JPH0744681U - Burnishing drill - Google Patents

Abstract

(57) [Abstract] [Purpose] To be able to simultaneously chamfer the opening of the pilot hole when drilling the pilot hole of the screw hole. [Structure] A chamfering blade that rises diagonally toward the handle portion is fixedly provided at the base of the cutting blade that is parallel to the axis, or the chamfering blade is provided so as to be adjustable forward and backward along the axis. . With the chamfering cutting blade provided at the rear portion of the cutting blade, the burr generated at the opening of the lower hole by the cutting blade can be cut off. Further, the depth of the prepared hole can be changed by adjusting the cutting edge for chamfering.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a burnishing drill capable of simultaneously chamfering the opening portion of a screw hole when drilling the pilot hole.

[0002]

[Prior art]

 Generally, there is a thread cutting method using a rolling tap as a method of forming a screw hole in a relatively soft metal such as aluminum or copper. This is a method in which a tap with pre-drilled holes is screwed in and the inner peripheral surface of the pilot hole is deformed under pressure to roll up the inner peripheral surface and roll the threads. Compared with the method of forming a thread by cutting the inner peripheral surface of the pilot hole with a general tap having a shape with several blade grooves, the machining accuracy is higher, the machining speed is faster, and the chips are However, since it is necessary to finish the inner peripheral surface of the pilot hole smoothly, it is necessary to drill the pilot hole as a pre-process when threading with a rolling tap. A burnishing drill that can simultaneously perform rough hole cutting and surface finishing of the inner surface is used. 8 and 9 are drawings showing a conventional burnishing drill. As shown in the drawing, a burnishing drill a is composed of a blade portion b and a handle portion c which are continuously arranged with the same diameter, and the blade portion b Has a plurality of blade grooves d cut parallel to the axis, and a cutting edge e is formed at the ridge of the groove d.

[0003]

[Problems to be solved by the device]

 However, using the burnishing drill as described above allows the inner peripheral surface of the hole to be cut smoothly, so that the preparation of the prepared hole and the surface finishing of the inner surface of the prepared hole can be performed simultaneously as described above. Although it is possible, even with such a burnishing drill, since a burr-like burr is inevitably generated at the opening of the prepared hole formed in the same way as a normal spinning drill, a spot facing is required to remove this burr. The actual situation is that further chamfering must be performed using a tool such as a drill. The present invention is an attempt to improve it in view of the conventional situation as described above, and an object of the present invention is to make it possible to chamfer the opening at the same time when the pilot hole is drilled. The point is to improve the work efficiency of forming the pilot hole, and the concrete means and action are as follows.

[0004]

[Means for Solving the Problems]

 At the base of the cutting edge parallel to the axis, a chamfering edge that rises obliquely toward the outer diameter direction is fixed or the same chamfering edge is provided so as to be adjustable forward and backward along the axis.

[0005]

[Action]

 The burr generated at the opening of the cutting hole due to the drilling of the pilot hole can be removed by the chamfering cutting blade provided at the base of the cutting blade.

[0006]

【Example】

 Specific embodiments of the present invention will be described below with reference to the accompanying drawings. 1 and 2 are drawings showing a first embodiment of the present invention, in which 1 is a burnishing drill, 2 is a blade portion thereof, and 3 is a handle portion. The blade portion 2 is composed of a small diameter portion 4 formed at the tip and a large diameter portion 5 connected to the small diameter portion 4, and an appropriate taper exists between the small diameter portion 4 and the large diameter portion 5 to provide an outer diameter. An inclined portion 6 that rises in the direction is provided. A flat surface is provided at a position that is 180 degrees in phase with the same blade portion 2, while two blades are provided from the tip of the small diameter portion 4 to the large diameter portion 5 at a position that is 90 degrees in phase with the flat surface. Grooves 7 are engraved parallel to the axis, and cutting edges 8 are formed on the small diameter portion 4 at the ridges of each blade groove 7, and chamfering edges 9 are formed on the inclined portion 6. .

3 to 6 are views showing a second embodiment of the present invention. The burnishing drill 1 is divided into a drill body 1a and a chamfering bit 1b. In the drill body 1a, the handle portion 3 is continuously provided on the blade portion 2 with the same diameter, and the two blade grooves 7 that form the cutting edge 8 at the ridge portion at the position where the blade portion 2 is 180 degrees in phase. While the chamfering bit 1b is engraved in parallel with the axis, a guide tube 10 formed into a cylindrical shape is externally fitted to the blade portion 2 of the drill main body 1a so that the guide tube 10 can be screwed into the guide tube 10. It is provided so that it can be fixed at an arbitrary position of the blade portion 2 by the bolt 11 of. At the front end of the guide cylinder 10, a pair of block pieces 12 are provided so as to project forward from a position 180 ° in phase, and at the front end of the block piece 12, an inclined portion 13 that rises diagonally is provided. A chamfering cutting edge 14 is formed on the ridge of the inclined and inclined portion 13. More specifically, the bolts 11 and 11 and the block pieces 12 and 12 are provided so as to be located on the same plane, and the tips of the bolts 11 and 11 are provided so as to abut the flat surface of the blade 2. The block pieces 12 and 12 are provided so as to be as close as possible to the flat surface of the blade 2 with a slight clearance. As a result, the tip end of the chamfering cutting edge 14 formed on the block pieces 12, 12 is provided so as to face the inside of the rotational trajectory of the cutting edge 8 formed on the ridge on the blade 2 side.

Next, the operation will be described. With the shank 3 of the burnishing drill 1 attached to a chuck such as a tapping machine or a turret lathe, the drill 1 is rotated to perform hole drilling work. A hole is bored by the cutting blade 8 of the small-diameter portion 4 and the burr generated at the opening of the hole is cut off by the chamfering cutting blade 9 of the inclined portion 6, and the chamfered portion is formed in the opening as shown in FIG. The holes 16 forming 15 can be drilled at one time. Further, in the second embodiment, the cutting blade 8 of the drill body 1a and the chamfering cutting edge 14 formed on the block piece 12 of the chamfering bit 1b are used as shown in FIG. In addition to the fact that a hole 16 for forming a chamfered portion 15 may be formed at one time in a large opening, the chamfered bit 1b may be moved back and forth along the drill body 1a to adjust the length of the cutting edge 8. Thereby, the effect of freely changing the depth of the hole 16 to be drilled can be obtained. Since the tip of the chamfering cutting edge 14 is provided on the inner side of the rotation path of the cutting edge 8 for cutting, the cutting load is applied to the tip end of the chamfering cutting edge 14. It never happens. That is, it is possible to prevent the tip of the cutting edge 14 for chamfering from spilling. In each of the first and second embodiments, the burnishing drill 1 forming the two blade grooves 7 is illustrated, but the blade grooves 7 are not limited to this number, and two or more blade grooves can be formed. It is also possible.

[0009]

[Effect of device]

 The present invention is constructed as described above, and is continuous with the base of the cutting edge that is parallel to the axis as described above, and has an appropriate taper to stand obliquely toward the outer diameter direction. By providing a chamfering cutting edge that can be raised, it is possible to drill the lower hole and chamfer the opening of the lower hole at the same time, and significantly improve the work efficiency when forming the lower hole of the screw hole. It came to be able to make it up. Further, in the second embodiment, the chamfering cutting edge that rises diagonally is provided so as to be adjustable forward and backward along the axis of the cutting edge, so that the preparation of the pilot hole and the opening portion as described above. The chamfering can be performed simultaneously and the depth of the prepared hole can be arbitrarily changed. In addition, it has become possible to prevent the tip of the chamfering cutting edge from spilling, which has made it possible to further improve its durability. Further, according to the present invention, the chamfering cutting edge is used to deeper the opening of the pilot hole to form not only the chamfer as described above but also a counterbore hole for sinking the head of the bolt. It was

[Brief description of drawings]

1 and 2 are views showing a first embodiment of the present invention,
FIG. 1 is a side view of the burnishing drill, and FIG. 2 is an enlarged front view of the same. 3 to 6 are views showing a second embodiment,
3 is a side view of the burnishing drill, FIG. 4 is a front view of the chamfering bit, FIG. 5 is an exploded perspective view of a part of the chamfering bit, and FIG. 6 is an enlarged sectional view taken along the line AA in FIG. FIG. 7 is a sectional view of a pilot hole drilled by the burnishing drill according to the present invention, FIG. 8 is a side view of a conventional burnishing drill, and FIG. 9 is an enlarged front view of the same.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Burnishing drill, 1a ... Drill main body, 1b ... Chamfering bit, 2 ... Blade part, 3 ... Handle part, 4 ... Small diameter part, 5 ... Large diameter part, 6 ... Inclined part, 7 ... Blade groove, 8 ... For cutting Cutting blades, 9 ... Chamfering cutting blades, 10 ... Guide tube, 11 ... Bolts, 12 ... Block pieces, 13 ... Inclined portions, 14 ... Chamfering cutting blades, 15 ... Chamfering portions, 16 ... Holes.

Claims (2)

[Scope of utility model registration request] 1. A burnishing drill, comprising a chamfering cutting edge that is inclined in the outer diameter direction and is provided at the base of the cutting edge that is parallel to the axis. 2. A burnishing drill comprising a cutting edge parallel to an axis and a chamfer edge rising obliquely toward the outer diameter direction so as to be adjustable forward and backward along the axis.