WO2018034136A1 - Cutter for cutting turbine blade connection groove, method for cutting turbine blade connection groove, and method for manufacturing turbine blade connection groove - Google Patents

Abstract

[Problem] To form a Christmas cutter for rough working to a mode in which there is a reduced probability of a breakage caused by forming concave parts in a Christmas cutter for rough working. [Solution] A convex-shaped part (30), for cutting concave parts (41) other than the concave part (410) farthest in the depth direction and convex parts (42) other than the convex part (420) farthest in the depth direction, is formed on a shank part (2)-side section of a blade part (3) excluding the axial tip section. The convex-shaped part (30) is divided in the axial direction into an intermediate convex-shaped part (33), which is nearer the tip section, and the base-side convex-shaped part (34), which is nearer the shank part (2) and which has a diameter greater than that of the intermediate convex-shaped part (33). The outer profile of at least a partial section, corresponding to the concave parts (41), of the intermediate convex-shaped part (33) and/or the base-side convex-shaped part (34), is parallel to the rotation axis (10) in the axial direction. A shifting part (35, 36) is formed in a section between the intermediate convex-shaped part (33) and the base-side convex-shaped part (34) and/or a section between the base-side convex-shaped part (34) and the shank part (2), the diameter of the shifting part (35, 36) being greater than that of the portion of the convex-shaped part (30) located on the axial tip side of the section in which the shifting part (35, 36) is formed.

Description

Turbine blade connection groove cutting cutter, turbine blade connection groove cutting method, and turbine blade connection groove manufacturing method

The present invention relates to a cutter used in a method of cutting a connection groove for connecting a turbine blade having a Christmas tree-like cross-sectional shape, a method of cutting a turbine blade connection groove using the cutter, and a method of manufacturing the cutter. It is about.

The connection groove for connecting the turbine blade to the rotating shaft (rotor) of the turbine is formed by alternately repeating a plurality of concave portions and a plurality of convex portions in the depth direction of the work material that is the main body of the turbine. The distance from the central axis facing the depth direction of each concave part and each convex part to the farthest position in the direction perpendicular to the central axis gradually increases from the depth side to the surface side. As a whole, it has a Christmas tree-like cross-sectional shape (see Patent Documents 1 and 2).

Corresponding to the cross-sectional shape of this connection groove, the cutting part of the Christmas cutter that cuts the connection groove is a shape in which convex parts that cut the concave parts and concave parts that cut the convex parts are arranged alternately in the direction of the axis of rotation do. However, since the concave portion has a small cross-sectional area perpendicular to the rotation axis, it tends to be a weak point against the resistance received from the work material when the convex portion is cut, so the possibility of breakage is relatively high.

In order to reduce the possibility of breakage in the concave portion, the connection groove is cut by roughing the area of about 70 to 80% of the entire connection groove volume and the area immediately before the finishing process. Three processes are required: roughing to cut the steel and final finishing. Among these, in the rough roughing process, the amount of cutting with respect to the work material may be larger than in the other two processes, and breakage at the concave portion is likely to occur.

Therefore, in order to reduce the possibility of breakage at the blade portion of the large roughing Christmas cutter, a Christmas cutter in a form in which a concave portion is not formed on the blade portion for large roughing (rough cutting process) may be used. (See Patent Document 3).

As a result of the Christmas cutter blade having a surface passing through a position near the central axis near the smallest diameter point of all the convex portions of the connection groove, the shank portion side is formed in a cylindrical shape and extends toward the tip end side. It is formed into a truncated cone shape with a gradually decreasing diameter (paragraphs 0012 to 0015). In the case where the cylinder and the truncated cone are connected in the axial direction in this way, there is no concave portion having a relatively small diameter in a part of the blade portion in the axial direction, so the possibility of breakage when cutting the connection groove is reduced. To do.

Japanese translation of PCT publication No. 2004-507369 (FIG. 1) Japanese Patent No. 4704495 (paragraphs 0033 to 0056, FIGS. 6 to 12, and 14) International Publication No. 2010/13319 (paragraphs 0012 to 0016, FIG. 5)

However, as disclosed in Patent Document 3, the outline of the cutting edge for large roughing (roughing process) is composed of only a straight line parallel to the rotation axis of the Christmas cutter and a straight line that is continuous with this straight line and not parallel to the rotation axis. In this case, the axial section of the convex portion (narrow portion 11 to 13) of the connecting groove cannot be cut along the surface shape of the convex portion. In other words, the upper and lower portions other than the arc-shaped portion with the smallest diameter of the connection groove are cut because the convex section can only be cut into a cylindrical shape passing through the portion with the smallest diameter on the surface (inner peripheral surface). I can't do it.

As a result, the diameter-reduced portions 41 to 43 having a shape like the concave portion described above must be formed in the section corresponding to the convex portion of the Christmas cutter for the roughing process (mid-finishing process) which is the next process of the roughing process. (Paragraph 0018, FIG. 7). Accordingly, the cutting amount of the upper and lower portions of the convex portion by the reduced diameter portions 41 to 43 is large, and the resistance at the time of cutting of the roughing Christmas cutter is increased, so that the possibility of breakage at the reduced diameter portion may increase. .

In view of the above background, the present invention proposes a cutter for large rough machining that reduces the possibility of breakage due to the formation of a concave portion in a Christmas cutter for rough machining, and a method of cutting a connection groove using the cutter. It is.

The cutter for cutting a turbine blade connection groove according to claim 1 is formed by alternately and repeatedly forming a plurality of concave portions and a plurality of convex portions in the depth direction of the work material. The Christmas tree-like cross-sectional shape in which the distance from the central axis facing the depth direction to the farthest position in the direction perpendicular to the central axis gradually increases from the depth side to the surface side in the depth direction. The method of cutting the connection groove for connecting the turbine blades through a large roughing process for performing a rough roughing, a roughing process for subsequent roughing, and a finishing process for subsequent finishing. A rough roughing process, which is used in a rough roughing process and has a cutting edge having a cutting edge in the entire axial direction on the axial front end side of the shank part, which cuts the plurality of recesses and the plurality of protrusions of the connection groove. Is a cutter for
In the section on the shank part side excluding the tip part in the axial direction of the blade part, the concave part other than the concave part on the innermost side in the depth direction and the convex part other than the convex part on the innermost side are cut. A convex part is formed,
This convex part is divided into an intermediate convex part near the tip in the axial direction and an original convex part having a diameter larger than the diameter of the intermediate convex part near the shank part,
The outline of at least a section corresponding to the concave portion of at least one of the intermediate convex portion and the original convex portion is parallel to the axial rotation axis,
At least one section between the intermediate convex section and the original convex section and between the original convex section and the shank section, the axis of the convex section from the one section The transition part which has a diameter more than the diameter of the part located in the direction front end side is formed.

“Cutting the concave portion” in claim 1 means “cutting the work material for forming the concave portion” precisely, and “cutting the convex portion” similarly means “to form the convex portion”. This means “to cut the work material”. “Cutting the connection groove” means “cutting and machining a work material for forming the connection groove”. The same applies to the fifth and subsequent claims.

As shown in FIG. 1, the blade portion 3 indicates a section on the tip end side in the axial direction of the shank portion 2 except for the shank portion 2 held by the machine tool in the large roughing cutter 1. The section on the side of the shank part excluding the tip part (excluding the shank part 2) refers to a section near the shank part 2 excluding the tip part of the entire length of the blade part 3. The “tip portion” here refers to the “concave portion 32” and the “tip convex portion 31” in claim 5. In FIG. 1, the two-dot chain line indicates the surface of the connection groove 4 formed in the depth direction in the work material 5 after finishing. “Axial tip end side (axial tip end side) of the shank portion 2” refers to the end portion of the blade portion 3 on the opposite side of the shank portion 2 from the full length of the large roughing cutter 1.

As shown in FIGS. 3 and 5, the section excluding the tip portion cuts the concave portions 41 other than the innermost concave portion 410 and the convex portions 42 other than the innermost convex portion 420 in the depth direction of the connection groove 4. This is a convex portion 30. Therefore, in claim 1, the form of the portion (section) that cuts the deepest concave portion 410 and the deepest convex portion 420 of the connecting groove 4, which is the axial tip portion, is not limited. Further, the cutting area of the innermost concave portion 410 and the innermost convex portion 420 (the workpiece 5 for forming the cutting portion 5) by the tip portion of the blade portion 3 is not questioned. The convex portion 30 indicates a section from the intermediate convex portion 33 to the original side transition portion 36 as shown in FIG.

As shown in the figure, when the tip in the axial direction of the blade portion 3 of the rough roughing cutter 1 cuts the innermost concave portion 410 and the innermost convex portion 420 of the connecting groove 4, FIG. As shown in the figure, a concave portion 32 is formed which is continuous with the tip end side in the axial direction of the convex portion 30 and cuts the deepest convex portion 420 (Claim 5). Moreover, the front-end | tip convex part 31 which continues the axial direction front end side of the concave part 32 and cuts the innermost recessed part 410 is formed (Claim 5). In this case, the tip convex portion 31 cuts the workpiece 5 for forming the innermost concave portion 410 of the connection groove 4, and the concave portion 32 forms the innermost convex portion 420. The material 5 is cut.

In claim 5, the concave portion 32 formed at the distal end portion of the blade portion 3 cuts the deepest convex portion 420 (work material 5 for formation) of the connection groove 4, thereby cutting the rough roughing cutter 1. Then, the blade portion 61 of the roughing Christmas cutter 6 is released from the need to cut the innermost convex portion 420. Further, as will be described later, the convex portions 42 other than the deepest convex portion 420 are also cut by the transition portion (at least one of the intermediate transition portion 35 and the original transition portion 36) of the large roughing cutter 1. It is not necessary to form a cutting edge on at least a part of the surface of at least a part of the concave part (63, 65, 67) corresponding to the convex part 42 of the blade part 61 of the Christmas cutter 6 (claim 8). In this case, a cutting edge is not formed in at least a part of the concave portions (63, 65, 67) of the roughing Christmas cutter 6, so that the cutting is perpendicular to the rotation axis 60 (axial direction) of the roughing Christmas cutter 6. The possibility of breakage due to the concave portions (63, 65, 67) being the smallest area cutting the convex portion 42 is reduced.

According to the fifth aspect of the present invention, the tip convex portion 31 that cuts the innermost recess 410 of the connection groove 4 is formed so that the rough roughing cutter 1 cuts at least a part of the innermost recess 410. be able to. As a result, it is possible to reduce the cutting area by the convex portion (tip-side convex portion 62) at the tip end in the axial direction of the roughing Christmas cutter 6, and therefore the tip-side convex portion 62 of the roughing Christmas cutter 6 can be reduced. There is also an advantage that the burden of cutting is reduced. The torsional moment about the rotation axis 60 is reduced when the distal-side convex portion 62 cuts the innermost concave portion 410 by reducing the burden at the time of cutting the distal-side convex portion 62 of the roughing Christmas cutter 6. The possibility that the concave portion (tip-side concave portion 63) having the smallest cross-sectional area adjacent to the tip-side convex portion 62, which is a location susceptible to the influence of the above, receives a torsional moment and breaks is also reduced.

Since the large roughing cutter 1, the roughing Christmas cutter 6, and the finishing Christmas cutter described later may have a chip discharge groove 3 b as described later, they are orthogonal to the rotary shafts 10 and 60. The cross-sectional area is not necessarily circular. Since the original shape of each cutter is a rotary body shape, it is assumed that the cross-sectional area perpendicular to the rotary shafts 10 and 60 of the large roughing cutter 1 and the like is circular, and in the description, for convenience, the rotary shaft 10 The distance from the rotary shafts 10 and 60 to the farthest surface of the rough roughing cutter 1 or the like is called the diameter.

The convex portion 30 of the blade portion 3 of the large roughing cutter 1 is roughly divided into two sections in the axial direction from the tip portion toward the shank portion 2 into an intermediate convex portion 33 and an original convex portion 34. Among these, an intermediate transition part 35 having a diameter equal to or larger than the diameter of the intermediate convex part 33 is formed between the intermediate convex part 33 and the original convex part 34, or the original convex part 34 and the shank part 2 is formed with an original side transition portion 36 having a diameter equal to or larger than the diameter of the original convex portion 34 (claim 1). The intermediate transition portion 35 and the original transition portion 36 may be formed together (claim 2). The convex portion 30 is roughly divided into an intermediate convex portion 33 and an original convex portion 34, but also on the shank portion 2 side of the original convex portion 34 that is a part of the convex portion 30. A blade portion 3 different from the blade portion 3 on which the convex portion 30 is formed may be formed.

“The outline of at least a part of at least one of the intermediate convex portion 33 and the original convex portion 34 is parallel to the axial rotation shaft 10” in claim 1. Only the outline of at least a part of the section 33 is parallel to the rotation axis 10 (axis), and only the outline of at least a section of the original convex part 34 is parallel to the rotation axis 10. In addition to the case, it may be said that at least a part of the outer contour line of the intermediate convex portion 33 and the outer contour line of the original convex portion 34 may be parallel to the rotation axis 10 in some cases. The “outline” refers to the contour of the surface of the convex portion 30 when the blade portion 3 is viewed from the direction perpendicular to the rotation axis 10 as shown in FIG.

The “at least part of the section corresponding to the recess 41” is at least a part of the section in the axial direction of the intermediate convex part 33 and the original convex part 34 corresponding to the recess 41. There may be a case where the entire length corresponds to the concave portion 41 as shown by 1 or the like, or a partial section corresponding to the concave portion 41, such as the original convex portion 34 in FIG. 6- (c).

The transition portion (35, between at least one section between the intermediate convex portion 33 and the original convex portion 34 and between the original convex portion 34 and the shank portion 2 in claim 1. “36) is formed” means that there are the following three cases. That is, the intermediate transition part 35 is formed only between the intermediate convex part 33 and the original convex part 34, and the original transition part 36 is only between the original convex part 34 and the shank part 2. May be formed, and the intermediate transition portion 35 and the original transition portion 36 may be formed together (claim 2).

Further, “a portion located on the tip end side in the axial direction of the convex portion 30 from the one section” refers to a portion on the tip end side in the axial direction from the section in which the transition portions (35, 36) are formed. 1, FIG. 2 and FIG. 6- (b) show an example where the intermediate transition part 35 and the original transition part 36 are formed. FIGS. 6A and 6C show an example in which only the original transition portion 36 is formed and the intermediate transition portion 35 is not formed.

The “transitional portion having a diameter equal to or larger than the diameter of the portion located on the front end side in the axial direction” in claim 1 is formed between the intermediate convex portion 33 and the original convex portion 34 as shown in FIG. The diameter of the intermediate transition portion 35 is equal to or larger than the diameter of the intermediate convex portion 33, and the diameter of the original transition portion 36 is formed between the original convex portion 34 and the shank portion 2. Is greater than or equal to the diameter of the original convex portion 34.

As described above, the “section on the shank portion 2 side excluding the axial front end portion of the blade portion 3” in claim 1 is the recessed portion 41 other than the recessed portion 410 at the innermost side in the depth direction and the protruding portion 420 at the innermost side. It is the convex part 30 which cuts the convex parts 42 other than. This also means that no concave portion (necking) is formed on the entire length of the convex portion 30 excluding the tip portion in the axial direction of the blade portion 3. The tip portion in the axial direction excluding the convex portion 30 of the blade portion 3 cuts the innermost concave portion 410 and the innermost convex portion 420 in the depth direction of the connection groove 4.

The convex part 30 excluding the tip part in the axial direction is divided into an intermediate convex part 33 and an original convex part 34 having a diameter larger than this diameter in the axial direction. Moreover, the diameter of the intermediate transition part 35 in the case of being formed between the intermediate convex part 33 and the original convex part 34 is equal to or larger than the diameter of the portion located on the axial front end side, and the original convex part 34 and When formed between the shank portion 2 and the shank portion 2, the diameter of the original side transition portion 36 is equal to or larger than the diameter of the portion located on the tip side in the axial direction. Also from these things, it can be said that a concave part is not formed in the full length of the convex part 30 except an axial direction front-end | tip part.

The fact that the concave portion is not formed over the entire length of the convex portion 30 means that a portion having a small cross-sectional area in the direction perpendicular to the rotation axis 10 is not formed in the section of the convex portion 30. From this, any particular part of the section of the convex part 30 does not become a weak point at the time of cutting, so that the possibility of breakage in any part of the section of the convex part 30 is reduced. Become.

FIG. 1 shows an example in which the outer contour line of the intermediate convex portion 33 and the outer contour line of the original convex portion 34 are both parallel to the rotating shaft 10, but the outer contour line parallel to the rotating shaft 10 is shown in FIG. There are cases where only the intermediate convex portion 33 is shown as shown in (a) and only the original convex portion 34 is shown as shown in (b) and (c). In the case of the example shown in FIG. 6, the outer contour line of one of the intermediate convex portion 33 and the original convex portion 34 (not parallel to the rotating shaft 10) extends from the tip end side in the axial direction to the shank portion 2 side and is convex. A straight line or a curved line in which the diameter of the portion 30 (distance from the rotating shaft 10) is enlarged is drawn (claim 3).

In addition, the fact that the outline of the section corresponding to at least a part of the concave portions 41 of the convex part 30 is parallel to the rotation axis 10 means that the connection groove of the section corresponding to the outline parallel to the rotation axis 10 after rough roughing That is, the cutting (processing) surface 4 is parallel to the rotation axis 10. Therefore, when measuring the groove accuracy after rough roughing with a dial gauge or the like, the cutting (machined) surface can be measured with higher accuracy than after cutting with a conventional Christmas tree-shaped rough roughing cutter. There are advantages.

In the example shown in FIG. 6, the contour lines that are not parallel to the rotation shaft 10 of the convex portions 33 and 34 are lines that increase in distance from the rotation shaft 10 from the front end side in the axial direction to the shank portion 2 side. The inclined angle is about 10 ° with respect to the rotating shaft 10. If the inclination is such an angle, while the convex portion 30 is formed with at least one of the intermediate transition portion 35 and the original transition portion 36, the above-mentioned “convex portion (constriction on the entire length of the convex portion 30) is formed. ) Is not formed.

In the example shown in FIG. 6A, only the outer contour line of the intermediate convex portion 33 is parallel to the rotary shaft 10 and the outer contour of the section from the section corresponding to the intermediate transition section 35 to the original convex section 34 is obtained. The line is formed as a continuous straight line or a curved line. In the case of the examples shown in (b) and (c), only the outer contour line of the original convex portion 34 is parallel to the rotation axis 10 and the outer contour of the section from the intermediate convex portion 33 to the original convex portion 34 is shown. The line is formed as a continuous straight line or a curved line.

In the case of FIGS. 6- (a) and (c), the intermediate transition portion 35 in the example shown in FIG. 1 does not appear clearly, but an outline that is not parallel to the rotating shaft 10 extends from the axial front end side to the shank portion 2 side. The concave portion (constriction) is not formed on the entire length of the convex portion 30 by drawing a straight line or a curve in which the diameter of the convex portion 30 is enlarged. In the example of FIG. 6- (b), the intermediate transition part 35 and the original transition part 36 appear.

In FIG. 6- (a), the outline that is not parallel to the rotation axis 10 is formed in the section from the portion near the original convex portion 34 of the intermediate convex portion 33 to the original transition portion 36, and (b), (c ) In the section from the axial tip side of the convex part 30 (intermediate convex part 33) to the axial tip side of the original convex part 34 in the example of FIG. 1, or the section to the axial middle part. ing. In the example of (b), a part of the intermediate transition part 35 of the example shown in FIG. 1 is formed. In the examples of (b) and (c), the outline not parallel to the rotating shaft 10 is formed so as to contact the surface of the convex portion 42 corresponding to the intermediate transition portion 35 in the example of FIG. In this case, the surface of the convex portion 42 indicates a surface in a range where the large roughing cutter 1 cuts, leaving the cutting allowance 7 of the finishing Christmas cutter shown in FIG.

The diameter of the original convex part 34 is larger than the diameter of the intermediate convex part 33, and between the intermediate convex part 33 and the original convex part 34, or between the original convex part 34 and the shank part 2, Alternatively, transition portions (intermediate transition portion 35, original side transition portion 36) having a diameter equal to or larger than the diameter of the portion located on the distal end side in the axial direction of the convex portion 30 are formed in both sections. 1). From this, the diameter of the intermediate transition part 35 is gradually or gradually increased from the intermediate convex part 33 side to the original convex part 34. Similarly, the diameter of the original side transition part 36 is gradually or gradually increased from the original side convex part 34 to the shank part 2. The outline of the intermediate transition part 35 or the shape of the outline of the original transition part 36 is basically not questioned (claims 1 to 3).

The “section corresponding to the concave portion 41 of the intermediate convex portion 33 and the original convex portion 34” in claim 1 means that the intermediate convex portion 33 and the original convex portion 34 correspond to the concave portion 41 of the connection groove 4. The intermediate transition portion 35 or the original transition portion 36 is located in a section corresponding to the convex portion 42 of the connection groove 4. On the other hand, the blade portion 3 including the convex portion 30 of the rough roughing cutter 1 has the cutting edge 3a on the entire length in the axial direction as shown in FIG. 7, and therefore, the section of the intermediate transition portion 35 or the original side transition portion 36 is as follows. The convex part 42 (the work material 5 for formation) is cut, and the intermediate convex part 33 and the original convex part 34 cut the concave part 41 (the work material 5 for formation). In the second aspect, the intermediate transition portion 35 and the original transition portion 36 are formed together.

In claim 1, the diameter of the intermediate transition portion 35 in the case of being formed between the intermediate convex portion 33 and the original convex portion 34 is increased from the intermediate convex portion 33 to the original convex portion 34. (Three-dimensional shape). Further, the former side transition part 36 formed between the former convex part 34 and the shank part 2 is formed in a shape (three-dimensional shape) whose diameter increases from the original convex part 34 to the shank part 2. it can. These mean that the surfaces (outline) of the intermediate transition portion 35 and the original transition portion 36 can be easily formed into an elevational shape along the surface of the convex portion 42. It is reasonable that the transition portion 36 cuts a section corresponding to the convex portion 42. The intermediate convex portion 33 and the original convex portion 34 cut a section corresponding to the concave portions 41 and 41 adjacent to the upper and lower sides of the convex portion 42 cut by the intermediate transition portion 35.

On the other hand, the large roughing cutter 1 has a cutting edge on the entire length of the blade portion 3 in the axial direction (Claims 1 and 2), so that the blade portion 3 of the large roughing cutter 1 is cut by rotation around the rotary shaft 10. The connection groove 4 of the material 5 can be cut over the entire length in the depth direction or almost the entire length. As described above, the intermediate transition portion 35 and the original side transition portion 36 cut the convex portion 42 (the work material 5 for formation) in the connection groove 4. By increasing the diameter from the tip end side of the blade part 3 to the shank part 2 side, the intermediate transition part 35 and the original transition part 36 follow the surface shape of the convex part 42 to form the convex part 42. Many work materials 5 can be cut.

Specifically, as shown in FIG. 5, the intermediate transition portion 35 and the original transition portion 36 when formed in the first and second aspects of the present invention are as shown in FIG. 5 at the convex portion 42 of the connection groove 4 located at the corresponding depth. The workpiece 5 can be cut into a convex shape according to the surface shape of the convex portion 42 from the shallow side to the deep side in the depth direction. That is, a large amount of the work material 5 for forming the convex portion 42 can be cut. As a result, since the cutting amount of the work material 5 by the subsequent roughing Christmas cutter 6 at the same convex portion 42 can be reduced, the concave portions (the intermediate concave portion 65 and the shank portion of the roughing Christmas cutter 6). It is possible to reduce the burden on the side concave portion 67).

In FIG. 5, the solid line indicates the outline of the blade portion 3 of the large roughing cutter 1 having the intermediate transition portion 35 and the original transition portion 36, and the broken line indicates the blade portion of the roughing Christmas cutter 6 following the large roughing cutter 1. 61 outlines are shown. As shown here, in the convex portion 42 corresponding to the section of the intermediate transition portion 35, the solid line passes closer to the work material 5 than the broken line, so in the section of the convex portion 42, the work material 5 by the large roughing cutter 1 It can be seen that the cutting amount can be made larger than the cutting amount of the work material 5 by the roughing Christmas cutter 6.

When both the intermediate transition portion 35 and the original transition portion 36 are present (Claim 2), as shown in FIG. 5, both transition portions 35 in the convex portions 42 other than the rearmost convex portion 420 of the connection groove 4, The workpiece 5 can be cut into a convex shape 36 according to the surface shape of the convex portion 42. As a result, the large roughing cutter 1 can cut a large amount of the work material 5 for forming the convex part 42, and the burden of the concave part (the shank part side concave part 67) of the roughing Christmas cutter 6 can be reduced. Can be reduced.

In claim 1, at least one of the intermediate transition portion 35 and the original transition portion 36 can cut many workpieces 5 for forming the convex portions 42. In the second aspect, both the intermediate transition portion 35 and the original transition portion 36 can cut many workpieces 5 for forming the convex portions 42. Accordingly, the cutting edge is formed on at least a part of the concave portions (63, 65, 67) of the roughing Christmas cutter 6 that cuts the workpiece 5 in the roughing step after the large roughing step by the large roughing cutter 1. It is possible to eliminate the need to form (Claim 8).

As shown in FIG. 3B, the roughing Christmas cutter 6 is provided with a concave portion (63, 65, 67) corresponding to the convex portion 42 of the connection groove 4 and having a relatively small cross-sectional area perpendicular to the rotating shaft 60. ), As described above, it is not necessary to form a cutting edge on the concave portion (63, 65, 67), so that the workpiece 5 can be cut at the concave portion (63, 65, 67). It becomes unnecessary. As a result, it is possible to obtain an effect of reducing the possibility of breakage at the concave portions (63, 65, 67) of the roughing Christmas cutter 6.

When the cutting edge is formed in the concave portion (63, 65, 67) of the Christmas cutter 6 for roughing, the concave portion (tip end) on the tip end side in the axial direction, which is a portion having a small cross-sectional area in the direction orthogonal to the rotation shaft 60 The side recess 63) is most likely to break when the workpiece 5 is cut. Therefore, it is particularly effective to not form a cutting edge on at least the surface of the tip side concave portion 63 in order to reduce the possibility of breakage at the tip side concave portion 63 having the highest possibility of breakage.

The intermediate transition portion 35 and the original transition portion 36 of the rough roughing cutter 1 cut many workpieces 5 for forming the convex portions 42 in the connection grooves 4, but correspond to the concave portions 41 of the connection grooves 4. Since the outer contour line of the intermediate convex portion 33 and the original convex portion 34 in the section is parallel to the rotary shaft 10, the blade portion of the large roughing Christmas cutter in Patent Document 2 cuts the blade portion 3 as a whole. The cutting amount (volume) of the groove 4 is reduced.

In the example of the Christmas cutter for large rough machining shown in FIG. 6 of Patent Document 2, as shown in FIG. 4- (a), the concave and convex portions are alternately formed in the axial direction on the blade portion. Since the part is cut so that the part enters the concave part from the convex part of the connecting groove in the radial direction, the concave part can be broken due to the influence (torsional moment) generated in the concave part having a small cross-sectional area when the concave part is cut by the convex part. Hidden. The cutting amount of the cutting edge of the Christmas cutter for large rough machining in Patent Document 2 accounts for about 80% of the cutting amount of the entire connection groove 4.

On the other hand, the intermediate convex portion 33 and the original convex portion 34 of the rough roughing cutter 1 according to claims 1 and 2 are intermediate portions for cutting the convex portion 42 of the connection groove 4 as shown in FIG. The intermediate convex portion 33 and the original convex portion 34 are cut so as to enter the concave portion 41 from the convex portion 42 of the connection groove 4 by not having a shape protruding from the transition portion 35 to the radially outer peripheral side. There is no. That is, a concave portion having a small cross-sectional area perpendicular to the rotation shaft 10 is not formed in the section from the intermediate convex portion 33 to the shank portion 2 as described above.

Therefore, any part of the section from the intermediate convex part 33 to the shank part 2 does not become a weak point at the time of cutting as described above. The possibility of breakage at the part is decreasing. Since the intermediate convex portion 33 and the original convex portion 34 do not protrude radially outward from the intermediate transition portion 35, the cutting amount of the blade portion 3 of the large roughing cutter 1 according to claim 1 or 2 is determined by the connecting groove 4. It remains below about 70% of the total cutting amount.

The cutting edge 61 of the roughing Christmas cutter 6 and the finishing Christmas cutter described later have a Christmas tree shape as shown in FIGS. 3B and 3C, whereas the large roughing cutter 1 of the present invention is used. As described above, the intermediate convex portion 33 and the original convex portion 34 do not have a shape projecting toward the radially outer peripheral side, so that they do not form a Christmas tree, and are simply called cutters.

When the cutting amount of the blade portion 3 of the rough roughing cutter 1 is small, the burden (load) of the large roughing cutter 1 itself when cutting the work material 5 is reduced. As the amount of cutting increases, the burden on the roughing Christmas cutter 6 increases, and the possibility of breakage at the concave portions (63, 65, 67) increases. Therefore, the cutting of the work material 5 at the concave portions (63, 65, 67) of the roughing Christmas cutter 6 is not required, and any portion of the convex portion 30 of the large roughing cutter 1 is used. In reducing the possibility of breakage, the cutting amount of the blade portion 3 of the large roughing cutter 1 is in the range of about 60% (lower limit) to about 70% (upper limit) of the entire cutting amount of the connection groove 4. Is appropriate.

As a shape for “the transition part (the intermediate transition part 35 and the original transition part 36) cut the workpiece 5 into a convex shape according to the surface shape of the convex part 42”, at least one of the transition parts (35 36), the contour line of at least a part of the section corresponding to the convex portion 42 runs along the surface shape of the convex portion 42, and extends from the tip end side in the axial direction to the shank portion 2 side. It is appropriate to draw a curve in which the distance from 10) gradually increases (claim 4). The “curve in which the diameter of the convex portion 30 gradually increases” is a curve in which the distance from the rotary shaft 10 of the rough roughing cutter 1 to the surface of the convex portion 30 farthest in the direction perpendicular to the rotary shaft 10 gradually increases. In other words.

As shown in FIG. 5, the curve of the transition portion (intermediate transition portion 35 and original side transition portion 36) is a cross section of the connection groove 4 and the blade portion 3 of the rough roughing cutter 1 parallel to the central axis O (rotary shaft 10). 4 is a curve along the surface of at least a part of the convex portion 42 of the connection groove 4 when viewed at (when viewed in a direction perpendicular to the central axis O). In the example shown in FIGS. 6A to 6C, the outline of the original transition portion 36 is a curve along the surface of the convex portion 42.

At least one of the outlines of at least one of the transition portions (35, 36) draws a curve along the surface of the convex portion 42, so that the intermediate transition portion 35 and the original side transition portion 36 (of the At least one of the cutting blades) can cut many workpieces 5 for forming the convex portions 42 corresponding thereto, and the concave portions (63, 65, It becomes possible to reduce the cutting amount of the work material 5 in 67).

Thus, in claim 4, as shown in FIG. 5, at least one of the intermediate transition portion 35 and the original transition portion 36 is in the depth direction (center axis O direction) in the section of the convex portion 42 of the connection groove 4. Since a large range of the work material 5 can be cut, the workpiece for forming the convex portion 42 at the concave portions (63, 65, 67) of the roughing Christmas cutter 6 used after the rough roughing is used. Cutting of the cutting material 5 can be completely or almost completely unnecessary.

The requirement of claim 4 is a specific example of the requirement of claim 1, “the transition portions (35, 36) having a diameter equal to or larger than the diameter of the portion located on the tip end side in the axial direction of the convex portion 30”. Yes, since the requirement of claim 1 is also inherited by claim 2, the cutting of the work material 5 for forming the convex portion 42 at the concave portion (63, 65, 67) of the roughing Christmas cutter 6 becomes unnecessary. The possible advantages are derived from the requirements of claims 1 and 2.

The rotary shaft 10 of the rough roughing cutter 1 and the rotary shaft 60 of the roughing Christmas cutter 6 are overlapped, and the outline of the blade 3 of the large roughing cutter 1 and the outline of the blade 61 of the roughing Christmas cutter 6 are obtained. In the overlapped left side of FIG. 5, let A be the intersection with the plane perpendicular to the rotation axis 10 near the shank 2 of the blades 3 and 61. Further, the intersections of the outline of the large roughing cutter 1 and the outline of the roughing Christmas cutter 6 are denoted by B to G from the shallow side to the deep side of the connecting groove 4 in the depth direction. As described above, in the drawing, the solid line indicates the outline of the blade portion 3 of the large roughing cutter 1, and the broken line indicates the outline of the blade portion 61 of the roughing Christmas cutter 6.

In the drawings including FIG. 5, a concave portion 32 is formed which is continuous with the distal end side in the axial direction of the convex portion 30 of the rough roughing cutter 1 and cuts the deepest convex portion 420. An example is shown in which the tip convex portion 31 that is continuous with the tip end and cuts the innermost recess 410 is formed (Claim 5). In the drawing, in particular, the tip convex portion 31 cuts a part of the deepest concave portion 410 (working material 5 for formation), and the convex of the tip portion in the axial direction of the blade portion 61 of the Christmas cutter 6 for roughing. The example in which a shape part (front-end | tip convex part 62) cuts an area | region (workpiece 5) more than the front-end | tip convex part 31 is shown.

When the tip convex portion 31 is formed on the tip end side in the axial direction of the convex portion 30 (Claim 5), the outline (surface) of the tip convex portion 31 follows the surface shape of the concave portion 410 corresponding thereto. Alternatively, it can be formed in a close shape or a cylindrical shape. However, as shown in FIG. 1 and the like, the tip convex portion 31 is formed from the shank portion 2 side to the tip end side in the axial direction and formed into a shape with a reduced diameter (Claim 6). The resistance that the convex portion 30 receives from the work material 5 when cutting the concave portion 410 on the back side can be suppressed, so that the concave portion 32 adjacent to the shank portion 2 side of the tip convex portion 31 has the smallest diameter portion. The possibility of breakage can be reduced.

In the case of claim 6, the tip convex portion 31 is formed in a truncated cone shape or the like, so that the cutting range of the concave portion 41 is suppressed as compared with the case of the columnar shape, and from the rotating shaft 10 to the surface of the tip convex portion 31. Since the distance is reduced, the resistance that the concave portion 32 receives from the work material 5 is reduced. As a result, the torsional moment that acts on the concave portion 32 adjacent to the shank portion 2 side of the tip convex portion 31 when the concave portion 410 is cut by the tip convex portion 31 can be reduced, so that the possibility of breakage of the concave portion 32 is reduced. Can be made.

5, in the sections AB, CD, and EF corresponding to the convex portions 42 of the connection groove 4, the surface (outline) of the rough roughing cutter 1 is the surface (outer shape) of the roughing Christmas cutter 6 as described above. The blade 3 of the large roughing cutter 1 cuts most of the work material 5 for forming the convex portion 42 because it is located farther from the central axis O of the connection groove 4 than the line. Accordingly, the concave parts (63, 65, 67) of the roughing Christmas cutter 6 need not or hardly cut the work material 5 for forming the convex part 42. The concave part (63, 65, 67) needs no or almost no cutting edge (Claim 8).

In the sections BC, DE and FG corresponding to the recess 41 of the connection groove 4, the surface (outline) of the roughing Christmas cutter 6 is the central axis of the connection groove 4 from the surface (outline) of the large roughing cutter 1. Located far from O. Accordingly, in these sections, since the convex portions (62, 64, 66) of the roughing Christmas cutter 6 cut most of the work material 5 for forming the concave portions 41, the convex portions of the roughing Christmas cutter 6 are formed. A cutting edge is formed on the surface of (62, 64, 66).

The intersections A and B can be said as boundary points as a guideline for defining (specifying) the axial range of the original side transition portion 36 of the large roughing cutter 1, and the concave portion on the shank portion side of the roughing Christmas cutter 6. It can also be said to be a boundary point that divides the range in the axial direction of the (shank portion-side concave portion 67). Similarly, the intersections C and D can also be said to be boundary points that define the axial range of the intermediate transition portion 35 of the large roughing cutter 1, and a concave portion (intermediate concave portion 65 of the axially intermediate portion of the roughing Christmas cutter 6. It can be said that it is a boundary point that divides the range in the axial direction. The intersections E and F can also be regarded as boundary points that delimit the range of the concave portion 32 of the large roughing cutter 1, and delimit the range of the concave portion (tip-side concave portion 62) on the tip end side in the axial direction of the roughing Christmas cutter 6. It can be said that it is a boundary point.

Further, the intersection points B and C can also be said as boundary points as a guideline for defining the axial range of the original convex portion 34 of the large roughing cutter 1, and the convex portion (shank) on the shank portion side of the roughing Christmas cutter 6. It can also be said that the boundary point demarcates the axial range of the part-side convex part 66). The intersections D and E can also be said as boundary points as a guideline for defining the range in the axial direction of the intermediate convex portion 33 of the large roughing cutter 1, and the convex portion (intermediate portion) of the intermediate axial portion of the roughing Christmas cutter 6. It can also be said to be a boundary point that defines the axial range of the convex portion 64).

The intersections F and G can also be said as boundary points as a guideline for defining the axial range of the tip convex portion 31 of the large roughing cutter 1, and the convex portion (tip side) of the axial tip portion of the roughing Christmas cutter 6. It can also be said to be a boundary point that defines the axial range of the convex portion 62). The intersection point F is also a boundary point between the concave portion 32 and the tip convex portion 31 of the large roughing cutter 1, and the concave portion on the tip side (tip side concave portion 63) and the convex shape on the tip side of the Christmas cutter 6 for roughing. It is also a boundary point of the portion (tip-side convex portion 62). The intersection point G corresponds to the position of the bottom of the innermost recess 410 of the connection groove 4. The drawing shows an example of the cross-sectional shape of the connection groove 4 when three concave portions 41 and three convex portions 42 are formed, but there may be four or more concave portions 41 and convex portions 42 formed.

As described above, in the first to sixth aspects, the cutting of the work material 5 for forming the convex portions 42 in the plurality of concave portions (63, 65, 67) of the roughing Christmas cutter 6 is unnecessary or reduced. (Claim 8), the diameter of the concave portion (63, 65, 67) of the roughing Christmas cutter 6 is made to correspond to the concave portion 32 and the intermediate transition portion 35 of the large roughing cutter 1. The diameter of the transition portion 36 can be made smaller. As a result, the concave portions (63, 65, 67) of the roughing Christmas cutter 6 are formed on the surface of the convex portion 42 after the concave portion 32, the intermediate transition portion 35, and the original side transition portion 36 of the large roughing cutter 1 are cut. It is possible to eliminate the need for contact.

“The diameter of the concave portion (63, 65, 67) of the roughing Christmas cutter 6 is smaller than the diameter of the concave portion 32 of the large roughing cutter 1” means that the rotational shaft 60 of the roughing Christmas cutter 6 is The distance to the surface of the concave portion (63, 65, 67) in the direction perpendicular to the rotary shaft 60 is also smaller than the distance from the rotary shaft 10 to the surface of the convex portion 42 cut in the large roughing process. .

In the cutting method of the turbine blade connection groove according to claim 7, a plurality of concave portions 41 and a plurality of convex portions 42 are alternately and repeatedly formed in the depth direction of the work material 5. The Christmas tree in which the distance from the central axis O facing the depth direction of the convex portion 42 to the position farthest in the direction perpendicular to the central axis O gradually increases from the depth side to the surface side in the depth direction. Is a method of cutting a connection groove 4 for connecting turbine blades having a cross-sectional shape, a large roughing process for roughing, followed by a roughing process for roughing, followed by finishing. The connecting groove 4 is cut through a finishing process to be performed, and in the large roughing process, the concave portion 41 of the connecting groove 4 is used using the large roughing cutter 1 according to any one of claims 1 to 6. And cutting the convex part 42 And wherein the Rukoto.

In this method, the work material 5 for forming the connection groove 4 is cut using the large roughing cutter 1 according to any one of claims 1 to 6, and thus the method according to claim 1 to 6. The advantages of the present invention can be taken over.

The cutting method of the turbine blade connection groove according to claim 8 is the connecting groove 4 in the axial direction of the blade portion 61 in the roughing step of the cutting method of the turbine blade connection groove according to claim 7. Convex portions (62, 64, 66) and concave portions (63, 65, 67) corresponding to the plurality of concave portions 41 and the plurality of convex portions 42 are alternately formed, and the convex portions (62, 64). 66) is formed on the surface of the connecting groove 4 and a cutting edge is formed on at least a part of the surface of at least a part of the concave portions (63, 65, 67). The recess 41 and the projection 42 of the connection groove 4 are cut using a rough cutting Christmas cutter 6.

In the large roughing process, at least one of the intermediate transition portion 35 and the original transition portion 36 of the large roughing cutter 1 can cut the convex portion 42 (workpiece 5 for formation) of the connection groove 4. As described above, the concave portion of the roughing Christmas cutter 6 corresponding to the section of the intermediate transition portion 35 of the large roughing cutter 1 in which at least the convex portion 42 has been cut (the intermediate concave portion 65 and the shank portion side concave portion 67). At least one of them is freed from the need to cut the convex portion 42. Therefore, it is not necessary to form a cutting edge on at least a part of the surface of the concave portion (at least one of the intermediate concave portion 65 and the shank-side concave portion 67) of the roughing Christmas cutter 6.

In addition to the intermediate transition portion 35 or the intermediate transition portion 35 and the original transition portion 36, the concave portion 32 that cuts the deepest convex portion 420 in the depth direction is formed in the large roughing cutter 1 (claim) 5), the concave portion (tip-side concave portion 63) of the roughing Christmas cutter 6 corresponding to the section of the concave portion 32 is released from the need to cut the convex portion. Therefore, it is not necessary to form a cutting edge on at least a part of the surface of the concave portion (tip-side concave portion 63) of the roughing Christmas cutter 6.

The “at least part of the concave portion” in claim 8 is an intermediate concave portion of the roughing Christmas cutter 6 corresponding to at least one of the intermediate transition portion 35 and the original transition portion 36 of the large roughing cutter 1. 65 and at least any one of the shank part side recessed parts 67 are pointed out. When the concave portion 32 is formed in the large roughing cutter 1 (Claim 5), the concave portion (tip-side concave portion 63) of the roughing Christmas cutter 6 corresponding to the concave portion 32 is also included.

As shown in FIG. 3B, the cutting edge 61 of the roughing Christmas cutter 6 corresponds to the plurality of concave portions 41 and the plurality of convex portions 42 of the connection groove 4 in the axial direction, and an axial rotation shaft 60. To the farthest position in the direction perpendicular to the rotation axis 60, the convex part (62, 64, 66) and the concave part (63, 65, 67) are alternately formed. A cutting edge is formed on the surface of the convex portion (62, 64, 66) to cut the concave portion 41 (work material 5 for formation) of the connection groove 4 (claim 8). As shown in FIG. 5, the distance from the rotary shaft 60 (in the direction perpendicular to the rotary shaft 60) to the surface of the concave portions (63, 65, 67) of the roughing christmas cutter 6 where no cutting edge is formed is large rough machining. The cutting edge is not formed on at least a part of the surface of the concave portion (63, 65, 67), which is smaller than the distance from the rotary shaft 10 to the surface of the convex portion 42 of the connection groove 4 to be cut in the process ( Claim 8).

In the method for manufacturing a turbine blade connection groove according to claim 9, a plurality of concave portions 41 and a plurality of convex portions 42 are alternately and repeatedly formed in the depth direction of the work material 5, and the concave portions 41 and the convex portions are formed. The distance from the central axis O facing the depth direction of the portion 42 to the position farthest in the direction perpendicular to the central axis O gradually increases from the depth side to the surface side in the depth direction. Is a method of manufacturing a connecting groove 4 for connecting turbine blades having a cross-sectional shape, a large roughing process for roughing, followed by a roughing process for roughing, and then finishing for finishing. The connection groove 4 is manufactured through a processing step,
In the large roughing step, the concave portion and the convex portion of the connection groove are cut using the rough roughing cutter 1 according to any one of claims 1 to 6.

Claim 9 is an invention in which the cutting method of claim 7 is expressed as a method of manufacturing a connection groove, and is substantially the same as the method of claim 7.

A convex shape that cuts the recesses other than the deepest concave part in the depth direction and the convex parts other than the deepest convex part in the section on the shank part side excluding the axial tip of the blade part of the rough roughing cutter The convex portion is divided into an intermediate convex portion closer to the tip portion in the axial direction and an original convex portion closer to the shank portion and having a diameter larger than the diameter of the intermediate convex portion. In addition, in at least one section between the intermediate convex section and the original convex section and between the original convex section and the shank section, it is located on the axial front end side of the convex section from that section. In order to form a transition portion having a diameter equal to or larger than the diameter of the portion, the transition portion can be formed in a shape whose diameter increases from the axial front end side to the shank portion side.

As a result, the surface of the transition portion can be formed into an elevational shape along the surface of the convex portion of the connection groove, and the transition portion follows the surface shape of the convex portion of the connection groove located at the corresponding depth. Since the work material can be cut into a convex shape, many work materials for forming the convex portion can be cut.

Therefore, it is possible to avoid forming a cutting edge on at least a part of the concave portion of the roughing Christmas cutter that cuts the work material in the roughing step after the large roughing step by the large roughing cutter. Cutting of the work material can be eliminated or reduced. As a result, the roughing Christmas cutter is formed with a concave portion corresponding to the convex portion of the connection groove and having a relatively small cross-sectional area perpendicular to the rotation axis, but the roughing Christmas cutter is not broken at the concave portion. The possibility can be reduced.

It is the side (elevation) figure which showed the example of formation of the blade part of the cutter for large rough machining in which the front-end | tip convex part and the concave part were formed in the axial direction front end side. It is sectional drawing of the direction perpendicular | vertical to the connection groove center axis | shaft which showed the relationship between the surface of the connection groove | channel finally formed after a finishing process, and the surface of the blade part of the cutter for large rough machining. (A) is sectional drawing which showed the relationship between the outline of the cutter for large roughing, and the surface of the connection groove finally formed, (b) is the outline of the Christmas cutter for roughing, and the surface of the connection groove Sectional drawing showing the relationship, (c) is a sectional view showing the shape of the final connection groove after cutting the work material by the Christmas cutter for finishing. (A) to (c) are sectional views (FIG. 6 of Patent Document 2) perpendicular to the central axis showing the work procedure of Patent Document 2 to be compared with FIG. 3, and (a) to (c) ) Corresponds to (a) to (c) of FIG. FIG. 4 is an enlarged view of FIG. 3B showing the relationship between the outlines of the large roughing cutter and the roughing Christmas cutter shown in FIG. 3. (A)-(c) is an elevational view showing an example of forming a blade portion of a cutter for large roughing having a contour line that is not parallel to the rotation axis in a part of the convex portion. It is the perspective view which showed the manufacture example of the cutter for large rough machining in which the chip | tip discharge groove | channel which follows the axial direction of a blade part was formed.

FIG. 1 shows a method of cutting a connection groove 4 for connecting turbine blades formed in a shape in which a plurality of concave portions 41 and a plurality of convex portions 42 are alternately arranged, as shown in FIG. 6 shows an example of manufacturing the large roughing cutter 1 used in a large roughing process for roughing the connection groove 4. The rough roughing cutter 1 cuts a plurality of concave portions 41 and a plurality of convex portions 42 of the connecting groove 4 on the axial front end side of the shank portion 2 held by the machine tool, and has a cutting edge 3a in the entire axial length. It has a shape in which the blade portion 3 is integrally formed.

As shown in FIGS. 3A to 3C, the connecting groove 4 has a large roughing process using the large roughing cutter 1 as shown in FIGS. 3A to 3C, and a roughing process using the roughing Christmas cutter 6 shown in FIG. It is formed through a finishing process using a Christmas cutter for finishing. Although the Christmas cutter for finishing is not shown, it has an elevation shape along the surface shape of the connecting groove 4 after finishing shown in FIG. FIG. 2 shows the relationship between the connection groove 4 formed after the finishing process and the outline of the rough roughing cutter 1. As shown in FIG. 3- (a), the concavity 41 and the convex portion 42 do not appear in the connection groove 4 after the large roughing process is completed. Therefore, the concave portion 41 and the convex portion 42 are mainly shown in FIG. The concave and convex portions of the connection groove 4 formed after the roughing process or after the finishing process shown in FIG.

As shown in FIG. 7, the cutting edge 3a of the blade portion 3 is formed in a continuous groove shape in the axial direction while having a twist angle with respect to the rotary shaft 10 from the axial tip of the blade portion 3 to the shank portion 2. Is formed as a convex ridge line or the like on the edge on the radially outer side of the surface (rake surface) on the rear side in the rotation direction of the chip discharge groove 3b. “Axial tip of the blade 3” refers to the end opposite to the shank 2.

As shown in FIG. 3C, the connection grooves 4 finally formed through the finishing process are arranged by alternately arranging a plurality of concave portions 41 and a plurality of convex portions 42 in the depth direction of the work material 5. To form. The distance from the central axis O facing the depth direction to the position farthest in the direction perpendicular to the central axis O of each concave portion 41 and each convex portion 42 gradually increases from the depth side to the surface side in the depth direction. It has a tree-like cross-sectional shape.

The section on the shank portion 2 side excluding the tip end portion in the axial direction of the blade portion 3 includes recesses 41 other than the recesses 410 at the innermost side in the depth direction of the connection grooves 4 as shown in FIGS. The convex part 30 which cuts the convex parts 42 other than the innermost convex part 420 is formed. As shown in FIG. 1, the convex portion 30 includes an intermediate convex portion 33 closer to the tip end in the axial direction, and an original convex portion 34 having a diameter larger than the diameter of the intermediate convex portion 33 near the shank portion 2. It is roughly divided into

When cutting the deepest convex portion 420 and the deepest concave portion 410 of the connection groove 4 at the portion on the tip side in the axial direction from the convex portion 30, as shown in FIGS. A concave portion 32 for cutting the innermost convex portion 420 is formed continuously in the axial direction of the convex portion 30 at the tip end side in the axial direction of 30. Further, a tip convex portion 31 that is continuous with the tip end side in the axial direction of the concave portion 32 and cuts the innermost concave portion 410 is formed. The shapes of the concave portion 32 and the tip convex portion 31 are not limited, but in the drawing, the outer shape line is the axis of the concave portion 32 and the tip convex portion 31 as in the intermediate transition portion 35 or the original transition portion 36 described later. A straight line or a curved line is formed in which the diameter of the convex portion 30 (distance from the rotating shaft 10) extends from the direction tip side to the shank portion 2 side.

At least one of the intermediate convex portion 33 and the original convex portion 34 of the convex portion 30 has an outline of at least a section corresponding to the concave portion 41 in parallel with the axial rotation shaft 10. At least one section between the intermediate convex section 33 and the original convex section 34 and between the original convex section 34 and the shank section 2, the tip of the convex section 30 in the axial direction from that section Transition portions (intermediate transition portion 35, former-side transition portion 36) having a diameter equal to or larger than the diameter of the portion located on the side are formed.

1 to 3 and 5, an intermediate transition portion 35 having a diameter equal to or larger than the diameter of the intermediate convex portion 33 is formed between the intermediate convex portion 33 and the original convex portion 34. Further, an original side transition portion 36 having a diameter equal to or larger than the diameter of the original convex portion 34 is formed between the original convex portion 34 and the shank portion 2. The fact that at least a part of the outline of the intermediate convex part 33 and the original convex part 34 is parallel to the rotation axis 10 means that the surface shape of at least a part of the intermediate convex part 33 and the original convex part 34 is It is also cylindrical. 1, 2, and 6, the portion of the convex portion 30 divided in the axial direction, for example, between the intermediate convex portion 33 and the intermediate transition portion 35, the intermediate transition portion 35 and the original convex portion 34, Although the boundary line is indicated by a thin line between the lines, the boundary line may not be clearly displayed.

The distance from the central axis O in the direction perpendicular to the central axis O of the concave portion 41 and the convex portion 42 of the connecting groove 4 gradually increases toward the surface side of the work material 5, and the intermediate convex portion 33, The following can be said because at least a part of the axial direction of the original convex portion 34 is cylindrical. That is, as shown in FIGS. 3A and 5, for example, a portion of the intermediate convex portion 33 near the shank portion 2 is inscribed in the surface of a cutting allowance 7 of a finishing Christmas cutter to be described later on the convex portion 42. However, the portion near the tip of the intermediate convex portion 33 can be inscribed in the surface of the cutting allowance 7 on the surface (upward surface) facing the shank portion 2 side in the concave portion 41 on that side. This means that the portion near the tip of the intermediate convex portion 33 and the portion near the shank portion 2 can be easily formed in a shape along the surface of the convex portion 42 on each side, and the original convex portion 34 is formed. The same can be said.

The cutting allowance 7 of the finishing Christmas cutter is the surface of the connecting groove 4 after the workpiece 5 is cut by the large roughing cutter 1 and the roughing Christmas cutter 6 as shown in FIGS. , And refers to the thickness when a finishing Christmas cutter (not shown) cuts a certain depth in the radial direction from this surface.

The intermediate convex portion 33 and the original convex portion 34 cut the concave portion 41 other than the deepest concave portion 410 of the connection groove 4. In the example shown in FIGS. 1 and 5, the section corresponding to the concave portion 41 is cut. Since the contour line is parallel to the rotation axis 10, the intermediate convex portion 33 and the original convex portion 34 have a cutting allowance 8 cut by the roughing Christmas cutter 6 in the concave portion 41 as shown by a broken line in FIG. The remaining part of the recess 41 near the rotating shaft 10 is cut. In FIG. 5, in the section of the recess 41, a range surrounded by a solid line and a broken line is a cutting allowance 8 cut by the roughing Christmas cutter 6. As shown in FIG. 5, the cutting allowance 8 of the rough machining Christmas cutter 6 refers to the surface of the connection groove 4 after the workpiece 5 is cut by the large rough machining cutter 1, from which the rough machining Christmas cutter 6 It refers to the thickness when cutting a certain depth in the radial direction.

The intermediate transition part 35 is formed in a shape (three-dimensional shape) whose diameter gradually increases from the intermediate convex part 33 to the original convex part 34 in the axial direction of the blade part 3 as shown in FIG. The transition part 36 is also formed in a shape (three-dimensional shape) whose diameter gradually increases from the original convex part 34 to the shank part 2 side. 1 and 2, at least a part of the outline of the intermediate transition portion 35 is drawn into a straight line in which the diameter of the convex portion 30 gradually increases toward the original convex portion 34, and the surface is formed in a truncated cone shape. Yes. Further, at least a part of the outline of the original side transition part 36 draws a curve whose diameter gradually increases toward the shank part 2, but the shape of these outlines is arbitrary.

However, in the case of drawing a curve whose diameter gradually increases from the distal end side of the blade part 3 to the shank part 2 side like the original side transition part 36 shown in FIG. 1 and FIG. A portion near the shank portion 2 and a portion near the tip of the portion 34 are inscribed in the surface of the cutting allowance 7, and the surface of the original side transition portion 36 is brought close to the surface of the convex portion 42 corresponding to the section. be able to. For this reason, it is reasonable to draw both outer contour lines of the intermediate transition part 35 and the original transition part 36.

Of the connecting groove 4, most of the convex portion 42 (work material 5 for forming), that is, the portion excluding the cutting allowance 7 cut by the finishing Christmas cutter is the intermediate transition portion 35 of the large roughing cutter 1. The former side transition part 36 and the concave part 32 when formed are cut. From this, the roughing Christmas cutter 6 does not necessarily need to cut the convex portion 42, and therefore, at least part of the surface of the section (concave portion) corresponding to the convex portion 42 of the roughing Christmas cutter 6 is cut. The blade need not be formed.

The curves drawn by the outer contour lines of the intermediate transition portion 35 and the original transition portion 36 correspond to the range of the connecting groove 4 to be cut by the blade portion 3 of the large roughing cutter 1 as shown by the solid line in FIG. It is appropriate to draw a curve along the shape along the surface or through the position close to the central axis O side from the surface of the convex portion 42 by the cutting allowance of the Christmas cutter for finishing processing for 7 minutes. Since the cutting edge 3 of the rough roughing cutter 1 has a cutting edge 3a along the entire length in the axial direction as shown in FIG. 7, the range indicated by the solid line in FIG. To do. A blade portion 61 of a roughing Christmas cutter 6 described later cuts a range indicated by a broken line in FIG.

In this relationship, in the range of the convex portion 30 of the large roughing cutter 1, the intermediate transition portion 35 and the original transition portion 36 mainly cut the convex portion 42 of the connection groove 4, and the blade portion of the roughing Christmas cutter 6. 61 cuts the concave portion 41 without cutting the convex portion 42 in the range of the convex portion 30. Therefore, the cutting edge of the roughing Christmas cutter 6 is formed on the surface of the intermediate convex part 64 and the shank part convex part 66 which are sections corresponding to the concave part 41 as shown in FIG. Is not formed on at least a part of the surface of the intermediate concave portion 65 and the shank portion-side concave portion 67 which are sections corresponding to.

As described above, when the concave portion 32 and the tip convex portion 31 are formed on the tip end side in the axial direction of the convex portion 30 of the rough roughing cutter 1, the concave portion 32 is the convex portion 420 at the innermost side of the connection groove 4. The tip convex portion 31 cuts the deepest concave portion 410. The concave portion 32 cuts the convex portion 42 (work material 5 for forming) of the connection groove 4, similarly to the intermediate transition portion 35 and the original transition portion 36. However, in the same way as the intermediate convex portion 33 and the original convex portion 34, the tip convex portion 31 has a cutting allowance 8 at which the roughing Christmas cutter 6 cuts the range of the innermost concave portion 410 close to the rotation axis 10. Cut and leave.

In the section corresponding to the tip end side in the axial direction of the convex portion 30 of the large roughing cutter 1, the tip end side is continuous with the tip end side in the axial direction of the intermediate convex portion 64 of the blade portion 61 of the Christmas cutter 6 for roughing. A concave portion 63 is formed, and a distal-side convex portion 62 is formed continuously to the distal end side in the axial direction of the distal-side concave portion 63. The distal-side convex portion 62 cuts the innermost concave portion 410, but the distal-side concave portion 63 does not cut the innermost-side convex portion 420 as described above. It is formed on the surface and is not formed on at least a part of the surface of the tip-side concave portion 63.

The tip-side convex portion 62 of the roughing Christmas cutter 6 is a cutting allowance 8 of the roughing Christmas cutter 6 left after the tip-like convex portion 31 of the large roughing cutter 1 is cut in the innermost concave portion 410. Cut the minutes.

The shape (outline) of the tip convex portion 31 of the rough roughing cutter 1 may be formed in the same cylindrical shape as the intermediate convex portion 33 and the original convex portion 34, but in the drawing, the tip convex portion The diameter decreases from the shank portion 2 side to the tip so that the possibility of breakage of the smallest diameter portion of the concave portion 32 adjacent to the shank portion 2 side is reduced when the innermost concave portion 410 is cut by 31. It is formed in a truncated cone shape or a rotating body shape similar to it. By forming the tip convex portion 31 in a truncated cone shape or the like, the cutting range of the work material 5 in the concave portion 41 is suppressed as compared with the case of a cylindrical shape, and the distance from the rotary shaft 10 to the surface of the tip convex portion 31 is reduced. Therefore, the possibility of breakage of the concave portion 32 is reduced.

FIG. 3- (a) shows a state in which all the concave portions 41 and all the convex portions 42 of the connecting groove 4 are cut using the large roughing cutter 1 in which the tip convex portion 31 and the concave portion 32 are formed as shown in FIG. Show. The workpiece 5 is cut in a state where the rotary shaft 10 of the rough roughing cutter 1 coincides with the central axis O of the connection groove 4 to form a part of the connection groove 4.

As shown in FIG. 3A, when the large roughing cutter 1 shown in FIG. 1 has finished cutting the workpiece 5, the finishing Christmas cutter cuts in the section of the convex portion 42 of the connection groove 4. The cutting material 7 is left, and the concave part 32, the intermediate transition part 35, and the original side transition part 36 cut the workpiece 5 for forming the convex part 42. The cutting allowance 7 cut by the finishing Christmas cutter in the section of the convex portion 42 is a solid line (outline of the large roughing cutter 1) in the radial direction of the connecting groove 4 with the central axis O as the center as shown in FIG. And the two-dot chain line (the outline of the Christmas cutter for finishing).

In the section of the recess 41 of the connection groove 4, the large roughing cutter 1 leaves a cutting allowance 8 cut by the roughing Christmas cutter 6 as shown in FIG. The part 33 and the original convex part 34 cut the work material 5 for forming the concave part 41. In FIG. 3- (b), the two-dot chain line indicates the outline of the cutter 1 for roughing, the solid line indicates the outline of the Christmas cutter 6 for roughing during or after cutting, and the broken line indicates the finish processing. The position of the surface of the recessed part 41 and the convex part 42 after a process is shown. The cutting allowance 8 cut by the roughing Christmas cutter 6 in the section of the recess 41 is the difference between the solid line and the broken line in the radial direction of the connection groove 4 in FIG.

The details of FIG. 3B are shown on the left side of FIG. 5, but the rough roughing cutter 1 cuts the sections indicated by the solid lines AB, CD, and EF at the position of the convex portion 42 of the connecting groove 4 to form the concave portion 41. In this section, the sections indicated by the solid lines of BC, DE, and FG are cut. In FIG. 5, the solid line indicates the outline of the large roughing cutter 1. An alternate long and two short dashes line indicates the positions of the surfaces of the concave portion 41 and the convex portion 42 after the finishing process, and indicates a range to be cut by the finishing Christmas cutter. The outline of the rough roughing cutter 1 in the section of the convex portion 42 indicates the outline of the intermediate transition portion 35 and the original transition portion 36.

As shown in FIG. 5, the outline of the rough roughing cutter 1 in the section of the convex portion 42 passes along the line leaving the cutting allowance 7 of the finishing Christmas cutter, and draws a curve along the surface of the convex portion 42. The outline of the large roughing cutter 1 in the recess 41 passes through a line that leaves the cutting allowance 8 cut by the roughing Christmas cutter 6 and draws a straight line parallel to the rotary shaft 10. In this example, the outline of the rough roughing cutter 1 in the section of the protrusion 42 is continuous with the outline of the recess 41, and the curvature of the curve continuously changes from the outline of the recess 41.

After cutting the workpiece 5 with the rough roughing cutter 1, as shown in FIG. 3- (b), the cutting allowance 7 cut by the finishing Christmas cutter is left in the section of the recess 41 of the connecting groove 4, as shown in FIG. Each of the convex portions (62, 64, 66) of the roughing Christmas cutter 6 shown in FIG. The cutting allowance 7 cut by the finishing Christmas cutter in the section of the recess 41 is the difference between the broken line and the two-dot chain line in the radial direction of the connecting groove 4.

The cutting edge 61 of the roughing Christmas cutter 6 is also shown by a solid line in FIG. 3B and in the axial direction as shown by a broken line in FIG. Correspondingly, a convex portion (62, 64, 66) in which the distance from the rotary shaft 60 in the axial direction to the farthest position in the direction perpendicular to the rotary shaft 60 gradually increases from the depth side to the surface side. ) And concave portions (63, 65, 67) are alternately formed.

The convex portion of the roughing Christmas cutter 6 corresponds to the convex portion 30 of the large roughing cutter 1 shown in FIG. 1, and extends from the tip end side in the axial direction to the shank portion 2 and is located in the section FG in FIG. Tip side convex portion 62 (corresponding to tip convex portion 31), intermediate portion convex portion 64 located in section DE (corresponding to intermediate convex portion 33), section BC (original side convex portion) 34) (corresponding to 34) is divided into a convex portion 66 on the shank portion side.

Similarly, the concave portion of the Christmas cutter 6 for roughing is located in the section EF (corresponding to the concave portion 32) in the section EF, and is located in the section CD (corresponding to the intermediate transition section 35). The concave portion 65 is divided into a shank portion-side concave portion 67 (corresponding to the original transition portion 36) located in the section AB.

The outline of the Christmas cutter 6 for roughing passes through the position indicated by the broken line in FIG. 5, and the sections AB, CD, and EF at the position of the convex portion 42 of the connection groove 4 (the shank portion side concave portion 67, the intermediate concave portion) 65, the concave portion 63 on the front end side is located closer to the rotation axis 60 (10) than the outline of the cutter 1 for roughing, so that the roughing Christmas cutter 6 is cut in the sections AB, CD, and EF. The material 5 is not cut.

On the other hand, in the BC, DE, and FG sections (the shank portion-side convex portion 66, the intermediate portion convex portion 64, and the tip-side convex portion 62) at the position of the concave portion 41 of the connection groove 4, the outline is for rough machining. Since it is located on the opposite side (working material 5 side) of the rotary shaft 60 (10) from the outline of the cutter 1, the roughing Christmas cutter 6 puts the work material 5 into the recess 41 in the sections BC, DE, and FG. Cut along the shape along with the cutting allowance 7 by the Christmas cutter for finishing.

In this relationship, the cutting edge for cutting the concave portion 41 (the work material 5 for formation) is formed on the surface of the convex portions 62, 64, 66 as described above. As described above, the cutting edge extends from the tip end in the axial direction of the blade portion 3 to the shank portion 2 and protrudes at the edge on the outer peripheral side in the radial direction of the rake face that forms a chip discharge groove formed continuously along the axial direction. It is formed as a ridge line or the like.

Many ranges in the direction of the central axis O of the convex portion 42 (work material 5 for forming) are the concave portion 32, the intermediate transition portion 35, and the original side transition portion 36 of the rough roughing cutter 1 due to the Christmas cutter for finishing. Since cutting is performed while leaving the cutting allowance 7, it is not necessary to form a cutting edge on the surface of the concave portions 63, 65, 67 of the Christmas cutter 6 for roughing.

As shown in FIG. 5, the distance from the rotating shaft 60 (in the direction perpendicular to the rotating shaft 60) to the surface of the concave portions 63, 65, 67 of the roughing Christmas cutter 6 is a connecting groove cut in a large roughing process. Since the distance to the surface of the fourth convex portion 42 is smaller than the distance from the rotation shaft 60, the cutting edges are not formed at all or only partially on the surfaces of the concave portions 63, 65, and 67.

“No cutting edge” means that no convex ridge line or the like is formed on the edge on the radially outer side of the rake face constituting the chip discharge groove, for example, a convex ridge line to be a cutting edge. Say that is chamfered.

After the workpiece 5 is cut by the roughing Christmas cutter 6, as shown in FIG. 3- (c), the finishing Christmas cutter having the outline shown by the broken lines in FIGS. The work material 5 is cut over the entire length in the direction of the central axis O. The finish processing Christmas cutter is a finish processing Christmas cutter indicated by a broken line in (a) and (b) in the above-described convex portion 42 and concave portion 41 after the large roughing cutter 1 and the roughing Christmas cutter 6 are cut. The cutting allowance 7 is cut to form the connection groove 4 after the finishing process shown in FIG.

FIGS. 6- (a) to (c) show examples of forming the blade portion 3 different from the large roughing cutter 1 shown in FIGS. 1 to 3 and FIG. (A) has a diameter more than the diameter of the intermediate | middle convex part 33 in the area from the part near the shank part 2 of the intermediate | middle convex part 33 in the example of FIG. The original convex portion 34 having a shape that gradually increases in diameter is formed, and the clear intermediate transition portion 35 in the example of FIG. 1 is not formed between the intermediate convex portion 33 and the original convex portion 34. An example of the case is shown. The contour line of the original convex portion 34 is inclined by about 10 ° with respect to the rotation axis 10.

FIG. 6- (b) shows that the section from the intermediate transition part 35 to the original side transition part 36 in the example of FIG. 1 remains in the state of the example of FIG. An example in which the section up to the transition part 35 is formed in a shape in which the diameter gradually increases toward the shank part 2 side is shown. (C) The diameter gradually increases from the axially distal end portion of the intermediate convex portion 33 in (b) to the axially intermediate portion of the original convex portion 34 continuously toward the shank portion 2 side. An example in the case of forming in a shape to be shown. Also in the examples of (b) and (c), the outline of the original convex portion 34 is inclined by about 10 ° with respect to the rotating shaft 10. The example shown in (c) corresponds to a shape in which the intermediate transition part 35 in the example shown in FIG.

　 Here, the blade when the same work material is cut under the same cutting conditions using the large roughing Christmas cutter of Patent Document 2 and the large roughing cutter 1 of the present invention as the conventional large roughing Christmas cutter. The degree of resistance (cutting resistance) that the part receives from the work material is compared. The cutting conditions are as shown in Table 1 below. Conventional rough roughing is the Christmas cutter for rough roughing of Patent Document 2, and new rough roughing 1 and 2 are the rough roughing cutter 1 of the present invention. Here, the two rough cutting cutters 1 and the large roughing Christmas cutter 2 are used, but the number of blades is arbitrary. As the work material 5, SNCM439 (nickel chromium molybdenum steel) was used.

　
　
　 As can be seen from the comparison between Fig. 4- (a) and Fig. 3- (a), the conventional large rough and the new large rough 1, 2 have different maximum lines due to the difference in outline (form) even if the minimum diameter is the same. Therefore, strictly speaking, it is difficult to compare under exactly the same conditions. However, by comparing the resistance values when the rotation speed n and table feed (speed) of the new rough rough 1 and 2 are more severe than the conventional rough rough, the low resistance (burden) of the new rough rough 1 and 2 is highlighted. It is considered to be. The cutting speed V (mm / min) in Table 1 is obtained as n · D · π / 1000 from the outer diameter D (mm) and the rotation speed n (/ min). Table 2 shows the magnitude of the resistance that the blade receives from the work material.

In Table 2, “maximum” and “minimum” are the maximum and minimum resistance values in the X direction, Y direction, and Z direction (rotational axis direction), and the unit is N (Newton). “Amplitude” indicates the sum of absolute values of “maximum” and “minimum”. The larger this value, the higher the possibility that chatter vibration will occur in the blade portion 3. “Maximum” and “minimum” of the “combined force” indicate values at a position where the total value (X + Y + Z) in the X direction, the Y direction, and the Z direction is maximum and minimum.

Compared with the conventional large rough 1 and the new large rough 1, the new large rough 1 as shown in Table 1, while the rotational speed n and the table feed (speed) are increased from 210 to 300 and 12 to 15, respectively, compared to the conventional large rough as shown in Table 1. In addition, the resistance value in the X direction decreases with 8229 → 6993 (85%), and the resistance value in the Y direction decreases with 9157 → 7197 (78.6%). The resultant force also decreases from 7335 to 6395 (87.2%). Although the resistance value in the Z direction increases from 832 to 1059 (127.3%), it can be said that the influence on chatter vibration is small because it is in the rotation axis direction (material axis direction).

Similarly, when comparing the conventional large rough and the new large rough 2, the new large rough 2 as shown in Table 1, while the rotational speed n and the table feed (speed) are increased from 210 to 300 and 12 to 17, respectively, compared to the conventional large rough, Table 2 Thus, the resistance value in the X direction decreases with 8229 → 7625 (92.7%), and the resistance value in the Y direction decreases with 9157 → 8039 (87.8%). The resultant force also decreases from 7335 to 6880 (93.8%). Although the resistance value in the Z direction increases from 832 to 1205 (144.8%), since it is in the rotation axis direction (material axis direction), the influence on chatter vibration is small.

From the results of Tables 1 and 2, when the same roughing material as the rough cutting Christmas cutter of Patent Document 2 was cut using the large roughing cutter 1 of the present invention under the same cutting conditions, the rotation speed n Even if the table feed is increased, the resistance value during cutting in the X direction and the Y direction, which has an effect on chatter vibration, may decrease, and chatter vibration may occur. Patent Document 2 shown in FIG. It can be seen that this is lower than the large roughing Christmas cutter.

This advantage is that the blade portion 3 has an intermediate convex portion 33 and an original convex portion 34 that are parallel to the rotary shaft 10, and has an irregular shape like the conventional large roughing Christmas cutter shown in FIG. It can be said that it is obtained as a result of suppressing the maximum diameter by not having a certain elevational shape. Moreover, it can be said that the cutting efficiency (efficiency) of the large roughing cutter 1 of the present invention for the work material is higher than the cutting efficiency of the conventional large roughing Christmas cutter due to the effect of reducing chatter vibration.

1 ... Cutter for rough machining, 10 ... Rotating shaft,
2 ... Shank, 3 ... Blade, 3a ... Cutting blade, 3b ... Chip discharge groove,
30... Convex part, 31... Convex part at the tip, 32 ... Concave part, 33 ... Intermediate convex part, 34 ... Original convex part, 35 ... Intermediate transition part, 36 ... Original side Transition department,
4 ... Connection groove, 41 ... Concave, 410 ... Deepest concave, 42 ... Convex, 420 ... Deepest convex, O ... Central axis,
5. Work material,
6 ... Christmas cutter for roughing, 60 ... Rotating shaft, 61 ... Blade,
62... Convex portion on the tip side, 63... Concave portion on the tip side, 64... Convex portion on the intermediate portion, 65... Concave portion on the intermediate portion, 66. Concave part,
7 …… Cutting allowance for Christmas cutter for finishing,
8: Cutting cost for roughing Christmas cutters.

Claims (9)

A plurality of concave portions and a plurality of convex portions are alternately and repeatedly formed in the depth direction of the work material, and the respective concave portions and the respective convex portions are perpendicular to the central axis from the central axis facing the depth direction. A rough roughing process for roughing a connection groove for connecting a turbine blade having a Christmas tree-like cross-sectional shape in which the distance to the farthest position in the direction gradually increases from the depth side to the surface side in the depth direction. And then used in the rough roughing step of the method of cutting through the roughing step for subsequent roughing and the finishing step for subsequent finishing.
A cutter for large roughing that cuts the plurality of concave portions and the plurality of convex portions of the connection groove and has a blade portion having a cutting edge in the entire axial length on the tip end side in the axial direction of the shank portion,
In the section on the shank part side excluding the tip part in the axial direction of the blade part, the concave part other than the concave part on the innermost side in the depth direction and the convex part other than the convex part on the innermost side are cut. A convex part is formed,
This convex part is divided into an intermediate convex part near the tip in the axial direction and an original convex part having a diameter larger than the diameter of the intermediate convex part near the shank part,
The outline of at least a section corresponding to the concave portion of at least one of the intermediate convex portion and the original convex portion is parallel to the axial rotation axis,
At least one section between the intermediate convex section and the original convex section and between the original convex section and the shank section, the axis of the convex section from the one section A cutter for cutting a turbine blade connection groove, wherein a transition portion having a diameter equal to or larger than a diameter of a portion located on the front end side in the direction is formed. An intermediate transition portion having a diameter equal to or larger than the diameter of the intermediate convex portion is formed between the intermediate convex portion and the original convex portion, and the intermediate convex portion is interposed between the original convex portion and the shank portion. The cutter for turbine blade connection groove cutting according to claim 1, wherein a former side transition portion having a diameter equal to or larger than a diameter of the former convex portion is formed. The outline of one of the intermediate convex part and the original convex part is drawn from the axial front end side to the shank part side to draw a straight line or a curve in which the diameter of the convex part increases. The cutter for cutting a turbine blade connection groove according to claim 1 or 2, characterized by the above-mentioned. At least one of the transition portions of at least one of the transition portions corresponding to the convex portion has a contour line extending from the axial front end side to the shank portion side, and draws a curve in which the diameter of the convex portion gradually increases. The turbine blade connecting groove cutting cutter according to any one of claims 1 to 3, wherein the cutter is provided. A concave portion is formed which is continuous to the tip end side in the axial direction of the convex portion and cuts the convex portion on the innermost side, and is continuous to the tip end side in the axial direction of the concave portion and cuts the concave portion on the innermost side. The cutter for cutting a turbine blade connection groove according to any one of claims 1 to 4, wherein a tip convex portion is formed. The turbine blade connecting groove cutting cutter according to claim 5, wherein the tip convex portion is formed in a shape having a diameter that decreases from the shank portion side to the tip end side in the axial direction. A plurality of concave portions and a plurality of convex portions are alternately and repeatedly formed in the depth direction of the work material, and the respective concave portions and the respective convex portions are perpendicular to the central axis from the central axis facing the depth direction. This is a method of cutting a connection groove for connecting a turbine blade having a Christmas tree-like cross-sectional shape in which the distance to the farthest position in the direction gradually increases from the depth side to the surface side in the depth direction. Cutting the connecting groove through a large roughing process for processing, a roughing process for subsequent roughing, and a finishing process for subsequent finishing,
The cutting of the turbine blade connection groove characterized in that, in the large roughing step, the concave portion and the convex portion of the connection groove are cut using the large roughing cutter according to any one of claims 1 to 6. Processing method. In the roughing step, convex portions and concave portions corresponding to the plurality of concave portions and the plurality of convex portions of the connection groove are alternately formed in the axial direction of the blade portion, and the surface of the convex portion is A cutting edge for cutting the concave portion of the connecting groove is formed, and the concave portion of the connecting groove is used with a roughing Christmas cutter in which a cutting edge is not formed on at least a part of the surface of at least a part of the concave portion. The method for cutting a turbine blade connection groove according to claim 7, wherein the convex portion is cut. A plurality of concave portions and a plurality of convex portions are alternately and repeatedly formed in the depth direction of the work material, and the respective concave portions and the respective convex portions are perpendicular to the central axis from the central axis facing the depth direction. This is a method of manufacturing a connection groove for connecting a turbine blade having a Christmas tree-shaped cross-sectional shape in which the distance to the farthest position in the direction gradually increases from the depth side to the surface side in the depth direction. The connecting groove is manufactured through a large roughing process, a roughing process that performs roughing, and a finishing process that performs finishing.
In the said rough roughing process, the said recessed part and the said convex part of the said connection groove are cut using the cutter for rough roughing in any one of Claim 1 thru | or 6, The manufacture of the turbine blade connection groove characterized by the above-mentioned. Method.

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