JPH05200171A - Electric razor - Google Patents

Abstract

PURPOSE:To enable speedy shaving of beard with limited stimulation by arranging a correction circuit to restrict reduction in the number of revolutions to always obtain a better cutting performance in an electric razor adapted to control the number of revolutions of a motor according to the density of the beard. CONSTITUTION:When a switch SW is closed, after the start of a timer for measuring fine time, a control circuit 4 picks up a peak value from a current detection circuit 3 until a specified time passes to set the maximum value to the maximum peak value from the peak values picked up and determines a peak density by counting the frequency at which the peak value exceeding a specified value is generated. Then, when the specified time passes, the number of revolutions to set from a number of revolutions table based on the maximum peak value and the peak density. When the number of revolutions is larger than the preceding value, a motor M is driven at the number of revolutions. When the number of revolutions is smaller, the motor is driven at the number of revolutions smaller by one order from the preceding value only when this condition continues a plurality of times. Otherwise, the motor M is driven at the number of revolutions the same as the preceding value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric razor for detecting a darkness of a beard and driving a motor at a rotation speed corresponding to the darkness of a beard.

[0002]

2. Description of the Related Art As a motor used for an electric shaver, one having a constant voltage is conventionally applied,
In some cases, the motor speed is kept constant by feeding back the motor speed.

[0003]

In the former case, when the beard is thick, the load torque increases and the rotation speed decreases, so that good sharpness cannot be obtained. However, if the beard is dark and the motor rotation speed is set to a high value, the person with a thin beard is too stimulating.

In the latter case, stable sharpness can be obtained even if the load torque varies, but the motor rotates at the same number of revolutions regardless of whether the beard is thick or thin. You will not be able to shave well due to lack, and it will take time to shave again. And when the beard is thin, there is a problem that the stimulation is strong. For this reason, it is conceivable to determine the darkness of the beard from the motor current and drive the motor at a rotation speed according to the determined darkness of the beard. In this case, the rotation speed N of the motor changes as shown in FIG. 7 according to the darkness of the beard. However, the beard is dense and dense depending on the place, and the beard is also dense and shaved where it is already shaved. Therefore, if the beard density is simply determined from the motor current and the number of revolutions is controlled, it is possible to move from a beard-bearing location to a beard-free location and then shave another beard-bearing location. , The motor rotation speed suddenly decreases when moving to a place without a beard,
After that, it takes time until the number of rotations of the motor reaches a value corresponding to the darkness of the beard at the time of moving to a beard-bearing portion.

The present invention has been made in view of the above points, and an object of the present invention is to always obtain a good sharpness because the motor rotates at a rotational speed according to the darkness of the user's beard. The purpose is to provide an electric razor that can be shaved quickly and with less irritation.

[0006]

SUMMARY OF THE INVENTION However, according to the present invention, in an electric shaver that determines the thickness of a beard from the motor current and controls the motor rotation speed according to the darkness of the beard, the reduction amount of the rotation speed is limited. It is characterized by having a correction circuit that gives

[0007]

According to the present invention, the depth of the beard is automatically determined according to the motor current of the motor, which is the power for shaving, and the motor is driven at an appropriate number of rotations according to this depth,
Responsiveness of increase in motor speed at the time of shaving the next dark beard because the amount of reduction in motor speed when shaving a thin beard or shaving no beard is small Is a good one.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the illustrated embodiments. In the figure, 2 is a motor for driving an inner blade of an electric razor blade, and a motor current detecting resistor R is connected in series to the motor 2. Are connected. The resistor R constitutes the current detection circuit 3 which outputs the magnitude of the motor current as a voltage value together with the voltage amplification circuit 32 and the A / D conversion circuit 33, and outputs an electric signal according to the magnitude of the load when shaving. To do. Since the load when shaving is the largest at the moment when a large number of beards are cut at the same time, when the change in the motor current is seen, it has some peaks.

This electric signal is input to the control circuit 4. The control circuit 4 is mainly composed of a microprocessor, and has a peak detection circuit 41 that holds the maximum value Vm of the peak values Vp within a certain time T and a peak density detection circuit that counts the number of peaks within a certain time T. 42, switch SW
Of the switch ON detection circuit 43 for detecting ON / OFF of the motor (ON / OFF of the motor 2), and the motor rotation speed to be set is obtained from the outputs of the peak detection circuit 41 and the peak density detection circuit 42, and the speed instruction signal is sent to the rotation speed control circuit 5. It is formed by the output rotation speed selection circuit 44, and the motor rotation speed is increased when it is determined that the beard is dark from the maximum peak value and the peak frequency, and the rotation speed of the motor is determined when it is determined that the beard is thin. make low. However, when lowering the rotation speed of the motor 2, the rotation speed is not unconditionally lowered according to the thinness of the beard, but only when the state in which it is determined that the beard is thin continues several times. It limits the number by one.

More specifically, as shown in FIG. 2, when the switch SW is turned on, the control circuit 4 starts the timer t for minute time measurement and then elapses until the time T elapses. , The peak value Vp is fetched from the current detection circuit 3, the maximum value of the fetched peak values Vp is set to the maximum peak value Vm, and the number of times of occurrence of the peak value Vp equal to or more than the predetermined value Vo is counted. Then, the peak density is obtained. Then, when the time T has elapsed, the rotation speed N to be set is obtained from the rotation speed table based on the maximum peak value Vm and the peak density, and when this rotation speed N is higher than the previous rotation speed Np, It is instructed to drive the motor 2 at the rotation speed N.

However, when the rotation speed N obtained from the rotation speed table is lower than the previous rotation speed Np, the previous rotation speed Np can be obtained only when this state occurs a plurality of times Cs continuously.
If the motor 2 is instructed to be driven at a rotation speed N that is one step lower, and if the motor 2 is not continuously operated multiple times, the previous rotation speed N
It is instructed to drive the motor 2 at the same rotation speed N as p.

Therefore, when it is determined from the motor current that the beard is dark, the motor M is immediately set to a higher rotation speed and driven in this state, and the state in which it is determined that the beard is thin continues for a plurality of times. In this case, the motor M is driven at a slightly lower rotational speed than before, and an example of the rotational speed change is shown by the solid line in FIG. The broken line shows the change in the number of revolutions when the number of revolutions N is not limited.

As shown in FIG. 3, the above-described rotation speed table increases the rotation speed when the maximum peak value Vm is large, lowers the rotation speed when the maximum peak value Vm is small, and increases the peak density. If the peak density is low, the rotation speed will be low. Further, lowering the number of revolutions by one step means that when the previous number of revolutions Np is set to a in the figure, it is changed to b or c.

Although the motor 2 is rotated during shaving, there are cases in which the shaving is not actually performed because the electric razor is separated from the skin. At this time, it is preferable to drive the motor 2 at the minimum rotation speed in terms of noise and power consumption, but it takes a considerable time for the rotation speed of the motor 2 to fall to the minimum rotation speed under the above-mentioned limitation. Will end up. The embodiment shown in FIGS. 5 and 6 deals with this point. Here, when the rotation speed N obtained from the darkness of the beard is lower than the previous rotation speed Np, the rotation speed N is close to the minimum rotation speed. It is further determined whether or not the value is Ns or less. When the value is Ns or less, when Co continues for a plurality of times, the motor 2 is driven at a rotation speed N much lower than the rotation speed Np up to then without restriction. Immediate transition. The solid line in FIG. 6 shows the change in the rotation speed N when this process is applied, and the broken line shows the change in the rotation speed N when no limitation is imposed on the reduction of the rotation speed.

[0015]

As described above, according to the present invention, the depth of the beard is automatically determined according to the motor current of the motor, which is the power for shaving, and the motor is driven at an appropriate number of revolutions according to this depth. Therefore, when the beard is thick, the torque is insufficient to shave well, and when the beard is thin, the stimulus is not too strong, and a good sharpness can always be obtained with little stimulation. Yes, and because the amount of reduction in the motor rotation speed when the beard is thin or the shave is to be shaved is limited, the motor rotation at the time when the next dark shave is to be shaved Responsive to the increase in the number, it is possible to shave quickly.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment.

FIG. 2 is a flowchart of the operation of the embodiment.

FIG. 3 is an explanatory diagram of a rotation speed table.

FIG. 4 is an explanatory diagram showing a change in rotation speed.

FIG. 5 is a flowchart of the operation of another embodiment.

FIG. 6 is an explanatory diagram showing a change in rotation speed of the above.

FIG. 7 is an explanatory diagram showing a change in rotation speed of a conventional example.

[Explanation of symbols]

 M motor 3 current detection circuit 4 control circuit 5 rotation speed control circuit

Claims (2)

[Claims] 1. An electric razor for determining the darkness of a beard from the motor current and controlling the motor rotation speed according to the darkness of the beard includes a correction circuit for limiting a reduction amount of the rotation speed. A featured electric razor. 2. The electric razor according to claim 1, wherein the correction circuit releases the restriction depending on whether or not the shaving operation is performed.