JPH10263928A - Reamer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce bending moment in machining and enhance working accuracy. SOLUTION: In a reamer 10, three first cutting blades and three second cutting blades are alternately formed on a long cylindrical bar-like member at its circumferential face. Each first cutting blade has a first rough blade part 1b for rough working formed by given length 12 from its tip part and a first finishing blade part 1a following the first rough blade part 1b and formed to a finishing dimension. A radius step d2 is formed between the first rough blade part 1b and the first finishing blade part 1a.

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 pre-machined hole formed by, for example, a drill.

[0002]

2. Description of the Related Art FIGS. 8 and 9 and FIGS. 10 and 11 show the construction of the cutting edge of a conventional reamer. The reamer shown in FIGS. 8 and 9 has a tapered bite angle θ1 formed at the cutting edge. FIG.
Reamers 0 and 11 have a tapered bite angle θ1 at the cutting edge.
Are formed, and a small-diameter blade of length l1 having a step d1 in the radial direction at the tip end of the cutting edge is formed. The step 11 is provided as a re-grinding allowance when the cutting edge is worn and re-grinding. Naturally, the re-grindable length is limited to the re-grinding allowance l1. Japanese Patent Application Laid-Open No. 6-47619 discloses an apparatus in which a step in the radial direction is provided between a cutting edge for roughing and a cutting edge for finishing.

[0003]

Since a reamer is machined following a pre-machined hole with a drill or the like, its straightness is greatly affected by the shape of the pre-machined hole. In particular, in the case of a small-diameter reamer, if there is a misalignment with the pre-machined hole, a bending moment acts on the reamer because the rigidity of the reamer is low even when the guide bush is provided, and the finished machined hole is bent. When the feed amount for the rotation of the reamer is increased, the influence of the bending moment is amplified.

[0004] The bending of the finishing hole has a particularly bad effect when, for example, machining a valve guide hole of an engine. This is because the valve guide hole is functionally processed at the same time as the valve seat portion, so that if a tilt is generated between the valve seat surface and the valve guide hole, the shaft accuracy is reduced and the engine performance is adversely affected. . Also, the bending of the finishing hole causes uneven wear on the reamer, shortening the tool life, and causing breakage of the tool at the time of machining.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a reamer capable of maintaining the accuracy of a finished hole even if a misalignment occurs between the hole and a pre-machined hole. It is.

[0006]

In order to solve the above-mentioned problems and achieve the object, a reamer of the present invention has the following arrangement. That is, in a reamer provided with a plurality of cutting blades in a circumferential direction of a long rod-shaped member, a first reamer formed to a finishing dimension is provided.
A first cutting blade having a blade mold portion, a second blade mold portion formed at a distal end portion from the first blade mold portion and having a smaller diameter than the first blade mold portion, and formed to a finish dimension. A second cutting blade having a third blade mold portion and a fourth blade mold portion formed at a distal end portion of the third blade mold portion and inclined so that its diameter becomes smaller toward the distal end portion. The first cutting blade and the second cutting blade are arranged evenly in the circumferential direction.

[0007]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

[Reamer of First Embodiment] FIG. 1 is a front view showing a configuration of a cutting edge portion of a reamer of a first embodiment according to the present invention. FIG. 2 is a view of the reamer of FIG. 1 as viewed from below.

As shown in FIGS. 1 and 2, a reamer 10 according to a first embodiment has three first cutting blades 1 and 3 alternately arranged on a circumferential surface of a long cylindrical rod-shaped member having a total length of about 280 mm. Two second cutting blades 2 are formed. The first cutting edge 1 has a predetermined length l2 (for example, 20 mm ≦ l2 ≦ 30 mm) from the tip portion.
And a first rough blade portion 1b for rough working formed only
First finishing blade 1 formed to a finishing dimension following coarse blade 1b
a. The radial step d2 between the first rough blade portion 1b and the first finishing blade portion 1a is set to about 10 μm to 50 μm. The end surface of the first rough blade portion 1b has a first end surface portion 1c and a second end surface portion 1d which are inclined at different angles in the axial direction from the front end portion. Further, the side surface of the first rough blade portion 1b has a first side surface portion 1e having a clearance angle θ2 (for example, about 10 °) and a second side surface portion 1f having a clearance angle θ3.

The second cutting blade 2 has a second rough cutting portion 2b for roughing formed from the tip portion thereof by a predetermined length 13 (for example, 10 mm ≦ 13 ≦ 20 mm), and a second rough cutting portion 2b.
And a second finishing blade portion 2a formed in a finishing dimension following the second finishing blade portion 2a. The second coarse blade portion 2b has a bite angle θ5 (for example, inclined such that its diameter becomes smaller toward the tip portion) (for example,
2 ° ≦ θ5 ≦ 10 °). Also, the second rough blade portion 2b
Has a different angle θ from its tip in the axial direction.
6, a first end face 2c and a second end face 2d inclined at θ7. Further, a clearance angle θ4 is provided on the side surface of the second rough blade portion 2b.
(For example, about 20 °).

The tip portion of the second rough blade portion 2b is formed to have a smaller diameter than the first rough blade portion 1b.
Is designed to bite into the pre-machined hole before the second rough blade portion 2b.

The portion 4 sandwiched between the first cutting edge 1 and the second cutting edge is provided with a processed chip discharge port. The final finishing dimension 3 of the work is defined by the rotation locus of the first finishing blade 1a of the first cutting blade 1 and the second finishing blade 2a of the second cutting blade 2.

The length l2 of the first rough blade portion 1b is set to be longer than the length 13 of the second rough blade portion 2b, and as the step d2 of the first rough blade portion 1b is set to be larger, the second rough blade is set. Part 2b
Is set to be large.

[Processing Procedure] When the reamer 10 is moved closer to the front processing hole of the work, first, the first rough blade portion 1 of the first cutting blade 1 is formed.
b bites into the work and cuts the pre-machined hole. When the reamer 10 is continuously pushed forward, the second rough blade portion 2 of the second cutting blade 2 is moved.
The b bites into the work and gradually cuts the pre-processed hole diameter to the finished size diameter. When you push the reamer 10 further,
The second finishing blade portion 2a of the cutting blade 2 bites into the work to cut the pre-processed hole diameter to the finishing size 3, and the first finishing blade portion 1a of the first cutting blade 1 also bites into the work. And is subjected to cutting with a finishing dimension 3 of the pre-machined hole.

FIG. 6 is a diagram showing the distribution of the force acting in the radial direction of the reamer when there is a misalignment between the workpiece and the reamer during processing with the conventional reamer. FIG. 7 is a diagram illustrating a distribution of a force acting in the radial direction of the reamer when there is a misalignment between the workpiece and the reamer during processing with the reamer according to the first embodiment.

6 and 7, the radial force acting on the reamer of the first embodiment (ie, the bending moment acting on the reamer) is clearly reduced from the force acting on the conventional reamer. ing.

Note that the reamer of the first embodiment is, for example,
When used for finishing a valve guide hole of a reciprocating engine for an automobile, the processing accuracy of the valve guide hole is enhanced, which is effective when high accuracy is required between the valve guide hole and another portion such as a valve seat surface.

As described above, according to the reamer of the first embodiment, the first rough blade 1
b is made to act slightly before the second rough blade portion 2b, cutting resistance when the second rough blade portion 2b bites into the work can be reduced, and there is misalignment between the work and the reamer. Even if the first cutting edge 1 and the second cutting edge 2 are arranged alternately, the cutting resistance is balanced by the first cutting edge 1 or the second cutting edge 2. It is well received, and high-precision processing is realized in terms of finished surface roughness, roundness, cylindricity, and the like.

When the second cutting edge has a structure in which the second rough cutting portion 2b is inclined, when the cutting edge is worn and re-grinding, first, the first rough cutting portion of the first cutting blade is used. 1b may be ground to a predetermined length and then reground so that the second rough blade 2b of the second cutting blade is inclined according to the length of the first rough blade 1b reground. The limitation on the length of the re-grinding allowance l1 as shown in the figure is eliminated.

[Reamer of the Second Embodiment] FIG. 3 is a front view showing the configuration of the cutting edge portion of the reamer of the second embodiment according to the present invention. FIG. 4 is a view of the reamer of FIG. 3 as viewed from below.

As shown in FIGS. 3 and 4, the reamer 20 of the second embodiment comprises four first reamers 20 adjacent to the circumferential surface of a long cylindrical rod-shaped member having a total length of about 280 mm. Two second cutting blades 2 are formed between the first cutting blades 1 adjacent to the cutting blade 1 two by two. In other configurations, the same parts as those in the first embodiment are denoted by the same part numbers, and description thereof is omitted.

As described above, according to the reamer of the second embodiment, the first cutting edge is formed more than the second cutting edge. The cutting resistance when the rough blade portion 2b bites the work can be further reduced.

[Reamer Mounting Mechanism for Drilling Machine] Next, a schematic configuration of a reamer mounting mechanism for a drilling machine for using the reamers of the first and second embodiments for finishing will be described. FIG. 5 is a cross-sectional view illustrating a schematic configuration of a reamer attaching mechanism of the drilling machine.

As shown in FIG. 5, a drilling machine reamer mounting mechanism 30 includes a conical block 31 disposed at the tip,
It has a cylindrical block 32 disposed behind the conical block 31 and a cylindrical block 33 disposed so as to fill a hollow portion of the cylindrical block 32, and these blocks 31 to 33 are fixed to each other. Is done.

The conical block 31 has a reamer guide hole 37 at the center thereof for passing the reamers 10 and 20 along the axial direction. The end of the reamers 10 and 20 opposite to the cutting edge is a cylindrical block 33. It is inserted until. The cylindrical block 33 fixes the ends of the reamers 10 and 20 on the side opposite to the cutting edge, and has an oil supply hole 36 at the center thereof along the axial direction.
Is provided. On the outer peripheral portion of the cylindrical block 32,
A bearing 34 is provided, and the conical block 31, the cylindrical block 32, and the cylindrical block 33 are integrally rotated and driven around the reamer guide hole by a driving mechanism (not shown), and along the axial direction in the figure. It is driven back and forth in the left and right direction. At the time of finishing, the reamers 10 and 20 are mounted on the reamer mounting mechanism 30 and driven to rotate at a predetermined number of revolutions around a reamer guide hole, and at a predetermined feed speed in the lateral direction in the figure along the axial direction. It is driven back and forth.

The present invention can be applied to modifications or variations of the above embodiment without departing from the spirit thereof.

For example, it goes without saying that the number and layout of the first and second cutting blades can be increased or decreased as necessary according to the material and shape of the work to be processed.

[0028]

As described above, according to the present invention,
A first blade mold portion having a finish dimension, and a second blade mold portion formed at a distal end portion of the first blade mold portion and inclined so that its diameter decreases toward the distal end portion. A second blade having a cutting blade, a third blade mold portion formed to a finished dimension, and a fourth blade mold portion formed at a tip end portion of the third blade mold portion and having a smaller diameter than the third blade mold portion. By providing the cutting blade, even if a misalignment occurs with the pre-machined hole, the accuracy of the finished machined hole can be maintained.

According to the present invention, the first cutting edge and the second cutting edge are uniformly arranged in the circumferential direction, so that the first cutting edge or the second cutting edge receives cutting resistance in a well-balanced manner. In other words, high-precision processing can be realized with respect to the finished surface roughness, roundness, cylindricity, and the like.

[0030]

[Brief description of the drawings]

FIG. 1 is a front view showing a configuration of a cutting edge portion of a reamer according to a first embodiment of the present invention.

FIG. 2 is a view of the reamer of FIG. 1 as viewed from below.

FIG. 3 is a front view showing a configuration of a cutting edge portion of a reamer according to a second embodiment of the present invention.

FIG. 4 is a view of the reamer of FIG. 3 as viewed from below.

FIG. 5 is a sectional view showing a schematic configuration of a reamer attaching mechanism of the drilling machine.

FIG. 6 is a diagram showing a distribution of a force acting in a radial direction of the reamer when there is a misalignment between the workpiece and the reamer at the time of processing with the conventional reamer.

FIG. 7 is a diagram illustrating a distribution of a force acting in a radial direction of the reamer when there is a misalignment between the workpiece and the reamer during processing with the reamer according to the first embodiment.

FIG. 8 is a diagram showing a cutting edge configuration of a conventional reamer.

FIG. 9 is a diagram showing a cutting edge configuration of a conventional reamer.

FIG. 10 is a diagram showing a cutting edge configuration of a conventional reamer.

FIG. 11 is a view showing a cutting edge configuration of a conventional reamer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... 1st cutting blade 2 ... 2nd cutting blade 3 ... Finishing dimension 2nd cutting blade locus 4 ... Chip discharge path 10, 20 ... Reamer 30 ... Reamer mounting mechanism

Claims (5)

[Claims] 1. A reamer provided with a plurality of cutting blades in a circumferential direction of a long rod-shaped member, a first blade mold portion formed to a finish dimension, and a tip portion formed from the first blade mold portion. A first cutting blade having a second blade mold portion having a smaller diameter than the first blade mold portion; a third blade mold portion formed to a finishing dimension; and a tip portion of the third blade mold portion. And a fourth blade mold portion inclined so that its diameter becomes smaller toward the tip portion.
A reamer, comprising: a cutting blade; wherein the first cutting blade and the second cutting blade are uniformly arranged in a circumferential direction. 2. A tip portion of the fourth blade-shaped portion is provided with the second blade-shaped portion.
The reamer according to claim 1, wherein the reamer is formed to have a smaller diameter than the blade mold portion. 3. The reamer according to claim 1, wherein the second blade mold portion is formed to have a diameter smaller by approximately 10 μm to 50 μm than the first blade mold portion. 4. The reamer according to claim 1, wherein the inclination angle of the fourth blade mold portion is set to approximately 2 ° to 10 °. 5. The reamer according to claim 1, wherein the reamer is used for finishing a valve guide hole of an automobile engine.