JP3215040B2 - Rotary bite - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary tool in which a disc-shaped throw-away tip (hereinafter referred to as a tip) is rotatably mounted on the tip of a tool body.

[0002]

2. Description of the Related Art As a rotary tool of this type, the inventors of the present invention have proposed a rotary tool as shown in FIGS. 3 and 4 in Japanese Patent Application Laid-Open No. 7-112305. This rotary tool is used for outer diameter cutting of a work material. As shown in FIG. 3, a disc-shaped tip 2 is turned around the center axis O of the tip of a square shaft-shaped tool body 1 as shown in FIG. The tip 2 has a circular surface 3 which is movably attached to the chip 2 and is arranged upward.
A cutting edge 5 is formed at the intersection ridge line between the tip and the peripheral surface 4 of the chip 2. Note that this chip 2 has both circular surfaces 3,
The cutting edges 5 and 5 are formed at the intersection ridges of the peripheral surface 4 and the cutting surface 3, so that the cutting edge 5 can be used twice with one tip 2.

As shown in FIG. 4, a center axis 6, 6 is formed at the center of the two circular surfaces 3, 3 on the tip 2, while a tip end of a cutting tool body 1 for holding the tip 2 therebetween. The center shaft 6,
Shaft holes 9, 9 into which the insert 6 is inserted are formed, so that the chip 2 is rotatable around its axis O. Further, the clamp piece 7 presses the chip 2 toward the sheet 8 by a brake washer 11, a wave washer 12, a coil spring 13 and the like loosely inserted around a clamp screw 10 of an attachment portion to the tip of the cutting tool body 1. The pressing force to be adjusted can be adjusted to be a predetermined pressing force,
Thus, the driven rotation speed of the chip 2 can be adjusted as appropriate.

[0004]

However, in such a conventional rotary tool, as described above, the chip 2 has the center shafts 6 and 6 formed on the two circular surfaces 3 and 3 thereof, and the clamp piece 7 and the sheet 8. In order to perform high-precision cutting, the rotational trajectory of the cutting edge 5 is made to be an accurate circle with respect to the center axis O of the tip 2 by being inserted into the shaft holes 9, 9 of the cutting tool 5. The degree of concentricity between the cutting edge 5 and the two center axes 6 and 6 and the center axis 6 and 6
And the concentricity between the shaft holes 9 and 9 into which they are inserted, and the concentricity between the central shafts 6 and 6 and between the shaft holes 9 and 9 must also be adjusted with high accuracy. However, when the number of elements requiring accuracy is increased in this way, it is difficult to obtain the high machining accuracy as described above due to accumulation of errors included in each element, and conversely, when trying to obtain such high accuracy, Each component must be machined with very high precision, and its assembly also requires considerable skill.

In particular, in the rotary tool, since the tip 2 is positioned by inserting the center shafts 6, 6 into the shaft holes 9, 9, the outer diameter dimensional accuracy of the cutting blade 5 with respect to the center shafts 6, 6 is improved. That is, if the dimensional accuracy of the peripheral surface 4 is insufficient, the tip 2 rotates eccentrically with respect to the center axis O, and the surface roughness of the machined surface of the workpiece W is remarkably deteriorated. For this reason, it is necessary to manufacture the chip 2 with a particularly high precision. In order to meet such a demand, for example, the range of the outer diameter tolerance of the chip 2 is set to two.
If an attempt is made to improve the outer diameter dimensional accuracy by setting the diameter to 4 μm to 10 μm, the manufacturing cost will increase by about 30%, which is extremely uneconomical.

The present invention has been made under such a background, and the cutting edge is accurately arranged with respect to the center axis of rotation without particularly requiring a high outer diameter dimensional accuracy for the chip. It is an object of the present invention to provide a rotary tool capable of positioning a chip in such a manner as to achieve high processing accuracy.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems and to achieve such an object, the present invention provides a cutting tool comprising a sheet having a columnar shaft at the tip of a cutting tool body. A chip mounting member having a chip mounting seat having a bottom plate portion and a peripheral wall portion and having a disk-shaped chip inserted therein is formed on the upper portion of the seat. removable as upward freely mounted, the
The upper part of the sheet and the above chip facing the upper part of the sheet
Non-clamping of the above chip between the lower surface of the bottom plate of the mounting member
In the pump state, from the outer peripheral side to the center axis side
Accordingly, by forming a gap in which the interval becomes large , and pressing the tip inserted into the tip mounting seat by the clamp means, the tip mounting member is elastically deformed so as to reduce the gap , and the peripheral wall portion is used. The tip is tightened to position the tip. Therefore, according to the rotary cutting tool having such a configuration, if the inner peripheral surface of the peripheral wall portion of the chip mounting member constituting the chip mounting seat is accurately formed with respect to the center axis of rotation, the center of the chip is Even if the outer diameter dimensional accuracy of the cutting blade is somewhat coarse, when the peripheral wall portion of the tip mounting member is elastically deformed, the tip is tightened and positioned so that the center of the tip coincides with the center axis of rotation. The blade can be accurately rotated about the central axis.

[0008] Then, to the peripheral wall portion upon pressing the bottom surface of the chip mounting seat by clamping means chip as described above is configured to clamp the chip faces the upper portion of the seat, on top of the sheet A gap is formed between the outer surface of the chip mounting member and the lower surface of the bottom plate portion of the chip mounting member, where the distance increases from the outer peripheral side toward the center axis side, and the chip is pressed against the bottom surface of the chip mounting seat by the clamping means. By doing so, the tip mounting member is elastically deformed so that this gap is reduced ,
By the deformation of the chip mounting member in this way, the bottom plate between the bottom of the chip mounting member and the bottom surface of the chip mounting seat is
From the unclamped state, the outer peripheral side is displaced relatively to the inner peripheral side in a direction opposite to the pressing direction. Accordingly, the diameter of the peripheral wall of the chip mounting seat is reduced so as to be narrowed, and the outer peripheral surface of the chip is And the positioning is performed. What
Contact with the bottom of the chip mounting seat
Non-clamped state between the chip and the seating surface facing the surface
At the distance from the center axis side to the outer circumference side
May be formed.

Further, in order to prevent the sheet and the chip mounting member from falling off, the above-mentioned sheet is mounted by inserting the above-mentioned shaft into the sheet mounting hole provided in the tool body, and the lower end of the above-mentioned shaft is mounted. A seat restraining member for restraining movement of the shaft portion in the center axis direction in the seat mounting hole, or preventing the chip mounting member from falling off the sheet by engaging the chip mounting member on the sheet. It is desirable to provide members.

[0010]

1 and 2 show an embodiment of the present invention. FIG. 1 shows an unclamped state where a chip is not mounted, and FIG. 2 shows a state where a chip is mounted. It shows a clamped state. In the present embodiment, a mounting hole 23 is formed in the tip end portion 22 of the cutting tool main body 21 so as to penetrate obliquely from the upper surface to the lower surface, and the mounting hole 23 has a substantially cylindrical bearing member 24. Is inserted, and the inner periphery of the bearing member 24 is a seat mounting hole 25. A substantially columnar sheet 26 having an upper end 26A whose diameter is increased by one step is inserted into the seat mounting hole 25, and the columnar shaft 26B is inserted into the sheet mounting hole 25 to be rotatable around the central axis O of the shaft 26B. A chip mounting member 27 having a substantially bottomed annular shape is detachably attached to the upper end portion 26A of the sheet 26 with its annular portion facing upward. A substantially disk-shaped chip 29 is further detachably mounted as the seat 28.

Here, the upper end 24 of the bearing member 24
A is a cylindrical body 24B fitted into the mounting hole 23.
The seat 26 has a lower surface of an upper end portion 26A of the bearing member 24.
The upper end 24A is slidably attached to the upper surface of the upper end 24A. A conical concave portion 24C is formed in the body portion 24B of the bearing member 24, while the cutting tool body 2
1, a mounting screw 30 having a conical head 30A is screwed in, and the head 30A is in contact with the lower side of the concave portion 24C, whereby the bearing member 24 is inserted into the mounting hole 23. It is designed to be retracted and detented.

Further, at the lower end of the shaft portion 26B of the seat 26 inserted into the seat mounting hole 25, a seat mounting hole 2 is provided.
A disk-shaped sheet restraining member 31 having a diameter larger than 5 is screwed and mounted by mounting bolts 32, 32 after the sheet 26 is inserted into the sheet mounting hole 25, whereby the sheet 26 is While rotation about the central axis O is allowed, movement in the direction of the axis O is restricted. On the other hand, in the present embodiment, the upper end 26A of the sheet 26 has an upper surface 26C formed in a direction orthogonal to the axis O, and a central portion of the upper surface 26C has a circular fitting centered on the axis O. A hole 26D is formed so as to be depressed one step from the upper surface 26C, and a screw hole 26E is formed along the axis O at the center of the bottom surface of the fitting hole 26D.

In the present embodiment, the tip attachment member 27 attached to the upper end 26A of the sheet 26 is made of a material that is relatively elastically deformable, such as spring steel, and has a substantially circular shape centered on the axis C. Plate-shaped bottom plate 27A
And a peripheral wall portion 27B formed so as to circumscribe the peripheral edge thereof in an annular shape around the axis C, and has the above-described bottomed annular shape. Also, this bottom plate portion 27A
A circular insertion hole 27C penetrates the center portion of the bottom plate 27A along the axis C, and a lower surface 27D of the bottom plate portion 27A is fitted around the periphery of the insertion hole 27C in an annular shape centering on the axis C. The fitting portion 27E is formed so as to protrude downward.
It is set to a size that can be fitted to D.

The lower surface 27D of the bottom plate 27A
1 is formed in a conical surface centered on the axis C in which a portion on the outer peripheral side from the fitting portion 27E is inclined downward at an extremely small angle toward the outer peripheral side. As shown in FIG.
D, when the chip mounting member 27 is mounted on the upper end portion 26A of the seat 26, the lower surface 2 of the sheet mounting member 27 is
Between the 7D and the upper surface 26C of the seat 26, so that the central axis O from the outer peripheral side thereof, a gap S ₁ progressively spacing increases toward the C side is formed. On the other hand, the chip mounting seat 28 forms a disc-shaped recess by using the upper surface of the bottom plate 27A of the chip mounting member 27 thus configured as the bottom surface 28A and the inner peripheral surface of the peripheral wall 27B as the wall surface 28B. Is formed. Further, in the present embodiment, the bottom surface 28A of the tip mounting seat 28 is also formed in a conical surface centered on the axis C which is inclined downward toward the outer peripheral side similarly to the lower surface 27D. The inclination angle is set equal to the inclination angle of the lower surface 27D. Therefore, the bottom plate portion 27A is not formed in a strictly disc shape but in a conical plate shape with the axis C as a center.

The wall surface 28B of the tip mounting seat 28
Is formed in a cylindrical shape around the axis C,
The outer peripheral surface of the peripheral wall portion 27B is formed in a tapered surface shape whose diameter decreases as it goes upward. Further, a countersunk screw 33 is inserted into the bottom plate portion 27A of the chip mounting member 27 from the bottom surface 27A side and screwed to the upper end portion 26A of the sheet 26 as a member for preventing the chip mounting member 27 from falling off.
Here, the tip mounting member 2 into which the flathead screw 33 is inserted
7, the bottom surface 28A side is formed in a tapered surface shape that engages with the head of the flat head screw 33 and is formed deeper than the thickness of the head, while the lower surface 27D side is formed with the flat head screw 33. The head of the flat head screw 33 is formed from the bottom surface 28A of the tip mounting seat 28 so as not to interfere with the elastic deformation of the tip mounting member 27 described later. It does not protrude.

In the present embodiment, the chip 29 mounted on the chip mounting seat 28 is formed of a hard material such as a cemented carbide and has a substantially disk shape, and the circular upper surface is a rake face 29A. At the same time, the peripheral surface is a flank 29B, and at the intersection ridge line between the rake surface 29A and the flank 29B,
A circular cutting blade 34 is formed. Here, the outer diameter of the peripheral surface serving as the flank 29B is set slightly smaller than the inner diameter of the wall surface 28B so that the tip 29 can be fitted into the chip mounting seat 28. Further, a lower surface of the chip 29 opposite to the rake surface 29 is a seating surface 29C which sits on a bottom surface 28A of the chip mounting seat 28, and the seating surface 29C is a central axis of a disk formed by the chip 29. It is formed in a direction orthogonal to X. Accordingly, since the bottom surface 28A is formed in a conical shape as described above, the tip 29 is aligned with the center axis C of the tip mounting member 27 so that the tip X is aligned with the center axis C of the tip mounting member 27.
In the unclamped state, between the seating surface 29C and the bottom surface 28A, the center axis C of the chip mounting member 28, that is, the center axis O of the seat 26 as shown in FIG. so that the central axis line X, C, clearance S ₂ to gradually distance toward the outer peripheral side from the O side is increased is formed.

The center of the tip 29 is provided with a clamp screw 35 as a clamping means in the present embodiment.
Is penetrated along the axis X. Here, the clamp screw 35 has a countersunk head like the drop-off prevention member of the tip mounting member 27, and the portion of the insertion hole 29D on the rake face 29A side is corresponding to the seating face 29C side. It is formed in the shape of a tapered surface whose diameter decreases as going toward. On the other hand, this insertion hole 2
The portion on the side of the seating surface 29C of 9D is formed so as to gradually increase in diameter toward the seating surface 29C, and a slight gap is formed between the portion and the clamp screw 35. Fine movement in the radial direction of 29 is allowed. Further, on the outer peripheral side of the rake face 29A of the chip 29, a seating surface 29 is formed toward the inner peripheral side.
Chip breaker 29 that inclines to the C side and then cuts upward
E is formed so as to orbit along the cutting edge 34, thereby improving the sharpness of the cutting edge 34. further,
At the upper edge of the flank 29B, an inclined surface 29F that is inclined inward toward the inner side as it goes upward is formed so as to also go along the cutting edge 34, so that the strength of the cutting edge 34 is maintained. Have been. Therefore, the cutting edge 34 is strictly formed at the intersection ridge between the chip breaker 29E and the inclined surface 29F.

However, in the rotary tool thus constructed, the upper surface 26C of the sheet 26 as described above is in a non-clamped state in which the chip 29 is merely inserted into the chip mounting seat 28 of the chip mounting member 27. The clearance S is provided between the tip mounting member 27 and the lower surface 27D.
₁ is the seating surface 29C of the chip 29 and the chip mounting seat 2
Between the 8 bottom 28A the gap S ₂ is in a state of being formed. Then, from this unclamped state, the chip 29 and the chip mounting member 27 are pressed by the head of the clamp screw 35 by inserting the clamp screw 35 into the insertion hole 29D and the insertion hole and screwing it into the screw hole 26E of the sheet 26. Accordingly, the tip mounting member 27
Is elastically deformed so that the bottom plate 27A sinks into the upper surface 26C of the sheet 26, that is, the gaps S ₁ and S ₂ are reduced. Then, due to this elastic deformation, the peripheral wall portion 27B of the tip mounting member 27 is
As shown by an arrow T, the upper edge is narrowed down to the inner peripheral side so that the diameter is reduced uniformly, whereby the wall surface 28B of the chip mounting seat 28 is also reduced in diameter, so that the peripheral surface of the chip 29 is aligned with the central axis. As a result, the tip 29 is positioned so that its axis X coincides with the axis C of the tip mounting member 28.

Therefore, according to the rotary cutting tool having the above-described structure, the outer diameter dimension accuracy of the tip 29 is relatively rough, and the center axis of the tip 29 set at the time of design and the flank 29B of the manufactured tip 29 are formed. Even if there is a slight error between the true center axis X of the peripheral surface, that is, the center axis of the cutting blade 34, the true center axis X of the tip 29 is C, that is, the sheet 27 is positioned and attached so as to coincide with the center axis O of the rotating sheet 27. Therefore, even if the tip 29 having a small outer diameter tolerance is used, the rotation locus of the cutting edge 34 of the sheet 27 is Eccentricity from the center axis O can be suppressed, and deterioration of the machined surface roughness of the work material can be prevented. In other words, according to the rotary cutting tool, it is possible to perform high-precision machining using a relatively inexpensive tip 29. Therefore, the production cost of the disposable tip 29 can be reduced while maintaining the machining accuracy. It is possible to provide an economical rotary bite while suppressing it.

In this embodiment, the upper surface 2 of the sheet 26 is
A fitting hole 26D centering on the axis C is formed in 6C, and a fitting portion 27E that can be fitted in the fitting hole 26D is formed in the chip mounting member 27 around the axis C. When the chip mounting member 27 is elastically deformed in a state where is fitted, the bottom plate portion 27 of the chip mounting member 27 is
A sinks straight along the axis O with the fitting portion 27E being guided by the fitting hole 26D. Then, the peripheral wall 27B of the tip mounting member 27 is also uniformly reduced in diameter in the radial direction about the axis C coinciding with the axis O, thereby tightening the tip 29. The center of the cutting blade 34 can be accurately matched with the axes C and O, and the processing accuracy can be further improved. In addition, contrary to the present embodiment, a fitting hole may be formed on the chip mounting member side and a fitting portion may be formed on the sheet side, and the guide is not limited to such a hole. The tip mounting member may be elastically deformed along the axis O by means.

Further, in this embodiment, the sheet restraining member 3 for restraining the movement of the seat 26 in the direction of the axis O is provided at the lower end of the sheet 26.
1 to prevent the sheet 26 from dropping out of the sheet mounting hole 25 and dropping, or the sheet 26 swinging in the direction of the axis O during processing to deteriorate the processing accuracy. Can be. In addition, a countersunk screw 33 screwed to the sheet 26 is engaged with the chip attachment member 27 as a fall-off prevention member, thereby preventing the chip attachment member 27 from falling off the sheet 26 and the like. Therefore, handling at the time of unclamping can be further facilitated. In addition, since the flat head screw 33 does not interfere with the elastic deformation of the tip mounting member 27, the above-mentioned effect is not hindered at all.

Further, in this embodiment, the lower surface 27D of the chip mounting member 27 and the bottom surface 28A of the chip mounting seat 28, which is the upper surface, are both formed in a conical shape that is inclined downward toward the outer peripheral side. The gaps S ₁ and S ₂
This has the effect that the tip mounting member 28 can be reliably elastically deformed and the tip 29 can be positioned. In particular, since the bottom surface 28A is formed in a conical shape as described above, when the chip 29 is removed, the bottom surface 28A is in a state in which the chip 29 is pushed upward. Even when the chip 29 is firmly fastened to the peripheral wall 27B, there is an advantage that the chip 29 can be easily taken out.

However, the chip 29 and the chip mounting member 27
Dimensions, such as by the elastic deformation of the shape and the chip mounting member 29, it is also possible to the gap S ₁ is formed only on the lower surface 27D side of the chip mounting member 27.
In addition to the shapes of the lower surface 27D and the bottom surface 28A, in addition to the conical surface shape as in the present embodiment, for example, the lower surface 27D and the bottom surface 28A may be formed in a spherical shape having a center on the axis C. Depending on the shape, it may be formed in the shape of a pyramid. Further, in order to facilitate the elastic deformation of the tip mounting member 27, the bottom plate portion 27A and the peripheral wall portion 27B are provided.
Alternatively, a slit may be formed in the radial direction.

[0024]

As described above, according to the rotary cutting tool of the present invention, the tip is elastically deformed by pressing and fixing the tip by the clamping means, so that the axis of the tip coincides with the axis of the sheet. Since the insert is positioned so that it does not require a high level of skill in assembling parts, does not require strict accuracy of the insert itself, and does not decenter the cutting blade around the sheet axis. The tip can be rotated. Therefore, this makes it possible to reduce the manufacturing cost of disposable chips and reduce the cost of the tool while maintaining the processing accuracy of the tool.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a rotary tool according to the present invention in an unclamped state.

FIG. 2 is a sectional view of the rotary tool shown in FIG. 1 in a tip clamp state.

FIG. 3 is a side view showing a conventional rotary cutting tool.

FIG. 4 is a sectional view of the rotary tool shown in FIG. 3;

[Explanation of symbols]

 Reference Signs List 21 byte body 24 bearing member 25 sheet mounting hole 26 sheet 26D fitting hole 27 chip mounting member 27A bottom plate portion of chip mounting member 27B peripheral wall portion of chip mounting member 27E fitting portion 28 chip mounting seat 28A bottom surface of chip mounting seat 28 28B Wall surface of chip mounting seat 28 29 Throw-away chip 31 Sheet restraining member 33 Countersunk screw (dropping prevention member) 34 Cutting blade 35 Clamp screw (clamping means) O Central axis of sheet 26 C Central axis of chip mounting member 27 X Tip 29 Center axis of

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomoyoshi Sakamoto 1511 Furamagi, Ishishita-cho, Yuki-gun, Ibaraki Pref. Mitsubishi Materials Corporation Tsukuba Works (72) Inventor Sadaaki Watanabe 2 Takara-cho, Kanagawa-ku, Yokohama, Kanagawa Prefecture Sun (72) Inventor Kiyoshi Hasegawa 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture Nissan Motor Co., Ltd. (56) References Japanese Utility Model No. 2-51005 (JP, U) (58) Fields surveyed (58) Int.Cl. ⁷ , DB name) B23B 27/12 B23B 27/16 B23B 27/00 B23B 27/08 B23B 27/14

Claims (4)

(57) [Claims] 1. A rotary tool having a disc-shaped throw-away tip removably attached to a tip of a cutting tool body by a clamp means, wherein a sheet having a cylindrical shaft portion is provided at a tip of the cutting tool body. A tip mounting member is provided rotatably about the center axis of the shaft portion, and a chip mounting member having a bottom plate portion and a peripheral wall portion and having a chip mounting seat into which the throwaway chip is inserted is formed on the upper portion of the seat. It is detachably mounted the chip mounting seat as upward, and the upper portion of the sheet, on the sheet
Between the lower surface of the bottom plate portion of the chip mounting member facing the portion
When the indexable insert is not clamped,
And the distance increases from the outer circumference toward the center axis.
A gap is formed, and the gap is reduced by pressing the throw-away tip inserted into the tip mounting seat by the clamp means .
Rotary byte is urchin the chip mounting member clamping the peripheral wall portion is elastically deformed to the throw-away tip, characterized in that said throw-away tip is positioned. 2. A gap between a bottom surface of the tip mounting seat and a seating surface of the throwaway tip facing the bottom surface in a non-clamped state of the throwaway tip from the center axis side toward the outer periphery. 2. A gap having a large interval is formed, and the tip mounting member is elastically deformed so that the gap is reduced by pressing the throw-away tip by the clamping means. Rotary bite described. 3. The seat is mounted by fitting the shaft into a seat mounting hole provided in the tool body, and a lower end of the shaft is provided with the shaft in the seat mounting hole. claim, characterized in that the sheet restraining member for restraining the movement of the central axis direction is provided 1 or
A rotary tool according to claim 2 . 4. The sheet according to claim 1, wherein said sheet is provided with a falling-off preventing member which engages with said chip mounting member to prevent said chip mounting member from falling off said sheet. The rotary tool according to claim 3 .