Reamer

Abstract

To improve also processed hole accuracy by restraining cut-refuse entanglement and a deficit-breakage of a cutting edge to a reamer.SOLUTION: A reamer having a biting cutting edge 7a, an outer peripheral cutting edge 8a and a scooping surface 9 continuing to these in an axial directional tip part has a plurality of outer peripheral cutting edges 8a in the circumferential direction, and has a tooth space 5, a margin 8b and an outer peripheral flank 8c between a plurality of these outer peripheral cutting edges 8a, and the margin 8b is formed by exceeding a base end side end point part 6 of the tooth space, and a neck 3 is not arranged in a tooth space 5-formed part, and the outer peripheral flank 8c extends up to the base end side end point part 6 of at least the tooth space.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a reamer. [Background technology]

[0002] In a reamer, chips are generated inside the hole, and depending on the discharge conditions of the chips, problems may occur such as the chips damaging the inner wall of the hole, getting entangled in the reamer, or getting stuck in the cutting groove, causing chipping or breakage of the cutting edge. To solve the above problems, a tool with a breaker is known as a conventional technique (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-323541 [Patent Document 2] Special Publication No. 2013-523462 Summary of the Invention [Problem to be solved by the invention]

[0004] The problem to be solved by the present invention is to provide a reamer which reduces the entanglement of chips in the reamer and the chipping and breakage of the cutting edge, and improves the drilled hole accuracy, even without a breaker known in the prior art. [Means for solving the problem]

[0005] The present invention has been made to solve the above-mentioned problems, and provides a reamer having a cutting edge and a peripheral cutting edge at an axial tip and a cutting surface continuous with them, the reamer having a plurality of peripheral cutting edges in a circumferential direction, with a cutting groove, a margin and a peripheral flank surface between the plurality of peripheral cutting edges, the margin being formed beyond the terminal point of the base end of the cutting groove, no neck being provided in the portion where the cutting groove is formed, and the peripheral flank surface extending at least to the terminal point of the base end of the cutting groove.

[0006] Furthermore, the cutting edge may be curved and bulged out toward the tip end.

[0007] Furthermore, the reamer may further have a cutting edge flank that connects the margin and the outer peripheral flank with the end face on the tip side, and forms the cutting edge at the tip end in the rotational direction, and the cutting edge flank may have a shape in which the distance from the reamer axis gradually decreases as it moves rearward in the rotational direction. Effect of the Invention

[0008] The margin (partial cylindrical surface) is formed beyond the end point of the base end of the cutting groove, and the portion where the cutting groove is formed does not have a neck (a narrow portion between the cutting part and the shank part), which prevents chips from wrapping around the reamer body. In addition, the outer peripheral relief surface extends to at least the end point of the base end of the cutting groove, which improves the flow of coolant to the cutting part and ensures an escape route for chips.

[0009] Furthermore, by making the cutting edge curved and bulging toward the tip, the chips can be gradually thinned, further improving chip removal. Also, by making the cutting edge curved, the stress at the time of biting can be dispersed, suppressing chipping and breakage. In the case of a straight cutting edge, the edge wears rapidly in the early stages of processing, so the hole accuracy at the early stages of processing may not be stable, but by making the cutting edge curved, a pseudo-wear state is created, and hole accuracy is stable from the early stages of processing. It also has the effect of suppressing burrs at the entrance and exit of the processed hole.

[0010] Furthermore, because the cutting flank has a shape in which the distance from the reamer axis gradually decreases as it moves rearward in the direction of rotation, the entire cutting flank does not come into contact with the inner wall of the pilot hole when it bites into the pilot hole, preventing an increase in cutting resistance and suppressing problems such as chipping and breakage. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view of a first embodiment of the present invention. [Diagram 2] FIG. [Diagram 3] FIG. [Figure 4] 1A and 1B are partial enlarged views of the first embodiment ((a) is a left side view and (b) is a front view). [Diagram 5] FIG. 2 is a perspective view of a chamfer portion of the first embodiment. [Figure 6] FIG. 1 is a front view of Comparative Example 1 with a chamfered tapered neck. [Figure 7] FIG. 13 is a front view of Comparative Example 2 in which the outer peripheral flank is not extended. [Figure 8] FIG. 4 is a partially enlarged view of the second embodiment of the present invention. [Figure 9] FIG. 11 is a perspective view of a chamfer portion of the second embodiment. [Figure 10] FIG. 13A is a diagram showing a chamfered edge R shape in a conventional configuration, and FIG. [Figure 11] This shows the appearance of the reamer after cutting in Example 2. [Figure 12] FIG. 7 shows the state of the reamer after cutting in the tapered chamfered and necked shape of Comparative Example 1. [Figure 13] 1 is a graph comparing machined hole accuracy between Example 2 and Comparative Example 1. [Figure 14] FIG. 11 is a left side view of the third embodiment of the present invention. [Figure 15] 11A and 11B are partial enlarged views of the third embodiment ((a) is a left side view and (b) is a front view). [Figure 16] FIG. 11 is a perspective view of a breaker portion according to the third embodiment. [Figure 17] 11A and 11B are a left side view and a front view, respectively, of a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS EXAMPLES

[0012] 1 and 2 are a perspective view and a front view of a first embodiment of the present invention. As shown in Fig. 1 and Fig. 2, the reamer of the first embodiment has a cutting edge 2 provided at the axial tip end of a straight rod-shaped reamer body 1, and a shank 4 that is held by chucking provided at the base end. The cutting edge size of this reamer is, for example, 0.3 to 25 mm in diameter.

[0013] At least the cutting edge 2 of the reamer is made of a single material such as cemented carbide, cermet, high speed tool steel, etc. On the other hand, the shank 4 may be made of a material different from that of the cutting edge 2 and may be brazed and joined to the cutting edge 2.

[0014] As shown in FIG. 1, the reamer is used by rotating it clockwise about the reamer axis C when viewed from the base end to the tip end.

[0015] 2 and 3, the cutting portion 2 has a peripheral cutting edge 8a formed along the circumferential direction by a plurality of cutting grooves 5, a margin (partial cylindrical surface) 8b, and a peripheral flank surface 8c. Here, the cutting grooves 5, the margins 8b, and the peripheral cutting edge 8a are formed to extend linearly along the reamer axis C.

[0016] Fig. 6 is a front view of the case with a chamfer taper (straight cutting edge 7a) and neck in Comparative Example 1. As shown in Fig. 6, when the shape has a neck 3, it was discovered that when the neck 3 enters the machined hole, depending on the work material and cutting conditions, chips may wrap around the neck 3 or cutting edge 2.

[0017] In such a case, as shown in Figures 1 and 2 of Example 1, the margin 8b exceeds the end point 6 on the base end side of the cutting groove and is connected directly or via a step to the shank 4 that is gripped by chucking, and the neck 3 shown in Figure 6 is not provided in the portion that overlaps the cutting groove 5, thereby making it possible to prevent chips from wrapping around the reamer body 1.

[0018] Usually, as shown in Comparative Example 2 in Fig. 7, the outer peripheral flank 8c is often extended to the range where the cutting groove 5 is parallel to the reamer axis C (the apex position of the grindstone that processes the cutting groove 5), but in Example 1, it is extended to the end point 6 on the base end side of the cutting groove. Since no neck 3 is provided in the portion of the reamer axis C that overlaps the cutting groove 5, and the outer peripheral flank 8c extends at least to the end point 6 on the base end side of the cutting groove, it is possible to prevent chips from wrapping around the reamer body 1, improve the entry of coolant into the cutting portion 2, and ensure an escape route for the chips.

[0019] The peripheral flank 8c is ground with a grinding wheel R16 as shown in Figure 3. When a φ75 mm grinding wheel is used, for example, a machined surface with a grinding wheel radius R37.5 mm is formed on the shank 4 side as viewed from the left side view. The end of the peripheral flank 8c can be perpendicular to the reamer axis C or angled depending on the angle at which the grinding wheel is swung. As shown in Figure 2, the angle σ between the reamer axis C and the end point of the peripheral flank is 30° to 90° (specifically 60°). EXAMPLES

[0020] The reamer of this embodiment 2 is basically the same as that of the embodiment 1. Therefore, in the following, the differences between the two will be mainly described, and the description of the similarities will be omitted. Also, the same reference numerals will be used to denote the parts corresponding to those of the embodiment 1.

[0021] 4 and 5 are partial enlarged views and a perspective view of the chamfer portion of the first embodiment of the present invention, and as shown in Figs. 8 and 9, the straight chamfer cutting edge 7a formed by the chamfer flank 7b of the first embodiment is replaced with a curved shape bulging toward the tip in the second embodiment. The chamfer flank 7b is a surface that connects the margin 8b and the outer peripheral flank 8c with the tip end face 15 and forms the chamfer cutting edge 7a at the tip in the rotation direction. Here, the curved shape bulging toward the tip includes, for example, a circular arc shape, an elliptical arc shape, or a parabolic shape. Specifically, the chamfer cutting edge 7a of the second embodiment is curved and bulged outward with respect to the reamer axis C more than the straight chamfer cutting edge 7a of the first embodiment.

[0022] By making the cutting edge 7a formed by the cutting clearance 7b curved (circular arc, elliptical arc, parabola, etc.), the thickness of the chips gradually decreases, and in addition to the effect of Example 1, the effect of chip removal can be further improved.

[0023] The cutting edge 7a does not necessarily have to be curved, and a curved cutting edge 7a may be formed following a straight cutting edge 7a. As shown in FIG. 8, for example, the curvature radius of the curved cutting edge 7a following the straight cutting edge angle γ of 45° to 90° is 0.2 to 2.0 mm. In this case, it is preferable to bite into the pilot hole at a curved position. By reducing the curvature radius, the axial distance of the cutting edge 7a is shortened, so that reaming can be performed not only on through holes but also on blind holes and blind holes close to the bottom of the holes.

[0024] In addition, the curved cutting edge 7a is not a so-called chamfered shape obtained by simply rotating a curve around the reamer axis C, but is formed by a cutting edge relief surface 7b that follows the curved cutting edge 7a in the same manner as the straight cutting edge 7a, and the cutting edge relief surface 7b is shaped so that the distance from the reamer axis C gradually decreases as it moves rearward in the direction of rotation.

[0025] FIG. 10(a) is a diagram of the chamfered R shape of the conventional configuration, where r1 is the distance between the tip of the chamfered flank 7b in the rotation direction and the reamer axis C, and r2 is the distance between the rear end of the chamfered flank 7b in the rotation direction and the reamer axis C, and r1=r2. On the other hand, FIG. 10(b) is a diagram of the chamfered R shape of the second embodiment, where r1>r2 is the relationship of the chamfered flank 7b in the second embodiment. Specifically, the chamfered flank 7b in the second embodiment is configured such that the perpendicular line L2 to the straight line L1 connecting the tip of the rotation direction and the reamer axis C and the ridge line L3 on the axial tip side of the chamfered flank 7b form an angle η. This angle η is, for example, 8° to 35°. By making r1>r2 as in the second embodiment, when the chamfered flank 7b bites into the pilot hole, the entire surface of the chamfered flank 7b does not come into contact with the inner wall of the pilot hole, and it is possible to prevent an increase in cutting resistance and suppress problems such as chipping and breakage.

[0026] The reamers of Example 2 and Comparative Example 1 in FIG. 6 were manufactured from cemented carbide with a diameter of 6.0 mm, coated with an AlCr-based coating, and drilled under the conditions shown below.

[0027] Work material: SUS304 Pilot hole drill: Carbide coated drill φ5.9 Rotation speed: 1590 min -1 Cutting speed: 30m / min Feed rate: 0.1mm / rev Feed speed: 159mm / min Hole depth: 18mm (through hole)

[0028] As a result, in Example 2, as shown in Figure 11, no cutting chips were wrapped around the reamer body 1, and 1000 holes could be drilled, and drilling could continue. The drilled hole diameter was also a high-precision hole through which a pin gauge of the same diameter as the actual reamer diameter could pass. In the tapered chamfer (straight chamfer cutting edge 7a) and necked shape of Comparative Example 1 shown in Figure 6, after 100 holes were drilled, chipping occurred on three of six cutting edges, and cutting chips were wrapped around the reamer body 1 as shown in Figure 12, so drilling was discontinued.

[0029] Fig. 13 is a graph comparing the machined hole accuracy between the R chamfer (curved chamfer cutting edge 7a) and neckless shape of Example 2 and the tapered chamfer (straight chamfer cutting edge 7a) and necked shape of Comparative Example 1 shown in Fig. 6. The results are also shown in Table 1 below, but Example 2 has better hole accuracy than Comparative Example 1. The reasons for the longer tool life and improved hole accuracy in Example 2 are that chips do not wrap around the reamer body 1, coolant flows well into the cutting edge 2, the curved cutting edge distributes stress during cutting, preventing chipping and breakage, and chip removal is good.

[0030] [Table 1] EXAMPLES

[0031] The reamer of this embodiment 3 is basically the same as that of the embodiment 1 and the embodiment 2. Therefore, the following description will focus on the differences between the two, and will not repeat the description of the similarities. In addition, the same reference numerals will be used to designate the parts corresponding to those of the embodiment 1.

[0032] FIG. 14 is a left side view of the third embodiment of the present invention, and FIGS. 15 and 16 are partially enlarged views ((a) is a left side view and (b) is a front view) of the third embodiment and a perspective view of a breaker portion.

[0033] As shown in Figures 15 and 16, the cutting face 9 is formed of a recess 10a that is continuous with the cutting edge 7a and the peripheral cutting edge 8a and is recessed in the opposite direction to the rotation direction. The breaker recess 10a is formed by the angle difference between the first rake angle α and the second rake angle β, and the end of the breaker 10a on the rotation shaft side (i.e., the open end on the radially inner side) is straight and is inclined at an inclination angle θ toward the peripheral cutting edge 8a (i.e., away from the reamer axis C) as it moves from the tip side to the base side. This inclination can block the flow of chips, improving the effect of breaking up the chips.

[0034] It is also preferable that the breaker angle 10c, which is the angle between the breaker recess 10a and the breaker edge 10b, be formed in an arc shape, which can reduce curling of chips. EXAMPLES

[0035] Fig. 17 is (a) a left side view and (b) a front view of the fourth embodiment of the present invention. As shown in Fig. 17, a breaker can be added to the shape with the bottom cutting edge formed by the bottom cutting edge second relief 11, bottom cutting edge third relief 12, and gash 13. If there is a bottom cutting edge, it is also effective for blind holes and pocket holes.

[0036] The reamers in the above-described embodiments may be provided with oil holes.

[0037] Although the reamers in the above-mentioned embodiments have six cutting edges, any number of cutting edges may be used. Furthermore, the cutting groove 5 is not limited to a straight groove, but may be a helical groove, and the groove division angle may be either equal or unequal.

[0038] The tip shape of the tool may have a hole center or a convex center required for manufacturing.

[0039] In each of the above-described embodiments, as shown in FIG. 1, the reamer is used by rotating it clockwise around the reamer axis C when viewed from the base end to the tip end. However, the present invention may be configured in a reversed manner, in which case the reamer is used by rotating it counterclockwise around the reamer axis C when viewed from the base end to the tip end.

[0040] Coating the cutting edge 2 of each of the above-mentioned embodiments provides benefits such as increased tool life, increased machining efficiency, improved surface roughness of machined holes, and improved chip removal. Methods for producing coating films include CVD (chemical vapor deposition) and PVD (physical vapor deposition). For example, Ti-based, Cr-based, DLC, diamond, and other raw materials are ionized to form a coating. The type of coating film and thickness are selected according to the application, and properties such as wear resistance, heat resistance, impact resistance, low friction, and adhesion resistance can be obtained.

[0041] Coating improves tool performance, but the cutting edge (e.g., the leading cutting edge 7a or the peripheral cutting edge 8a, etc.) becomes rounded, which reduces the sharpness of the blade. Therefore, coating is applied to the cutting portion 2 before forming the breaker (recess) 10a on the reamer, and then the breaker (recess) 10a is formed after coating the cutting portion 2, which makes it possible to sharpen the edges of the leading cutting edge 7a and the peripheral cutting edge 8a, leading to improved sharpness.

[0042] Therefore, the following method for manufacturing a reamer is also an aspect of the present invention.

[0043] In other words, the manufacturing method of the reamer of the present invention is a method for manufacturing a reamer which has a cutting edge 7a and a peripheral cutting edge 8a at its axial tip and a cutting face 9 continuous with them, the cutting face 9 is formed from a recess continuous with the cutting edge 7a and the peripheral cutting edge 8a and recessed in the opposite direction to the direction of rotation, and has a breaker which breaks chips cut by the cutting edge 7a, and the end of the breaker on the rotation shaft side is inclined toward the peripheral cutting edge 8a as it moves from the tip side to the base end side, and before forming the breaker recess 10a on the cutting face 9, a coating is applied to the cutting edge 7a, the peripheral cutting edge 8a and the cutting face 9, and after the coating is applied, the breaker recess 10a is formed. [Explanation of symbols]

[0044] C Reamer axis 1 Reamer body 2...Blade 3. Neck (the narrow part between the blade and the shank) 4. Shank 5. Groove 6 End point of the cutting groove on the base end side 7a...Cutting edge 7b Chamfered flank 8a: Peripheral cutting edge 8b Margin (partial cylindrical surface) 8c... Peripheral flank 8d Cylindrical surface flush with margin 9. Rake face 10a···Breaker recess 10b Breaker edge 10c···Breaker angle 11... Bottom edge second relief 12. Bottom edge third relief 13. Gash 14 Center hole 15...Tip side end surface 16 Grindstone R L1: Straight line connecting the tip of the rotation direction and the reamer axis C L2 - Perpendicular to L1 L3: Axial tip side ridge of chamfer flank η = angle between L2 and L3 σ: Angle between axis and end of peripheral flank α First rake angle β: Second rake angle γ Chamfer angle (angle between axis and cutting edge) θ: Angle between axis and breaker

Claims

1. A reamer having a leading cutting edge, a peripheral cutting edge, and a rake surface continuous with the leading cutting edge and peripheral cutting edge at an axial tip portion, the reamer having a plurality of the peripheral cutting edges in a circumferential direction, and a cutting groove, a margin, and a peripheral relief surface between the plurality of the peripheral cutting edges, The margin is formed beyond a terminal end portion of the proximal end of the cutting edge, No neck is provided in the portion where the cutting groove is formed, The reamer, wherein the peripheral clearance surface extends at least to a base end terminal point of the cutting groove.

2. The reamer according to claim 1 , wherein the cutting edge is curved and bulges out toward a tip end.

3. The margin and the outer peripheral flank are connected to an end face on the tip side, and the cutting edge is formed at the tip end in the rotation direction.

3. The reamer according to claim 1, wherein the chamfering flank surface is shaped so that the distance from the reamer axis becomes gradually smaller toward the rear in the rotational direction.

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