JP3844288B2 - Grinding blade, grinding apparatus and grinding method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a blade for a grinding apparatus, a grinding apparatus using the blade, and a grinding method using the grinding apparatus.
[0002]
[Prior art]
As a wound electronic component, a wound inductor having a drum core wound is best known. In order to obtain this type of wound inductor, conventionally, a round rod-shaped ferrite core is processed to produce a drum core having circular collar portions at both ends in the axial direction. It is common to wind a wire having a necessary number of turns and a wire diameter. Such a wire-wound inductor is found in many known documents such as Japanese Utility Model Laid-Open No. 51-115547 and Japanese Patent Laid-Open No. 57-73916.
[0003]
In the case of a wire-wound inductor having circular collar portions at both ends in the axial direction, it is necessary to take measures for eliminating the rolling property of the circular collar portions when surface-mounted on a circuit board. For example, in Japanese Patent Application Laid-Open No. 57-73916, a circular core is provided by embedding a wound drum core in a resin molded body having a rectangular parallelepiped shape and providing terminal electrodes on both ends of the resin molded body. A structure corresponding to surface mounting is disclosed in which the problem of rolling property of parts is avoided. According to this structure, a wound inductor compatible with surface mounting can be obtained, but a drum core must be embedded in the resin molded body, resulting in a decrease in mass productivity and an increase in cost. Not only that, it is becoming difficult to adopt such a structure because of the downsizing of the wound inductor.
[0004]
An effective means for avoiding the above-described problems when a drum core having a circular collar portion is used is to make the collar portion square. Such a wound inductor is disclosed in, for example, Japanese Utility Model Laid-Open No. 61-144616.
[0005]
Japanese Patent Laid-Open No. 10-172853 discloses a manufacturing method in which a concave or convex portion is formed on the end face of a winding element body such as a quadrangular prism, and the winding element body is rotated around this as a center. Is disclosed.
[0006]
However, the manufacturing method disclosed in Japanese Patent Laid-Open No. 10-172853 is becoming unable to follow the progress of downsizing and higher precision of electronic components.
[0007]
One of the problems is the dimensional accuracy. For example, when forming a concave or convex part for centering on the end face of the winding element during molding, in the currently popular powder molding, the molded body is molded from the mold. When the mold is taken out, the molded body expands, and the formation position of the concave portion or the convex portion varies, which adversely affects the subsequent grinding. Or when forming a recessed part or a convex part as a post-process in a molded object, the production efficiency by the precision and man-hour of the processing process increasing becomes a problem. Further, the method of centering by supporting the concave portion or convex portion is also inferior in production efficiency and difficult to achieve stable mass production.
[0008]
Next, with respect to the method of performing grinding after the firing treatment, the position of the concave protrusion for centering varies due to the influence of deformation during firing and it is difficult to achieve high dimensional accuracy of grinding.
[0009]
As described above, in order to fully meet the current demands for downsizing, high accuracy, and stable mass production of electronic components, the introduction of highly productive equipment such as a coreless grinding machine was studied.
[0010]
However, the conventional coreless grinding apparatus cannot cope with a flange having an irregular shape or a small shape. The reason is that when the work (workpiece) is downsized, there are problems such as contact between the blade and grinding wheel, grinding wheel, etc., and sufficient rotational movement cannot be given to the work, or the work cannot be supported stably. This is because there is a problem.
[0011]
[Problems to be solved by the invention]
An object of the present invention is to provide a grinding blade, a grinding apparatus, and a grinding method capable of stably mass-producing a core member having a circular core and a non-circular rib from a non-circular core material with high dimensional accuracy. It is.
[0012]
[Means for Solving the Problems]
In order to solve the above-described problem, a grinding blade according to the present invention includes a blade base, a groove, a first inclined surface, a second inclined surface, and a third inclined surface. The groove is linearly provided on one surface of the blade base, and a front end opens at one end of the blade base.
[0013]
Each of the first and second inclined surfaces is disposed on both sides of the groove on the one end side of the blade base where the groove opens, and is inclined in the depth direction of the groove from the one surface of the blade base. is doing.
[0014]
The third inclined surface is located in front of the first and second inclined surfaces, and is inclined from the bottom surface of the groove in the same direction as the inclined direction of the first and second inclined surfaces. .
[0015]
The blade described above is combined with a grinding wheel and an adjustment wheel to constitute a grinding device. In the adjusting wheel, the outer periphery of the rotation faces the groove of the blade, and the width of the outer periphery of the rotation corresponds to the width of the groove. The grinding wheel has a rotating shaft parallel to the rotating shaft of the adjusting wheel and a rotating outer peripheral edge facing the rotating outer peripheral edge of the adjusting wheel. Located on the opposite side. The width of the rotating outer peripheral edge of the grinding wheel is substantially the same as the rotating outer peripheral edge of the adjusting wheel.
[0016]
In order to execute the grinding method according to the present invention using the above-described grinding apparatus, a core material having a non-circular cross section is provided at the tip of the blade located between the grinding wheel and the adjustment wheel of the grinding apparatus. Drop it. Next, the adjustment wheel is rotated, and the adjustment wheel is moved toward the groove.
[0017]
Since the adjusting wheel has a rotating outer peripheral edge facing the groove of the blade, when the adjusting wheel is moved toward the blade while rotating the adjusting wheel, the adjusting wheel keeps the rotating outer peripheral edge facing the groove, You will approach the core material.
[0018]
In addition, the blade includes first and second inclined surfaces, and each of the first and second inclined surfaces is disposed on both sides of the groove on one end side of the blade base in which the groove is opened. When the core material is dropped on the tip of the blade located between the grinding wheel and the adjustment wheel of the grinding apparatus, the core material is the first and first. 2 and is in contact with the rotating outer periphery of the adjusting wheel.
[0019]
Accordingly, when the adjusting wheel is rotated toward the blade while rotating, the adjusting wheel comes into contact with the core material. The rotation direction of the adjusting wheel is a direction in which the core material hangs up the first and second inclined surfaces.
[0020]
Since the core material has a non-circular cross section, the core material rolls on the first and second inclined surfaces with the distance from the center of rotation to the outer periphery as the rotation radius.
[0021]
As the adjustment wheel approaches the groove, the core material is pushed forward from the first and second inclined surfaces.
[0022]
A third inclined surface is located in front of the first and second inclined surfaces. Since the third inclined surface is inclined from the bottom surface of the groove in the same direction as the inclined direction of the first and second inclined surfaces, the contact rolling position of the core material is the first and second. It smoothly transitions from the inclined surface to the third inclined surface. The core material further receives a rotating action by the adjusting wheel while rolling on the third inclined surface.
[0023]
At this stage when the feeding operation of the winding core material by the adjusting wheel has progressed, the rotating outer peripheral edge of the adjusting wheel is located inside the groove and continues to rotate at that position.
[0024]
When the feeding action by the adjusting wheel further proceeds, the core material comes into contact with the grinding wheel. The grinding wheel is placed on the opposite side of the adjustment wheel, with the blade between them and the rotation axis is almost parallel to the rotation axis of the adjustment wheel, and the rotation outer peripheral edge faces the rotation outer periphery of the adjustment wheel. Is done. The width of the rotating outer peripheral edge of the grinding wheel is substantially the same as that of the adjusting wheel. Accordingly, the rotating outer peripheral edge of the grinding wheel is in a circular grinding portion and is in rotational contact with the core material. The grinding wheel rotates in the opposite direction to the adjustment wheel at the position of the blade.
[0025]
Then, after the adjustment wheel is driven to a predetermined cutting position, the adjustment wheel is moved backward to take out the ground core material. This core material has a shape in which both end sides preserve the original non-circular shape and the intermediate portion is ground into a circular shape. When the original non-circular shape is a square shape, a winding core member having a square-shaped collar portion on both sides and a circular cross-sectional portion in the middle portion, specifically, a drum core or the like is obtained.
[0026]
According to the above-described grinding method, the core material can be ground by the coreless grinding method, so that it is not necessary to form a concave portion or a convex portion for centering on the core material. For this reason, the dimensional accuracy, the production efficiency, and the difficulty of stable mass production due to the variation in the formation position of the concave portion or the convex portion are not accompanied.
[0027]
In addition, even when the core material is downsized, the core material can be provided with sufficient rotational motion, stably supported, and high-precision grinding can be performed.
[0028]
Other objects, configurations and advantages of the present invention will be described more specifically with reference to the drawings. The figure is merely illustrative.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
<Blade>
FIG. 1 is a perspective view of a grinding blade according to the present invention, and FIG. 2 is an enlarged perspective view showing a tip portion of the grinding blade shown in FIG. The illustrated grinding blade includes a blade base 11, a groove 12, a first inclined surface 131, a second inclined surface 132, and a third inclined surface 133. The blade base 11 is made of a high hardness metal or alloy.
[0030]
The groove 12 is linearly provided on one surface of the blade base 11, and the front end opens at one end of the blade base 11. In the embodiment, the groove 12 is formed over the entire length of the blade base 11 while maintaining a constant width W0 (see FIG. 2), and is open at both ends of the blade base 11.
[0031]
Each of the first and second inclined surfaces 131 and 132 is disposed on both sides of the groove 12 on one end side of the blade base 11 where the groove 12 opens, and faces one end of the blade base 11 to face one surface of the blade base 11. To the depth direction of the groove 12. The inclination angle θ of the first and second inclined surfaces 131 and 132 can be set, for example, in the range of 25 to 60 °. The first inclined surface 131 is formed by inclining the leading edge of the front portion 111 of the blade base 11, and the second inclined surface 132 is the distal end of the second front piece 110 that extends narrowly across the groove 12. It is formed by tilting the edge.
[0032]
The third inclined surface 133 is located in front of the first and second inclined surfaces 131 and 132, and is the same direction as the inclined direction of the first and second inclined surfaces 131 and 132 from the bottom surface 121 of the groove 12. It is inclined to. The first to third inclined surfaces 131 to 133 are preferably formed so as to be substantially on the same plane.
[0033]
In the illustrated embodiment, the blade base 11 includes a first end surface 141 and a second end surface 142. The first end surface 141 is an end surface that terminates the first inclined surface 131, and is separated from the end of the third inclined surface 133 by a distance d <b> 1. The second end surface 142 is an end surface that terminates the second inclined surface 132, and is separated from the terminal end of the third inclined surface 133 by a distance d1.
[0034]
Further, the embodiment includes a first side wall surface 151. The first side wall surface 151 is erected on the side portion of the first inclined surface 131. A hole 16 is provided in the main surface of the blade base 11. The hole 16 is used as a mounting hole.
[0035]
The rear portion 114 provided with the attachment hole 16 of the blade base body 11 is thicker than the first front piece 111 and is connected to the first front piece 111 via the inclined surfaces 112 and 113.
[0036]
<Grinding machine>
3 is a diagram schematically showing a configuration of a grinding apparatus according to the present invention, FIG. 4 is an enlarged plan view showing a blade arrangement portion of the grinding apparatus shown in FIG. 3, and FIG. 5 is an arrangement shown in FIG. It is a front fragmentary sectional view. The illustrated grinding device is a kind of a centerless grinding device, and includes a blade 2, an adjustment wheel 3, and a grinding wheel 4.
[0037]
The blade 2 is the blade according to the present invention shown in FIGS. 1 and 2. The blade 2 is disposed between the adjustment wheel 3 and the grinding wheel 4, and the rear portion 114 of the blade base 11 is fixed to the fixed body 5. The adjusting wheel 3 and the grinding wheel 4 are components that are normally provided in a centerless grinding apparatus.
[0038]
The adjusting wheel 3 has an outer peripheral portion made of diamond electrodeposition, metal bond diamond, or the like. The adjustment wheel 3 is rotated by a motor (not shown) in the direction of the arrow a1 (clockwise in the drawing) from the rear end to the front end of the blade 2. The rotational speed is an example, but is about 15 to 40 rpm. As the advance / retreat drive mechanism of the adjustment wheel 3, one known in a conventional centerless grinding apparatus can be used.
[0039]
As shown in FIG. 4, the adjusting wheel 3 has a rotating outer peripheral edge 31 facing the groove 12 of the blade 2, and the adjusting wheel 3 can advance and retreat with respect to the groove 12 in the directions of arrows F <b> 1 and F <b> 2. . The width W1 of the rotation outer peripheral edge 31 corresponds to the width W0 of the groove 12. More specifically, the width W1 is slightly smaller than the width W0 of the groove 12.
[0040]
As for the grinding wheel 4, the rotation outer periphery 41 is comprised with the metal bond diamond etc. with grinding power. The grinding wheel 4 is driven to rotate at, for example, 4000 to 8000 rpm by a motor (not shown). The rotation direction b1 is clockwise.
[0041]
The grinding wheel 4 has the blade 2 in between, the rotational axis O2 is substantially parallel to the rotational axis O1 of the adjustment wheel 3, and the rotation outer peripheral edge 41 is opposed to the rotation outer peripheral edge 31 of the adjustment wheel 3. It is arranged on the side opposite to the adjusting wheel 3. Actually, the rotation axis O1 of the adjustment wheel 3 makes an angle of 0 to 3 ° with respect to the rotation axis O2 of the grinding wheel 4. By giving such a small angle, a rotational force is applied to the member to be ground, and a force for pressing the member to be ground against the blade 2 is generated, so that lateral displacement of the member to be ground can be suppressed. The width W2 of the rotating outer peripheral edge 41 of the grinding wheel 4 is substantially the same as or slightly larger than the width W1 of the rotating outer peripheral edge 31 of the adjusting wheel 3.
[0042]
In the illustrated embodiment, the position of the line segment O12 connecting the rotation axes O1 and O2 of the adjustment wheel 3 and the grinding wheel 4 is lower than the end of the third inclined surface 133 of the blade 2 by a height h1 ( (See FIG. 5).
[0043]
<Grinding method for non-circular core material>
Next, a grinding method using the grinding apparatus shown in FIGS. 3 to 5 will be described with reference to FIGS. First, as shown in FIGS. 6 and 7, the core material 6 having a non-circular cross section is set at the tip of the blade 2 positioned between the grinding wheel 4 and the adjustment wheel 3 of the grinding apparatus. A typical example of the winding core material 6 is a ferrite member having a rectangular cross section. Such a ferrite member is used for making a drum core of a wound inductor.
[0044]
Next, the adjusting wheel 3 is rotated toward the groove 12 in the direction indicated by the arrow F1. The adjustment wheel 3 rotates around the rotation axis O1 in the direction indicated by the arrow a1. At this timing, the grinding wheel 4 is already rotating.
[0045]
Since the adjustment outer periphery 31 of the adjustment wheel 3 faces the groove 12 of the blade 2, when the adjustment wheel 3 is moved toward the blade 2 while rotating, the adjustment wheel 3 has the rotation outer edge 31 of the groove 2. At the position facing 12, the core material 6 is approached.
[0046]
In addition, the blade 2 includes first and second inclined surfaces 131 and 132, and each of the first and second inclined surfaces 131 and 132 is provided at one end side of the blade base 11 where the groove 12 opens. Since it is disposed on both sides of the groove 12 and is inclined in the depth direction of the groove 12 from one surface of the blade base 11, the winding core material 6 is placed at the tip of the blade 2 positioned between the grinding wheel 4 and the adjustment wheel 3. When set, the core material 6 is received by the first and second inclined surfaces 131, 132 and contacts the rotation outer peripheral edge 31 of the adjustment wheel 3.
[0047]
Accordingly, when the adjusting wheel 3 is moved toward the blade 2 while rotating the adjusting wheel 3, the adjusting wheel 3 contacts the core material 6 and rotates it. The rotation direction a1 of the adjusting wheel 3 is a direction in which the winding core material 6 hangs up the first and second inclined surfaces 131 and 132 by the rotational force.
[0048]
Since the core material 6 has a non-circular cross-section, the core material 6 has the direction indicated by the arrow C1 on the first and second inclined surfaces 131 and 132 with the distance from the rotation center to the outer periphery as the rotation radius. (See FIG. 7).
[0049]
As shown in the illustrated embodiment, the first end surface 141 that terminates the first inclined surface 131 and the second end surface 142 that terminates the second inclined surface 132 are connected to the start end of the third inclined surface 133. Since the distance d1 is separated from each other, the core material 6 can rotate through the space created by the distance d1.
[0050]
In the case of the embodiment, since the first side wall surface 151 is erected on the side portion of the first inclined surface 131, one end surface of the winding core material 6 in the rotation axis direction is the first side wall surface 151. Pressed by. For this reason, the movement of the winding core material 6 in the rotation axis direction is restricted by the first side wall surface 151, and the winding core material 6 is subjected to the rotating action by the adjusting wheel 3 at a substantially constant position.
[0051]
The groove 12 of the blade 2 faces the rotating outer peripheral edge 31 of the adjusting wheel 3, and the adjusting wheel 3 has a winding core because the width W 1 of the rotating outer peripheral edge 31 corresponds to the width W 0 (see FIG. 4) of the groove 12. A rotation action is given to the intermediate portion of the material 6 with the width W1 of the rotation outer peripheral edge 31 of the adjustment wheel 3, and a circular grinding portion 161 is generated.
[0052]
As the adjustment wheel 3 approaches the groove 12, the core material 6 is pushed forward from the first and second inclined surfaces 131 and 132 toward the front thereof.
[0053]
A third inclined surface 133 is located in front of the first and second inclined surfaces 131 and 132. Since the third inclined surface 133 is inclined from the bottom surface of the groove 12 in the same direction as the inclined directions of the first and second inclined surfaces 131 and 132, the contact rolling position of the core material 6 is the same. The first and second inclined surfaces 131 and 132 smoothly transition to the third inclined surface 133. Further, the core material 6 is subjected to rotation and grinding feed action by the adjusting wheel 3 while rolling on the third inclined surface 133. At this stage when the winding core material 6 has been ground, the rotating outer peripheral edge 31 of the adjusting wheel 3 is located inside the groove 12 and continues to rotate at that position.
[0054]
When the grinding of the core material 6 further proceeds, as shown in FIGS. 8 and 9, the core material 6 includes a grinding portion 161 having a rotating outer peripheral edge 31 of the adjusting wheel 3, a rotating outer peripheral edge 41 of the grinding wheel 4, and the like. It comes in contact with the third inclined surface 133. The grinding wheel 4 has the blade 2 in between, the rotational axis O2 is substantially parallel to the rotational axis O1 of the adjustment wheel 3, and the rotation outer peripheral edge 41 is opposed to the rotation outer peripheral edge 31 of the adjustment wheel 3. It is arranged on the side opposite to the adjusting wheel 3. The width W2 of the rotating outer peripheral edge 41 of the grinding wheel 4 is substantially the same as or slightly larger than the width W1 of the rotating outer peripheral edge 31 of the adjusting wheel 3. Therefore, the rotating outer peripheral edge 41 of the grinding wheel 4 is in rotational contact with the core material 6 and is ground to form a circular grinding portion 161. The rotation direction b1 of the grinding wheel 4 is opposite to the rotation direction a1 of the adjustment wheel 3 with respect to the core material 6.
[0055]
Then, the winding core material 6 is driven to the predetermined cutting position by the adjusting wheel 3, and the adjusting wheel 3 is retracted in the direction indicated by the arrow F2 before the rotating outer peripheral edge 31 contacts the bottom surface of the groove 12, and is ground. The wound core material 6 is taken out. The winding core material 6 has a shape in which both ends 162 and 163 retain the original non-circular shape and the intermediate portion 161 is ground into a circular shape. When the original shape of the core material 6 is a square shape, a core member having square-shaped flange portions 162 and 163 on both sides and a circular cross-sectional portion 161 on the middle portion, specifically, a drum core or the like can get.
[0056]
According to the above-described grinding method, the core material 6 can be ground by the coreless grinding method, so that it is not necessary to form a concave portion or a convex portion for centering on the core material 6. For this reason, there is no reduction in dimensional accuracy due to variations in the formation positions of the concave portions or convex portions, and there is no reduction in production efficiency or difficulty in stable mass production.
[0057]
Further, even when the core material 6 is downsized, the core material 6 can be provided with a sufficient rotational motion, stably supported, and high-precision grinding can be performed.
[0058]
<Other embodiments>
FIG. 10 is a perspective view showing another embodiment of the grinding blade according to the present invention, and FIG. 11 is an enlarged view of the tip portion of the grinding blade shown in FIG. In the figure, the same components as those shown in FIGS. 1 and 2 are denoted by the same reference numerals, and redundant description is omitted. The feature of this embodiment is that the first side wall surface 151 and the second side wall surface 152 are included. The second side wall surface 152 is erected on the side portion of the second inclined surface 132. With such a structure, both ends of the non-circular core material can be pressed by the first side wall surface 151 and the second side wall surface 152, so the rotation axis of the core material during the grinding process Movement in the direction can be further reliably suppressed.
[0059]
The rear end portion 116 of the blade base body 11 has a thickness changed stepwise from the intermediate portion 115 whose thickness has been increased, and a mounting hole 16 is provided in the rear end portion 116.
[0060]
FIG. 12 is a perspective view showing another embodiment of the grinding blade according to the present invention. In the figure, the same components as those shown in FIG. 1, FIG. 2, FIG. 10, and FIG. The feature of this embodiment is that the front edge of the first front piece 111 constituting the blade base 11 is chamfered to form the first inclined surface 131 and is partitioned from the first front piece 111 by the groove 12. That is, the second inclined surface 132 is formed by chamfering the leading edge of the second front piece 110. The side end surfaces of the first and second front pieces 111 and 110 are used as the first and second end surfaces 141 and 142. In this embodiment, the first side wall surface 151 shown in FIGS. 1 and 2 and the first and second side wall surfaces 151 and 152 shown in FIGS. 10 and 11 are not provided. In application, it is preferable to arrange a member that changes to the first side wall surface or the second side wall surface.
[0061]
13 is a front view showing a part of another embodiment of the grinding blade according to the present invention, FIG. 14 is a side view of the grinding blade shown in FIG. 13, and FIG. 15 is the grinding shown in FIGS. FIG. In the figure, the same reference numerals are given to the same components as those shown in the above-mentioned drawings, and the duplicated explanation is omitted. The feature of this embodiment is that the first inclined surface 131 and the second inclined surface 132 are arranged so as to form an inclined surface that is substantially continuous with the third inclined surface 133.
[0062]
Although not shown, the grinding blade shown in FIGS. 10 to 15 is also used in the state shown in FIGS. 3 to 6 and used for grinding the non-circular core material shown in FIGS. Is done.
[0063]
【The invention's effect】
As described above, according to the present invention, a grinding blade, a grinding device, and a grinding device capable of stably mass-producing a core member having a circular core and a non-circular ridge with high dimensional accuracy from a non-circular core material. A grinding method can be provided.
[Brief description of the drawings]
FIG. 1 is a perspective view of a grinding blade according to the present invention.
2 is an enlarged perspective view showing a tip portion of the grinding blade shown in FIG. 1. FIG.
FIG. 3 is a diagram schematically showing a configuration of a grinding apparatus according to the present invention.
4 is an enlarged plan view showing a blade arrangement portion of the grinding apparatus shown in FIG. 3. FIG.
FIG. 5 is a partial front sectional view of the arrangement shown in FIG. 4;
FIG. 6 is a plan view for explaining a grinding method according to the present invention.
7 is a partial cross-sectional view of the arrangement shown in FIG. 6 as viewed from the front. FIG.
8 is a plan view showing a step advanced from the steps shown in FIGS. 6 and 7. FIG.
FIG. 9 is a partial cross-sectional view of the arrangement shown in FIG. 8 as viewed from the front.
FIG. 10 is a perspective view showing another embodiment of a grinding blade according to the present invention.
11 is an enlarged view of a tip portion of the grinding blade shown in FIG.
FIG. 12 is a perspective view showing another embodiment of a grinding blade according to the present invention.
FIG. 13 is a front view showing a part of another embodiment of a grinding blade according to the present invention.
14 is a side view of the grinding blade shown in FIG. 13. FIG.
15 is an enlarged perspective view of the grinding blade shown in FIGS. 13 and 14. FIG.
[Explanation of symbols]
11 Blade base 12 Groove 131 First inclined surface 132 Second inclined surface 133 Third inclined surface 141 First end surface 142 Second end surface 151 First side wall surface

Claims (9)

A grinding blade including a blade base, a groove, a first inclined surface, a second inclined surface, and a third inclined surface,
The groove is provided linearly on one surface of the blade base, and a front end is opened at one end of the blade base,
Each of the first and second inclined surfaces is disposed on both sides of the groove on the one end side of the blade base where the groove opens, and is inclined in the depth direction of the groove from the one surface of the blade base. And
The third inclined surface is located in front of the first and second inclined surfaces, and is inclined from the bottom surface of the groove in the same direction as the inclined direction of the first and second inclined surfaces. blade. The blade according to claim 1, comprising a first end face and a second end face,
The first end surface is an end surface that terminates the first inclined surface, and is spaced apart from a starting end of the third inclined surface;
The second end surface is an end surface that terminates the second inclined surface, and is a blade spaced apart from a starting end of the third inclined surface. The blade according to claim 1 , wherein the blade includes a first side wall surface , and the first side wall surface is erected on a side portion of the first inclined surface. 4. The blade according to claim 3, wherein the blade includes a second side wall surface , and the second side wall surface is erected on a side portion of the second inclined surface. 5.   5. The blade according to claim 1, wherein the first to third inclined surfaces are substantially located on the same plane. A grinding apparatus including a blade, a grinding wheel, and an adjustment wheel,
The blade is described in any one of claims 1 to 5,
The adjustment wheel has a rotating outer peripheral edge facing the groove of the blade, and a width of the rotating outer peripheral edge corresponds to a width of the groove;
The grinding wheel has a rotating shaft parallel to the rotating shaft of the adjusting wheel and a rotating outer peripheral edge facing the rotating outer peripheral edge of the adjusting wheel. A grinding apparatus that is disposed on the opposite side and has a rotation outer peripheral edge substantially the same width as the rotation outer peripheral edge of the adjusting wheel.   The grinding apparatus according to claim 6, wherein the blade is disposed at a position where the groove receives a rotation outer peripheral edge of the adjusting wheel.   8. The grinding apparatus according to claim 6, wherein a rotating shaft of the adjusting wheel and the grinding wheel is lower than a terminal end of the third inclined surface of the blade. A grinding method using a grinding device to form a core member having a circular cross-section in the middle of a non-circular core material,
The grinding apparatus is the one described in any one of claims 6 to 8,
The core material having a non-circular cross-section is set at the tip of the blade located between the grinding wheel and the adjustment wheel of the grinding device,
Rotate the adjustment wheel,
A grinding method including the step of causing the adjustment wheel to approach the groove.

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