JPH02298475A - Stroke tool - Google Patents

Abstract

PURPOSE:To select the stroke of a piston according to the hardness of the body to be struck by driving a change-over operating time selecting means by the driving pressure corresponding to the impact pressure generated in the piston rear chamber by the reaction of the stroke time, selecting the change-over operation time of a switching means, and reversing the moving direction of the piston. CONSTITUTION:In the case of the body to be struck being a medium hard rock, more oils are flowed into the communicating pass of a selection piston 20 side via a switch valve 24 from a piston rear chamber 12 accordingly because of the impact pressure generated in the piston rear chamber 12 becoming larger than the case of a soft rock, when a hammer 4 strikes a chisel 34. When this high pressure oil intrudes into the pressure chamber 28 of a flow adjusting valve 25, a spool 30 is pushed further, a port 31 is opened and the high pressure oil in the pressure chamber 28 is discharged via this port 31 and the small hole 30a of the spool 30. Consequently, the pressure of the communication pass between the selection piston 20 and flow adjusting valve 25 is kept in a high state compared to the case of a soft rock and the stroke distances of pistons 2, 3 become l2.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a striking tool such as a plying plate, and more particularly to a striking tool that obtains striking force by using the pressure of a pressurized fluid. .

[Prior Art] Conventionally, since impact tools such as plate-cutting plates require a large impact force, the impact force has been obtained using the pressure of a pressure fluid such as high-pressure oil. As a type of striking tool, a configuration is known in which a piston rear chamber of a cylinder is pressurized and a piston front chamber is depressurized to advance the piston and obtain a striking force.

For example, in the configuration disclosed in Japanese Patent Publication No. 51-48132, a switching valve switches the flow of pressurized fluid so as to pressurize one of the front chamber and the rear chamber of the piston and reduce the pressure of the other. is provided. The cylinder is provided with a plurality of ports along its axial direction, and through these ports, pressure fluid is supplied from the piston front chamber to the spool of the switching valve, and this pressure fluid is discharged to the outside. The flow path of the switching valve can be switched depending on the operation. Also, the above board 1
The communication path formed between ~ and the switching valve is opened and closed by a movable pin that intersects with these communication paths.

According to such a configuration, by moving the pin, a boat communicating with the switching valve is selected, and the timing of switching the flow path of the switching valve is controlled according to the position of the boat. Accordingly, the position where the piston retreats after impact can be selected, and the stroke of the piston can be changed to obtain impact force that is appropriate for the rock type.

[Problem to be solved by the invention]

However, with the conventional configuration described above, although the stroke of the piston can be changed, if the pin cannot be moved by remote control, the pin can be adjusted by tightening or loosening the bolt provided on the tool body. Therefore, each time the rock quality of the object to be hit changes, the work must be interrupted and the above operations performed, reducing work efficiency. In addition, if the pin can be moved by remote control, the hassle of tightening and loosening bolts can be eliminated, but the pin must be moved every time the rock quality of the object being hit changes. As a matter of fact, a decline in work efficiency cannot be avoided.

[Means for Solving the Problems] In order to solve the problems mentioned above, the impact tool according to the present invention includes a piston that moves reciprocally within a cylinder, and a cylinder that moves in a direction that reverses the direction of movement of the piston. Bis I・
a switching means for switching between a flow path for supplying pressure fluid and a flow path for discharging pressure fluid to at least one of the front chamber and the rear chamber of the piston; and a switching operation IL'n! of the switching means driven by pressure. It is equipped with a switching operation jυ1 selection means for selecting IJI, and a driving pressure generation means for generating a substantially constant pressure according to the impact pressure generated in the piston rear chamber so as to drive the switching operation L% period selection means. It is characterized by

(Function) According to the above configuration, when impact pressure is generated in the rear chamber of the screw due to the reaction of the impact, the driving pressure generating means generates a substantially constant pressure corresponding to the impact pressure, and this pressure The cutting operation timing selection means driven by selects the switching operation timing of the switching means. Since the switching means performs the switching operation in accordance with the switching operation timing, the direction of movement of the piston can be reversed at a position corresponding to the impact pressure in the piston rear chamber.

- Impact pressure varies depending on the hardness of the object being hit, so
With the above configuration, the stroke of the piston can be automatically selected accordingly.

Therefore, when changing the stroke of the piston according to the hardness of the object to be struck, there is no need to manually select the switching operation timing of the switching means, and the work is repeated every time the hardness of the object to be struck changes. This eliminates the hassle of interruptions and greatly improves work efficiency.

(Example 1) An example of the present invention will be described below based on FIGS. 1 to 4.

As shown in FIG. 1(a), pistons 2 and 3 are provided within the cylinder 1 so as to be able to freely reciprocate. Piston 2
・3B, the striking force is generated by the reciprocating movement of the pistons 2 and 3.
They are coaxially connected at a predetermined interval by a hammer 4 of one unit. The hammer 4 has a pressure receiving area larger than the pressure receiving surface of the piston 3 or the pressure receiving surface of the piston 2,
The rear part of the screws 1 to 2 has a smaller diameter than the front parts of the screws 1 to 2. In addition, boats 5 and 6 are installed on the inner peripheral surface of the cylinder 1, the front end and the rear end, respectively, and screws 1 to 6 are installed at appropriate intervals between the balls 1 to 5 and 6, respectively. 2.3 Step l-1: Step 1 for selecting J-ri. r-1-ri Itshaku boat 7-9
, and an oil drain boat 10 for discharging high-pressure oil. The stroke selection boats 7 to 9 each move a distance ρ1 ·! backward from the front end surface of the piston 2 that is stopped at the striking position. 2 ・T, is provided at the position.

Further, within the cylinder 1, a piston front chamber 11 is formed in front of the screw 1-2, and a piston rear chamber 12 is formed behind the screw 1-2. High-pressure oil is always supplied to the piston front chamber 11 via the boat 5, while high-pressure oil is supplied to the piston rear chamber 12 via the switching valve 13 and is discharged.

The switching valve 13 serving as a switching means has a cylindrical spool 14 that moves reciprocally inside the main body, and boats 15 to 18 are provided at appropriate intervals on the inner peripheral surface of the main body. The spool 14 has pressure receiving surfaces 14a and 1 at both ends.
4b, and the pressure receiving surface 1.4b is provided so as to have a larger pressure receiving area than the pressure receiving surface 14a. The spool 14 is provided with a pressure receiving surface 1.4c on its outer circumferential surface to which high pressure oil is supplied from the boat 17, and a groove 14d that communicates between the boats 15 and 16 when performing full oiling of the piston rear chamber 12. It is provided. Pressure receiving surface 14c
The pressure receiving area is set such that the total pressure receiving area with the pressure receiving surface 14a is larger than the pressure receiving area of the pressure receiving surface 14b.

The switching valve 13 is configured such that high-pressure oil is supplied from the pressure-receiving surface 14a side to the pressure-receiving surface 14b side through the hollow part, while the high-pressure oil is discharged via the boat 16 to the piston rear chamber 12. The high-pressure oil supply and high-pressure oil discharge from the screw I/N rear chamber 12 are carried out via the boat 15. Further, the boat 18 is always maintained at a low pressure so that the spool 14 can be easily moved. Note that the flow rate of high-pressure oil discharged from the boat 16 is restricted by an orifice 19.

Cylinder 1 stroke selection boat~7~9 and switching valve 1
A selection pin 20 serving as a switching operation timing selection means is provided in the communication path between the boat 17 and the boat 17 so as to intersect with the communication path. One end of the selection pin 20 is urged by a spring 21, while a pressure receiving surface 20a is provided at the other end, and the pressure received by the pressure receiving surface 20a is as follows.
It is designed to move when it becomes larger than the force. Further, the selection pin 20 is provided with a groove 201 on its outer circumferential surface, and by moving as described above, the selection pin 20 can be moved between the stroke selection boat 7 and the boat 17, or between the stroke selection port 8 and the boat. It is designed to communicate with 17. Further, the stroke selection boat 9 and the boat 17 are always in communication via a communication groove 22 provided around the selection pin 20.

On the other hand, the driving pressure generating means 23 is composed of an on-off valve 24 and a flow rate regulating valve 25. The on-off valve 24 is closed by a spool 27 that is biased by a spring 26.
When the pressure in the piston rear chamber 12 exceeds a predetermined reference pressure, the spool 27 moves to form a flow path, allowing the high pressure oil in the piston rear chamber 12 to flow toward the selection pin 20 side. The spool 27 is provided with a small hole 27a, and by discharging high-pressure oil through this small hole 27a, the spool 27 is quickly moved when the pressure in the piston rear chamber 12 becomes lower than the standard pressure. It is designed to block the flow path.

The flow rate adjustment valve 25 is provided between the on-off valve 24 and the selection pin 2°, and when the pressure in the communication path between them increases, the pressure chamber 2
When the high-pressure oil enters 8, the spool 3o, which is urged by the springs 29, moves. The flow rate adjustment valve 25 discharges the high pressure oil flowing into the pressure chamber 2B through a small hole 30a provided in the spool 30.
The high pressure oil in the pressure chamber 28 is discharged via boats 31 and 32 provided at different positions.

Further, the flow rate of high-pressure oil discharged from the bows 1 to 31 is restricted by an orifice 33.

The operation in the configuration described above will be explained in the case where the object to be hit is a soft rock.

When the hammer 4 hits the chisel 34, an impact pressure is generated in the piston rear chamber 12 due to the reaction. When this impact pressure becomes equal to or higher than a predetermined reference pressure, the on-off valve 24 opens and the high pressure oil in the piston rear chamber 12 flows into the communication passage on the selection bin 20 side. When this high-pressure oil enters the pressure chamber 2B of the flow rate adjustment valve 25, the spool 30 is pushed and tries to move.
Since the high-pressure oil is discharged, the pressure in the pressure chamber 28 is kept almost constant.

The impact pressure generated in the piston rear chamber 12 only slightly exceeds the above reference pressure because the reaction caused by the impact is small, so the amount of oil flowing from the on-off valve 24 to the communication path on the selection pin 20 side is relatively small, and the flow rate is low. Most of it is discharged via the regulating valve 25. Therefore, the pressure in the communication path hardly increases, and the selection pin 20 does not move. Therefore, as shown in FIG. 1(a), the stroke selection boat 7 of the cylinder 1 communicates with the port 17 of the switching valve 13 via the groove 20h of the selection pin 20.

At this time, the high pressure oil supplied to the pressure receiving surface 14c of the spool 14 is discharged from the port 17 via the communication groove 22 and the oil drain bows 1 to 10 of the cylinder 1. Then, the force acting on the pressure receiving surface 14b of the spool 14 is
When the force becomes larger than the force acting on a, it moves to the position shown in the figure. In this position, ports 15 and 16 are in communication, and high pressure oil in the piston rear chamber 12 is in communication with ports 15 and 16.
16.

By the way, the pressure in the piston rear chamber 12 decreases due to the discharge of high pressure oil, while the piston front chamber 11 is always supplied with high pressure oil, so a difference in pressure between the piston rear chamber 12 and the piston rear chamber 12 occurs. 3 retreats from the striking position at high speed,
There is a risk that the timing at which the front chamber 11 and the selection boards 1 to 7 are communicated with each other may be delayed. However,
Since the flow rate of high-pressure oil discharged from the piston rear chamber 12 is restricted by the orifice 19, the pressure in the piston rear chamber 12 does not drop rapidly, and the speed at which the screws 1 and 3 retreat is reduced. It will be done.

As shown in FIG. 1(b), when the pistons 2 and 3 and the hammer 4 move back a distance of 1 litl E + from the striking position, the stroke selection ports 1-9 are closed by the screws I and 2, while the stroke selection ports 7 is the piston front chamber 1
1, to the port 17 of the switching valve 13,
High pressure oil is supplied through the stroke selection boat 7 and the groove 20b of the selection pin 20. The spool 14 is
Pressure receiving surface], 4a and pressure receiving surface 14c and pressure receiving surface 1.4
b Move to the position shown in the figure depending on the pressure receiving area. Then, high pressure oil flows through the port 15 into the piston rear chamber 1.
2, and the pressure in the piston rear chamber 12 increases. The same high-pressure oil is supplied to the piston front chamber 11 and the screw I/N rear chamber 12, but due to the difference in pressure receiving area between piston 3 and piston 2, pistons 2 and 3 are far apart! .

While moving forward with a stroke of , the hammer 4 strikes the chisel 34.

Here, changes in the pressure in the piston rear chamber 12 will be explained.

As shown in 2nd [1J (a), the pressure in the piston rear chamber 12 increases rapidly when high pressure oil is supplied at point a, and as the pistons 2 and 3 move forward, it decreases slightly due to loss etc. When the piston 2 passes the stroke selection boat 9, high-pressure oil is discharged from the port 17 of the switching valve 13, so the high-pressure oil in the piston rear chamber 12 is discharged by the switching operation of the switching valve 13, and the high-pressure oil is rapidly moved at five points. descend. Then, the pressure in the piston rear chamber 12 becomes an impact pressure at point C where the impact is made and fluctuates greatly, and the peak pressure of the fluctuation is the reference pressure (
For example, the height exceeds 230 kg/c+fl).

Furthermore, as shown in FIG. 2(b) when the above pressure change is expanded in the time axis direction, the time 1=j during which the peak of the pressure fluctuation after impact continuously rotates around the reference value by -1, Approximately 4
0+ns, and each time the on-off valve 24 opens during this time.

Since the peak pressure of the above-mentioned fluctuation varies depending on the hardness of the object to be hit, that is, the rock quality, the present invention utilizes this peak pressure to drive the selection pin 2'0 as described in "-". It is configured as follows.

Next, the operation when the object to be hit is a medium-hard layer will be explained based on FIG. 3.

When the hammer 4 hits the chisel 34, the impact pressure generated in the piston rear chamber 12 is greater than in the case of soft rock, so the selection pin 20 is moved from the piston rear chamber 12 via the on-off valve 24 accordingly. The amount of oil flowing into the communication passage increases. When this high-pressure oil enters the pressure chamber 28 of the flow rate adjustment valve 25, the spool 30 is further pushed to open the port 31, and the high-pressure oil in the pressure chamber 28 is discharged through this port 31 and the small hole 30a of the spool 30. be done. This results in
The pressure in the communication path between the selection pin 20 and the flow M regulating valve 25 is kept relatively high in the case of the soft rock, and this pressure acts as a driving pressure, so that the selection pin 20
moves against the biasing force of the spring 21, and the stroke selection boat 8 communicates with the boat 17 via the groove 20b.

Pistons 2 and 3 and hammer 4 are at a distance of 1 l from the striking position.
iI[x 2 When the piston moves backward, the stroke selection bow 1-8 communicates with the piston front chamber 11, so that high pressure oil is supplied to the boat 17 of the switching valve 13, and the spool 14 moves to the position shown. Screws 1 to rear chamber 12 are bow I/15
When supplied with high pressure oil via the pistons 2 and 3 move forward with a stroke of 2, the hammer 4 strikes the chisel 34.

Furthermore, the operation when the object to be hit is a hard rock will be explained based on FIG. 4.

In this case, the impact pressure generated in the piston rear chamber 12 becomes higher than before the medium-hard piston, and the amount of oil flowing into the selection pin 20 side via the on-off valve 24 also increases accordingly. When the high pressure oil that has flowed in through the on-off valve 24 enters the pressure chamber 28 of the flow rate adjustment valve 25, the spool 30 is further pushed by the pressure increase in the pressure chamber 28, and the boats 31 and 32 are opened.

The high pressure oil in the pressure chamber 28 is brought out through the boats 31 and 32 and the small hole 30a of the spool 30, and the pressure in the communication path between the selection pin 20 and the flow rate adjustment valve 25 is This pressure acts as a driving pressure and the selection pin 2 is kept in a higher state than in the case of
0 moves, and the stroke selection boat 9 communicates with the boat 17 via the groove 20b.

Pistons 2 and 3 and hammer 4 are at a distance l from the striking position
:l When moving backward, the stroke selection boat 9 communicates with the piston front chamber 11, so that the boat 1 of the switching valve 13
High pressure oil is supplied to 7, and the spool 14 moves to the position shown. When high pressure oil is supplied to the piston rear chamber 12 via the boat 15, the pistons 2 and 3 move forward with a stroke of a distance 13, and the hammer 4 strikes the chisel 34.

[Embodiment 2] Next, another embodiment of the present invention will be described based on FIGS. 5 and 6. It should be noted that members having the same functions as those in the first embodiment are given the same numbers and their explanations will be omitted.

In this embodiment, as shown in FIG.
Similar to the first embodiment shown in the figure, the pistons 2 and 3 and the hammer 4 provided in the cylinder 1, and the switching valve 13
and a selection pin 20.

The drive pressure driver 1 means 23' is a CPU that performs arithmetic processing, etc.
35, an A/D converter 36, a RAM 37, and a ROM 3.
8 and an output device 39 are connected. A pressure detection means 40 such as a pressure sensor is connected to the A/D converter 36, while a servo control means 40 is connected to the output device 39.
1 is connected.

The CPU 35 reads the peak pressure that exceeds a predetermined reference pressure from the pressure data detected by the pressure detection means 40, and calculates the average value of the peak pressures described in 1. In addition, the CPU 35
Compare the peak pressure of each compressive strength of the piston rear chamber 12 stored in M38 with the above calculation result, and determine the appropriateness of the pistons 2 and 3 from the stroke of each compressive strength stored in ROM 38 depending on the dirt. Now you can select the stroke. Further, the servo control 11 means 41 is a CPU
The pressure of the pressure reducing valve 42 is adjusted by the output signal converted by the ζ output device 39 according to the output data of the pressure reducing valve 42. The pressure reducing valve 42 reduces the pressure of high-pressure oil pressurized by the hydraulic pump 43 in accordance with the spring pressure, and supplies the reduced pressure to the selection pin 20.

The procedure for switching the selection pin 20 in the above configuration is not shown in FIG. - Explain based on the chart.

First, the pressure in the piston rear chamber 12 is detected by the first stage of pressure detection 40 (SL), and the CPU 35 reads the peak pressure higher than the reference pressure from the pressure data encoded by the A/D converter 36 (S2). . In addition, the CPU 35
The average value of the pressure peak values noted in - is calculated (S3:), and this calculation result is compared with the peak pressure for each compressive strength stored in R0M38 (S4). Then, the stroke corresponding to the comparison result is called from the ROM 38 and set. For example, here, the reference peak pressure p mi, ·P, 38 is set, and the average peak pressure is set. If the peak pressure is smaller than P0.7, the stroke I is set (S5). In addition, the average peak pressure is greater than or equal to the peak pressure JP, ia and the peak pressure P, 8,
If it is below, stroke 12 is set (S6)
. Furthermore, the average peak pressure is peak pressure P 118X
If larger, stroke 13 is set (S7)
.

Subsequently, the output device 39 sends out an output signal according to the flow set by the CPU 35, and the servo control means 41 operates the pressure reducing valve 42, thereby controlling the pressure (S8). The selection pin 20 is driven by the above pressure and moves to select the stroke set in steps 85 to S7.

In the first embodiment and this embodiment, the piston front chamber 11 is always maintained at a high pressure, while the piston rear chamber 12 is pressurized or depressurized by the switching valve 13, but the present invention is not limited to this. When pressurizing either the piston 1111 chamber 11 or the piston rear chamber 12 as in the conventional example,
A valve that reduces the pressure on the other side may be used.

〔Effect of the invention〕

The impact tool according to the present invention is a screw that can be moved reciprocally within a cylinder as described below.・Switching for switching between a flow path that supplies pressure fluid to at least one of the piston front chamber or the piston rear chamber of the cylinder and a flow path that outputs pressure fluid H1 so as to reverse the movement direction of the screws I and N. means, and when the switching means is driven by pressure, the switching operation is 1! The structure includes a switching operation timing selection means for selecting J1, and a driving pressure generation means for generating a substantially constant pressure according to the impact pressure generated in the piston rear chamber so as to drive the switching operation timing selection means. .

According to this, the switching operation timing selection means is driven by the driving pressure corresponding to the impact pressure generated in the rear chamber of the piston due to the reaction at the time of impact, and the switching operation timing of the switching means is selected, and at this operation timing, the piston The direction of motion of is reversed. Therefore, the stroke of the piston can be selected based on the impact pressure, which varies depending on the hardness of the object to be hit.

Therefore, when changing the stroke of the piston according to the hardness of the object to be struck, there is no need to manually select the switching operation timing of the switching means, and the work is repeated every time the hardness of the object to be struck changes. This eliminates the inconvenience of interruptions, and has the effect of significantly improving work efficiency.

[Brief explanation of drawings]

1 to 4 show one embodiment of the present invention. FIGS. 1(a) and 1(b) are circuit diagrams showing the operation of the impact tool when impacting soft rock. FIG. 2(a) is a graph showing pressure changes in the rear chamber of the piston. Figure 2 (b) shows the pressure change in the rear chamber of the piston (
2 is a graph that expands a) in the time axis direction. FIG. 3 is a circuit diagram showing the operation of the impact tool when impacting medium-hard rock. FIG. 4 is a circuit diagram showing the operation of the impact tool when impacting hard rock. 5 and 6 show other embodiments of the invention. FIG. 5 is a circuit diagram showing the structure of the impact tool. FIG. 6 is a flowchart showing the procedure for generating drive pressure for the control pin. 1 is a cylinder, 2 and 3 are pistons, 12 is a rear chamber of the piston, 13 is a switching valve (switching means), 20 is a selection pin (switching operation timing selection means), and 23 and 23' are drive pressure generating means.

Claims (1)

[Claims] 1. A piston that reciprocates within the cylinder, a flow path that supplies pressure fluid to at least one of the piston front chamber or the piston rear chamber of the cylinder, and a flow path that discharges the pressure fluid so as to reverse the direction of movement of the piston. a switching means for switching the switching operation timing of the switching means; a switching operation timing selection means for selecting the switching operation timing of the switching means driven by pressure; A striking tool comprising: drive pressure generating means that generates a substantially constant pressure.