JP2003191143A - Cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting tool capable of rapidly and stably an advancing/ retreating action of an aperture-machining tool mounted to a tool body and efficiently carrying out a cutting work. <P>SOLUTION: The cutting tool S is provided with a tool body 1 rotating around an axis O; an aperture machining tool 2 mounted to the tool body 1; and a moving mechanism K for moving the aperture machining tool 2 to a direction along the axis O. The moving mechanism K is provided with a piston 8 movable in a piston chamber 6 of the tool body 1; a fluid feed part 12 for feeding a fluid to a first space 6a, in the piston chamber 6, formed at a rear end side of the piston 8 and a second space 6b formed at a tip end side respectively; and a second piston 20 for switching a fluid feed action against each of the first space 6a and the second space 6b. The second piston 20 carries out a switching action in responsive to the revolution number per unit time of the tool body 1. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting tool, and more particularly to a cutting tool suitable for machining a valve hole in a cylinder head of an engine.

[0002]

2. Description of the Related Art In a valve hole of a cylinder head,
Since the valve frequently hits the periphery of the opening of the valve hole,
In order to improve durability, a hard member such as a sintered alloy is generally fitted around the opening. When processing such a valve hole of a cylinder head, a cutting tool provided with a hole processing tool such as a gun reamer for finishing the hole itself and a cutting edge tip for processing the peripheral edge of the opening is used.

FIG. 4 shows an example of a conventional cutting tool for machining a valve hole of a cylinder head. Figure 4
In Fig. 1, the cutting tool SJ includes a cutter body (tool body) 51a formed in a substantially conical shape, and an adapter (tool body) 51b arranged between a cutter body 51a and a spindle end of a machine tool (not shown). Is equipped with. Cutter body 51a
Is provided with a bush 53 along the axis O, and a hole drilling tool 52 such as a gun reamer is fitted into the bush 53. A plurality of cutting blade tips 54 (one in the figure) are slidably provided along the generatrix on the outer circumference of the conical cutter body 51a. And the cutting tool S
The J is mounted on a machine tool so as to rotate about the axis O. Here, in the following description, the cutter body 51a and the adapter 51b connected to the cutter body 51a are collectively referred to as a tool body 51,
The side to which the hole drilling tool 52 is attached is referred to as a front end A, and the side to be attached to a machine tool is referred to as a rear end B.

A piston chamber 56 is formed inside the tool body 1, and a hole drilling tool 52 is formed in the piston chamber 56.
A piston 58 that is connected to the rear end and is capable of reciprocating in the direction of the axis O is arranged. A guide rod 59 is provided in the piston chamber 56, and the piston 58 reciprocates in the direction of the axis O while being guided by the guide rod 59.

A collar 60 is arranged on the rear end side of the bush 53, and a spring 63 is provided between the collar 60 and the piston 58. The spring 63 has a tip end side supported by the collar 60 and a rear end side abutted on the piston 58, and is contracted when the piston 58 is moving to the tip end A side. That is, when the piston 58 is moving to the front end A side, the spring 63 biases the piston 58 toward the rear end B side.

On the rear end B side of the piston chamber 56, there is connected a fluid supply portion 62 capable of supplying a fluid (oil or air) to a space 56A formed in the piston chamber 56 on the rear end B side of the piston 58. Has been done. From the fluid supply unit 62 to the space 5
By supplying a predetermined amount of fluid to 6A, the piston 58 is moved to the tip A side by the action of pressure based on the supplied fluid.

Next, a cutting tool SJ having the above-mentioned structure
A method of processing a valve hole by means of will be described with reference to the schematic view of FIG. First, the hole drilling tool 52 is inserted into the bush 53, and the rear end of the hole drilling tool 52 and the piston 58 are inserted.
And connect. Next, as shown in FIG. 5A, the hole drilling tool 52 is pulled toward the rear end B side of the tool body 51. The drawing of the hole drilling tool 52 toward the rear end B side is performed by the action of the spring 63 having an urging force toward the rear end B side. That is, the piston 58 moves to the rear end B side by the urging force of the spring 63 toward the rear end B side, and with the movement of the piston 58 to the rear end B side, the hole drilling tool connected to the piston 58. 52 also moves to the rear end B side and is drawn into the tool body 51. Then, while the hole drilling tool 52 is pulled toward the rear end B side, the tool main body 51 is rotated and is fed to the front end A side along the axis O, so that a plurality of holes are provided on the outer periphery of the front end of the tool main body 51. A predetermined cutting blade tip 54 of the cutting blade tips 54 chamfers the opening of the valve hole. Further, the other cutting edge tip 54 is provided slidably along the generatrix of the tip of the tool body 51. After chamfering, the entire cutting tool SJ is temporarily moved slightly to the rear end B side, and then the tool body By sliding the cutting edge tip 54 while rotating 51, a tapered surface is formed at the peripheral edge of the opening portion of the valve hole.

Next, as shown in FIG. 5 (b), the entire cutting tool SJ is once moved to the rear end B side, and then the hole boring tool 52 is projected to the tip A side while rotating the tool body 51. Move to let. At this time, when the hole machining tool 52 is moved toward the tip A side, the fluid supply unit 62 moves the piston chamber 56.
This is performed by supplying a predetermined amount of fluid to the space 56A. That is, the fluid supply unit 62 supplies the fluid to the space 56A to increase the pressure in the space 56A, and the piston 58 moves to the tip A side based on this pressure increase, and moves to the tip A side of the piston 58. Along with the movement of, the hole drilling tool 52 connected to the piston 58 moves to the tip A side. Here, the amount of fluid supplied to the space 56A is set so that the pressure of the space 56A based on the supplied fluid is larger than the urging force of the spring 63 toward the rear end B side of the piston 58.

Then, as shown in FIG. 5 (c), the hole drilling tool 52 is rotated in a state of being projected toward the tip end side of the tool body 51, and the entire cutting tool SJ is fed to the tip end A side, so that the valve hole The inside of (the valve guide hole) is finished.

[0010]

As described above, the withdrawal operation of the hole drilling tool 52 from the tool main body 51 is based on the movement of the piston 58 arranged in the piston chamber 56 inside the tool main body 51. The movement of the piston 58 to the tip A side is due to the pressure increase in the space 56A based on the fluid supplied from the fluid supply unit 62 to the space 56A, while the piston 58 is moved to the rear end B side. The move is
This is due to the biasing force of the spring 63. That is,
When moving the piston 58 to the tip A side, the fluid supply unit 62
Although the moving speed and the moving amount can be controlled by adjusting the amount of fluid supplied per unit time and adjusting the pressure in the space 56A, when the piston 58 is moved to the rear end B side, the movement is caused by the spring 63. Since it is based on power, it may become unstable (irregular) such as the movement speed slowing down or stopping halfway.
As described above, the conventional cutting tool SJ has a problem that the movement operation of the hole drilling tool 52 connected to the piston 58 toward the rear end B side becomes unstable (irregular).

The present invention has been made in view of the above circumstances, and provides a cutting tool capable of performing a retracting operation of a hole drilling tool attached to a tool body quickly and stably and performing a cutting operation efficiently. The purpose is to provide.

[0012]

In order to solve the above-mentioned problems, a cutting tool according to a first aspect of the present invention includes a tool body that rotates around a predetermined axis, a hole drilling tool that is attached to the tool body, In a cutting tool including a moving mechanism that moves a hole drilling tool in a direction along the axis to move the tip of the hole drilling tool out of the tool body, the moving mechanism is formed inside the tool body. A piston that is movably provided in the axial direction in a chamber and is connected to the rear end of the hole drilling tool, and a first space and the piston that are formed on the axial rear end side of the piston in the chamber. A fluid supply part capable of supplying a fluid to each of the second spaces formed on the tip side in the axial direction of the, and a fluid supply part to each of the first space and the second space by the fluid supply part. And a switching device for switching the operation, the switching device, and performs a switching operation in accordance with the number of revolutions per unit time of the tool body.

According to the present invention, there is provided an axially movable piston in the chamber formed inside the tool body,
Since the fluid is independently supplied to each of the first space formed on the rear end side of the piston and the second space formed on the front end side of the chamber by using the switching device, the first space is formed. By supplying the fluid to the space, the pressure in the first space is increased to move the piston to the tip side, the hole drilling tool connected to this piston can be moved to the tip side, and the fluid is supplied to the second space. Second by doing
The hole drilling tool can be moved to the rear end side by increasing the pressure in the space. Since the switching device performs the switching operation according to the number of rotations of the tool body, the hole drilling tool can be moved to the tip side by rotating the tool body at high speed when performing hole drilling, and rotate at low speed. As a result, the hole drilling tool can be moved to the rear end side. In this way, the boring tool can be moved in and out simply by adjusting the number of rotations of the tool body per unit time. Therefore, the retracting operation of the hole drilling tool attached to the tool body can be quickly and stably performed, and the cutting work can be efficiently performed.

A cutting tool according to a second aspect is the cutting tool according to the first aspect, wherein a main flow path connected to the fluid supply portion and a main flow path branched from a middle portion thereof are connected to the first space. A second flow path that branches from the middle of the main flow path and connects to the second space; and the switching device connects to the first flow path and the second flow path. A second piston is provided in the piston chamber so as to be movable in a direction intersecting with the axis in accordance with the number of rotations of the tool body per unit time, and by the movement of the second piston, the first flow path and the One of the second flow paths is blocked.

According to the present invention, the switching device is provided with the second piston that moves in the direction intersecting the axis according to the number of revolutions of the tool body per unit time. It is possible to block either one of the first flow path connecting the first space and the first space and the second flow path connecting the fluid supply unit and the second space. Therefore, it is possible to easily and quickly switch the supply of the fluid to each of the first space and the second space.

A cutting tool according to a third aspect is the cutting tool according to the second aspect, wherein the second flow path is shut off when the number of rotations of the tool body per unit time exceeds a predetermined value, and the tool is cut. The first flow path is shut off when the number of rotations of the main body per unit time becomes less than a predetermined value.

According to the present invention, the switching device is set to shut off the second flow passage when the rotation speed becomes high and shut off the first flow passage when the rotation speed becomes low. In particular,
The second piston moves in a direction toward and away from the axis line by a centrifugal force according to the number of rotations of the tool body per unit time, thereby blocking and opening each of the first flow path and the second flow path. It is set to be performed, and the switching operation of the fluid supply to the first space and the second space can be easily performed with a simple configuration.

A cutting tool according to a fourth aspect is the cutting tool according to the third aspect, further comprising an urging member for urging the second piston in a direction of approaching the second piston with respect to the axis line. When the number of rotations per unit time becomes equal to or more than a predetermined value, the second piston moves in a direction away from the axis to block the second flow passage, and the number of rotations per unit time of the tool body is changed. When it becomes less than a predetermined value, the urging member moves the second piston in a direction approaching the axis to block the first flow path.

According to the present invention, the urging member for urging the second piston in the direction of approaching the axis is provided, so that when the rotational speed of the tool body is low, the second member is urged by the urging force of the urging member. The piston is arranged at a position that blocks the first flow path, and when the rotation speed is high, the centrifugal force of the second piston overcomes the biasing force of the biasing member and the second piston blocks the second flow channel. Will be placed. Here, the predetermined value is the rotation speed of the tool body per unit time when the centrifugal force of the second piston becomes equal to the urging force of the urging member, and the rotation speed per unit time is equal to or more than the predetermined value. When the main body rotates, the centrifugal force of the second piston exceeds the urging force of the urging member, and when the tool body rotates at a rotation speed per unit time less than a predetermined value, the centrifugal force of the second piston is urged. Less than the urging force of.

[0020]

DETAILED DESCRIPTION OF THE INVENTION A cutting tool of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of the cutting tool S of the present invention. Here, the cutting tool S in this embodiment is used when processing the valve hole of the cylinder head.

In FIG. 1, a cutting tool S has a tool body 1 rotating around a predetermined axis O, a hole drilling tool 2 attached to the tool body 1, and a hole drilling tool 2 moved in a direction along the axis O. And a moving mechanism K. The tool body 1 is composed of a cutter body 1a formed in a substantially conical shape, and an adapter 1b arranged between the cutter body 1a and a spindle end of a machine tool (not shown). A bush 3 is provided inside the tool body 1 along the axis O, and a hole drilling tool 2 such as a gun reamer is fitted into the bush 3. A plurality of cutting blade tips 4 (one in the figure) are slidably provided along the generatrix on the outer circumference of the conical cutter body 1a. And the cutting tool S
Is mounted on a machine tool so as to rotate about the axis O. Here, in the following description, the side to which the hole drilling tool 2 is attached (the cutter body 1a
The side) is the front end A, and the side attached to the machine tool (the adapter 1b side) is the rear end B.

A piston chamber 6 is formed inside the tool body 1, and a piston 8 connected to the rear end of the hole drilling tool 2 and reciprocally movable in the direction of the axis O is arranged in the piston chamber 6. ing. A guide rod 9 is provided inside the piston chamber 6, and the piston 8 reciprocates in the direction of the axis O while being guided by the guide rod 9.

A first space 6a (see FIG. 2) is formed at the rear end side of the piston 8 reciprocating in the piston chamber 6 in the direction of the axis O, and a second space 6b is formed at the front end side. ing. The piston chamber 6 is provided with a fluid supply unit 12 capable of supplying fluid to each of the first space 6a and the second space 6b of the piston chamber 6.
5 and the first and second flow paths 15a and 15b. Further, the fluid supply unit 12 includes the fluid supply unit 1
A control device CONT for controlling the operation of No. 2 is connected. Specifically, the control device CONT includes the fluid supply unit 12
The liquid supply amount per unit time supplied from the to the piston chamber 6 is controlled. Here, in the present embodiment,
The fluid supply unit 12 supplies oil to the piston chamber 6, and the piston chamber 6 is a hydraulic chamber.
The fluid supply unit 12 may supply gas such as air to the piston chamber 6.

A main channel 15 is connected to the fluid supply unit 12. The main flow path 15 has an axis O on the rear end side of the tool body 1.
The fluid supplied from the fluid supply unit 12 first flows through the main flow path 15. The main flow path 15 is divided into a first flow path 15a and a second flow path 15b from the middle on the outer rear end B side of the piston chamber 6.
The first flow path 15a is the first space 6a of the piston chamber 6.
And the second flow path 15b is connected to the second space 6 of the piston chamber 6.
connected to b.

Here, two first flow paths 15a (two systems) are provided so as to face each other with the axis O interposed therebetween. Similarly, the two second flow paths 15b are provided so as to face each other with the axis O interposed therebetween (two systems). Therefore, the fluid is supplied to the first space 6a from the two first flow paths 15a, and the fluid is supplied to the second space 6b from the two second flow paths 15b. It is like this.

The tool body 1 has a second piston chamber 21 connected to each of the first flow passage 15a and the second flow passage 15b branched from the main flow passage 15. Two second piston chambers 21 are also provided. As shown in the enlarged view of FIG. 3, the second piston chamber 21 includes the first flow passages 15 arranged in parallel.
It is formed so as to straddle each of a and the second flow path 15b. The fluid that has flowed from the main flow path 15 to the first flow path 15a passes through the second piston chamber 21 and then flows into the first space 6a.
Is supplied to. Similarly, from the main flow path 15 to the second flow path 15b
The fluid that has circulated through the second piston chamber 21 is supplied to the second space 6b.

In the second piston chamber 21, a second piston (switching device) 20 is provided which is movable inside the second piston chamber 21 in a direction intersecting with the axis O. The second piston 20 has an internal flow path 24.
As shown in FIG. 3, the internal flow path 24 includes the second piston 20.
Is formed so as to penetrate in the direction of the axis O.

Then, as shown in FIG. 3A, when the second piston 20 moves in a direction approaching the axis O,
The peripheral wall surface 20a of the second piston 20 closes the connection port k1 between the first flow path 15a and the second piston chamber 21, and the first flow path 1
5a is cut off. At this time, the second flow passage 15b allows the fluid to flow through the internal flow passage 24 of the second piston 20.

On the other hand, as shown in FIG. 3 (b), when the second piston 20 moves in the direction away from the axis O, the peripheral wall surface 20b of the second piston 20 forms a second flow path 15b and a second flow path 15b.
By closing the connection port k2 with the piston chamber 21, the second flow path 15
b is cut off. At this time, the first flow path 15b allows the fluid to flow through the second piston chamber 21.

As described above, the second piston 20 reciprocates in the second piston chamber 21 in the direction intersecting with the axis O so that the second flow passage 15b is not connected when the first flow passage 15a is in the connected state. When the connection state is established and the second flow path 15b is established, the first flow path 15a is disconnected. And
Depending on the reciprocating movement of the second piston 20, the fluid from the main flow passage 15 is supplied to the first space 6a via the first flow passage 15a or to the second space 6b via the second flow passage 15b. It is supposed to be done. That is, by the reciprocating movement of the second piston 20, the liquid supply operation of the liquid supplied from the liquid supply unit 12 via the main flow path 15 to each of the first space 6a and the second space 6b can be switched. .

An end surface of the second piston 20 opposite to the axis O (that is, an outer end surface of the second piston 20).
A spring (biasing member) 23 is arranged at 20b. This spring 23 is provided on the end face 2 of the second piston 20.
0b, the groove is formed in a U-shape in cross section, and is disposed between the stopper member 25. Stopper member 25
Is provided with a male screw groove 26a capable of being screwed into a female screw groove 26b of a through hole formed in a direction intersecting with the axis O so as to connect the outside of the tool body 1 and the second piston chamber 21,
By screwing the male screw groove 26a and the female screw groove 26b into each other, the position of the stopper member 25 in the direction intersecting the axis O is adjusted, and the elastic deformation amount of the spring 23 between the stopper member 25 and the second piston 20 is adjusted. Can be adjusted. Then, by adjusting the elastic deformation amount of the spring 23, the second
The urging force on the piston 20 can be adjusted.

Here, the spring 23 allows the second piston 20 to move even when the second piston 20 is moving away from the axis O, that is, as shown in FIG.
Even when the inner end surface 20c of 0 and the inner wall surface of the second piston chamber 21 are in contact with each other, they are deformed so as to be contracted. That is, the second piston 20 is the second piston chamber 2
The spring 23 in FIG. 1 is biased in a direction to approach the axis O.

Next, the operation of the cutting operation using the cutting tool S having the above structure will be described. In addition,
Since the actual cutting procedure is the same as the procedure described with reference to FIG. 5, the description thereof will be omitted below. First, the hole drilling tool 2 is inserted into the bush 3, and the rear end of the hole drilling tool 2 and the piston 8 are connected. In addition, here, the diameter of the most distal end portion 2a (see FIG. 1) of the hole drilling tool 2 is such that the rear end B is larger than the most distal end portion 2a.
It is set to be smaller than the side finish cutting portion 2b. By doing this, when performing hole finishing, the tip 2a
After finishing with a predetermined accuracy, the finishing cutting section 2b can finish with high accuracy.

In the state before finishing the inside of the valve hole, the fluid supply unit 12 supplies a predetermined amount of fluid to the main flow path 15 per unit time under the control of the controller CONT. At this time, the tool body 1 of the cutting tool S is not rotating, and the second piston 20 is moved in the direction approaching the axis O by the urging force of the spring 23. Therefore, the fluid supplied from the fluid supply unit 12 to the main flow path 15 is the second fluid as shown in FIG. 1 and FIG.
It is supplied to the second space 6b of the piston chamber 6 through the flow passage 15b and the internal flow passage 24 of the second piston 20. The second space 6b supplied with a predetermined amount of fluid per unit time,
The action of the pressure based on the supplied fluid moves the piston 8 to the rear end B side. Here, the amount of fluid supplied per unit time from the fluid supply unit 12 to the second space 6b of the piston chamber 6 increases the pressure in the second space 6b,
This is a predetermined amount sufficient to move the piston 8 to the rear end B side. This predetermined amount is obtained in advance by experiments or the like. Therefore, as shown in FIG. 1, when the tool body 1 is not rotating, the hole drilling tool 2 connected to the piston 8 is immersed in the tool body 1.

When the tool body 1 is rotated to finish the inside of the valve hole, the second piston 20 tends to move away from the axis O by the centrifugal force based on the rotation of the tool body 1. Then, when the number of revolutions per unit time of the tool body 1 becomes a predetermined value or more, the centrifugal force of the second piston 20 overcomes the biasing force of the spring 23, and the second piston 20 moves away from the axis O. Moving. The second piston 20 in the direction away from the axis O
When is moved, as described with reference to FIG. 3 (b), the second flow path 15 b eventually becomes the peripheral wall surface 20 of the second piston 20.
a and the fluid supply unit 12 and the first
The space 6a includes the main flow path 15, the first flow path 15a, and the second flow path 15a.
It is connected through the piston chamber 21. Then, since the fluid is supplied from the fluid supply unit 12 to the first space 6a, the pressure in the first space 6a rises, and the action of this pressure moves the piston 8 to the tip A side. And FIG.
As shown in, the hole drilling tool 2 is moved so as to project from the tool body 1 as the piston 8 moves toward the tip A side.

When the hole drilling tool 2 is moved to the rear end B, the rotation speed of the tool body 1 per unit time is set to be less than a predetermined value. The centrifugal force of the second piston 20 decreases due to the decrease in the number of rotations per unit time, and the second piston 20 in the second piston chamber 21 moves toward the axis O due to the urging force of the spring 23. To be done.
Then, as described with reference to FIG. 3A, the first flow path 15a is blocked by the peripheral wall surface 20a of the second piston 20, and the fluid supply unit 12 and the second space 6b are
The main flow path 15, the second flow path 15b, and the internal flow path 24 of the second piston 20 are connected to each other. Then, the second space 6
Since the fluid is supplied from the fluid supply unit 12 to b,
The pressure in the second space 6b rises, and the action of this pressure moves the piston 8 to the rear end B side. Then, as shown in FIG. 1, the hole drilling tool 2 is moved so as to be submerged in the tool body 1 as the piston 8 moves toward the rear end B side.

Here, the piston 8 moves from the front end A side to the rear end B.
When moving to the side, the fluid is filled in the first space 6a, but the fluid in the first space 6a at this time is the first space 6a.
And the outside of the tool body 1 are communicated with each other, and the piston 8 is not hindered from moving because it is discharged from the tool body 1 through a discharge port (not shown) provided with a filter. At this time, the diameter of the discharge port is set sufficiently smaller than the diameter of the piston 8 (piston chamber 6).

On the other hand, when the piston 8 moves from the rear end B side to the front end A side, the fluid filled in the second space 6b has a discharge port (not shown) communicating the front end face and the rear end face of the piston 8 with each other. (Illustration) and the inside of the hole drilling tool 2 are discharged from the tip of the hole drilling tool 2 via a flow path (not shown) formed along the axis O, so that the movement of the piston 8 is not hindered. At this time, the diameter of the discharge port is set sufficiently smaller than the diameter of the piston 8 (piston chamber 6).

As described above, the piston 8 movable in the direction of the axis O is provided in the piston chamber 6 formed inside the tool body 1, and is formed on the rear end B side of the piston 8 in the piston chamber 6. In each of the first space 6a formed and the second space 6b formed on the tip A side, the second space as a switching device is provided.
Since the fluids are independently supplied using the pistons 20, the hole drilling tool 2 connected to the pistons 8 by supplying the fluids to the first space 6a.
Can be moved to the tip end A side, and the hole drilling tool 2 can be moved to the rear end B side by supplying a fluid to the second space 6b. The second piston 20 performs a switching operation according to the number of revolutions of the tool body 1 per unit time. Therefore, for example, when the hole machining is performed, the tool body 1 is rotated at a high speed to tip the hole machining tool 2 at the tip. The hole drilling tool 2 can be moved to the A side, and can be moved to the rear end B side by rotating at low speed. Thus, the boring operation of the hole drilling tool 2 can be performed only by adjusting the number of rotations of the tool body 1 per unit time. Therefore, the boring operation of the hole drilling tool 2 attached to the tool body 1 can be quickly performed, and the cutting work can be efficiently performed.

Since the switching device is constituted by the second piston 20 which moves in the direction intersecting with the axis O according to the number of revolutions of the tool body 1 per unit time, the second piston 20 is a unit of the tool body 1. The fluid supply unit 12 and the first space 6a are simply moved according to the number of rotations per hour.
Either the first flow path 15a that connects the first space 6a and the second flow path 15b that connects the fluid supply unit 12 and the second space 6b is shut off, and the fluid for each of the first space 6a and the second space 6b is cut off. The supply of can be switched.

The second piston 20 moves so as to block the second flow passage 15b by centrifugal force when the rotation speed of the tool body 1 per unit time increases, and when the rotation speed decreases, the first flow passage 15a. Since it is set so as to move so as to shut off, the switching operation of the fluid supply to the first space 6a and the second space 6b can be easily performed with a simple configuration.

By providing the spring 23 for urging the second piston 20 toward the direction close to the axis O, when the rotational speed of the tool body 1 per unit time is low, the urging force of the spring 23 causes the second piston 20 to move. 2 pistons 2
0 is arranged at a position that blocks the first flow path 15a, and when the rotational speed is high, the centrifugal force of the second piston 20 causes the spring 2 to move.
The second piston 20 wins the urging force of No. 3 and the second flow path 1
It comes to be arranged in the position which intercepts 5b. In this way, the fluid can be switched to each of the first space 6a and the second space 6b with a simple configuration.

In the above embodiment, the second piston 2
The movement of 0 is based on the centrifugal force due to the rotation of the tool body 1, but if an actuator such as a piezoelectric element is connected to the second piston 20 and the number of rotations of the tool body 1 per unit time exceeds a predetermined value. , The second piston 20 is moved so as to drive the actuator to block the second flow path 15b, and when the rotation speed becomes less than a predetermined value, the actuator is driven to block the first flow path 15a. The two pistons 20 may be moved. In this case, the actuator
You may make it drive based on the detection result of the sensor attached to the tool main body 1 which can detect the rotation speed per unit time. On the other hand, as in the present embodiment, the biasing member 23
By urging the second piston 20 by means of the above and moving it by the centrifugal force based on the rotation of the tool body 1, it is possible to easily switch the flow paths without using an actuator with a simple structure. .

[0044]

According to the present invention, the movement of the hole drilling tool toward the front end side and the rear end side is performed by the first space which is the space on the rear end side of the piston and the second space which is the space on the front end side of the piston. Is performed by switching the supply operation of the fluid to each of the above, it is possible to quickly move the hole drilling tool connected to the piston. Since the switching device performs the fluid switching operation for each of the first space and the second space according to the rotation speed of the tool body, the hole drilling tool can be operated by simply changing the rotation speed of the tool body per unit time. You can move. Therefore, the retracting operation of the hole drilling tool attached to the tool body can be quickly and stably performed, and the cutting work can be efficiently performed.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a cutting tool of the present invention, showing a state in which a hole drilling tool is moving to a rear end side.

FIG. 2 is a cross-sectional view showing an embodiment of the cutting tool of the present invention, showing a state in which the hole drilling tool is moving toward the tip side.

FIG. 3 is an enlarged cross-sectional view of the vicinity of the switching device, (a) showing a state in which a fluid is being supplied to the second space,
(B) is a diagram showing a state in which a fluid is supplied to the first space.

FIG. 4 is a sectional view showing an example of a conventional cutting tool.

FIG. 5 is a diagram for explaining the operation of the conventional cutting tool.

[Explanation of symbols]

1 Tool body 2 hole processing tools 6 Piston chamber (room) 6a First space 6b Second space 8 pistons 12 Fluid supply section 15 main flow path 15a First flow path 15b Second flow path 20 2nd piston (switching device) 21 second piston chamber 23 Spring (biasing member) A tip B rear end CONT control device K movement mechanism O axis S cutting tool

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshiga Watanabe             1528, Nakashinden, Yokoi, Kobe-cho, Anpachi-gun, Gifu Prefecture             Address Mitsubishi Materials Corporation Gifu Factory             Within F-term (reference) 3C036 LL01                 3C050 EA00

Claims (4)

[Claims] 1. A tool main body that rotates around a predetermined axis, a hole drilling tool attached to the tool main body, and a tip of the hole drilling tool that is moved by moving the hole drilling tool in a direction along the axis. In a cutting tool provided with a moving mechanism for projecting and retracting from a tool body, the moving mechanism is provided movably in the axial direction in a chamber formed inside the tool body, and is connected to a rear end of the hole drilling tool. And a fluid supply capable of supplying fluid to each of a first space formed on the axially rear end side of the piston and a second space formed on the axially front end side of the piston in the chamber. And a switching device that switches a fluid supply operation by the fluid supply part to each of the first space and the second space, the switching device comprising: A cutting tool that performs switching operation according to the number of revolutions per unit time. 2. A main flow path connected to the fluid supply unit, a first flow path branched from the middle of the main flow path and connected to the first space, a main flow path branched from the middle of the main flow path, and the second flow path. A second flow passage connected to a space, wherein the switching device is arranged in a second piston chamber connected to the first flow passage and the second flow passage, depending on a rotation speed of the tool body per unit time. A second piston is provided so as to be movable in a direction intersecting with the axis, and one of the first flow path and the second flow path is blocked by the movement of the second piston. The cutting tool according to claim 1. 3. The second flow path is blocked when the rotation speed of the tool body per unit time exceeds a predetermined value, and the second flow path is blocked when the rotation speed of the tool body per unit time falls below a predetermined value. The cutting tool according to claim 2, wherein one flow path is blocked. 4. A urging member for urging the second piston in a direction of approaching the axis, the second body when the rotational speed of the tool body per unit time exceeds a predetermined value. When the piston moves in a direction away from the axis and the second flow path is blocked, and the rotation speed of the tool body per unit time becomes less than a predetermined value, the second piston is moved by the urging member. The cutting tool according to claim 3, wherein the first flow path is blocked by moving in a direction approaching the axis.