JPH0760539A - Spiral reamer - Google Patents

Abstract

PURPOSE:To efficiently and accurately perform spread working a hole formed in a metal material by providing a guide part, having a cylindrical margin with a rotary lotus in the axial direction of equal diameter to a maximum diametric part of a point end cutting edge, in a specific width along a shaft of an edge part in the peripheral surface thereof in a point end side of the reamer cutting edge part. CONSTITUTION:In the point end side of a reamer cutting edge part L2, a guide part L4, having a cylindrical margin with a rotary locus in the axial direction of this reamer cutting edge part in diameter equal to a maximum diametric part of a point end cutting edge 16, is provided in a specific width along a shaft of an edge unit 15a. As a result, a rear end of the point end cutting edge 16 is connected to the reamer cutting edge part L2 by the guide part L4. Here is set a maximum diameter d2 of the rotary locus of the point end cutting edge 16 smaller than a maximum diameter d1 of the rotary locus of a reamer cutting edge 19 in diameter by (about 0.004-0.03) d1.

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 boring a hole formed in a metal material, and more particularly to a spiral type reamer capable of carrying out the boring process with higher efficiency and accuracy.

[0002]

2. Description of the Related Art As a conventional spiral reamer, there is, for example, the one disclosed in Japanese Utility Model Publication No. 50-97091. An example of the structure of the above conventional spiral reamer is shown in FIGS. As shown in FIG. 4, this reamer has a shaft portion 1 having a round bar shape, a mounting portion 2 formed on the base end side of the shaft portion 1 and used for fixing to a machine tool, and a columnar shape. The blade portion 3 is fixed to the tip of the portion 1 so as to be coaxial with the shaft portion 1. Here, a material such as steel is used for the shaft portion 1, and a material such as cemented carbide is used for the blade portion 3.

5 and 6 both show the structure of the blade portion 3. FIG. 5 is a front view of the blade portion 3, and FIG. 6 is a sectional view taken along the axis of the blade portion 3. On the outer peripheral portion of the tip of the blade portion 3, a predetermined eating angle θ ₁ (θ ₁ : normally 4
A plurality of (4 in FIG. 5) tip cutting blades 4 that gradually incline toward the base end direction at 5 ° or more) are provided along the circumference of the blade portion 3. Further, a cutout 5 is provided in front of the tip cutting edge 4 in the cutting rotation direction to form a rake face on the tip cutting edge 4 and to improve chip removability. As a result, the tip cutting edge 4 is formed.
Has a structure projecting like an island from the tip surface of the blade 3.

On the other hand, on the outer peripheral surface of the blade portion 3, from the front in the cutting rotation direction of the tip cutting edge 4, a spiral groove 6 forming a spiral in the direction opposite to the cutting rotation direction is provided with a predetermined width margin 7 therebetween. With a twist angle of θ ₂ (θ ₂ : 50 ° to 70 °),
Further, a reamer cutting edge 8 is provided on each of the end edges of the margins 7 on the front end side. On the tip side of the blade portion 3 on the outer peripheral surface, the rotational locus in the axial direction is gradually expanded toward the proximal end side, and the rotational locus in the axial direction is θ.
A reamer cutting edge L ₂ inclined by ₃ (θ ₃ : 30 ′ to 20 °) is provided with a predetermined width along the axis of the blade 3, and the base end side of the reamer cutting edge L ₂ has a back taper. Is the body portion L ₃ provided with.

In the reamer cutting edge portion L ₂ , the reamer cutting edge 8 is provided with an axial clearance angle θ ₄ (θ ₄ : 1 ° to 10 °), while in the body portion L ₃ the reamer cutting edge is provided. No clearance angle is formed at 8, and as a result, a cylindrical margin 7 is formed at the body portion L ₃ . Further, the maximum diameter (D ₂ ) of the rotation trajectory of the tip cutting edge 4 is set to be smaller than the maximum diameter (D ₁ ) of the rotation trajectory of the reamer cutting edge 8 by 0.1 to 0.3 mm in diameter. The radial depth W of the twist groove 6 is constant along the axial direction of the blade 3. Then, the blade portion 3 is fixed to the shaft portion 1 by inserting the tip of the shaft portion 1 into a concave portion 9 provided on the base end surface of the blade portion 3 so as to be coaxial with the axis and brazing the both. Has been done.

[0006]

The above-mentioned conventional spiral reamer has higher accuracy than other conventional straight groove type reamers due to improvement of chip discharge before forming by forming the twist groove 6 and improvement of guideability during reaming. The feature is that it can be perforated. However, due to the structural reasons described below, there are cases where sufficient performance cannot be obtained in terms of manufacturing cost and actual use.

First, the rear end of the tip cutting edge 4 and the reamer cutting edge L
_As shown by reference numeral L ₁ in FIG. 6, ₂ is connected by a guide portion having a margin of a predetermined width, but since the shape of the guide portion L ₁ is not specified, a structure similar to a normal end mill is used. It is reasonable to think that. However, in that case,
Axial relief for guide L ₁ (Note: backing process)
Therefore, there is a drawback that the tip end of the guide portion L ₁ is easily embedded in the hole wall, and the guide property is deteriorated.

Secondly, the rake angle of the reamer cutting edge 8 is specified even though the inclination angle (θ ₃ ) of the reamer cutting edge L ₂ is very small and the hole wall is prone to work hardening. Therefore, the rake angle of the reamer cutting edge 8 is 0, as estimated from the drawing shown in Japanese Utility Model Publication No. 50-97091.
If it is negative or negative, the effect of skiving is difficult to obtain and chatter vibration is likely to occur.

Third, the depth W of the spiral groove 6 in the radial direction.
Is constant along the axial direction of the blade portion 3, and therefore the volume of the twist groove 6 is also constant. As a result, chips that are continuously generated during cutting are not stored in the twist groove 6 and are clogged with chips, or even if cutting oil is supplied, it is difficult to reach the tip of the cutting blade, and the life of the cutting blade is short. There is a drawback that

Fourth, since the blade portion 3 and the shaft portion 1 are integrally joined, a hard coating layer cannot be formed on the surface of the blade portion 3 and, as a result, high-speed processing is impossible and the service life is long. Has the drawback of being shorter. This is because it is necessary to heat the reamer to about 400 ° C. to 550 ° C. in the processing furnace in order to form the coating layer, but the shaft portion 1 is bent due to heating,
This is because the high accuracy before processing cannot be maintained.

Fifth, since the tip cutting edge 4 projects in an island shape from the tip end surface of the blade portion 3, the strength of the tip cutting edge 4 is low, and as a result, ribbon-like chips generated from the tip cutting edge 4 are produced. It is easy to entangle, and the cutting edge may be damaged by the entangled chips especially when processing blind holes. There is also a drawback that the cutting width of the tip cutting edge 4 cannot be increased. Further, since the structure of the tip of the reamer is complicated and the manufacturing is difficult, the manufacturing cost becomes high, and the reamer cannot be supplied at a low cost, which is another problem.

The present invention solves the above-mentioned problems and enables stable and highly accurate hole finishing even with high depth of cut and high feed, and also enables formation of a hard coating layer, and a spiral reamer with high speed and long life. It is possible to provide.

[0013]

According to the present invention, a rod-shaped shaft portion has a cylindrical blade portion coaxial with the shaft portion at the tip thereof, and a radially outer portion is provided at the tip outer peripheral portion of the blade portion. A plurality of tip cutting blades that gradually incline toward the base end direction toward one side are provided along with the circumference of the blade portion, and on the outer peripheral surface of the blade portion, the cutting rotation direction from the front to the cutting rotation direction of the tip cutting blade. In a spiral reamer in which a spiral groove forming a spiral in the opposite direction is provided through a margin of a predetermined width, and a reamer cutting edge is provided at the end edge of the margin, the shaft is provided on the outer peripheral surface of the blade portion. A reamer cutting edge portion whose rotational locus in the direction is gradually expanded toward the base end side is provided with a predetermined width along the axis of the blade portion, and the outer circumference of the blade portion on the tip side of the reamer cutting edge portion. The surface has a rotational locus in the axial direction having the same diameter as the maximum diameter portion of the tip cutting edge. Guide portion having a cylindrical margin,
It is characterized in that it is provided with a predetermined width along the axis of the blade portion.

Here, a positive relief angle may be formed in the axial direction and a positive rake angle may be formed in the radial direction on the reamer cutting edge of the reamer cutting edge portion, and further, the ridge of the spiral groove may be formed. The depth in the radial direction may be gradually increased toward the tip. Furthermore, the blade portion and the shaft portion can be detachably joined by a mechanical joining means.

[0015]

In the spiral reamer of the present invention, a guide portion is provided between the tip cutting blade and the reamer cutting blade portion, which has a cylindrical margin whose axial rotation locus has the same diameter as the maximum diameter portion of the tip cutting blade. However, since the guide portion is provided with a predetermined width along the axis of the blade portion, it is difficult for the guide portion to bite into the hole wall, and the guide effect is improved.

[0016]

Embodiments of the present invention will now be described in more detail with reference to the drawings. Examples of the structure of the spiral reamer according to the present invention are shown in FIGS. In FIG. 1, reference numeral 1 is a cylindrical shaft portion, and the space formed in the central portion is an oil passage 1
It is supposed to be 2. Further, the diameter of the base end side of the shaft portion 11 is expanded,
It is an attachment portion 13 used for fixing to a machine tool. On the other hand, a screw 14 is screwed on the inner peripheral surface of the oil passage 12 located at the tip of the shaft portion 11, and a cylindrical blade portion 15 is provided at the tip of the shaft portion 11 for screwing the base end portion thereof. By being screwed into the shaft 14, it is detachably fixed so as to be coaxial with the shaft 11. Here, a material such as steel is used for the shaft portion 11.

2 and 3 show the structure of the blade portion 15, FIG. 2 is a front view of the blade portion 15, and FIG. 3 is the blade portion 1.
5 is a partial cross-sectional view taken along the axis of FIG. The blade portion 15 is composed of a cylindrical blade body 15a made of cemented carbide or the like, and a joining member 15b inserted from the base end side of the blade body 15a so as to be coaxial with the blade body 15a. And joining member 15
It is integrally joined to b by brazing or the like.

On the outer peripheral portion of the tip of the blade 15a, a predetermined contact angle α ₁ (α ₁ : 15 ° to 75 ° as it goes radially outward).
The tip cutting edge 16 that gradually inclines toward the base end at
A plurality (4 in FIG. 2) are provided along the circumference of 5a.

Further, on the outer peripheral surface of the blade body 15a, from the front in the cutting rotation direction of the tip cutting blade 16, a spiral groove 17 forming a spiral in the direction opposite to the cutting rotation direction is provided through a margin 18 of a predetermined width. Are screwed at a twist angle α ₂ (α _{2 of} 30 ° to 75 °), and reamer cutting blades 19 are provided at the end edges of the margins 18 on the tip side. Furthermore,
On the tip end side of the blade body 15a on the outer peripheral surface, the rotational locus in the axial direction is gradually increased in diameter toward the proximal end side, and the rotational locus in the axial direction is α ₃ (α ₃ : 1 ° 30 ′ to 5 °). ) Is provided with a reamer cutting blade portion L ₂ inclined by a predetermined width along the axis of the blade body 15 a, and the base end side of the reamer cutting blade portion L ₂ is a body portion L ₃ provided with a back taper. ing.

Furthermore, in the case of the reamer of the present invention, the reamer cutting edge 19 of the reamer cutting edge portion L ₂ has a clearance angle α in the axial direction.
₄ (α ₄ : 0 ° 30 'to 5 °) and radial rake angle α
₅ (α ₅ : 2 ° to 10 °) are provided. Further, on the tip side of the reamer cutting blade portion L ₂ , a guide portion L ₄ having a cylindrical margin whose axial rotation locus has the same diameter as the maximum diameter portion of the tip cutting blade 16 is provided on the shaft of the blade body 15a. Along the predetermined width, the rear end of the tip cutting edge 16 and the reamer cutting edge L ₂ are connected by the guide L ₄ . Here, the maximum diameter (D ₂ ) of the rotation trajectory of the tip cutting edge 16 is the reamer cutting edge 1
The diameter is larger than the maximum diameter (D ₁ ) of the rotation locus of 9
04~0.03) · D ₁ as small is set.

Moreover, the groove bottom of the spiral groove 17 is gradually bent toward the tip from the position including at least the reamer cutting edge portion L ₂ toward the tip end with a predetermined inclination angle α _{6 and} , as a result, the twisted portion is twisted. The depth W of the groove 17 in the radial direction gradually increases from the position including at least the reamer cutting edge portion L ₂ toward the tip.

On the other hand, on the base end side of the joining member 15b, there is formed a fitting portion 20 for fitting with the tip end portion of the shaft portion 11 with fitting accuracy IT6 to 7 grade accuracy, and at the center of the fitting portion 20. A screw portion 21 that is screwed with the screw 14 is formed on the portion.
Reference numeral 22 is an oil passage communicating with the oil passage 12 of the shaft portion 11. At the tip of this oil passage 22, an oil hole 23 for discharging cutting oil to the blade portion 15 is directed radially outward. A plurality is formed. Further, the threaded portion 21 is provided on the tip surface of the joining member 15b.
A wrench hole 24 for screwing the screw into the screw 14 is formed.

Then, engage the wrench in the wrench hole 24,
The blade portion 15 is detachably fixed to the shaft portion 11 by screwing the screw portion 21 into the screw 14. Moreover, the tip portion of the shaft portion 11 and the blade portion 15 are doubly restrained at the two locations on the tip end side and the base end side of the screw portion 21 by the fitting portion 20 having the fitting precision IT6 to 7 grade accuracy. Therefore, highly accurate fitting is possible. When it is necessary to form a hard coating layer on the blade portion 15, only the blade portion 15 is heat-treated in a furnace in advance to form the hard coating layer, and then the blade portion 15 is fixed to the shaft portion 11 again. do it.

With the above structure, the following effects can be obtained. First, since the guide portion L ₄ having the cylindrical margin is formed, the guide portion is less likely to bite into the hole wall, the guide effect is improved, and a hole with high roundness can be obtained. Secondly, by forming not only the axial clearance angle α ₄ but also the positive rake angle α ₅ on the reamer cutting edge 19, the sharpness of the reamer cutting edge 19 is improved, and the skiving (canna finishing) action finishes. The surface accuracy is improved and a large chatter suppressing effect is obtained.

Thirdly, by gradually increasing the depth of the spiral groove 17 toward the tip, the volume of the spiral groove 17 gradually increases toward the tip, and as a result, the storage capacity of the chips is improved and the blade portion 15 is formed. The amount of cutting oil discharged to the tip of the blade increases, and the blade portion 15 has a long life. Fourthly, since the blade portion 15 is detachable, the manufacturing cost per reamer can be reduced, and various hard coating layers can be easily formed on the blade portion 15, so that the reamer by heat treatment Deformation is minimized. Therefore, high-speed processing is possible and a long life can be achieved.

Fifth, since there is no protrusion on the tip surface of the blade portion 15, there is no breakage of the blade portion due to entrapment of chips or reduction in strength. Therefore, high-load cutting with high depth of cut and high feed is possible. Moreover, since the structure of the tip portion of the blade portion 15 is simple, there is an effect that it can be manufactured at low cost.

[0027]

[Experimental Examples] Experimental effects will be described below with reference to experimental examples. Using the spiral reamer of the present invention, the prepared hole was bored under the following conditions. (1) Work Material: Alloy Steel SCM440 (HB220)
A hole with a pilot hole with a diameter of 24.5 mm (finish margin 1.15 mm). (2) Reamer: φ25, 65 mm, 4-flute (3) Cutting conditions: Cutting speed = 80.5 m / min (rotation speed 1000 rpm), feed = 400 mm / min
(0.1 mm / blade) Cutting oil = JISW 1st class No. 2 (water-soluble) (4) Results: Finished surface roughness Rmax = 3μ Roundness = 1.3μ Machining length (life) = 200m

From the results of the above experimental example, it is understood that the finished surface roughness and roundness after processing are good, and the processing length is extended as compared with the conventional reamer.

[0029]

As described above, by using the spiral reamer of the present invention, it is possible to carry out the boring process of the hole formed in the metal material with higher efficiency and accuracy.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view showing an example of the shape of a spiral reamer of the present invention.

FIG. 2 is a front view showing an example of the shape of a blade portion of the spiral reamer of the present invention.

FIG. 3 is a partial cross-sectional view taken along the axis of the blade showing an example of the structure of the blade of the spiral reamer of the present invention.

FIG. 4 is a side view showing an example of the shape of a conventional spiral reamer.

FIG. 5 is a front view showing an example of the shape of a blade portion of a conventional spiral reamer.

FIG. 6 is a cross-sectional view taken along the axis of the blade showing an example of the structure of the blade of the conventional spiral reamer.

[Explanation of symbols]

1, 11 Shaft part 2, 13 Mounting part 3, 15 Blade part 4, 16 Tip cutting edge 5 Notch 6, 17 Twist groove 7, 18 Margin 8, 19 Reamer cutting edge 9 Recessed part 12, 22 Oil passage 14 Screw 15a Blade Body 15b Coupling member 20 Fitting part 21 Screw part 23 Oil hole D ₁ Maximum diameter of rotation path of reamer cutting blade D ₂ Maximum diameter of rotation path of tip cutting blade L ₁ , L ₄ Guide part L ₂ Reaming cutting edge part L ₃ Body W Depth of spiral groove in radial direction θ ₁ , α ₁ Eating angle θ ₂ , α ₂ Helix angle θ ₃ , α ₃ Reamer cutting edge inclination angle θ ₄ , α ₄ Reamer cutting edge burr Angle α ₅ Reamer cutting edge rake angle

Claims (4)

[Claims] 1. A rod-shaped shaft portion has a cylindrical blade portion that is coaxial with the shaft portion, and the blade portion has an outer peripheral portion at the distal end thereof that gradually extends in the proximal direction toward the radially outer side. Provided with a plurality of tip cutting blades that incline along the circumference of the blade portion, on the outer peripheral surface of the blade portion, a twist that makes a spiral in a direction opposite to the cutting rotation direction from the front of the cutting rotation direction of the tip cutting blade. In a spiral reamer having a groove provided through a margin of a predetermined width, and a reamer cutting blade provided at each of the end edges of the margin, an axial rotation locus is formed on the outer peripheral surface of the blade portion at the base end side. A reamer cutting blade portion whose diameter is gradually increased toward is provided with a predetermined width along the axis of the blade portion, and the outer peripheral surface of the blade portion on the tip side of the reamer cutting blade portion has an axial direction thereof. A guide having a cylindrical margin whose rotation locus has the same diameter as the maximum diameter portion of the tip cutting edge. The spiral reamer, wherein the edge portion is provided with a predetermined width along the axis of the blade portion. 2. The spiral reamer according to claim 1, wherein the reamer cutting edge of the reamer cutting edge portion has a positive clearance angle in the axial direction and a positive rake angle in the radial direction. . 3. The spiral reamer according to claim 1, wherein the depth of the spiral groove in the radial direction is gradually increased toward the tip. 4. The spiral reamer according to claim 1, wherein the blade portion and the shaft portion are detachably coupled by a mechanical coupling means.