JPH02298477A - Stroke tool - Google Patents

Abstract

PURPOSE:To simplify the route of a pressure fluid for adjusting a stroke, to obviate the necessity to consider the leakage of the pressure fluid and to increase the degree of freedom of the layout of the route of the pressure fluid in a housing by arranging a short stroke switching means and a long stroke switching means. CONSTITUTION:At the time of a short stroke mode, a control passage and 1st pressure chamber are communicated via a short stroke switching means 2 according to the retreat from the stroke point of a piston 16 and a spool 12a starts to retreat. When the retreat of this spool 12a is completed, the piston 16 stands still by retreating by the distance equivalent to its average stroke length. At this time, a 2nd pressure chamber is pressurized via the control passage and so the piston 16 starts to advance. The piston 16 is then advanced by the distance equivalent to its averaged stroke length and reaches the stroke point.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an impact tool that transmits impact energy due to the reciprocating motion of screws 1 to 1 in a cylinder to a working tool.

[Conventional technology]

As a conventional example of this type, a hydraulic impact tool disclosed in Japanese Patent Publication No. 54-4882 is known. According to this, the tool has a number of branches with openings into axially spaced apart cylinders of the control channel and is equipped with an adjustment device. These are arranged to selectively close at least one of the branches in order to enable selection of the average stroke length of the hammer piston in the hydraulically actuated impact tool.

With such a configuration, the average stroke length of the hammer piston can be selected, allowing variable adjustment of the stroke. Moreover, the impact energy can be reduced without simultaneously reducing the output of the hydraulically actuated impact tool. Therefore,
Even if the driving pressure is reduced, the output of the tool will not be reduced.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional configuration, the many branch passages of the cylinder are concentrated in the piston drum portion, so that the passage of the pressure nozzle fluid becomes complicated. Moreover, in consideration of leakage of pressure fluid, a distance Pli must be provided between relatively long passages. Therefore, the degree of freedom of the layerer l- of the pressure fluid passage in the housing is reduced. Further, there are problems such as the total length of the tool becomes long and the overall cost increases.

[Means for solving the problem] In order to solve the above problem, the impact tool according to the present invention has the following features:
A housing forming a cylinder, screws 1 to 1 reciprocating within the cylinder and arranged to apply impact energy, and gas formed between the cylinder wall and the screws I, a first pressure chamber with a variable volume that pressurizes the pressure fluid and pushes the piston backward; and a first pressure chamber with a variable volume that pressurizes the pressure fluid and pushes the piston forward, and is formed between the wall of the cylinder and the piston. a stroke adjustment means for changing the average stroke length of the piston between a short stroke mode in which the average stroke length of the piston is short and a long stroke mode in which the average stroke length is long; The spool includes a spool that reciprocates the piston by alternately pressurizing at least one of the first pressure chamber and the second pressure chamber and discharging the pressurized fluid to the discharge path by advancing and retracting the spool. a control passage that connects the cylinder, the switching valve, and the stroke adjusting means by means of pressure fluid; A short stroke switching means formed on the wall of the cylinder communicates the control passage and the first pressure chamber to retract the spool, and in a long stroke mode, the piston retracts backward by a distance corresponding to its average stroke length. 1. A long stroke switching means is provided on the wall of the cylinder to advance the spool by communicating the control passage and the pressure fluid discharge passage so that the piston advances.

[For production]

According to the above configuration, the piston within the cylinder reciprocates with a different average stroke length depending on the switched mode, as the spool within the switching valve alternately moves forward and backward. Impact energy associated with this reciprocating motion is transmitted to the actuating tool.

For example, in the short stroke mode, as the piston retreats from the impact point, the control passage and the first pressure chamber communicate with each other via the short stroke switching means, and the spool begins to retreat. When the spool has finished retracting, the piston moves back a distance corresponding to its average stroke length and comes to rest. At this time, the second pressure chamber is pressurized via the control passage, so the piston begins to move forward. During this forward movement, the spool begins to move forward. The piston then moves forward by a distance corresponding to its average stroke length and reaches the point of impact.

On the other hand, in the long stroke mode, when the piston starts to retreat from the impact point, the spool does not retreat and remains stationary by the stroke adjustment means. Accordingly, the piston does not come to rest even if it retreats to a distance equivalent to the average stroke length in short stroke mode, but continues to retreat, and it retreats by a distance equivalent to the average stroke length in long stroke mode and comes to rest. do. At this time, the control passage and the discharge passage communicate with each other via the long stroke switching means, so that the spool retreats. At the same time, the second pressure chamber is pressurized and the piston also begins to move forward. During this forward movement, the spool begins to move forward. The piston then advances by a distance corresponding to its average stroke length and reaches the point of impact.

By repeating the above operations, the impact energy accompanying the reciprocating movement of the piston is transmitted to the actuating tool in the short stroke mode or in the long stroke dry mode.

[Example] An example of the present invention will be described below with reference to FIGS. 1 to 4.

As shown in FIG. 1, the impact tool according to the present invention mainly comprises a stroke adjustment valve 11 as stroke adjustment means, a switching valve 12, a cylinder 13, and a piston 16.

The stroke adjustment valve 11 switches a control passage connected between a short stroke mode in which the average stroke length of the piston 16 is short and an I:Ings l−+d+h mode in which the average stroke length is long. By this switching, the average stroke length of the piston can be varied for each mode.

For example, in the short stroke mode, as shown in FIG. 1, one end of the valve 11c and one end of the valve 11cl are both connected to a boat 10 of a switching valve 12, which will be described later, and a boat 9 is connected to the other end of the valve 11c. Concatenated. valve lid
The other end is connected to the outlet of the flow rate regulating valve 23 and further connected to the drainage channel 22 . Flow rate adjustment valve 23, supply passage 2
The pressure is adjusted so as not to reduce the pressure of the pressure fluid from 1. Note that the valve 11c is always closed, and pressure fluid cannot pass through it. Also, the valve lid is always open, allowing pressure fluid to pass through it. The boat 10 thus communicates directly with the drainage channel 22.

Further, in the long stroke mode, one end of the valve 11a and one end of the valve 11b are both connected to the boat 10.

The other end of the valve 11a is connected to the boat 9. The other end of the valve 11b is connected to the drainage channel 22. Note that the valve 11a is always open, allowing pressure fluid to pass through it. Also, the valve 11b is always closed and no pressure fluid can pass through it. By the way, switching between short stroke mode and long stroke mode may be performed manually. Further, the above mode switching may be performed using an external pilot method.

The switching valve 12 is a first valve in a housing (not shown).
The piston 16 is alternately pressurized by pressurizing at least one of the second pressure chamber and the second pressure chamber, and discharging the pressurized fluid from this to the drainage channel 22 by moving the piston 16 forward and backward.
is moving back and forth. Note that the above-mentioned first pressure chamber includes the cylinder 13, the rod portion 16b1 of the piston 16, the piston portion 14, and the boat 1 or Jotos! - Limited by the front of the boat 2 as a loaf switching means.

Further, the second pressure chamber is defined by the cylinder 13, the rod portion 16a of the piston 16, the piston portion 15, and the rear surface of the boat 6.

The switching valve 12 has a boat 7, a boat 8, a boat 9, and a boat 10 formed in a wall portion 12b of its cylinder in order from the front side. The boats 1 to 7 are connected to a boat 6 formed on the wall of the cylinder 13, which will be described later. The boat 7 pressurizes and discharges the pressure fluid in the second pressure chamber depending on the state of communication with the boat 8. for example,
When the boats 1 to 7 communicate with the boat 8, the pressure fluid in the second pressure chamber is discharged to the drainage channel 22. On the other hand, boat 7
When the bows 1-8 are no longer in communication with each other, high-pressure fluid is supplied from the supply passage 21 to the second pressure chamber. Bow 1-
9 and boat 10 control the reciprocating movement of a spool 12a, which will be described later, by pressurizing or discharging the pressure fluid therein. Boat 9 is connected to boat 3. The boat 10 is connected to a boat 5 serving as long stroke switching means.

In the switching valve 12, the spool 12a that opens and closes each bow I.
A concave notch 12c is formed in the bottom wall of the spool 12a so that the boat 7 and the boat 8 can communicate when point a is at the front end. The cross-sectional area of the front end surface of the spool 12a is A1. Further, the spool 12a is connected to the boat 9.
A convex protrusion 12d that reciprocates between the boat 1o and the boat 1o is formed on its outer wall.

The cross-sectional area of the front end surface of the projection 12d is 83. The cross-sectional area of the rear end surface of the protrusion 12d is A4. Spool 12
The cross-sectional area of the rear end surface of a is A2. to cross-sectional area, ~A4
The relationships expressed by the following equations (1) to (3) hold true between them.

A, >81... (1) Eight. <
A I+ A 3... (2)
A2+A4-81→-Δ3...
(3) The protrusion 12d is formed so as not to move backward by -1 beyond the boat 10.

The piston 16 is arranged in an invisible housing forming the cylinder 13 so as to reciprocate within the cylinder 13 and transmit its impact energy to the actuating tool 17 . The cylinder 13 is not limited to a true cylindrical shape, and may be, for example, a one-stage cylinder. In the sheath r-1' sheath 1-loak mode, the piston 16 reciprocates by a distance i@If ffi corresponding to its average stroke length, as shown in FIG. Also, in the long stroke mode, as shown in Figure 4,
It reciprocates by a distance of 2 degrees corresponding to the average stroke length of 4.11. The piston 16 has a piston part 15 having a screw I/n face 18 and a piston part 1 having a piston face 2°.
It consists of a cylindrical rod with 4. The relationship expressed by the following equation (4) holds between the area a of the piston surface 18 and the area a1 of the piston surface 20 in item 1.

a2>a, ... (4) The part of the piston extending rearward from the piston part 15 is the rod part 16a.
It is indicated by. Also, a portion of the screw I/N extending forward from the piston portion 14 is indicated by a rod portion 16b. Between the piston portion 14 and the piston portion 15 is a rod portion 16c.
It is indicated by.

As shown in FIG. 1, on the wall 13a of the cylinder 13,
Boats 1 to 6 are formed in order from the impact point P side. Boat 2 and boat 3 are connected. The boat 1 is formed so as to always communicate with the first pressure chamber. The boat 2 is formed so that when it communicates with the boat 1, high pressure fluid from the supply passage 21 flows into the boats 1-9, causing the spool 12a to retreat rearward. The boat 4 is connected to a drainage channel 22. Boat 3 is
When connected to the boat 4, the boat 9 is connected to the drainage channel 22 so that the spool 12a moves forward. It should be noted that the boat 3 is formed so that it no longer communicates with the boat 4 when the boat 1 and the boat 2 communicate with each other.

The boat 5 is formed so that, when communicating with the boat 4 in the long stroke mode, the boat 10 communicates with the drainage channel 22 to advance the spool 12a. The bow 16 is configured to introduce high pressure pressure fluid from the supply passage 21 via the boat 7 into the second pressure chamber.

In the above configuration, the piston 16 in the cylinder 13 performs a reciprocating motion with a different average stroke length for each switched mode I' as the switching valve 12 moves forward and backward alternately. The impact energy associated with this reciprocating motion is
It is transmitted to the actuating tool 17.

For example, the operation of the short stroke moat will be explained below based on FIGS. 1 and 2.

In the show 1 to 1, the valves 11c and 11d in the stroke adjustment valves 11 are connected to the control passage 1, as shown in the first episode. Below, piston 1
The backward movement of No. 6 will be explained.

As shown in FIG. 1, when the front surface of the rod portion 16b of the piston 16 is in contact with the striking point P, the spool 12a in the switching valve 12 is located at the front end. At this time, since the boats 1-7 and 8 are communicating with each other, the pressure fluid in the second pressure chamber (not shown) flows through the boats 6, 7,
It is discharged to the drainage channel 22 via the bows I to 8 and the flow rate adjustment valve 23. The boat 1 is supplied with high pressure fluid from the supply passage 21, which is applied to the piston surface 20 having an area a1.
It acts on Therefore, the piston 16 begins to retreat rearward. When the boats 1 and 2 are brought into communication with this retreat, pressure fluid from the supply passage 21 is supplied to the boats 1, 2, and 9, and is applied to the area of the protrusion 12d of the spool 12a. It acts on the part. On the other hand, the boat 10 is always connected to the drainage channel 22 via the valve lid in the flow control valve 11. Therefore, the spool 12a begins to retreat rearward and comes to rest at the position shown in FIG. The piston 16 also has a distance 1 corresponding to its average stroke length.
It retreats by 1 from the impact point P and comes to rest. The forward movement of the piston 16 will be explained below.

As the switching valve 12 moves backward, the boat 7 no longer communicates with the boat 8. The high-pressure fluid from the supply passage 21 is supplied to the boat 7 and further via the boat 6 to the second
is supplied to the pressure saw chamber. High-pressure fluid is supplied to both the second pressure chamber and the first pressure chamber, but the piston 16 moves toward the impact point P due to the pressure-receiving area relationship shown in equation (4) above. move forward toward

When the piston 16 moves forward and the boats 3 and 4 communicate with each other, the boats I and 9 communicate with the drainage channel 22 via the boats 3 and 4, so that the spool 12a starts moving forward. Piston 16 is the distance! 1 When you move forward, the screw I/N1
The front surface of 6 reaches the impact point P and impacts the actuating tool 17.

At this time, as shown in FIG. 1, high pressure fluid is supplied to a first pressure chamber (not shown) via the boat 1. At the same time, the boats 7 and 8 communicate with each other, and the high pressure fluid in the second pressure chamber is transferred to the boats 6, 7, boats 1 to 8.
B and is discharged to the drainage channel 22 via the flow rate adjustment valve 23.

Therefore, the piston 16 begins to retreat as described above.

The above-described operations are repeated to perform the batting operation in the short stroke mode.

Next, the operation in long stroke mode is explained in the third section.
The explanation based on the figures and FIG. 4 is as follows.

In the long stroke mode, valves 11a and llb in the stroke adjustment valve 11 are connected to the control passage, as shown in FIG. The retreating movement of the piston 16 will be explained below.

When the front surface of the rod portion 16b is in contact with the striking point P, the spool 12a is stationary at the front end position, as shown in FIG. At this time, since the boats 7 and 8 are in communication, the pressure fluid in the second pressure chamber is transferred to the drain channel 2 through the boats 6, 7, 8, and the flow rate adjustment valve 23.
It is discharged to 2. On the other hand, high-pressure fluid is supplied to the boat l from the supply passage 21, which acts on the piston surface 20 having an area a1. Therefore, the piston 16 begins to retreat rearward.

When boat 1 and boat 2 communicate with each other due to this retreat, high-pressure fluid is supplied from supply passage 21 to boat 1, boat 2, and boat 9, and is applied to a portion of area Δ3 of protrusion 12d. act. On the other hand, high-pressure fluid is also supplied to the hole 0 from the supply passage 21 via the hole 0, the boat 2, and the valve 11a in the stroke adjustment valve 11. As described above, high pressure fluid is supplied to the boats 9 and boats I and 10 at the same time, so the spool 12a remains stationary at the position shown in FIG. 3 without moving forward or backward. . During this time, the piston 16 continues to move backward beyond the distance 21 in the show 1 to stroke modes. Then, when the piston 16 retreats from the striking point P by a distance P2 corresponding to the average stroke length in the long stroke mode, the boats 4 and 5 communicate with each other. The forward movement of the piston 16 will be explained below.

The high pressure fluid in boat 10 is discharged to drainage channel 22 via boats 1-5 and boat 4. Along with this,
The spool 12a begins to retreat rearward and comes to rest at the position shown in FIG. When the boats 7 and 8 are no longer communicated with each other, high pressure fluid from the supply passage 21 is supplied to the second pressure chamber via the boats 1 to 7 and the boat 6. At this time, high pressure fluid is also supplied to the first pressure chamber from the supply passage 21 via the boat 1, but due to the relationship of pressure receiving area (area a2>area a), the piston 16 is placed at the impact point. Start moving towards P. piston 1
6 moves forward and the boats 3 and 4 communicate with each other, the boats 1 to 9 are connected to the drainage channel 22 via the boats 3 and 4.
, the spool 12a has a pressure receiving area (area A2
＞To the area, start moving forward according to the relationship ).

When the boats 7 and 8 communicate with each other, the front surface of the piston 16 strikes the operating tool 17 at the striking point P. At this time, as shown in FIG. 3, the boat 1 and the boat 2 communicate with each other, and high pressure fluid is supplied to the first pressure chamber. At the same time, the pressure fluid in the second pressure chamber flows through the boat 6, the boat 7, the boat 8, and the flow rate adjustment valve 23 to the drain channel 2.
2, the piston 16 begins to retreat as described above. The above-described operations are repeated to perform the hitting operation in the long stroke mode.

〔Effect of the invention〕

The impact tool according to the present invention includes a housing that forms a cylinder, a piston that reciprocates within the cylinder and provides impact energy, and a wall of the cylinder and screws. 1 to 1, and
A first pressure chamber with a variable volume that pressurizes pressure fluid to push the piston backward, and a volume that is formed between the cylinder wall and the screws 1 to 1 and pressurizes the pressure fluid to push the piston forward. In the impact tool equipped with a variable second pressure chamber, the jawtos I-shear 2- has a short average stroke length of the piston.
stroke adjustment means for changing the average stroke length of the screws 1 to 1 in the long stroke mode and the long average stroke length; and pressurization of at least one of the first pressure chamber and the second pressure chamber. and a switching valve equipped with a spool that reciprocates a piston by alternately advancing and retracting the pressure fluid and discharging the pressure fluid into a discharge path; - a control passage that communicates the pressure adjustment means with a pressure fluid; and a first pressure chamber that communicates with the control passage so that the piston retreats rearward by a distance corresponding to its average stroke length in the short stroke mode. A stroke switching means is formed on the wall of the cylinder for retracting the C spool, and the piston is configured to move forward after the piston has retreated backward by a distance corresponding to its average stroke length in the long stroke mode. This configuration includes long stroke switching means formed on the wall of the cylinder that communicates the control passage and the pressure fluid discharge passage to advance the spool.

This simplifies the pressure fluid path for stroke adjustment. Moreover, there is no need to take pressure fluid leakage into consideration, and the degree of freedom in layout of the pressure fluid path in the housing increases. Further, the overall length of the tool can be shortened, and the overall cost can be reduced as well.

[Brief explanation of the drawing]

1 to 4 show one embodiment of the present invention. FIG. 1 is a diagram showing the forward movement of the piston during short stroke mode. FIG. 2 is a diagram showing the retraction operation of the piston during the short stroke mode. FIG. 3 is a diagram showing the retracting operation of the piston when the spool is in a stationary state in the long stroke mode. FIG. 4 is a diagram showing the retraction operation of the piston in the long stroke mode. 2 is a boat (Jotos 1 to Roke switching means), 5
11 is a stroke adjustment valve (stroke adjustment means), 12 is a switching valve, 13 is a cylinder, and 16 is a piston.

Claims (1)

[Claims] 1. A housing that forms a cylinder; a piston that reciprocates within the cylinder and is arranged to apply impact energy; and a housing that is formed between the wall of the cylinder and the piston, and , a first pressure chamber with a variable volume that pressurizes the pressure fluid and pushes the piston backward; and a first pressure chamber with a variable volume that pressurizes the pressure fluid and pushes the piston forward; a stroke adjustment means for changing the average stroke length of the piston between a short stroke mode in which the average stroke length of the piston is short and a long stroke mode in which the average stroke length is long; , a spool that reciprocates the piston by alternately pressurizing at least one of the first pressure chamber and the second pressure chamber and discharging the pressurized fluid to the discharge path by advancing and retracting the spool; a control passage that communicates the cylinder, the switching valve, and the stroke adjustment means with pressurized fluid; and a control passage that allows the piston to retreat rearward by a distance corresponding to its average stroke length in a short stroke mode. and a short stroke switching means formed on the wall of the cylinder that communicates with the first pressure chamber and retracts the spool; and in the long stroke mode, after the piston has retreated backwards by a distance corresponding to its average stroke length; A striking tool comprising: long stroke switching means formed on a wall of a cylinder that communicates a control passage and a pressure fluid discharge passage to advance a spool so that the piston advances.