JPH0615922U - End mill - Google Patents

Abstract

(57) [Summary] [Object] To provide an end mill capable of continuously performing a drilling process and a cutting process of an inner periphery of a formed hole. [Structure] A pair of front cutting edges 4a, 4b are formed continuously with the outer circumferential cutting edges 3a, 3c at the tip of a main body 2 having four outer circumferential cutting edges 3a, 3b, 3c, 3d. The pair of front cutting edges 4a and 4b are inclined in opposite directions. Each front cutting edge 4
flanks 5a, 5b formed on the backs of a and 4b in the direction of rotation
The chisel edge 6 is formed at the intersection. A pair of front cutting blades 5a, 5b is used for boring, and the inner circumference of the formed hole is cut by outer cutting blades 3a, 3b, 3c, 3d.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an end mill suitable for machining an oval long hole.

[0002]

[Prior art and problems]

 As shown in FIG. 4, it has been common practice to insert a bolt 12 into an oblong hole 11 formed in a plate 10 and fix the plate 10 by tightening the bolt 12. .

In forming the long hole 11, conventionally, a circular hole is formed in a work by a drill, and then the inner circumference of the hole is cut by an end mill. It took a lot of time to replace.

[0004]

[Problems to be solved by the device]

 An object of the present invention is to provide an end mill that can efficiently perform oval hole drilling on a work.

[0005]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, in the present invention, in an end mill in which an even number of outer peripheral cutting edges are provided on a main body that is continuous with a shank, a pair of front cutting edges inclined in directions opposite to the tip of the main body is 180 °. A pair of front cutting blades are provided continuously at the tips of the two outer peripheral cutting blades facing each other with a space between the front cutting blades and a chisel edge is provided at the intersection of a pair of flanks formed on the back of the front cutting blades in the rotational direction. By adopting a configuration in which a steal is formed on the front side in the direction of rotation, the tip of the outer peripheral cutting edge, which is continuous with the front cutting edge, is positioned closer to the front end side of the main body than the tips of the remaining outer peripheral cutting edges.

[0006]

[Action]

 As described above, by providing a pair of front cutting edges that are inclined in opposite directions at the tip of the main body, it is possible to perform drilling with the front cutting edges, and the inner periphery of the formed hole is It can be cut by a peripheral cutting edge.

[0007]

【Example】

 An embodiment of this invention will be described below with reference to FIGS.

As shown in the drawing, the outer periphery of the main body 2 continuous with the shank 1 is provided with four outer peripheral cutting blades 3 a, 3 b, 3 c, 3 d, which are helical blades. A pair of front cutting blades 4a, 4b are formed at the tip of the main body 2 continuously from the tips of two outer circumferential cutting blades 3a, 3c facing each other with an interval of 180 °.

The pair of front cutting edges 4a, 4b are inclined in opposite directions, and the cutting edge angle α formed by the front cutting edges 4a, 4b is substantially the same as the tip angle of a normal drill used for drilling. Are made equal.

Further, flanks 5a and 5b are formed at the backs of the pair of front cutting blades 4a and 4b in the rotational direction, and a chisel edge 6 is provided at the intersection of the flanks 5a and 5b.

On the other hand, a rake face 7 is provided on the front side in the rotation direction of the pair of front cutting blades 4 a, 4 b, and an arc-shaped stab 8 is formed continuously with the rake face 7. The tips of the outer peripheral cutting blades 3b, 3d face the portion of the steal 8, and the tips are located on the shank 1 side from the tips of the outer peripheral cutting blades 3a, 3c continuous with the front cutting blades 4a, 4b.

Now, when the end mill is rotated, the end mill is moved toward the work so that the work can be perforated by the pair of front cutting edges 4a and 4b. At this time, the tips of the outer peripheral cutting edges 3b, 3d are located closer to the shank 1 than the tips of the outer peripheral cutting edges 3a, 3c that are continuous with the front cutting edges 4a, 4b. It has no effect.

After the drilling as described above, the end mill and the work are relatively moved in a direction orthogonal to the axis of the end mill, so that the inner circumference of the hole is the outer peripheral cutting edges 3a, 3b, 3c, 3d. By cutting with, it is possible to form an oblong slot 11 as shown in FIG.

[0014]

[Effect of device]

 As described above, in the end mill according to the present invention, the front end of the main body having the outer peripheral cutting edge is provided with a pair of front cutting edges continuous with the outer peripheral cutting edge, and the pair of front cutting edges are inclined in opposite directions. Therefore, the formation of the hole and the cutting of the inner periphery of the formed hole can be continuously performed, and the elliptical elongated hole can be formed extremely efficiently by a single tool.

[Brief description of drawings]

FIG. 1 is a front view of an end mill according to the present invention.

[Fig. 2] Bottom view of the above

FIG. 3 is a perspective view showing a tip portion of the same end mill.

FIG. 4 is a perspective view of a tightened member that is tightened by a bolt.

[Explanation of symbols]

 1 shank 2 main body 3a, 3b, 3c, 3d outer peripheral cutting edge 4a, 4b front cutting edge 5a, 5b flank 8 steal

Claims (1)

[Scope of utility model registration request] 1. An end mill in which an even number of outer peripheral cutting edges are provided on a main body connected to a shank, and a pair of front cutting edges inclined in directions opposite to the tip of the main body are opposed to each other at 180 ° intervals. Provided continuously to the tip of the outer peripheral cutting edge, a chisel edge is provided at the intersection of a pair of flanks formed on the back in the rotational direction of each front cutting edge, and a steal is formed on the front side in the rotational direction of the pair of front cutting edges. An end mill characterized in that the tip of an outer peripheral cutting edge continuous with the front cutting edge is located closer to the tip side of the main body than the tips of the remaining outer peripheral cutting edges.