JPH0785756B2 - Reciprocating electric razor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a reciprocating electric shaver.

BACKGROUND ART A reciprocating electric shaver that shaves by reciprocally vibrating an inner blade includes a plate-shaped piezoelectric actuator that vibrates when a voltage is applied, and uses the vibration of the piezoelectric actuator to move the inner blade. It is configured to reciprocate.

As a device provided with such a piezoelectric actuator, there is one disclosed in Japanese Patent Publication No. 53-6586.

In the drive mechanism portion of such a reciprocating electric shaver piezoelectric actuator (vibrator), the end of the piezoelectric actuator is inserted into the notch formed in the piezoelectric actuator holding portion of the vibration transmitter and fixed by the casting resin. There is. The casting resin that fixes the vibrator end has elasticity.

However, in this way, in the method of fixing the end portion of the piezoelectric actuator in the cutout portion by the casting resin having elasticity,
If the elasticity of the casting resin is large, the fixed position of the end portion of the piezoelectric actuator is easily moved, so that the effect of transmitting the vibration force to the vibration transmitter is poor and the loss is increased. On the contrary, if the elasticity of the casting resin is low, the vibration direction of the piezoelectric actuator due to bending vibration and the reciprocating direction of the inner blade are different, so the end of the piezoelectric actuator is partially bent at its fixed part, and the vibration transmission still occurs. The loss will increase. When the elasticity of the cast resin is low, a large stress is further applied to the piezoelectric actuator, which may damage the piezoelectric actuator due to repeated vibration.

On the other hand, when the casting resin having elasticity is filled between the inner surface of the cutout portion and the outer surface of the end portion of the piezoelectric actuator, the resin fixing portion of the piezoelectric actuator is not limited to the longitudinal direction of the piezoelectric actuator but also the inner blade. It can also move back and forth. Therefore, the resin fixing portion of the piezoelectric actuator relatively moves in a direction opposite to the vibration direction of the piezoelectric actuator (moves away from the vibration direction) with the root of the portion protruding from the resin fixing portion of the piezoelectric actuator as a fulcrum. Vibration transmission loss due to this movement also occurs.

[Object of the Invention]

Therefore, an object of the present invention is to provide a reciprocating electric shaver that solves the above problems and reduces vibration transmission loss to improve vibration efficiency.

[Disclosure of Invention]

In order to achieve the above object, the present invention provides a piezoelectric actuator that vibrates when a voltage is applied, a vibration transmission body that is connected to the piezoelectric actuator and that transmits the vibration of the piezoelectric actuator, and an inner blade attached to the vibration transmission body. And a reciprocating electric razor provided with an outer blade that is stretched over the upper portion of the razor body and the inner blade is in sliding contact with the inner surface,
The piezoelectric actuators are plate-shaped and each pair is arranged in parallel and arranged in parallel with each other. One of the pair is connected to the vibration transmitter by a loose fitting structure that is relatively slidable in the longitudinal direction. The main point is a reciprocating electric razor, which is characterized by being used.

The present invention will be described below with reference to the drawings showing an embodiment thereof.

In FIG. 1, reference numeral 1 is a device body, and an outer blade mounting base 2 is attached to the outer periphery of the upper end thereof. Outer blade mount 2
The outer blade 3 is attached to the opening formed in the upper part of the. A large number of whisker introduction holes (not shown) are formed in the outer blade 3. An inner blade 4 is reciprocally slidably provided inside the outer blade 3, and its direction is the left and right direction in FIG.

On the other hand, the structure for driving the inner blade 4 in a reciprocating manner is as follows.

That is, as shown in detail in FIGS. 2 (a) and 2 (b), 5 is an actuator mounting piece, which is fixed to the device body 1 as a pair. A pair of piezoelectric actuators 6 is fixed at the lower end thereof by press fitting or the like. The piezoelectric actuators 6 each have a plate shape and project upward, and are arranged in parallel with each other.
Reference numeral 7 denotes a support shaft, which is also fixed to the device body 1, and a vibration transmission body 9 is supported by fitting a rotary support boss 8 to the support shaft 7. The vibration transmitter 9 has a rotary vibrating portion 10 having a rotary support boss 8 in an intermediate portion, and a linear vibrating portion 11 arranged horizontally below the rotary vibrating portion 10.
A constricted flexible joint portion 12 is provided between the flexible joint portions 12 to provide flexibility. Both shoulders of the linear vibration part 11
13, 13 are press-fitted and connected to the upper end of each piezoelectric actuator 6, while the upper end of the rotary vibration part 10 is connected to the inner blade 4 of FIG. 1 via a connecting pin 23 (see FIG. 4 (a)). Are linked together.

When the piezoelectric actuator 6 is applied with a voltage, X in FIG.
When reciprocally oscillated in the direction, the linear oscillating portion 11 connected thereto is also driven in the arrow X direction, and the rotary oscillating portion 10 moves the support shaft 7 through the flexible joint portion 12 along with the oscillator. It rotates in the Y direction around the center and reciprocally vibrates.
As a result, the inner blade 4 (Fig. 1) vibrates.

This reciprocating electric shaver uses a frequency conversion circuit to convert the commercial frequency power supply to a frequency higher than the commercial frequency.
14 is provided as shown in FIG.

The details are shown in FIG. 2 (a). That is, 15 is a commercial frequency power supply, the frequency of which is 50 to 60.
Hz, and 16 is a device switch, a rectification block 17 for converting alternating current into direct current is provided on the circuit having the commercial frequency power supply 15 and the device switch 16, and the rectification block 17 is followed by direct current. A constant voltage circuit 19 for stabilizing the voltage is provided via a smoothing filter 18 for smoothing. Reference numeral 20 is an inverter unit, which oscillates direct current at 130 Hz to convert it into alternating current, and 21 is a sine wave filter that shapes the waveform into a sine wave.

In this way, the frequency conversion circuit 14 is configured and connected to each piezoelectric actuator 6.

According to the frequency conversion circuit 14, by the input operation of the device switch 16, the current from the commercial frequency power source 15 is converted into direct current by the rectification block 17 and the smoothing filter 18, and then is controlled to a constant voltage by the constant voltage circuit 19. After that, the inverter section
It oscillates at 130 Hz at 20 and is shaped into a sine wave by the sine wave filter 21. In this way, a voltage having a frequency of 130 Hz is applied to the piezoelectric actuator 6.

In the reciprocating electric shaver according to the present invention, the frequency (50 to 60 Hz) of the commercial frequency power source 15 is 130 H as described above.
Since it becomes z and is applied to the piezoelectric actuator 6, the inner blade 4 (FIG. 1) also vibrates faster based on a higher frequency, and obtains a cutting speed desired for this type of razor, The beard can be treated more effectively and sharply.

The increase / decrease width of the frequency can be changed by the variable resistor 22. Therefore, by operating the variable resistor 22, the output displacement of the piezoelectric actuator 6 changes, and the inner blade 4 (first The amplitude of (Fig. 1) also changes. For example, when shaving a long beard, the amplitude of the inner blade 4 is increased, and when finished short, the amplitude of the inner blade 4 is decreased,
It is possible to effectively shave each beard according to its characteristics. The lower limit of the frequency may be 90 Hz and the upper limit may be 150 Hz. That is, when the frequency is lower than 90 Hz, the effect of improving the sharpness is deteriorated, while when it is higher than 150 Hz, the vibration noise becomes excessive and the quality may be deteriorated.

In the above embodiment, the constant voltage circuit 19 is provided. However, if this is done, the applied voltage is kept constant, so that the variation rate of the displacement of the piezoelectric actuator 6 is suppressed to a low level, and the inner blade 4 (see FIG. The stabilization of the sharpness can be ensured by making the amplitude of) constant.

In the above embodiment, the resonance frequency of the vibration system between the piezoelectric actuator 6 and the inner blade 4, that is, the piezoelectric actuator 6, the vibration transmitter 9 and the inner blade 4, and the frequency applied to the piezoelectric actuator 6 are set. By making them coincide with each other, the amplitude of the inner blade 4 is increased and the sharpness is good,
We are trying to obtain an efficient vibration system.

Here, the resonance frequency f ₀ of the inner blade obtained in the vibration system of the above embodiment will be devised based on FIG. 4 (a) and FIG. 4 (b) showing its model diagram. In FIG. 4 (a), G
Indicates the position of the center of gravity of the whole including the inner blade 4 and the rotary vibration part 10, and in FIG. 4 (b), M is the mass including the inner blade 4 and the rotary vibration part 10, and m is The mass of the vibration transmitting body 9 excluding the rotational vibrating portion 10 is shown. Furthermore, as shown in FIG.
In (b), l is the dimension between the center of gravity G and the center of the support shaft 7, l ₂ is the dimension from the center of the support shaft 7 to the linear vibration part 11, and K is The spring constants of four piezoelectric actuators 6 are shown.

Then, the resonance frequency is expressed by the following equation.

This resonance frequency f ₀ may be matched with the frequency applied to the piezoelectric actuator 6.

At the same time, in order to increase the amplitude of the inner blade 4, the following configuration may be adopted.

That is, in FIG. 4 (a), l ₁ is the connecting pin 23 and the inner blade member 4 and the vibration transmitting member 9 shows the center-to-center dimension between the support shaft 7 with respect to the l _1, the l ₂ Is shortened, and the ratio relation l ₁ / l ₂ > 1 is set.

When based on such a ratio relationship, the amplitude of the inner blade 4 is amplified, leading to improved sharpness.

Further, in this case, as shown in FIG. 5, the flexible joint portion 12 is formed as a pair of left and right elastic thin plate type, or, as shown in FIG. 6, a ball joint is provided at the lower end of the rotary vibration portion 10. 24 is formed and the ball joint 24 is fitted to the joint receiver 25 provided at the center of the linear vibrating portion 11, the vertical displacement is effectively absorbed and the amplitude of the inner blade 4 is further reduced. It is possible to obtain a larger size, and thereby, the sharpness can be satisfactorily obtained.

Here, if one of the piezoelectric actuators 6, which is located on one side (inside in this embodiment), and the vibration transmitting body 9 are connected by a loose fitting structure that is vertically slidable relative to each other, more resistance is provided. Can be reduced, which is advantageous for increasing the amplitude.

On the other hand, in the above, the case of using the commercial frequency power source has been exemplified, but as shown in FIG.
When using, the booster circuit 27, the inverter unit 20, and the sine wave filter 21 are configured as the frequency conversion circuit.

〔The invention's effect〕

As described above, according to the present invention, the piezoelectric actuators are plate-shaped and each pair is arranged in parallel and arranged in parallel with each other, and one of the pair is longitudinally connected to the vibration transmitter. Since it is connected by a loose fitting structure so that it can slide relative to each other, even if the vibration direction of the piezoelectric actuator and the inner blade reciprocating direction are different, due to the sliding in the longitudinal direction,
Since the piezoelectric actuator can be prevented from being partially bent and can slide only in the longitudinal direction of the piezoelectric actuator, it may escape in the direction opposite to the vibration direction at the press-fitting and fixing portion. It has good vibration transmission efficiency.

[Brief description of drawings]

1 is a vertical sectional front view of a reciprocating electric shaver showing an embodiment of the present invention, FIG. 2 (a) is a system diagram showing a vibration system and a frequency conversion circuit, and FIG. 2 (b) is a vibration system. Side view, second
FIG. 3C is a circuit block diagram of a frequency conversion circuit when a battery is used, FIG. 3 is an operation explanatory diagram of a vibration system, and FIG.
Is a front view of the vibration system for explaining the resonance frequency, FIG. 4 (b) is its vibration model view, FIG. 5 is a front view of the vibration system for increasing the amplitude of the inner blade, and FIG. 3 is a front view of a vibrating system showing the embodiment of FIG. 3 ... outer blade, 4 ... inner blade, 6 ... piezoelectric actuator,
10 …… Vibration transmitter

Claims (1)

[Claims] 1. A piezoelectric actuator that vibrates when a voltage is applied, a vibration transmitter that is connected to the piezoelectric actuator to transmit the vibration of the piezoelectric actuator, an inner blade attached to the vibration transmitter, and an upper portion of a razor body. In a reciprocating electric shaver having an outer blade that is stretched and has an inner blade slidably contacting the inner surface, the piezoelectric actuators are plate-shaped, and a pair of piezoelectric actuators are arranged in parallel with each other. A reciprocating electric shaver, wherein one of the pair is connected to the vibration transmitting member by a loosely fitting structure that is relatively slidable in the longitudinal direction.