JP2006007396A - Cutting tool and tool body used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tool body that reliably suppresses chatter vibration generated in a tool body.
A rear end portion of a tool body 10 rotated around an axis O serves as a mounting portion 11 for a machine tool, and is drilled from a front end surface 10A of the tool body 10 toward a rear end side in the axis O direction. In the cutting tool in which the reamer 20 is mounted in the mounting hole 12, the section between the mounting hole 12 and the mounting portion 11 inside the tool body 10 is perpendicular to the axis O and is closer to the rear end side than the mounting hole 12. The cavity 13 having a larger cross-sectional area is formed. A cutting blade 31 that is inclined with respect to the axis O is provided on the outer periphery of the tip of the tool body 10. The hollow portion 13 forms part of the cutting fluid supply passage.
[Selection] Figure 1

Description

  The present invention provides a cutting tool for machining a pilot hole formed in a workpiece, for example, machining a valve hole in a cylinder head of an engine into a predetermined inner diameter and processing an opening of the valve hole into a predetermined shape. It relates to a cutting tool.

Conventionally, as this type of cutting tool, for example, one disclosed in Patent Document 1 is known, and an example thereof is shown in FIG.
In the cutting tool shown in FIG. 2, a rear end side portion of the tool main body 1 rotated around the axis O serves as a mounting portion 2 to the machine tool, and a rear end side in the axis O direction from the front end surface 1A of the tool main body 1. A long, substantially cylindrical reamer (hole machining tool) 4 is mounted coaxially with the axis O in the mounting hole 3 drilled toward the end, and further, on the outer periphery of the tip of the tool body 1, The cutting blade 5 which inclines with respect is provided.

The rear end portion of the mounting hole 3 is an adjustment bolt receiving hole 6 into which an adjusting bolt 6A for adjusting the position of the cutting blade of the reamer 4 is screwed. The rear end of the adjusting bolt receiving hole 6 On the side, a supply hole 7 having an inner diameter substantially the same as the inner diameter of the adjustment bolt housing hole 6 and forming a part of the supply passage of the cutting fluid is formed.
Further, a pipe 9 fixed directly to the tool body 1 with a ring member 8 is provided on the rear end side of the supply hole 7 so as to protrude into the internal space of the mounting portion 2. Cutting fluid is supplied to the supply hole 7 from the machine side.

Then, when the tool body 1 is rotated around the axis O and sent toward the tip end in the direction of the axis O, the reamer 4 mounted in the mounting hole 3 of the tool body 1 is, for example, a valve in the cylinder head of the engine. A valve seat in which a hole (a pilot hole formed in a workpiece) is machined to a predetermined inner diameter, and a cutting blade 5 provided on the outer periphery of the tip end of the tool body 1 is in contact with the valve head opening. The surface is processed.
JP 2002-59313 A

By the way, in such a cutting tool, the tool main body 1 is inevitably unbalanced, and the weight of the tool main body 1 is very large. When the tool is rotated around the axis O at a high speed, chatter vibration is generated in the tool body 1 and the machining accuracy is lowered.
In the cutting tool shown in FIG. 2, a guide pad 5 </ b> A that can be slidably contacted with the processing surface processed by the cutting blade 5 is provided so as to be positioned on the substantially opposite side of the cutting edge 5 with the axis O interposed therebetween. Therefore, the tool body 1 may be guided by the guide pad 5A to suppress the chatter vibration. In this case, fine adjustment such as how far the guide pad 5A is retracted with respect to the cutting blade 5 is performed. Since work is required, it cannot be an effective solution for suppressing the chatter vibration.
This invention is made | formed in view of the said subject, and it aims at providing the cutting tool which can suppress the chatter vibration which arises in a tool main body effectively, and the tool main body used for this.

  In order to solve the above-described problems and achieve such an object, a cutting tool according to the present invention has a rear end side portion of a tool body rotated about an axis as an attachment portion to a machine tool. A cutting tool in which a drilling tool is mounted in a mounting hole drilled from the front end surface of the main body toward the rear end side in the axial direction, and the mounting hole and the mounting portion inside the tool main body A cavity portion having a cross-sectional area larger than that of the rear end side portion of the mounting hole in a cross section perpendicular to the axis is formed between the tool main body according to the present invention. A tool main body used in the cutting tool of the above, wherein a cross-sectional area between the mounting hole and the mounting portion inside the tool main body is larger than a rear end side portion of the mounting hole in a cross section perpendicular to the axis. That a cavity having It is an butterfly.

According to the present invention, since the weight of the tool main body can be reduced by the amount of the hollow portion formed in the tool main body, the tool main body in which the unbalanced state originally occurred is rotated at a high speed. Even if it is a case, the centrifugal force which acts on a tool main body can be made small, and the chatter vibration which arises in a tool main body as a result can be suppressed effectively. Further, by forming such a hollow portion, the center of gravity of the tool body can be moved to the rear end side, and the chatter vibration can be made more difficult to occur.
Furthermore, since the cavity is formed inside the tool body, the rigidity of the tool body may be inadvertently reduced as compared with the case where the outside of the tool body is cut out to reduce its weight. There is nothing.

  Further, a cutting blade that is inclined with respect to the axis is provided on the outer periphery of the tip of the tool body, and the cutting tool according to the present invention, for example, forms a valve hole in a cylinder head of an engine with a predetermined inner diameter by the drilling tool. In the case where the opening of the valve hole is processed into a predetermined shape (valve seat surface with which the valve head abuts) by the cutting blade, a conventional guide pad is not used. However, chatter vibration generated in the tool body can be effectively suppressed.

  Further, in the present invention, it is preferable that the hollow portion constitutes a part of the cutting fluid supply passage, and such a configuration causes a problem of interference between the hollow portion and the cutting fluid supply passage. Therefore, the volume of the cavity can be increased as much as possible within a range that does not impair the rigidity of the tool body, and the weight of the tool body can be further reduced.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
As shown in FIG. 1, the tool body 10 of the cutting tool according to the present embodiment has a substantially multi-stage columnar shape centering on an axis O rotated around the axis O, and the rear end portion is a machine tool. It is made the attachment part 11 to.
The tool body 10 has the mounting portion 11 inserted into the machine tool, and the mounting reference surface 11A that stands up from the tip end of the mounting portion 11 to the outer periphery in the radial direction is opposed to the end surface of the machine tool so as to come into contact therewith. And is attached to the machine tool.

An axis O extending toward the rear end side in the axis O direction is provided on the tip surface 10A located at the tip of the tool body 10 and extending so as to face the tip side in the axis O direction and substantially orthogonal to the axis O. A mounting hole 12 is formed around the center.
The rear end portion of the mounting hole 12 is an adjustment bolt housing hole 12A having an inner diameter that is one step larger than that of the front end portion of the mounting hole 12 and an internal thread portion formed on the inner peripheral surface.

On the other hand, the reamer 20 as a hole machining tool to be mounted in the mounting hole 12 has a long, substantially cylindrical shape centered on the axis O rotated around the axis O in a state of being mounted in the mounting hole 12. The front end side portion is a blade portion 21 and the rear end side portion is a shank portion 22.
Although not shown, a single chip discharge groove extending along the axis O is formed on the outer periphery of the blade portion 21, and the wall surface of the chip discharge groove facing the front side in the rotation direction T of the tool body 10. A cutting blade is provided on the outer periphery of the tip.

In the reamer 20 configured as described above, the shank portion 22 has a rear end side portion of the shank portion 22 that is a part of the adjustment bolt receiving hole 12A with respect to the mounting hole 12 formed in the front end surface 10A of the tool body 10. It is inserted so as to protrude into the inside.
The rear end surface 22A of the shank portion 22 of the reamer 20 is brought into contact with the tip of the adjustment bolt 23 screwed into the adjustment bolt housing hole 12A. By adjusting the screwing position of the adjustment bolt 23, the reamer 20 The position of the cutting blade provided on the 20 blade portions 21 can be adjusted.

In the reamer 20 in which the shank portion 22 is inserted into the mounting hole 12, the flat surface 22 </ b> B formed by cutting out the outer peripheral surface of the shank portion 22 is pressed from the radial direction by the clamp screw 24. Thereby, the reamer 20 is coaxial with the axis O with respect to the mounting hole 13 so that the blade 21 protrudes along the axis O from the tip surface 10A of the tool body 10 toward the tip in the axis O direction. It is fixed and attached.
Further, the outer peripheral surface of the shank portion 22 of the reamer 20 is pressed from the radial direction by a plurality of adjustment screws 25 provided, for example, at substantially equal intervals in the circumferential direction at the distal end portion of the tool body 10. By adjusting the screwing position, it is possible to adjust the deflection accuracy of the cutting blade provided in the blade portion 21 of the reamer 20.

In the present embodiment, inside the tool body 10, between the mounting hole 12 and the mounting portion 11, specifically, the rear end of the mounting hole 12 (the rear end of the adjustment bolt accommodating hole 12) and the mounting portion 11. A cavity portion 13 is formed between the mounting reference surface 11A located at the tip of the head and a position separated from the attachment reference surface 11A toward the tip in the direction of the axis O by a predetermined distance.
The hollow portion 13 has a substantially cylindrical hole shape with the axis O as the center, and the cross-sectional area in a cross section orthogonal to the axis O is a breakage of the adjustment bolt accommodating hole 12A that is the rear end side portion of the mounting hole 12. It is set to be larger than the area. That is, the cavity 13 having an inner diameter (for example, twice or more inner diameter) larger than the inner diameter of the adjusting bolt accommodating hole 12A is formed on the rear end side of the adjusting bolt accommodating hole 12A.

In addition, a pipe 14 is provided on the rear end side of the cavity portion 13 so as to protrude toward the rear end side in the direction of the axis O toward the inner space of the mounting portion 11. The cutting fluid is supplied to the portion 13.
The cutting fluid once stored in the cavity 13 is supplied to a cutting site by a cutting edge provided in the blade portion 21 of the reamer 20 and a cutting site by a cutting blade 31 described later. That is, the cavity 13 forms part of the cutting fluid supply passage.

Here, the pipe 14 for supplying the cutting fluid to the cavity portion 13 is not directly fixed to the tool body 10 because the cavity portion 13 is formed larger than the conventional one. 15 is fixed to the tool main body 10 via 15.
The block 15 has a substantially columnar shape, and in a fixed state to the tool body 10, an internal thread portion 15 </ b> A centering on an axis O opening at the front end surface of the block 15, and a rear end side of the internal thread portion 15 </ b> A. It has an insertion part 15B centering on an axis O that is continuous and opens at the rear end face of the block 15. Further, since the inner diameter of the female screw portion 15A is one step larger than the inner diameter of the insertion hole 15B, a step portion 15C is formed at the connection portion between the female screw portion 15A and the insertion portion 15B.

The pipe 14 is inserted into the insertion portion 15 </ b> B of the block 15 such that the flange portion 14 </ b> A formed at the tip end in the axis O direction is caught by the step portion 15 </ b> C of the block 15.
In this state, the ring member 16 having a female thread portion formed on the outer peripheral surface is screwed into the female thread portion 15A of the block 15 and the flange portion 14A of the pipe 14 is pressed by the ring member 16 so that the pipe 14 is against the block 15. Fixed.

The block 15 to which the pipe 14 is fixed is inserted into a block accommodation hole 17 which is located on the rear end side of the cavity portion 13 and is formed in a substantially cylindrical hole shape corresponding to the block 15.
Next, the block 15 has a notch 15D formed by notching the outer peripheral surface thereof, and is pressed by the fixing screw 18 from an oblique direction toward the distal end side in the axis O direction as it goes toward the radially inner periphery side. , And is fixed in the block accommodation hole 17.

  In this way, the pipe 14 protruding into the inner space of the mounting portion 11 toward the rear end side in the axis O direction is provided on the rear end side of the cavity portion 13, and the cutting oil from the machine tool side is supplied from the pipe 14. , The hexagonal holes 16A used when screwing the ring member 16 are sequentially passed through and supplied to the cavity 13.

  A plurality of (for example, three) cartridges 32 that hold the throw-away tip 30 formed with the cutting blade 31 are attached to the outer periphery of the tip of the tool body 10 in the circumferential direction. As a result, a plurality of cutting edges 31 are provided in the circumferential direction on the outer periphery of the tip of the tool body 10 so as to be inclined toward the outer peripheral side in the radial direction as it goes toward the rear end side in the axis O direction.

Here, in the present embodiment, each of the plurality of cartridges 32 is pressed by the adjusting screw 33 from an oblique direction toward the radially inner periphery side toward the distal end side in the axis O direction, By adjusting the screwing position of the adjusting bolt 33, the position of the cutting edge 31 of the throw-away tip 30 held by the cartridge 32 can be adjusted.
As described above, when the adjustment bolt 33 is screwed in the oblique direction with respect to the tool body 11, the adjustment bolt 33 can be directly screwed from the outer peripheral side of the tool body 10 with a tightening tool such as a hexagon wrench. Compared with the case where the adjustment bolt 33 is screwed along the direction of the axis O, it is not necessary to form a large space in the tool body 10 for inserting a tightening tool such as a hexagon wrench. The rigidity of 10 is not reduced.

  The cutting tool configured as described above is rotated around the axis O while being sent toward the tip end side in the direction of the axis O, so that the reamer 20 causes a valve hole (formed in a workpiece, for example, in a cylinder head of an engine) A plurality of cutting blades 31 provided on the outer periphery of the tip end portion of the tool body 10 to form a valve seat surface with which the valve head abuts against the opening portion of the valve hole. It is designed to be processed into a shape.

  According to the present embodiment as described above, since the tool body 10 can be reduced in weight by the amount of the cavity 13 formed inside the tool body 10, an unbalanced state is originally generated. Even when the tool body 10 is rotated at a high speed, the centrifugal force acting on the tool body 10 can be reduced, and chatter vibration generated in the tool body 10 as a result can be effectively suppressed.

Moreover, by forming such a hollow portion 13 in the tool body 10, the center of gravity of the tool body 10 can be moved to the rear end side in the axis O direction, and the chatter vibration can be made less likely to occur.
Furthermore, since the cavity 13 is formed inside the tool body 10, the rigidity of the tool body 10 is inadvertently reduced as compared with a case where the outside of the tool body 10 is cut out to reduce its weight. There is no such thing.

  In addition, in this embodiment, since the cavity 13 forms a part of the cutting fluid supply passage, the tool body does not cause a problem of interference between the cavity 13 and the cutting fluid supply passage. The volume of the cavity 13 can be increased as much as possible within a range that does not impair the rigidity of the tool 10, and the tool body 10 can be further reduced in weight.

Therefore, like the cutting tool of this embodiment, the valve hole in the cylinder head of the engine is machined to a predetermined inner diameter, and the valve seat surface where the valve head abuts on the opening of the valve hole is machined. In some cases, chatter vibration of the tool body 10 can be effectively suppressed without using a guide pad that requires complicated adjustment work.
In order to further reduce the weight of the tool body 10, the tool body 10 may be made of a light metal such as titanium or aluminum, instead of being made of generally used steel.

  In the present embodiment, the reamer 20 is selected as the drilling tool to be mounted in the mounting hole 12 of the tool body 10. However, the present invention is not limited to this, and other drilling tools can be used as the mounting hole of the tool body 10. 12, and it is not always necessary to provide the cutting edge 31 on the outer periphery of the tip of the tool body 10.

It is a section side view showing the cutting tool of the embodiment of the present invention. It is a cross-sectional side view which shows the conventional cutting tool.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Tool main body 10A Tip surface 11 Mounting part 12 Mounting hole 13 Cavity part 14 Pipe 15 Block 16 Ring member 20 Reamer (drilling tool)
21 Blade 30 Throw away tip 31 Cutting blade 32 Cartridge O Axis T Rotation direction

Claims (4)

A rear end portion of the tool body rotated around the axis is a mounting portion to a machine tool, and a drilling tool is provided in a mounting hole drilled from the front end surface of the tool body toward the rear end side in the axial direction. Is a cutting tool to be mounted,
Between the mounting hole and the mounting portion in the tool body, a hollow portion having a cross-sectional area larger than that of a rear end side portion of the mounting hole in a cross section perpendicular to the axis is formed. A cutting tool. The cutting tool according to claim 1,
A cutting tool characterized in that a cutting blade inclined with respect to the axis is provided on the outer periphery of the tip of the tool body. The cutting tool according to claim 1 or 2,
A cutting tool, wherein the hollow portion forms part of a cutting fluid supply passage. A tool body used for the cutting tool according to any one of claims 1 to 3,
Between the mounting hole and the mounting portion in the tool body, a hollow portion having a cross-sectional area larger than that of a rear end side portion of the mounting hole in a cross section perpendicular to the axis is formed. The tool body.

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