Chamfering tool and chamfering method of workpiece

Abstract

In a chamfering cutter (1), when viewed from the axial direction (X), the cutter (10) is composed of an inner cutter portion (16) extending linearly toward the outer circumference and toward the rear (R2) in the rotation direction (R), an outer cutter portion (17) extending linearly toward the outer circumference and toward the front (R1) in the rotation direction (R) from the radial outside of the inner cutter portion (16), and a curved cutter portion (18) connecting the outer circumferential end of the inner cutter portion (16) and the inner circumferential end of the outer cutter portion (17). During the chamfering operation, the vector (V1) of the cutting force applied from the inner cutter portion (16) to the corner (3) of the workpiece (2) and the vector (V2) of the cutting force applied from the outer cutter portion (17) to the corner (3) of the workpiece (2) are directed toward the center in the width direction of the chamfered surface (5) formed by cutting. Therefore, the generation of Poisson burrs can be suppressed.

Description

Technical Field

[0001] The invention relates to a chamfering cutter installed in a machine tool to chamfer a workpiece and a chamfering method for the workpiece. Background Art

[0002] Patent document 1 describes a chamfering cutter. The chamfering cutter in the document includes a shaft portion connected to the head of a machine tool and a conical cutter portion having a cutter. The shaft portion and the cutter portion are coaxial. The cutter extends along the conical surface of the cutter portion. In addition, when the cutter portion is observed from the axial direction, the cutter extends in a straight line along the radial direction.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2000-326130 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] When the chamfering tool described above is moved in a direction perpendicular to the axis while rotating around the axis to chamfer the corner of the workpiece, there is a problem that Poisson burrs are easily generated.

[0008] The technical problem of the present invention is made in view of the above-mentioned problems, and is to provide a chamfering tool and a chamfering method for a workpiece which can suppress the generation of Poisson burrs.

[0009] Technical solutions adopted to solve technical problems

[0010] In order to solve the above-mentioned technical problems, the present invention is a chamfering tool, which comprises: a knife portion including a cutting knife; and an axis portion coaxial with the knife portion, wherein the cutting knife is arranged along the radial end edge of the knife portion, and rotates around the axis along a specified rotation direction to chamfer the corner of the workpiece, and is characterized in that, when the knife portion is observed from the axis direction, the cutting knife comprises: an inner cutting knife portion, which extends linearly toward the outer peripheral side and toward the rear in the above-mentioned rotation direction; and an outer cutting knife portion, which extends linearly toward the outer peripheral side and toward the front in the above-mentioned rotation direction from the radial outside of the inner cutting knife portion.

[0011] According to the present invention, the cutter includes two cutter parts extending toward the inner circumference and the outer circumference when viewed from the axial direction. With a cutter of this shape, when chamfering the corner of a workpiece, the cutting force applied to the corner of the workpiece from the inner cutter part and the cutting force applied to the corner of the workpiece from the outer cutter part each have a vector toward the center of the width direction of the chamfered surface formed by cutting. In addition, the flow of chips caused by cutting is toward between the inner cutter part and the outer cutter part. As a result, the generation of Poisson burrs at the edge of the chamfered surface formed by cutting can be suppressed.

[0012] In the present invention, the cutter is linearly inclined toward the shaft portion toward the outer periphery when viewed from a direction perpendicular to the axis of the shaft portion. Thus, the chamfered surface formed at the corner of the workpiece by chamfering can be an inclined surface corresponding to the inclination of the cutter.

[0013] In the present invention, the cutter includes a curved cutter portion, and the curved cutter portion is located between the outer peripheral end of the inner cutter portion and the inner peripheral end of the outer cutter portion. Thus, the chamfering blade includes a V-shaped cutter.

[0014] In the present invention, the blade portion includes a chip discharge groove adjacent to the cutter in front of the rotation direction, and the chip discharge groove extends linearly along the axial direction. This makes it easier to manufacture the chamfering blade than when the chip discharge groove is arranged in a spiral around the axis.

[0015] In the present invention, the end portion on the inner peripheral side of the inner cutter portion and the end portion on the outer peripheral side of the outer cutter portion are located at the same angular position around the axis.

[0016] In the present invention, the first angle at which the inner cutter portion is inclined toward the rear relative to the radial direction and the second angle at which the outer cutter portion is inclined toward the front relative to the radial direction are respectively greater than 5° and less than 70°. In this way, the effect of suppressing the generation of Poisson burrs can be found. In addition, it becomes easy to set the cutter on the knife portion.

[0017] In the present invention, the first angle can be made larger than the second angle. In this way, it is easy to suppress the generation of Poisson burrs at the two end edges in the width direction of the chamfered surface. That is, when the chamfering cutter is rotated, the peripheral speed of the outer cutter part located on the outer peripheral side is faster than the peripheral speed of the inner cutter part. Therefore, the cutting force of the outer cutter part is higher than the cutting force of the inner cutter part. Therefore, in the workpiece, compared with the end edge on the other side of the width direction of the chamfered surface after chamfering with the inner cutter part, the end edge on one side of the width direction of the chamfered surface after chamfering with the outer cutter part can suppress the generation of Poisson burrs. In other words, the cutting force of the inner cutter part is lower than the cutting force of the outer cutter part. Therefore, in the workpiece, compared with the end edge on one side of the chamfered surface after chamfering with the outer cutter part, there is a problem that Poisson burrs are easily generated at the end edge on the other side of the chamfered surface after chamfering with the inner cutter part. In order to solve such a problem, if the first angle of the inner cutter portion is made larger than the second angle of the outer cutter portion, the vector of the cutting force applied to the workpiece from the inner cutter portion can be directed toward the center of the width direction of the chamfered surface more than the vector of the cutting force applied to the workpiece from the outer cutter portion. Therefore, the generation of Poisson burrs at the edge of the chamfered surface formed by cutting of the inner cutter portion can be suppressed.

[0018] In the present invention, the difference between the first angle and the second angle can be set to be greater than 2° and less than 10°. In this way, it is easy to set the curved cutter portion located between the inner cutter portion and the outer cutter portion in the radial direction at a position close to an imaginary circle passing through the radial center of the cutter. Here, if the curved cutter portion is set at a position close to the imaginary circle, even if the position of the corner of the workpiece is offset in a direction orthogonal to the moving direction of the chamfering cutter, the inner cutter portion and the outer cutter portion can cut out both end edges in the width direction of the ideal chamfered surface. Therefore, the generation of Poisson burrs can be suppressed.

[0019] In the present invention, when the blade portion is viewed from a direction perpendicular to the axis, the cutter is inclined at 45° relative to the axis. This makes it easier to chamfer the corner of the workpiece.

[0020] In the present invention, the end portion on the outer peripheral side of the inner cutter portion of the cutter can be overlapped with the end portion on the inner peripheral side of the outer cutter portion when viewed from the circumferential direction.

[0021] In the present invention, the cutter includes a curved cutter portion, the curved cutter portion is located between the end of the outer peripheral side of the inner cutter portion and the end of the inner peripheral side of the outer cutter portion in the radial direction, and connects the inner cutter portion to the outer cutter portion, and the cutter includes a curved portion, the curved portion is curved toward the outer peripheral side toward the shaft portion when viewed from a direction orthogonal to the axis of the shaft portion, and the curved cutter portion is provided at the curved portion. In this way, the chamfered surface formed at the corner of the workpiece by chamfering can be set as a curved surface corresponding to the shape of the curved portion of the cutter.

[0022] In the present invention, the cutter includes: a first portion, the first portion extending linearly toward the shaft side and the outer peripheral side when viewed from a direction orthogonal to the axis of the shaft; a curved portion, the curved portion being curved from the end of the first portion on the shaft side; and a second portion, the second portion extending linearly toward the shaft side from the end of the outer peripheral side of the curved portion toward the outer peripheral side. In this way, it is easy to set the curved portion on the cutter. In addition, in this way, it is easy to make the curved portion of the cutter contact with the corner of the work.

[0023] In the present invention, the first angle at which the inner cutter portion is inclined toward the rear relative to the radial direction and the second angle at which the outer cutter portion is inclined toward the front relative to the radial direction can be set to be 5° or more and 85° or less, respectively. In this way, the effect of suppressing the generation of Poisson burrs can be found. In addition, when the cutter includes a curved portion, even when the first angle and the second angle exceed 70°, as long as they are below 85°, it is easy to set the cutter on the knife portion.

[0024] Next, the present invention is a chamfering method, characterized in that the chamfering cutter is caused to contact the corner of the workpiece while rotating around the axis and moving in a direction intersecting the axis.

[0025] According to the chamfering method of the present invention, it is possible to prevent or suppress the generation of Poisson burrs on the chamfered surface formed along the moving direction of the chamfering cutter at the corner of the workpiece.

[0026] Effects of the Invention

[0027] The chamfering blade of the present invention has a substantially V-shaped shape extending forward in the rotation direction when viewed from the axial direction. If the corner of the workpiece is chamfered by a chamfering blade of this shape, Poisson burrs can be suppressed from being generated at the edge of the chamfered surface formed by cutting. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is an appearance diagram of the chamfering cutter of Example 1.

[0029] Figure 2 Observed from the blade side Figure 1 Top view of the chamfering tool.

[0030] Figure 3 Is Figure 1 Illustration of the chamfering action achieved by the chamfering cutter.

[0031] Figure 4 This is a diagram for explaining the positional relationship between a chamfering cutter and a corner of a workpiece.

[0032] Figure 5 This is an explanatory diagram when the positional relationship between the chamfering cutter and the corner of the workpiece is misaligned.

[0033] Figure 6 It is an explanatory diagram of the chamfering operation of the chamfering blade including the arc-shaped cutting blade.

[0034] Figure 7 It is a partial perspective view of the vicinity of the blade portion of the chamfering blade according to a modified example.

[0035] Figure 8 This is an appearance diagram of the chamfering cutter of Example 2.

[0036] Fig. 9 Observed from the blade side Figure 8 Top view of the chamfering tool.

[0037] Fig.10 Is Figure 8 Illustration of the chamfering action achieved by the chamfering cutter. DETAILED DESCRIPTION

[0038] Hereinafter, a chamfering cutter as an embodiment of the present invention will be described with reference to the drawings.

[0039] (Example 1)

[0040] Figure 1 This is an appearance diagram of a chamfering cutter to which the present invention is applied. Figure 2 This is a top view of the chamfering cutter viewed from the blade side. The chamfering cutter 1 of this example is a tool for chamfering a corner 3 of a workpiece 2. The workpiece 2 is, for example, a metal casting. The chamfering cutter 1 is connected to the head of a machine tool (not shown) for use. The chamfering cutter 1 is made of a superhard alloy.

[0041] like Figure 1As shown, the chamfering tool 1 includes: a knife portion 11 including a cutting knife 10; and a shaft portion 12 coaxial with the knife portion 11. The cutting knife 10 is arranged along the radially outer end edge of the knife portion 11. The shaft portion 12 is cylindrical. The shaft portion 12 is connected to the head of the machine tool. The chamfering tool 1 rotates along a prescribed rotation direction R around the axis L of the shaft portion 12 while moving along a direction intersecting the axis L, thereby chamfering the corner 3 of the workpiece 2. In the following, the direction along the axis L of the shaft portion 12 is set as the axial direction X, and the side where the knife portion 11 is located in the axial direction X is set as the front X1, and the side where the shaft portion 12 is located is set as the rear X2.

[0042] The knife portion 11 is continuously arranged at the front X1 of the shaft portion 12. The knife portion 11 includes a flat portion 15 at the center of the front end. In addition, when viewed from a direction perpendicular to the axis L, the radially outer end edge of the knife portion 11 is linearly inclined from the flat portion 15 toward the outer peripheral side toward the shaft portion 12 side. Therefore, when viewed from a direction perpendicular to the axis L, the knife portion 11 includes a trapezoidal side shape that tapers from the front end of the shaft portion 12 toward the front X1 front end. Therefore, when viewed from a direction perpendicular to the axis L, the cutting knife 10 arranged along the radially outer end edge of the knife portion 11 is linearly inclined from the flat portion 15 toward the outer peripheral side toward the shaft portion 12 side. Figure 1 As shown, when viewed from a direction perpendicular to the axis L, the cutter 10 is inclined at 45° relative to the axis L.

[0043] Here, the blade portion 11 includes a chip discharge groove 13 adjacent to the cutter 10. The chip discharge groove 13 is located at a position R1 in front of the cutter 10 in the rotation direction R. The chip discharge groove 13 extends parallel to the axis L on the outer peripheral side of the flat portion 15. The chip discharge groove 13 extends linearly from the front end of the blade portion 11 and reaches the front end portion of the shaft portion 12.

[0044] like Figure 2 As shown, the knife portion 11 includes four cutters 10 at equal angles around the axis L. Therefore, the knife portion 11 includes four chip discharge grooves 13 at equal angles around the axis L. Each chip discharge groove 13 opens radially outward. The opening edge of each chip discharge groove 13 in the knife portion 11 includes a front opening edge portion 13a located in front of the rotation direction R1 and a rear opening edge portion 13b located behind the rotation direction R. Here, the cutter 10 can be set at the rear opening edge portion 13b.

[0045] Each cutter 10 extends from the flat portion 15 toward the outer circumference along the axial direction X. The cutter 10 is composed of an inner cutter portion 16, an outer cutter portion 17, and a curved cutter portion 18, wherein the inner cutter portion 16 extends linearly toward the outer circumference and toward the rear R2 of the rotation direction R when viewed from the axial direction X, the outer cutter portion 17 extends linearly toward the outer circumference and toward the front R1 of the rotation direction R from the radially outer side of the inner cutter portion 16 when viewed from the axial direction X, and the curved cutter portion 18 is located between the outer circumferential end of the inner cutter portion 16 and the inner circumferential end of the outer cutter portion 17 when viewed from the axial direction X. The curved cutter portion 18 is a portion that connects the outer circumferential end of the inner cutter portion 16 and the inner circumferential end of the outer cutter portion 17. The curved cutter portion 18 includes a very small arc. That is, the curved cutter portion 18 is curved. The shape of the cutter 10 when viewed from the axial direction X is substantially V-shaped.

[0046] In this example, the core height of the inner cutter portion 16 is set to an amount corresponding to the dimension H. In other words, when an imaginary plane S parallel to the inner cutter portion 16 and including the axis L is defined, the inner cutter portion 16 is located at a position corresponding to the amount of the dimension H from the rear R2 in the rotation direction R of the inner cutter portion 16 toward the front R1 in the rotation direction R.

[0047] In addition, in this example, the end 16a of the inner peripheral side of the inner cutter portion 16 and the end 17a of the outer peripheral side of the outer cutter portion 17 are at the same angular position around the axis L. The first angle θ1 at which the inner cutter portion 16 is inclined relative to the radial rearward X2 and the second angle θ2 at which the outer cutter portion 17 is inclined relative to the radial forward X1 are respectively greater than 5° and less than 70°. More preferably, the first angle θ1 and the second angle θ2 are greater than 25° and less than 45°. In addition, preferably, the first angle θ1 at which the inner cutter portion 16 is inclined is greater than the second angle θ2 at which the outer cutter portion 17 is inclined. In this example, the first angle θ1 is 35.45° and the second angle θ2 is 30°. The difference between the first angle θ1 and the second angle θ2 is 5.45°. In addition, the bending point 18a of the curved shape of the curved cutter portion 18 is located slightly closer to the inner peripheral side than the imaginary circle C passing through the center 10a of the cutter in the radial direction.

[0048] In the blade portion 11, the front opening edge portion 13a of the chip discharge groove 13 facing the cutter 10 extends linearly from the flat portion 15 toward the outer circumference and toward the front R1 in the rotation direction R when viewed from the axial direction X. Figure 1 As shown, the front opening edge portion 13a of the chip discharge groove 13 opposite to the cutter 10 extends linearly along the axial direction X. In the inner wall surface of the chip discharge groove 13, the inner wall surface portion 13c opposite to the cutter 10 is flat (refer to Figure 3 ).

[0049] (Chamfering action)

[0050] Figure 3 This is an explanatory diagram of a chamfering operation for chamfering the corner portion 3 of the workpiece 2 . Figure 4 It is an explanatory diagram of the positional relationship between the chamfering cutter 1 and the corner portion 3 of the workpiece 2 during the chamfering operation. Figure 4 (a) is a side view when the chamfering cutter 1 and the workpiece 2 are viewed from a direction perpendicular to the axis L. Figure 4 (b) is an explanatory diagram when the contact portion between the chamfering cutter 1 and the workpiece 2 is viewed from the axial direction X. Figure 5 This is an explanatory diagram when the positional relationship between the chamfering cutter 1 and the corner portion 3 of the workpiece 2 is misaligned. Figure 5 (a) is a side view of the chamfering cutter 1 and the workpiece 2 when viewed from a direction perpendicular to the axis L. Figure 5 (b) is an explanatory diagram when the contact portion between the chamfering cutter 1 and the workpiece 2 is viewed from the axial direction X. Figure 6 It is an explanatory diagram of the chamfering operation of the chamfering blade of the comparative example including the arc-shaped cutting blade.

[0051] During chamfering, the chamfering cutter 1 is connected to a machine tool and rotated about an axis L in a predetermined rotation direction R. The chamfering cutter 1 is moved in a moving direction M orthogonal to the axis L with the blade portion 11 in contact with the corner 3 of the workpiece 2 to form a chamfered surface 5 .

[0052] When the blade 11 is brought into contact with the corner 3 of the workpiece 2, first, an ideal chamfered surface 5 is set. Figure 4 As shown in (a), the chamfering cutter 1 is arranged so that the radial center 10a of the cutter 10 is located at the center of the width direction of the ideal chamfered surface 5. Then, in a state where the center of the width direction of the ideal chamfered surface 5 coincides with the radial center 10a of the cutter 10, the chamfering cutter 1 is moved along the moving direction M. As a result, a chamfered surface 5 is formed at the corner 3 of the workpiece 2, and the chamfered surface 5 is inclined at the same angle as the angle at which the cutter 10 is inclined relative to the axis L and extends along the moving direction M.

[0053] Here, if Figure 4As shown in (b), in the chamfering cutter 1 of this example, the cutter 10 is composed of an inner cutter portion 16, an outer cutter portion 17 and a curved cutter portion 18. The inner cutter portion 16 extends linearly toward the outer circumference and toward the rear R2 in the rotation direction R when viewed from the axial direction X, and the outer cutter portion 17 extends linearly toward the outer circumference and toward the front R1 in the rotation direction R from the radially outer side of the inner cutter portion 16 when viewed from the axial direction X. The curved cutter portion 18 connects the outer circumferential end of the inner cutter portion 16 with the inner circumferential end of the outer cutter portion 17 when viewed from the axial direction X. When the cutter 10 of this shape is rotated around the axis L and moved in a direction intersecting the axis L to chamfer the corner 3 of the workpiece 2, as shown in FIG. Figure 3 As shown, the vector V1 of the cutting force applied to the corner 3 of the workpiece 2 from the inner cutter portion 16 and the vector V2 of the cutting force applied to the corner 3 of the workpiece 2 from the outer cutter portion 17 are directed toward the center in the width direction of the chamfered surface 5 formed by cutting. In addition, the flow of chips caused by cutting is directed toward the curved cutter portion 18 between the inner cutter portion 16 and the outer cutter portion 17. Thus, the generation of Poisson burrs at the edge of the chamfered surface 5 formed by cutting can be suppressed.

[0054] In addition, in the chamfering knife 1 of the present example, the cutter 10 is composed of an inner cutter portion 16, an outer cutter portion 17 and a curved cutter portion 18. The inner cutter portion 16 extends linearly toward the outer peripheral side and toward the rear R2 of the rotation direction R when viewed from the axial direction X, and the outer cutter portion 17 extends linearly toward the outer peripheral side and toward the front R1 of the rotation direction R from the radial outside of the inner cutter portion 16. The curved cutter portion 18 connects the end portion of the outer peripheral side of the inner cutter portion 16 with the end portion of the inner peripheral side of the outer cutter portion 17. Therefore, even if the positional relationship between the chamfering knife 1 and the corner 3 of the workpiece 2 is offset in a direction orthogonal to the moving direction M, the contact angle between the cutter 10 and the workpiece 2 can be maintained.

[0055] That is, when the workpiece 2 is a casting, the position of the corner 3 of the workpiece 2 caught by the machine tool may be offset in a direction orthogonal to the moving direction M of the chamfering cutter 1 due to tolerance. In this case, when the machine tool brings the blade 11 of the chamfering cutter 1 into contact with the workpiece 2, the radial center 10a of the cutter 10 may not coincide with the center of the width direction of the preset ideal chamfered surface 5. Figure 4 Compared with the state shown in Figure 5 In the example shown, the radial center 10a of the cutter 10 is offset to the lower side of the inclination direction of the ideal chamfered surface 5. Figure 4 Compared with the state shown in Figure 5 In the example shown, the cutter 10 is in shallow contact with the corner 3 of the workpiece 2 .

[0056] Even in this case, in the chamfering cutter 1 of this example, the inner cutter portion 16 and the outer cutter portion 17 are both extended in a straight line, so the contact angle between the workpiece 2 and the cutter 10 is maintained. That is, even in the case where the cutter 10 is in shallow contact with the corner 3 of the workpiece 2, as shown in FIG. Figure 4 , Figure 5 As shown, the contact angle between the inner cutter portion 16 and the workpiece 2 is maintained at the inclination angle θ1 of the inner cutter portion 16 relative to the radial direction. Therefore, the accuracy of chamfering (cutting) can be maintained, and the generation of Poisson burrs can be suppressed.

[0057] Here, such effects are described in more detail using a tool of a comparative example. Figure 6 As shown, the shape of the chamfering cutter 51 of the comparative example when the cutter 50 is viewed from the axial direction X is an arc shape. In addition, although not shown in the figure, the chip discharge groove 13 of the chamfering cutter 51 of the comparative example is provided in a spiral around the axis L. In addition, except for the shape of the cutter 50 and the shape of the chip discharge groove 13, the chamfering cutter 51 of the comparative example includes the same structure as the chamfering cutter 1 of the present example.

[0058] When the chamfering cutter 51 of the comparative example is brought into contact with the corner 3 of the workpiece 2, as shown in FIG. Figure 6 As shown in (a), first, an ideal chamfered surface 5 is set. Then, the chamfering cutter 51 is arranged in such a manner that the radial center 50a of the cutter 50 is located at the center in the width direction of the ideal chamfered surface 5. Then, the chamfering cutter 51 is moved along the moving direction M in a state where the center in the width direction of the ideal chamfered surface 5 is aligned with the radial center 50a of the cutter 50. As a result, a chamfered surface 5 is formed at the corner 3 of the workpiece 2, and the chamfered surface 5 is inclined at the same angle as the angle at which the cutter 50 is inclined relative to the axis L and extends along the moving direction M.

[0059] Here, in the chamfering blade 51 of the comparative example, the end portion 50b on the inner peripheral side of the cutting blade 50 is bent toward the outer peripheral side and toward the rear R2 in the rotation direction R. In addition, the end portion 50c on the outer peripheral side of the blade 50 is bent toward the outer peripheral side and toward the front R1 in the rotation direction R. Therefore, similarly to the chamfering blade 1, Figure 3 In the case of the chamfering cutter 1 shown in FIG. 1 , the vector V1 of the cutting force applied to the corner 3 of the workpiece 2 from the end portion 50b on the inner peripheral side of the cutter 50 and the vector V2 of the cutting force applied to the corner 3 of the workpiece 2 from the end portion 50c on the outer peripheral side of the cutter 50 are directed toward the center in the width direction of the chamfered surface 5 formed by cutting. In addition, the flow of chips caused by cutting is directed toward the curved cutter portion 18 between the inner cutter portion 16 and the outer cutter portion 17. Thus, the generation of Poisson burrs at the edge of the chamfered surface 5 formed by cutting can be suppressed.

[0060] However, when the position of the corner 3 of the workpiece 2 stuck by the machine tool is shifted in a direction orthogonal to the moving direction M of the chamfering cutter 51, the contact angle between the workpiece 2 and the cutter 50 cannot be maintained. Figure 6 As shown in (b), when the cutter 50 is in shallow contact with the corner 3 of the workpiece 2 and the radial center 50a of the cutter 50 is offset to the lower side of the inclination direction of the chamfered surface 5 compared to the center of the ideal chamfered surface 5, the end portion 50b on the inner circumference side of the cutter 50 does not contact the workpiece 2. Then, instead of the end portion 50b on the inner circumference side of the cutter 50, the central portion 50d of the cutter 50 contacts the workpiece 2. Here, when the central portion 50d of the cutter 50 contacts the corner 3 of the workpiece 2, the contact angle of the central portion 50d of the cutter 50 and the workpiece 2 is deeper than the inclination angle θ1 of the end portion 50b on the inner circumference side of the cutter 50 (θ1+α). As a result, compared with the case where the end portion 50b on the inner circumference side of the blade 11 contacts the corner 3 of the workpiece 2, the vector V1 of the cutting force applied from the central portion 50d of the cutter 50 to the corner 3 of the workpiece 2 becomes larger. In addition, the direction of the vector V1 is toward the outside in the width direction of the chamfered surface 5, compared to the case where the inner peripheral end portion 50b of the blade 11 contacts the corner 3 of the workpiece 2. Moreover, the flow of chips caused by cutting is toward the downward direction of the inclination direction of the chamfered surface 5 formed by cutting.

[0061] As a result, in the chamfering cutter 51 of the comparative example, when the positional relationship between the corner 3 of the workpiece 2 and the chamfering cutter 51 deviates from the preset positional relationship, the accuracy of chamfering (cutting) varies compared to the case where the chamfering cutter 1 is used. In addition, when the chamfering cutter 51 of the comparative example is used, if the positional relationship between the corner 3 of the workpiece 2 and the chamfering cutter 51 deviates from the preset positional relationship, Poisson burrs are easily generated.

[0062] Here, in this example, the first angle θ1 of the inner cutter portion 16 and the second angle θ2 of the outer cutter portion 17 are greater than 25° and less than 45°. If the first angle θ1 and the second angle θ2 are within such a range, the effect of suppressing the generation of Poisson burrs is significant. In addition, if the first angle θ1 and the second angle θ2 are within such a range, the shape of the cutter 10 when viewed from the axial direction X opens more than 90° toward the front R1 of the rotation direction R to form a substantially V-shaped shape, so it is easy to form the cutter 10 on the blade portion 11.

[0063] In addition, as long as the first angle θ1 of the inner cutter portion 16 and the second angle θ2 of the outer cutter portion 17 are 5° or more, the effect of suppressing the generation of Poisson burrs can be found. In other words, when the first angle θ1 and the second angle θ2 are less than 5°, it is difficult to find the effect of suppressing the generation of Poisson burrs. In addition, if the first angle θ1 of the inner cutter portion 16 and the second angle θ2 of the outer cutter portion 17 are set to 70° or less, it is easy to form the cutter 10 on the blade portion 11. In other words, when the first angle θ1 and the second angle θ2 are greater than 70°, it is difficult to form the blade portion 11 on the blade portion 11. Here, compared with the case of setting the cutter 10 with both the first angle θ1 and the second angle θ2 being less than 45°, the formation of the cutter 10 becomes difficult, but the cutter 10 can be easily formed by setting the curved cutter portion 18 including the arc longer in the radial direction.

[0064] In addition, in this example, the first angle θ1 at which the inner cutter portion 16 is inclined relative to the radial rearward direction X2 is larger than the second angle θ2 at which the outer cutter portion 17 is inclined relative to the radial frontward direction X1. Therefore, the generation of Poisson burrs can be suppressed at both end edges in the width direction of the chamfered surface 5. That is, when the chamfering cutter 1 is rotated, the peripheral speed of the outer cutter portion 17 located on the outer peripheral side is faster than the peripheral speed of the inner cutter portion 16. Therefore, the cutting force of the outer cutter portion 17 is higher than the cutting force of the inner cutter portion 16. Therefore, in the workpiece 2, the end edge on one side of the chamfered surface 5 in the width direction after chamfering by the outer cutter portion 17 can suppress the generation of Poisson burrs compared to the end edge on one side of the chamfered surface 5 in the width direction after chamfering by the inner cutter portion 16. In other words, the cutting force of the inner cutter portion 16 is lower than the cutting force of the outer cutter portion 17. Therefore, in the workpiece 2, there is a problem that Poisson burrs are more likely to be generated at the other end edge of the chamfered surface 5 chamfered by the inner cutter portion 16 than at one end edge in the width direction of the chamfered surface 5 chamfered by the outer cutter portion 17. In order to solve this problem, in this example, the first angle θ1 of the inner cutter portion 16 is made larger than the second angle θ2 of the outer cutter portion 17. As a result, the vector V1 of the cutting force applied to the workpiece 2 from the inner cutter portion 16 can be directed toward the center of the width direction of the chamfered surface 5 formed by cutting more than the vector V2 of the cutting force applied to the workpiece 2 from the outer cutter portion 17. Therefore, the generation of Poisson burrs at the edge of the chamfered surface 5 formed by cutting by the inner cutter portion 16 can be suppressed.

[0065] In addition, in this example, the difference between the first angle θ1 and the second angle θ2 is 2° or more and 10° or less. Therefore, it is easy to set the bending point P of the arc of the curved cutter portion 18 located between the inner cutter portion 16 and the outer cutter portion 17 in the radial direction to a position close to the imaginary circle C passing through the radial center 50a of the cutter 50. Here, if the bending point P is set to a position close to the imaginary circle C, even if the position of the corner 3 of the workpiece 2 is offset in a direction orthogonal to the moving direction M of the chamfering cutter 1, both end edges in the width direction of the ideal chamfered surface 55 can be cut by the inner cutter portion 16 and the outer cutter portion 17. Therefore, the generation of Poisson burrs can be suppressed.

[0066] Furthermore, in the above example, the curved cutter portion 18 connecting the inner cutter portion 16 and the outer cutter portion 17 includes an arc, and the bending point P of the arc of the curved cutter portion 18 is located at a position closer to the inner circumference than the imaginary circle C. Therefore, it is easy to make the first angle θ1 of the inner cutter portion 16 larger than the second angle θ2 of the outer cutter portion 17.

[0067] In addition, the shapes of the inner blade portion 16, the outer blade portion 17, and the curved blade portion 18 may be set so that the curved point P is located on the imaginary circle C.

[0068] In the above example, the curved cutter portion 18 is an arc shape including an arc when viewed from the axial direction X, but the curved cutter portion 18 may be an intersection where the inner cutter portion 16 extending linearly and the outer cutter portion 17 extending linearly intersect. That is, the cutter 10 may be a V-shaped shape where the inner cutter portion 16 and the outer cutter portion 17 intersect acutely at a predetermined angle at the curved cutter portion 18.

[0069] Here, in this example, the chip discharge groove 13 extends linearly along the axial direction X. Therefore, compared with the case where the chip discharge groove 13 is provided in a spiral around the axis L, the chamfering cutter 51 can be manufactured more easily.

[0070] In addition, in the above example, the chamfering action is performed by moving the chamfering cutter 51 in a direction intersecting the axis L, but even if the cutter portion 11 is inserted into a hole formed in the workpiece 2 and the opening edge of the hole in the workpiece 2 is chamfered, the generation of Poisson burrs can be suppressed.

[0071] (Variation Example)

[0072] In the above example, the blade 11 includes the flat portion 15 at the center of the front end, but it is not necessary to include the flat portion 15. That is, the blade 11 includes a conical portion whose front end tapers toward the front X1 instead of the flat portion 15. In addition, a second cutter different from the above-mentioned cutter 10 may be provided in the conical portion.

[0073] then, Figure 7 It is a partial perspective view of the vicinity of the blade portion 11 of the chamfering blade of the modified example. The chamfering blade 1A of this example includes the same configuration as the chamfering blade 1 described above, and therefore, the same reference numerals are given to the corresponding configurations and their descriptions are omitted.

[0074] like Figure 7 As shown, the chamfering blade 1A includes a truncated cone-shaped blade portion 11 at the front X1 of the shaft portion 12. That is, the blade portion 11 includes a flat portion 15 at the center of the front end. In addition, the blade portion 11 includes a tapered outer peripheral surface 31 that increases in diameter from the flat portion 15 toward the rear X2.

[0075] On the front end side of the tapered outer peripheral surface 31, there is provided an inner rib 32 extending linearly toward the outer peripheral side and toward the rear R2 of the rotation direction R. In this example, eight inner ribs 32 are provided at equal angle intervals. The cross-sectional shape of the inner rib 32 is a rectangle. In addition, on the radially outer side of each inner rib 32 of the tapered outer peripheral surface 31, there is provided an outer rib 33 extending linearly toward the outer peripheral side and toward the front R1 of the rotation direction R. There are eight outer ribs 33 provided at equal angle intervals. The cross-sectional shape of the outer rib 33 is a rectangle. The end of the outer peripheral side of the inner rib 32 and the end of the inner peripheral side of the outer rib 33 overlap when viewed from the circumferential direction. That is, the end of the outer peripheral side of the inner rib 32 protrudes further toward the outer peripheral side than the end of the inner peripheral side of the outer rib 33.

[0076] An inner cutter portion 16 constituting the cutter 10 is provided at a corner portion located at the front R1 in the rotation direction R on the outer peripheral side of the inner rib 32. An outer cutter portion 17 constituting the cutter 10 is provided at a corner portion located at the front R1 in the rotation direction R on the outer peripheral side of the outer rib 33. The inner cutter portion 16 extends linearly toward the outer peripheral side and toward the rear R2 in the rotation direction R. The outer cutter portion 17 extends linearly toward the outer peripheral side and toward the front R1 in the rotation direction R from the radially outer side of the inner cutter portion 16. The end portion of the outer peripheral side of the inner cutter portion 16 and the end portion of the inner peripheral side of the outer cutter portion 17 overlap when viewed from the circumferential direction. That is, the end portion of the outer peripheral side of the inner cutter portion 16 protrudes further toward the outer peripheral side than the end portion of the inner peripheral side of the outer cutter portion 17.

[0077] The chamfering tool 1A of this example can also achieve the same operation and effects as those of the chamfering tool 1 described above.

[0078] (Example 2)

[0079] Figure 8 This is an appearance diagram of the chamfering cutter of Example 2. Fig. 9 Observed from the blade side Figure 8In addition, the chamfering cutter 1B of the second embodiment includes a structure corresponding to the chamfering cutter 1 described above, and therefore, the corresponding structures are marked with the same symbols and their descriptions are omitted.

[0080] like Figure 8 As shown, the chamfering tool 1B includes: a blade portion 11 including a cutter 10; and a shaft portion 12 coaxial with the blade portion 11. The cutter 10 is arranged along the radially outer edge of the blade portion 11. The shaft portion 12 is cylindrical. The shaft portion 12 is connected to the head of the machine tool. The chamfering tool 1B rotates along a predetermined rotation direction R around the axis L of the shaft portion 12 while moving in a direction intersecting the axis L, thereby chamfering the corner 3 of the workpiece 2.

[0081] The blade 11 is provided continuously in front of the shaft 12 at X1. The blade 11 includes a flat portion 15 at the center of the front end. In addition, the blade 11 includes a blade bending portion 11a, and the blade bending portion 11a is bent toward the second direction X2 (the side of the shaft 12) at the radially outer edge when viewed from the direction orthogonal to the axis L. Thus, the cutter 10 provided along the radially outer edge of the blade 11 includes: a first portion 61, which extends linearly from the end of the outer peripheral side of the flat portion 15 toward the second direction X2 toward the outer peripheral side when viewed from the direction orthogonal to the axis of the shaft 12; a bent portion 62, which bends toward the second direction X2 from the end of the second direction X2 of the first portion 61 toward the second direction X2 when viewed from the direction orthogonal to the axis of the shaft 12; and a second portion 63, which extends linearly toward the second direction X2 from the end of the outer peripheral side of the bent portion 62 toward the outer peripheral side. The end of the first portion 61 in the second direction X2 and the curved portion 62 are continuous without any step. In addition, the curved portion 62 and the end of the second portion 63 on the inner peripheral side are continuous without any step.

[0082] In addition, the knife portion 11 includes a chip discharge groove 13 adjacent to the cutter 10. The chip discharge groove 13 is located at a position R1 in front of the rotation direction R relative to the cutter 10. In this example, the knife portion 11 includes four cutters 10 at equal angular intervals around the axis L. Therefore, the knife portion 11 includes four chip discharge grooves 13 at equal angular intervals around the axis L. Each chip discharge groove 13 opens radially outward. The opening edge of each chip discharge groove 13 in the knife portion 11 includes a front opening edge portion 13a located in front of R1 in the rotation direction R and a rear opening edge portion 13b located behind the rotation direction R. Here, the cutter 10 can be set at the rear opening edge portion 13b.

[0083] like Fig. 9As shown, each cutter 10 is composed of an inner cutter portion 16, an outer cutter portion 17, and a curved cutter portion 18. The inner cutter portion 16 extends linearly toward the outer circumference and toward the rear R2 in the rotation direction R when viewed from the axial direction X. The outer cutter portion 17 extends linearly toward the outer circumference and toward the front R1 in the rotation direction R from the radially outer side of the inner cutter portion 16 when viewed from the axial direction X. The curved cutter portion 18 is located between the outer circumferential end of the inner cutter portion 16 and the inner circumferential end of the outer cutter portion 17 when viewed from the axial direction X. The curved cutter portion 18 is a portion connecting the outer circumferential end of the inner cutter portion 16 and the inner circumferential end of the outer cutter portion 17. The curved cutter portion 18 is curved. The curved cutter portion 18 is recessed toward the rear R2 in the rotation direction R.

[0084] The core height of the inner cutter portion 16 is set to an amount equivalent to the dimension H1. In other words, when a virtual plane S1 parallel to the inner cutter portion 16 and including the axis L is defined, the inner cutter portion 16 is located at a position equivalent to the dimension H1 from the rear R2 in the rotation direction R to the front R1 in the rotation direction R. The curved cutter portion 18 is provided in the curved portion 62. In other words, the curved cutter portion 18 is provided so as to completely overlap the curved portion 62 or is provided inside the curved portion 62. Therefore, when viewed from a direction orthogonal to the axis, the curved cutter portion 18 is located between the first portion 61 and the second portion X2 in the axial direction X.

[0085] In this example, the curved cutter portion 18 and the curved portion 62 completely overlap. Therefore, the portion (curved portion) of the cutter 10 that curves toward the outer peripheral side toward the second direction X2 when viewed from the direction orthogonal to the axis L curves toward the rear R2 of the rotation direction R when viewed from the axis direction X. In addition, the inner cutter portion 16 and the first portion 61 completely overlap, and the outer cutter portion 17 and the second portion 63 completely overlap. Therefore, the portion (inner cutter portion 16) of the cutter 10 that extends linearly toward the rear R2 of the rotation direction R toward the outer peripheral side when viewed from the direction orthogonal to the axis L extends linearly toward the outer peripheral side toward the second direction X2 when viewed from the axis direction X. In addition, the portion (outer cutter portion 17) of the cutter 10 that extends linearly toward the front R1 of the rotation direction R toward the outer peripheral side when viewed from the direction orthogonal to the axis L extends linearly along the second direction X2 toward the outer peripheral side when viewed from the axis direction X.

[0086] Here, of the end 16a on the inner circumferential side of the inner cutter portion 16 and the end 17a on the outer circumferential side of the outer cutter portion 17, the end 17a on the outer circumferential side of the outer cutter portion 17 is located in front R1 of the rotation direction R. The first angle θ1 at which the inner cutter portion 16 is inclined toward the rear X2 with respect to the radial direction and the second angle θ2 at which the outer cutter portion 17 is inclined toward the front X1 with respect to the radial direction are respectively greater than 5° and less than 85°. Here, preferably, the first angle θ1 at which the inner cutter portion 16 is inclined is greater than the second angle θ2 at which the outer cutter portion 17 is inclined. In this example, the first angle θ1 is 79° and the second angle θ2 is 19°. The difference between the first angle θ1 and the second angle θ2 is 60°. In addition, the bending point 18a of the curved shape of the curved cutter portion 18 is located at a position closer to the inner circumference than the imaginary circle C passing through the center 10a of the cutter 10 in the radial direction. Furthermore, the inner peripheral end 16 a of the inner cutter portion 16 and the outer peripheral end 17 a of the outer cutter portion 17 may be located at the same angular position around the axis L.

[0087] In this example, as long as the first angle θ1 of the inner cutter portion 16 and the second angle θ2 of the outer cutter portion 17 are 5° or more, the effect of suppressing the generation of Poisson burrs can be found. In other words, when the first angle θ1 and the second angle θ2 are less than 5°, it is difficult to find the effect of suppressing the generation of Poisson burrs. In addition, if the first angle θ1 of the inner cutter portion 16 and the second angle θ2 of the outer cutter portion 17 are set to 85° or less, it is easy to form the cutter 10 on the knife portion 11. Here, in this example, the inner cutter portion 16 and the outer cutter portion 17 are not arranged on the same plane as the cutter 10 of the chamfering knife 1 of Example 1. Therefore, even if the first angle θ1 and the second angle θ2 exceed 70°, it is easy to set the cutter 10 on the knife portion 11. In addition, in this example, the curved cutter portion 18 overlaps with the curved portion 62, and the arc of the curved cutter portion 18 is larger than that of the chamfering knife 1 of Example 1. From this point of view, in this example, even when the first angle θ1 and the second angle θ2 exceed 70°, it is easy to install the cutter 10 on the blade portion 11 .

[0088] (Chamfering action)

[0089] Fig.10 This is an explanatory diagram of a chamfering operation in which a corner portion 3 of a workpiece 2 is chamfered by a chamfering cutter 1B. When the chamfering operation is performed, the chamfering cutter 1B is connected to a machine tool and rotated along a predetermined rotation direction R around an axis L. Then, the cutter portion 11 is brought into contact with the corner portion 3 of the workpiece 2 and the chamfering cutter 1B is moved along a moving direction M orthogonal to the axis L, thereby forming a chamfered surface 5. Thus, a chamfered surface 5 extending along the moving direction M in a curved shape after the curved portion 62 is transferred is formed at the corner portion 3 of the workpiece 2.

[0090] Here, with Figure 4 Similarly, in the chamfering knife 1B of this example, the cutter 10 is composed of an inner cutter portion 16, an outer cutter portion 17 and a curved cutter portion 18. The inner cutter portion 16 extends linearly toward the outer circumference and toward the rear R2 of the rotation direction R when viewed from the axial direction X, and the outer cutter portion 17 extends linearly toward the outer circumference and toward the front R1 of the rotation direction R from the radially outer side of the inner cutter portion 16 when viewed from the axial direction X. The curved cutter portion 18 is located between the outer circumferential end of the inner cutter portion 16 and the inner circumferential end of the outer cutter portion 17. Therefore, as Fig.10 As shown, the vector V1 of the cutting force applied to the corner 3 of the workpiece 2 from the inner peripheral end portion of the curved cutter portion 18 and the inner cutter portion 16, and the vector V2 of the cutting force applied to the corner 3 of the workpiece 2 from the outer peripheral end portion of the curved cutter portion 18 and the outer cutter portion 17 are directed toward the center in the width direction of the chamfered surface 5 formed by cutting. In addition, the flow of chips caused by cutting is directed toward the curved cutter portion 18 between the inner cutter portion 16 and the outer cutter portion 17. As a result, the generation of Poisson burrs at the edge of the chamfered surface 5 formed by cutting can be suppressed.

[0091] In addition, in the chamfering knife 1B of this example, the cutter 10 is composed of an inner cutter portion 16, an outer cutter portion 17 and a curved cutter portion 18. The inner cutter portion 16 extends linearly toward the outer peripheral side and toward the rear R2 of the rotation direction R when viewed from the axial direction X, and the outer cutter portion 17 extends linearly toward the outer peripheral side and toward the front R1 of the rotation direction R from the radial outside of the inner cutter portion 16. The curved cutter portion 18 connects the end portion located on the outer peripheral side of the inner cutter portion 16 with the end portion on the inner peripheral side of the outer cutter portion 17. Therefore, Figure 5 Similarly to the case shown in (b), even when the positional relationship between the chamfering cutter 1B and the corner portion 3 of the workpiece 2 is shifted in a direction perpendicular to the moving direction M, the contact angle between the cutter 10 and the workpiece 2 can be maintained.

[0092] Furthermore, in this example, the first angle θ1 at which the inner cutter portion 16 is inclined in the radial direction rearward X2 is larger than the second angle θ2 at which the outer cutter portion 17 is inclined in the radial direction forward X1. Therefore, even if the cutting force of the inner cutter portion 16 due to the peripheral speed is smaller than the cutting force of the outer cutter portion 17, the vector V1 of the cutting force applied to the workpiece 2 from the inner cutter portion 16 can be directed more toward the center of the width direction of the chamfered surface 5 than the vector V2 of the cutting force applied to the workpiece 2 from the outer cutter portion 17. Therefore, the generation of Poisson burrs at the edge of the chamfered surface 5 formed by cutting of the inner cutter portion 16 can be suppressed.

Claims

1. A chamfering tool, comprising: a blade portion including a cutter; and a shaft portion coaxial with the blade portion, wherein the cutter is arranged along the radial end edge of the blade portion and rotates around the axis of the shaft portion along a predetermined rotation direction to chamfer the corner of a workpiece, characterized in that: When observing the knife portion from the axial direction, the cutting knife includes: an inner cutter portion extending linearly toward the outer circumference and rearward in the rotation direction; and an outer cutter portion, the outer cutter portion extending linearly toward the outer circumference and forward in the rotation direction from the radially outer side of the inner cutter portion, The cutter includes a curved cutter portion located between an end portion on an outer peripheral side of the inner cutter portion and an end portion on an inner peripheral side of the outer cutter portion.

2. The chamfering cutter according to claim 1, characterized in that: The cutter is linearly inclined toward the shaft portion toward the outer circumference when viewed from a direction perpendicular to the axis of the shaft portion.

3. The chamfering cutter according to claim 2, characterized in that: The knife portion includes a chip discharge groove adjacent to the cutter in front of the rotation direction, The chip discharge groove extends linearly along the axial direction.

4. The chamfering cutter according to claim 2, characterized in that: An end portion on an inner peripheral side of the inner cutter portion and an end portion on an outer peripheral side of the outer cutter portion are located at the same angular position around the axis.

5. The chamfering cutter according to claim 2, characterized in that: The first angle at which the inner cutter portion is inclined rearward relative to the radial direction and the second angle at which the outer cutter portion is inclined forward relative to the radial direction are respectively not less than 5° and not more than 70°.

6. The chamfering cutter according to claim 5, characterized in that: The first angle is greater than the second angle.

7. The chamfering cutter according to claim 6, characterized in that: The difference between the first angle and the second angle is greater than or equal to 2° and less than or equal to 10°.

8. The chamfering cutter according to claim 2, characterized in that: When the blade portion is viewed from a direction perpendicular to the axis, the cutter is inclined at 45° with respect to the axis.

9. The chamfering cutter according to claim 1, characterized in that: An end portion of the inner cutter portion of the cutter on an outer peripheral side overlaps an end portion of the outer cutter portion on an inner peripheral side when viewed from a circumferential direction.

10. The chamfering cutter according to claim 2, characterized in that: The cutter includes a curved portion that curves toward the outer peripheral side toward the shaft portion when viewed from a direction orthogonal to the axis of the shaft portion. The curved cutter portion is disposed at the curved portion.

11. The chamfering cutter according to claim 10, characterized in that: The cutter includes: a first portion, which extends linearly toward the shaft side and toward the outer periphery when viewed from a direction orthogonal to the axis of the shaft; a bent portion, which is bent from an end of the first portion on the shaft side; and a second portion, which extends linearly toward the shaft side from an end of the outer periphery of the bent portion toward the outer periphery.

12. The chamfering cutter according to claim 10, characterized in that: The first angle at which the inner cutter portion is inclined rearward relative to the radial direction and the second angle at which the outer cutter portion is inclined forward relative to the radial direction are respectively not less than 5° and not more than 85°.

13. The chamfering cutter according to claim 12, characterized in that: The first angle is greater than the second angle.

14. A method for chamfering a workpiece, characterized in that: The chamfering cutter according to claim 1 is caused to contact the corner of the workpiece while rotating about the axis and to move in a direction intersecting the axis.

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