JPH0547230B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to the improvement of rotating or vibrating electric shavers, and particularly aims to provide outer cutters with excellent wear resistance.

[Background of the invention]

The outer blades used in conventional electric razors are
Since it is made from nickel electroforming and thin stainless steel sheets, if used for a long time, it will discolor due to sweat and other factors, reducing the product's value. In particular, due to sliding friction between the outer cutter and inner cutter, a solid solution layer is formed between the two metals,
The area of the sliding surface increases due to wear, resulting in a large frictional resistance, a large sliding load, and an increase in power consumption.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the prior art and to provide an electric shaver that has excellent durability and low sliding resistance.

[Summary of the Invention] In order to achieve this object, the present invention forms a titanium nitride film on at least the sliding surface of the outer cutter and the inner cutter, and sets the titanium nitride film structure molar fraction to nitrogen to titanium. This was achieved by setting the ratio to be in the range of 0.4:1 to 0.8:1.

The titanium nitride film can be created by high-frequency sputtering, magnetron sputtering, ion plating CVD, plasma CVD, etc. In sputtering, the ratio of argon gas to nitrogen gas and the high-frequency power are By controlling it, a desired nitrogen content can be obtained. On the other hand, in the ion plating method, the nitrogen content is controlled by controlling the titanium precipitation rate and the ratio of nitrogen or ammonia.

Particularly when using the sputter method, the total gas pressure of argon and nitrogen gas is preferably 0.003 to 0.3 Torr; below 0.003 Torr, no discharge occurs, and above 0.3 Torr, the discharge becomes unstable. Also, the high frequency power is 1~
5W/cm ² is desirable; below 1W/cm ² the deposition rate is too slow and the efficiency is poor; above 5W/cm ² the deposition rate is saturated and does not increase at all, causing an increase in target temperature and substrate temperature. Just doing so will have an adverse effect on the outer blade base material, such as lowering its mechanical strength.

The thickness of such a titanium nitride film is preferably in the range of 100 to 300,000 Å from the viewpoint of corrosion resistance; if it is less than 100 Å, the film will not be effective, and if it is more than 300,000 Å, the outer cutter will deform, which is not desirable. In particular, a range of 300 to 100,000 Å is desirable.

[Embodiments of the invention]

Examples of the present invention will be described below.

Example 1 This FIG. 1 is a schematic diagram of the high frequency sputtering apparatus used in Example 1, in which 1 is argon gas, 2 is nitrogen gas, 3 is a heater, 4 is a substrate,
5 is a titanium target, 6 is a high frequency power source, and 7 is an exhaust gas.

A predetermined number of outer blades 8 made of nickel electroformed blades are attached to the substrate 4.
After using titanium as the target 5 and reducing the pressure in the processing container 9 by the exhaust 7, the outer blade 8 is heated to approximately 100°C by the heater 3, and the high frequency power source 6 is set to an output of 3W/cm. ² Sputtering was performed by varying the gas pressure ratio of argon gas 1 and nitrogen gas 2 while keeping it constant to create a titanium nitride film with a thickness of 0.5μ, and the composition ratio of titanium and nitrogen in this film was varied. An outer edge was formed.

Example 2 FIG. 2 is a schematic diagram of a high-frequency ion plating apparatus used in Example 2, in which the same symbols as those in FIG. 1 indicate the same parts, 10 is a high-frequency power source, 11
12 is a DC power supply, 12 is a high-frequency coil, 13 is titanium, 14 is an electron gun, and 15 is a processing container.

As in Example 1, the nickel electroformed outer blade 8 is held on the substrate 4, the output of the electron gun 14 is set to 3KW to evaporate titanium, and the pressure of the argon gas 1 is set to 1×.
A titanium nitride film with a thickness of 0.5 μm was formed under the following conditions: 10 ⁻⁴ Torr, nitrogen gas 2 pressure of 6×10 ⁻⁵ Torr, high frequency power of 200 W, and applied voltage of 500 V.

The mole fraction of nitrogen to titanium in the film prepared at this time was
The ratio was 0.7:1.

Comparative Example 1 Titanium nitride was produced under the same conditions as in Example 2 except that the nitrogen gas pressure was changed to 1×10 ⁴ Torr. At this time, the molar ratio of nitrogen to titanium in the nitride film was 1.

[Effects of the Invention] An electric shaver was assembled using the outer cutter produced above, the drive current was measured, and the results were compared with the measurement results of the drive current after further use for 50 hours.

FIG. 3 shows the measurement results for the samples prepared in Example 1 with different ratios of titanium and nitrogen.

In FIG. 3, the horizontal axis shows the mole fraction, and the vertical axis shows the driving current. As can be seen from this figure, although the driving current initially decreases as the nitrogen content increases, after 50 hours of use, the mole fraction decreases.
A value between 0.4 and 0.8 is good with little change compared to the initial value, and the drive current is large even when the nitrogen content is 0.3% or less or 0.9 or less.

In addition, as a result of assembling an electric razor using the outer blade produced in Example 2 and measuring the driving current in the same manner,
Initially it was 420mA, and after 50 hours of use it was 430mA.

Next, Comparative Example 1 was also measured in the same way, and the initial
It was small at 410mA, but after 50 hours of use, it showed an increasing trend to 500mA.

Incidentally, in both the above embodiments and comparative examples, a rotary dome-shaped outer cutter was used, but it goes without saying that the same applies to a reciprocating reticulated outer cutter.

Furthermore, forming a titanium nitride film not only on the sliding surface but also on the side that comes into contact with the skin has the effect of protecting the nickel surface and eliminating fading and discoloration.

Furthermore, although a nickel electroformed blade is used as the outer blade base material, the same effect can be obtained by using a nickel-cobalt alloy electroforming or a stainless thin steel plate.

As mentioned above, the mole fraction of nitrogen to titanium is
By setting the ratio between 0.4:1 and 0.8:1 and forming a titanium nitride film on at least the sliding surface of the outer cutter,
Even if used for a long time, the increase in drive current is suppressed and the load current is suppressed, resulting in an outer blade with a long life.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of an example of a sputtering apparatus for carrying out the present invention, FIG. 2 is a schematic explanatory diagram of an example of the same ion plating apparatus, and FIG. 3 is a schematic explanatory diagram of an example of the same ion plating apparatus. FIG. 3 is a characteristic diagram showing the results of measuring the value of drive current with respect to the ratio.

Claims (1)

[Claims] 1. An electric shaver using an outer cutter on which a titanium nitride film with a nitrogen to titanium molar ratio of 0.4:1 to 0.8:1 is formed on at least the sliding surface with the inner cutter.