JPH02298476A - Stroke tool - Google Patents

Abstract

PURPOSE:To obviate the necessity to equip a lot of branching passages for changing the stroke length of a piston by forming a flow groove communicating with a switching valve in order to change over the switching valve in a acting state capable of advancing a piston at the time when the piston is retreated in a specific distance on the face of the sliding side with the piston in a sleeve. CONSTITUTION:When a sleeve 6 is moved in the axial direction of a piston 7 and the position is changed, a flow groove 6a formed on this sleeve 6 is also moved in the axial direction of the piston 7 and its position is changed. The change-over timing is varied in order to advance the piston 7 in a switching valve 1 by the position change of this flow groove 6a and the stroke length of the piston 7 becomes varied by the change of this timing. The need for equipping a lot of branching passages is obviated by making the stroke of the piston 7 variable by making one flow groove 6a movable like this.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a blowing device in which the stroke length of a piston is variable in order to change the impact energy applied to the object to be crushed, such as a rock, depending on the hardness of the object. It's about tools.

[Conventional technology]

Conventionally, a hammer piston that reciprocates using fluid pressure is provided, and the rear end of a chisel placed at the tip of the hammer piston is struck, and the impact forces the sharp end of the chisel into a rock or concrete wall. A striking tool for crushing this is known.

By the way, the materials to be crushed such as rocks and concrete walls mentioned above have different hardnesses, and the hardness of each type of material varies depending on the type of rock, concrete 1, and material for walls. Among them, some are hard and some are brittle.

Since the impact energy required to crush the hardness differs depending on the hardness, impact tools have been proposed in which the stroke length of the hammer piston is variable so that the impact energy produced by the hammer piston can be adjusted. For example, Japanese Patent Publication No. 54-4882 proposes a control path in which many branch paths are formed to vary the stroke length in stages.

[Problem to be solved by the invention]

However, in the conventional impact tool, as described above, many branching paths must be formed in the control passage, which complicates the machining process and increases manufacturing costs. Also,
The stroke length of the piston can only be set in stages, making it difficult to make subtle adjustments depending on the hardness of the object to be crushed, and this method has the disadvantage that effective crushing cannot be performed. Ta.

[Means to solve the problem]

In order to solve the above-mentioned problem, the impact tool according to the present invention includes a piston that is reciprocably provided in the cylinder for applying impact energy to the actuating tool, and a working fluid supplied by a switching valve is connected to the inner wall of the cylinder. In the impact tool, the screws are reciprocated by appropriately supplying working fluid into each working chamber formed between the piston and discharging working fluid from each working chamber. A sleeve is provided that is fitted onto the piston and moves in the axial direction of the piston to enable position adjustment, and the switching valve is placed in an operating state that allows the piston to move forward when the piston retreats a certain distance. It is characterized in that a flow groove that communicates with the switching valve for switching is formed on the surface of the sleeve that comes into sliding contact with the screws 1 to 1.

[Function] In the above configuration, when the sleeve is moved in the axial direction of the piston and its position is changed, the flow groove formed in this sleeve is also moved in the axial direction of the screw I and its position is changed. is changed. By changing the position of this flow groove, the timing at which the cylinder and screw are switched forward and backward in the switching valve changes, and this change in timing changes the stroke length of the piston. become.

Here, by making only one flow groove movable, the stroke of the piston is made variable, eliminating the need for multiple branch passages as in the past, simplifying the machining process and reducing costs. can be achieved. In addition, since the position of the flow groove is changed steplessly by the movement of the sleeve, the stroke length can be changed steplessly, and the object to be crushed is crushed with impact energy according to the hardness of the object. It becomes possible to improve the efficiency of crushing work.

(Example) An example of the present invention will be described below based on FIGS. 1 and 2.

In the impact tool according to the present invention, as shown in FIG.
In the housing 2 of the switching valve 1, a first circumferential groove 2a, a second circumferential groove 2b, a third circumferential groove 2c, a fourth circumferential groove 2d, and a fifth circumferential groove 20 are formed. A spool 3 having a through hole 3a in the axial direction is provided inside the housing 2 so as to be slidable in the axial direction. On the outer periphery of spool 3,
The first pressure receiving surface A1 forming one wall of the working chamber formed by the fourth circumferential groove 2d, and the fifth circumferential groove 2e.
forming one wall of the working chamber formed by the first
In addition to forming a second pressure receiving surface A2 opposite to the pressure receiving surface A1, a first communication groove 3b capable of communicating the first circumferential groove 2d and the second circumferential groove 2b, and a second circular groove are formed. Circumferential groove 2b and third
A second communication groove 3c that can communicate with the circumferential groove 20 is formed.

Here, the relationship between the respective pressure receiving surfaces is set to satisfy the following first equation.

AI<A2...First formula Also, the third circumferential groove 2c and the fifth circumferential groove 20 in the housing 2 are connected to the hydraulic oil supply section (IN), while the housing 2 and the spool 3 The working chamber formed by the end face of and the first circumferential groove 2a are connected to a return portion (Re1.). Note that the first circumferential groove 2a is connected to a return portion via a throttle valve 4.

The inner wall portion of the cylinder 5 includes a first body portion 5a and a second body portion 5.
b and a sleeve 6, and a piston 7 is fitted within the cylinder 5 formed in this manner and is slidably provided in the axial direction thereof.

The sleeve 6 is provided so as to be movable by a predetermined distance in the axial direction of the piston 7 within the accommodation chamber formed by the first body part 5a and the second body part 5b. A circulation groove 6a is formed in the surface of the sleeve 6 that comes into sliding contact with the piston 7.
It is connected to the. A spring chamber for accommodating the spring 8 is formed between one end of the sleeve 6 and the first main body 5a, while hydraulic oil is provided between the other end and the second main body 5b. A working chamber Y is formed. This working chamber Y is connected to the above-mentioned working oil supply section (I) via a pressure regulating valve 10.
N). The pressure regulating valve 10 is configured to reduce the pressure of the hydraulic oil from the IN and then supply it to the working chamber Y.

A first circumferential groove Z1 and a second circumferential groove Z2 are formed in the first body part 5a, and a third circumferential groove Z3 is formed in the second body part 5b. . The first circumferential groove Z1 is formed in the third circumferential groove 2c of the housing 2, the second circumferential groove Z2 is formed in the fourth circumferential groove 2d, and the third circumferential groove Z3 is formed in the second circumferential groove 2b. each connected.

The piston 7 is formed with a first large diameter portion 7a and a second large diameter portion 7b. When the first large diameter portion 7a is fitted into the circumferential convex portion X formed between the first circumferential groove Z1 and the second circumferential groove Z2 due to the backward movement of the piston 7, the first large diameter portion 7a is inserted into the first circumferential groove Z.
1 and the second circumferential groove Z2, and when the piston 7 is accommodated in the working chamber formed by the first circumferential groove Z1 due to forward movement, the first circumferential groove 71 and the second circumferential groove Z2 are disconnected from each other. It communicates with the circumferential groove Z2.

Further, the second large diameter portion 7b closes the circulation groove 6a due to the forward movement of the piston 7, and the second large diameter portion 7b closes the circulation groove 6a and the second circumferential groove Z.
2, while the backward movement of the piston 7 causes the circulation groove 6a and the second circumferential groove 72 to communicate with each other.

Note that the pressure receiving surface that applies hydraulic pressure in the direction of retracting the piston 7 is the pressure receiving surface B1 of the first large diameter portion 7a or the pressure receiving surface B2 of the second large diameter portion 7b.
The second large diameter portion 7 facing away from the pressure receiving surface B2 acts as a pressure receiving surface that applies hydraulic pressure in the direction of advancing the
This is the pressure receiving surface B3 of b. Here, the relationship between these pressure receiving surfaces is set so as to satisfy the following second equation.

B1=B2<B3...Second formula Note that a chisel 15 as an operating tool is disposed at the impact point position of the piston 7.

In the above configuration, in the state shown in FIG. 1(a), the hydraulic oil manually applied from IN acts on the pressure receiving surface B3 via the third circumferential groove 2c → the first circumferential groove 71, and causes the piston 7 to act on the pressure receiving surface B3. make them retreat. When the piston 7 retreats and the first large diameter portion 7a fits into the circumferential convex portion X, the hydraulic oil acts on the pressure receiving surface B1 and causes the piston 7 to retreat. Note that the hydraulic oil that has passed through the first circumferential groove Z1 is supplied to the fourth circumferential groove 2d via the second circumferential groove Z2 and acts on the pressure receiving surface A1, and the pressure receiving surface that is under the action of the hydraulic oil of the same pressure is Since the pressure receiving surface A1 is larger than the surface A2, the pressure difference maintains the operating state in which the switching valve 1 can move the piston 7 backward.

Further, when the piston 7 is retracted as described above, the hydraulic oil acting on the pressure receiving surface B3 passes through the third circumferential groove 2c → the first circumferential groove 2b → the first circumferential groove 2a, and the flow rate is reduced by the throttle valve 4. It will be returned to the return section with restrictions.

When the piston 7 retreats and the second large-diameter portion 7b releases the flow groove 6a, as shown in FIG. It is returned via the circumferential groove 2d → second circumferential groove Z2 → circulation groove 6a. As a result, the spool 3, which receives the hydraulic oil on the pressure receiving surface A2, moves to the right in the figure, and the switching valve 1 is switched to an operating state in which the piston 7 is moved forward. The hydraulic oil from IN flows from the third circumferential groove 2c to the second circumferential groove 2b to the third circumferential groove.
It acts on the pressure receiving surface B3 through the circumferential groove Z3, and since the pressure receiving surface B3 is larger than the pressure receiving surface B2, which is under the action of the same pressure of hydraulic oil, the repiston 7 starts moving forward due to the differential pressure. do. When the piston 7 starts moving forward and the first circumferential groove Z1 and the second circumferential groove Z2 communicate with each other, the hydraulic oil acts on the pressure receiving surface A1, and until the spool 3 moves to the left in the figure. During this period, the piston 7 moves forward.

The above operations are repeated continuously, and the piston 7 has a stroke length! Move back and forth with 1 and chisel 15
will be hit.

Here, when the hydraulic pressure of the depressurizing regulating oil to the working chamber Y by the pressure regulating valve 10 is further lowered, the sleeve 6 moves toward the left in the figure until it reaches a position where it balances the biasing force of the spring 8, as shown in FIG. 2(a). The flow groove 6a formed in the sleeve 6 also moves to the left in the axial direction of the piston. At this time, the distance from the pressure receiving surface B1 to the right end surface of the circulation groove 6a is as shown in FIG. 1! 1 to 1! , has been extended to 2. Due to the change in the left side position of the circulation groove 6a, the closed state of the circulation groove 6a continues until the piston 7 is moved back further than before, and in the switching valve 1, the timing of switching to move the piston 7 forward is delayed. The stroke length of the piston 7 becomes longer due to this timing delay change.

As described above, the impact tool according to the present invention is capable of making the stroke length of the piston 7 variable by making only one flow groove 6a movable, and there is no need to provide a large number of branch passages as in the past. Since this process is eliminated, the processing process can be simplified and costs can be reduced. Furthermore, since the position of the flow groove 6a is changed steplessly by the movement of the sleeve 6, the stroke length can be changed steplessly, and impact energy corresponding to the hardness of the object to be crushed is applied to the chisel 15. becomes possible.

〔Effect of the invention〕

As described below, the impact tool according to the present invention is provided with a screw for applying impact energy to the working tool in a cylinder so as to be movable back and forth, and a working fluid supplied by a switching valve is connected to the inner wall of the cylinder. In the impact tool, the piston is reciprocated by appropriately supplying working fluid into each working chamber formed between the piston and discharging working fluid from each working chamber, wherein the piston is fitted into the piston within the cylinder. A sleeve is provided to enable position adjustment by moving in the axial direction of the lever piston, and the switching valve is configured to switch the switching valve to an operating state in which the piston can be moved forward when the piston is retracted a certain distance. In this structure, a communicating flow groove is formed on the surface of the sleeve that comes into sliding contact with the piston.

This eliminates the need to provide a large number of branch passages to change the stroke length of the piston, simplifying the machining process and reducing manufacturing costs.

Furthermore, since the position of the flow groove is changed steplessly by the movement of the sleeve, it is also possible to change the stroke length of the piston steplessly.

[Brief explanation of the drawing]

The first and second figures show an embodiment of the present invention. FIG. 1(a) is a Z explanatory view showing the hydraulic circuit configuration of the impact tool, and FIG. 1(b) is an explanatory view showing a state in which the piston is retracted in FIG. 1(a). FIG. 2(a) is an explanatory diagram showing the state in which the sleeve is moving to the left in FIG. 1(a), and FIG.
It is an explanatory view showing a state where the sleeve is moving to the left in Figure (b). 2 is a switching valve, 5 is a cylinder, 6 is a sleeve, 6a is a flow groove, 7 is a piston, and 15 is a chisel (operating tool).

Claims (1)

[Claims] 1. A piston for applying impact energy to a working tool is provided in a cylinder so as to be able to reciprocate, and working fluid supplied by a switching valve is transferred to each cylinder formed between the inner wall of the cylinder and the piston. In the impact tool, the piston is caused to reciprocate by appropriately supplying working fluid into the working chambers and discharging working fluid from each working chamber, wherein the impact tool is fitted with the piston within the cylinder and moves in the axial direction of the piston. a sleeve whose position can be adjusted by the piston, and a flow groove in the sleeve that communicates with the switching valve to switch the switching valve to an operating state that allows the piston to move forward when the piston is retracted a certain distance. A striking tool characterized in that it is formed on the surface of the side that comes into sliding contact with the piston.