JPH0618732Y2 - Ball end mill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a blade type ball end mill, and is particularly suitable for machining a die, a graphite electrode for a die, and the like.

(Prior Art) Conventionally, as this type of ball end mill, those found in, for example, Japanese Utility Model Publication No. 63-120716 and Japanese Utility Model Publication No. 62-178015 are disclosed.

In the former publication, the chip plate and the regulating member are arranged in the mounting groove and they are sandwiched by bolts. The latter publication is a throw-away type in which the central member is made of cemented carbide, and has an oil supply hole formed in its axial direction.

(Problems to be solved by the invention) However, in the former case, the concave shape of the chip plate increases the depth of the mounting groove, resulting in low tool rigidity, and it is impossible to provide an oil supply hole. There was a problem.

In the latter case, it is a throw-away type.
Depending on the machining application, a blade type that allows re-grinding is also required due to its mounting accuracy, blade edge shape, etc.

In view of the above, the present invention intends to provide a ball end mill, which is intended for a blade type and whose tool rigidity is enhanced and an oil supply hole is configured.

(Means for Solving the Problems) The ball end mill of the present invention has been made in view of the above-mentioned points, and the cutting blade is positioned in the radial direction in the slit provided in the tip round head of the tool body. It is arranged such that it is arranged via a piece, the positioning piece is attached by a set screw, and the cutting blade is attached by a tightening bolt.

That is, in the tool body, a mounting hole for receiving the narrow portion of the positioning piece is bored in the axial direction on the bottom surface of the slit, and this mounting hole communicates with the supply hole for the refrigerant. A screw hole for receiving the set screw and an injection hole directed to the slope of the chip pocket are provided in series, and a mounting hole for receiving the tightening bolt is provided in a direction traversing the slit.

Further, in the cutting blade, a pair of cutting edge ridges having a 1/4 circle shape is formed at the tip end portion located on the chip pocket side, and a rectangular mounting groove is formed at the rear end portion. By doing so, it has a substantially U-shape.

Further, the positioning piece has flat upper and lower surfaces whose thickness is substantially the same as the thickness of the cutting blade, and the outer shape thereof is a block shape having a substantially convex diameter composed of a wide portion and a narrow portion. To present. Then, a through hole for receiving the tightening bolt is bored in the wide portion, and when located in the mounting groove of the cutting blade, its arcuate outer surface is brought into contact with the inner surface in the mounting groove. It is one that has become. On the other hand, when it is located inside the mounting hole that is connected to the narrow portion slit, its arcuate outer surface contacts the inner peripheral surface of the mounting hole, and the remaining upper and lower surfaces form the injection hole and the screw hole. An arcuate internal space is formed between the mounting hole and the mounting hole.

(Operation) In the ball end mill of the present invention, the cutting blade in the mounting groove is incorporated together with the positioning piece, and is clamped and fixed by the tightening bolt. Therefore,
The positioning of the cutting blade in the radial direction is performed by the side surface of the wide portion of the positioning piece.

Further, in the ball end mill of the present invention, oil is supplied from the supply hole through the injection hole from the internal space existing between the upper and lower surfaces of the positioning piece and the mounting hole.

(Embodiment) An embodiment of the ball end mill of the present invention will be described below with reference to the drawings.

1 to 4, (1) is a cylindrical tool body, and a shank portion (2) is formed at the rear end thereof. The tip of the tool body (1) has a chip pocket (5) with a diametrical slit (3) and a bevel (4).
Are formed.

Inside the slit (3), the cutting blade (6) and the radial positioning piece (7) are arranged, and the tightening bolt (1
Fixed by 5) and set screw (9). And, this cutting blade (6) has a pair of 1/4 circular cutting edges.
(8) is formed. In this case, the pair of cutting edge ridges (8) are formed on the cutting edge tip (10) attached to the blade base metal (9) in the illustrated case. In addition, this cutting edge tip
(10) is generally formed of cemented carbide, cermet, ceramics, or the like, but may be formed of a composite tip made of a polycrystalline sintered body such as diamond or cubic boron nitride. . This enables especially high speed cutting,
Suitable for high efficiency machining in graphite electrodes for electrical discharge machining.

Also, at the rear end of the cutting blade (6), a rectangular mounting groove
(11) is formed so that it has a substantially U shape.

Further, the positioning piece (7) described above is composed of a wide portion (7a) and a narrow portion (7b) having a through hole (16), and the outer shape thereof is a substantially convex block shape. . And, the positioning piece (7), the thickness of which is substantially the same as the cutting blade (6), the upper and lower surfaces (12) (13) present a flat surface, the wide portion (7a) and the narrow portion Both outer sides of (7b) (14)
But has an arc shape.

Therefore, as described above, the positioning piece (7) includes the tightening bolt (15) and the set screw (19) with respect to the tool body (1).
It is fixed by, at that time, the cutting blade (6)
The wide portion (7a) is located in the mounting groove (11). Then, the outer surface (14) of this wide portion (7a) is the cutting blade (6).
It is positioned by contacting the inner surface of the mounting groove (11). In this case, the wide portion (7a) can be eccentric to the narrow portion (7b).

Then, the narrow part (7b) of the positioning piece (7) is
It is inserted into the mounting hole (17) formed in the center of the bottom surface of (3). And this mounting hole (17) is
It communicates with the coolant supply hole (18) provided in the axial center line portion of (1). Also, set screw (19) in this mounting hole (17).
Bevels (4) for receiving screw holes (20) and chip pockets (5)
The injection holes (21) that open toward each side are connected in series. Therefore, the positioning piece (7) should be placed in this mounting hole (17).
When the narrow part (7b) of the
(13) forms an arcuate internal space between the injection hole (21) and the mounting hole (17) in which the screw hole (20) is opened. Therefore, the refrigerant is supplied from the supply hole (18) through this internal space toward the injection hole (21) and to the cutting edge (8).

In the ball end mill of the present invention thus constructed, the cutting blade (6) is clamped and fixed by the tightening bolt (15). Therefore, the mounting hole (22) for receiving the tightening bolt (15) is provided in the direction crossing the slit (3), and the screw hole (20) for receiving the set screw (10) is formed in the tool body (1). It is provided so as to intersect the mounting hole (17) from the side surface.

(Effects of the Invention) As described above, the present invention provides that when the cutting blade (6) is clamped by the tightening bolt (15) in the slit (3), the radial positioning piece () having a specific shape ( Since it considers 7), it has the following effects.

Firstly, the cutting edge brake (6) is accurately incorporated. This is because the axial position of the cutting blade (6) is given by the bottom surface of the slit (3), and the radial position is determined by the outer surface (14) of the wide portion (7a) of the positioning piece (7). Because it is given.

Secondly, the cutting blade (6) has a high mounting rigidity and can supply the refrigerant well. This is that the depth of the slit (3) described above can be made shorter than the above-mentioned Japanese Utility Model Laid-Open No. 54-29489 by merely matching the length of the cutting blade (6) and the injection hole for the refrigerant ( This is also because 21) does not have to be so long.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the ball mill of the present invention,
FIG. 2 is a bottom view of the same, FIG. 3 is a perspective view of an essential part, and FIG.
The figure is an exploded perspective view. (1) …… Tool body, (3) …… Slit (4) …… Slope, (5) …… Chip pocket (6) …… Cutting blade, (7) …… Positioning piece (8) …… Cut Edge (11) …… Installation groove (12) …… Upper surface, (13) …… Lower surface (14a) (14b) …… Side surface, (15) …… Tightening bolt (16) …… Through hole, (17 ) …… Mounting hole (18) …… Supply hole, (19) …… Set screw (20) …… Screw hole, (21) …… Injection hole (22) …… Mounting hole

Claims (1)

[Scope of utility model registration request] 1. A tool body (1) is provided with a diametrical slit (3) and a chip pocket (5) in a rounded head, and a cutting blade (6) is provided in the slit (3). Is placed via the radial positioning piece (7), the positioning piece (7) is attached by the set screw (19), and the cutting blade
(6) is a ball end mill that is attached by tightening bolts (15), wherein the tool body (1) has a narrow portion (7b) of the positioning piece (7) on the bottom surface of the slit (3). ) Is formed in the axial direction, and this mounting hole (17) communicates with the supply hole (18) for the refrigerant, and this mounting hole (17) has a set screw (1
Bezel of screw hole (20) to receive 9) and chip pocket (5)
Injection holes (21) toward (4) are connected in series, and further tightening bolts (1
A mounting hole (22) for receiving 5) is provided, and the cutting blade (6) has a 1/4 circular shape at the tip portion located on the chip pocket (5) side. A pair of cutting edges (8) is formed, and a rectangular mounting groove (1
1) is formed to have a substantially U-shape, and the positioning piece (7) has a flat upper and lower surface so that the thickness thereof substantially matches the thickness of the cutting blade (6). (12) has a (13), the outer shape is a substantially convex block shape consisting of a wide portion (7a) and a narrow portion (7b), the wide portion
A through hole (16) for receiving the tightening bolt (15) is formed in (7a), and when located in the mounting groove (11) of the cutting blade (6), its arcuate outer surface (14a). Mounting groove (11)
When the narrow portion (7b) is located inside the mounting hole (17), the arc-shaped outer surface (14a) is attached to the mounting hole ( It is abutted against the inner peripheral surface of 17), and the remaining upper and lower surfaces (12) (13) have an arcuate internal space between the injection hole (21) and the mounting hole (17) equipped with the screw hole (20). The set screw (19) is screwed into the screw hole (20) of the tool body (1) to screw the narrow portion (7b) of the positioning piece (7). The tightening bolt (15) is attached to the mounting hole (22) of the tool body (1).
And a ball end mill which is fitted into the through hole (16) of the positioning piece (7) so that the cutting blade (6) can be clamped in the slit (3).