JPH05253359A - Cutting edge for electric shaver - Google Patents

Abstract

PURPOSE:To provide the above cutting edge with which a beard is finely shaved and of which the sharpness is made excellent. CONSTITUTION:The subject cutting edge is formed of both an Fe-Cr-Ni-Al ferrite alloy comprising Cr of 25 to 35wt.%, Ni of 15 to 25wt.%, Al of 4 to 8wt.%, Ti of 0.0 to 0.5wt.%, at least one of Zr, Y, Hf, Ce, La, Nd, Gd of 0.05 to 1.0wt.% and the rest is Fe, and an oxide film 22 deposited on the surface thereof. When grinding is done in order to form edges, burrs are not produced since the oxide film 22 on the surface has high hardness, and an edge angle of beta can hold strength necessary for the cutting edges and is within a range of 50 deg. to 85 deg., in which cutting resistance is small, and hence a beard can be finely shaved.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electric razor blade, and more particularly to an inner blade.

[0002]

2. Description of the Related Art An electric razor is equipped with an outer blade having a large number of beard-introducing blade holes and an inner blade slidably contacting the inner surface of the outer blade. , Which cuts between the edge of the blade hole of the outer blade and the edge of the inner blade, and FIG. 16 shows an example of the outer blade 1 and the inner blade 2 in a reciprocating electric shaver in cross section. Here, the outer blade 1 has a large number of blade holes 10 formed by grinding a stainless steel plate after sinking.
And then the blade hole 10 is formed by electrolytic polishing or the like.
Is formed by removing the burrs generated at the time of grinding on the hole edge (blade edge) or by an electroforming method of Ni or a Ni alloy to provide a sharp cutting edge angle α. ing.

On the other hand, the inner blade 2 is generally formed of stainless steel and is machined by grinding so that both edges of the upper end serve as the cutting edges. The hardness of the stainless steel is Hv500.
Since it is about 700, the burrs 20 are inevitably formed on the cutting edge portion during the grinding. This frog 20
Is to be removed by performing a burring process such as electrolytic polishing in the same manner as in the case of the outer blade 1, but in the case of a reciprocating electric shaver, a large number of inner blades 2 are used, Since it is difficult to perform such a burring process, the burrs 20 are actually used with the burrs 20.

[0004]

Therefore, when the beard 9 growing on the skin 8 is cut by the outer blade 1 and the inner blade 2, the inner blade 2
In addition to the burrs 20 on the blade edge of No. 2 and the large blade edge angle β (88 to 90 °) as shown in the figure, the cutting edge of the inner blade 2 bites into the whiskers 9 as shown in FIG. 17 (a). The amount of the beard 9 is small, and most of the cutting of the beard 9 is performed by the cutting edge of the outer blade 1 biting into the beard 9. That is, the cut mustache 9
As shown in FIG. 17 (b), the cut surface 91 of the outer blade 2 is the majority, the cut surface 92 of the inner blade 2 is small, and the cut surfaces 91 and 92 of A crimped portion 90 due to the burrs 20 of the inner blade 2 is formed at the boundary.

In this way, the beard 9 is produced by the cooperation of the outer blade 1 and the inner blade 2.
The cutting surface 92 by the inner blade 2 while cutting the
The cut surface is much smaller than the cut surface 91 by the outer blade 1 and has a crimped portion 90, which means that the cut surface is clean. As shown by the chain line in FIG. 16, the inner blade 2 is crushed from both sides with a press to form a V-shaped groove along the blade edge, that is, a so-called beating portion 23 is provided. Since the cutting edge angle β becomes smaller, the number of cutting surfaces 92 due to the cutting of the inner blade 2 is larger than that in the above case. However, since the search is performed after forming the beating portion 23, the grinding burr 20 at the cutting edge is formed.
Is still present. Therefore, the resistance when the cutting edge bites into the whiskers 9 is large and the amount of cut is slightly increased. Further, the curled portion 90 is generated and cannot be escaped. Further, if the cutting edge angle β is made too small, the plate thickness at the squeezed portion 23, which is a constricted portion, decreases, and in the worst case, the inner blade 2 is damaged.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electric razor blade having good sharpness for beard cutting.

[0007]

DISCLOSURE OF THE INVENTION The present invention, however, is not limited to C
r: 25 to 35% by weight, Ni: 15 to 25% by weight, A
1: 4 to 8% by weight, Ti: 0 to 0.5% by weight, Zr,
At least one element of Y, Hf, Ce, La, Nd, and Gd: 0.05 to 1.0 wt%, the balance being Fe-Cr-Ni-Al ferrite alloy with Fe, and being oxidized on the surface It is characterized in that it is formed as a deposit of a material film and has a cutting edge angle of 50 to 85 °.

[0008]

According to the present invention, since the oxide film deposited on the surface of the blade has a high hardness, no burrs are formed on the cutting edge when grinding is performed to form the cutting edge, and the cutting edge angle is In addition to the strength required for the blade being maintained and the cutting resistance being within a small range, the beard can be cut cleanly.

[0009]

The present invention will be described in detail below with reference to the illustrated embodiments.
Then, Fig. 1 shows the outer blade 1 and the inner blade applied to the reciprocating electric razor.
The blade 2 is shown, and the outer blade 1 is the same as in the case of the above conventional example.
Is formed in. And as the inner blade 2, Cr: 25
~ 35 wt%, Ni: 15-25 wt%, Al: 4-8
% By weight, Ti: 0 to 0.5% by weight, Zr, Y, Hf, C
at least one element of e, La, Nd, and Gd:
Fe-C with 0.05 to 1.0 wt% and the balance Fe
Formed in the inner edge shape of r-Ni-Al ferrite alloy
The plate-shaped material provided with
30 minutes or more in high temperature oxidative atmosphere of 0-1300 ℃
By heating, Al on the surface of the base material 21 ₂O₃As the main component
An oxide film 22 having a thickness of 5 μm or more was deposited and formed.
I am using one. This oxide film 22 is fine in the alloy.
Fine and evenly dispersed NiAl (nickel / aluminum)
(Nu intermetallic compound) causes the coarsening of crystal grains.
The hardness of the base material 21 is about Hv500.
However, the hardness of the oxide film 22 located on the surface is Hv2.
It becomes 500-3000.

Then, after forming the oxide film 22 on the surface of the inner blade 2 as described above, a large number of inner blades 2 are embedded in the inner blade base by simultaneous molding, and then the edge which comes into contact with the outer blade 1 It is assumed that the oxide film 22 is exposed at the blade edge by grinding. A part 24 surrounded by a broken line in FIG. 3B shows a part removed by this grinding process. In the inner blade 2 formed in this way, since the constituent member of the blade edge is the oxide film 22 of ultra-high hardness, even if the blade edge angle β is small, the blade may be blunted during the grinding. Instead, it has a sharp cutting edge.

FIG. 2A shows a state in which the beard 9 is cut by the inner blade 2 and the outer blade 1. The outer blade 1 and the inner blade 2 cut the beard 9 from both sides substantially evenly. Beard 9 to go out
As shown in Fig. 2 (b), the cut surface of the outer cutter 1 and the cut surface 92 of the inner cutter 2 have almost the same area, or at least the cut surface 92 of the inner cutter 2 is the entire cut surface. Of 3
It is not less than 50%, and there is no crease at the boundary between the cut surfaces 91 and 92. Therefore, the cutting resistance is small and a good sharpness is exhibited.

Here, the cutting edge angle β of the inner blade 2 is set to 50 to 85 ° by providing the catching portion 23. This is for the following reason. That is, if the angle is 85 ° or more, even if there is no burrs, there is less bite into the beard 9 and most of the cutting of the beard 9 depends on the outer blade 1, and the cutting edge of the outer blade 1 has good sharpness. Since the cutting resistance is not greatly reduced and the cutting resistance does not decrease, it becomes impossible to sufficiently improve the sharpness by the inner blade 2 as shown by a in FIG. 3 (a). When the angle is 50 ° or less, the minimum plate thickness t ′ at the constricted portion due to the provision of the hitching portion 23 for reducing the cutting edge angle β becomes too small, and the base material 21 having high toughness is formed.
Although the bending strength is higher than that of stainless steel because it consists of a high hardness oxide film 22 deposited and formed on its surface, the strength of the constricted part (B in Fig. 3 (a)) is extremely high. Because it will be small. The plate thickness t of the inner blade 2 is 0.1 to 0.2 mm. Further, it is preferable that the cutting edge angle α of the outer blade 1 is also within the same range as the cutting edge angle β of the inner blade 2.

In FIG. 4, the cross section of the catch 23 has an arcuate shape, so that the minimum plate thickness t'at the constricted part is ensured with a predetermined cutting edge angle β, and the catch 23 has a V-shaped cross section. It shows that it can be made larger than in some cases. Further, FIG. 5 shows a structure in which a constricted portion is prevented from being formed in the middle of the inner blade 2 by grinding after the tip of the inner blade 2 has a Y-shaped cross section, and FIG.
The cross-sectional shape of is shown in a sawtooth shape. As shown in FIG. 7, the inner blade 2 may be bent to one side by bending, and the grip portion 23 may be formed only on the surface on the other side. In this case, although the beating portion 23 is formed on only one surface, both the cutting edges can have the required cutting edge angle β, and the minimum plate thickness t ′ can be increased.

In the above embodiment, the inner blade 2 for a reciprocating electric shaver having the cutting edges on both sides is shown, but FIG. 8 shows the inner blade 2 for the rotary electric shaver having the cutting edge only on one side. Shows. The required cutting edge angle β is obtained by bending the inner blade 2, but it may be ensured by providing a catching portion 23 as shown in FIG. 9. FIG. 10 shows an example in which the outer blade 1 is also formed of the base material 11 and the oxide film 12 having the same composition as the inner blade 2.

11 to 13 show the outer blade 1 and the inner blade 2 described above.
1 shows an example of a reciprocating electric razor using a. The outer blade 1 has float plates 15, 15 attached to both ends of the outer blade 1 between an outer surface of an outer blade holding base 16 and a cover 17 fixed to the outer surface. The float plate 15 is movably attached by being held so as to be vertically movable. A large number of inner blades 2 are attached to the inner blade base 25. The inner blade base 25 has a predetermined range on the upper end of the connecting boss 40 projecting from the driver 4 for converting the rotation of a motor (not shown) arranged in the main body 3 into a reciprocating motion. In the state in which the vertical movement in the inside and the inclination in the left-right direction in FIG. 13 are freely connected, and in the state of being urged upward by the push-up spring 46 arranged between the upper end surface of the boss 40. It is connected.

The boss 40 here has spherical projections 41 on both sides in the longitudinal direction of the inner blade base 25, which is the reciprocating direction of the inner blade 2, and on the front and rear surfaces in the width direction of the inner blade base 2. When the upper end portion of the boss 40 is inserted into the lower cylindrical portion of the inner blade base 25, the inner rib base 25 has the reinforcing ribs 48 and the engaging protrusions 42 connected to the upper ends of the reinforcing ribs 48. By engaging the formed hooks 26, 26 with the engaging projections 42, the inner blade base 25 is prevented from coming off against the bias of the push-up spring 46, and the projections 41 are provided on the inner surface of the inner blade base 25. By contacting
Reciprocating motion is transmitted from the driver 4 to the inner blade base 25. In this connection structure, the thickness of the boss 25 can be increased as compared with the case where the hook is provided on the boss 40 side, and the electric razor can be made thinner in general and a plurality of inner blade bases 25 can be arranged in parallel. Even if the width D of the blade base 25 is reduced, the boss 25 can be provided with sufficient strength.

14 and 15, the hooks 26, 26 provided on the lower portion of the inner blade base 25 are arranged on both sides of the inner blade base 25 in the longitudinal direction, and the rod 26 of the boss 40 with which the hook 26 engages. The engaging projections 42, 42 are arranged below the projection 41.

[0018]

As described above, in the present invention, since the oxide film deposited on the surface has a high hardness, no burrs are formed on the cutting edge when the grinding for forming the cutting edge is performed, and The blade angle can maintain the strength required for the blade without cutting, and at the same time the cutting resistance is within a small range, and the beard can be cut cleanly. Good sharpness can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment.

FIG. 2 (a) is a cross-sectional view showing an operation during cutting of a beard as above.
(b) is a perspective view showing a cut surface of the cut beard.

FIG. 3 (a) is an explanatory view showing a relationship between a cutting edge angle, sharpness and strength, and FIG. 3 (b) is a sectional view.

FIG. 4 is a cross-sectional view showing another example.

FIG. 5 is a sectional view showing still another example.

FIG. 6 is a sectional view showing another example.

FIG. 7 is a cross-sectional view showing still another example.

FIG. 8 is a cross-sectional view of another embodiment.

FIG. 9 is a cross-sectional view showing another example of the above.

FIG. 10 is a sectional view of another embodiment.

FIG. 11 is a sectional view.

FIG. 12 is an exploded perspective view of an inner blade base, a driver, and a push-up spring.

FIG. 13 is a cutaway front view showing a connecting portion between an inner blade base and a boss of a driver.

FIG. 14 is an exploded perspective view of an inner blade base, a driver, and a push-up spring in another example.

15A is a cutaway front view showing a connecting portion between an inner blade base and a boss of a driver, and FIG. 15B is a side view.

FIG. 16 is a sectional view of a conventional example.

FIG. 17 (a) is a cross-sectional view showing an operation during the cutting of the beard,
(b) is a perspective view showing a cut surface of the cut beard.

[Explanation of symbols]

 β Cutting edge angle 2 Inner blade 22 Oxide film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Mamoru Hamada, 1048, Kadoma, Kadoma, Osaka Prefecture, Matsushita Electric Works Co., Ltd.

Claims (1)

[Claims] 1. Cr: 25-35% by weight, Ni: 15-15
25% by weight, Al: 4 to 8% by weight, Ti: 0 to 0.5% by weight, at least one element of Zr, Y, Hf, Ce, La, Nd and Gd: 0.05 to 1.0 It is characterized in that it is made of a Fe-Cr-Ni-Al ferrite alloy in which the balance is Fe and the balance is Fe, and that it is formed as an oxide film deposited on the surface, and the cutting edge angle is 50 to 85 °. Electric razor blade.