Rotary blade tool, cutting machine

Abstract

To provide a rotary blade tool which can cut an object into a circular shape with good accuracy, and can change a cutting radius without changing a fulcrum position.SOLUTION: A rotary blade tool 30 comprises a disk part 31, a cutting part 32, and a recess 33. The disk part 31 is so formed as to be curved into a curve surface shape so that a central part thereof projects in X1 direction. The cutting part 32 is formed on an outer periphery of the disk part 31. The recess 33 is provided on the central part of the disk part 31, and is so formed as to be concaved in X2 direction from the disk part 31. A motor rotary shaft 41 is assembled to a bottom 330 of the recess 33.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a rotary blade and a cutting machine. [Background technology]

[0002] Conventionally, there is a cutting machine described in the following Patent Document 1. This cutting machine is equipped with a disk-shaped rotary blade and a motor that rotates the rotary blade. This cutting machine is capable of cutting an object by bringing the rotating rotary blade into contact with the object. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-226071 A Summary of the Invention [Problem to be solved by the invention]

[0004] The rotary blade described in Patent Document 1 is formed in a disk shape, and therefore although it is effective for cutting an object in a linear manner, it is difficult to cut an object in a circular shape with high precision. The present invention has been made in consideration of the above-mentioned situation, and its object is to provide a rotary blade and a cutting machine that are capable of cutting an object into a circular shape with high precision and that enable the cutting radius to be changed without changing the fulcrum position. [Means for solving the problem]

[0005] A rotary blade that solves the above problem includes a disk portion, a blade portion, and a recess. The disk portion is formed by bending into a curved shape so that a central portion protrudes in a first direction. The blade portion is formed on the outer periphery of the disk portion. The recess is provided in the central portion of the disk portion and is formed to be recessed from the disk portion in a second direction opposite to the first direction. A rotating shaft of a motor is attached to the bottom of the recess.

[0006] A cutting machine that solves the above problem includes the rotary blade and a motor. The motor has a rotation shaft that is attached to the rotary blade and rotates the rotary blade via the rotation shaft. According to this configuration, the rotation of the curved disk portion causes the rotary blade to move in a circular motion, so that the cutting object can be cut into a circular shape with high precision. Also, by attaching the motor shaft to the bottom of the motor, the position of the disk portion can be offset from the fulcrum position, which is the position where the motor bottom and the motor shaft are attached, so that the cutting radius can be changed without changing the fulcrum position. Effect of the Invention

[0007] According to the rotary blade and cutter of the present invention, it is possible to cut an object into a circular shape with high accuracy, and it is also possible to change the cutting radius without changing the fulcrum position. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing a perspective structure of a cutting machine according to a first embodiment. [Diagram 2] FIG. 2 is an exploded perspective view showing a cutting machine according to the first embodiment; [Diagram 3] FIG. 2 is a front view showing the front structure of the rotary blade according to the first embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing a partial cross-sectional structure taken along line IV-IV in FIG. [Diagram 5] 4 is a cross-sectional view showing a partial cross-sectional structure taken along line VV in FIG. 3. [Figure 6] 3A to 3C are diagrams illustrating an example of the operation of the cutting machine according to the first embodiment. [Figure 7] FIG. 11 is a diagram illustrating an example of the operation of a cutting machine of a comparative example. [Figure 8] FIG. 4 is a cross-sectional view showing a cross-sectional structure of a rotary blade according to a first modified example of the first embodiment. [Figure 9] FIG. 11 is a cross-sectional view showing a cross-sectional structure of a rotary blade according to a second modified example of the first embodiment. [Figure 10]FIG. 13 is a cross-sectional view showing a cross-sectional structure of a rotary blade according to a third modified example of the first embodiment. [Figure 11] FIG. 11 is a cross-sectional view showing a cross-sectional structure of a rotary blade according to a second embodiment. [Figure 12] FIG. 11 is a cross-sectional view showing a cross-sectional structure of a rotary blade according to a modified example of the second embodiment. [Figure 13] FIG. 11 is a cross-sectional view showing a cross-sectional structure of a rotary blade according to a third embodiment. [Figure 14] FIG. 13 is a cross-sectional view showing a cross-sectional structure of a rotary blade according to a modified example of the third embodiment. [Figure 15] FIG. 13 is a cross-sectional view showing a cross-sectional structure of a rotary blade according to a modified example of the third embodiment. [Figure 16] FIG. 11 is a cross-sectional view showing a cross-sectional structure of a rotary blade according to another embodiment. [Figure 17] FIG. 11 is a cross-sectional view showing a cross-sectional structure of a rotary blade according to another embodiment. [Figure 18] FIG. 13 is a perspective view showing a perspective structure of a cutting machine according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of a rotary blade and a cutting machine will be described with reference to the drawings. In order to facilitate understanding of the description, the same components in each drawing are denoted by the same reference numerals as much as possible, and duplicated description will be omitted. First Embodiment (Cutting machine configuration) First, a schematic configuration of the cutting machine 10 of this embodiment will be described. The cutting machine 10 shown in FIG. 1 is used by an operator to cut asphalt for paving a road surface, for example. More specifically, when installing a utility pole on a road surface, an operator sequentially performs a process of cutting the asphalt forming the road surface to expose the ground, a process of embedding the base end of the utility pole into the ground, and a process of repaving the cut part of the road surface with asphalt. The cutting machine 10 of this embodiment is used to cut the asphalt into a circular shape in the process of cutting the asphalt to expose the ground. The cutting radius of the asphalt is, for example, around 80 cm. In the following, a material to be cut by the cutting machine 10, such as asphalt, is referred to as a "cutting object". In addition, an operator who cuts a desired cutting object using the cutting machine 10 is referred to as a "user".

[0010] As shown in FIG. 1, the cutting machine 10 includes a main body 20, a rotary blade 30, and a motor 40. The main body 20 is formed in a semi-cylindrical shape centered on an axis m10 shown in the figure. Hereinafter, one direction along the axis m10 is referred to as the "X1 direction", and the other direction along the axis m10 is referred to as the "X2 direction". In this embodiment, the X1 direction corresponds to the first direction, and the X2 direction corresponds to the second direction opposite to the first direction. A flat abutting portion 21 is provided at the bottom of the main body 20. The bottom surface of the abutting portion 21 is a portion that abuts against the object to be cut when the object is cut. A concave gripping portion 22 is provided at the top of the main body 20. The gripping portion 22 is a portion that is gripped by the user's hand. By gripping the gripping portion 22, the user can carry the cutting machine 10 and displace the cutting machine 10 relative to the object to be cut. In this way, the cutting machine 10 of this embodiment is a portable cutting machine that can be carried around.

[0011] A cover 23 is provided on the side surface of the main body 20 in the X1 direction. The cover 23 is formed in a hollow semidisk shape centered on the axis m10. The cover 23 is provided so as to cover approximately the upper half of the rotary blade 30. The cover 23 prevents fragments of the object to be cut by the rotary blade 30 from scattering around. A semicircular cutout portion 230 is formed in the center of the cover 23. The center portion of the rotary blade 30 is exposed to the outside from the cover 23 through the cutout portion 230.

[0012] The motor 40 is integrally assembled to the side surface of the main body 20 in the X2 direction. The rotating shaft of the motor 40 is disposed so as to extend from the side surface of the main body 20 in the X2 direction along the axis m10, penetrating the main body 20 in the X1 direction. As shown in Fig. 2, the tip of the rotating shaft 41 of the motor 40 is exposed to the inside of the cover 23 from the side surface of the main body 20 in the X1 direction. The rotary blade 30 is integrally assembled to the tip of the motor rotating shaft 41 by an assembly member 50.

[0013] The assembly member 50 includes a first circular member 51 , a second circular member 52 , and a bolt 53 . The first circular member 51 and the second circular member 52 are formed in an annular shape centered on the axis m10. A bolt 53 is inserted into insertion holes 510, 520 that pass through the central portions of the first circular member 51 and the second circular member 52 along the axis m10.

[0014] The rotary blade 30 is formed in a disk shape centered on the axis m10. An insertion hole 331 is formed in the center of the rotary blade 30 so as to penetrate along the axis m10. A bolt 53 is inserted into the insertion hole 331. An internally threaded hole 410 is formed in the motor rotating shaft 41 so as to extend inward along the axis m10 from the tip surface of the motor rotating shaft 41. A bolt 53 is screwed into the internally threaded hole 410.

[0015] When the rotary blade 30 is assembled to the motor shaft 41, the first circular ring member 51, the rotary blade 30, and the second circular ring member 52 are arranged so as to be stacked in order on the motor shaft 41. Next, the bolt 53 is inserted from the second circular ring member 52 side into the insertion hole 520 of the second circular ring member 52, the insertion hole 331 of the rotary blade 30, and the insertion hole 510 of the first circular ring member 51, and the bolt 53 is screwed into the female thread hole 410 of the motor shaft 41. As a result, the first circular ring member 51 and the second circular ring member 52 are fastened and fixed to the motor shaft 41. In addition, the rotary blade 30 is sandwiched between the first circular ring member 51 and the second circular ring member 52, so that the rotary blade 30, the first circular ring member 51, and the second circular ring member 52 are assembled together. With this structure, the rotary blade 30 is fixed together with the motor shaft 41 via the assembly member 50. 1, when the rotary blade 30 is attached to the motor shaft 41, the lower part of the rotary blade 30 protrudes downward from the contact part 21. This lower part of the rotary blade 30 comes into contact with the object to be cut and becomes the part that cuts the object.

[0016] (Structure of Rotary Blade) Next, the structure of the rotary blade 30 will be described in detail. Fig. 3 shows the front structure of the rotary blade 30. Fig. 4 shows the cross-sectional structure along line IV-IV in Fig. 3. Fig. 5 shows the cross-sectional structure along line VV in Fig. 3.

[0017] 3 to 5, the rotary blade 30 includes a disk portion 31, a blade portion 32, and a recessed portion 33. The rotary blade 30 is made of a material containing a copper as a main component and having diamond chips embedded therein. The disk portion 31 is a portion provided in the center of the rotary blade 30. As shown in Fig. 3, the disk portion 31 is formed in a circular shape centered on the axis m10 when viewed from the X1 direction side. As shown in Fig. 4, the disk portion 31 has a shape obtained by bending a disk into a curved shape with a curvature radius ra, and is formed in a spherical crown shape obtained by cutting out a part of a sphere.

[0018] 3, a plurality of blade portions 32 are formed on the outer circumferential portion of the disk portion 31. The plurality of blade portions 32 are formed at predetermined angular intervals in the circumferential direction centered on the axis m10. As shown in FIG. 4, the recess 33 is formed in the center of the disk portion 31. The recess 33 is formed by recessing the center of the disk portion 31 in the X2 direction. An insertion hole 331 is formed in a bottom portion 330 of the recess 33 so as to penetrate the bottom portion 330 in the X1 direction. An intermediate portion of the bolt 53 is inserted into the insertion hole 331. The bottom portion 330 is disposed offset in the second direction from the entire disk portion 31. A side wall portion 332 provided between the bottom portion 330 and the disk portion 31 in the recess 33 is formed in a tapered shape so as to become wider from the bottom portion 330 toward the disk portion 31.

[0019] In the rotary blade 30 of this embodiment, the disk portion 31 and the recess 33 are integrally formed. Such disk portion 31 and recess 33 are manufactured, for example, by forming a primary molded product by bending a disk-shaped material into a curved shape in the X1 direction by press working, and then deforming a central part of the primary molded product into a concave shape in the X2 direction by spinning.

[0020] As shown in Fig. 4, the rotary blade 30, together with a first circular member 51 and a second circular member 52, is fastened and fixed to the motor shaft 41 by a bolt 53. This allows the rotary blade 30 to rotate integrally with the motor shaft 41. In Fig. 4, the position on the axis m10 where the disk part 31 and the motor shaft 41 are connected is indicated by the symbol P10. Hereinafter, this position P10 will be referred to as the "fulcrum position P10."

[0021] (Example of cutting machine operation) Next, an example of the operation of the cutting machine 10 of this embodiment will be described. Note that, in the following, an example will be described in which the object to be cut is asphalt that forms the surface of a road or the like.

[0022] When cutting asphalt with the cutting machine 10, first, a cut is made in the asphalt, and then the rotary blade 30 is inserted into the cut, so that the lower part of the rotary blade 30 is placed in the asphalt road surface G, as shown in FIG. 5, for example. When the motor 40 is driven in this state, the motor shaft 41 rotates around the axis m10. The rotary blade 30 rotates around the axis m10 with the rotation of the motor shaft 41, and cutting of the asphalt is started. At this time, as shown in FIG. 6, when a user positioned at point U10 displaces the cutting machine 10 while holding the cutting machine 10 so as to draw a circle around point U10, the rotary blade 30 displaces along the dashed line L10, which is a circular orbit of radius r10 centered on point U10. Therefore, since the part of the dashed line L10 is cut, it is possible to cut the asphalt in a circular shape of radius r10. In the following, this radius r10 is also referred to as the "cutting radius r10".

[0023] (Actions and Effects of the Cutting Machine of the Present Embodiment) As described above, the rotary blade 30 of this embodiment includes the disk portion 31, the blade portion 32, and the recessed portion 33. The disk portion 31 is formed by being bent into a curved shape so that the central portion protrudes in the X1 direction. The blade portion 32 is formed on the outer periphery of the disk portion 31. The recessed portion 33 is provided in the central portion of the disk portion 31 and is formed to be recessed from the disk portion 31 in the X2 direction. The rotating shaft 41 of the motor 40 is attached to the bottom portion 330 of the recessed portion 33.

[0024] According to this configuration, the curved disk portion 31 rotates around the rotation shaft 41 of the motor 40, and the rotary blade 30 is displaced so as to draw a circle along the dashed line L10 shown in Fig. 6. Therefore, it is possible to cut the object to be cut, such as asphalt, into a circular shape with high accuracy.

[0025] Incidentally, when cutting an object such as asphalt using the cutting machine 10 of this embodiment, for example, as shown in FIG. 6, a structure 60 such as a retaining wall may exist around the cutting location. In this case, the cutting machine 10 must be used so that the cover 23 does not come into contact with the structure 60. Specifically, if the outermost part of the cover 23 draws a circular orbit of radius r20 as shown by the two-dot chain line L20 when the cutting machine 10 is rotated around the point U10, the cutting machine 10 must be used so that the two-dot chain line L20 does not come into contact with the structure 60. Hereinafter, this radius r20 is also referred to as the "working radius r20".

[0026] On the other hand, when the rotary blade 300 of the comparative example shown in FIG. 7 is used, the cutting radius is "r11". The rotary blade 300 of the comparative example has the same structure as the rotary blade 30 of the present embodiment, except that the recess 33 is not formed in the disk part 31. In the rotary blade 300 of the comparative example, the recess 33 is not formed in the disk part 310, so that the bolt 53 is arranged to protrude from the disk part 310 as shown in FIG. 7. Due to such a structure, the rotary blade 300 of the comparative example is located closer to the center point U10 than the rotary blade 30 of the present embodiment shown in FIG. 6. Therefore, the cutting radius r11 of the rotary blade 300 of the comparative example is smaller than the cutting radius r10 of the rotary blade 300 of the present embodiment. In other words, when the rotary blade 30 of the present embodiment is used, it is possible to make the cutting radius larger than when the rotary blade 300 of the comparative example is used. As a result, the rotary blade 300 of this embodiment can cut a portion closer to the structure 60, thereby improving workability.

[0027] Furthermore, if the rotary blade 30 of this embodiment is used instead of the rotary blade 300 of the comparative example as shown in FIG. 7, it is possible to change the cutting radius from "r11" to "r10" without changing the fulcrum position P10. In the rotary blade 30 of this embodiment, as shown in FIG. 4, the bottom portion 330 is positioned offset from the entire disk portion 31 in the second direction.

[0028] According to this configuration, the disk portion 31 can be offset more significantly in the X1 direction with respect to the fulcrum position P10, so that the cutting radius can be changed more significantly. (First Modification) Next, a first modified example of the cutting machine 10 of the first embodiment will be described.

[0029] As shown in FIG. 8, in the rotary blade 30 of this modified example, the disk portion 31 and the recess 33 are formed of different members, and the recess 33 is joined to the disk portion 31. Specifically, the bottom 330 and the side wall 332 of the recess 33 are formed of different members by machining or the like. The recess 33 is formed by joining the outer periphery of the bottom 330 and the end of the side wall 332 in the X2 direction by welding or the like. Meanwhile, an opening 311 is formed in the center of the disk portion 31 so as to penetrate the disk portion 31 in the X1 direction along the axis m10. The disk portion 31 and the recess 33 are joined to each other by joining the inner periphery of the opening 311 of the disk portion 31 and the end of the side wall 332 in the X1 direction of the recess 33 by welding or the like.

[0030] In the rotary blade 30 of this modification, the side wall 332 of the recess 33 is parallel to the X1 and X2 directions. Even with this configuration, it is possible to obtain the same or similar actions and effects as those of the cutting machine 10 of the first embodiment described above. (Second Modification) Next, a second modified example of the cutting machine 10 of the first embodiment will be described.

[0031] As shown in Fig. 9, the recess 33 of the disk portion 31 of this modified example is formed to have a shallower groove depth than the recess 33 of the disk portion 31 shown in Fig. 4. As a result, the bottom 330 of the recess 33 is provided at a position facing the disk portion 31 in a direction perpendicular to the X2 direction.

[0032] According to this configuration, it is possible to further reduce the offset amount of the disk portion 31 in the X2 direction from the fulcrum position P10. As a result, it is possible to further reduce the change in the cutting radius. (Third Modification) Next, a third modified example of the cutting machine 10 of the first embodiment will be described.

[0033] As shown in Fig. 10, the recess 33 of the disk portion 31 of this modified example is formed with a deeper groove compared to the recess 33 of the disk portion 31 shown in Fig. 4. As a result, the bolt 53 is positioned offset in the second direction from the entire disk portion 31. According to this configuration, it is possible to increase the offset amount of the disk portion 31 in the X2 direction from the fulcrum position P10. As a result, it is possible to change the cutting radius more greatly.

[0034] <Second embodiment> Next, a cutting machine 10 according to a second embodiment will be described. The following description will focus on the differences from the cutting machine 10 according to the first embodiment. (Structure of Rotary Blade) In the rotary blade 30 of this embodiment, a recess 34 as shown in FIG. 11 is provided instead of the recess 33 as shown in FIG. 4. The recess 34 is formed so as to protrude in a concave shape in the X1 direction. The disk portion 31 and the recess 34 of this embodiment are manufactured, for example, by forming a primary molded product by bending a disk-shaped material into a curved shape in the X1 direction by press working, and then deforming a central part of the primary molded product into a concave shape in the X1 direction by spinning. In the rotary blade 30 of this embodiment, the side wall portion 342 of the recess 34 is also formed in a tapered shape so that the width becomes wider from the bottom portion 340 toward the disk portion 31. The bottom portion 340 is formed with an insertion hole 341 into which the middle portion of the bolt 53 is inserted.

[0035] (Actions and Effects of the Cutting Machine of the Present Embodiment) In the cutting machine 10 of this embodiment, similarly to the cutting machine 10 of the first embodiment, the curved disk portion 31 rotates around the rotation shaft 41 of the motor 40, so that the cutting object such as asphalt can be cut into a circular shape with high precision. In this case, the cutting radius of the rotary blade 30 of this embodiment can be made smaller than that of the rotary blade 300 of the comparative example shown in Fig. 7.

[0036] (Modification) Next, a modified example of the cutting machine 10 of the second embodiment will be described. As shown in FIG. 12, in the rotary blade 30 of this modification, similarly to the rotary blade 30 of the first modification of the first embodiment, the disk portion 31 and the recess 34 are formed of different members, and the recess 34 is joined to the disk portion 31. Specifically, the bottom 340 and the side wall 342 of the recess 34 are formed of different members by machining or the like. The recess 34 is formed by joining the outer periphery of the bottom 340 and the end of the side wall 342 in the X1 direction by welding or the like. Meanwhile, an opening 311 is formed in the center of the disk portion 31 so as to penetrate the disk portion 31 in the X1 direction along the axis m10. The disk portion 31 and the recess 34 are joined to each other by joining the inner periphery of the opening 311 of the disk portion 31 and the end of the side wall 342 in the X2 direction of the recess 34 by welding or the like.

[0037] In the rotary blade 30 of this modified example, the side wall portion 342 of the recess 34 is parallel to the X1 direction and the X2 direction. Even with this configuration, it is possible to obtain the same or similar actions and effects as those of the cutting machine 10 of the first embodiment described above. <Third embodiment> Next, a cutting machine 10 according to a third embodiment will be described. The following description will focus on the differences from the cutting machines 10 according to the first and second embodiments.

[0038] (Cutting machine configuration) As shown in FIG. 13, in the cutting machine 10 of this embodiment, two rotary blades 30a, 30b are attached to the motor shaft 41. One rotary blade 30a has a shape similar to that of the rotary blade 30 of the first embodiment shown in FIG. 4, and has a recess 33 formed so as to recess from the disk part 31 in the X2 direction. The other rotary blade 30b has a shape similar to that of the rotary blade 30 of the second embodiment shown in FIG. 11, and has a recess 34 formed so as to protrude from the disk part 31 in the X1 direction. The radius of the disk part 31 of one rotary blade 30a is larger than the radius of the disk part 31 of the other rotary blade 30b. In this embodiment, the rotary blade 30a corresponds to the first rotary blade, and the rotary blade 30b corresponds to the second rotary blade.

[0039] (Actions and Effects of the Cutting Machine of the Present Embodiment) Each of the rotary blades 30a, 30b can cut an object such as asphalt with a cutting radius corresponding to the rotary blade 30a, and can also cut with a cutting radius corresponding to the rotary blade 30b.

[0040] (Modification) Next, a modification of the cutting machine 10 of the third embodiment will be described. The types of the two rotary blades attached to the motor shaft 41 can be changed as appropriate.

[0041] For example, rotary blades 30c and 30d as shown in Fig. 14 may be attached to the motor shaft 41. One of the rotary blades, 30c, has a shape similar to the rotary blade 300 of the comparative example shown in Fig. 7. The other rotary blade 30d has a shape similar to the rotary blade 30 of the second embodiment shown in Fig. 11.

[0042] Rotary blades 30e, 30f as shown in Fig. 15 may be attached to the motor shaft 41. One of the rotary blades, 30e, has a shape similar to the rotary blade 30 of the first embodiment shown in Fig. 4. The other rotary blade 30f has a shape similar to the rotary blade 300 of the comparative example shown in Fig. 7.

[0043] Even with such a structure, it is possible to obtain the same or similar actions and effects as the cutting machine 10 of the third embodiment. <Other embodiments> The present disclosure is not limited to the above specific examples.

[0044] For example, as shown in Fig. 16, in the cutting machine 10 of the first embodiment, the rotary blade 30 may be attached in an inverted manner relative to the motor shaft 41. The same applies to the other embodiments and modified examples. 17, the cover 23 may be formed so as to be curved along the outer surface of the rotary blade 30. According to this configuration, the working radius can be made smaller, and therefore the workability can be further improved.

[0045] The rotary blade 30 of each embodiment and modification can be mounted on a cutting machine 100 as shown in FIG. 18. The cutting machine 100 includes a motor that transmits a rotational force to the rotary blade 30, and a tilting means that can tilt the rotary blade 30 up and down with respect to the road surface based on the operation of a lever. With this configuration, the cutting machine 100 can make the rotary blade 30 rotated by the motor cut into the road surface (direction A in the figure). The bottom of the cutting machine 100 is provided with an engagement member (not shown) that can be engaged with a support shaft and wheels, and can rotate around the support shaft. As a result, the rotary blade 30 that has been cut into the road surface can be turned around the support shaft in a range of 360° to draw an arc (direction B in the figure) to cut the road surface. The cutting machine 100 can also use the rotary blades 30a to 30f of the third embodiment.

[0046] The above specific examples, to which a person skilled in the art may make appropriate design modifications, are also included within the scope of the present disclosure as long as they have the features of the present disclosure. The elements of each of the above specific examples, as well as their arrangements, conditions, shapes, etc., are not limited to those exemplified and can be modified as appropriate. The elements of each of the above specific examples can be combined as appropriate as long as no technical contradictions arise. [Explanation of symbols]

[0047] 10: cutting machine, 30: rotary blade, 30a: rotary blade (first rotary blade), 30b: rotary blade (second rotary blade), 30c to 30f: rotary blade, 31: disk portion, 32: blade portion, 33, 34: recess, 40: motor, 41: rotating shaft, 330, 340: bottom portion, 332, 332: side wall portion.

Claims

1. a disk portion formed by bending a central portion into a curved shape so as to protrude in a first direction; A blade portion formed on the outer periphery of the disk portion; a recess provided in a central portion of the disk portion and recessed from the disk portion in a second direction opposite to the first direction, The rotating shaft of the motor is attached to the bottom of the recess. Rotary cutting tool.

2. The bottom of the recess is offset in the second direction from the entire disk portion. The rotary blade according to claim 1.

3. The bottom of the recess is provided at a position facing the disk portion in a direction perpendicular to the second direction. The rotary blade according to claim 1.

4. The sidewall of the recess is tapered so that its width increases from the bottom toward the disk portion. The rotary blade according to claim 1.

5. The side wall of the recess is formed parallel to the first direction. The rotary blade according to claim 1.

6. The disk portion and the recessed portion are integrally formed. The rotary blade according to claim 1.

7. The disk portion and the recessed portion are formed of separate members and joined together. The rotary blade according to claim 1.

8. A disk portion formed by bending a central portion into a curved shape so as to protrude in a first direction; A blade portion formed on the outer periphery of the disk portion; a recess provided in a central portion of the disk portion and formed to protrude from the disk portion in the first direction, The rotating shaft of the motor is attached to the bottom of the recess. Rotary cutting tool.

9. The sidewall of the recess is tapered so that its width increases from the bottom toward the disk portion. The rotary blade according to claim 8.

10. The side wall of the recess is formed parallel to the first direction. The rotary blade according to claim 8.

11. The disk portion and the recessed portion are integrally formed. The rotary blade according to claim 8.

12. The disk portion and the recessed portion are formed of separate members and joined together. The rotary blade according to claim 8.

13. A rotary blade according to any one of claims 1 to 12, a motor having a rotation shaft attached to the rotary blade and rotating the rotary blade via the rotation shaft; cutting machine.

14. When the rotary blade is a first rotary blade, The blade further includes a second rotary blade different from the first rotary blade.

14. The cutting machine according to claim 13.

15. The radius of the disk portion of the first rotary blade is different from the radius of the disk portion of the second rotary blade.

15. The cutting machine according to claim 14.

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