WO2012026571A1

WO2012026571A1 - Fluid pressure hammering device

Info

Publication number: WO2012026571A1
Application number: PCT/JP2011/069267
Authority: WO
Inventors: 矩男弘瀬
Original assignee: 株式会社テイサク
Priority date: 2010-08-27
Filing date: 2011-08-26
Publication date: 2012-03-01
Also published as: JP2013233595A

Abstract

In this fluid pressure hammering device, which automatically switches/controls the stroke of a piston in accordance with the rock quality of a rock to be pulverized, control accuracy is increased. A strike-switching pilot hole (40) for removing high-pressure oil during hammering is provided to a reversal chamber (5). By means of a fluid ejection valve (41) that operates by incurring the hydraulic pressure from the stroke-switching pilot hole (40), oil is successively collected in a fluid chamber (32) provided to a stroke switching valve (30), and when the amount of oil in the fluid chamber (32) exceeds a baseline amount, short strokes are switched to long strokes by means of the switching of the stroke switching valve (30).

Description

Fluid pressure hammer

The present invention relates to a hydraulic-type hammering device such as a hydraulic type, and in particular, a hydraulic-type hammering device capable of automatically increasing a hammering force when a crushed material such as a rock is hard and does not break even when hit for a certain time. It is about.

The work of crushing the rock mass etc. using a hydraulic hitting device presses the tip of the chisel of the hitting device against the crushed material and continuously hits the rear end of the chisel by the reciprocating motion of the piston inserted in the hitting device. Is done.
As for the striking force when the piston strikes the chisel, a larger striking force can be obtained by reciprocating the piston with a longer stroke when the thrust for urging the piston forward is equal.
There are various types of rocks, from soft rocks to hard rocks. When the rocks to be crushed are soft, the piston stroke is shortened. The crushing operation can be efficiently performed by increasing the stroke of the piston and operating in a mode in which the number of hits is small but the hitting force is strong.

Conventionally, as a method for automatically adjusting the stroke of the piston of the hydraulic hammering device according to the hardness of the rock mass, the amount of biting into the rock mass of the chisel is detected by the amount of advancement of the piston due to the hammering, and the piston stroke is switched. A method has been proposed. (Patent Document 1)
Furthermore, a method has been proposed in which the stroke is switched by utilizing the difference in pressure difference between the upper and lower chambers of the piston due to the difference in hardness of the crushed material. (Patent Document 2)

JP2003-311651 JP 2005-177899 A

In the striking device disclosed in Patent Document 1, the stroke is switched by detecting that the piston has advanced from a predetermined striking position. However, in a crushing operation using an actual striking device, the cylinder in which the piston is inserted is not spatially fixed, and is moved against the crushed material by a hydraulic excavator or the like. Moves forward from a predetermined striking position, but at the same time, the cylinder itself moves forward by the pressing force of a hydraulic excavator or the like, so the moving distance by which the piston moves forward from the predetermined striking position with respect to the cylinder becomes very delicate, and the chisel It was difficult to reliably detect the amount of biting into the crushed material, and it was difficult to perform accurate stroke control.

Further, in the method of switching the stroke based on the pressure difference between the upper and lower chambers of the piston disclosed in Patent Document 2, the pressure generated in each chamber at the time of striking is not only the hardness of the rock mass but also the oil temperature, viscosity, etc. Therefore, it is difficult to accurately detect the difference in generated pressure when striking hard rock and soft rock, and the change of stroke due to this difference is very unstable. It was.
Therefore, the present invention provides a fluid pressure striking device that eliminates such a problem.

In the fluid pressure striking device according to the first aspect of the present invention, a striking piston having a striking pressure receiving surface and a returning pressure receiving surface is fitted in a cylinder so as to be able to reciprocate, and a high pressure fluid pressure is always applied to the returning pressure receiving surface. The reversing chamber, which forms the pressure receiving surface for impact, causes the piston to reciprocate by alternately applying a high pressure fluid pressure and a low pressure fluid pressure via the main switching valve, and the stroke of the piston switches the stroke. The valve can be switched between a short stroke and a long stroke.
Further, on the inner wall of the piston sliding portion of the cylinder, a short pilot chamber that defines a short stroke of the piston and a long pilot chamber that defines a long stroke are formed in a groove shape,
The stroke switching valve has a fluid chamber that stores fluid according to the number of times or time that high-pressure fluid is supplied to the reversing chamber, and operates according to the amount of fluid in the fluid chamber. For a short time, when the return pressure receiving surface of the piston returns to the position corresponding to the short pilot chamber, the main switching valve is switched to supply high pressure fluid to the reversing chamber, and the fluid volume in the fluid chamber is larger than the reference volume. In this case, when the return pressure receiving surface of the piston returns to the position corresponding to the long pilot chamber, the main switching valve is switched to supply high pressure fluid to the reversing chamber.
According to the first invention of the present invention, the hydraulic pressure striking device operates at a short stroke when the amount of fluid stored in the fluid chamber is small at the beginning of the crushing operation, and is not crushed even if continuously struck for a certain period of time. When the amount of fluid stored in the fluid chamber sometimes exceeds the reference amount, it automatically switches to a longer stroke with stronger force. In this way, the hydraulic striking device is switched from a short stroke to a long stroke with the passage of time after the start of operation, so the piston stroke can be switched with high accuracy according to the hardness of the rock mass, efficiently. Crushing work can be performed.

The second invention of the present invention is the fluid pressure striking device according to the first invention, wherein when the fluid pressure in the reversing chamber is switched from a low pressure to a high pressure, the spool is operated to supply a predetermined amount of fluid to the fluid chamber. A fluid discharge valve is provided.
According to the second aspect of the present invention, every time the fluid pressure in the reversing chamber is switched from the low pressure to the high pressure, the fluid discharge valve supplies the pulsed fluid to the fluid chamber. Accordingly, the amount of fluid in the fluid chamber can be proportional to the number of piston operations, and when the number of piston operations reaches a predetermined number, the piston can be automatically switched from a short stroke to a long stroke.

A third invention of the present invention is the fluid pressure striking device of the second invention, characterized in that the operation stroke of the spool in the fluid discharge valve is adjustable.
According to the third aspect of the present invention, since the operation stroke of the spool in the fluid discharge valve can be adjusted, the amount of fluid per one time supplied from the fluid discharge valve to the fluid chamber can be adjusted. During operation, the speed at which the piston is switched from the short stroke to the long stroke can be adjusted by adjusting the increasing speed of the amount of fluid stored in the fluid chamber.

According to a fourth aspect of the present invention, there is provided the fluid pressure type striking device according to the first aspect, wherein an inflow throttle is provided for extracting the high pressure fluid in the reversing chamber by a predetermined amount per unit time and supplying the fluid chamber to the fluid chamber. It is characterized by.
According to the fourth aspect of the present invention, while high-pressure fluid is supplied to the reversing chamber, the fluid is stored in the fluid chamber at a constant speed via the inflow restrictor. Therefore, the amount of fluid in the fluid chamber can be proportional to the operation time of the hydraulic striking device, and when the operation time of the hydraulic striking device reaches a predetermined time, the piston is automatically changed from a short stroke to a long stroke. Can be switched to.

A fifth invention of the present invention is the fluid pressure type striking device according to any one of the first to fourth inventions, wherein a discharge restrictor for gradually discharging the stored fluid is connected to the fluid chamber. Features.
According to the fifth aspect of the present invention, the discharge restrictor is connected to the fluid chamber, and the fluid stored in the fluid chamber is gradually discharged. Therefore, the amount of fluid stored in the fluid chamber can be increased by adjusting the discharge amount. The speed can be adjusted.

A sixth aspect of the present invention is the fluid pressure striking device according to any one of the first to fifth aspects, wherein the stroke switching valve is communicated with the short pilot port communicated with the short pilot chamber and the long pilot chamber. When the fluid volume in the fluid chamber is less than the reference amount, the short pilot port and the long pilot port are connected, and when the fluid amount in the fluid chamber exceeds the reference amount, the short pilot port and the long pilot port are connected. The high-pressure fluid supplied to the return pressure receiving surface, which is cut off from the pilot port and supplied through the short pilot chamber or long pilot chamber, is removed from the long pilot port and supplied to the pilot port of the main switching valve. The high pressure fluid is supplied to the reversing chamber by switching the main switching valve. To.
According to the sixth aspect of the present invention, the stroke switching valve switches between the short stroke and the long stroke by simply connecting and shutting off the short pilot port and the long pilot port according to the amount of fluid in the fluid chamber. Therefore, the configuration of the stroke switching valve can be simplified.

A seventh aspect of the present invention is the fluid pressure striking device according to the first to sixth aspects of the present invention, wherein a discharge valve for discharging the stored fluid is connected to the fluid chamber when the reciprocation of the piston is stopped. It is characterized by being.
According to the seventh aspect of the present invention, since the discharge valve is connected to the fluid chamber, the fluid stored in the fluid chamber can be immediately discharged when the hydraulic striking device is stopped. For this reason, even when the hydraulic striking device is repeatedly operated and stopped in a short cycle, at the start of operation of the hydraulic striking device, the fluid can always be stored in the fluid chamber from the initial state. Regardless of the manner of operation, the accuracy of automatic switching from short stroke to long stroke can be improved.

1 is a schematic view of a first embodiment of a hydraulic striking device according to the present invention. It is explanatory drawing at the time of piston raising (at the time of an operation | movement start) in the said embodiment. It is explanatory drawing at the time of the piston fall start at the time of the short stroke in the said embodiment. It is explanatory drawing under the piston fall at the time of the short stroke in the said embodiment. It is explanatory drawing under the piston raising at the time of the short stroke in the said embodiment. It is explanatory drawing in the piston descending after switching to the long stroke in the said embodiment. It is explanatory drawing during the piston raising at the time of the long stroke in the said embodiment. It is explanatory drawing at the time of the piston fall start at the time of the long stroke in the said embodiment. The example which united the principal part in the said embodiment is shown. The example which replaced the unit in FIG. 9 with the simple unit is shown. It is the schematic of 2nd Embodiment of the hydraulic-type impact apparatus which concerns on this invention. It is the schematic of 3rd Embodiment of the hydraulic striking device which concerns on this invention.

<First Embodiment>
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows an outline of a hydraulic striking device according to an embodiment of the present invention, and FIGS. 2 to 8 sequentially show states of operation of the striking device of the present invention.
In the hydraulic striking device of the present invention, a piston 2 is inserted into a cylinder 1 so as to be capable of moving back and forth in the axial direction, a chisel 3 is mounted in front of the piston 2 (left side in the drawing), and a rear end portion of the piston 2 ( On the right side of the figure, there is provided a gas chamber 4 for energizing the piston 2 at the time of impact, for example, containing a gas such as nitrogen.

Further, in this striking device, a main switching valve 20 for switching the forward / backward movement of the piston 2, a stroke switching valve 30 for switching the stroke of the piston 2, and a fluid pressure signal for operating the stroke switching valve to switch the stroke are generated. And a pressure control valve 43 that regulates the fluid pressure of the fluid flowing into the pilot port 33 of the stroke switching valve 30.
The piston 2 includes a small diameter portion 2a, a first large diameter portion 2b, an intermediate portion 2c, a second large diameter portion 2d having the same diameter as the first large diameter portion, and an intermediate diameter portion 2e in order from the right shown in FIG. The diameter of the middle diameter part 2e is larger than the diameter of the small diameter part 2a and is smaller than the diameters of the

large diameter parts

2b and 2d. The right end surface of the first large diameter portion 2b is a ring-shaped impact pressure receiving surface 2u, and the left end surface of the second large diameter portion 2d is a ring-shaped return pressure receiving surface 2v.

A reversing chamber 5, a constantly low pressure chamber 11, a long pilot chamber 12, a short pilot chamber 13, and a constantly high pressure chamber 7 are formed in a ring-shaped groove on the inner wall of the piston sliding portion of the cylinder 1 from the right side of the figure. Yes. Also, the arrangement positions of the constant high pressure chamber 7, the short pilot chamber 13, the long pilot chamber 12, and the constant low pressure chamber 11 are arranged to switch the main switching valve 20 in accordance with the operating state of the piston 2 described later. is there. That is, the high pressure chamber 7 is always in communication with or disconnected from the short pilot chamber 13 or the long pilot chamber 12 depending on the position of the piston 2 during reciprocating motion, and the low pressure chamber 11 is always in communication with or out of communication with the long pilot chamber 12. It is arranged to become.

The hydraulic pump 10 serving as a hydraulic source is connected to a switching valve 53 that is switched by a pedal 51. When the pedal 51 is depressed, the high-pressure pipe 55 is connected to the discharge side of the hydraulic pump 10 by the switching valve 53. When the high pressure chamber 7 is always in a high pressure state and the pedal 51 is not depressed, the high pressure pipe 55 is connected to the low pressure pipe 52 and becomes a low pressure side (see FIG. 1).
Similarly, the oil tank 50 is always connected to the low-pressure chamber 11 via the low-pressure pipe 52 and can be switched between the state communicating with the reversing chamber 5 and the state shut off via the main switching valve 20. It is configured. That is, the main switching valve 20 is configured to be switched so that the reversing chamber 5 communicates with either the high pressure hydraulic pump 10 or the low pressure oil tank 50.

High pressure oil can be applied to one pilot port 20A of the main switching valve 20, and the other pilot port 20B is connected to the long pilot chamber 12. The main switching valve 20 is switched by operating.
That is, when high pressure oil acts on the pilot port 20B, the main selector valve 20 moves the spool of the main selector valve 20 to the right side in the figure so that the high pressure port 20b and the reverse port 20c communicate with each other. The high pressure oil applied to the pilot port 20A is pushed back to the left in the figure so that the low pressure port 20a and the reverse port 20c communicate with each other.

The stroke switching valve 30 is composed of an inserted spool 31 and a spring, and a fluid chamber 32 is provided inside the stroke switching valve 30 at a position opposed to the spring that applies a pressing force to the spool 31. While the oil amount in the fluid chamber 32 is less than the reference amount, the spool 31 is pushed rightward in the figure by the force of the spring, and the long pilot port 30b and the short pilot port 30c communicate with each other. On the other hand, when the amount of oil in the fluid chamber 32 gradually increases, the spool moves in the left direction against the spring force, and the amount of oil in the fluid chamber 32 exceeds the reference amount, the long pilot port 30b and the short circuit are shorted. The pilot port 30c is blocked. The stroke switching valve 30 is a spring type, but various types such as a hydraulic type and a gas type can be selected.

Further, in order to take out a pilot signal for stroke switching, a stroke switching pilot hole 40 is provided in the reversing chamber 5, and the stroke switching pilot hole 40 is connected to a fluid discharge valve 41. The fluid discharge valve 41 discharges a predetermined amount of oil when it receives a high pressure oil pressure from the stroke switching pilot hole 40, and the oil flows to the pressure control valve 43 to control the oil pressure. Since it flows into the fluid chamber 32 and is also connected to the oil tank 50 via the discharge variable throttle 45, the amount of oil accumulated in the fluid chamber 32 can be adjusted by the discharge variable throttle 45. That is, since the amount of oil accumulated in the fluid chamber 32 can be adjusted by adjusting the variable discharge throttle 45, the switching time from a short stroke to a long stroke, which will be described later, can be adjusted.
The fluid discharge valve 41 is provided with a check valve 42 that shuts off when the oil is discharged, and communicates and passes the oil when the oil is supplied to the fluid discharge valve 41.

Further, when the striking device is in operation, the oil stored in the fluid chamber 32 is retained, and when the operation is stopped, the oil is stored and the fluid chamber 32 is always in communication with the low-pressure chamber 11 so that the spool 31 is initialized. A pilot port operation check valve 44 for returning to the state is provided (corresponding to a discharge valve in the present invention).
The pilot port operation check valve 44 is disconnected from the fluid chamber 32 and the low-pressure chamber 11 at all times when high-pressure oil is acting, and communicates when low-pressure oil acts.
Therefore, in order to return the spool 31 to the initial state (short stroke), the fluid chamber 32 is always communicated with the low pressure chamber 11 via the pilot port operation check valve 44, and the fluid chamber 32 is Since it is possible to communicate with the oil tank 50 via the discharge variable throttle 45, the spool 31 can be returned to the initial state (short stroke) more reliably by the discharge variable throttle 45.

Next, referring to FIG. 2 to FIG. 8, when the hydraulic pressure striking device according to the present invention operates with a short stroke at the start of striking and the crushed material is hard and does not crush even if struck for a certain period of time, the striking force is automatically A striking operation that switches to an operation with a large long stroke will be described.
FIG. 2 is a view at the start of operation, and the chisel 3 is pressed against the crushed material by a hydraulic excavator or the like through the cylinder 1. Further, the piston 2 inserted in the cylinder 1 is located at the forward end (striking point) by its own weight.

Since the spool 31 inserted in the stroke switching valve 30 moves to the right side of the figure by the force of the spring, the short pilot chamber 13 and the long pilot chamber 12 communicate with each other via the short pilot port 30c and the long pilot port 30b. is doing.
The spool of the fluid discharge valve 41 connected to the stroke switching pilot hole 40 provided in the reversing chamber 5 is pushed upward in the figure by the force of the spring.
When the hydraulic pump 10 is driven and the pedal 51 is continuously depressed, the high pressure oil discharged from the hydraulic pump 10 flows into the pilot port 20A of the main switching valve 20 by the switching valve 53, while the pilot of the main switching valve 20 is driven. Since the port 20B is always in the low pressure chamber 11 through the long pilot chamber 12 and is in a low pressure, the spool of the main switching valve 20 moves to the left side in the figure, the low pressure port 20a and the reversing port 20c communicate, and the reversing chamber 5 Since it communicates with the oil tank 50, the pressure is low.

Further, the high pressure oil always flows into the high pressure chamber 7 via the high pressure pipe 55 and acts on the pilot port of the pilot operated check valve 44 to block the pilot operated check valve 44.
The high pressure oil that has always flowed into the high pressure chamber 7 acts on the return pressure receiving surface 2v and generates an upward force (right direction in the figure), while the pressure in the reversing chamber 5 acting on the impact pressure receiving surface 2u is low. The piston 2 starts to rise (right direction in the figure).

When the piston 2 rises and the return pressure receiving surface 2v reaches the position of the short pilot chamber 13, the high pressure oil in the high pressure chamber 7 always flows from the short pilot chamber 13 to the short pilot port 30c and the long pilot port 30b of the stroke switching valve 30. The long pilot chamber 12 flows into the pilot port 20B of the main switching valve 20 via the piping and the piping 23, and the spool of the main switching valve 20 moves to the right side in the figure by the action of this high pressure oil.
For this reason, the high pressure port 20b and the reversing port 20c of the main switching valve 20 communicate with each other, and the high pressure oil from the hydraulic pump 10 flows into the reversing chamber 5 through the reversing pipe 22, and the reversing chamber 5 becomes high pressure. (Figure 3)
For this reason, high pressure oil acts on both the pressure receiving surface 2u for impact and the pressure receiving surface 2v for return, but the pressure receiving area of the pressure receiving surface 2u for impact is formed larger than the pressure receiving area of the pressure receiving surface 2v for return. The force to move the piston 2 downward (leftward in the figure) becomes large, and the piston 2 is lowered (leftward in the figure) by being energized by the pressure of nitrogen gas or the like enclosed in the gas chamber 4 disposed behind the piston 2. And gradually accelerate and hit the chisel 3.

At the position where the piston 2 strikes the chisel 3 (at the point of hitting), the low pressure chamber 11 and the long pilot chamber 12 are always communicated via the communication chamber 6, and the long pilot chamber 12 is connected to the pilot port of the main switching valve 20 via the pipe 23. Since it communicates with 20B, the pilot port 20B has a low pressure, and the spool of the main switching valve 20 moves to the left in the figure.
For this reason, the low pressure port 20a and the reverse port 20c of the main switching valve 20 communicate with each other, and the reverse chamber 5 connected to the reverse port 20c via the reverse pipe 22 becomes low pressure, returning to the state of FIG.
As described above, by repeating the operations of FIGS. 2 to 5, the piston 2 continuously strikes the chisel 3 with a short stroke (the return pressure receiving surface 2v is turned back at the position of the short pilot chamber 13).

Next, the principle that the stroke of the piston 2 is automatically switched to the long stroke after the above-described continuous short stroke is repeated for a certain time will be described below.
During the stroke of the piston 2 (movement in the left direction in the figure), the high pressure oil that has flowed into the reversing chamber 5 flows into the fluid discharge valve 41 through the stroke switching pilot hole 40.
When this high-pressure oil acts on the spool of the fluid discharge valve 41, the spool moves downward in the figure and pushes out the oil accumulated in the inside at a high pressure. The high pressure oil pushed out from the fluid discharge valve 41 is always blocked by the check valve 42 in the direction of the low pressure chamber 11 and does not flow, and the amount discharged from the discharge variable throttle 45 is adjusted, and the pressure control valve It flows into the fluid chamber 32 from the pilot port 33 of the stroke switching valve 30 via 43.
At this time, high pressure is acting on the pilot port of the pilot operation check valve 44 inserted between the pilot port 33 of the stroke switching valve 30 and the low pressure chamber 11 at all times. The valve 44 is shut off. (Fig. 4)

After the piston 2 hits the chisel 3, when the return stroke (moving in the right direction in the figure) is reached, the reversing chamber 5 becomes low pressure, so the spool of the fluid discharge valve 41 connected to the reversing chamber 5 is While being pushed back, oil is always supplied from the low pressure chamber 11 through the check valve 42 into the fluid discharge valve 41.
During the return stroke of the piston, the pressure in the low pressure chamber 11 always increases slightly, but the pressure control valve 43 is adjusted so that the fluid pressure generated at this time does not act on the pilot port 33 of the stroke switching valve 30 (see FIG. 5).

As described above, the oil discharged from the fluid discharge valve 41 sequentially flows into the fluid chamber 32 of the stroke switching valve 30 in the stroke stroke of the piston 2, and the oil is always discharged from the low pressure chamber 11 in the return stroke. By repeating the operation of being supplied to 41, oil is accumulated in the fluid chamber 32, and the stroke switching valve moves in accordance with the accumulated amount to switch from the short stroke to the long stroke. That is, the oil accumulated in the fluid chamber 32 resists a spring pushing the spool 31 inserted in the stroke switching valve 30 in the right direction in the figure, and the spool 31 sequentially moves in the left direction in the figure, and the short pilot chamber 13 The short pilot port 30c connected to the long pilot port 30b and the long pilot port 30b connected to the long pilot chamber 12 (the pilot port 20B of the main switching valve 20) are blocked (FIG. 6).
The time until switching from the short stroke to the long stroke is adjusted by changing the discharge amount for each stroke by adjusting the operation stroke of the spool in the fluid discharge valve 41 or by adjusting the discharge variable throttle 45. Alternatively, the amount flowing into the fluid chamber 32 can be changed by adjusting both.

The piston 2 immediately after striking starts to rise (rightward in the drawing) because the reversing chamber 5 is at a low pressure and the pressure applied to the striking pressure receiving surface 2u is low. At this time, even if the return pressure receiving surface 2v reaches the position of the short pilot chamber 13 during the ascending process of the piston 2, the short pilot port 30c and the long pilot port 30b of the stroke switching valve 30 are in a disconnected state, and the long pilot chamber 12 Since the pressure of the pilot port 20B communicating with the (long pilot port 30b) via the pipe 23 does not change, the main switching valve 20 is not switched, and the return pressure receiving surface 2v of the piston 2 is positioned at the position of the short pilot chamber 13. And continue to rise (right direction in the figure) (FIG. 7).
When the return pressure receiving surface 2v reaches the position of the long pilot chamber 12, the high pressure oil always flowing into the high pressure chamber 7 flows from the long pilot chamber 12 to the pilot port 20B of the main switching valve 20 via the pipe 23. The pilot port 20B becomes high pressure, the spool of the main switching valve 20 is switched, and moves to the right side in the figure.
For this reason, the high pressure port 20b and the reversing port 20c of the main switching valve 20 communicate with each other, and the high pressure oil discharged from the hydraulic pump 10 flows into the reversing chamber 5 through the reversing pipe 22, and the reversing chamber 5 becomes high pressure (FIG. 8).

High pressure is applied to the pressure receiving surface 2u for impact, and the piston 2 starts to descend (in the left direction in the figure), and is further urged by nitrogen gas or the like enclosed in the gas chamber 4 to gradually accelerate and strike the chisel 3 To do.
At the position where the piston 2 strikes the chisel 3 (spot), the low pressure chamber 11 and the long pilot chamber 12 are always in communication with each other via the communication chamber 6, and the long pilot chamber 12 is connected to the pilot port 20 </ b> B of the main switching valve 20. Because of the communication, the pilot port 20B has a low pressure, and the spool of the main switching valve 20 moves to the left side in the figure. For this reason, the low pressure port 20a and the reverse port 20c of the switching valve communicate with each other, the reverse chamber 5 connected to the reverse port via the reverse pipe 22 becomes low pressure, and the piston 2 starts to rise again.

By repeating the above operation, the piston 2 causes the chisel 3 to move with a long stroke (the return pressure receiving surface 2v is folded back at the position of the long pilot chamber 12) while the spool 31 of the stroke switching valve 30 is located on the left side in the figure. Strike continuously.
When the long stroke is repeated and the crushed material breaks, when the pedal 51 is stopped, the high pressure pipe 55 is connected to the low pressure pipe 52 by the switching valve 53, and the high pressure oil is supplied to the striking device. Is stopped and the driving of the striking device is stopped. At this time, the supply of high-pressure oil to the pilot port of the pilot operation check valve 44 is also stopped, so that the pilot operation check valve 44 is opened, and the oil in the fluid chamber 32 of the stroke switching valve 30 is returned to the pilot operation reverse valve. It always flows out to the low-pressure chamber 11 through the stop valve 44, or escapes to the oil tank 50 through the discharge restrictor 45, or flows out to both.

For this reason, the spool 31 is moved to the right in the figure by the force of the spring, and the stroke switching valve 30 is reset to the initial state (the short pilot port 30c and the long pilot port 30b are in communication).
Therefore, when the striking device is actuated by stepping on the pedal 51 at the start of the next operation, the striking device starts from the short stroke striking in the state shown in FIGS. 2 to 8, and is automatically converted into a long stroke for striking.
The discharge variable throttle 45 allows time adjustment from a short stroke to a long stroke by adjusting the flow rate into the fluid chamber 32, and also enables switching from a long stroke to a short stroke.

As described above, when the crushed material is crushed within a certain time, the long stroke with a large number of strikes is performed. By switching to, more efficient crushing work can be performed.

Next, FIG. 9 and FIG. 10 show the unit 100 (FIG. 9) and the simple unit 100A (FIG. 10), and it is possible to easily use the hydraulic striking device according to the purpose of use.
That is, FIG. 9 is the same as FIG. 1 and shows a unit 100 that can automatically convert a short stroke to a long stroke, and FIG. 10 shows a simple unit 100A when used as a long stroke.
The unit 100 shown in FIG. 9 includes the stroke switching valve 30, the fluid discharge valve 41, the check valve 42, the pressure control valve 43, the pilot operation check valve 44, piping, and the like shown in FIG. When connected, the hydraulic striking device can automatically convert from a short stroke to a long stroke.

On the other hand, the simple unit 100A shown in FIG. 10 does not include the stroke switching valve 30, the fluid discharge valve 41, the check valve 42, the pressure control valve 43, and the pilot operation check valve 44, and the stroke switching pilot. The piping connected to the hole 40, the constant high pressure chamber 7, the constant low pressure chamber 11, the short pilot chamber 13, etc. is closed.

The hydrostatic striking device when the unit 100 is installed can automatically convert from a short stroke to a long stroke as already described above.
On the other hand, when the simple unit 100A is installed, the high-pressure pipe 55 is connected to the discharge side of the hydraulic pump 10 via the pedal 51, and the high-pressure chamber 7 is always in a high-pressure state. Further, the reversing chamber 5 becomes high pressure via the main switching valve 20, and high pressure oil acts on both the impact pressure receiving surface 2u and the return pressure receiving surface 2v. However, the pressure receiving area of the impact pressure receiving surface 2u is as follows. Since it is formed larger than the pressure receiving area of the return pressure receiving surface 2v, the force for moving the piston 2 downward (to the left in the figure) becomes large, and further nitrogen gas sealed in the gas chamber 4 disposed behind the piston 2 or the like. The piston 2 starts to descend (in the left direction in the figure) and is gradually accelerated to strike the chisel 3.

Further, at the position where the piston 2 strikes the chisel 3 (at the point of hitting), the low pressure chamber 11 and the long pilot chamber 12 are always communicated via the communication chamber 6, and the long pilot chamber 12 is connected to the main switching valve 20 via the pipe 23. Since the pilot port 20B communicates with the pilot port 20B, the pilot port 20B has a low pressure, and the spool of the main switching valve 20 moves to the left side in the figure. For this reason, the low pressure port 20a of the main switching valve 20 and the reverse port 20c communicate with each other, the reverse chamber 5 connected to the reverse port 20c via the reverse pipe 22 becomes low pressure, and the piston 2 starts to rise again. .
The piston 2 repeats the long stroke operation in which the return pressure receiving surface 2v rises until it reaches the long pilot chamber 12, and then starts to descend.
As described above, when the unit 100 is set in the fluid pressure striking device, the striking device can be automatically converted from a short stroke to a long stroke. When the simple unit 100A is provided, the striking device has a long stroke. Can easily cope with the situation.

<Second Embodiment>
FIG. 11 shows a second embodiment of the present invention. The second embodiment is characterized in that an inflow variable throttle 46 and a check valve 47 are provided in series instead of the fluid discharge valve 41 in the first embodiment. Other configurations in the second embodiment are the same as those in the first embodiment described above, and the same portions are denoted by the same reference numerals and the description thereof is omitted.
In the fluid discharge valve 41 of the first embodiment, a certain amount of oil is supplied to the fluid chamber 32 when the fluid pressure in the reversing chamber 5 changes from low pressure to high pressure. On the other hand, in the variable throttle 46 for inflow of 2nd Embodiment, the high pressure oil of the inversion chamber 5 is extracted by predetermined amount per unit time, and is supplied to the fluid chamber 32. FIG. The check valve 47 prevents oil from flowing back into the reversing chamber 5 via the check valve 42.
As a result, the oil is stored in the fluid chamber 32 at a constant speed via the inflow variable throttle 46 while the high-pressure oil is supplied to the reversing chamber 5. Accordingly, the amount of oil in the fluid chamber 32 can be increased in proportion to the operation time of the fluid pressure striking device. When the operation time of the fluid pressure striking device reaches a predetermined time, the piston is moved from the short stroke to the long stroke. Can automatically switch to stroke.

<Third Embodiment>
FIG. 12 shows a third embodiment of the present invention. The third embodiment is characterized in that the pilot operated check valve 44 in the first embodiment is deleted. Other configurations in the third embodiment are the same as those in the first embodiment described above, and the same portions are denoted by the same reference numerals and the description thereof is omitted.
In the first embodiment, the pilot operation check valve 44 functions to discharge the oil stored in the fluid chamber 32 when the operation of the striking device is stopped. In the third embodiment, the pilot operation check valve 44 performs this pilot operation. Since there is no check valve 44, the oil stored in the fluid chamber 32 is discharged through the discharge restrictor 45 when the operation of the striking device is stopped. The oil discharge by the discharge variable throttle 45 requires a longer time than the case of using the pilot operated check valve 44, but the amount of oil remaining in the fluid chamber 32 when the operation of the striking device is resumed is equivalent to the initial state. So that the discharge time is adjusted.
As a result, in the third embodiment, even if the pilot operation check valve 44 in the first embodiment is deleted, the same function as the striking device can be achieved.

The present invention is not limited to the appearance and configuration described in the above embodiment, and various modifications, additions, and deletions are possible without departing from the spirit of the present invention. For example, the discharge variable throttle 45 in each embodiment and the inflow variable throttle 46 in the second embodiment may be a simple throttle without a variable function.

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Piston 2a Small diameter part 2b 1st large diameter part 2c Intermediate | middle part 2d 2nd large diameter part 2e Medium diameter part 2u Impact pressure receiving surface 2v Return pressure receiving surface 3 Chisel 4 Gas chamber 5 Reversing chamber 6 Communication chamber 7 Always high pressure Chamber 10 Hydraulic pump 11 Normal low pressure chamber 12 Long pilot chamber 13 Short pilot chamber 20 Main switching valve 20A Pilot port (always high pressure)
20B Pilot port (reverse)
20a Low pressure port 20b High pressure port 20c Reverse port 22 Reverse pipe 30 Stroke switching valve 30a Low pressure port 30b Long pilot port 30c Short pilot port 31 Spool 32 Fluid chamber 33 Pilot port 40 Pilot hole 41 for stroke switching Fluid discharge valve 42 Check valve 43 Pressure control valve 44 Pilot operated check valve (discharge valve)
45 Variable aperture for discharge (throttle for discharge)
46 Variable throttle for inflow (throttle for inflow)
47 Check valve

Claims

A striking piston having a striking pressure receiving surface and a return pressure receiving surface is fitted in the cylinder so as to be able to reciprocate, and a high pressure fluid pressure is always applied to the return pressure receiving surface to form a reversing chamber that forms the striking pressure receiving surface. Is configured to reciprocate the piston by alternately applying high and low fluid pressures via the main switching valve, and the stroke of the piston can be switched between short stroke and long stroke by the stroke switching valve. A hydraulic striking device, comprising:
On the inner wall of the piston sliding portion of the cylinder, a short pilot chamber that defines a short stroke of the piston and a long pilot chamber that defines a long stroke are each formed in a groove shape,
The stroke switching valve includes a fluid chamber that stores fluid according to the number of times or time when a high-pressure fluid is supplied to the reversing chamber, and operates according to the amount of fluid in the fluid chamber. When the return pressure receiving surface of the piston returns to the position corresponding to the short pilot chamber, the main switching valve is switched to supply high-pressure fluid to the reversing chamber. When the number is increased, the fluid pressure type striking device is characterized in that when the return pressure receiving surface of the piston returns to the position corresponding to the long pilot chamber, the high pressure fluid is supplied to the reversing chamber by switching the main switching valve.
The hydraulic striking device according to claim 1,
A fluid pressure striking device, wherein a fluid discharge valve is provided to supply a predetermined amount of fluid to the fluid chamber by operating the spool when the fluid pressure in the reversing chamber is switched from low pressure to high pressure.
The hydraulic striking device according to claim 2,
A hydraulic striking device characterized in that an operating stroke of a spool in the fluid discharge valve can be adjusted.
The hydraulic striking device according to claim 1,
A fluid pressure type striking device, characterized in that an inflow restrictor is provided for extracting a predetermined amount of high-pressure fluid in a reversing chamber per unit time and supplying it to the fluid chamber.
A hydraulic pressure striking device according to any one of claims 1 to 4,
The fluid pressure striking device is characterized in that a discharge throttle for gradually discharging the stored fluid is connected to the fluid chamber.
A hydraulic striking device according to any one of claims 1 to 5,
The stroke switching valve includes a short pilot port communicated with the short pilot chamber, and a long pilot port communicated with the long pilot chamber,
When the fluid volume in the fluid chamber is less than the reference amount, the short pilot port and the long pilot port are communicated. When the fluid amount in the fluid chamber is greater than the reference amount, the short pilot port and the long pilot port are communicated. The high-pressure fluid supplied to the return pressure receiving surface that is shut off and supplied through the short pilot chamber or the long pilot chamber is taken out from the long pilot port and supplied to the pilot port of the main switching valve. A fluid pressure striking device characterized in that a high pressure fluid is supplied to the reversing chamber by switching operation.
A fluid pressure striking device according to any one of claims 1 to 6,
The fluid pressure striking device is characterized in that the fluid chamber is connected with a discharge valve for discharging the stored fluid when the reciprocation of the piston is stopped.