JPH08155715A - Drill reamer - Google Patents

Abstract

PURPOSE: To highly accurately and swiftly process a hole by forming a cutting edge for drilling at the tip of a shank an a toothed part for reamer on the way to the shank respectively. CONSTITUTION: Because a drill part 3 extends from its tips part to a toothed part 41 of a reamer part 4, reamer finishing is performed by the reamer part 4 in such a state as forming a prepared hole throughly by the drill part 3. Therefore the reamer finishing can be performed under such a condition as preventing the core of the drill reamer from moving. The cutting edge 42 of the reamer part 4 secures superior cutting performance and durability as a rightward helical cutting edge of a helix angle of 10 deg.-45 deg.. Thereby, the hole can be swiftly finished into the one of superior roundness, dimensional accuracy, and surface roughness and life elongation of the drill reamer is attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drill reamer that finishes a reamer while making a prepared hole.

[0002]

2. Description of the Related Art Conventionally, a drill reamer for reaming while making a prepared hole is known as one of tools for making a precise hole in a metal workpiece. This drill reamer is a straight blade reamer having a plurality of cutting blades parallel to the axis, and a cutting blade for forming a prepared hole is formed at the tip of the reamer.
The outer peripheral side of this cutting blade also serves as the blade attachment portion (bite portion) of the reamer. The material of the above drill reamer is the material of the workpiece,
In particular, various selections are made according to hardness, tenacity, etc.
In the case of tenacious materials such as steel, those made of high speed steel (high speed steel) and in the case of aluminum or cast iron those made of cemented carbide are used.

[0003]

Since the drill reamer having the above-mentioned structure is constructed by using only the cutting edge at the tip as the drill portion, it is almost the same as the cutting by the cutting edge, that is, the prepared hole is completely formed. Before that, reaming will be done. As a result, the runout of the drill reamer becomes large, and the roundness and dimensional accuracy of the hole are poor. In addition, there are problems that the machinability is poor, it takes time to drill a hole, and the surface roughness of the hole is rough.

Furthermore, the drill reamer made of HSS applied to a viscous material such as steel has a problem that its life is short, and the drill reamer made of cemented carbide has a problem that it is not suitable for aluminum or cast iron. Although it exhibits good durability, it has a very poor durability for tenacious materials such as steel such as the cutting edge of the reamer being broken in a very short time, making it difficult to use in practice. there were. The present invention has been made in view of the above problems, and an object of the present invention is to provide a drill reamer capable of processing a hole with higher accuracy and speed and having a longer life.
Another object of the present invention is to provide a cemented carbide drill reamer capable of exhibiting practically sufficient durability even for a viscous material such as steel.

[0005]

A drill reamer according to claim 1 for achieving the above object is a right-handed helical flute having a helix angle of 10 ° to 45 ° on a peripheral surface of a shaft having a shank on a rear end side. A plurality of strips are formed, a cutting edge for a drill is formed at the tip of the shaft, and a blade attachment portion for a reamer is formed in the middle of the shaft, and the tip end side of the blade attachment portion for the reamer is
It is characterized in that it is configured as a drill portion having an outer diameter slightly smaller than the finished inner diameter of the hole, and the shank side of the blade attachment portion is configured as a reamer portion.

A drill reamer according to claim 2 is the drill reamer according to claim 1.
In the drill reamer according to the above item, the drill portion and the reamer portion are made of cemented carbide. A drill reamer according to a third aspect is the drill reamer according to the first aspect, wherein the number of blades of the reamer portion is twice or more the number of cutting blades for drilling. The drill reamer according to claim 4 is the drill reamer according to claim 1, wherein the main cutting edge of the cutting edge for drilling is provided with a straight portion on the center side and with a curved recessed portion on the outer peripheral side. is there.

[0007]

According to the drill reamer according to the first aspect, since the drill portion is formed from the tip portion of the shaft to the middle portion thereof, the reaming is completed by the reamer portion while the pilot hole is completely formed by the drill portion. It can be performed. Therefore, reaming can be performed in a state in which the runout of the drill reamer is suppressed. Moreover, since the cutting edge of the reamer portion is a right-handed cutting edge having a helix angle of 10 ° to 45 °, good machinability and durability can be ensured.

According to the drill reamer according to the second aspect, since the drill portion and the reamer portion are made of cemented carbide, good machinability can be exhibited even for sticky materials such as steel and practical use. It is possible to secure sufficient durability. That is, the inventor of the present application, as a result of diligent research, forms the drill portion and the reamer portion with carbide, forms the drill portion from the tip portion of the shaft to the middle portion, and forms the cutting edge of the reamer portion with a twist angle. With a right-handed twisting edge of 10 ° to 45 °, it is possible to secure practically sufficient durability against a tenacious material such as steel which has been difficult to apply in terms of durability. In addition to being able to do so, the inventors obtained the knowledge that the hole can be finished quickly and with high accuracy, and have invented the drill reamer according to claim 2 based on such knowledge.

According to the drill reamer of the third aspect, the number of blades of the reamer portion is twice or more the number of blades of the cutting blade for drilling, so that the roundness of the hole can be further increased. This is because the cross-sectional shape of the hole drilled depends on the number of cutting edges of the drill, for example, if the cutting edge of the drill is two, it is triangular, and if the cutting edge of the drill is four, it is pentagonal. The number of cutting edges of the drill is 1 plus the polygonal shape of the number of corners, so the number of reamer blades should be more than double the number of cutting edges of the drill. This is because the holes formed in the polygon by the drill can be finished in the polygon, that is, in a shape closer to a perfect circle.

According to the drill reamer according to the fourth aspect, the cutting chips are divided at the boundary between the straight portion of the main cutting edge of the cutting blade for drilling and the curved recessed portion to narrow the cutting chips. You can Therefore, as a result of the chips being easily broken, it is possible to prevent the chips from being wound around the drill reamer or being difficult to be discharged from the hole.

[0011]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a front view showing an embodiment of a drill reamer of the present invention. In this drill reamer, a plurality of right-hand twisted flutes 2 are formed on the peripheral surface of the shaft 1 having a straight shank 11 on the rear end side on the front end side, and a predetermined length on the front end side of the shaft 1 is configured as a drill portion 3. A predetermined length on the shank 11 side of the drill portion is configured as the reamer portion 4.

The shaft 1 is made of cemented carbide and has a cutting edge 31 for drilling formed at its tip. Two cutting blades 31 are provided as shown in FIG. 2, and the main cutting blades 31a are symmetrically arranged. Further, a short straight portion 31b is formed on the center side of each main cutting edge 31a, and a curved recessed portion 31c is formed on the outer peripheral side thereof.

The right-hand twist blade groove 2 is formed with four threads at the position corresponding to the land portion of the drill portion 3 in the figure, and the twist angle is set to 25 °, for example.
However, the twist angle of the right twist blade groove 2 is 10 ° to 45 °.
Is appropriately selected within the range. Further, a reamer blade attaching portion 41 is formed at a boundary portion between the drill portion 3 and the reamer portion 4. The blade mounting portion 41 is engraved at a position about ½ to ⅓ of the entire length of the right twisted blade groove 2 from the cutting edge 31 at the tip, and the biting angle thereof is about 20 °. The attached length is set to about 1 mm.

The reamer part 4 has four right-handed twist groove 2
Each of the edge portions is configured as a cutting blade 42, and therefore, the number of blades of the reamer portion 4 is twice the number of blades of the cutting blade 31 for drilling. The number of blades of the reamer portion 4 is set to be 2 times or more, more preferably 2 to 3 times the number of cutting blades 31 for drilling. The outer diameter of the drill part 3 is 0.1 to 0.3 m larger than the finished inner diameter of the hole.
It is set to be smaller by about m. Further, the drill portion 3 and the reamer portion 4 have titanium nitride carbide (TiC).
It is preferable to coat N) in order to prolong the service life.

With the above construction, since the drill portion 3 extends from the tip thereof to the blade mounting portion 41 of the reamer portion 4, the reamer portion 4 is completely formed by the drill portion 3 when the prepared hole is completely formed. Reaming can be done by. Therefore, reaming can be performed in a state in which the runout of the drill reamer is suppressed. Moreover, since the cutting edge 42 of the reamer portion 4 is a right-handed twisting edge having a helix angle of 10 ° to 45 °, good machinability and durability can be secured. Therefore, the hole can be quickly finished with good roundness, dimensional accuracy and surface roughness, and the life of the drill reamer can be extended. In addition, the drill reamer can exhibit practically sufficient durability even for a viscous material such as steel, although the shaft 1 is made of carbide.

Moreover, since the number of blades of the reamer portion 4 is twice or more the number of blades of the cutting blade 31 for drilling, the roundness of the hole can be further increased. In addition, the main cutting edge 31a of the cutting edge 31 for a drill has a straight portion 31b and a curved concave portion 31.
c, the straight portion 31b and the curved recessed portion 31 are provided.
At the boundary with c, the chips can be split into two pieces. Therefore, as a result of the chips being easily broken, the chips can be discharged in a state of being cut into short pieces. Therefore, it is possible to eliminate the defect peculiar to the right twisting blade that the discharge property of the chips is poor and the chips are easily wound around the drill reamer. The drill reamer having the above-mentioned configuration can be easily manufactured by forming the right-handed twisted groove 2 in the land portion of the cemented carbide drill.

[Evaluation test] Using the drill reamer of the present invention, a hole was drilled in the steel and a confirmation test was conducted on its finishing accuracy and durability. Further, as a comparative example, the same test was performed on a conventional HSS straight-blade drill reamer. The specifications and test conditions of the drill reamer of the present invention used in this test are as follows. (1) Specifications of drill reamer Outer diameter 10mm Twist angle 25 ° Drill length 20mm Number of cutting blades for drill 2 pieces Number of reamer blades 4 pieces Material Carbide (TiCN coating) (2) Test condition peripheral speed 38m / Min Feed amount 300mm / min Work material SS41

As a result of the above test, the roundness of the hole machined by the drill reamer of the present invention was 1-2 μm, the grade was H7, and the surface roughness was Rmax 1.5-2.5 μm. Roundness of the hole processed by the drill reamer is 4-6 μm,
The grade was H8 to H9 and the surface roughness was Rmax 6 to 8 μm. Therefore, it was confirmed that the drill reamer of the present invention can finish a hole with extremely high accuracy. Further, the drill reamer of the present invention was able to secure a cutting amount of 70 to 100 m or more, while the drill reamer of the comparative example was 20 m or less. Therefore, it was confirmed that the drill reamer of the present invention can exhibit practically sufficient durability. Furthermore, it was confirmed that the machinability was far better than that of the comparative example.

The drill reamer of the present invention may be formed of high-speed steel, and even in this case, the drill reamer is slightly inferior in machinability and durability as compared with the above-mentioned carbide-made one, but is higher than the conventional high-speed drill reamer. It is possible to drill holes with high precision and speed. The drill reamer of the present invention is not limited to the above embodiment, and for example, more right-handed screw flutes 2 are formed, the shank 11 is a Morse taper shank, and only the drill portion 3 and the reamer portion 4 are provided. Various design changes can be made, such as formation of super hard or high speed steel.

[0020]

As described above, according to the drill reamer according to the first aspect, the reaming can be performed by the reamer portion while the pilot hole is completely formed by the drill portion. Can be suppressed. Also, the twist angle of the cutting edge of the reamer is 10 ° to 4
Since the blade has a right-handed twisting edge of 5 °, good machinability and durability can be secured. Therefore, it is possible to provide a drill reamer capable of quickly forming a highly accurate hole having good roundness, dimensional accuracy, surface roughness, and the like, and having a long life.

According to the drill reamer according to the second aspect, since the drill portion and the reamer portion are made of cemented carbide, the point where the drill portion is formed from the tip portion of the shaft to the middle portion and the cutting edge of the reamer is twisted. Combined with the right-handed helical cutting edge with an angle of 10 ° to 45 °, it can exhibit practically sufficient durability even for tenacious metals such as steel, and can quickly open highly accurate holes. It has a unique effect that it can be formed. According to the drill reamer according to claim 3, since the number of blades of the reamer portion is twice or more the number of blades of the cutting blade for drilling, it is possible to finish the hole with a better roundness. Produce the effect of. Claim 4
According to the drill reamer of the present invention, the cutting chips can be cut into short pieces, so that the cutting chips can be extremely easily processed, which is a unique effect.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a drill reamer of the present invention.

FIG. 2 is a side view of the above embodiment.

[Explanation of symbols]

 1 Axis 2 Right-hand twisted blade groove 3 Drill part 4 Reamer part 31 Cutting edge 41 Blade attachment part

Claims (4)

[Claims] 1. A plurality of right-hand twist blade grooves having a twist angle of 10 ° to 45 ° are formed on the peripheral surface of a shaft having a shank on the rear end side, and a cutting blade for drilling is provided at the tip of the shaft. , A reamer blade attachment part is formed in the middle of the shaft, and the tip side of the reamer blade attachment part is configured as a drill part with an outer diameter slightly smaller than the finished inner diameter of the hole. The drill reamer is characterized in that the shank side of the part is configured as a reamer part. 2. The drill reamer according to claim 1, wherein the drill portion and the reamer portion are made of cemented carbide. 3. The drill reamer according to claim 1, wherein the number of blades of the reamer portion is at least twice the number of cutting blades for drilling. 4. The drill reamer according to claim 1, wherein the main cutting edge of the cutting edge for a drill has a straight portion on the center side and a curved recessed portion on the outer peripheral side.