JP2000210803A - Cutting tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To elongate the service life of a slider by slidably mounting the slider having a cutting chip in a recess formed along a generating line of a circular cone, on an approximately conical tool body, and demountably mounting the cutting chip on an inclined mounting hole formed on a point of the slider. SOLUTION: This cutting tool properly used in working the valve hole of an engine is prepared by mounting a slider 7 having a cutting chip 5A on its point, slidably along a recess formed along a generating line of a circular cone of the tool body 1. The slider 7 has a chip mounting hole 7a on its point, and the mount hole 7a is inclined toward a tool outer peripheral side corresponding to a tool rear end side. A shank part 5b is fitted and inserted into this mounting hole 7 to demountably mount a shaft-shaped cutting chip 5A. Whereby a thickness between an inner periphery of the mounting hole 7a and a wall surface directing to a tool inner peripheral side, of the slider 7 can be ensured, and the durability of the slider 7 can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art As a cutting tool of this type, the inventors of the present invention have proposed the cutting tool shown in FIGS. 2 to 5 in, for example, Japanese Patent Application Laid-Open No. Hei 6-304804.
In these figures, the tool body 1 has a substantially conical shape, is mounted via an adapter 2 on a spindle end or the like of a machine tool (not shown), and is rotated around its axis O for cutting.
A bush 3 is mounted on the tip of the tool main body 1 along the axis O. A boring tool (not shown) such as a gun reamer is fitted into the bush 3 and the tool is The main body 1 can be moved forward and backward. Furthermore, three cutting edge tips 5A,
5B and 5C are provided.
Of the A, 5B, and 5C, two cutting edge tips 5B and 5C are directly fixed to the tool main body 1, while the remaining one cutting edge tip 5A extends along the generatrix direction of the cone formed by the tool main body 1. It is slidably mounted.

[0003] That is, the tool body 1 is provided along the direction of its conical generating line, that is, in the direction oblique to the axis O.
A groove 6 is formed as shown in FIGS.
A slider 7 is slidably mounted in the concave groove 6 along the concave groove 6, and the cutting edge tip 5A is detachably attached to the slider 7. A slider 7 is provided on the wall surfaces 6a and 6b of the concave groove 6.
, A spacer 8 and a wedge member 9 are detachably attached by clamp bolts 10, 11, respectively. Of these, the spacer 8 and the slider 7 can be engaged with each other by serration grooves (not shown). Have been.

Further, mounting holes 1a and 2a are formed along the axis O inside the tool body 1 and the adapter 2, respectively. The slide shafts 12 are formed in these holes 1a and 2a.
The coupling member 13 is inserted through the mounting hole 1a via a key 13a, and can rotate integrally with the tool body 1 around the axis O. By moving forward and backward, it is possible to move forward and backward in the direction of the axis O in the mounting hole 1a. Further, the concave groove 6 of the tool body 1 and the mounting hole 1a communicate with each other through a through hole 6d, while the slider 7 has a connecting pin 14 protruding into the mounting hole 1a through the through hole 6a. The slider 7 is connected to the coupling member 13 by the tip of the connection pin 14 being inserted into the oblique hole 13 b of the coupling member 13.
By moving the slider 3 forward and backward, the slider 7 slides in the concave groove 6 and slides the cutting edge tip 5A in a direction oblique to the axis O.

In order to machine the above-described valve hole with the cutting tool having such a configuration, a hole machining tool is mounted on the bush 3 and pulled into the base end side of the tool body 1 by the shaft 4. The tool body 1 is fed in the direction of the axis O while rotating about the axis O. First, the two cutting blade tips 5B, 5C fixed are chamfered C, C in the opening of the hole as shown in FIG. To form When the chamfers C and C are formed in this manner, the tool main body 1 is slightly retracted once while the tool main body 1 is being rotated, and then the slide shaft 12 is protruded so that the coupling member 13 is advanced. As described above, the slider 7 is slid via the connecting pin 14 to move the cutting edge tip 5A along the movement locus R to form the tapered surface P at the opening of the hole. Then, with the tool body 1 still rotating,
The hole drilling tool is advanced by the shaft 4 and inserted into the valve hole, and the valve hole itself is finished.

FIG. 4 shows the cutting blade tips 5A, 5A.
FIG. 4 shows the rotation trajectory around the axis O of B and 5C. As shown in FIG.
C is arranged such that the cutting blades 5b and 5c used for the cutting intersect each other at an obtuse angle in the rotation locus. On the other hand, the movement trajectory R that the cutting edge 5a of the cutting edge tip 5A moves by sliding the slider 7 is
B, 5C, between the cutting edges 5b, 5c,
b, 5c are arranged to extend in a direction intersecting at an obtuse angle. Further, reference numeral S in the figure denotes a hard member such as a sintered alloy fitted to the periphery of the opening such as a valve hole.

[0007]

Here, FIG. 5 shows a slider 7 in a conventional cutting tool having such a configuration.
As shown in FIG. 5, the cutting edge tip 5A attached to the slider 7 has an axial shape, and the cutting edge 5a is formed at the front end and the rear end is shown. The shank portion 5b is formed in the mounting hole 7a formed in the slider 7 from the inner peripheral side of the front end portion of the slider 7 toward the rear end side of the tool.
Is fixed by being inserted and pressed by the clamp screw 15. Reference numeral 16 in the drawing denotes an adjustment screw for adjusting the amount of protrusion of the cutting blade 5a in the direction of the axis O.

In this conventional cutting tool, the mounting hole 7a of the slider 7 is formed so as to be parallel to the axis O of the tool body 1, while the cutting edge chip 5 mounted in the mounting hole 7a is Since the opening of the valve hole is machined, the cutting edge 5a at the tip thereof must be disposed as close as possible to the axis O of the tool body 1, and as a result, the mounting hole in the slider 7 is formed. 7
As shown in FIG. 5, a must be formed along the side surface 7b near the side surface 7b of the slider 7 facing the tool inner peripheral side. However, when the mounting hole 7a is formed close to the side surface 7b in this manner, the gap between the side surface 7b and the inner peripheral portion of the mounting hole 7a is about 0.5 mm, and a sufficient thickness is secured. , And cracks and the like are easily formed in this portion. For example, the attachment and detachment of the clamp screw 15 at the time of replacing the cutting edge tip 5 due to the life of the cutting edge tip 5 due to wear of the cutting edge 5a and the like are repeated. Meanwhile, there was a possibility that the slider 7 might be damaged at an early stage.

The present invention has been made in view of such circumstances, and in a cutting tool having the above-described configuration, the position of a cutting edge of a cutting edge attached to a slider is made as close as possible to the axis of a tool main body. Another object of the present invention is to provide a cutting tool capable of securing a sufficient thickness between a side surface of the slider facing the tool inner peripheral side and a mounting hole and preventing damage to the slider.

[0010]

SUMMARY OF THE INVENTION In order to solve the above problems and achieve such an object, the present invention provides a substantially conical tool body rotated about an axis along a generatrix of the cone. And a slider provided with a cutting edge tip is slidably mounted along the groove in the groove, and is formed at the tip of the slider. The mounting hole is formed so as to be inclined toward the outer peripheral side of the tool toward the rear end side of the tool, and the shank portion on the rear end side of the cutting blade tip is inserted into the inclined mounting hole so that the cutting edge is formed. The chip is detachably attached to the slider. Therefore, in the cutting tool configured as described above, even if the position of the cutting edge at the tip of the cutting edge tip is arranged on the inner peripheral side of the tool, there is not enough space between the side surface of the slider and the inner periphery of the mounting hole at the rear end side of the tool. A large wall thickness can be ensured.

Here, it is desirable that the inclination angle formed by the inclined mounting hole of the slider with respect to the axis of the tool body is set to 45 ° or less. This is because this tilt angle is 4
If the angle is larger than 5 °, even a slight movement of the cutting edge tip in the mounting hole causes a large deviation in the radial direction with respect to the axis of the cutting edge, which may make it difficult to finely adjust the position of the cutting edge. Because. However, in the present invention, since the mounting hole is inclined toward the tool outer peripheral side toward the tool rear end side with respect to the axis of the tool main body as described above, the inclination angle is 0 °. As a result, the mounting hole does not become parallel to the axis, or the inclination angle is less than 0 ° and is inclined toward the tool inner peripheral side toward the tool rear end side.

[0012]

FIG. 1 shows an embodiment of the present invention. However, the cutting tool of the embodiment shown in FIG. 1 differs from the conventional cutting tool shown in FIGS. 2 to 5 only in the vicinity of the cutting edge tip 5A at the tip of the slider 7; 2 to 5 are denoted by the same reference numerals, and the description of other parts not shown is omitted.

That is, in the present embodiment, the mounting hole 7a formed at the front end of the slider 7 is open at the side surface 7b of the slider 7 facing the tool inner peripheral side. The shank portion 5b is inserted into the mounting hole 7a and the shaft-shaped cutting tip 5A mounted on the slider 7 is formed. The shank portion 5b is arranged so as to be inclined toward the outer peripheral side of the tool as it approaches the rear end side of the tool. Further, the inclination angle θ formed by the center line L of the mounting hole 7a with respect to the axis O of the tool body 1 is set to be 45 ° or less.

The mounting hole 7a in this embodiment has a circular cross section centered on the center line L, while the shank 5b has a cross section that can be inserted into the mounting hole 7a. A part of a large circle has a shape cut out by a flat surface, and the flat surface is directed toward the rake face (upper side with respect to the drawing in FIG. 1) of the cutting edge 5a of the cutting edge tip 5A, and the shank 5b , And is a pressing surface with which the clamp screw 15 abuts.
The slider 7 is provided with the center line L from the tool outer peripheral side.
An adjusting screw 16 is screwed in a direction perpendicular to the direction of the arrow. The tip of the adjusting screw 16 is formed in a convex conical shape and protrudes from a portion of the mounting hole 7a on the tool rear end side, while the shank portion 5b of the cutting blade tip 5A is formed. The rear end face is formed with an inclined surface which can be brought into contact with the tip end of the adjusting screw 16, and the contact position between the tip end and this inclined surface changes according to the screwing amount of the adjusting screw 16. The position of the cutting blade tip 5A in the direction of the center line L is adjusted so that the amount of protrusion of the cutting blade 5a in the direction of the axis O can be finely adjusted.

However, in the cutting tool configured as described above, the mounting hole 7a of the cutting edge tip 5 formed in the slider 7 is formed so as to be inclined toward the outer peripheral side of the tool toward the rear end of the tool. Therefore, even if the radial position of the cutting edge 5a with respect to the axis O is the same, the thickness between the inner periphery of the mounting hole 7a and the side surface 7b of the slider 7 facing the inner periphery of the tool is reduced after the tool. The thickness can be increased toward the end, and for example, a thickness of 1 mm or more can be secured at the tip of the slider 7. Therefore, according to the cutting tool having the above-described configuration, it is possible to secure the rigidity in the portion between the sliders 7 and improve the strength thereof, and to perform clamping by exchanging the cutting blade tip 5 due to wear of the cutting blade 5a or the like. Even if the screw 15 is frequently attached and detached, cracks can be prevented from being generated in this portion,
The life of the slider 7, that is, the tool life can be extended.

When the mounting hole 7a of the slider 7 to which the cutting blade tip 5 is mounted is formed so as to be inclined toward the outer peripheral side of the tool toward the rear end of the tool, the inclination of the mounting hole 7a is large. The greater the thickness between the mounting hole 7a on the rear end side of the tool and the side surface 7a of the slider 7, the greater the thickness can be secured. 1
6, when adjusting the amount of protrusion of the cutting blade 5a,
Since the radial position of the cutting edge 5a with respect to the axis O also greatly changes, accurate fine adjustment of the position of the cutting edge 5a may be difficult. Therefore, this inclined mounting hole 7a
Of the center line L of the tool body 1 with respect to the axis O of the tool body 1
Is desirably set so as to exceed 0 ° and be 45 ° or less as in the present embodiment.

[0017]

As described above, according to the present invention,
Without changing the position of the cutting edge, it is possible to secure the thickness of the part between the inner circumference of the mounting hole where the cutting edge tip is mounted and the wall facing the tool inner side of the slider, and replace the cutting edge tip. Can prevent cracks from forming in this area even if cutting is performed frequently, prolonging the life of the slider, and thus prolonging the tool life, facilitating smooth and stable cutting. Becomes

[Brief description of the drawings]

FIG. 1 is an enlarged view of the vicinity of a distal end of a slider 7 according to an embodiment of the present invention.

FIG. 2 is a side view showing a conventional cutting tool.

FIG. 3 is a front view of the conventional cutting tool shown in FIG. 2 as viewed from a tool tip side.

FIG. 4 is a rotation locus of the cutting edge tips 5A, 5B, 5C around the axis O in the conventional cutting tool shown in FIG.

FIG. 5 is an enlarged view of the vicinity of the tip of a slider 7 of the conventional cutting tool shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tool main body 5A, 5B, 5C Cutting edge tip 5a Cutting edge of cutting edge tip 5A Shank part of cutting edge tip 5A 6 Recessed groove 7 Slider 7a Mounting hole 7b Side surface of slider 7 facing the tool inner peripheral side 15 Clamp screw 16 Adjustment screw O Rotation axis of the tool body 1 T Tool rotation direction R Movement locus of the cutting edge 5a

Claims (2)

[Claims] 1. A substantially conical tool body rotated about an axis is formed with a concave groove along a generating line of the cone, and a slider provided with a cutting edge tip in the concave groove extends along the concave groove. A cutting tool that is slidably mounted at the tip of the slider, wherein a mounting hole that is inclined toward the outer periphery of the tool toward the rear end of the tool is formed at the tip of the slider, and the cutting edge tip A cutting tool, characterized in that a shank on the rear end side is inserted into the mounting hole and is detachably attached to the slider. 2. The apparatus according to claim 1, wherein an inclination angle of the mounting hole with respect to the axis is set to 45 ° or less.
The cutting tool according to 1.