Cutting tool

Abstract

The invention provides a cutting tool. The cutting tool (10) is provided with a plurality of cutting edge parts (14), and the plurality of cutting edge parts are arranged at intervals in the circumferential direction (D1) of the cutting tool (10). Each of the plurality of cutting edge sections (14) has a cutting edge (20) extending in the radial direction (D2) of the cutting tool (10). The cutting edge (20) has a first partial cutting edge (20A) and a second partial cutting edge (20B) positioned between the first partial cutting edge (20A) and the axial center (AX). The rake angle ([theta] 1) of the first partial cutting edge (20A) is different from the rake angle ([theta] 2) of the second partial cutting edge (20B). Accordingly, the shape and size of cuttings generated during cutting can be controlled.

Description

Technical Field

[0001] The invention relates to a cutting tool. Background Art

[0002] Japanese Patent Application Laid-Open No. 2007-069326 discloses a drill in which the rake angle of the tip of the blade is 0°. Summary of the invention

[0003] In order to remove chips generated during cutting from a workpiece without affecting the machining operation, a cutting tool capable of controlling the shape of the chips while machining is desired.

[0004] One embodiment of the present invention is a cutting tool that rotates relative to a workpiece with an axis as the center, wherein the cutting tool has a plurality of cutting edge portions, the plurality of cutting edge portions are arranged at intervals in the circumferential direction of the cutting tool, the plurality of cutting edge portions respectively have cutting edges extending in the radial direction of the cutting tool, the cutting edge has a first partial cutting edge and a second partial cutting edge located between the first partial cutting edge and the axis, and the rake angle of the first partial cutting edge is different from the rake angle of the second partial cutting edge.

[0005] According to the present invention, it is possible to provide a cutting tool capable of controlling the shape and size of chips generated during cutting.

[0006] The above-mentioned objects, features and advantages will be easily understood through the following description of the embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a figure which shows a cutting tool.

[0008] Figure 2 This is a diagram of the cutting tool blade bottom viewed along the axis.

[0009] Figure 3 This is a diagram focusing on one cutting edge.

[0010] Figure 4 is along Figure 3 Cross-sectional view of IV-IV.

[0011] Figure 5 is along Figure 3 Cross-sectional view of VV.

[0012] Figure 6 It is a diagram showing the state of a part of the cutting edge of the main cutting edge portion when cutting a workpiece.

[0013] Figure 7It is a diagram showing the state of a part of the cutting edge of the minor cutting edge portion when cutting a workpiece. DETAILED DESCRIPTION

[0014] When the chips generated by cutting the object to be processed extend relatively large or long, it is difficult to remove the chips from the object to be processed. In particular, when drilling a hole using a drill or the like, it is difficult to remove the chips from the inside of the hole. In this case, there is a tendency for the chips to entangle with the object to be processed or the cutting tool, etc., resulting in malfunction. The technical purpose of the present invention is to provide a cutting tool that can control the shape of the chips while machining.

[0015] like Figure 1 As shown, the cutting tool 10 is, for example, a drill, but is not limited thereto. The cutting tool 10 is fixed to a spindle of a machine tool, a machining center, or the like. In this case, the cutting tool 10 rotates around the axis AX of the cutting tool 10. In addition, the cutting tool 10 is fixed to a fixture, and the workpiece W (see Figure 6 ) can rotate around the axis AX of the cutting tool 10. The cutting tool 10 has a tool body 12 and a plurality of cutting edge portions 14.

[0016] The tool body 12 is in a rod shape. The axis AX of the tool body 12 is located on the same line as the axis AX of the cutting tool 10. A plurality of cutting edges 14 are formed on the tool body 12. Figure 2 As shown, the plurality of cutting edge portions 14 are arranged at intervals in the circumferential direction D1 of the cutting tool 10. Figure 2 In the embodiment, the number of the cutting edge portions 14 is 4, but the present invention is not limited thereto. The plurality of cutting edge portions 14 have the same structure.

[0017] like Figure 3 As shown, the cutting edge portion 14 has a main edge portion 16 , a secondary edge portion 18 , a cutting edge 20 , an edge direction groove 22 , and a recessed portion 24 .

[0018] The main cutting edge 16 and the auxiliary cutting edge 18 are used for cutting the workpiece. The main cutting edge 16 is arranged in the radial direction D2 (refer to Figure 2 ) is located outside the secondary cutting edge 18. The secondary cutting edge 18 is located between the axis AX of the cutting tool 10 and the main cutting edge 16. A notch is formed in the secondary cutting edge 18. The hardness of the main cutting edge 16 can be equal to that of the secondary cutting edge 18, or can be harder than the secondary cutting edge 18. For example, the main cutting edge 16 is made of diamond, and the secondary cutting edge 18 is made of an alloy such as cemented carbide. The main cutting edge 16 can be brazed to the tool body 12.

[0019] The cutting edge 20 extends in the radial direction D2 of the cutting tool 10. The cutting edge 20 cuts the object by relative rotation of the cutting tool 10 and the workpiece W about the axis AX. The cutting edge 20 includes a partial cutting edge 20A of the main cutting edge portion 16 and a partial cutting edge 20B of the secondary cutting edge portion 18.

[0020] The edge direction groove 22 is formed on the rake face 14F of the cutting edge portion 14. The edge direction groove 22 extends along a portion of the cutting edge 20A. The rake face 14F is a surface through which chips generated by cutting by the cutting edge 20 pass. The edge direction groove 22 is a groove for mainly controlling the shape of chips by curling the chips generated by the cutting edge 20.

[0021] In the present embodiment, as the blade direction groove 22, a blade direction groove 22A, a blade direction groove 22B and a blade direction groove 22C are formed, but it is not limited to this. That is, the blade direction groove 22 can be one or more. In the case where there are multiple blade direction grooves 22, the multiple blade direction grooves 22 are arranged at intervals along the direction of the axis AX of the cutting tool 10. In the present embodiment, the blade direction groove 22A is located at a position closest to the cutting edge 20. The blade direction groove 22B is located at a position farther from the cutting edge 20 than the blade direction groove 22A. The blade direction groove 22C is located at a position farther from the cutting edge 20 than the blade direction groove 22B.

[0022] In addition, when there are multiple blade direction grooves 22, it is the blade direction groove 22A that plays the function of controlling the shape of the chips generated by the partial cutting edge 20A. In this case, the blade direction grooves 22B and the blade direction grooves 22C other than the blade direction grooves 22A among the multiple blade direction grooves 22 do not substantially play the above-mentioned function.

[0023] When the partial cutting edge 20A is worn, the main cutting edge portion 16 is ground from the partial cutting edge 20A to the line Lc1, thereby forming a new partial cutting edge at the position of the line Lc1. In this case, the blade direction groove 22B plays a function of controlling the shape of the chips generated by the partial cutting edge formed at the position of the line Lc1. In addition, when the partial cutting edge formed at the position of the line Lc1 is worn, the main cutting edge portion 16 is ground from the line Lc1 to the line Lc2, thereby forming a new partial cutting edge at the position of the line Lc2. In this case, the blade direction groove 22C plays a function of controlling the shape of the chips generated by the partial cutting edge formed at the position of the line Lc2. That is, when there are multiple blade direction grooves 22, the blade direction grooves 22B and 22C other than the blade direction groove 22A closest to the partial cutting edge 20A are pre-formed in preparation for the formation of a new partial cutting edge.

[0024] like Figure 4As shown, the blade direction groove 22 is surrounded by the first inner side portion 22F1, the second inner side portion 22F2 and the bottom 22BT. The first inner side portion 22F1 and the second inner side portion 22F2 are located between the rake face 14F of the cutting edge portion 14 (main edge portion 16) and the bottom 22BT of the blade direction groove 22. The first inner side portion 22F1 and the second inner side portion 22F2 face each other and extend along a portion of the cutting edge 20A. The bottom 22BT is located between the first inner side portion 22F1 and the second inner side portion 22F2.

[0025] The first inner portion 22F1 is arranged at a position closer to the partial cutting edge 20A than the second inner portion 22F2. The first inner portion 22F1 has an inclined surface IP1, which is inclined in a manner that it becomes lower as it approaches the bottom 22BT. Accordingly, the first inner portion 22F1 can guide the chips generated by the partial cutting edge 20A to the bottom 22BT well. In addition, the inclined surface IP1 can also be curved.

[0026] The second inner portion 22F2 is configured at a position farther from the partial cutting edge 20A than the first inner portion 22F1. The second inner portion 22F2 has an inclined surface IP2, which is inclined in a manner that becomes higher as it moves away from the bottom 22BT. Accordingly, it is easy to curl the chips produced by the partial cutting edge 20A in a manner that is pushed by the inclined surface IP2, and as a result, it is easy to control the shape of the chips. In addition, the inclined surface IP2 can also be curved.

[0027] like Figure 5 As shown, the blade direction groove 22 has a first end 22E1 and a second end 22E2. The first end 22E1 is arranged at a position closer to the axis AX of the cutting tool 10 than the second end 22E2. An inclined surface IP3 is formed between the first end 22E1 and the bottom 22BT, and the inclined surface IP3 is inclined in a manner that it is higher as it moves away from the bottom 22BT. According to this, the movement of the chips generated by the partial cutting edge 20A can be changed, and as a result, the chips are easily divided.

[0028] The second end 22E2 reaches the outer peripheral surface of the main cutting edge 16. The outer peripheral surface of the main cutting edge 16 is coplanar with the surface of the tool body 12, but is not limited to this. Since the second end 22E2 reaches the outer peripheral surface of the main cutting edge 16, the inclined surface IP3 is not formed between the second end 22E2 and the bottom 22BT. In addition, the inclined surface IP3 may be formed between the second end 22E2 and the bottom 22BT. In addition, the inclined surface IP3 may also be curved. In addition, the second end 22E2 may not reach the outer peripheral surface of the main cutting edge 16. In this case, the inclined surface IP3 may be formed at the second end 22E2.

[0029] like Figure 3As shown, the recess 24 is formed on the rake face 14F of the main cutting edge 16. The recess 24 is used to divide the partial cutting edge 20A of the main cutting edge 16. According to this, the recess 24 can cut the chips generated by the partial cutting edge 20A in the direction along the axis AX of the cutting tool 10. As a result, the chips are divided along the radial direction D2 of the cutting tool 10.

[0030] In the present embodiment, two recesses 24, namely recess 24A and recess 24B, are formed, but the present invention is not limited thereto. That is, the recess 24 may be one or more. In the case where there are multiple recesses 24, the multiple recesses 24 are arranged at intervals in the radial direction D2 of the cutting tool 10. In this case, the number of chips divided along the radial direction D2 of the cutting tool 10 can be increased. In addition, the recesses 24 of each of the multiple cutting edge portions 14 arranged at intervals in the circumferential direction D1 of the cutting tool 10 can also be set at positions where the phases are offset from each other. In this case, it is more preferred because it is possible to prevent cutting marks from remaining in the processed hole.

[0031] In this embodiment, the recess 24A is located closest to the axis AX of the cutting tool 10. The recess 24B is located farther from the axis AX of the cutting tool 10 than the recess 24A. The recess 24A and the recess 24B divide the partial cutting edge 20A into a portion S1, a portion S2, and a portion S3.

[0032] One end of the part S1 and one end of the part S2 face each other across the recess 24A. The other end of the part S2 and one end of the part S3 face each other across the recess 24B. The corner of one end of the part S2 is chamfered, and a chamfered portion CN1 is formed on the partial cutting edge 20A. In addition, the corner of one end of the part S3 is chamfered, and a chamfered portion CN2 is formed on the partial cutting edge 20A. By forming the chamfered portions CN1 and CN2, stress concentration on the partial cutting edge 20A can be avoided.

[0033] When a plurality of blade direction grooves 22 are formed, notch portion CO1 and notch portion CO2 may be formed at a location corresponding to chamfer portion CN1. Similarly, notch portion CO3 and notch portion CO4 may be formed at a location corresponding to chamfer portion CN2.

[0034] The notch CO1 is formed on the rake face 14F between the blade direction groove 22A and the blade direction groove 22B. The notch CO1 is formed at a location along the axis AX relative to the chamfered portion CN1. When a new partial cutting edge is formed at the location of the line Lc1, the notch CO1 becomes a chamfered portion.

[0035] The notch CO2 is formed on the rake face 14F between the blade direction groove 22B and the blade direction groove 22C. The notch CO2 is formed at a location along the axis AX relative to the chamfered portion CN1. When a new partial cutting edge is formed at the location of the line Lc2, the notch CO2 becomes a chamfered portion.

[0036] The notch CO3 is formed on the rake face 14F between the blade direction groove 22A and the blade direction groove 22B. The notch CO3 is formed at a location along the axis AX relative to the chamfered portion CN2. When a new partial cutting edge is formed at the location of the line Lc1, the notch CO3 becomes a chamfered portion.

[0037] The notch CO4 is formed on the rake face 14F between the blade direction groove 22B and the blade direction groove 22C. The notch CO4 is formed at a location along the axis AX relative to the chamfered portion CN2. When a new partial cutting edge is formed at the location of the line Lc2, the notch CO4 becomes a chamfered portion.

[0038] The recessed portion 24 may be formed as an axial groove extending along the axis AX of the cutting tool 10. The axial groove intersects the edge direction groove 22. In addition, one end of the axial groove reaches the tip of a portion of the cutting edge 20A.

[0039] In addition, when the recessed portion 24 is formed as an axial groove, the function of dividing the chips generated by the partial cutting edge 20A is exerted by the portion of the axial groove that divides the partial cutting edge 20A. The portion other than this portion does not substantially exert the above-mentioned function. As described above, when the new partial cutting edge is formed at the position of the line Lc1, the portion that divides the newly formed partial cutting edge exerts the above-mentioned function. In addition, when the new partial cutting edge is formed at the position of the line Lc2, the portion that divides the newly formed partial cutting edge exerts the above-mentioned function.

[0040] Figure 6 This is a diagram showing the state of the partial cutting edge 20A of the main cutting edge portion 16 when the workpiece W is cut. Figure 7 This is a diagram showing the state of the partial cutting edge 20B of the minor cutting edge portion 18 when the workpiece W is being cut.

[0041] The rake angle θ1 of the part cutting edge 20A ( Figure 6 ) and the rake angle θ2 of the part cutting edge 20B ( Figure 7 ) are different. Accordingly, the movement of the chips is different between the partial cutting edge 20A and the partial cutting edge 20B. As a result, compared with the case where the movement of the chips is the same between the partial cutting edge 20A and the partial cutting edge 20B, it is easy to split the chips.

[0042] In addition, the rake angle θ1 is an angle formed by an imaginary line L extending in the vertical direction from the surface WF of the object to be processed by cutting and the rake face F2 of the partial cutting edge 20A. In addition, the rake angle θ2 is an angle formed by the imaginary line L and the rake face F4 of the partial cutting edge 20B. The rake face F2 of the partial cutting edge 20A and the rake face F4 of the partial cutting edge 20B are included in the rake face 14F of the cutting edge portion 14.

[0043] In the present embodiment, the angle θ3 formed by the rake face F2 of the partial cutting edge 20A and the flank face F3 of the partial cutting edge 20A is an acute angle. In contrast, the angle θ4 formed by the rake face F4 of the partial cutting edge 20B and the flank face F5 of the partial cutting edge 20B is an obtuse angle. Accordingly, the angle difference between the relative cutting edges of the partial cutting edge 20A and the partial cutting edge 20B becomes larger. As a result, it is easy to split the chips.

[0044] In addition, the angle θ3 of the partial cutting edge 20A is not limited to the case where the angle θ4 of the partial cutting edge 20B is an obtuse angle. For example, both the angle θ3 of the partial cutting edge 20A and the angle θ4 of the partial cutting edge 20B can be acute angles as long as the rake angle θ1 of the partial cutting edge 20A is different from the rake angle θ2 of the partial cutting edge 20B.

[0045] The above-mentioned embodiment also discloses the following supplementary notes.

[0046] (Note 1) The present invention is a cutting tool (10) that rotates relative to a workpiece (W) about an axis (AX), wherein the cutting tool has a plurality of cutting edge portions (14), the plurality of cutting edge portions being arranged at intervals in the circumferential direction (D1) of the cutting tool, the plurality of cutting edge portions each having a cutting edge (20) extending in the radial direction (D2) of the cutting tool, the cutting edge having a first partial cutting edge (20A) and a second partial cutting edge (20B) located between the first partial cutting edge and the axis (AX), the rake angle (θ1) of the first partial cutting edge being different from the rake angle (θ2) of the second partial cutting edge. As a result, the movement of the chips is different between the first partial cutting edge and the second partial cutting edge. As a result, the chips are easily split compared to a case where the movement of the chips is the same between the first partial cutting edge and the second partial cutting edge.

[0047] (Note 2) According to the cutting tool (10) described in Note 1, the angle (θ3) formed by the rake face (F2) of the first cutting edge and the flank face (F3) of the first cutting edge may be an acute angle, and the angle (θ4) formed by the rake face (F4) of the second cutting edge and the flank face (F5) of the second cutting edge may be an obtuse angle. As a result, the angle difference between the relative cutting edges of the first cutting edge and the second cutting edge becomes larger. As a result, the chips are easily split.

[0048] (Note 3) The cutting tool (10) according to Note 1 or 2 may be formed with an edge direction groove (22) extending along the first cutting edge portion on the rake face (14F) of the cutting edge portion, and an inclined surface (IP1) is formed between the rake face of the first cutting edge and the bottom (22BT) of the edge direction groove. As a result, the chips generated by the first cutting edge are easily guided to the edge direction groove. As a result, the chips are easily divided in the edge direction groove.

[0049] (Note 4) According to the cutting tool (10) described in Note 3, an inclined surface (IP3) may be formed between the end (22E1) of the edge direction groove and the bottom of the edge direction groove. This can change the direction of the chips generated by the first cutting edge, and as a result, the chips are easily split.

[0050] (Note 5) According to the cutting tool (10) described in Note 3 or 4, a recess (24) for dividing the first partial cutting edge is formed on the front cutting face of the cutting edge portion, one end of the first portion (S2) of the first partial cutting edge and one end of the second portion (S1) of the first partial cutting edge face each other across the recess, the second portion is located between the first portion and the axis, and a corner portion of one end of the first portion is chamfered to form a chamfered portion (CN1) on the first partial cutting edge. Thus, stress concentration on the first partial cutting edge can be avoided.

[0051] In addition, the present invention is not limited to the above-mentioned technical aspects, and various structures can be adopted within the scope not departing from the gist of the present invention.

Claims

1. A cutting tool (10) which rotates relative to a workpiece (W) about an axis (AX), characterized in that: A plurality of cutting edge portions (14) are provided, wherein the plurality of cutting edge portions are arranged at intervals in the circumferential direction (D1) of the cutting tool. The plurality of cutting edge portions each have a cutting edge (20) extending along a radial direction (D2) of the cutting tool, The cutting edge comprises a first cutting edge portion (20A) and a second cutting edge portion (20B) located between the first cutting edge portion and the axis (AX), The rake angle (θ1) of the first portion of the cutting edge is different from the rake angle (θ2) of the second portion of the cutting edge.

2. The cutting tool according to claim 1, characterized in that The angle (θ3) formed by the rake face (F2) of the first cutting edge and the flank face (F3) of the first cutting edge is an acute angle, An angle (θ4) formed by the rake face (F4) of the second partial cutting edge and the flank face (F5) of the second partial cutting edge is an obtuse angle.

3. The cutting tool according to claim 1 or 2, characterized in that: An edge direction groove (22) extending along the first cutting edge portion is formed on the rake face (14F) of the cutting edge portion. An inclined surface (IP1) is formed between the rake face of the first partial cutting edge and the bottom (22BT) of the edge direction groove.

4. The cutting tool according to claim 3, characterized in that An inclined surface (IP3) is formed between the end portion (22E1) of the blade direction groove and the bottom portion of the blade direction groove.

5. The cutting tool according to claim 1, characterized in that A recess (24) for dividing the first portion of the cutting edge is formed on the rake face of the cutting edge portion. One end of the first portion (S2) of the first cutting edge and one end of the second portion (S1) of the first cutting edge face each other across the recess. The second portion is located between the first portion and the axis. A corner portion at one end of the first portion is chamfered, and a chamfered portion (CN1) is formed on the first partial cutting edge.

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