JPS6128657Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a drill reamer that can perform drilling and reaming simultaneously with one tool.

When drilling a valve guide hole in a workpiece with a large machining allowance, such as the cylinder head of an engine made of aluminum alloy casting, the drilling position is on a slope, so when the drill bits in, cutting resistance from the side will cause The drill may tilt.

To ensure centering of the drill, you can use a stepped drill, but even then, when the large diameter part of the attached drill bits into the workpiece, cutting resistance is received from the sides, so it is difficult to center the drill at the small diameter part. The drill sometimes tilted.

After drilling a hole, use a reamer to finish the inner surface of the pilot hole, but if the drill is tilted as shown above, the reamer will follow the tilted pilot hole.
There is a problem where the axis of the hole is inaccurate.

The present invention solves the above-mentioned problems at the start of drilling, and at the same time eliminates the need for pilot hole drilling and performs drilling and reaming in one step, making it highly efficient.In addition, the tip of the cutting edge can be easily ground, making it possible to create accurate holes. The purpose is to provide a tool that can be opened.

In other words, in a drill reamer in which four twisted grooves are provided and two twisted drill bits and two reamer twisted bits are arranged alternately, the tip shape of the cutting edge of the drill bit is shaped like a tail, and the tip shape of the cutting edge of the drill bit is shaped like a tail. The chamfered part of the blade is formed into a sword-point shape, and the tail-fin-shaped cutting edge and the sword-point-shaped chamfered part intersect at a substantially right angle, and the apex of the sword-point-shaped chamfered part of the twisted blade for reaming is
The fluke-shaped cutting edge of the twisted drill bit for a drill is made to protrude from both ends to serve as a chisel point for the drill, and both ends of the chisel-shaped part of the twisted blade for a reamer are made to protrude from both ends of the tail-fin-shaped cutting edge of the twisted drill bit. The gist is that it has been retreated.

The structure of the drill reamer of the present invention will be explained below with reference to the embodiment shown in the drawings. 1 is a tool body, 2 is a shank, and by providing four helical grooves 3 in the main body 1, a helical drill bit 4 and a reamer are formed. Two twisted blades 5 are arranged alternately.

The tip cutting edge 44 (shown in the fifth figure) of the helical drill bit 4 is formed into a tail fin shape. The inclination of the caudal fin-shaped concave can be about 5 degrees.

The biting part 51 of the twisted blade 5 for reaming is in the shape of a sword, and its tip angle is the same as the cutting blade of a general drill.
Approximately 118° is acceptable.

The flute-shaped cutting edge 44 at the tip of the twisted drill bit 4 and the tip-shaped biting part 51 at the tip of the twisted reamer blade 5 intersect at a substantially right angle.

The apex 41 of the tip shaped part 51 of the twisted reamer blade 5 is located at the tip of the twisted blade 5 for a drill.
protrudes in front of both ends 42, 42 of a flute-shaped cutting edge 44 at the tip thereof, and is adapted to act as a chisel point for the drill.

In addition, the tip of the reamer twisted blade 5 has a shaped part 51.
Both ends 52, 52 (shown in the fifth figure) are located at a position retreating from both ends 42, 42 of the flute-shaped cutting edge 44 of the twisted drill bit 4, that is, from the chamfered part of the twisted drill bit 4, and I am giving Shiro A.

Figure 5 shows the caudal fin-shaped cutting blade 44 and the tip-shaped biting part 5.
In order to clarify the mutual positional relationship between the two parts, the tail fin-shaped cutting blade 44 and the tip-shaped biting part 51 are shown superimposed on the same plane.

It goes without saying that the diameter of the twisted reamer blade 5 is larger than the diameter of the drill twisted blade 4 by the finishing allowance B. The helical drill bit 4 has a flank 43 formed therein.

When drilling with the above-mentioned drill reamer of the present invention, the chisel point 41 and the cutting edge part 5
Tail fin type cutting blade 4 while centering by 1
Drilling starts when both ends 42, 42 of 4 bite, and when the drilling advances by the distance A, the reamer twist blade 5
begins to work, and from then on, drilling is preceded and reaming is performed at the same time.

In other words, the inner surface of the hole is finished at the same time as the hole is drilled, and the machining time is shortened by omitting the pilot hole drilling.

If the drilling position is on a slope as shown by the dashed line l in Figure 5, the end 42 of the tail-fin-shaped cutting edge 44 of the twisted drill bit 4 bites into the higher side of the slope l, but the tail-fin-shaped cut forming the F-shape Due to the biting effect of the blade 44,
Since a reaction force is generated against the lateral cutting resistance acting on the helical drill bit 4, the drill reamer does not tilt. Therefore, the axis of the hole does not shift, resulting in good machining accuracy.

Even if the slope is gentle and the chisel point 41 and the tip-shaped biting part 51 bit into the slope l first, the end 42 of the fluke-shaped cutting edge 44 bites into the slope l in the same way as above, so the drill reamer will not tilt. There is no.

As described above, the drill reamer of the present invention can efficiently perform hole drilling with excellent positional accuracy and hole finish accuracy regardless of the inclination of the surface at the hole drilling position.

Japanese Utility Model Application Publication No. 55-11898 discloses that the cutting edge at the tip of the two-flute twisted blade of a drill is such that the first cutting edge in the center is high, the second cutting edge at both left and right ends are lower than this, and the bottom part in the middle is lower than this. It is known that the cutting edge is formed at its lowest point to create a W-shaped cutting edge, but when grinding that cutting edge, the W-shaped cutting edge makes it difficult for the grindstone to follow.
Grinding is especially difficult at the bottom of the middle blade. It's even more difficult because you have to take second place.

In the present invention, a flute-shaped cutting blade 44 is provided at the tip of the twisted blade 4 for a two-flute drill, and a tip-shaped part 51 is provided at the tip of the twisted blade 5 for a two-flute reamer, which is arranged alternately with the twisted blade 4 for a drill. Since the cutting edge 44 and the chamfered part 51 are arranged to intersect at a substantially right angle, the cutting edge 44 and the chamfered part 51 are simpler than the conventional W-shaped cutting edge; The other side has an F-shape, which makes it easier for the cutting edge grinding wheel to follow and precision grinding.

In addition, in the case of a conventional drill with a W-shaped cutting edge, there are two cutting edges symmetrical to the center of the drill, but in the present invention, there are four cutting edges with the cutting edge 44 and the chamfer 51 spaced approximately 90 degrees apart. Since it is a blade, the chips that come out from cutting with one set of blades are shredded by the other set of blades, which also has the effect of improving the discharge of chips.

As described above, the present invention has the chisel point 41 with the tip-shaped part 51 attached to the twisted reamer blade 5.
In addition, a tail-shaped cutting edge 44 that intersects the tip-shaped biting portion 51 at a substantially right angle is formed on each of the twisted drill blades 4, so that the biting effect of the tail-shaped cutting edge 44 at the start of drilling into the slope can be used. , which prevents the drill reamer from tilting, but as shown in Fig. 6, contrary to the present invention, the chisel point 4 is
1 is formed on the twisted drill bit 4, and the tail-shaped cutting edge 44 is formed on the twisted reaming blade 5, so that the tail-shaped cutting edge 44 is formed at the beginning of drilling on the slope. In order to obtain the biting effect, both ends 42, 42 of the fluke-shaped cutting blade 44, which becomes the biting part of the twisted blade 5 for reaming, are required.
Both ends 5 of the chamfered part 51 of the twisted drill bit 4
Must be submitted before 2.52. Therefore, there is no room for drilling and it is not possible to make holes at all.

Therefore, as shown by chain lines 42', 42', both ends of the flute-shaped cutting edge 44 are connected to both ends 52, 52 of the tip-shaped biting part.
If it is moved back further, a drilling allowance will be created and the hole will open, but the tail-shaped cutting edge will not be able to bite into the slope when drilling begins, and there is a risk that the drill reamer will tilt. Form the tip-shaped chamfered part to form a twisted blade for a reamer, and form the caudal fin-shaped cutting edge to form a twisted blade for a drill. The effects of retracting the cutting edge are significant, including the ease of grinding the cutting edge and the fact that the chips become finer.

[Brief explanation of the drawing]

Figure 1 is a front view of the drill reamer of the present invention, Figure 2 is its top view, Figure 3 is its left side view, and Figure 4 is the first
FIG. 5 is an enlarged front view of the cutting edge, and FIG. 6 is an enlarged sectional view of the cutting edge of a reference example. 1 is the main body, 2 is the shank, 3 is the helical groove, 4 is the twisted blade for the drill, 41 is the chisel point, 42
44 is a flute-shaped cutting blade, 5 is a twisted blade for a reamer, 51 is a chamfered portion, and 52 is both ends of the chamfered portion.

Claims (1)

[Scope of utility model registration request] In a drill reamer in which four twisted grooves are provided and two twisted bits for a drill and two twisted bits for a reamer are arranged alternately, the tip of the cutting edge of the twisted bit for a drill is shaped like a tail, and the twisted tip for a reamer is shaped like a tail. The chamfered part of the reamer is formed into a sword-point shape, and the tail-fin-shaped cutting edge and the sword-point-shaped chamfered part intersect at a substantially right angle. This drill reamer has a shaped cutting edge projected from both ends to serve as a chisel point for a drill, and both ends of a tip shaped part of a twisted reamer edge are set back from both ends of a flute shaped cutting edge of a drill twisted edge.