JPH0985532A - Reamer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reamer capable of easily regrinding without reducing the number of edges of the reamer composed of rough blades and finish blades. SOLUTION: A finish blade 5 is disposed behind a rough edge 4. Thus, the edge groove 3a of the rough edge 4 can be provided larger than the edge groove 3b of the finish edge 5. A chamfer 8a of the rough blade 4 is formed of a clearance surface 9 having a fixed clearance angle, while the chamfer edge 8b of the finish edge 5 is necessarily formed in the same plane as the chamfer edge 8a and further in the position slightly behind the chamfer edge 8a. A margine 6 is left on the outer periphery of the finish edge 5 and the rough edge 4 is adapted to be formed of a clearance surface 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reamer used for finishing a hole.

[0002]

2. Description of the Related Art If a reamer is classified according to the number of blades, it can be divided into a single-blade reamer represented by a general gun reamer and a multi-blade reamer having a plurality of blades. The single-blade reamer is excellent in terms of hole accuracy and hole bending, but is inferior in machining efficiency because it is a single-blade. On the other hand, the multi-blade reamer has 1
Higher efficiency machining is possible than with a single-blade reamer, but the large number of blades complicates the behavior of the cutting edge during cutting, leading to reduced stability of hole accuracy.

One of the multi-blade reamers devised to solve such a problem is one in which rough blades and finishing blades are alternately arranged. For example, Japanese Utility Model Publication No. 61-40433 and Japanese Utility Model Publication No. No. 61-57132 is disclosed. Such a reamer can suppress the cutting allowance of the finishing blade to a preset small value as compared with the above-mentioned reamer, so that the hole accuracy is stable.

[0004]

However, the above-mentioned reamer comprising the combination of the rough blade and the finishing blade has half the apparent number of blades with respect to the rough blade, and the working efficiency does not increase so much. Further, the chamfered blade must be re-ground individually for each cutting edge, and in the technique exemplified in the above publication, the chamfering angle is different between the rough blade and the finishing blade, so that the setup change at the time of regrinding Will be needed. These are factors that cause variations due to regrinding, and the performance maintenance due to regrinding cannot be maintained.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, in which one end of a rod-shaped tool main body has a plurality of rough blades and an outer diameter larger than that of the rough blades. By arranging a finishing blade with a biting blade retracted from the tip,
The present invention relates to a reamer configured to form a blade.

First, the finishing blade is arranged in the vicinity of the rear portion of the rough blade, and the groove of the finishing blade is formed smaller than the groove of the rough blade. Secondly, the flank of the rough blade and the flank of the finishing blade are flush with each other. And thirdly, it is characterized in that the outer circumference of the rough blade is formed as a flank and the outer circumference of the finishing blade is formed as a margin.

[0007]

By arranging the rough blade and the finishing blade close to each other, the total number of blades can be increased. As a result, a large number of blades can be obtained, and it is possible to prevent a reduction in processing efficiency. Moreover, since the cutting allowance that the finishing blade bears can be set to be constant and small, stable hole accuracy is ensured. Actually, since the cutting allowance of the finishing blade is about 0.05 mm to 0.2 mm, even if the finishing blade has a small groove, it does not hinder the chip discharge. Since the rough blade is set so as to bear a larger cutting allowance than the finishing blade, it has a larger blade groove.

The re-grinding of the reamer is performed by driving the flank of the chamfered blade. In the present invention, since the rough blade and the finishing blade are arranged close to each other, the flank of the rough blade may be surface-ground and the flank of the finishing blade may be ground in the same plane. Since the flank surface of the rough blade is ground with a constant clearance angle, the biting blade of the finishing blade is inevitably formed at a position retracted from the biting blade of the rough blade at the tip. Therefore, in the actual drilling, the portion left uncut by the preceding rough blade is left as the cutting allowance for the finishing blade having a large radius, so that a certain cutting allowance is secured and the damage to the finishing blade is made uniform. .

There is a margin on the outer circumference of the finishing blade, which burnishes the wall surface of the hole to be machined and also serves as a guide for the reamer in hole machining. This margin is easily obtained by cylindrical grinding during the reamer manufacturing process. Since the relief is formed on the outer periphery of the rough blade, the cutting resistance can be suppressed.

[0010]

Next, an embodiment of the present invention will be described with reference to the drawings. 1 to 4 exemplify a six-blade cemented carbide gun reamer to which the present invention is applied. As shown in FIG. 1, a round bar-shaped shank 1 is provided with a blade portion 2 at the tip thereof. Round rods made of cemented carbide are joined together. On the outer periphery of the blade portion 2, a blade groove is formed with a twist in the axial direction from the tip, and a partial ridge line thereof serves as a cutting edge.

As shown in FIG. 2 and FIG. 3, the blade groove is composed of two types of blade grooves 3a and 3b of different sizes, each having six blade grooves, a total of twelve blade grooves 3a and 3b in the circumferential direction. They are arranged alternately. The large-sized blade groove 3a is provided with the rough blade 4, and the small-sized blade groove 3b is provided with the finishing blade 5. At this time, two blade grooves 3
The a and the blade groove 3b are arranged close to each other so that the finishing blade 5 is adjacent to the rear portion of the rough blade 4. With such a configuration, it is possible to prevent the number of blades of the rough blade 4 from being reduced to half, which is seen in the conventional rough blade / finish blade combination reamer.

Regarding the outer diameter of the cutting edge, the outer diameter of the finishing blade 5 is made larger than that of the rough blade 4. The difference in outer diameter varies depending on the machining conditions such as the machining allowance of the entire machined hole and the size of the outer diameter of the reamer, but generally the difference in radius is preferably about 0.05 to 0.2 mm. Then, the outer circumference of the finishing blade 5 is provided with a blade groove 3 so that the cylindrical ground surface of the blade portion in the manufacturing process remains with a constant width, and a margin 6 is formed.
a is formed. The margin 6 rubs the inner wall surface of the processed hole for burnishing, and guides the reamer to suppress runout and bending, so that hole processing excellent in hole accuracy, surface roughness, straightness, etc. is performed.

On the other hand, the outer circumference of the rough blade 4 is formed by a flank 7. The flank surface 7 may be a curved surface, but is usually a flat surface that is easy to machine and has a constant clearance angle with respect to the outer peripheral tangent of the rough blade 4. In this case, the flank 7 becomes the first flank. The second flank also serves as the front surface of the blade groove 3b. By forming the clearance angle on the outer periphery of the rough blade 4, the cutting resistance does not increase excessively.

As shown in FIG. 4, biting blades 8a and 8b are formed at the tip corner portion of the blade portion 2. At this time, if the chamfered blade 8b of the finishing blade 5 is at a position retracted from the tip of the chamfered blade 8a of the rough blade 4, only the rough blade 4 is involved in the unrolling process of the hole for the prepared hole, Finishing blade 5
Will not be involved. One of the features of the present invention is that the chamfered blade 8a of the rough blade 4 has a flank 9 with a constant clearance angle. Since the finishing blade 5 is disposed close to the rear portion of the rough blade 4, the chamfered blade 8b of the finishing blade 5 is also ground on the same flank, and inevitably comes to a position retracted from the tip. The attached blade 8b is formed. Normally, re-grinding of the reamer is performed by driving the flank 9 in,
The re-grinding of the gun reamer as described above can be easily performed at the same technical level as that of the conventional 6-blade reamer even if not a reamer manufacturer, and as a result, the re-grinded reamer has less variation in performance. .

In this gun reamer, an oil hole 10 is bored from the rear end of the shank 1 toward the tip thereof, and is branched near the middle of the blade groove 3a so as to communicate with the opening 11 (detailed view is omitted). Exist). Since the flutes 3a and 3b are sized according to the cutting allowances of the rough blade 4 and the finishing blade 5, the chips are not clogged and are cut and forcibly removed by the coolant liquid ejected from the opening 11. It

The biting angle is appropriately selected according to the material of the work material. Further, the present invention is not limited to the above-described embodiment, and is similarly applied to reamers having different blade materials, number of blades, presence / absence of oil holes, twist angles, and the like.

[0017]

As described above, according to the present invention, even with a reamer having a rough blade and a finishing blade, it is possible to prevent the number of blades from being reduced, so that it is possible to achieve a hole with excellent accuracy without lowering machining efficiency. Will be obtained. Further, since each of the rough cutting blade and the finishing cutting blade can be simultaneously obtained by one surface grinding, the grinding work becomes easy, and as a result, the stability of the reamer performance after the re-grinding is secured.

[Brief description of drawings]

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

FIG. 2 is an enlarged side view of FIG.

FIG. 3 is a detailed view in which FIG. 2 is further enlarged.

4 is a configuration diagram of a biting blade portion corresponding to the lower tip corner of FIG. 1. FIG.

[Explanation of symbols]

 3a, 3b Blade groove 4 Rough blade 5 Finishing blade 6 Margin 7 Flank surface 8a, 8b Biting blade 9 Flank surface

Claims (3)

[Claims] 1. A plurality of rough blades 4 at one end of a rod-shaped tool body, and a blade 8 having an outer diameter larger than that of the rough blades 4.
In a reamer in which b is arranged with the finishing blade 5 retracted from the chamfered blade 8a of the rough blade 4 to form the blade portion 2, the finishing blade 5 is arranged close to the rear portion of the rough blade 4. The reamer is characterized in that the blade groove 3b of the finishing blade 5 is formed smaller than the blade groove 3a of the rough blade 4. 2. The reamer according to claim 1, wherein the flank 9 of the chamfered blade 8a of the rough blade 4 and the flank 9 of the chamfered blade 8b of the finishing blade 5 are flush with each other. 3. A flank 7 is formed on the outer periphery of the rough blade 4,
The reamer according to claim 1 or 2, wherein a margin 6 is formed on the outer periphery of the finishing blade 5.