JPS6323794B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a shearing blade for an electric hair clipper that is light in weight to reduce the load.

[Conventional technology]

Generally, in this type of hair clipper, the shearing blades, that is, the entire movable and fixed blades are made of metal such as knife steel or tool steel, and the spring force of the pressing spring that presses the movable blade against the fixed blade is Compared to electric razors, which are 200g to 400g.
Due to the large setting of around 1000g, the blade tip of the movable blade and the blade tip of the fixed blade during reciprocating motion,
A large amount of sliding heat is generated. By the way, the sliding heat of an electric razor is around 200℃ at most, while this type of hair clipper has a sliding heat of around 200℃ at most.
The temperature reaches 600-700℃.

[Problem that the invention seeks to solve]

However, if only the cutting edge portion is made of cutter steel or tool steel, the heat dissipation of sliding heat is poor, and unless some kind of heat-resistant structure is taken into account, the cutting edge portion will seize. If a chipping occurs at the cutting edge due to this seizure, the chipping from the direction of precipitation, which is unique to crystal growth, results in a large chipping of about 50 μm. As is well known, the diameter of hair is approximately 150μ, so if such a large blade spill occurs,
This can lead to hair tearing, which can lead to split ends and skin damage.

[Means for solving problems]

This invention was made in view of the above circumstances,
Of the cutting edge portion formed at the tip of the movable and fixed blade base and the abutment portion formed at the rear end, the cutting surface of at least the blade tip portion is Co11 to Co13 by weight ratio.
Of course, it is possible to obtain excellent wear resistance and heat resistance by constructing the cemented carbide with a composition of 1% to 2% Ta, and the balance being WC of 1 to 10μ, but for some reason For example, even if the blade spills due to the impact received when the cutting edge part bites into sand particles attached to hair, the composition of the cutting edge surface is particularly high, with a weight ratio of Co11 to 13% and Ta1 to 2.
% and the remainder is WC, and the particle size of this WC is 1 to 10μ to improve impact resistance.
This allows for excellent cutting edge precision.

Furthermore, this cutting edge precision is achieved by having a fine grain size as mentioned above, and the Ta component plays an important role in suppressing the grain growth of the fine grain WC. . In this manner, the present invention can provide an optimal configuration for the shearing blade of an electric hair clipper.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numerals 1 and 2 denote movable and fixed blade bases, respectively, which are made of synthetic resin with high mechanical strength such as polyacetal resin. 3 is a comb-shaped cutting edge formed at the tip of the movable blade base 1, and 4 is a comb-shaped cutting edge formed at the tip of the fixed blade base 1. Both cutting edge parts 3 and 4 are made of cemented carbide. There is. These cutting edge portions 3 and 4 are fixed to the respective base bodies 1 and 2 by simultaneous molding. The cemented carbide may be a well-known cemented carbide made by mixing TiC, TaC, etc. with a binder such as Co, and sintering the mixture, in addition to the WC type.

By making the movable and fixed blade bases 1 and 2 made of synthetic resin, the weight of the shearing blade itself is reduced, the load can be reduced and vibrations can be prevented, and the biasing force of the pressing spring is the greatest. Some of the above-mentioned cutting edge portions 3,
Since 4 is made of cemented carbide, it has high wear resistance, and even if the heat dissipation of sliding heat decreases, the heat resistance is high at around 1400°C, so the blade edges 3 and 4 are made of cemented carbide. Burn-in can be prevented.

Next, the chemical components of the cemented carbide that can further improve the sharpness and strength of the cutting edge portions 3 and 4 will be shown.

Co (cobalt) 1.2% Ta (tantalum) 1.5% WC (tungsten carbide) balance Generally speaking, the size of the WC particles in cemented carbide affects performance such as sharpness. The binder metal between each grain becomes smaller as the grain size decreases.
The boundary layer due to Co becomes thinner, improving wear resistance,
The precision of the cutting edge is increased. Conversely, as the particle size increases,
The boundary layer becomes thicker and the impact resistance improves, but on the other hand, the precision of the cutting edge decreases. However, in the case of the shearing blade of this example, since hair is to be sheared, the precision of the cutting edge is more important than the impact resistance, and the
Microparticles of WC, preferably 2μ microparticles of WC, are used.

As is well known, the binder metal Co influences the mechanical properties of cemented carbide. It has the contradictory characteristics that as the amount of Co increases, toughness increases, but wear resistance decreases. Normally, a Co content of 5 to 8% is often used, but in this example, since the WC particles are fine particles as mentioned above, a Co content of 5 to 8% mentioned above poses a problem in toughness. Therefore, the amount of Co is set at 12% to ensure the necessary toughness in the shearing blade.

Ta is used to suppress the growth of WC fine particles, and is included at 1.5%. This growth inhibiting effect is due to the following.

As mentioned above, the WC
The particle size was selected to be 2μ, but this value was
WC with a particle size of 2μ binds to each other and the crystals enlarge,
It becomes impossible to sharply cut hair of about 150μ. Therefore, by adding a small amount of Ta, preferably 1.5%, grain growth is suppressed, and in this example, the optimum grain size of WC can be maintained.

Co and Ta are added to the WC fine particles, which are compression molded and then sintered. During this compression molding, paraffin is added to improve moldability. For fastening, first, preliminary fastening is performed at around 800℃, then main sintering is performed at around 1400℃, which is close to the melting point of Co, and finally, the cutting edge part 3 is ground by grinding.
Grind 4.

The cutting edge parts 3 and 4 of the cemented carbide obtained by sintering the above WC, Co and Ta are fixed to the respective tips of the movable and fixed blade bases 1 and 2, and as a result of sliding, the sliding is relatively high. Although dynamic heat was generated, no seizure was observed due to the high heat resistance characteristic of cemented carbide.

Furthermore, regarding the blade spillage on the cutting edge parts 3 and 4,
There were no defects to the extent that roughness was visible to the naked eye, and microscopically it was confirmed that the precision of the cutting edge was higher than that of conventional cutting edges. This is because the particle size of the WC is set to about 2μ, so even if there is a loss, it is thought that it is naturally suppressed to the same size as this.

By the way, as mentioned above, the spring force of the pressing spring in this type of hair clipper is concentrated in this part in order to improve the adhesion between the cutting edge parts 3 and 4, and is concentrated on each of the movable and fixed blade bases 1 and 2. The rear end contact parts 5 and 6 are made of heat-resistant and wear-resistant synthetic resin so that the influence on sliding can be ignored. If the contact parts 5 and 6 are also made of cemented carbide, it becomes easy to limit the material such as the resin described above.

Further, in the above embodiment, the entire blade edges 3 and 4 are made of cemented carbide, but it is the opposing cutting surfaces 7 and 8 of these blade edges 3 and 4 that shear the hair. Considering this, as shown in Figure 3,
These cutting surfaces 7 and 8 may be made of cemented carbide, and in this case, the total weight of the shearing blade can be further reduced.

〔effect〕

As described in detail above, the present invention provides cutting edge portions 3 and 4 formed at the tips of movable and fixed blade bases 1 and 2.
Among the abutting parts 5 and 6 formed at the rear end, at least the cutting surfaces 7 and 8 of the cutting edge parts 3 and 4 have a weight ratio of 11 to 13% Co, 1 to 2% Ta, and the remainder 1 to 2%.
Constructed of cemented carbide with a composition of 10μ WC, it increases wear resistance and improves the precision of the cutting edge, and also has heat resistance to the extent that it is not affected by sliding heat, ensuring strength of the cutting edge. It is possible to provide a shearing blade for an electric hair clipper that can suppress blade spillage.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a shearing blade of an electric hair clipper according to the present invention, and FIGS. 2 and 3 are sectional views showing different deformed structures of the waist portion of the same shearing blade. DESCRIPTION OF SYMBOLS 1... Movable blade base body, 2... Fixed blade base body, 3, 4... Blade tip part, 5, 6... Rear end contact part, 7, 8... Cutting blade surface.

Claims (1)

[Claims] 1. Blade edge parts 3, 4 formed at the tips of the movable and fixed blade bases 1, 2, and a contact part 5 formed at the rear end.
6, at least the cutting surfaces 7 and 8 in the cutting edge portions 3 and 4 have a weight ratio of Co11 to 13% and Ta1 to
The electric hair clipper's shear blade is made of cemented carbide with a composition of 2% WC and 1 to 10μ WC.