JP3786904B2 - Total rotary cutting tool - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotary cutting tool, and more particularly to an improvement of a general rotary cutting tool in which the edge diameter of an outer peripheral cutting edge continuously changes in the axial direction.
[0002]
[Prior art]
Corresponding to the rotation trajectory of the outer peripheral cutting edge by having an outer peripheral cutting edge whose cutting edge diameter continuously changes in the axial direction and being moved in a direction perpendicular to the axial center while being driven to rotate around the axial center. Japanese Patent Application Laid-Open No. 11-245112 discloses a general-purpose rotary cutting tool for performing shape cutting, for example, grooving. The flank of the outer peripheral cutting edge of such a general rotary cutting tool is provided by relatively approaching the grinding wheel while rotating the tool around the axis, and is continuously formed in the circumferential direction from the cutting edge. For example, as shown in FIG. 6, in the state where the outer peripheral cutting edge 100 is developed around the axis, the clearance angle α with a constant diameter of the flank 102 with respect to the straight line D with a constant diameter is provided. The clearance dimension δ (θ) increases linearly with respect to the rotation angle θ (°) from the blade edge 104, or linearly decreases at (°). In the former, since the clearance dimension δ is determined according to the distance from the blade edge 104, the clearance dimension δ (θ) at a predetermined rotation angle θ (for example, 90 °) changes with the dimensional change of the blade edge diameter, and the blade edge diameter becomes smaller. The smaller the smaller the clearance dimension δ (θ) at the same rotation angle θ, whereas the latter, the clearance dimension δ (θ) at the rotation angle θ (for example, 90 °) from the blade edge 104 is a dimensional change in the blade edge diameter. Regardless, it is constant.
[0003]
[Problems to be solved by the invention]
However, even if the grinding wheel is relatively approached while the tool is rotated about the axis as described above to form the flank of the outer peripheral cutting edge, the axial center in the cross section including the axis of the rotation trajectory of the outer peripheral cutting edge. In a steeply inclined portion with an inclination angle of 60 ° or more with respect to the axial direction, the axial relief amount becomes small, the sharpness is lowered, and the tool life may be impaired. For example, FIG. 2 (b) shows the amount of axial clearance (flank angle) when a predetermined flank machining is performed in the circumferential direction at a steeply inclined portion with an inclination angle Φ of 60 ° or more with respect to the tool axis. In the figure showing an example, the larger the inclination angle Φ, the smaller the axial clearance becomes, and the above problem becomes remarkable. The amount of relief in the axial direction of FIG. 2 is a relief angle when deployed around the axis as in FIG.
[0004]
Increasing the circumferential clearance increases the axial clearance as well. However, as described above, in a steeply inclined portion with an inclination angle Φ of 60 ° or more, the axial direction can be increased by simply increasing the circumferential clearance. It is difficult to secure a sufficient amount of escape.
[0005]
The present invention has been made against the background described above, and its object is to improve the tool life by obtaining a predetermined sharpness even in a portion where the inclination angle Φ with respect to the axis is large.
[0006]
[Means for Solving the Problems]
In order to achieve such an object, the first invention has an outer peripheral cutting edge whose cutting edge diameter continuously changes in the axial direction, and is rotated around the axis to rotate the outer peripheral cutting edge. In the full-form rotary cutting tool that performs a cutting process corresponding to the shape of the outer peripheral cutting edge, a cross-section including the axis of the rotation locus of the outer peripheral cutting edge has a predetermined inclination angle of 60 ° or more and less than 90 °. The steeply inclined portion is characterized in that flank machining is performed by relatively moving a grinding wheel in a direction including an axial component.
[0007]
The second invention has an outer peripheral cutting edge whose cutting edge diameter continuously changes in the axial direction, and is driven to rotate around the axis to perform a cutting process corresponding to the rotation trajectory of the outer peripheral cutting edge. In the overall rotary cutting tool to be performed, the outer peripheral cutting edge is an arc portion curved with a predetermined radius of curvature in a cross section including the axis of the rotation locus, and is ± 30 ° or less from a direction parallel to the axis. A predetermined steep slope portion having a central angle is characterized in that flank machining is performed by relatively moving a grinding wheel in a direction including an axial component.
[0008]
According to a third aspect of the present invention, in the overall rotary cutting tool according to the first or second aspect of the present invention, the flank machining is performed within a range where the axial flank amount is 30 ′ to 10 ° when the flank surface is unfolded around the axis. It is characterized by being applied.
[0009]
【The invention's effect】
In the overall rotary cutting tool according to the first aspect of the present invention, the grinding wheel is relatively moved in a direction including the axial direction component at a predetermined steeply inclined portion having an inclination angle with respect to the axis of 60 ° or more and less than 90 °, and the flank face Since the machining is performed, it is possible to easily secure a sufficient amount of axial relief, and the sharpness of the steeply inclined portion is improved, resulting in a longer tool life.
[0010]
The second invention is a case where the outer peripheral cutting edge has an arc portion, and the central angle from the direction parallel to the axis of the arc portion is ± 30 ° or less, that is, the inclination angle with respect to the axis of the arc tangent Since the flank machining is performed by moving the grinding wheel relatively in the direction including the axial direction component at a portion of 60 ° or more, substantially the same effect as the first invention is obtained.
[0011]
In the third invention, the flank face is processed so that the axial flank amount is in the range of 30 ′ to 10 °, so that the sharpness can be improved without impairing the shape (form) of the outer peripheral cutting edge. it can. That is, although it depends on the inclination angle of the steeply inclined portion, generally, if the axial clearance is smaller than 30 ', the effect of improving the sharpness cannot be obtained sufficiently, and if it exceeds 10 °, the shape of the outer peripheral cutting edge may be impaired. There is.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The general-purpose rotary cutting tool of the present invention is driven to rotate around the shaft center and is relatively moved with respect to the work material in a direction intersecting the shaft center. Although the side surface processing is performed, it is preferably applied particularly when the relative movement is performed in a direction perpendicular to the axis.
[0013]
In the first invention, it is desirable to apply to all steeply inclined portions having an inclination angle of 60 ° or more, but it may be applied only to a part such as an inclination angle of 75 ° or more. Conversely, the inclination angle is 60 ° or less. May be included. The second invention substantially corresponds to an embodiment of the first invention, and is preferably applied to all steeply inclined portions of ± 30 ° or less from a direction parallel to the axis, but ± 15 ° or less, etc. May be applied only to a part of the angle, and conversely, a part having a central angle of ± 30 ° or more may be included. The center angle ± from the direction parallel to the axis is intended to include both the direction approaching the axis and the direction away from the axis with respect to the straight line parallel to the axis.
[0014]
The second invention relates to the arc portion, but when the first invention is carried out, the invention is applied to various shapes such as a straight portion whose diameter dimension changes linearly in the axial direction. The straight line portion and the arc portion of the second invention have a shape in a cross section including the axis of the rotation locus of the outer peripheral cutting edge, in other words, a shape of a change in the radial dimension of the outer peripheral cutting edge in the axial direction. It does not have to be a straight line or an arc.
[0015]
The flank machining of the first invention and the second invention grinds the flank by relatively moving the grinding wheel in a direction including the axial component of the tool. For example, the grinding wheel is rotated while rotating the tool around the axis. Is moved in the axial direction to perform flank machining, and the axial clearance is appropriately determined by the moving speed of the grinding wheel in the axial direction relative to the rotational speed of the tool. A predetermined relief can also be provided in the axial direction and the circumferential direction by moving the grinding wheel closer to the tool while relatively moving in the axial direction. The flank machining by relative movement in the direction including the axial direction component is performed only on a predetermined steep slope after the circumferential flank machining is performed on all outer peripheral cutting edges including the steep slope, for example. However, for the steeply inclined portion, the flank machining in the direction including the axial direction component may be performed without performing the flank machining in the circumferential direction.
[0016]
The flank of the outer peripheral cutting edge may be provided leaving a predetermined margin regardless of whether or not it is a steeply inclined portion, but it is also possible to provide the flank without a margin.
[0017]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram for explaining a general rotary cutting tool 10 according to an embodiment of the present invention, in which (a) is a front view with a part cut away showing a blade part at the tip, and (b) is (a). BB sectional drawing in (b), (c) is the bottom view seen from the front end side. The total rotary cutting tool 10 is provided with four chip discharge grooves 12 around the axis S, and four outer peripheral cutting edges 14 along the chip discharge grooves 12 and the outer peripheral cutting edges 14. A bottom blade 16 is provided continuously. The outer peripheral cutting edge 14 and the bottom cutting edge 16 perform cutting by rotating the general-purpose rotary cutting tool 10 clockwise as viewed from the shank side (not shown). Is twisted clockwise with a lead of about 430 mm so that the swarf is well discharged to the shank side, and the outer peripheral cutting edge 14 is a torsional blade twisted about the axis.
[0018]
FIG. 1A is a cross-sectional view of the left half of the axis S. The outlines on both sides represent the rotation trajectory of the outer peripheral cutting edge 14, and the cross section including the axis S of the rotation trajectory. Corresponding to the shape, by being relatively moved with respect to the work material in a direction perpendicular to the axis S, groove processing or side surface processing of the same shape as the rotation trajectory is performed. The outer peripheral cutting edge 14 is provided with a bulging portion 20 that has a blade tip diameter that continuously increases at the tip end portion in the axial direction and smoothly bulges toward the outer peripheral side. Is provided with an arc-shaped arc portion 22 which is curved with a predetermined curvature radius in a cross-sectional shape including the axis S of the rotation locus (the shape of FIG. 1A), and is smoothly connected to the bottom blade 16. Yes. The maximum diameter of the bulging portion 20 is about 20 mm.
[0019]
The outer peripheral cutting edge 14 is subjected to flank machining in the circumferential direction including the bulging portion 20 and the circular arc portion 22 by rotating the general-purpose rotary cutting tool 10 around the axis S while approaching the grinding wheel. The outer peripheral flank 24 is formed continuously with the outer peripheral cutting edge 14 without a margin. The circumferential clearance of the outer peripheral flank 24 is 1.6 mm (1.6 / 90 °) per rotation angle θ = 90 °, but the central angle from the direction parallel to the axis S in the arc portion 22. In the steeply inclined portion 22a where σ is ± 30 ° or less, that is, the inclination angle between the arc tangent and the shaft center S is 60 ° or less, the grinding wheel is moved closer to the entire rotary cutting tool 10 around the shaft S. At the same time, by moving in the axial direction, flank machining is performed in the direction including the axial component, and the axial flank amount (flank angle) in the state of being developed around the axis S is 30 ′ to 10 °. For example, a steeply inclined portion flank 30 that escapes in the axial direction at a rotational angle θ = 25 ° of about 0.09 mm (0.09 / 25 °) is formed so as to be within the range. Further, the bottom blade 16 is provided with a bottom blade second relief surface 26 at a clearance angle of about 4 ° to 6 ° at a predetermined width dimension (for example, about 2 mm) from the blade edge. A bottom blade third flank 28 is formed continuously with the flank 26 at a flank angle of about 11 ° to 13 °. The bottom blade 16 is also retracted so as to be recessed toward the axis S side with a concave angle of about 1 ° to 1 ° 30 ′.
[0020]
In the overall rotary cutting tool 10 of this embodiment, the central angle σ from the direction parallel to the axis S of the arc portion 22 of the outer peripheral cutting edge 14 is ± 30 ° or less, that is, the axis of the arc tangent For the steeply inclined portion 22a having an inclination angle Φ with respect to the center S of 60 ° or more, the grinding wheel is moved in the axial direction while rotating the general-purpose rotary cutting tool 10 around the axis S, thereby causing a predetermined steeply inclined portion flank. Since 30 is formed, it is possible to easily secure a sufficient amount of axial relief, and the sharpness of the steeply inclined portion 22a is improved, resulting in a longer tool life.
[0021]
Further, since the steeply inclined portion flank 30 is provided so that the axial flank amount is within a range of 30 'to 10 °, the sharpness is improved without impairing the shape (foam) of the outer peripheral cutting edge 14. Can be made. That is, although it differs depending on the inclination angle Φ of the steeply inclined portion 22a, generally, if the axial relief is smaller than 30 ', the effect of improving the sharpness cannot be obtained sufficiently, and if it exceeds 10 °, the shape of the outer peripheral cutting edge 14 is impaired. There is a possibility.
[0022]
FIG. 2 (a) shows that, in various steep portions having an inclination angle Φ of 60 ° or more with respect to the axis S, the general rotary cutting tool 10 is rotated around the axis S in the same manner as the steep slope flank 30. By moving the grinding wheel closer while moving it in the axial direction, the flank face is processed in the direction including the axial component to form a steeply inclined flank face with a 10 degree axial flank (flank angle). And when the flank machining is performed in the circumferential direction at a rotation angle θ = 1.6 mm (1.6 / 90 °) per 90 ° as in the outer flank 24 other than the steeply inclined flank 30 (same as above) FIG. 6 is a diagram showing an increase in the axial clearance with 30 ′ as a lower limit. In FIG. 2A, the region A is a portion where the inclination angle Φ is 75 ° or more, that is, the central angle σ is ± 15 ° or less, and the region B is 60 ° to 75 °, that is, the central angle σ is ± 15. In the region A, there is a large increase in the amount of axial clearance, and the effect of improving the sharpness of the outer peripheral cutting edge becomes remarkable, and the steeply inclined portion only in the portion where the inclination angle Φ is 75 ° or more. A flank may be formed. Further, the axial relief may be smaller than 10 °, and in the region A, a sufficient sharpness improving effect can be obtained even if it is about 5 ° or less.
[0023]
Incidentally, using the general rotary cutting tool 10 in which the flank machining is performed on the steeply inclined portion 22a so that the axial relief amount is about 5 °, as shown in FIG. A groove 40 having a dimension W1≈20 mm, a straight part dimension W2≈12 mm, and a groove depth d≈16.5 mm was cut on the work material 42 having a length L≈90 mm under the following processing conditions. However, even when the cutting length is 3600 mm (40 grooves), the noise and vibration due to flank wear and the like, and the finished surface failure are within the allowable range and can be used continuously. Also, in this test, the feed rate is 10 mm / min, but it is possible to cut at twice the 20 mm / min, which can greatly improve the machining efficiency coupled with the decrease in tool replacement due to the tool life. it can. On the other hand, in the conventional product in which only the circumferential flank machining is performed on the outer peripheral cutting edge 14 including the steeply inclined portion 22a, the tool has a 25 groove (cutting length 2250 mm) and the finished surface such as a cutter mark or a burr is defective. It can be seen that the tool life is greatly improved according to the present invention.
(Processing conditions)
Machine: Horizontal dedicated machine material: SNCM material (nickel chrome molybdenum steel)
Cutting oil: Water-insoluble cutting oil Rotational speed: 300 min ^-1
Cutting speed: 18.4 m / min (large diameter part)
Feed: 10mm / min (0.033mm / rev)
[0024]
Next, another embodiment of the present invention will be described.
4 is provided with four chip discharge grooves 52 around an axis S, four outer peripheral cutting edges 54 along the chip discharge grooves 52, and the outer peripheral cutting. A bottom blade 56 continuous with the blade 54 is provided. The outer peripheral cutting edge 54 and the bottom cutting edge 56 perform cutting by rotating the general-purpose rotary cutting tool 50 clockwise when viewed from the shank side (not shown). Is twisted with a lead of about 400 mm in the clockwise direction so as to be discharged well to the shank side, and the outer peripheral cutting edge 54 is a twisting blade twisted around the axis. FIG. 4A is a cross-sectional view of the left half of the axis S, and the outlines on both sides represent the rotation trajectory of the outer peripheral cutting edge 54, and the cross section including the axis S of the rotation trajectory. On the other hand, (b) is a bottom view as viewed from the front end side, and the outer peripheral cutting edge 54 has a predetermined cross-sectional shape (the shape of FIG. 4 (a)) including the axis S of the rotation locus. Arc-shaped arc portions 58 and 60 curved with a radius of curvature are provided.
[0025]
The outer peripheral cutting edge 54 is subjected to flank machining in the circumferential direction by causing the grinding wheel to approach while rotating the general rotary cutting tool 50 around the axis S including the arc portions 58 and 60. On the other hand, of the arc portions 58 and 60, the steeply inclined portions 58a and 60a whose center angle σ is ± 30 ° or less from the direction parallel to the axis S, that is, the inclination angle between the arc tangent and the axis S is 60 ° or less. The flank machining is performed in the direction including the axial component by moving the grinding wheel close to the axis while simultaneously rotating the general rotary cutting tool 50 around the axis S and moving it in the axial direction. A steeply inclined flank face is provided in which the axial flank amount (flank angle) in the state of being developed around S is in the range of 30 ′ to 10 °.
[0026]
Also in this embodiment, the central angle σ from the direction parallel to the axis S of the arc portions 58 and 60 of the outer peripheral cutting edge 54 is ± 30 ° or less, that is, the inclination angle of the arc tangent to the axis S is 60 °. The above steeply inclined portions 58a and 60a are provided with steeply inclined portion flank surfaces that are flank processed in a direction including an axial component and have a predetermined flank amount in the axial direction. Similar effects can be obtained.
[0027]
FIG. 5 is a cross-sectional shape including the axis S of the rotation trajectory of the outer peripheral cutting edge 70 (the shape shown in FIG. 5). The inclination angle Φ with respect to the axis S is 60 ° or more. In the case of having the steeply inclined portions 72 and 74, the linear steeply inclined portions 72 and 74 are also moved by moving the tool around the axis S while moving the grinding wheel in the axial direction and escaping. Surface machining is performed, and a steeply inclined flank surface having an axial flank amount (flank angle) in the range of 30 ′ to 10 ° is provided, so that the same operational effects as in the above embodiment can be obtained.
[0028]
As mentioned above, although the Example of this invention was described in detail based on drawing, these are one embodiment to the last, and this invention is implemented in the aspect which added the various change and improvement based on the knowledge of those skilled in the art. be able to.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram for explaining an overall rotary cutting tool according to an embodiment of the present invention, in which (a) is a front view with a part cut away showing a blade portion at the tip, and (b) is a diagram in (a). BB sectional drawing, (c) is the bottom view seen from the front end side.
FIG. 2 is a diagram showing the relationship between the tilt angle Φ with respect to the shaft center and the amount of relief in the axial direction. (A) is the case where flank machining is performed in the direction including the axial component, and (b) is the circumferential direction. This is a case where only the flank machining is applied.
FIG. 3 is a diagram for explaining the shape of grooving performed to confirm the effect of the present invention.
FIGS. 4A and 4B are diagrams for explaining another embodiment of the present invention, in which FIG. 4A is a front view with a part cut away showing a blade part at the tip, and FIG. 4B is a bottom view seen from the tip side.
FIG. 5 is a diagram for explaining still another embodiment of the present invention, in which a straight steeply inclined portion is provided.
FIG. 6 is a view for explaining a flank face of an outer peripheral cutting edge.
[Explanation of symbols]
10, 50: Total shape rotary cutting tool 14, 54, 70: Peripheral cutting edge 22, 58, 60: Arc part 22a, 58a, 60a, 72, 74: Steeply inclined part σ: Center angle Φ: Inclined angle

Claims (3)

A complete rotary cutting that has an outer peripheral cutting edge whose cutting edge diameter changes continuously in the axial direction, and performs a cutting process corresponding to the rotation trajectory of the outer peripheral cutting edge by being driven to rotate around the axis. In the tool,
Among the outer peripheral cutting edges, in a cross-section including the axis of the rotation locus, a predetermined sharply inclined portion having an inclination angle with respect to the axis of 60 ° or more and less than 90 ° is provided with a grinding wheel in a direction including an axial component. A complete rotary cutting tool characterized in that the flank machining is performed by relative movement. A complete rotary cutting that has an outer peripheral cutting edge whose cutting edge diameter changes continuously in the axial direction, and performs a cutting process corresponding to the rotation trajectory of the outer peripheral cutting edge by being driven to rotate around the axis. In the tool,
Of the outer peripheral cutting edge, a circular arc portion curved with a predetermined radius of curvature in a cross section including the axis of the rotation locus, and a predetermined steeply inclined portion having a central angle of ± 30 ° or less from a direction parallel to the axis Is a general-purpose rotary cutting tool characterized in that flank machining is performed by relatively moving a grinding wheel in a direction including an axial component. The flank machining is performed such that an axial flank amount in a state of being developed around an axis is within a range of 30 'to 10 °. A complete rotary cutting tool.

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