JP4979093B2 - Center drill bit - Google Patents

Description

The present invention relates to a center drill bit, and more particularly to a center drill bit that sandwiches a center bit.

As shown in FIG. 10, the conventional center bit 50 is a circular casing, drill heads are formed at both ends, and a part of the handle diameter 51 of the circular casing attached in the chuck is used for tightening and clamping. Has no other function. In general, the pattern diameter 51 of the central bit increases as the size of the blade diameter 52 increases. For example, when the blade diameter is 1.6 mm, the handle diameter is 4 mm, when the blade diameter is 4 mm, the handle diameter is 10 mm, and when the blade diameter is 10 mm, the handle diameter is 25 mm. Moreover, the larger the handle diameter 51 is, the more material is used. Therefore, most of the center bits use high speed steel (HSS) as a material in order to reduce the cost.

However, when high speed steel is used as the material, there is a limit to the cutting speed. In order to obtain high efficiency and high quality, shorten the process time, and improve the cutting speed, the material of the drill bit is very important. Increasing the material strength of the central bit can increase the rotational speed and the feed rate of the drill. For example, when a drill bit is made of tungsten carbide, its processing speed is 5 to 20 times that of high-speed steel (depending on the processing material), but its cost is 10 times or more that of high-speed steel. Become. For the central bit, the handle diameter 51 was larger than the blade diameter 52, the material cost used for the handle diameter 51 was very high, and the market selling price was very high (about NT $ 20,000). That is, since the material cost occupies most of the entire cost, the center bit made of tungsten carbide as a whole was very few.

In the conventional center bit, the handle diameter is larger than the blade diameter, so that there are a lot of materials that are not used. In addition, since most of the material is made of a high-speed steel material, there has been a limit to improving the cutting speed and processing speed.

An object of the present invention is to provide a center drill bit that improves the cutting ability and processing speed of the center drill and reduces cost and processing time.

In order to solve the above-mentioned problems, according to a first embodiment of the present invention, a drill bit body and a center drill bit including a center bit, the drill bit body has a blade provided with a center blade stand. A screw hole is provided in the central blade piece base, pin holes are provided on both sides of the screw hole, respectively, and the pin hole is located in half in the central blade piece base; Positioning pins are inserted into the holes, the center blade stool has flat sides on both sides, and each of the flat sides is provided with a gradually narrowing oblique side surface connected to the center positioning groove, The center bit has a flat shape that can be accommodated in the center blade piece base of the drill bit body, has a fixing hole, and positioning grooves that can be fitted to the positioning pins on both sides of the fixing hole. Are provided, and screws are inserted into the fixing holes. When the center bit is installed and screwed into the screw hole, the center bit is fixed to the central cutting edge of the drill bit body, and another flat side corresponding to the central cutting edge is provided on both sides of the central bit. Are provided, a cutting edge is provided at an end of the central bit, and a tapered blade having a cutting waste discharging groove is provided between the cutting edge and the other flat side. A central drill bit is provided.

The center drill bit of the present invention can improve the cutting ability and processing speed of the center drill, and can reduce cost and processing time.

It is a perspective view which shows the center drill bit by one Embodiment of this invention. It is a front view which shows the center drill bit by one Embodiment of this invention. It is a front view which shows the drill bit main body by one Embodiment of this invention. It is a front view which shows the center bit by one Embodiment of this invention. It is a front view which shows a state when combining a center bit with the drill bit main body by one Embodiment of this invention. It is a schematic diagram which shows the center bit by one Embodiment of this invention, and the center hole formed with the drilling angle of 60 degrees. It is a schematic diagram which shows the center hole formed by the combination of the center bit by one Embodiment of this invention, the drilling angle of 60 degrees, and the drilling angle of 120 degrees. It is a schematic diagram which shows the center bit by one Embodiment of this invention, and the center hole formed by the drilling arc R angle | corner. It is the elements on larger scale which show a state when pressing a center bit with a stick according to this embodiment. It is a schematic diagram which shows the conventional center bit.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited thereby.

Please refer to FIG. 1 and FIG. As shown in FIGS. 1 and 2, a center drill bit according to an embodiment of the present invention includes a drill bit body 1 and a center bit 30. The drill bit body 1 includes a sword handle 10 and a blade 20. The shape of the sword handle 10 may be a straight blade shape or a taper shape depending on the necessity of the sword shaft to be attached. The blade 20 has a central blade base 21. The central blade base 21 is provided with a screw hole 221. Stepped pin holes 222 are provided on both sides of the screw hole 221. Half of the pin hole 222 is located on the central blade base 21 and the other half is located on the blade 20. The pin hole 222 is used for fitting the positioning pin 23, and the central blade base 21 has (vertical) flat sides 211 of an appropriate length on both sides thereof, and gradually narrows toward the upper side. A hypotenuse surface 212 connected to the positioning groove 213 is provided. The central blade base 21 is used to store a flat central bit 30 corresponding to the shape of the central blade base 21. The main body of the center bit 30 has a flat shape, and a fixing hole 31 is provided at the center. On both sides of the fixing hole 31, a semicircular cutout positioning groove 32 is provided. The center bit 30 has a flat side 33 at the upper and lower portions of the positioning grooves 32 provided on both sides, and has a cutting edge 34 at the end. A tapered blade 35 having a cutting waste discharge groove 350 is provided between the cutting edge 34 and the flat side 33. The shape of the taper blade 35 may be an arc taper (shown in FIG. 8) or a polygonal taper (shown in FIGS. 6 and 7) in which different angles are combined in addition to the straight-side taper.

<Quick positioning function when attaching center bit>
(1) Left and right quick positioning Refer to FIG. 1 and FIG. As shown in FIGS. 1 and 2, positioning pins 23 can be fitted on the flat sides 211 provided on both sides of the central blade base 21. Further, the positioning grooves 32 provided so as to correspond to both sides of the center bit 30 can absorb the dimensional tolerance. Therefore, when the center bit 30 is fitted, positioning can be performed very accurately, and there is no need to reposition or correct the blade crossing direction of the cutting edge 34 and the position of the cutting edge. As a result, it is possible to save the work time for correcting the position, shorten the machining time, and improve the production efficiency.

The center bit 30 can also be positioned by the flat straight sides 211 provided on both sides of the center blade base 21 in addition to being able to quickly position by the positioning pin 23. The distance between the flat sides 211 is substantially the same as the distance between the flat sides 33 at the upper and lower portions of the positioning groove 32 provided on both sides of the center bit 30 so that the dimensional tolerance can be absorbed. . Thereby, the center bit 30 can be accommodated in the center blade base 21 and positioned.

Further, the cutting edge 34 of the center bit 30 is attached to the center positioning groove 213 of the center blade piece base 21 to perform positioning and absorb the dimensional tolerance. That is, the center bit 30 can be quickly and accurately fitted into the center blade piece base 21 by positioning the guide by positioning the cutting edge 34 with the center positioning groove 213.

When the center bit 30 which is the above-described three types of positioning structures is fitted into the center blade piece base 21, it is quickly fixed on the left and right sides.

(2) Fastening and positioning in the vertical direction Refer to FIG. 3 and FIG. As shown in FIGS. 3 and 4, the screw hole 221 and the pin hole 222 of the central blade base 21 according to the embodiment of the present invention are slightly displaced in the vertical direction at a minute interval e. The center position of 221 is slightly higher than the center position of the pin holes 222 (or positioning grooves 32) on both sides (the distance e in this embodiment is about 0.15 mm). Therefore, when the center bit 30 is fitted in the center blade base 21, the center position of the fixing hole 31 is 0.15 mm lower than the center position of the screw hole 221, and the screw 40 (shown in FIGS. 1 and 5 is inserted in the screw hole 221). ), The fixing hole 31 is pressed upward by the screw head 41, and the positioning pin 23 comes into close contact with the positioning grooves 32 provided on both sides of the center bit 30 (shown in FIG. 2). (FIG. 5 shows the axial force acting on the center bit 30 when cutting), and when the screw 40 is fastened to the center blade base 21, the center bit is 30 are simultaneously positioned in the vertical direction.

Therefore, the center bit 30 can be fixed by restraining the top and bottom, left and right, front and back, and the rotation direction, and can be positioned conveniently and quickly, and the force receiving distribution of cutting is preferable.

<Material volume of center drill>
In general, the conventional center drill uses a high-speed steel material, so that the cost is very high. However, since the center bit 30 of the center drill bit according to one embodiment of the present invention uses tungsten steel having a very high strength as the main material of the main body, it improves the cutting ability and processing speed of the center drill, Cost and processing time can be reduced. Since the center drill body has a flat body shape, it is smaller than the conventional cylindrical center drill, the material cost is reduced, and the center drill bit can be used repeatedly. Therefore, the manufacturing cost of the center bit 30 can be reduced, the center drill made of tungsten steel can be widely spread, and the cutting efficiency of the center drill can be improved.

<Center drill bit consisting of a combination of multiple angles>
Reference is made to FIGS. As shown in FIGS. 6-8, the shape of the taper blade 35 of the center bits 30 and 30A of this embodiment has several aspects. FIG. 6 is a schematic diagram showing a center hole 351 formed by the taper blade 35 at a drilling angle of 60 °. FIG. 7 is a schematic diagram showing a polygonal pyramid-shaped center hole 352 formed by a combination of the taper blade 35 and the top blade 36 at a drilling angle of 60 ° and a drilling angle of 120 °. FIG. 8 is a schematic diagram showing a state when the arcuate conical center hole 353 is formed by the center bit 30 </ b> A having the arcuate taper blade 37. If necessary, center bits 30 and 30A having different shapes can be combined to cut center holes having various shapes.

Please refer to FIG. 1, FIG. 3 and FIG. As shown in FIGS. 1, 3 and 9, the center blade base 21 is provided with a blade hole 223 of the blade 20, and the blade provided at the bottom of the blade 20 when the center bit 30 is replaced in advance. By pressing the center bit 30 by penetrating the rod 224 (or other tool) in the hole 223, it is possible to prevent the center bit 30 from being damaged and being unable to be removed from the center blade base 21. The center bit 30 can be removed smoothly and quickly from the center blade stand 21.

As can be seen from the above, the center drill bit of the present invention can quickly position the center drill with the positioning pins, and can quickly attach and detach the center drill. The positioning grooves in the center of the flat sides or the ends of the both sides of the central blade stand have a function of quickly positioning the central bit, and the central bit is fastened by screws to position the central drill bit. By forming the main body of the center bit in a flat shape, the material can be saved and the cost can be effectively reduced, and the cutting ability can be improved by using a material having high hardness for the center bit.

While the preferred embodiments of the present invention have been disclosed above, as may be appreciated by those skilled in the art, they are not intended to limit the invention in any way. Various changes and modifications can be made without departing from the spirit and scope of the present invention. Accordingly, the scope of the claims of the present invention should be construed broadly including such changes and modifications.

DESCRIPTION OF SYMBOLS 1 Drill bit main body 10 Sword pattern 20 Blade 21 Center blade piece base 23 Positioning pin 30 Center bit 30A Center bit 31 Fixing hole 32 Positioning groove 33 Flat edge 34 Cutting edge 35 Taper edge 36 Top edge 37 Arc-shaped taper edge 40 Screw 41 Screw head 50 Center bit 51 Handle diameter 52 Blade diameter 211 Flat side 212 Slope side 213 Center positioning groove 221 Screw hole 222 Pin hole 223 Blade hole 224 Barbed rod 350 Cutting waste discharge groove 351 Center hole 352 Polygonal pyramid center hole 353 Arc conical center hole e Interval

Claims (1)

A center drill bit comprising a drill bit body and a center bit,
The drill bit body has a blade provided with a central blade piece, the central blade piece is provided with a screw hole, and pin holes are provided on both sides of the screw hole. Half of the hole is located in the central blade stand, a positioning pin is fitted in the pin hole, the central blade stand has flat sides on both sides, and each of the flat straight sides includes: A gradually narrowing hypotenuse connected to the center positioning groove is provided,
The center bit has a flat shape that can be accommodated in the center blade piece base of the drill bit body, has a fixing hole, and positioning grooves that can be fitted to the positioning pins on both sides of the fixing hole. Are provided, and the center bit is fixed to the central cutting edge of the drill bit body when a screw is passed through the fixing hole and screwed into the screw hole. Another flat straight side corresponding to the center blade stand is provided, a cutting edge is provided at an end of the central bit, and a cutting waste is provided between the cutting blade and the other flat straight side. A center drill bit, characterized in that a tapered blade having a discharge groove is provided.