Blade sharpening device

Abstract

The present invention provides a cutting tool sharpening device that allows for relatively easy adjustment of the grinding angle of the cutting edge. [Solution] The rotary polishing tool 11 is disc-shaped and is provided so that the cutting edge portion 1a of the rotary blade 1 can be polished with its circumferential surface 11a. The polishing tool rotation support portion 12 supports the rotary polishing tool 11 and is provided so that the rotary polishing tool 11 can be rotatably mounted on it. The rotary blade mounting portion 13 is detachable from the rotary blade 1, and when the rotary blade 1 is mounted, a vertical surface perpendicular to the central axis of the rotary polishing tool 11 is provided so that it is parallel to the central axis of the rotary blade 1, and a surface parallel to that vertical surface and containing the central axis of the rotary blade 1 crosses the circumferential surface 11a of the rotary polishing tool 11 along the circumferential direction. The rotary blade mounting portion 13 is provided so that the mounted rotary blade 1 can be rotatably mounted on it. The moving mechanism 14 is able to move the rotary blade mounting portion 13 two-dimensionally along the vertical surface so that the circumferential surface 11a of the rotary polishing tool 11 is in contact with the cutting edge portion 1a of the rotary blade 1 mounted on the rotary blade mounting portion 13.

Description

Technical Field

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[0001] The present invention relates to a tool grinding device.

Background Art

[0002] Conventionally, as a tool grinding device for grinding the cutting edge of a rotary blade to remove burrs and burrs, etc., it has a rotary grindstone attached to a grinder support provided on a pedestal so as to rotate vertically, and a rotary blade support provided on the pedestal. The rotary blade is placed horizontally on the rotary blade support and rotated horizontally, and the grinding surface of the rotary grindstone is applied to the cutting edge of the rotary blade. A rotary blade grinding device for a lawn mower (for example, see Patent Document 1), or a workpiece support for buffing a rotary cutting blade by bringing a horizontally rotated rotary cutting blade into contact with a working tool such as a grinder attached so as to rotate vertically (for example, see Patent Document 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional tool grinding device described in Patent Document 1 or 2, since the rotary blade attached to the rotary blade support or the workpiece support can only be moved in the horizontal direction, it is difficult to change the angle at which the rotary grindstone or grinder contacts the cutting edge of the rotary blade attached to each support, and there is a problem that it is difficult to adjust the angle of the cutting edge after grinding (hereinafter referred to as the "grinding angle").

[0005] The present invention has been made paying attention to such problems, and an object thereof is to provide a tool grinding device capable of relatively easily adjusting the grinding angle of the cutting edge. [Means for solving the problem]

[0006] To achieve the above objective, the blade sharpening apparatus according to the present invention is a blade sharpening apparatus for sharpening a cutting edge portion of a rotating blade that is tapered from the tip of the peripheral edge toward the central axis, and is characterized by comprising: a rotating sharpening tool having a disc shape having a predetermined thickness and provided to be able to sharpen the cutting edge portion of the rotating blade at least on its circumferential surface; a sharpening tool rotation support part that supports the rotating sharpening tool and rotates the rotating sharpening tool about its central axis; a rotating blade mounting part to which the rotating blade can be attached and detached, wherein when the rotating blade is attached, a vertical surface perpendicular to the central axis of the rotating sharpening tool is parallel to the central axis of the rotating blade, and a surface parallel to the vertical surface and including the central axis of the rotating blade is provided so as to cross the circumferential surface of the rotating sharpening tool along the circumferential direction, and the attached rotating blade rotates about its central axis; and a moving mechanism that moves the rotating blade mounting part two-dimensionally along the vertical surface so that the circumferential surface of the rotating sharpening tool contacts the cutting edge portion of the rotating blade attached to the rotating blade mounting part.

[0007] The blade sharpening apparatus according to the present invention can sharpen the blade edge in the following manner. First, the rotating blade is attached to the rotating blade mounting part, the rotating sharpening tool is rotated by the sharpening tool rotation support part, and the rotating blade is rotated by the rotating blade mounting part. Next, the rotating blade mounting part is moved by the moving mechanism, and the blade edge of the rotating blade is brought into contact with the circumferential surface of the rotating sharpening tool. At this time, the rotating blade mounting part is provided such that a vertical plane perpendicular to the central axis of the rotating sharpening tool is parallel to the central axis of the rotating blade, and a plane parallel to that vertical plane and containing the central axis of the rotating blade crosses the circumferential surface of the rotating sharpening tool along the circumferential direction. Therefore, the part of the blade edge along the periphery of the rotating blade that is closest to the rotating sharpening tool can be brought into contact with the circumferential surface of the rotating sharpening tool. In this way, the blade edge of the rotating blade can be sharpened on at least the circumferential surface of the rotating sharpening tool, and chips, burrs, etc. on the blade edge can be removed.

[0008] The blade sharpening apparatus according to the present invention allows the rotating blade mounting portion to be moved two-dimensionally along a vertical plane perpendicular to the central axis of the rotating sharpening tool by a moving mechanism, so that the position in which the rotating blade contacts the circumferential surface of the rotating sharpening tool can be easily adjusted. As a result, the angle at which the circumferential surface of the rotating sharpening tool contacts the cutting edge of the rotating blade can be easily changed, and the grinding angle of the cutting edge can be adjusted relatively easily.

[0009] In the blade sharpening apparatus according to the present invention, the cutting edge of the rotating blade may be brought into contact with the circumferential surface of the rotating sharpening tool after the rotating sharpening tool and the rotating blade have been rotated, or the rotating sharpening tool and the rotating blade may be rotated after the cutting edge of the rotating blade has been brought into contact with the circumferential surface of the rotating sharpening tool. Furthermore, in the blade sharpening apparatus according to the present invention, the rotation of the rotating sharpening tool and the rotating blade is such that a vertical plane perpendicular to the central axis of the rotating sharpening tool is parallel to the central axis of the rotating blade, and the rotation of the rotating sharpening tool and the rotating blade may be vertical rotation, horizontal rotation, or rotation within an inclined plane, respectively.

[0010] In the blade sharpening apparatus according to the present invention, the moving mechanism may be configured to move the rotating blade mounting portion along two non-parallel lines in a vertical plane perpendicular to the central axis of the rotating sharpening tool. In this case, for example, the sharpening tool rotation support portion may be configured to rotate the rotating sharpening tool vertically, the rotating blade mounting portion may be configured to rotate the rotating blade horizontally, and the moving mechanism may be configured to move the rotating blade mounting portion horizontally and vertically along the vertical plane. Furthermore, the moving mechanism may be configured to allow the rotating blade mounting portion to rotate along its vertical plane.

[0011] In the blade sharpening apparatus according to the present invention, it is preferable that the moving mechanism is capable of moving the rotating blade mounting portion so that the contact angle is a desired angle, when the angle between the tangent to the circumferential surface and the surface of the cutting edge portion at the contact position is defined as the contact angle in a cross section along the vertical plane passing through the contact position between the circumferential surface and the cutting edge portion of the rotating sharpening tool. In this case, the grinding angle of the cutting edge portion can be adjusted by moving the rotating blade mounting portion with the moving mechanism and controlling the contact angle. Furthermore, this makes it possible to set the grinding angle to the contact angle or an angle close to the contact angle, thereby obtaining a desired grinding angle.

[0012] When considering the cutting performance of the rotary blade, it is preferable for the contact angle to be as small as possible and the cutting edge to be sharp. However, when considering the grinding time, a larger contact angle is preferable. Therefore, considering the balance between cutting performance and grinding time, the contact angle is preferably 3° to 15°, and particularly preferably 4° to 11°.

[0013] In the blade sharpening apparatus according to the present invention, the moving mechanism may be configured to maintain a constant contact angle while the rotating sharpening tool is rotated by the sharpening tool rotation support part and the rotating blade is rotated by the rotating blade mounting part (during sharpening). Furthermore, even during sharpening, the moving mechanism may be configured to adjust the position in which the rotating blade contacts the circumferential surface of the rotating sharpening tool by moving the rotating blade mounting part according to the sharpening status of the rotating blade.

[0014] In the blade sharpening apparatus according to the present invention, the moving mechanism may be capable of automatically moving the rotating blade mounting portion so that the contact angle becomes a preset angle based on the radius of the rotating blade and the angle between a plane perpendicular to the central axis of the rotating blade and the surface of the cutting edge portion. In this case, for example, the rotating blade mounting portion can be moved automatically by the following principle.

[0015] As shown in FIGS. 1(a) and (b), in a cross-section parallel to the vertical plane perpendicular to the central axis of the rotary abrasive tool and including the central axis of the rotary blade, let the radius of the rotary blade be r, the angle formed by the plane perpendicular to the central axis of the rotary blade and the surface of the blade tip (hereinafter referred to as the "blade angle") be θ1, and the contact angle be θ2. Taking the contact point between the circumferential surface of the rotary abrasive tool and a straight line perpendicular to the central axis of the rotary blade as the origin, the straight line perpendicular to the central axis of the rotary blade as the x-axis, and the straight line passing through the origin and the central axis of the rotary abrasive tool as the z-axis.

[0016] At this time, first, as shown in FIG. 1(a), when the contact angle θ2 is zero, that is, when the circumferential surface of the rotary abrasive tool is in contact with the surface of the blade tip, if the x-coordinate of the contact point is x1 and the z-coordinate is z1, then x1 and z1 are represented by equations (1) and (2) respectively.

[0017]

Equation

[0018] Next, as shown in FIG. 1(b), when the contact angle θ2 is θ2 > 0, if the x-coordinate of the contact point between the circumferential surface of the rotary abrasive tool and the surface of the blade tip is x2 and the z-coordinate is z1 + z2, then x2 and z1 + z2 are represented by equations (3) and (4) respectively. Also, θ2 is represented by equation (5).

[0019]

Equation

[0020] Thus, by setting the contact angle θ2, using the previously known r and θ1, the coordinates of the contact point between the circumferential surface of the rotary abrasive tool and the surface of the blade tip can be obtained from equations (3) and (4). By automatically moving the rotary blade mounting portion by the moving mechanism so that the surface of the blade tip is located at the obtained coordinates, the blade tip of the rotary blade can be polished at the desired contact angle θ2.

Advantages of the Invention

[0021] According to the present invention, it is possible to provide a cutting tool polishing apparatus capable of relatively easily adjusting the grinding angle of the cutting edge portion.

Brief Description of the Drawings

[0022] [Figure 1] It is a cross-sectional view passing through the contact position between the rotary abrasive tool and the rotary blade when (a) the peripheral surface of the rotary abrasive tool contacts the surface of the cutting edge portion of the rotary blade (when the contact angle is zero), and (b) the peripheral surface of the rotary abrasive tool contacts the surface of the cutting edge portion of the rotary blade at a contact angle θ2, according to the cutting tool polishing apparatus of the present invention. [Figure 2] It is a perspective view showing a cutting tool polishing apparatus according to an embodiment of the present invention. [Figure 3] It is a side view showing a cutting tool polishing apparatus according to an embodiment of the present invention. [Figure 4] It is a plan view showing a cutting tool polishing apparatus according to an embodiment of the present invention. [Figure 5] It is a plan view showing (a) a part (half) of a rotary blade before polishing having a defect with a part of the cutting edge portion chipped, and (b) a part (half) of the rotary blade after polishing in which the defect is corrected to a state almost without chipping, in an experiment for polishing the cutting edge portion of the rotary blade of the cutting tool polishing apparatus according to an embodiment of the present invention. [Figure 6] It is a table showing the results of an experiment for polishing the cutting edge portion of the rotary blade of the cutting tool polishing apparatus according to an embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0023] Hereinafter, embodiments of the present invention will be described based on the drawings. FIGS. 2 to 6 show a cutting tool polishing apparatus according to an embodiment of the present invention. As shown in FIGS. 2 to 4, the cutting tool polishing apparatus 10 is configured to polish the cutting edge portion 1a of the rotary blade 1, and includes a rotary abrasive tool 11, an abrasive tool rotation support portion 12, a rotary blade attachment portion 13, and a movement mechanism 14.

[0024] The rotating blade 1 is shaped like a thin disc, and a cutting edge portion 1a is formed on the peripheral edge of one or both of its surfaces. The cutting edge portion 1a is tapered from the tip of the peripheral edge of the rotating blade 1 toward the central axis, so that the tip of the peripheral edge of the rotating blade 1 is pointed.

[0025] The rotary polishing tool 11 consists of, for example, a buff or grinder, and has a disc shape with a predetermined thickness. The rotary polishing tool 11 is provided so that the cutting edge portion 1a of the rotary blade 1 can be polished with at least its circumferential surface 11a.

[0026] The polishing tool rotation support unit 12 includes a rotary motor 12a and a rotary shaft portion 12b that protrudes from the rotary motor 12a and is rotatably mounted by the rotary motor 12a. The tip of the rotary shaft portion 12b is attached to the center of the rotating polishing tool 11. As a result, the polishing tool rotation support unit 12 supports the rotating polishing tool 11 and, together with the rotary shaft portion 12b, rotates the rotating polishing tool 11 around its central axis using the rotary motor 12a. Furthermore, the polishing tool rotation support unit 12 is capable of controlling the rotation speed of the rotating polishing tool 11. In a specific example shown in Figures 2 to 4, the polishing tool rotation support unit 12 is configured to rotate the rotating polishing tool 11 vertically.

[0027] The rotating blade mounting section 13 has a rotating motor 13a and is equipped with a rotating blade 1 that can be attached and detached. When the rotating blade 1 is attached to the rotating blade mounting section 13, the rotating motor 13a allows the rotating blade 1 to rotate around its central axis. The rotating blade mounting section 13 is capable of controlling the rotational speed of the rotating blade 1. In a specific example shown in Figures 2 to 4, the rotating blade mounting section 13 is equipped to rotate the rotating blade 1 horizontally with the cutting edge portion 1a facing upwards.

[0028] Furthermore, the rotating blade mounting section 13 is provided such that when the rotating blade 1 is attached, a predetermined vertical surface perpendicular to the central axis of the rotating polishing tool 11 (hereinafter referred to as the "reference vertical surface") is parallel to the central axis of the rotating blade 1, and a surface parallel to the reference vertical surface and containing the central axis of the rotating blade 1 crosses the circumferential surface 11a of the rotating polishing tool 11 along the circumferential direction. The blade sharpening device 10 may be configured so that the positional relationship between the rotating blade 1 and the rotating polishing tool 11 is such that when the rotating blade 1 is attached to the rotating blade mounting section 13, or the rotating blade mounting section 13 or the polishing tool rotation support section 12 may be configured to be movable so that the positional relationship is such that after the rotating blade 1 is attached to the rotating blade mounting section 13.

[0029] The moving mechanism 14 supports the rotating blade mounting portion 13 and is provided to allow the rotating blade mounting portion 13 to move two-dimensionally, either automatically or manually, along a reference vertical plane. This allows the moving mechanism 14 to move the rotating blade mounting portion 13 so that the cutting edge portion 1a of the rotating blade 1 attached to the rotating blade mounting portion 13 contacts the circumferential surface 11a of the rotating polishing tool 11. In a specific example shown in Figures 2 to 4, the moving mechanism 14 is configured to slide the rotating blade mounting portion 13 horizontally and vertically along a reference vertical plane.

[0030] Furthermore, the moving mechanism 14 is capable of moving the rotating blade mounting portion 13 so that the contact angle (the angle between the tangent to the circumferential surface 11a of the rotating polishing tool 11 and the surface of the cutting edge portion 1a of the rotating blade 1, in a cross-section parallel to the reference vertical plane and passing through the contact point between the circumferential surface 11a of the rotating polishing tool 11 and the cutting edge portion 1a of the rotating blade 1) at that contact point becomes a desired angle. In a specific example shown in Figures 2 to 4, the moving mechanism 14 is capable of moving the rotating blade mounting portion 13 so that the circumferential surface 11a of the rotating polishing tool 11 and the cutting edge portion 1a of the rotating blade 1 come into contact below the central axis of the rotating polishing tool 11. In addition, the moving mechanism 14 is capable of automatically moving the rotating blade mounting portion 13 so that the contact angle becomes a preset angle between 3° and 15°, based on the principle shown in Figure 1 and equations (1) to (5).

[0031] The moving mechanism 14 may be configured to maintain a constant contact angle while the rotating polishing tool 11 is rotated by the polishing tool rotation support part 12 and the rotating blade 1 is rotated by the rotating blade mounting part 13 (during polishing). Alternatively, the moving mechanism 14 may be configured to automatically adjust the position in which the cutting edge portion 1a of the rotating blade 1 contacts the circumferential surface 11a of the rotating polishing tool 11, even during polishing, by moving the rotating blade mounting part 13 according to the polishing status of the rotating blade 1.

[0032] In a specific example shown in Figures 2 to 4, the blade sharpening device 10 is configured such that the rotating sharpening tool 11 is rotated at 100 to 2000 rpm by the sharpening tool rotation support section 12, and the rotating blade 1 is rotated at 50 to 500 rpm by the rotating blade mounting section 13. Furthermore, the blade sharpening device 10 is configured such that the rotation direction of the rotating sharpening tool 11 by the sharpening tool rotation support section 12 is from the surface side of the cutting edge portion 1a of the rotating blade 1 to be sharpened toward the opposite surface side.

[0033] Next, I will explain the mechanism of action. The blade sharpening device 10 can sharpen the blade tip 1a in the following manner. First, the rotating blade 1 is attached to the rotating blade mounting part 13, the rotating sharpening tool 11 is rotated by the sharpening tool rotation support part 12, and the rotating blade 1 is rotated by the rotating blade mounting part 13. Next, the rotating blade mounting part 13 is moved by the moving mechanism 14, and the blade tip 1a of the rotating blade 1 is brought into contact with the circumferential surface 11a of the rotating sharpening tool 11. At this time, the rotating blade mounting part 13 is provided such that the reference vertical plane is parallel to the central axis of the rotating blade 1, and the plane parallel to the reference vertical plane and containing the central axis of the rotating blade 1 crosses the circumferential surface 11a of the rotating sharpening tool 11 along the circumferential direction. Therefore, the part of the blade tip 1a along the periphery of the rotating blade 1 that is closest to the rotating sharpening tool 11 can be brought into contact with the circumferential surface 11a of the rotating sharpening tool 11. In this way, the cutting edge portion 1a of the rotating blade 1 can be polished with the circumferential surface 11a of the rotating polishing tool 11, and chips, burrs, etc. can be removed from the cutting edge portion 1a.

[0034] The blade sharpening device 10 allows the rotating blade mounting portion 13 to be moved two-dimensionally along a reference vertical plane by the moving mechanism 14, so that the position in which the rotating blade 1 contacts the circumferential surface 11a of the rotating sharpening tool 11 can be easily adjusted. This makes it easy to change the contact angle between the circumferential surface 11a of the rotating sharpening tool 11 and the cutting edge portion 1a of the rotating blade 1, and thus the grinding angle of the cutting edge portion 1a can be adjusted relatively easily. Furthermore, this makes it possible to obtain a desired grinding angle that is at or close to the contact angle.

[0035] Furthermore, the blade sharpening device 10 may, after rotating the rotating sharpening tool 11 and the rotating blade 1, bring the cutting edge portion 1a of the rotating blade 1 into contact with the circumferential surface 11a of the rotating sharpening tool 11, or it may rotate the rotating sharpening tool 11 and the rotating blade 1 after bringing the cutting edge portion 1a of the rotating blade 1 into contact with the circumferential surface 11a of the rotating sharpening tool 11. In addition, the blade sharpening device 10 only needs to have a reference vertical plane parallel to the central axis of the rotating blade 1, and is not limited to cases where the rotating sharpening tool 11 rotates vertically and the rotating blade 1 rotates horizontally, or where both the rotating sharpening tool 11 and the rotating blade 1 rotate vertically, or where the rotation occurs within an inclined surface. [Examples]

[0036] An experiment was conducted to polish the cutting edge portion 1a of a rotary blade 1 using a blade polishing apparatus 10 shown in Figures 2 to 4, with a buff as the rotary polishing tool 11. In the experiment, the rotary blade 1 used had a defect 1b, where a part of the cutting edge portion 1a was chipped, as shown in Figure 5(a). In the experiment, the contact angle between the circumferential surface 11a of the rotary polishing tool 11 and the cutting edge portion 1a of the rotary blade 1 was set to 0 degrees, 5 degrees, and 10 degrees, and polishing was performed for 30 seconds. The rotational speed of the rotary polishing tool 11 and the rotary blade 1 during polishing was set to an appropriate constant value. The surface of the cutting edge portion 1a after polishing was measured with a stylus-type surface roughness meter to examine the grinding angle of the cutting edge portion 1a and the state of correction of the defect 1b after polishing. The experimental results are shown in Figure 6.

[0037] Figure 6 shows the results of surface roughness measurement using a surface roughness meter, measuring the surface of the polished cutting edge portion 1a at the location containing the defect 1b, from the center to the periphery of the rotating blade 1. Furthermore, as shown in Figure 5(b), blades where the defect in the rotating blade 1 has been corrected to a state where there is almost no chipping are shown as "OK" in Figure 6. For comparison, the results of surface roughness measurement of the cutting edge portion 1a of the rotating blade 1 before polishing, using a stylus-type surface roughness meter, are also shown in Figure 6.

[0038] As shown in Figure 6, when the contact angle was 0 degrees, it was confirmed that defects remained even after 30 seconds of polishing. In contrast, when the contact angles were 5 degrees and 10 degrees, it was confirmed that the defects were corrected after 30 seconds of polishing. Furthermore, the grinding angles at those times were 5.2 degrees and 10.1 degrees, respectively, and it was confirmed that the cutting edge portion 1a was polished to an angle approximately the same as the contact angle. [Explanation of symbols]

[0039] 1 Rotary blade 1a Cutting edge 1b Defect 10. Blade sharpening device 11 Rotary polishing tools 11a Circumferential surface 12. Polishing tool rotation support section 12a Rotary motor 12b Rotating shaft 13 Rotary blade mounting section 13a Rotary motor 14 Moving mechanism

Claims

1. A blade sharpening device for sharpening the cutting edge portion of a rotating blade, which is tapered from the tip of the peripheral edge toward the central axis, A rotary polishing tool having a disc shape with a predetermined thickness, and provided to polish the cutting edge portion of the rotary blade at least on its circumferential surface, A polishing tool rotation support unit that supports the aforementioned rotating polishing tool and rotates the aforementioned rotating polishing tool about its central axis, The rotating blade is detachable, and when the rotating blade is attached, a vertical surface perpendicular to the central axis of the rotary polishing tool is parallel to the central axis of the rotating blade, and a surface parallel to the vertical surface and including the central axis of the rotating blade is provided so as to cross the circumferential surface of the rotary polishing tool along the circumferential direction, and a rotating blade mounting portion that rotates the attached rotating blade about its central axis, A moving mechanism that moves the rotating blade mounting portion in two dimensions along the vertical plane such that the circumferential surface of the rotating polishing tool contacts the cutting edge portion of the rotating blade attached to the rotating blade mounting portion, A blade sharpening device characterized by having the following features.

2. The blade sharpening apparatus according to claim 1, characterized in that the moving mechanism is capable of moving the rotating blade mounting portion so that, in a cross section along the vertical plane passing through the contact position between the circumferential surface of the rotating sharpening tool and the cutting edge portion, the contact angle is defined as the angle between the tangent to the circumferential surface and the surface of the cutting edge portion at the contact position, and the contact angle becomes a desired angle.

3. The cutting tool sharpening apparatus according to claim 2, characterized in that the contact angle is 3° to 15°.

4. The blade sharpening apparatus according to claim 2, characterized in that the moving mechanism can automatically move the rotating blade mounting portion so that the contact angle becomes a preset angle, based on the radius of the rotating blade and the angle between a plane perpendicular to the central axis of the rotating blade and the surface of the cutting edge portion.

5. The aforementioned polishing tool rotation support unit is configured to rotate the rotating polishing tool vertically. The aforementioned rotating blade mounting section is configured to rotate the rotating blade horizontally. The aforementioned moving mechanism is configured to move the rotating blade mounting portion horizontally and vertically along the vertical plane. The blade sharpening apparatus according to claim 1, characterized by its features.

Images