Reamer

Abstract

The reamer is rotatable around a central axis and has a cutting section with an outer cutting edge. The reamer is provided with at least one liquid discharge hole. The at least one liquid discharge hole is configured to remove chips. The cutting section has a slit connected to the outer cutting edge. The cutting section is made of carbide. In a cross section perpendicular to the central axis, if the direction from the central axis toward the cut-off portion of the slit is defined as the first direction, and the direction perpendicular to the first direction is defined as the second direction, the width of the slit in the first direction is 0.2 mm or more and 0.4 mm or less, and the depth of the slit in the second direction is 0.05 mm or more and 0.1 mm or less. In a cross section parallel to the central axis and including the central axis and the outlet of at least one liquid discharge hole, the angle between the direction from the rear end face of the reamer toward the front end face and parallel to the central axis and the liquid discharge direction at the outlet is 10° or more and 45° or less.

Description

Technical Field

[0001] The present disclosure relates to a reamer.

Background Art

[0002] International Publication No. 2021 / 181518 (Patent Document 1) discloses a reamer having an outer peripheral cutting edge.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] The reamer according to the present disclosure is rotatable around a central axis and includes a cutting portion having an outer peripheral cutting edge. The reamer is provided with at least one liquid discharge hole. The at least one liquid discharge hole is configured to be able to remove chips. The cutting portion is provided with a slit continuous with the outer peripheral cutting edge. The cutting portion is made of carbide. In a cross-section perpendicular to the central axis, when the direction from the central axis to the cut-up portion of the slit is defined as the first direction and the direction perpendicular to the first direction is defined as the second direction, the width of the slit in the first direction is 0.2 mm or more and 0.4 mm or less, and the depth of the slit in the second direction is 0.05 mm or more and 0.1 mm or less. In a cross-section parallel to the central axis and including the rear end face and the outlet of the at least one liquid discharge hole of the reamer, the angle formed by the direction from the rear end face to the front end face of the reamer and parallel to the central axis and the liquid discharge direction at the outlet is 10° or more and 45° or less.

Brief Description of the Drawings

[0005] [Figure 1] FIG. 1 is a perspective schematic view showing the configuration of the reamer according to the first embodiment. [Figure 2] FIG. 2 is a plan schematic view showing the configuration of the reamer according to the first embodiment. [Figure 3] Figure 3 is an enlarged schematic diagram of region III in Figure 1. [Figure 4] Figure 4 is a schematic cross-sectional view along the line IV-IV in Figure 2. [Figure 5] Figure 5 is an enlarged schematic diagram of region V in Figure 4. [Figure 6] Figure 6 is a schematic front view showing the configuration of a reamer according to the first embodiment. [Figure 7] Figure 7 is an enlarged schematic diagram of region VII in Figure 6. [Figure 8] Figure 8 is a schematic cross-sectional view along the line VIII-VIII in Figure 6. [Figure 9] Figure 9 is a schematic cross-sectional view along the line IX-IX in Figure 6. [Figure 10] Figure 10 is a schematic front view showing the configuration of a reamer according to the second embodiment. [Figure 11] Figure 11 is a schematic cross-sectional view along the line XI-XI in Figure 10. [Figure 12] Figure 12 is a schematic plan view showing the configuration of a reamer according to the third embodiment. [Figure 13] Figure 13 is a schematic plan view showing the configuration of a reamer according to the fourth embodiment. [Figure 14] Figure 14 is a schematic diagram showing the process of machining a workpiece using a reamer. [Figure 15] Figure 15 shows the relationship between the structure of the sample and the evaluation results. [Figure 16] Figure 16 shows the surface roughness of the inner wall surface of the machined hole. [Modes for carrying out the invention]

[0006] First, embodiments of this disclosure will be listed and described. (1) The reamer according to the present disclosure is rotatable about a central axis and comprises a cutting section having an outer cutting edge. The reamer is provided with at least one liquid discharge hole. The at least one liquid discharge hole is configured to remove chips. The cutting section is provided with a slit connected to the outer cutting edge. The cutting section is made of carbide. In a cross section perpendicular to the central axis, if the direction from the central axis toward the cut-off portion of the slit is defined as the first direction, and the direction perpendicular to the first direction is defined as the second direction, the width of the slit in the first direction is 0.2 mm or more and 0.4 mm or less, and the depth of the slit in the second direction is 0.05 mm or more and 0.1 mm or less. In a cross section parallel to the central axis and including the central axis and the outlet of at least one liquid discharge hole, the angle between the direction from the rear end face of the reamer toward the front end face and parallel to the central axis and the liquid discharge direction at the outlet is 10° or more and 45° or less.

[0007] (2) The entire reamer relating to (1) above may be made of cemented carbide. (3) According to the reamer described in (1) or (2) above, the bottom surface of the slit may be formed by one or more arcs when viewed in the direction along the central axis.

[0008] (4) The reamer according to (1) or (2) above may comprise a main body including a cutting portion and a shank portion connected to the main body. The main body may include a front end face and an interface that is the boundary between the main body and the shank. If the length of the main body in the direction along the central axis is taken as the reference length, the exit may be positioned between a position in the direction along the central axis that is 0.2 times the reference length from the front end face and the position of the interface.

[0009] Next, details of embodiments of the present disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts will be denoted by the same reference numerals, and redundant descriptions will not be repeated.

[0010] <First Embodiment> Figure 1 is a schematic perspective view showing the configuration of a reamer according to the first embodiment. The reamer 100 according to the first embodiment is, for example, a reamer for processing stainless steel material. The reamer 100 is rotatable about a central axis X. As shown in Figure 1, the reamer 100 has a main body portion 110, a shank portion 4, a front end face 101, and a rear end face 102. The shank portion 4 is connected to the main body portion 110. The front end face 101 is formed by the main body portion 110. The rear end face 102 is formed by the shank portion 4. In this specification, the direction from the front end face 101 to the rear end face 102 is also referred to as the rear. Conversely, the direction from the rear end face 102 to the front end face 101 is also referred to as the front.

[0011] Figure 2 is a schematic plan view showing the configuration of a reamer 100 according to the first embodiment. The main body 110 has a cutting section 1, a neck section 2, and a tapered section 3. The cutting section 1 has an outer cutting edge 5. The cutting section 1 is provided with a chip discharge groove 40. The chip discharge groove 40 is, for example, a helical groove. The neck section 2 is connected to the cutting section 1. The neck section 2 is located behind the cutting section 1. The diameter of the neck section 2 is smaller than the diameter of the cutting section 1. The tapered section 3 is connected to the neck section 2. The tapered section 3 is located behind the neck section 2. The diameter of the tapered section 3 increases towards the rear.

[0012] The shank portion 4 is connected to the tapered portion 3. The shank portion 4 is located behind the tapered portion 3. In the direction along the central axis X, the neck portion 2 is located between the cutting portion 1 and the tapered portion 3. In the direction along the central axis X, the tapered portion 3 is located between the neck portion 2 and the shank portion 4. In the direction along the central axis X, the cutting portion 1 is located in the first region R1, the neck portion 2 is located in the second region R2, the tapered portion 3 is located in the third region R3, and the shank portion 4 is located in the fourth region R4. The diameter of the shank portion 4 is larger than the diameter of the neck portion 2.

[0013] In this embodiment, the cutting portion 1 is made of cemented carbide. More specifically, the entire reamer 100 is made of cemented carbide. In another aspect, the cutting portion 1 is made of cemented carbide, and the neck portion 2, the tapered portion 3, and the shank portion 4 may be made of materials other than cemented carbide. In yet another aspect, the cutting portion 1, the neck portion 2, and the tapered portion 3 are made of cemented carbide, and the shank portion 4 may be made of materials other than cemented carbide. In still another aspect, the cutting portion 1 may be detachable from the neck portion 2.

[0014] Figure 3 is an enlarged schematic view of region III in Figure 1. As shown in Figure 3, a slit 30 is provided in the chip discharge groove 40. The slit 30 is continuous with the outer peripheral cutting edge 5. The slit 30 extends along the outer peripheral cutting edge 5. The slit 30 has a bottom surface 31 and a rising portion 32. The bottom surface 31 is continuous with the outer peripheral cutting edge 5. The chip discharge groove 40 has a groove surface 41. The groove surface 41 is continuous with the bottom surface 31.

[0015] The reamer 100 has an outer peripheral surface 20. The outer peripheral cutting edge 5 is formed by the ridge line between the outer peripheral surface 20 and the bottom surface 31 of the slit 30. As shown in Figures 2 and 3, the outer peripheral surface 20 has an outer peripheral cylindrical surface portion 21, a first outer peripheral surface portion 22, and a second outer peripheral surface portion 23. The outer peripheral cylindrical surface portion 21 is continuous with the outer peripheral cutting edge 5. The outer peripheral cylindrical surface portion 21 extends along the outer peripheral cutting edge 5. The first outer peripheral surface portion 22 is continuous with the outer peripheral cylindrical surface portion 21. The outer peripheral cylindrical surface portion 21 is located between the outer peripheral cutting edge 5 and the first outer peripheral surface portion 22. The second outer peripheral surface portion 23 is continuous with the first outer peripheral surface portion 22. The first outer peripheral surface portion 22 is located between the outer peripheral cylindrical surface portion 21 and the second outer peripheral surface portion 23. Note that the outer peripheral surface 20 may not have the second outer peripheral surface portion 23.

[0016] As shown in Figure 2, the reamer 100 has an interface 103. The interface 103 is the boundary between the main body 110 and the shank 4. In the direction along the central axis X, the interface 103 is located between the front end surface 101 and the rear end surface 102. The length of the main body 110 in the direction along the central axis X is the first length L1 (reference length). The length of the shank 4 in the direction along the central axis X is the second length L2. The second length L2 is not particularly limited, but may be shorter than the first length L1. The length of the slit 30 in the direction along the central axis X is the third length L3. The third length L3 is not particularly limited, but may be, for example, 5% or more and 50% or less of the first length L1. The lower limit of the third length L3 is not particularly limited, but may be, for example, 30% or 50% of the length of the first region R1.

[0017] Figure 4 is a schematic cross-sectional view along the line IV-IV in Figure 2. The line IV-IV in Figure 2 is located, for example, 5 mm away from the front end surface 101 along the central axis X. The diagram shown in Figure 4 is a cross-section perpendicular to the central axis X. The rotational direction is the direction in which the reamer rotates, and is also referred to as the forward rotational direction. The rear rotational direction is the direction opposite to the forward rotational direction. As shown in Figure 4, the reamer 100 according to this embodiment is provided with six chip discharge grooves 40. Each of the six chip discharge grooves 40 is provided with a slit 30 connected to the outer cutting edge 5. As shown in Figure 4, in a cross-section perpendicular to the central axis X, the direction from the central axis X toward the cut-off portion 32 of the slit 30 is the first direction A1.

[0018] Figure 5 is an enlarged schematic diagram of region V in Figure 4. As shown in Figure 5, in a cross section perpendicular to the central axis X, the bottom surface 31 of the slit 30 is, for example, arc-shaped. The width of the slit 30 in the first direction A1 is defined as the first width C1. The first width C1 is 0.2 mm or more and 0.4 mm or less. The first width C1 may be 0.22 mm or more and 0.38 mm or less, or 0.24 mm or more and 0.36 mm or less. The first width C1 is the length between the outer cutting edge 5 and the cut-off portion 32 of the slit 30 in the first direction A1. The cut-off portion 32 of the slit 30 is the boundary between the bottom surface 31 and the groove surface 41. The bottom surface 31 is recessed towards the rear in the direction of rotation. Similarly, the groove surface 41 is recessed towards the rear in the direction of rotation.

[0019] As shown in Figure 5, in a cross section perpendicular to the central axis X, the direction perpendicular to the first direction A1 is defined as the second direction A2. The depth of the slit 30 in the second direction A2 is defined as the first depth C2. The first depth C2 is 0.05 mm or more and 0.1 mm or less. The first depth C2 may be 0.055 mm or more and 0.095 mm or less, or 0.06 mm or more and 0.09 mm or less. Note that the first depth C2 is the length between the deepest part of the bottom surface 31 and the cut-off portion 32 in the second direction A2. In the reamer 100 according to this embodiment, in a cross section perpendicular to the central axis X, the outer peripheral cutting edge 5 is located behind the line extending in the first direction A1 in the rotational direction. In another embodiment, in a cross section perpendicular to the central axis X, the outer peripheral cutting edge 5 may be located on the line extending in the first direction A1, or it may be located in front of the line extending in the first direction A1 in the rotational direction.

[0020] Figure 6 is a schematic front view showing the configuration of the reamer 100 according to the first embodiment. The reamer 100 has a forward inclined surface 104. The forward inclined surface 104 is connected to the front end surface 101. The front end surface 101 is perpendicular to the central axis X. The forward inclined surface 104 is inclined rearward with respect to the front end surface 101. As shown in Figure 6, the forward inclined surface 104 is located radially outward from the front end surface 101. The front end surface 101 is connected to the groove surface 41. Viewed along the central axis X, the outer circumferential surface of the tapered portion 3 surrounds the outer circumferential surface 20 of the cutting portion 1.

[0021] Figure 7 is an enlarged schematic diagram of region VII in Figure 6. As shown in Figure 7, when viewed along the central axis X, the width of the slit 30 in the first direction A1 is defined as the second width C3. The second width C3 is 0.2 mm or more and 0.4 mm or less. The second width C3 may be 0.22 mm or more and 0.38 mm or less, or 0.24 mm or more and 0.36 mm or less. The second width C3 may be the same as the first width C1. When viewed along the central axis X, the depth of the slit 30 in the second direction A2 is defined as the second depth C4. The second depth C4 is 0.05 mm or more and 0.1 mm or less. The second depth C4 may be 0.055 mm or more and 0.095 mm or less, or 0.06 mm or more and 0.09 mm or less. The second depth C4 may be the same as the first depth C2.

[0022] As shown in Figure 7, the forward inclined surface 104 is connected to the outer peripheral surface 20, the outer peripheral cutting edge 5, the slit 30, and the groove surface 41. Viewed in the direction along the central axis X, the bottom surface 31 of the slit 30 may be formed by one or more arcs. Specifically, the bottom surface 31 of the slit 30 may be formed by one arc, or by two or more connected arcs. In another embodiment, the bottom surface 31 of the slit 30 may be formed by a combination of arcs and straight lines.

[0023] As shown in Figure 7, the outer circumferential cylindrical surface portion 21 extends in a direction inclined radially inward with respect to the second direction A2, for example. The outer circumferential cylindrical surface portion 21 may also extend along the second direction A2. The first outer circumferential surface portion 22 is located behind the outer circumferential cylindrical surface portion 21 in the rotational direction. The first outer circumferential surface portion 22 is inclined radially inward with respect to the outer circumferential cylindrical surface portion 21. The first outer circumferential surface portion 22 and the second outer circumferential surface portion 23 are relief faces. The relief angle of the second outer circumferential surface portion 23 may be greater than the relief angle of the first outer circumferential surface portion 22. The bottom surface 31 of the slit 30 is a rake face. In the reamer 100 according to this embodiment, when viewed in the direction along the central axis X, the outer circumferential cutting edge 5 is located behind the straight line extending in the first direction A1 in the rotational direction. In another embodiment, when viewed in the direction along the central axis X, the outer peripheral cutting edge 5 may be located on a straight line extending in the first direction A1, or it may be located forward in the rotational direction with respect to the straight line extending in the first direction A1.

[0024] Figure 8 is a schematic cross-sectional view along the line VIII-VIII in Figure 6. The cross-section shown in Figure 8 is parallel to the central axis X and includes the central axis X and the first outlet 6. As shown in Figure 8, the reamer 100 has a flow path 50 through which liquid flows. The flow path 50 has a first flow path section 51, a second flow path section 52, and at least one first liquid discharge hole 53. The first flow path section 51 extends along the central axis X. The first flow path section 51 opens to the rear end face 102. The second flow path section 52 is connected to the first flow path section 51. The diameter of the second flow path section 52 is smaller than the diameter of the first flow path section 51. The second flow path section 52 is located in front of the first flow path section 51. The boundary between the second flow path section 52 and the first flow path section 51 is located at the shank section 4.

[0025] The first liquid discharge hole 53 is connected to the first flow channel 51. The inlet of the first liquid discharge hole 53 is the first inlet 8. The outlet of the first liquid discharge hole 53 is the first outlet 6. The first inlet 8 is the boundary between the first liquid discharge hole 53 and the first flow channel 51. At least a portion of the first liquid discharge hole 53 is located in the shank portion 4. The liquid is introduced into the first flow channel 51, which opens on the rear end face 102 of the reamer 100, and then sent to the first liquid discharge hole 53 through the first inlet 8. The liquid is then discharged to the outside of the reamer 100 through the first outlet 6. In the direction along the central axis X, the first outlet 6 is located behind the boundary between the second flow channel 52 and the first flow channel 51. In the direction along the central axis X, the first inlet 8 is located in front of the boundary between the second flow channel 52 and the first flow channel 51.

[0026] As shown in Figure 8, in a cross-section parallel to the central axis X and including the central axis X and the first outlet 6, the direction from the rear end face 102 of the reamer 100 toward the front end face 101 and parallel to the central axis X is defined as the third direction A3. The direction of liquid discharge at the outlet of the first liquid discharge hole 53 is defined as the fourth direction A4. The fourth direction A4 is the same direction as the direction from the center of the first inlet 8 toward the center of the first outlet 6. The angle between the third direction A3 and the fourth direction A4 is defined as the first angle θ1. The first angle θ1 is between 10° and 45°. The first angle θ1 may be between 12° and 43°, or between 15° and 40°. The liquid discharged from the first liquid discharge hole 53 is sprayed onto the chips. This removes the chips. In other words, the first liquid discharge hole 53 is configured to remove chips. As shown in Figure 6, the first outlet 6 of the first liquid discharge hole 53 is located in the tapered portion 3. At least a portion of the first outlet 6 may be located radially outward from the outer cutting edge 5.

[0027] Figure 9 is a schematic cross-sectional view along the line IX-IX in Figure 6. The cross-section shown in Figure 9 is parallel to the central axis X and includes the central axis X and the second liquid discharge hole 54. As shown in Figure 9, the flow path 50 further has the second liquid discharge hole 54. At least a portion of the second liquid discharge hole 54 is located in the cutting section 1.

[0028] The second liquid discharge hole 54 is connected to the second flow path section 52. The inlet of the second liquid discharge hole 54 is the second inlet 9. The outlet of the second liquid discharge hole 54 is the second outlet 7. The second inlet 9 is the boundary between the second liquid discharge hole 54 and the second flow path section 52. After the liquid is introduced from the first flow path section 51 to the second flow path section 52, it is sent to the second liquid discharge hole 54 through the second inlet 9. The liquid is then discharged to the outside of the reamer 100 through the second outlet 7.

[0029] As shown in Figure 9, the liquid discharge direction at the outlet of the second liquid discharge hole 54 is the fifth direction A5. The fifth direction A5 is the same direction as the direction from the center of the second inlet 9 to the center of the second outlet 7. The angle between the third direction A3 and the fifth direction A5 is the second angle θ2. The second angle θ2 is, for example, between 10° and 80°. The second angle θ2 may be different from the first angle θ1.

[0030] <Second Embodiment> Next, the reamer 100 according to the second embodiment will be described. The reamer 100 according to the second embodiment differs from the reamer 100 according to the first embodiment mainly in that the liquid flow path 50 opens to the front end surface 101, while the other configurations are substantially the same as those of the reamer 100 according to the first embodiment. The following description will focus on the configurations that differ from the reamer 100 according to the first embodiment.

[0031] Figure 10 is a schematic front view showing the configuration of the reamer 100 according to the second embodiment. Figure 11 is a schematic cross-sectional view along the line XI-XI in Figure 10. The reamer 100 according to the second embodiment is a reamer 100 for machining blind holes. As shown in Figures 10 and 11, a second liquid channel 52 opens to the front end face 101. As shown in Figure 10, when viewed along the central axis X, the shape of the outlet of the second channel 52 on the front end face 101 is, for example, circular. As shown in Figure 11, the second channel 52 extends along the central axis X. The second channel 52 is a through hole. After the liquid is introduced from the first channel 51 to the second channel 52, it is discharged to the outside of the reamer 100 through the outlet of the second channel 52 formed on the front end face 101.

[0032] <Third Embodiment> Next, the reamer 100 according to the third embodiment will be described. The reamer 100 according to the third embodiment differs from the reamer 100 according to the first embodiment mainly in the configuration in which the first exit 6 is located at the neck portion 2, but the other configurations are substantially the same as those of the reamer 100 according to the first embodiment. The following description will focus on the configurations that differ from the reamer 100 according to the first embodiment.

[0033] Figure 12 is a schematic plan view showing the configuration of the reamer 100 according to the third embodiment. As shown in Figure 12, in the reamer 100 according to the third embodiment, the first exit 6 is located at the neck portion 2. As shown in Figure 12, when viewed in a direction passing through the center of the first exit 6 and perpendicular to the central axis X, the width of the first exit 6 in the direction parallel to the central axis X may be greater than the width of the first exit 6 in the direction perpendicular to the central axis X. When viewed in a direction perpendicular to the central axis X, the first exit 6 may be elliptical in shape.

[0034] As shown in Figure 12, in the direction along the central axis X, the first exit 6 may be positioned between a position 0.2 times the first length L1 from the front end surface 101 and the position where the boundary surface 103 is located. In the reamer 100 according to this embodiment, in the direction along the central axis X, the center of the first exit 6 is provided at a position 0.8 times the first length L1 from the front end surface 101. In the direction along the central axis X, the center of the first exit 6 may be located behind a position 0.4 times the first length L1 from the front end surface 101, behind a position 0.6 times the first length L1 from the front end surface 101, or behind a position 0.8 times the first length L1 from the front end surface 101.

[0035] <Fourth Embodiment> Next, the reamer 100 according to the fourth embodiment will be described. The reamer 100 according to the fourth embodiment differs from the reamer 100 according to the first embodiment mainly in that the first exit 6 is located in the cutting section 1, while the other configurations are substantially the same as those of the reamer 100 according to the first embodiment. The following description will focus on the configurations that differ from the reamer 100 according to the first embodiment.

[0036] Figure 13 is a schematic plan view showing the configuration of the reamer 100 according to the fourth embodiment. As shown in Figure 13, in the reamer 100 according to the fourth embodiment, the first outlet 6 is located in the cutting section 1. The first outlet 6 is provided, for example, in the chip discharge groove 40. In a direction parallel to the central axis X, the first outlet 6 is located behind the second outlet 7.

[0037] As shown in Figure 13, in the reamer 100 according to this embodiment, the center of the first exit 6 is located at a distance of 0.2 times the first length L1 from the front end face 101 in the direction along the central axis X. In the direction along the central axis X, the center of the first exit 6 may be located axially forward from a distance of 0.4 times the first length L1 from the front end face 101, or axially forward from a distance of 0.3 times the first length L1 from the front end face 101.

[0038] Next, a method for machining a hole formed in a workpiece using a reamer 100 will be described. Figure 14 is a schematic diagram showing the state of machining a workpiece using a reamer 100. As shown in Figure 14, the chips 201 cut by the outer peripheral cutting edge 5 extend spirally backward in the axial direction from the machined hole. Liquid 200 is discharged from the first outlet 6 of the first liquid discharge hole 53 formed in the reamer 100. The liquid 200 is sprayed onto the chips 201. As a result, the chips 201 move radially outward. Consequently, the chips 201 are removed.

[0039] Next, the effects and advantages of the reamer 100 according to this embodiment will be described. The reamer 100 according to this embodiment is rotatable around a central axis X and has a cutting section 1 having an outer peripheral cutting edge 5. The reamer 100 is provided with at least one liquid discharge hole. The at least one liquid discharge hole is configured to remove chips 201. The cutting section 1 is provided with a slit 30 connected to the outer peripheral cutting edge 5. The width of the slit 30 in the first direction A1 is 0.2 mm or more and 0.4 mm or less. This makes it possible to form helical chips 201 with a small curl radius. The depth of the slit 30 in the second direction A2 is 0.05 mm or more and 0.1 mm or less. This makes it possible to form helical chips 201 without damaging the outer peripheral cutting edge 5. Furthermore, the angle between the direction from the rear end face 102 of the reamer 100 toward the front end face 101 and parallel to the central axis X and the liquid discharge direction at the outlet of the at least one liquid discharge hole is 10° or more and 45° or less. This allows the liquid 200 discharged from the liquid outlet to be directed onto the helical chip 201. As a result, it is possible to prevent the helical chip 201 from becoming entangled in the reamer 100.

[0040] According to the reamer 100 of this embodiment, the bottom surface 31 of the slit 30 may be formed by one or more arcs when viewed in the direction along the central axis X. This allows for the smooth discharge of helical chips 201. As a result, it is possible to further prevent helical chips 201 from becoming entangled in the reamer 100.

[0041] According to the reamer 100 of this embodiment, when the length of the main body portion 110 in the direction along the central axis X is taken as the reference length, the outlet of at least one liquid discharge hole may be positioned between a position at a distance of 0.2 times the reference length from the front end surface 101 and a position where the boundary surface 103, which is the boundary between the main body portion 110 and the shank portion 4, is located, in the direction along the central axis X. The chips 201 are discharged axially rearward, and as they move axially rearward, they spread radially outward due to their own weight and centrifugal force. By positioning the outlet of at least one liquid discharge hole axially rearward, the liquid 200 can be directed onto the elongated chips 201. Therefore, the chips 201 can be pushed radially outward more effectively. [Examples]

[0042] (Sample preparation) Samples 1 through 8 were prepared as samples of reamer 100. Samples 1 through 3 are comparative examples. Samples 4 through 8 are examples. Figure 15 shows the relationship between the structure of the samples and the evaluation results. As shown in Figure 15, no liquid discharge hole was formed in sample 1. On the other hand, liquid discharge holes were formed in samples 2 through 8. In sample 2, the depth of the slit 30 was set to more than 0.1 mm. On the other hand, in samples 1 and samples 3 through 8, the depth of the slit 30 was set to 0.05 mm or more and 0.1 mm or less. In sample 3, the width of the slit 30 was set to more than 0.4 mm. On the other hand, in samples 1, 2 and samples 4 through 8, the width of the slit 30 was set to 0.2 mm or more and 0.4 mm or less.

[0043] The width and depth of the slit 30 were measured along the central axis X at positions 1 mm away from the front end surface 101, 2 mm away from the front end surface 101, 3 mm away from the front end surface 101, 4 mm away from the front end surface 101, and 5 mm away from the front end surface 101.

[0044] In sample 5, the position of the liquid discharge hole outlet was set at a distance of 0.2 times the first length L1 from the front end surface 101 in the direction along the central axis X. In sample 6, the position of the liquid discharge hole outlet was set at a distance of 1 time the first length L1 from the front end surface 101 in the direction along the central axis X. On the other hand, in samples 2 through 4, sample 7, and sample 8, the position of the liquid discharge hole outlet was set at a distance of 0.8 times the first length L1 from the front end surface 101 in the direction along the central axis X.

[0045] In sample 7, the discharge angle of the liquid discharge hole was set to 10°. In sample 8, the discharge angle of the liquid discharge hole was set to 45°. On the other hand, in samples 2 through 6, the discharge angle of the liquid discharge hole was set to 15°.

[0046] (Evaluation criteria) Reaming with a 100 reamer was performed on holes formed in the workpiece using samples 1 to 3. The workpiece material was SUS304. The diameter of the 100 reamer was 8.0 mm. The cutting conditions were as follows: The cutting speed (Vc) was 25 m / min. The feed rate (f) was 0.5 mm / revolution. The hole depth (H) was 20 mm. The lubrication method was internal lubrication. The depth of cut (ap) was 0.05 mm / radius. Note that the depth of cut (ap) on the inner surface of the hole is expressed as "mm / radius" for the range from the center of the hole to the inner surface of the hole. In other words, " / " does not mean division. The dimension of ap is not dimensionless but length. According to this notation, if "ap = 0.05 mm / radius", the depth of cut from the inner surface of one hole, passing through the center of the hole and reaching the inner surface of another hole, is 0.10 mm.

[0047] (Evaluation results) Next, we will explain the evaluation results of reaming using the reamer 100 for samples 1 to 8. In Figure 15, regarding the treatment of chips 201, "A" means that the chips 201 did not wrap around the reamer 100, and "B" means that the chips 201 wrapped around the reamer 100. As shown in Figure 15, in sample 1, the chips 201 wrapped around the reamer 100 after machining 47 holes. In sample 3, the chips 201 wrapped around the reamer 100 after machining 2 holes. On the other hand, when reaming was performed using the other reamer 100 samples, the chips 201 did not wrap around the reamer 100.

[0048] Regarding the tool damage in Figure 15, "A" means that the outer cutting edge 5 was not damaged, and "B" means that the outer cutting edge 5 was damaged. As shown in Figure 15, when reaming was performed using reamer 100 of sample 2, the outer cutting edge 5 was damaged after machining 81 holes. On the other hand, when reaming was performed using other reamer 100 samples, the outer cutting edge 5 was not damaged. When reaming was performed using reamer 100 of samples 4 to 8, there was no chip entanglement 201 up to 405 holes machined, and no damage to the outer cutting edge 5 occurred.

[0049] Based on the above results, it was confirmed that by providing a liquid discharge hole and a slit 30 in the reamer 100, setting the width of the slit 30 to 0.2 mm or more and the depth of the slit 30 to 0.05 mm or more and 0.1 mm or less, it is possible to prevent chips 201 from wrapping around the reamer 100 without damaging the outer cutting edge 5. [Examples]

[0050] (Sample preparation) Sample 9 and Sample 6 were prepared as samples of reamer 100. Sample 9 is a comparative example. Sample 6 is an example. In Sample 9, the slit 30 and liquid discharge hole were not formed. On the other hand, the slit 30 and liquid discharge hole were formed in Sample 6. The shape of the slit 30 and the position and discharge angle of the liquid discharge hole in Sample 6 are as shown in Figure 15.

[0051] (Evaluation criteria) Reaming with a 100 tool was performed on holes formed in the workpiece using samples 9 and 6. The workpiece material was SUS304. The diameter of the reamer 100 was 8.0 mm. The cutting conditions were as follows: The cutting speed (Vc) was 25 m / min. The feed rate (f) was 0.5 mm / revolution. The hole depth (H) was 20 mm. The lubrication method was internal lubrication. The depth of cut (ap) was 0.05 mm / radius.

[0052] Next, the surface roughness (arithmetic mean roughness: Ra) of the inner wall surface of the machined hole was measured. The surface roughness measuring instrument used was a Mitutoyo Form Tracer (model number SV-C3100W4). The measurement area was from a position 10 mm away from the entrance surface toward the exit surface of the machined hole to a position 4 mm away toward the entrance surface. The surface roughness (Ra) was measured in accordance with JIS (Japanese Industrial Standards) B0601:2001.

[0053] (Evaluation results) Figure 16 shows the surface roughness of the inner wall surface of the machined hole. When reaming was performed using sample 9, chips 201 wrapped around the reamer 100 after machining one hole. The surface roughness (Ra) of the inner wall surface of the machined hole was 0.31 μm. On the other hand, when reaming was performed using sample 6, no chips 201 wrapped around the reamer 100 after machining 486 holes. The average surface roughness (Ra) of the inner wall surface of the 486 machined holes was 0.14 μm. From these results, it was confirmed that when reaming is performed using the reamer 100 of this embodiment, the surface roughness (Ra) of the inner wall surface of the machined hole can be reduced.

[0054] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the embodiments described herein, and all modifications within the meaning and scope of the claims are intended to be included. It should be understood that at least one configuration or feature described in each embodiment and example can be combined with or modified in various ways in other embodiments and examples. [Explanation of Symbols]

[0055] 1 Cutting section, 2 Neck section, 3 Tapered section, 4 Shank section, 5 Outer circumference cutting edge, 6 First outlet, 7 Second outlet, 8 First inlet, 9 Second inlet, 20 Outer circumference surface, 21 Outer circumference cylindrical surface, 22 First outer circumference surface, 23 Second outer circumference surface, 30 Slit, 31 Bottom surface, 32 Cutting edge, 40 Chip discharge groove, 41 Groove surface, 50 Flow path, 51 First flow path section, 52 Second flow path section, 53 First liquid discharge hole, 54 Second liquid discharge hole, 100 Reamer, 101 Front end surface, 102 Rear end surface, 103 Boundary surface, 104 Forward inclined surface, 110 Main body section, 200 Liquid, 201 Chips, A1 First direction, A2 Second direction, A3 Third direction, A4 Fourth direction, A5 Fifth direction, C1 First width, C2 C3 is the first depth, C4 is the second width, L1 is the first length, L2 is the second length, L3 is the third length, R1 is the first region, R2 is the second region, R3 is the third region, R4 is the fourth region, X is the central axis, θ1 is the first angle, θ2 is the second angle.

Claims

1. A reamer having a cutting section that is rotatable around a central axis and has an outer cutting edge, The reamer is provided with at least one liquid discharge hole, The at least one liquid discharge hole comprises a first liquid discharge hole having a first outlet and a second liquid discharge hole having a second outlet. The first outlet and the second outlet are located on the outer circumferential surface of the reamer, In a direction parallel to the central axis, the first outlet is located behind the second outlet. The cutting portion is provided with a slit connected to the outer cutting edge, The cutting portion is made of cemented carbide. In a cross-section perpendicular to the central axis, if the direction from the central axis toward the cut-off portion of the slit is defined as the first direction, and the direction perpendicular to the first direction is defined as the second direction, then the width of the slit in the first direction is 0.2 mm or more and 0.4 mm or less, and the depth of the slit in the second direction is 0.05 mm or more and 0.1 mm or less. In a cross-section parallel to the central axis and including the central axis and the first outlet, the angle between the direction from the rear end face to the front end face of the reamer and parallel to the central axis and the liquid discharge direction at the first outlet is 10° or more and 45° or less. A reamer in which, when viewed in the direction along the central axis, the bottom surface of the slit is formed by one or more arcs, and the outer cutting edge is located behind the rotational direction with respect to a straight line extending in the first direction.

2. The reamer according to claim 1, wherein the entire reamer is made of carbide.

3. The reamer comprises a main body including the cutting portion and a shank portion connected to the main body, The main body is formed by the cutting portion, the neck portion connected to the cutting portion, and the tapered portion connected to the neck portion and the shank portion, In the direction along the central axis, the neck portion is located behind the cutting portion, the tapered portion is located behind the neck portion, and the shank portion is located behind the tapered portion. The main body portion includes the front end surface and the boundary surface which is the boundary between the main body portion and the shank portion. The reamer according to claim 1 or claim 2, wherein, when the length of the main body in the direction along the central axis is taken as the reference length, the first outlet is located between a position in the direction along the central axis that is 0.2 times the reference length from the front end surface and a position where the boundary surface is located.

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