JP2670082B2 - Turning tool - Google Patents

Description

TECHNICAL FIELD The present invention relates to a cutting tool that performs a turning process in an NC lathe or a single function, and more particularly to a cutting tool for turning the back surface of a workpiece gripped by a chuck.

[Prior Art] Conventionally, when a stepped hole as shown in FIG.
When it is desired to form a large-diameter recess L on the surface (side that is gripped by 51), after forming a small-diameter hole S with a hole machining bit,
Insert the cutting tool 52 shown in FIG.
It was turning from the side.

[Problems to be Solved by the Invention] By the way, due to strength and other problems, the length a1 of one side of the tip 53 attached to the cutting tool 52 cannot be reduced to a predetermined value or less. However, in the bite 52, the tip 53 has a flat rhomboid shape and the blade portion 55 of the tip 53 has a cutting edge angle θ2 of approximately 90 degrees.
The work W is turned. That is, the dimension d1 of the chip 53 in the thickness T direction of the holder 54 becomes almost twice the length a1 of one side of the chip 53. Therefore, even when the length a1 of one side of the tip 53 is minimized as much as possible, the tip 52 in the thickness T direction of the cutting tool 52
The dimension d1 of 53 becomes large, and the dimension D1 in the thickness T direction of the cutting tool 52 also becomes large. As a result, when it is desired to reduce the inner diameter of the recess L to a predetermined value or less, the inner diameter of the hole S also decreases accordingly, so that the cutting tool 52 cannot be inserted into the hole S and the recess L is formed on the back surface B of the work W. There is a problem that it cannot be formed.

Further, in this conventional turning tool 52, in order to insert the insertion portion of the holder 54 into the hole S, the diameter of the hole S must be larger than the dimension D1 in the thickness T direction. There is also a problem that turning cannot be performed unless the diameter of the hole S is large.

The present invention provides a turning tool capable of finishing the back surface of a work having a small diameter hole and easily forming a recess having a small inner diameter on the back surface of the work as compared with a conventional turning tool. It is intended to be.

Another object of the present invention is to provide a turning tool capable of easily inserting the insertion portion of the holder even with a small diameter hole and ensuring a sufficient turning area of the chip.

[Means for Solving the Problems] In order to achieve the above object, according to the invention of claim 1, one chip having a flat equilateral triangle shape is attached so that a central position thereof is closer to one side of the insertion portion of the holder. One of the blades provided on each side of the insert is arranged so as to face the holder base end side and the tip is projected from one side surface of the insertion part in the thickness direction, while The width of the direction is narrower than the width of the supporting portion, the blade portion of the same tip so as not to protrude outward than the width of the supporting portion, the position of the blade portion near the longitudinal center of the insertion portion. Placed. Further, in the invention of claim 2, in addition to the structure of claim 1, the tip has a cutting edge angle larger than 90 degrees.

[Operation] In the turning tool according to claim 1 configured as described above, the size of the chip in the thickness direction of the cutting tool becomes small, and the size of the cutting tool in the thickness direction also becomes small. Further, since the insertion portion is narrower than the support portion, even a small hole which cannot be formed by a turning tool having a support portion having the same diameter as before can be inserted and processed. Further, since the blade portion of the tip does not protrude beyond the width of the support portion, the tip does not come into contact with the periphery of the hole when the insertion portion is inserted into the hole. Further, since the insert portion has a small diameter with respect to the support portion and the tip is moved outward in the thickness direction by the thickness thereof, the tip is turned even if it does not largely protrude in the thickness direction of the support portion as in the conventional case. The area is secured. Further, since the blade part of the tip for turning the work is located just in the vicinity of the center of the insertion part, the bending of the insertion part is suppressed by the action of the inertial force on the tip side of the insertion part.

According to the second aspect of the invention, in addition to the function of the first aspect, the dimension of the chip in the thickness direction of the holder can be further reduced.

[Embodiment] An embodiment in which the present invention is embodied in a turning tool used for a single function will be described below with reference to the drawings.

As shown in FIG. 1, a chuck 2 is attached to the tip of a rotary shaft 1 of a rotary drive mechanism (both not shown) of the lathe body so that the chuck 2 and the rotary shaft 1 can rotate together. The work W is gripped. A support plate 5 that supports the cutting tool 4 is provided at a position facing the chuck 2 so as to be movable in the front-rear direction (left and right in FIG. 1) and in the left-right direction.
Is for turning a workpiece W into a desired shape.

As shown in FIGS. 2 to 5, in the cutting tool 4 of the present embodiment, the holder 6 is a support portion 7 fixed to the support plate 5,
The workpiece W extends in the axial direction from the support portion 7 during turning.
The insertion portion 8 is inserted into the hole S of the. A chip 11 having a flat equilateral triangle shape is detachably mounted by a socket bolt 10 in a mounting recess 9 formed in the insertion portion 8. The width of the insertion section 8 in the thickness direction is smaller than that of the support section 7.

Then, one of the blades 12 for turning the workpiece W provided on each side of the tip 11 is cut at a cutting angle θ1 larger than 90 degrees.
Is arranged so as to face the support portion 7 side (the base end portion side of the holder 6) and is projected from one side surface of the insertion portion 8 in the thickness T direction of the holder, and the blade portion 12 The back B can be turned. The blade 12 of the tip 11 does not protrude in the thickness direction of the support 7.

The blade 12 of the tip 11 is located approximately in the center of the insert 8. 5th to 7th steps of turning the concave portion L on the back surface B of the work W using the turning tool 4 configured as described above
Description will be made with reference to the drawings.

First, after forming a hole S in the work W by a well-known hole cutting tool, as shown in FIG. 5, the support plate 5 is moved forward (to the left in FIG. 5) to insert the cutting portion 8 of the cutting tool 4. The hole S
The tip 11 of the tip 11 is brought into contact with the position P corresponding to the outer periphery of the recess L to be turned on the back surface B of the work W by inserting the chip 11 from the back surface B of the work W to expose the tip 11. Then, as shown in FIG. 6, the work W is turned to a desired depth while moving the cutting tool 4 rearward through the support plate 5. Thereafter, as shown in FIG. 7, the cutting tool 4 is moved to the right (upward in FIG. 7) to form a recess L having a desired shape in the work W.

As described above, in the present embodiment, the chip 11 has a planar regular triangular shape. Therefore, the dimension d2 of the chip 11 in the thickness T direction of the holder 6 is the length of one side of the chip 11
The dimension D2 in the thickness T direction of the cutting tool 4 can be reduced without being larger than a2. Further, since the chip 11 of this embodiment has a cutting angle θ1 exceeding 90 degrees,
The dimension d2 of the chip 11 in the thickness T direction of the holder 6 and thus the dimension D2 of the cutting tool 4 are further reduced. As a result, it is possible to form the recess L having a small inner diameter, which is difficult to form on the back surface B of the work W with the conventional cutting tool 52.

It should be noted that the present invention is not limited to the above embodiment, and it is of course possible to embody the present invention in the following modes.

(1) Use the above-mentioned cutting tool 4 in an NC-controlled lathe.

(2) The above embodiment is embodied as a bite of the type in which the tip 11 is fixed to the holder 6 by the bolts 10, but the present invention may be embodied as a clamp fixed type or pin fixed type bite.

[Advantages of the Invention] In the present invention, even a small hole which cannot be machined by the conventional turning tool can be inserted and machined.
Also, since the blade part of the tip does not protrude in the thickness direction of the support part, the tip will not contact the periphery of the hole when inserting the insert part into the hole. Since the tip can be moved outward in the thickness direction by the thickness reduced by the diameter, the area where the tip is turned is secured even if the tip does not largely protrude in the thickness direction of the support as in the conventional case.

Further, since the blade part of the tip for turning the work is just near the center of the insertion part, the bending of the insertion part is suppressed by the action of the inertial force on the tip side of the insertion part, which contributes to the improvement of the turning accuracy.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of an essential portion showing a state in which a cutting tool according to an embodiment of the present invention is attached to a unipot machine, FIG. 2 is a plan view showing a cutting tool, FIG. 3 is a side view of the same, and FIG. FIG. 5 is an enlarged perspective view showing the tip, FIG. 5 is a partial plan sectional view showing a state where the tip is in contact with a work, and FIG. 6 is a partial plan sectional view showing a state where the tip is moved backward from the state shown in FIG. FIG. 7 is a partial plan sectional view showing a state where the tip is moved to the right from the state shown in FIG. 6, and FIG. 8 is a partial plan sectional view showing a conventional cutting tool. Holder 6, chip 11, blade 12, thickness T.

Claims (2)

(57) [Claims] 1. A chip (11) of a regular equilateral triangle shape is attached so that its center position is near one side of an insertion part (8) of a holder (6) and is provided on each side of the chip (11). One of the blade parts (2) is arranged so as to face the base end side of the holder (6) and is projected from one side surface of the insertion part (8) in the thickness (T) direction, while the same. The width of the insertion part (8) in the thickness direction is made narrower than the width of the support part (7), and the blade part (12) of the tip (11) is located outside the width of the support part (7). A turning tool characterized in that the position of the blade portion (12) is arranged near the center in the longitudinal direction of the insertion portion (8) so as not to protrude. 2. The turning tool according to claim 1, wherein the tip (11) has a cutting edge angle (θ2) of more than 90 degrees.