JPH0214076B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an inner cutter for a rotary electric shaver in which a plurality of helical inner cutter blades are integrally formed on the circumferential surface of a tubular rotating body.

In a rotary electric shaver, if the inner blade is formed into a helical shape, there are advantages such as very little chatter, quiet rotation, good sharpness, and no depression of the outer cutter.

There are two ways to integrally form a helical inner blade with these advantages on the circumferential surface of a rotating body: first, cutting the circumferential surface of a tubular or rod-shaped material with a rotating grindstone, and rolling. There are two possible methods to obtain this, but these methods cannot be mass-produced and have low productivity. Next, as a method to enable mass production, an inner cutter having a helical inner cutter blade is extruded onto the circumferential surface of the tubular rotating body by extrusion processing, that is, extruding the billet material through a die. There are possible ways. According to this extrusion processing method, the material is extruded into a tubular body with a predetermined cross-sectional shape and twisted at the same time, but this extruded tubular body that becomes the inner cutter is thin, and in addition, it is difficult to extrude. If twisting is applied at the same time, defects such as cavities and cracks are likely to occur. This is because the heat generated by deformation and frictional work does not have time to escape, and furthermore, extrusion and twisting continuously generate heat, so the temperature rises rapidly. For this reason, materials that exhibit high-temperature brittleness, especially materials with structures with low melting points such as strong aluminum alloys, are prone to cracking on the surface, and the surface layer, which is severely deformed, tends to coarsen grains and reduce strength. It is in.

Focusing on this fact, the present invention separates the extrusion molding process of integrally extruding the rotary body of the inner cutter and the inner cutter blade, and the process of attaching a lead to the inner cutter blade, thereby making it possible to create a nest. It is an object of the present invention to provide a method for manufacturing an inner cutter for a rotary electric shaver, which enables mass production of high-quality inner cutters free from defects such as cracks.

The details will be explained below based on the drawings.

Figure 1 shows an example of the head part of a rotary electric shaver.
A mesh outer cutter 2 stretched in a semicircular shape is removably attached to an outer cutter holder 3, and a plurality of helical blades are provided on the circumferential surface of the tubular rotary body 4 at a constant angle with respect to the body axis. An inner cutter 6 integrally formed with an inner cutter blade 5 is provided so as to be able to slide and rotate against the inner surface of the outer cutter 2. The inner cutter 6 has a gear 8 fixed to one end of its shaft 7, and a drive gear 11 on a shaft 10 of a motor 9 built in the main body case 1 is transmitted to the gear 8 through a group of 12 reduction gears. , axis 7
rotate around.

The inner cutter 6 is manufactured as follows. first,
As shown in Fig. 3, a billet 13 made of aluminum or aluminum alloy, which is the material for the inner blade.
is charged into the container 14. The billet 13 is pressurized by the ram 15 and extruded from the outlet between the inner die 16 and the outer die 17. The outlet formed between the inner and outer dies 16 and 17 has a shape as shown in FIG.
A plurality of outward grooves 19 (six grooves in the illustrated example) protrude radially outward from several places on the outer periphery of the hole 18, and inward grooves 19 protrude radially inward from several places on the inner periphery of the hole 19. It has grooves 20 (two grooves in the illustrated example). Therefore, during extrusion, the billet 13 has an annular hole 18 at the outlet of the inner and outer dies 16, 17;
From the outward groove 19 and the inward groove 20, fin-like pieces 21 parallel to the tube axis direction are formed on the inner and outer peripheries as shown in FIG.
A tubular body 23 having a diameter of 22 is formed and extruded.

Tubular body 23 extruded into such a cross-sectional shape
is inserted into a die mold 24 for attaching a lead as shown in FIG. The tubular body 23 is inserted so that it fits into a locking shape, and is pushed out below the die 24 while applying twist to the tubular body 23. The hole of the die mold 24 has a shape as shown in FIG. 6, and has a plurality of helical grooves 26 on the inner periphery that are inclined at a constant angle with respect to the axial direction. Each helical groove 26 has an inlet end 26a formed in a straight line parallel to the axial direction in order to facilitate insertion of the fin-like piece 22 into the helical groove 26 when inserting the tubular body 23. During extrusion, the tubular body 23 is twisted and extruded with a lead attached to the fin-like pieces 22.

Finally, the tip of the fin-like piece 22 is alumite-treated and then sharpened by applying it to a centerless sharpening abrasive grindstone. In this way, an inner cutter 6 is obtained in which the tubular body 23 becomes the rotating body 4 and the fin-like pieces 22 serve as the helical inner cutter blade 5.

As explained above, according to the manufacturing method of the present invention, the inner cutter 6 having the helical inner cutter blade 5 on the circumferential surface of the rotating body 4 can be mass-produced.

In particular, in this invention, first, a primary process is performed in which the tubular body 23 that becomes the rotary body 4 and the fin-like pieces 22 that are parallel to the tube axis direction that become the helical inner blade 5 are integrally extruded on the circumferential surface thereof. Then, in the next separate process, the tubular body 23 having the fin-like pieces 22 was passed through the die mold 24 to attach a lead to the fin-like pieces 22, so that the inner blade 5 was removed during the manufacturing process. It exerts its own cooling fin action, prevents deformation due to heat and decrease in strength due to coarsening of crystal grains, and stabilizes the material itself before attaching leads, resulting in a high-quality rotary rod without defects such as cavities or cracks. You can get the inner blade of an electric shaver.

[Brief explanation of drawings]

Figure 1 is a partial vertical sectional view illustrating a rotary electric shaver, Figure 2 is a perspective view of the inner cutter, Figure 3 is a sectional view of the billet being extruded through a die, and Figure 4 is Figure 3. Fig. 5 is a perspective view of the extruded tubular body, Fig. 6 is the rotating push rod, and the tubular body in a state before a lead is attached.
FIG. 3 is a perspective view showing a die mold for attaching a lead and a tubular body, that is, an inner cutter after attaching a lead. 4... Rotating body, 5... Inner cutter blade, 6... Inner cutter, 13... Billet, 14... Container, 15
... Ram, 16 ... Inner die, 17 ... Outer die, 22 ... Fin-like piece, 23 ... Tubular body, 2
4...Dice type, 26...Helical groove.

Claims (1)

[Claims] 1. When manufacturing the inner cutter 6 which is formed by integrally forming a plurality of helical inner cutter blades 5 that are inclined at a constant angle with respect to the barrel axis on the circumferential surface of the tubular rotating barrel 4, hot extrusion is used. By machining, the rotating body 4 of the inner cutter 6
At the same time as the tubular body 23 is extruded, a fin-like piece 22 that becomes the inner blade 5 of the inner cutter is integrally molded in parallel to the tube axis direction on the circumferential surface of the tubular body 23, and then the fin-like piece 22 is inserted into a die mold 24 having a plurality of helical grooves 26 inclined at a constant angle with respect to the axial direction on the inner periphery so that the fin-like pieces 22 are aligned with the inside of the helical grooves 26 and pressed. A method for manufacturing an inner blade of a rotary electric shaver, characterized by attaching a lead to a fin-like piece 22 by twisting the inner blade.