered to the hydraulic pump through the valve high pressure chamber 16 and the high pressure inlet 9 or through the valve low pressure chamber 17 and the low pressure outlet 10 to the drain side component.

The present invention is a valve mechanism for controlling the piston reciprocating motion of the breaker by installing a kind of four-port three-position valve mechanism provided with a dedicated accumulator flow path to absorb the shock pressure generated when the piston strikes the accumulator to operate by the impact pressure and By reducing the damage of parts and supplying the large flow rate to the piston lower in two flow paths, the small size and small stroke valve minimizes the pressure loss caused by the large flow rate and increases the piston blow speed, thereby increasing the impact force of the breaker. Is to increase.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 shows a circuit diagram of a breaker according to a suitable embodiment of the present invention. The valve mechanism has four ports of the valve high pressure chamber 16, the accumulator side high pressure chamber 16 ', the valve low pressure chamber 17, and the valve inner chamber 19, and the valve hydraulic pressure chamber 18' and the valve switching chamber ( 18, the valve inner chamber 19 and the valve low pressure chamber 17 are connected by the valve 4 which slides in the valve housing 3 according to the applied pressure, and the valve inner chamber 19 and the accumulator side high pressure The connection of the chamber 16 ', the valve inner chamber and the accumulator-side high pressure chamber 16', and the valve high pressure chamber 16 can be sequentially performed.

Inside the cylinder 1, the piston 2 is installed to reciprocate up and down, and the upper end of the piston 2 is formed with a piston upper hydraulic pressure surface 21 to receive the pressure of the upper cylinder 15, the piston ( At the lower end of 2), a piston lower pressure receiving surface 22, which is pressurized by the cylinder base 12, is formed. The cylinder upper chamber 15 is connected to the valve inner chamber 19 so that the valve inner chamber 19 is changed into high pressure and low pressure according to the position of the valve 4 so that the cylinder upper chamber 15 also changes into high pressure and low pressure accordingly. , The cylinder base 12 is connected to the high pressure inlet (9) to maintain a high pressure at all times. The cylinder switching chamber 13 communicates with the cylinder base 12 in the vicinity of the bottom dead center of the piston 2 depending on the position of the piston 2 and operates like a kind of flip-flop circuit. The cylinder low pressure chamber 14 is connected to the low extrusion port 10 via the valve low pressure chamber 17 and is always at low pressure.

In the valve mechanism, the valve high pressure chamber 16 is connected to the high pressure inlet 9 and is always at high pressure, and the valve low pressure chamber 17 is connected to the low extrusion port 10 and is always at low pressure. The valve hydraulic pressure chamber 18 ′ is connected to the valve high pressure chamber 16 and thus always exerts a force on the valve hydraulic pressure surface 23 (see FIG. 4) that is subjected to the pressure because the pressure is high. The valve switching chamber 18 is connected to the cylinder switching chamber 13 so that the high pressure and the low pressure are alternately applied depending on the position of the fston 2, and the valve switching pressure surface 24 (see FIG. 4) is the valve pressure receiving surface 23. When the area becomes larger and the high pressure is applied to the valve switching chamber 18, the valve moves.

The high pressure chamber 16 'of the accumulator side of the valve mechanism is connected to the oil chamber of the accumulator 6 of the breaker so that the oil pressure in the accumulator can directly enter and exit, and the remaining flow path of the accumulator 6 is the cylinder base 12. Is connected to.

The operation of the present invention will be described using the cross-sectional views of FIGS.

4 is a structural diagram of a state in which the ascending stroke of the piston 2 is started as in the initial state before the breaker operation. The pressurized oil supplied to the high pressure inlet 9 of the breaker is supplied to the cylinder base 12 via the valve high pressure chamber 16 and the main pressure passage 11.

At this time, since the piston 2 is at the bottom dead center, the cylinder switching chamber 13 is connected to the cylinder low pressure chamber 14 and the valve switching chamber 18 is at low pressure, so that a small force is applied to the valve switching pressure receiving surface 24 while the valve hydraulic pressure is applied. Since the seal 18 'is connected to the valve high pressure chamber 16 and is always at high pressure, a force greater than the force acting on the valve switching pressure receiving surface 24 acts on the valve pressure receiving surface 23 so that the valve 4 is lowered. Will be maintained. Therefore, the valve inner chamber 19 is connected to the valve low pressure chamber 17 through the valve flow path hole 20 so that the cylinder upper chamber 15 is also subjected to low pressure.

The high pressure, which is normally applied to the cylinder base 12, exerts an upward force on the piston lower hydraulic pressure surface 22, so that the piston 2 overcomes its own weight and the friction generated between the inner wall of the cylinder 1 Begin the ascent. The pressure in the cylinder chamber 12 is gradually increased by the pressure of the gas acting on the upper end of the piston 2 and the back pressure generated as the fluid in the cylinder chamber 15 is pushed out to the low pressure outlet through the valve mechanism. The pressure of the oil chamber of the accumulator 6 connected with the pump 12 is gradually increased so that the accumulator gas chamber 26 is separated from the oil chamber by the diaphragm 25 of the accumulator 6. Compresses gradually, in equilibrium with pressure. Therefore, a part of the pressurized oil supplied through the high pressure inlet enters the oil chamber of the accumulator 6 through the cylinder base 12, and as the piston 2 rises closer to the top dead center, the rising speed thereof decreases. Through this process, the piston 2 ascends to the top dead center by compressing the accumulator gas chamber 26 and the cylinder gas chamber 7 only with pressure oil supplied to the high pressure inlet 9.

5 is a structural diagram of the end of the piston stroke stroke, showing the state at the time when the valve switching starts. When the piston 2 continuously rises and the piston lower pressure receiving surface 22 rises to the position of the cylinder switching chamber 13, the cylinder switching chamber 13 is connected to the cylinder base 12 through the cylinder inner wall and is converted to high pressure.

Therefore, a high pressure also acts on the valve switching chamber 18 and exerts an upward force on the valve switching hydraulic pressure surface 24. On the other hand, since the valve switching pressure receiving surface 24 has a larger area than the valve pressure receiving surface 23 and the valve pressure receiving chamber 18 'and the valve switching chamber 18 are subjected to the same high pressure, the force of the force acting on the valve 4 is The valve 4 rises in an upward direction. During this valve upstroke, the oil pressure is consumed by the volume multiplied by the valve stroke by the area difference between the valve switching hydraulic pressure surface 24 and the valve hydraulic pressure surface 23. Therefore, the oil consumption is extremely small and the oil pressure accumulated in the accumulator 6 is reduced. The loss is very small.

FIG. 6 shows a state at which the piston is turned down as the valve is raised and the flow path is changed after FIG. As described above, when the valve 4 rises, the position of the valve flow path hole 20 rises upward, thereby disconnecting the valve inner chamber 19 and the valve low pressure chamber 17, and the valve inner chamber 19 and the accumulator side high pressure. The hydraulic oil is supplied to the cylinder upper chamber 15 connected to the valve inner chamber 19 by connecting the chamber 16 '.

Subsequently, as the valve 4 is further raised, the valve flow hole 20 connects the valve inner chamber 19 and the valve high pressure chamber 16 to supply the pressure oil supplied to the high pressure inlet 9 to the valve high pressure chamber 16 and the valve inner chamber. It is supplied to the cylinder upper chamber 15 via (19).

Therefore, high pressure also acts on the piston upper hydraulic pressure surface 21, and since the piston upper hydraulic pressure surface 21 has a larger area than the piston lower hydraulic pressure surface 22, the piston 2 moves downward by the pressure acted by the area difference. The piston 2 is lowered at a high speed by adding the force of the piston and the weight of the piston to the force by the gas pressure of the cylinder gas chamber 7.

At this time, since the cylinder switching chamber 13 is blocked by the large diameter of the lower end of the piston while the piston 2 descends to the bottom dead center, the valve 4 maintains the elevated position while the valve switching chamber 18 is kept at a high pressure. .

When the piston (2) is lowered, the hydraulic oil is supplied to the cylinder upper chamber (15) and the hydraulic oil is discharged from the cylinder chamber (12), so that the flow rate as much as the piston lowering speed multiplied by the area difference between the upper and lower hydraulic pressure surface. In addition, the faster the piston descends, the more flow is required. Therefore, in order to increase the piston descending speed, the flow rate supplied to the breaker should be increased or the area difference between the upper and lower hydraulic pressure surfaces should be reduced. However, the supply flow rate is limited, and if the area difference between the upper and lower hydraulic pressure surfaces is reduced, it acts on the piston. The downward force becomes small so that a large acceleration cannot be obtained when the piston descends. An additional device installed to compensate for this problem is the accumulator. In the case of the conventional breaker, the breaker provided with the accumulator exerts a greater hitting force than when the accumulator is not installed. In addition, if the accumulator is not installed, the required flow rate increases as the piston's descending speed increases, while the pressure oil supplied to the breaker becomes constant, resulting in the main high pressure passage 11 of the breaker and the supply-side high pressure pipe connected thereto. The pressure of the lowering and the continuous high pressure is not applied to the cylinder chamber 15 is unable to obtain a high hitting speed. One of the important roles of the accumulator is to compensate for the shortage of the supply flow during the lowering stroke of the piston to compensate for the lower pressure of the cylinder chamber 15.

As shown in FIG. 6, when the piston 2 descends, a part of the pressurized oil discharged from the cylinder base 12 is introduced into the valve chamber 19 through the main high pressure passage 11, and the part of the pressurized oil is the high pressure passage 11. ') And the accumulator 6 enters the valve inner chamber 19 through the high pressure passage 11' and the accumulator-side high pressure chamber 16 'together with the supplementary flow rate discharged by the accumulator 6. In addition, the flow rate supplied to the high pressure inlet 9 is such that all of the pressure oil introduced into the valve inner chamber 19 through the valve high pressure chamber 16 and the valve flow path hole 20 is supplied to the upper cylinder chamber 15, thereby providing a piston (2). Let it descend.

In the conventional case, as shown in FIG. 2, the flow rate discharged from the cylinder base 12 and the accumulator 6 and the flow rate supplied to the high pressure inlet 9 are both the high pressure chamber 16 and the valve flow path 20. It enters into the valve inner chamber 19 through, and a pressure drop generate | occur | produces according to the opening area and passage flow volume formed by the valve flow path hole 20. As the pressure drop increases, the pressure in the cylinder chamber 12 increases when the piston descends, and the pressure in the cylinder chamber 15 decreases. As a result, the force for lowering the piston 2 decreases, thereby lowering the impact force of the breaker. In order to compensate for this problem, in order to enlarge the flow path area formed by the valve flow path hole 20, the diameter of the valve 4 should be increased or the valve stroke should be lengthened. In this case, the movement distance of the valve is increased and the volume of the valve is increased. The larger the weight and the greater the weight, the faster the valve changeover becomes difficult, which reduces the breaker's efficiency.

In the present invention, the pressure oil supplied to the cylinder upper chamber 15 when the piston descends is divided into two flow paths, the valve channel hole 20 and the accumulator-side high pressure chamber 16 ', so as to allow the valve to be of the same size and stroke. By making a large flow path, the pressure loss due to the large flow rate is greatly reduced. As a result, when the piston descends, the pressure difference between the cylinder upper and the lower can be reduced, and a high hitting speed can be obtained by applying a constant force to the piston during the piston lowering stroke.

The accumulator 6 functions to discharge the pressurized oil accumulated when the piston 2 rises when the piston descends, and the accumulation of the accumulator 6 is carried out at a low flow rate according to the rise of the piston 2. The pressure drop between and the chamber is small. Therefore, the volume of the accumulating oil accumulates in the balance between the pressure in the accumulator gas chamber 26 and the pressure in the cylinder base 12, and is sufficiently accumulated as the pressure increases, while the replenishment flow rate supplemented from the accumulator 6 is Since a large flow rate is required in a short time, if a large pressure difference is generated during the passage from the accumulator 6 to the cylinder chamber 15, the accumulator cannot supply all the pressure oil that the accumulator can replenish when the piston descends. Therefore, the amount of pressure oil accumulated at the next piston rise also becomes small. As a result, the pressure loss in the flow path results in insufficient performance of the accumulator.

FIG. 7 shows a state when the piston 2 continues to descend to reach the bottom dead center after FIG. When the piston 2 is lowered and the partial surface 28 of the piston is lowered to the position of the cylinder switching chamber 13, the cylinder switching chamber 13 is connected to the cylinder low pressure chamber 14, and the valve switching chamber 18 is switched to low pressure. , The valve 4 is started to descend by the downward force on the valve pressure receiving surface 23 by the high pressure that always acts on the valve pressure chamber 18 '. The piston 2 continues to descend and strikes the top of the chisel 8 at the bottom dead center. At this time, the valve 4 is pushed out of the valve switching chamber 18 as the valve descends and passes through the orifice 29. The back pressure is formed in the valve switching chamber 18, and this back pressure serves to adjust the descending speed of the valve 4. Here, the momentary valve 4 of the piston 2 is in the position of FIG. 7, and the flow rate supplied to the cylinder chamber 15 until the piston strikes continues to flow through the accumulator-side high pressure chamber 16 ′. The high pressure flow path connected to the valve inner chamber 19, the valve flow path hole 20, and the valve high pressure chamber 26, which were connected just before, is cut off immediately before the piston strikes by the lowering of the valve 4. At this time, since the valve flow path 20 is located on the inner wall of the valve housing between the valve high pressure chamber 16 and the valve low pressure chamber 17, the valve inner chamber 19 is connected only to the accumulator-side high pressure chamber 16 '.

When the piston (2) collides with the chisel (8) at the bottom dead center, an upward rebound movement is continued by the elasticity of the crushed object, the chisel and the piston immediately after the strike, and the piston (2) moves rapidly from the downward to the upward direction. Change. That is, the piston (2) is subjected to enormous acceleration at the moment of hitting, the fluid in the cylinder chamber 15 and the cylinder chamber 12 continues to flow in the direction that flows when the piston descends by inertia, so that the cylinder chamber 15 and the cylinder chamber At 12, a sudden change in pressure occurs. After the impact, the piston 2 rises for a short time due to the upward repulsion speed. At this time, a shock pressure caused by a sudden compression wave is generated in the cylinder chamber 15, and this shock pressure is in the form of a shock wave. As it propagates at high speed.

In the present invention, the impact pressure of the cylinder lost due to the piston strike is transmitted to the accumulator 6 by the valve mechanism as described above, thereby accumulating in the accumulator gas chamber 26, thereby functioning to alleviate the impact. . Therefore, the impact pressure is prevented from damaging or shortening the life of the hydraulic components or pipes that may occur when the shock pressure is transmitted to the high pressure inlet 9 or the low pressure outlet 10, thereby alleviating the vibration of the breaker.

In addition, immediately after the impact, the cylinder chamber 12 is rapidly dropped by the rebound rise of the piston 2, and may cause local cavitation on the wall surface of the cylinder chamber 12. In this case, since the accumulator 6 is always connected to the cylinder base 12, when the pressure drops due to the piston reaction rise, the flow rate is supplied from the oil chamber of the accumulator 6 to the cylinder base 12, thereby greatly reducing the pressure. To prevent them. Therefore, it is possible to reduce the repetitive load due to the load pressure fluctuation, etc. connected to the high pressure inlet (9), contributing to the extension of the pump life.

As described above, by installing the valve mechanism, the accumulator (6) and the flow path according to the present invention, by increasing the piston blow speed to improve the blow force of the breaker to increase the work efficiency of the breaker, impact pressure generated during the hit It is possible to provide a breaker that prevents damage to the breaker and main parts and shortens the life of the breaker and mitigates vibration during the breaker operation.

Claims (1)

A chisel 8 which is moved up and down to strike the crushed object; A piston (2) hydraulically driven up and down at the top of the chisel (8); A valve housing 3 having a high pressure inlet 9, a low pressure outlet 10, a valve high pressure chamber 16, a valve low pressure chamber 17, and a valve switching chamber 18; Valve 4; An accumulator 6 composed of an accumulator gas chamber 26 and a diaphragm 25; And a hydraulic breaker composed of a cylinder upper chamber (15), a cylinder low pressure chamber (14), a cylinder switching chamber (13), and a cylinder (1) having a cylinder chamber (12), wherein the high pressure inlet in the valve housing (3) is provided. A valve high pressure chamber 16 is installed in connection with (9), and the valve high pressure chamber 16 and the cylinder chamber 12 are formed to communicate with each other by forming a high pressure passage 11, and the valve high pressure chamber 16 is upper part. A valve hydraulic pressure chamber 18 ′ is installed in communication with the high pressure passage 11, a valve low pressure chamber 17 is installed in communication with the low pressure outlet 10 and in communication with the cylinder low pressure chamber 14, The accumulator-side high pressure chamber 16 'is installed at the bottom of the valve housing 3 so as to communicate with the accumulator 6 through the high pressure passage 11'. The valve switching chamber 18 is provided in communication with the cylinder switching chamber 18 through the flow path in which the orifice 29 is formed; A valve pressure receiving surface 23 is formed in the valve 4 so as to be positioned in the valve pressure receiving chamber 18 ', and a switching pressure receiving surface 24 is formed in the valve 4 so as to be located in the valve switching chamber 18. And a valve flow path hole 20 is formed in the valve 4 so that the valve high pressure chamber 16 and the valve low pressure chamber 17 communicate with the valve inner chamber 19 alternately. An opening surface is formed in the valve (4) between (16 ') and the valve inner chamber (19); In addition, a high pressure flow passage (11 ") is formed in communication with the compressor (6) is always in communication with the cylinder base 12, and connected through the accumulator-side high pressure chamber (16 ') and the high pressure passage (11'). Hydraulic breaker, characterized in that consisting of a pressure accumulator (6) is installed to be intermittently connected to the valve chamber 19 according to the position of the valve (4).