JP2003127050A - Method and device for grinding cutting edge blade - Google Patents

Abstract

PROBLEM TO BE SOLVED: To grind a cutting edge with high accuracy in a method for grinding a cutting edge of a blade and a device therefor. SOLUTION: A rotary grinding wheel body 10 is supported movably in a rotary shaft direction at a spindle shaft 22 of a rotary spindle unit 21 and the cutting edge of a round blade 131 is ground by pressing the rotary grinding wheel body 10 toward the round blade 131 of a round blade unit 130 while being energized by a ring spring 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for polishing a cutting blade, and more specifically, for polishing a cutting blade for cutting a thin sheet-like object to be cut with a rotating grindstone. A method and apparatus.

[0002]

2. Description of the Related Art There is known a magnetic tape cutting device for cutting a wide magnetic tape raw material into a generally used narrow magnetic tape, and such a cutting device is usually shown in FIG. 13, for example. In addition, a plurality of upper round blades 3 and lower round blades 4 are arranged in the axial direction on the upper round blade shaft 1 and the lower round blade shaft 2, respectively, and these blades are mounted so that their cutting edges are positioned at predetermined intervals, and The upper round blade 3 and the lower round blade 4 which are opposed to each other are arranged so that the portions in the vicinity of the blade edges overlap in the radial direction, and the upper round blade 3 and the lower round blade 4 are interposed via the upper round blade shaft 1 and the lower round blade shaft 2. Wide magnetic tape roll 5 between both round blades 3 and 4 while rotating and
Is transferred in the direction perpendicular to the paper surface of FIG. 13 with the magnetic layer facing upward, and this magnetic tape raw material 5 is cut into a plurality of elongated strips.

The cross-sectional shape of the cutting edge 4a of the lower round blade 4 including the rotation axis of the lower round blade 4 is formed into a substantially right angled corner, but the substantially right angled corner is chamfered. Cage,
This chamfering improves the sharpness of cutting the magnetic tape, and suppresses the generation of unnecessary protrusions and burrs on the cut surface of the magnetic tape.

Further, the chamfering is carried out by moving a grinding stone fixed to a spindle shaft rotated by a motor together with the motor and the spindle and pressing the grinding stone against the cutting edge of the lower round blade. Has been done.

[0005]

By the way, in recent years, in order to increase the recording density of the magnetic tape, PEN is used as a base material to extend the length of the magnetic tape accommodated in a cassette or the like.
Since the thickness of the magnetic tape is reduced by using aramid resin or aramid resin, unnecessary protrusions and burrs are easily generated on the cut surface of the magnetic tape due to the materials. In addition, the width of the recording track is narrowed in order to increase the recording density of the magnetic tape, and in order to accurately record or read the signal on this narrow recording track, it is necessary to drive during recording and reproduction. It is necessary to accurately position the magnetic tape in the width direction, so that the distance between the guides for regulating the tape running position is narrowed and the contact pressure between this guide and the side surface of the magnetic tape becomes high. The burr is scraped by the above guide and is easy to fall off. Then, when unnecessary protrusions or burrs are scraped during the running of the magnetic tape, the scraps pass through the recording head or the reproducing head while adhering to the magnetic surface side of the magnetic tape, and dropout occurs. It causes various problems. Therefore, in the case of a magnetic tape having a high recording density in recent years, there is a demand to further improve the quality of the cut surface so that unnecessary convex portions and burrs are not generated on the cut surface of the magnetic tape.

As a result of various investigations concerning the improvement of the quality of the magnetic tape cut surface in response to the above-mentioned demand, chamfering was performed with high accuracy over the entire circumference of the substantially right angle corner of the cutting edge of the lower round blade, for example, When the thin magnetic tape having the above-mentioned thickness is cut by using a lower round blade whose edge has a chamfer of a predetermined shape with an accuracy of ± 0.5 μm, unnecessary protrusions and burrs on the cut surface of these magnetic tapes are formed. It was found that the generation was suppressed and a higher quality cut surface was obtained.

However, in the above-mentioned conventional chamfering method, since the grindstone for polishing the lower round blade is moved integrally with the motor and the spindle as described above, the weight of the mechanism that is moved together with the grindstone is heavy, and It is difficult to control the quantity with high precision, and especially when grinding a runout (surface runout) of the lower round blade of about several μm in the rotation axis direction during grinding, control to move the grindstone following this surface runout. , And it is difficult to control the side pressure when polishing the lower round blade with a grindstone with high accuracy, and as a result, the area where the grindstone hits the blade edge strongly and weakly, or the area where the grindstone hits the edge, There is a possibility that a blank area may occur. Moreover, there is a possibility that the polishing characteristics of the grindstone may change due to the clogging of the grindstone, the dropping of the abrasive grains, etc., so it is difficult to uniformly and highly accurately chamfer the entire circumference of the lower round blade. There's a problem.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cutting blade polishing method and apparatus capable of polishing a cutting blade into a desired shape with high precision. is there.

[0009]

A first method for polishing a cutting blade according to the present invention is a method for polishing a cutting blade, wherein the cutting blade is polished by a rotating rotary grindstone body. Is movably supported and urged toward the cutting blade while being pressed against the cutting blade to polish the cutting blade.

A second method of polishing a cutting blade according to the present invention is the method of polishing a cutting blade in which a rotating blade grinds the cutting blade, wherein the rotating grindstone is rotated by the cutting blade. It is characterized in that the cutting blade is abraded by pressing while elastically deforming or elastically displacing in the axial direction.

The first cutting blade polishing apparatus of the present invention is a cutting blade polishing apparatus comprising a rotating grindstone body and a rotating means for supporting and rotating the rotating grindstone body. , Urging means movably supported by the rotating means in the rotation axis direction of the rotating means and urging the rotating grindstone body in the rotating axis direction toward the cutting blade. It is what

A second cutting blade polishing apparatus according to the present invention is a cutting blade polishing apparatus comprising a rotating grindstone body and a rotating means for rotating the rotating grindstone body.
It has a ring-shaped grindstone portion which can be elastically deformed or elastically displaced in the rotation axis direction of the rotating means when rotating.

The term "movable in the direction of the rotation axis" means that it is movable in the direction including the component in the direction of the rotation axis.

Further, elastically deforming in the rotational axis direction means elastically deforming in a direction including the axial component of rotation. Further, the elastic deformation means a deformation in which a force is generated to return the deformation at least when it is deformed during rotation of the rotary grindstone body, and is configured by combining a plurality of parts. This elastic deformation also includes deformation in the case where a force is generated to restore this deformation when the deformed object is deformed.

Further, elastically displacing in the rotational axis direction means elastically displacing in a direction including an axial component of rotation. The elastic displacement is based on this displacement when the whetstone portion is displaced at least during rotation of the rotary grindstone body in a configuration in which the portion supporting the whetstone portion can be deformed without deforming the whetstone portion itself. It means the displacement that causes the force to return to. The portion supporting the grindstone portion does not necessarily have to be elastically deformable, and may be deformable.

[0016]

According to the first method and apparatus for grinding a cutting blade of the present invention, a rotary grindstone is movably supported in the direction of the rotation axis and pressed against the cutting blade while being urged toward the cutting blade. Since the polishing grindstone is urged and pressed against the cutting blade by urging the rotary grindstone body having a small mass, the relative position error between the grinding device in which the rotary grindstone body is arranged and the cutting blade, such as positioning error or Even if surface wobbling error (surface wobbling amount) occurs, the rotating grindstone itself, which has a small mass, follows the cutting blade by the urging force and is pressed against this cutting blade with a constant side pressure, and under more constant polishing conditions. Since the cutting blade can be polished, the cutting blade can be polished into a desired shape with high precision.

According to the first method and apparatus for polishing a cutting blade of the present invention, the rotating grindstone body is pressed against the cutting blade while being elastically deformed in the axial direction of rotation so as to be ground, so that the rotating grindstone body has a small mass. Since the reaction force of elastic deformation and the component of the centrifugal force when the rotating grindstone is rotated in the direction of the rotation axis presses the rotating grindstone against the cutting blade, a polishing device in which the rotating grindstone is arranged is used. Even if a positional error relative to the cutting blade, such as a positioning error or a surface wobbling error (amount of surface wobbling) occurs, the elastically deformed or elastically displaced portion of the rotary grindstone follows the cutting blade due to the restoring force. Since it is pressed against the cutting blade with a constant side pressure and the cutting blade can be polished under more constant polishing conditions, the cutting blade can be highly accurately polished into a desired shape.

In the first and second cutting blade polishing methods and apparatuses, a large number of blades are arranged adjacent to each other like a cutting blade incorporated in a lower round blade unit of a magnetic tape cutting apparatus. When polishing the cutting blade,
Positioning errors are accumulated as the polishing device is sequentially positioned with respect to each cutting blade, and the positioning error of the polishing device with respect to this cutting blade may increase as the cutting blade is polished later. Since the rotating grindstone body itself including the positioning error or the elastically deformed or elastically displaced portion in the rotary grindstone body follows the surface to be ground of the cutting blade, each cutting blade is desired as in the above. The shape can be polished with high precision, and a remarkable effect due to the application of the present invention can be expected.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a cutting blade polishing apparatus of the present invention applied to a round blade unit polishing apparatus for polishing a cutting blade of a lower round blade unit of a magnetic tape cutting apparatus described above.
2 is a side view of the round blade unit polishing apparatus, FIG. 3 is an enlarged front view of a part of the round blade unit polishing apparatus, and FIG. 4 is a circle. FIG. 5 is an enlarged view showing how the rotary grindstone is moved when the blade is polished, FIG. 5 is a diagram showing details of C value and H value, and FIGS. 6 to 9 are experiments using the round blade unit polishing device. It is a figure explaining the result of.

The round blade unit polishing apparatus according to the first embodiment of the present invention comprises a polishing apparatus main body 100 and a polishing apparatus transfer means for transferring and positioning the polishing apparatus main body 100 in the up and down direction indicated by the arrow X in the figure. 110 and a circular blade unit 130 formed by arranging a number of thin blades, which are thin-cutting blades, in the rotation axis direction are chucked and rotated, and the circular blade unit 130 is transferred in the horizontal direction Y direction in the drawing and positioned. And a round blade rotation transfer means 120.

The polishing device transfer means 110 and the round blade rotation transfer means 120 are arranged on a common base 140.
As shown in FIG. 2, the polishing device transfer means 110 is connected to the transfer support 81 that supports the polishing device main body 100, and is connected to the transfer support 81 in the vertical direction of the arrow X in the drawing. The polishing apparatus main body 100 is provided with a linear guide for transfer and an up-and-down transfer mechanism 80 using a ball screw or the like, and is driven by the up-and-down transfer mechanism 80 via a transfer support 81.
Are transferred in the direction of the arrow X.

The round blade rotation transfer means 120 is the chucking base 1 which is transferred in the Y direction shown in FIG.
27 and a first member disposed on the chucking base 127.
Stanchions 125 and second stanchions 126 and first stanchions 1
Center shaft 1 for chucking the round blade unit 130, which is arranged on the second support column 126 and the second support column 126, respectively.
21 and a rotary drive shaft 122, a rotary drive unit 124 for rotating the rotary drive shaft 122, a mechanism that uses a linear guide, a hydraulic cylinder, and the like to move the chucking base 127 in the arrow Y direction.
And 23. This round blade rotation transfer means 120 is
By driving the left-right transfer mechanism 123, the center shaft 1
21 and the rotary drive shaft 122, the round blade unit 130 chucked between the chuck 21 and the rotary drive shaft 122 is transferred in the direction of the arrow Y through the chucking base 127, and the rotary drive unit 124 is provided.
The circular blade unit 130 is rotated via the rotary drive shaft 122 by the driving.

The polishing apparatus main body 100 comprises a rotary grindstone body 10
And a whetstone rotating means 20 which is a rotating means for supporting and rotating the whetstone body 10, a urging means 30 for urging the whetstone body 10 in the rotational axis direction, and a connecting arm 40.

The grindstone rotating means 20 is a rotary spindle unit 21 for transmitting a rotational force for rotating the rotary grindstone body 10.
And the spindle shaft 2 of this rotary spindle unit 21
2 through a spindle holder 24 that fits so as to rotate integrally with the spindle shaft and that supports the rotary grindstone body 10, and a belt 25 that hangs the spindle shaft 22 on a pulley fixed to the spindle shaft 22. The rotary spindle unit 21 and the polishing motor 26 are connected to and integrated with the connection arm 40. The spindle holder 24 fitted to the spindle shaft 22 is fixed to the spindle shaft 22 with screws 23 (see FIG. 3).

The connecting arm 40 is the grinding wheel rotating means 20.
1 and supports the grindstone rotating means 20 on the XY plane in FIG.
Is connected to the transfer support 81 so as to be adjustable in angle.

As shown in FIG. 3, the rotary grindstone body 10 has a disc-shaped grindstone base plate 11 having a high rigidity and an opening that fits into the fitting portion 27 of the spindle holder 24, and a side surface of the grindstone base plate 11. And a grindstone tip portion 12 formed on the outer periphery of the. The rotary grindstone body 10 has the spindle holder 2 so that the grindstone tip portion 12 side faces a flange portion 28 described later.
4 is fitted in the fitting portion 27 and is supported so as to be movable in the rotation axis direction of the spindle shaft 22. In this rotary grindstone body 10, a rotation stop pin 13 fixed in a flange pin hole 29 formed in a flange portion 28 at the tip of the spindle holder 24 is inserted into the grindstone pin hole 14 of the grindstone base plate 11.
The rotational force of the spindle shaft 22 is transmitted to the rotary grindstone body 10 via the rotation stop pin 13. The flange pin hole and the detent pin fixed to the hole are arranged at two positions at rotational axis targets so as not to disturb the balance during rotation, and the grindstone pin hole of the grindstone base plate 11 is also described above. It is arranged according to the position of the rotation stop pin. With the above structure, the rotating grindstone body 10 is movable in the rotation axis direction of the grindstone rotating means 20.
Supported by 2.

The urging means 30 has a spring receiving disk 33 having a taper surface T which comes into contact with a screw portion 31 screwed into the screw portion 42 of the spindle holder 24 and a ring spring 32 which will be described later.
And a ring spring 32 formed by rolling a coil spring into a ring shape and having an expandable and contractable ring diameter. With the ring spring 32 being arranged between the tapered surface T of the spring receiving disk 33 and the rotary grindstone body 10, the spring receiving disk 3 is provided.
The screw portion 31 of No. 3 is screwed to the screw portion 42 of the spindle holder 24 so that the spindle holder 24 and the spring receiving disk 33 are integrated.

The ring spring 32 moves along the tapered surface T while reducing its diameter by its own contracting force to move the rotary grindstone 10 toward the flange portion 28 (right side in FIG. 3,
Bias in the direction of arrow V). As a result, the urging means 30 causes the rotary grindstone body 10 to move in the direction of the rotation axis into the round blade unit 130.
Bias towards the round blade of.

Next, the operation of the above embodiment will be described.

The round blade unit 130 is sandwiched between the center shaft 121 arranged on the first support 125 of the round blade rotation transfer means 120 and the rotary drive shaft 122 arranged on the second support 126. After chucking, the round blade unit 130 is moved in the direction of the arrow Y in the figure by the left and right transfer mechanism 123, and the first round blade 131 is positioned at the initial setting position where it is polished. The round blade unit 130 positioned at the initial setting position is rotated by the rotary drive force transmitted from the rotary drive unit 124 via the rotary drive shaft 122.

The polishing apparatus main body 100 includes a spindle shaft 22.
Of the connecting arm 40 to the vertical transfer base 81 of the polishing apparatus transfer means 110 so that the rotation axis L1 of the polishing blade tilts with respect to the rotation axis L2 of the round blade unit 130 by a predetermined angle α.
After being fixed via the, the vertical transfer mechanism 80 moves the round blade unit 130 downward so as to approach the round blade unit 130 and stops at a predetermined position (height). At this time, the polishing apparatus body 100 is stopped so that the grindstone tip portion 12 is positioned between the two round blades (between the first round blade 131 and the second round blade 132) as shown in FIG. It

Next, the rotating grindstone body 10 is rotated through the spindle shaft 22 by driving the polishing motor 26, and the grindstone tip portion 12 and the cutting edge of the first round blade 131 are observed while observing them with a tool microscope (not shown). The circular blade unit 130 is controlled by the blade rotation transfer means 120 (left and right transfer mechanism 123).
The position of the grindstone tip 12 and the first round blade 131
The round blade unit 130 is positioned at the first polishing start position with a predetermined distance from the blade edge Q1. When the first round blade 131 is positioned at the first polishing start position, the first rotation of the round blade rotation transfer means 120 causes the first round blade unit 130 to move to the first position.
The circular blade 131 of is fed to the left side of the drawing (direction of arrow W) in the direction of approaching the rotary grindstone body 10 by a predetermined distance,
The cutting edge Q1 of the round blade 131 and the whetstone tip portion 12 come into contact with each other, and the cutting edge of the first round blade 131 is ground by the rotary whetstone 10.

When the polishing of the first round blade 131 is completed, the polishing apparatus main body 100 is moved upward by the polishing apparatus transfer means 110 along the X direction, and then the round blade unit 130 is moved by the round blade rotation transfer means 120. When the polishing apparatus main body 100 is conveyed in the direction of arrow V in the drawing by a distance corresponding to the thickness of one round blade, the polishing apparatus main body 100 is again moved downward by the polishing apparatus transfer means 110 and stopped at a predetermined position (height). . As a result, the whetstone tip portion 12 is positioned between the second round blade 132 and the third round blade 133, and this position is the second polishing start position for polishing the blade edge of the second round blade 132. Become.

Next, the second round blade 131 of the round blade unit 130 is moved by the round blade rotation transfer means 120 so that the grindstone tip portion 1 is moved.
2 is sent by a predetermined distance in the direction approaching 2 (the direction of arrow W in the figure), the cutting edge Q2 of the second round blade 132 of the round blade unit 130 and the grindstone tip portion 12 come into contact with each other, and the second round The cutting edge of the blade 132 is polished.

By repeating the above operation, all the blade edges of the round blades of the round blade unit 130 are polished, and the polishing of the round blade unit 130 by the round blade unit polishing device is completed.
Note that this operation is repeated by automatic cycle control.

Here, the details of the grinding of the edge of the round blade by the rotary grindstone body 10 will be described.

When the polishing apparatus body 100 is positioned at the first polishing start position, the predetermined interval between the grindstone tip portion 12 and the cutting edge Q1 of the first round blade 131 is 0.2 mm. When the round blade 131 is moved by 0.4 mm which is a predetermined distance from the polishing start position of No. 1 in the direction approaching the grindstone tip portion 12 (direction of arrow W in the drawing), the grindstone tip portion 12 moves to the first round blade 131. After touching the cutting edge,
Predetermined distance (predetermined amount of polishing) by the circular blade 131 of
The initial position J of the rotary grindstone body 10 shown in FIG.
The rotary grindstone body 10 located at (shown by the two-dot chain line) is about 0.2 mm (0.
4 mm-0.2 mm) and moved to position J '. At this time, the diameter of the ring spring 32 increases as the ring spring 32 moves along the tapered surface T of the spring receiving disk 33 toward the spring receiving disk 33 side (the direction of the arrow W in the drawing), whereby the rotary grindstone body 10 described above. Absorbs the amount of movement corresponding to the amount of polishing. Then, polishing is performed in a state where the rotary grindstone body 10 receives a biasing force in the arrow V direction by the contracting force of the ring spring 32. Since the grinding is performed in such a state, even if the first round blade 131 is shaken in the rotation axis direction, the grindstone tip portion 12 having a small mass is urged by the ring spring 32 to urge the blade tip of the first round blade 131. Follows the runout of the blade with a substantially constant side pressure without leaving the cutting edge.
The round blade 131 can be polished. Further, after the first round blade 131 comes into contact with the grindstone tip portion 12, it further moves in the direction of the arrow W in the drawing to move the grindstone tip portion 12 (the rotary grindstone 1
0) even if there is an error in the amount of polishing that is the distance to move the ring spring 32, there is little fluctuation in the force (that is, the side pressure) by which the ring spring 32 urges the rotating grindstone body 10. Can be polished, and the polishing amount can be accurately controlled by controlling the polishing time.

That is, the above-mentioned polished first round blade 13
As shown in FIG. 5, a cross-sectional shape obtained by cutting with a plane passing through the rotation axis of the round blade unit 130 of the first blade tip Q1 has a side E corresponding to the outer peripheral surface of the round blade parallel to the rotation axis L2 of the round blade unit 130. C value (the chamfer length in the tape surface direction), which is the chamfer length, and H value (the chamfer direction in the cutting direction), which is the chamfer length at the side F corresponding to the side surface of the round blade substantially orthogonal to the rotation axis. When expressed as length, this C value and H value (however, C value <H
Value) and the angle of inclination θ represented by
Rotation axis L of the spindle shaft 22 with respect to rotation axis L2 of
The tilt angle α is approximately equal to 1, and the C value can be controlled with an accuracy of ± 0.5 μm by controlling the polishing time.

Since the rotary grindstone 10 is movably fitted in the fitting portion 27 of the spindle holder 24 and there is a clearance between the rotary grindstone 10 and the fitting portion 27, after the round blade comes into contact with the rotary grindstone body 10, Further, when the rotary grindstone body 10 is tilted by moving in the direction of the arrow W in the figure (depending on the amount of polishing), the angle of the side surface of the rotary grindstone body 10 with respect to the rotation axis L2 of the round blade unit 130 changes. Since the contact angle of the grindstone tip portion 12 formed on the side surface of the rotary grindstone body 10 with the round blade changes in accordance with the above, the inclination of the blade edge of the round blade represented by the C value and the H value is changed. Angle does not completely match the inclination angle α of the rotation axis L2 of the spindle shaft 22 and a slight error occurs, but the amount of polishing deviation is large.
Since it is smaller than the diameter of 0, the above error can be ignored.

Hereinafter, the rotation speed of the round blade unit: 300 rp
m, number of rotations of the rotating whetstone: 350 rpm, type of whetstone:
The experimental results under the polishing conditions of Nagoya Diamond SD7000 will be described.

1. Regarding polishing unevenness, as shown in FIG. 6, the blade tip of the same round blade at the first measurement point A, the second measurement point B, and the third measurement point C where the round blade is divided into three in the circumferential direction. When the C value of
As shown in FIG. 7, the variation in the value is the amount of polishing deviation (polishing deviation: 0.05 mm, 0.10 mm, 0.1 mm).
5 mm, 0.20 mm, about ± 0.1 μm, and the grindstone part follows the deflection of the blade edge of the round blade in the direction of the rotation axis to perform polishing at a constant side pressure (polishing condition). It can be seen that the polishing unevenness hardly occurs. In addition,
At this time, the swing width of the blade edge of the round blade in the direction of the rotation axis is approximately ± 5μ.
m.

2. Relationship between polishing amount and C value As for the relationship between the polishing amount and C value, as in the above, as shown in FIG. 7, even if the polishing amount changes from 0.05 mm to 0.2 mm, the C value is The amount of increase is 0.5 μm or less with a slight increase in accordance with the amount of deviation, and the conveyance error (tens of μm) of the round blade unit due to the conveyance mechanism of the round blade rotation positioning means and the blade edge of the round blade. Since it is easy to suppress the total sum with the touch error (several μm) to about 0.05 mm (50 μm), if the target value of C value is set to 4 μm, the C value is adjusted to 4 μm ± 0. It can be seen that it is easy to carry out the processing for finishing the dimension within 5 μm.

3. Regarding the relationship between the C value and the polishing time, as shown in FIG. 8, the C value also increases as the polishing time increases. For example, in the vicinity of the polishing time of 60 seconds where the C value is about 4 μm, the C per 10 seconds is increased. The change in value is about 0.3 μm to 0.5 μm, and the C value is, for example, 4 μm ± 0.5 μm.
It turns out that it is easy to process with an accuracy of about m.

However, in the case where the processing is performed so that the C value is 1 μm or less, the polishing amount per unit time is too large under the above polishing conditions (polishing is required to polish the C value to 1 μm or less). Since the time is controlled with an accuracy of 1 second or less), it is necessary to change the polishing conditions. For example, make the grain size of the grindstone finer,
It is necessary to change the polishing conditions such as using a ring spring with a weaker stretching force to reduce the side pressure. By changing the polishing conditions as described above, it is possible to select processing conditions that allow polishing so that the C value is about 0.5 μm.

4. Regarding variation in C value of each round blade when polishing the round blade unit, as shown in FIG. 9, processing from the 15th round blade to the 25th round blade of the round blade unit with a target C value of 4 μm Then
C from the 28th round blade to the 38th round blade of the round blade unit
As a result of processing with a target value of 6 μm, the range of variation in C value from the 15th round blade to the 25th round blade is 3.9.
The range of variation of C value from the 28th round blade to the 38th round blade of the round blade unit is 5.8µm.
To 6.4 μm, and the C value is ± 0.5 with respect to the target value.
It can be seen that processing can be performed with an accuracy of μm.

As a result of the above experiment, even if 30 or more round blades were continuously polished, the clogging of the grindstone was small,
It can be seen that the effect of extending the life of the cutting edge can be expected by polishing the cutting edge into a shape capable of obtaining high cutting quality.

Further, in the above embodiment, the ring spring is used as the biasing means, but instead of the ring spring, various elastic biasing means such as a disc spring or a rubber O-ring or a biasing means having an action equivalent thereto. Can be used.

Further, in the above-mentioned embodiment, the example of the embodiment in which the urging means and the grindstone rotating means (spring receiving disk) are integrated is shown, but the urging means 10 and the grind rotating means 20 are combined. Alternatively, for example, the rotating whetstone body rotated by the whetstone rotating means may be biased without rotating the biasing means.

FIG. 10 is a diagram showing a schematic structure of a polishing apparatus main body portion which is a main part of the polishing apparatus according to the second embodiment of the present invention. The polishing apparatus of the second embodiment has the first
In the second embodiment, the configuration of the spindle holder, the rotating grindstone body, and the urging means arranged on the spindle shaft is changed, and the other configurations are the same as those of the first embodiment. The application of the present polishing apparatus to the round blade unit polishing apparatus for polishing the cutting blade of the lower round blade unit of the magnetic tape cutting apparatus described above is also the same as in the first embodiment.

The polishing apparatus main body of the second embodiment comprises a rotating grindstone body 80 and a rotating means 50 for rotating the rotating grindstone body 80, and the rotating grindstone body 80 is arranged in the rotation axis direction of the rotating means 50. It has a ring-shaped grindstone portion 83 that is elastically displaceable.

The rotating means 50 has a rotary spindle unit 21 for transmitting a rotational force for rotating the rotary grindstone body 10 and a polishing motor. The polishing motor uses the spindle shaft 22 of the rotary spindle unit 20 as the spindle shaft 22. It is rotated through a belt that is hung on a pulley fixed to 22.

The rotary grindstone body 80 has a boss portion 81 fitted to the spindle shaft 22, a disc body 82 fixed to the boss portion 81, and a grindstone layer laminated on the outer peripheral portion of the side face of the disc body 82. And a ring-shaped grindstone portion 83 formed by.
The disk body 82 is a thin steel plate material (about 0.2 mm).
And has elasticity in the rotation axis direction and is displaceable in the rotation axis direction.

The boss portion 81 of the rotary grindstone body 80 is fitted to the spindle shaft 22 by a mechanism using a key groove and a key.
It is fixed by screws 23 and is rotated by driving the spindle shaft 22.

This polishing apparatus main body is mounted on the above-mentioned round blade unit polishing apparatus, and by setting the rotation axis L1 of the spindle shaft 22 at an angle α with respect to the rotation axis L2 of the round blade unit, the first embodiment described above is performed. The round blade of the round blade unit can be polished similarly to the form.

Here, an elastically displaceable ring-shaped grindstone portion 8 is provided.
The polishing of the blade edge of the round blade by 3 will be described.

When polishing a round blade with this polishing apparatus, the grindstone portion 83 forms a flat surface due to the centrifugal force when the rotary grindstone body 80 is rotated, but the round blade of the round blade unit 130 is moved to the grindstone portion 83. When they are brought into contact with each other and the round blade unit 130 is conveyed by a predetermined polishing amount in the direction toward the grindstone portion 83, the grindstone portion 83 causes the first round blade 13 to move as shown in FIG.
The vicinity S of the region in contact with 1 is elastically deformed. The reaction force of this elastic deformation becomes an urging force, and the centrifugal force generated in the grindstone portion 83 by the rotation of the rotary grindstone body 80 acts as a urging force to direct the grindstone portion 83 toward the round blade. Polishing is performed in a state of being urged by the pressure. At this time, the fluctuation of the urging force with respect to the change of the polishing displacement is small, and the grindstone portion 83 follows the round blade even if the blade edge of the round blade is swung or there is an error in the polishing displacement, so that the polishing condition is always constant. This round blade can be polished, and the polishing amount of the blade edge can be accurately controlled.

As shown in FIG. 12, a disk portion 86 made of a steel thin plate material (having a thickness of about 0.2 mm) is fixed around the boss portion 85 fitted to the spindle shaft 22, and further By forming the grindstone portion 87 having high rigidity around the disc portion 86, the grindstone is elastically deformed without deforming the grindstone portion 87, which is a part of the rotary grindstone body other than the grindstone portion 87. The same effect as described above can be obtained by using a rotating grindstone body configured to displace the portion 85, that is, to elastically displace the grindstone portion 87.

A thin plate material made of steel does not necessarily have to be used for the disk portion supporting the grindstone portion, and any material that can be elastically deformed may be used. Further, it is also possible to use a deformable material, such as a fibrous material, which is not elastically deformed, for the disc portion supporting the grindstone portion. If such a material is used for the disc portion, at least when the grindstone portion is displaced during rotation of the rotary grindstone body, a restoring force for restoring this displacement can be generated.

The above-mentioned polishing method can utilize the equipment and parts used for general grinding or polishing, and the manufacturing costs of the rotary grindstone and the polishing apparatus can be kept low.

Further, the above polishing method has many factors controlling the polishing amount (for example, side pressure, grinding stone mesh, polishing time,
The rotational speed of the grindstone and the rotational speed of the object to be polished can be selected, and the C value of the cutting edge can be accurately controlled to any value by setting appropriate polishing conditions.

Further, in the above embodiment, the object to be polished is the thin cutting blade, but the present invention is not limited to the thin cutting blade, and may be applied to the polishing of a round blade or a flat blade for cutting a thick material. Is possible. Further, as the object to be cut by the cutting blade, in addition to the magnetic tape original material, for example, a photosensitive material such as a photographic film or a photographic printing paper mainly made of a non-metal material,
Examples thereof include a metal foil made of a metal material, and a metal thin plate used as an exterior of a battery and a cartridge.

Further, in the above embodiment, when polishing each round blade of the round blade unit, the round blade unit was moved with respect to the polishing apparatus main body. However, the polishing apparatus main body is moved to polish each round blade. May be performed.

Further, as the rotation speed of the rotary grindstone is slowed down, the R shape of the apex angle portion of the substantially right angled corner of the cutting edge can be increased, so that the minute speed can be adjusted by adjusting the rotation speed. It is also possible to control the R shape of the apex angle portion.

[Brief description of drawings]

FIG. 1 is a front view showing a schematic configuration of a round blade unit polishing apparatus according to an embodiment of the present invention.

FIG. 2 is a side view of a round blade unit polishing device.

FIG. 3 is an enlarged view showing how a round blade is polished.

FIG. 4 is an enlarged view showing a state in which a rotating grindstone body moves when a round blade is polished.

FIG. 5 is a diagram showing details of C value and H value.

[FIG. 6] Measurement points A, B, which are obtained by equally dividing a circular blade into three in the circumferential direction.
Diagram showing C

FIG. 7 is a diagram showing a relationship between the C value and the variation in the C value of the cutting edge of the same circular blade and the C value.

FIG. 8 is a diagram showing a relationship between C value and polishing time.

FIG. 9 is a diagram showing variations in the C value of each round blade when the round blade unit is polished.

FIG. 10 is a diagram showing a configuration of a rotary grindstone body having a ring-shaped grindstone portion that is elastically deformable in a rotation axis direction.

FIG. 11 is a diagram showing a state in which the whetstone portion contacts the round blade during polishing and the vicinity of the contact region is elastically deformed.

FIG. 12 is a view showing a rotary grindstone body having a grindstone portion capable of elastic displacement.

FIG. 13 is a diagram showing a schematic configuration of a magnetic tape cutting device.

[Explanation of symbols]

10 rotating whetstone 11 Wheel base plate 12 Whetstone part 20 Wheel rotation means 22 Spindle shaft 30 biasing means 100 polishing equipment 130 Round blade unit

Claims (4)

[Claims] 1. A method for polishing a cutting blade, which polishes a cutting blade with a rotating rotary grindstone body, wherein the rotary grindstone body is movably supported in a rotation axis direction of the rotary grindstone body and is directed toward the cutting blade. A method for polishing a cutting blade, comprising pressing the cutting blade while urging it to polish the cutting blade. 2. A method for polishing a cutting blade, which polishes a cutting blade with a rotating rotary grindstone body, wherein the rotating grindstone body is pushed by the cutting blade while elastically deforming or elastically displacing in the rotational axis direction of the rotary grindstone body. A method of polishing a cutting blade, which comprises abutting and polishing the cutting blade. 3. A cutting blade polishing apparatus comprising a rotating grindstone and a rotating means for supporting and rotating the rotating grindstone, wherein the rotating grindstone is movable in a rotation axis direction of the rotating means. A cutting blade polishing apparatus comprising: a biasing means that is supported by the rotating means and that biases the rotary grindstone body toward the cutting blade in the rotation axis direction. 4. A cutting blade polishing apparatus comprising a rotating grindstone and a rotating means for rotating the rotating grindstone, wherein the rotating grindstone is elastically deformed in a rotation axis direction of the rotating means during rotation. A cutting blade polishing apparatus having an elastically displaceable ring-shaped grindstone portion.