JPS6210075Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to an improvement of a slitting knife used for slitting magnetic tape, particularly a slitting knife serving as a lower blade.

BACKGROUND ART A slitting knife used for slitting magnetic tape is composed of an upper blade and a lower blade, and the slitting knife 1A forming the lower blade is known, for example, as shown in FIGS. 1 and 2. . That is, the annular stepped portion 3 is cut out near the outer periphery of one side of the slitting knife body 2 made of steel.
, and furthermore, the side wall 3a of this annular step portion 3 is α
The side wall 3a is tapered at an angle of
A cutting edge portion 5 is formed by the intersection of the blade and the outer circumferential surface 4 of the slitting knife main body 2, and a plurality of blades are arranged in a mounting arbor (not shown) for use.

Furthermore, there is a slitting knife made of cemented carbide as shown in FIG. 3. This suritsuta knife 1B
This was previously proposed by the present applicant (see Japanese Utility Model Application Publication No. 51-114783), in which the central part of the side surface of the annular slitting knife body 2 is recessed, and the remaining peripheral edge of the side surface and the outer peripheral surface 4 are The perpendicular portion is the cutting edge portion 5.

Problems to be Solved by the Invention In the former slitting knife 1A, the distance K between the cutting edge portions 5, 5 when a plurality of blades are arranged and used is
In order to keep the blades uniformly aligned with high precision, the distance from the cutting edge 5 to one side of the slitting knife body 2 must be adjusted.
K ₁ and the distance to the other side K ₂ (K
= K ₁ + K ₂ ) must both be maintained at a predetermined accuracy,
There are problems in that the interval adjustment is complicated and the manufacturing cost increases. In addition, since the angle of the cutting edge part 5 is acute, if the slitting knife body is made of cemented carbide, the drawback of cemented carbide, which is "brittleness", will appear in the cutting edge part 5, and the cutting edge part 5 will easily break. There's a problem.

In addition, in the latter suritsuta knife 1B,
Since the angle of the cutting edge portion 5 is a right angle, its strength is high, and therefore, damage to the cutting edge portion 5 can be significantly reduced compared to the former one. However, on the other hand, since the cutting edge portion 5 is at a right angle, there is a problem that the cutting performance is lower than that when the cutting edge portion 5 is at an acute angle. Further, when actually used, a spacer S is required to insert the cutting edge of the upper blade slitting knife body between the adjacent slitting knife bodies 2, which increases the number of parts and manufacturing costs. Moreover, in order to keep the distance K between the cutting edge parts 5, 5 constant and accurate, it is necessary to adjust the thickness K ₃ at the central part of the side surface of the slitting knife body 2 and the step between the central part of the side surface and the peripheral part.
Not only is it necessary to maintain K ₄ to a given accuracy;
The thickness K ₅ of the spacer S must also be finished with high precision, making it complicated to adjust the spacing and increasing manufacturing costs.

Means for Solving the Problem This invention is a magnetic slitting knife that is used by arranging a plurality of annular slitting knives in the axial direction with the annular step portions facing the same direction. In the tape slitting knife, both side surfaces of the slitting knife body are perpendicular to the central axis of the slitting knife and substantially orthogonal to the outer circumferential surface, and the outer circumferential surface of the slitting knife body has a surface roughness of 0.4-S or less. The other side of the slitting knife body located on the opposite side of the stepped part is finished to a surface roughness of 0.2-S or less, and the intersection of these outer peripheral surfaces and the other side is used as the cutting edge. This solves the problem.

Function A plurality of slitting knives are arranged in the axial direction facing the same direction, and the cutting edge of the upper blade is inserted between the annular step and the slitting knife body adjacent thereto. The spacing between the cutting edges is determined by the distance from one side of the slitting knife body to the other side, that is, the thickness of the slitting knife body itself. Other than this thickness, there are no other factors that affect the spacing between the cutting edges. Therefore, the accuracy can be easily made high.

In addition, the intersection of the outer circumferential surface of the suritsuta knife body and the other side surface orthogonal thereto is the cutting edge, and its strength is strengthened, so even if the suritsuta knife body is made of cemented carbide, the cutting edge will break. There's nothing to do. Moreover, the surface roughness of the outer peripheral surface is 0.4
-S or less, and the surface roughness of the other side is finished to 0.2S or less, so the cutting performance of the cutting edge will not deteriorate compared to a conventional slitting knife that has an acute angle at the cutting edge. rare.
That is, the reason why the surface roughness of the outer circumferential surface and the other side surface is set within the above range is based on experimental results, and if they are set outside the above range, minute chipping of 3μ or more will occur. When chipping of 3μ or more occurs, cracks occur in the magnetic layer of the magnetic tape, causing problems such as deterioration of the performance of the magnetic tape. If it is set within the range, chipping of 3 microns or more will not occur at the cutting edge, and therefore it is possible to prevent the performance of the magnetic tape from deteriorating.

The main body of the slitting knife has a simple shape with both sides parallel to each other and the outer peripheral surface perpendicular to these sides, so it is easy to work with and can easily improve surface roughness. You can complete the above.

Embodiment Hereinafter, the content of this invention will be clarified by describing the embodiment shown in FIGS. 4 and 5.

First of all, the features of this device are as follows: (A) Both side surfaces of the slit knife body are perpendicular to the axis of the slit knife body and substantially perpendicular to the outer peripheral surface, and (B) The slit knife body The outer peripheral surface of the sliver knife is finished to a surface roughness of 0.4-S or less, and the other side of the slitting knife body located on the opposite side of the annular step is finished to a surface roughness of 0.2-S or less, and (C) those outer peripheral surfaces and It has a structural feature in that the intersection with the other side surface is the cutting edge.

Among these structural features, the structure (A) provides an advantage in terms of strength by making the slitting knife body made of cemented carbide, and can prevent breakage of the cutting edge. In this case, configuration (A)
If the cutting edge is made at right angles as shown in the figure, the cutting performance will inevitably deteriorate, but configuration (B) prevents the cutting performance from decreasing. Furthermore, from configuration (C), the spacing between the blade edges is determined by the thickness of the slitting knife body, so in order to improve the spacing accuracy between the blade edges, it is only necessary to make the slitting knife body highly accurate. . Therefore, the interval accuracy can be easily and inexpensively increased. Moreover, since both sides of the slitting knife body are orthogonal to the axis, they are parallel to each other, and therefore the slitting knife can be used for plane wrapping processing, thereby easily increasing the thickness accuracy of the slitting knife. can.

Next, regarding each embodiment shown in FIGS. 4 and 5, the slitting knife 10 shown in FIG.
The slitting knife 20 shown in the figure is also made of cemented carbide, and one side 1 of its main body 11, 21 is
Although there is a slight difference in the shape of the notch near the outer periphery of each main body 11, 22, one side 1 of each main body 11, 21
The vicinity of the outer periphery of the blades 2 and 22 is cut out over the entire circumference to form an annular stepped portion 13, 23, which forms an annular shape, and is perpendicular to the central axis of the slitting knife body 11, 21, similar to the one side surface 12, 22 described above. Other aspects 1
4 and 24 are finished to a surface roughness of 0.2-S or less, and the outer peripheral surfaces 15 and 25 parallel to the central axis are
Finished to a surface roughness of 0.4-S or less, the intersection of these surfaces 14, 25; 24, 25 forms the cutting edge 1.
6.26.

In the above-mentioned slitting knives 10, 20, since the outer circumferential surfaces 15, 25 and the side surfaces 14, 24 are substantially orthogonal, the cutting edge angle of each cutting edge portion 16, 26 is approximately 90°, and the cutting edge portion 16, 26 is improved, and its damage can be prevented. Furthermore, if the cutting edge angle of the cutting edge portions 16, 26 is set to approximately 90°, the strength will be improved, but the cutting performance will be reduced. It has been confirmed that if the surface is finished to such a roughness, the cutting performance will hardly deteriorate compared to a conventional slitting knife with an acute angle at the cutting edge, and there will be no problem in cutting magnetic tape. There is. That is, the sides 14, 2
4. If the surface roughness of the outer circumferential surfaces 15, 25 deviates from the above values, minute chipping of 3 μ or more will occur at the cutting edge portions 16, 26. Then, the cutting edge part 1
If chipping of 3 μ or more occurs on 6, 26,
Cracks occur in the magnetic layer of the magnetic tape, causing problems such as degrading the performance of the magnetic tape.
If the surface roughness is within the above range, such a problem will not occur. In addition, suritsuta knife 1
0, 20 are side surfaces 1 forming the cutting edge portions 16, 26
Since 4 and 24 are flat surfaces perpendicular to the central axis, each side surface 14 and 24 can be wrapped by wrapping when manufacturing these slitting knives 10 and 20, resulting in good working efficiency. Further, the distance K between the cutting edge portions 16 and 26 is
Since the thickness T of 0 is itself, in order to make the interval K highly accurate, the thickness T of the slitting knives 10 and 20 is
All you have to do is process it to the desired thickness. Therefore, the interval adjustment work is easy and the manufacturing cost can be reduced. In addition, when re-grinding, the outer peripheral surface 1
If 3 and 23 are reground, the interval T will not change.

Next, we will explain the results of experiments conducted to confirm the above-mentioned effects to further clarify this idea. In this experiment, the amount of chipping of the blade edges 16 and 26 was measured after cutting the magnetic tape, and the cutting conditions were as follows.

Cutting speed...100m/min Speed ratio of lower blade, magnetic tape, and upper blade...1:1:1.0.3 Cutting length...10000m Figure 6 shows the surface roughness of the side surface forming the blade edges 16 and 26 Figure 7 shows the amount of chipping when the surface roughness of the outer circumferential surface is changed with constant (0.2-S).
The surface roughness of the side surface is changed as follows.
As is clear from these figures, when the surface roughness of the outer peripheral surface exceeds 0.4-S, the surface roughness of the side surface becomes 0.2-S.
It can be seen that chipping of 3μ or more occurs at the cutting edge portions 16, 26 in any case where the thickness exceeds 3μ. In particular, when the surface roughness of the outer peripheral surface exceeds 0.4-S, the size of chipping that occurs at the cutting edge portions 16 and 26 not only exceeds 3μ, but also the size of chipping that occurs rapidly increases. do.

Effects of the invention As described above, in this invention, both side surfaces of the slitting knife body are made perpendicular to the central axis of the slitting knife, and substantially orthogonal to the outer circumferential surface, and furthermore, the outer circumferential surface of the slitting knife body is 0.4- The other side of the slitting knife body located on the opposite side of the annular step is finished to a surface roughness of 0.2-S or less, and the intersection of these outer peripheral surfaces and the other side is used as the cutting edge. Because of this, it is possible to easily and inexpensively increase the spacing accuracy of the cutting edge, and to prevent breakage of the cutting edge, and also to prevent the performance of the magnetic tape from decreasing due to the reduction in cutting performance. Effects such as being able to prevent this can be obtained.

[Brief explanation of the drawing]

Figure 1 is a vertical side view of a conventional suritsuta knife.
Fig. 2 is an enlarged cross-sectional view of the main part, Fig. 3 is a vertical cross-sectional view of another conventional slitting knife, Fig. 4 is a longitudinal cross-sectional view of the main part showing one embodiment of the present invention, and Fig. 5 is another embodiment. FIGS. 6 and 7 are longitudinal sectional views of main parts showing examples, and are diagrams showing experimental results of measuring the amount of chipping occurring at the cutting edge. 10,20... Suritsuta knife, 11,21...
... Slitsuta knife body, 12, 22... One side of Slitsuta knife main body, 13, 23... Annular step part,
14, 24...Other side of the suritsuta knife body, 1
5, 25...Outer peripheral surface, 16, 26...Blade tip.

Claims (1)

[Scope of utility model registration request] In a magnetic tape slitting knife in which a plurality of annular slitting knife bodies each having an annular stepped portion formed on the outer periphery of one side are arranged in the axial direction with the annular stepped portions facing in the same direction, both sides of the slitting knife body are Both are perpendicular to the central axis of the slitting knife body, and substantially perpendicular to the outer circumferential surface, and the outer circumferential surface of the slitting knife body is
The other side of the slitting knife body located on the opposite side of the annular step has a surface roughness of 0.4-S or less.
Finished with a surface roughness of 0.2-S or less,
A magnetic tape slitting knife characterized in that the intersection between the outer circumferential surface and the other side surface is a cutting edge.