JPH0427511Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an electric shaver, and particularly to one in which the rotational speed of a motor that drives an inner cutter can be changed.

[Prior Art] It is known that the sharpness of an electric shaver usually changes in response to changes in the inner blade drive speed.

Based on this knowledge, conventionally, during normal use, a resistor was interposed between the power supply and the motor to lower the voltage applied to the motor and reduce the rotational speed of the motor. A device has been proposed that allows shaving to be completed at high speed by applying full power to the motor in conjunction with the switching operation of a switch for a certain period of time.

However, with the above configuration, during normal use, current constantly flows through the resistor, and the voltage drop across the resistor increases as the load increases and the current increases, resulting in a significant decrease in rotational speed, and the power loss due to the resistor. Losses also increase to such an extent that they cannot be ignored.

To solve this problem, by using a diode instead of a resistor and reducing the voltage applied to the motor by the forward voltage of the diode, fluctuations in rotational speed due to power loss or load fluctuations can be prevented as much as possible. Attempts have also been made to do so (for example, Japanese Patent Laid-Open No. 59-63996).

[Problems to be solved by the invention] However, the most preferable inner blade drive speed for each user varies depending on whether the user has a thick or thin beard or the area to be shaved. The voltage value that can be dropped is regulated by the value of the forward voltage of the diode, and the rotation speed can only be changed in steps, making it nearly impossible to select the optimal rotation speed for each user.

The present invention was developed in view of the above problems, and allows fine adjustment of the motor rotation speed with a simple configuration.
It is an object of the present invention to provide an electric shaver that can maintain a relatively stable rotational speed even with load fluctuations and can suppress power loss as much as possible.

[Means for Solving the Problems] Fig. 1 is a schematic diagram illustrating the basic configuration of the electric shaver according to the present invention, and is similar to the conventional electric shaver, with a motor 14 that drives the inner cutter and a motor 14 that drives the inner cutter. ,
It is provided with a power supply section 19 that supplies electric power to the motor 14, and a main switch 15 that regulates the starting timing of the motor 14.

The present invention is characterized in that, in addition to the above configuration, it includes a pulse signal generating section 20 and a switching section 21 that repeats on/off operations in conjunction with the input of the signal output from the pulse signal generating section 20. do.

The pulse signal generating section 20 is configured to be able to continuously change the ratio τ/T of the pulse width τ to each period T of the generated signal.

On the other hand, the switching section 21 is interposed in the energizing circuit for the motor 14, and controls the energizing circuit on and off in response to input pulse signals.

[Operation] In the above configuration, when the main switch 15 is turned on, power supply from the power supply section 19 to the motor 14 is started.

At the same time, the pulse signal generating section 20 sends a pulse signal to the switching section 21, and the switching section 21 repeatedly turns on and off the motor 1.
As shown by the dotted line in FIG. 4, the ratio of the pulse width τ to the time T of one cycle is τ/
An average voltage V _n having a value corresponding to T is substantially applied to the motor 14 . At this time, the pulse signal generator 20
Since the above ratio in the signal output from the motor 14 can be changed steplessly, the value of the average voltage V _n applied to the motor 14 can also be set arbitrarily, and the motor rotation speed,
Therefore, the driving speed of the inner cutter is selected to be the optimum value for each user.

[Example] The present invention will be described below based on an example implemented in a reciprocating type electric shaver using a dry battery as a power source, but it goes without saying that it can be implemented in various types of electric shavers such as a rotary type.

As shown in FIG. 2, the electric shaver embodying the present invention has an outer cutter 12 detachably attached to the upper part of a main body case 11, and an inner cutter 13 slidably disposed inside the outer cutter 12. A motor 14 for moving the inner cutter 13 is housed inside the main body case 11.

On the circumferential surface of the main body case 11, there is a sliding main switch 15 that regulates the starting timing of the motor 14;
A push-button sub switch 16 for changing the rotational speed of the motor 14 and a variable resistor 17 for finely adjusting the rotational speed are provided to enable manual operation of the control circuit 18 housed inside the main body case 11. do.

As shown in FIG. 3, the control circuit 18 includes a power supply section 19 that generates a predetermined DC voltage _V3 , a pulse signal generation section 20 that generates a predetermined pulse signal, and performs on/off operations in conjunction with the input of the pulse signal. It is composed of a switching section 21.

The power supply section 19 is made up of a plurality of batteries 22 connected in series, and is configured so that when an output voltage is directly applied to the motor 14, the rotational speed of the motor 14 is a value slightly higher than the required maximum speed. , output voltage
_V3 is set. The output side of this power supply section 19 is
It is connected in series with the main switch 15, motor 14, and switching section 21 to form a motor energization circuit.

The pulse signal generating section 20 is an astable multivibrator using two sets of transistors 23 and 24, and includes a variable resistor 17 between the base of the first transistor 23 and the positive electrode of the battery 22.
The charging time constant of the circuit can be changed, and the pulse width τ of the output signal can be changed as shown in Fig. 4, so that each period T
The ratio τ/T of the pulse width τ in the pulse width τ can be changed steplessly. Furthermore, a sub-switch 16 is provided between the base end and ground, and when the switch 16 is turned on, the base end of the first transistor 23 is forcibly brought to zero potential, thereby temporarily stopping the oscillation of the vibrator. However, the signal input to the switching section 21 is stopped by setting the potential at the output terminal to zero.

The switching section 21 has PNP type and NPN type transistors 25 and 26 connected in Darlington, and the emitter end of the first transistor 25 is connected to the positive side of the power supply section 19, and the base end and the pulse signal generating section 20 are connected to each other. By connecting the output end of the pulse signal generating section 20, the energizing circuit is regulated to be turned on or off in response to the output signal from the pulse signal generating section 20.

That is, at the same time as the main switch 15 is turned on, the pulse signal generating section 20 starts generating pulse signals, and the output pulse signal causes the switching section 21 to be activated.
is turned on and off, and the energizing circuit to the motor 14 is rapidly intermittent as shown in FIG _.
4 and the motor 14 rotates at a lower rotational speed than when the switching unit 21 is continuously turned on. At this time, by appropriately changing the resistance value of the variable resistor 17 provided on the peripheral surface of the main body case 14 to determine the optimum rotation speed for each user, the main switch 15 can be The optimum inner blade drive speed can be obtained with each press. On the other hand, sub switch 1
6, the level of the input signal to the switching unit 21 becomes zero, the transistor 26 of the switching unit 21 is turned on, and a voltage V _M lower than the power supply voltage V _P by the emitter-collector voltage of the transistor 26 is applied to the motor 14. The application is continued and the motor 14 is rotated at a higher speed than the above-mentioned optimum speed to perform shaving in the high speed mode.

In addition, the variable resistor 17 is installed so that the motor 14 cannot be set below the minimum rotation speed at which it can rotate stably.
By setting the value of the resistor 27 connected in series with the motor 14 in advance, there is no possibility that the motor 14 will be stopped unnecessarily due to erroneous adjustment.

In addition, the rotation speed of the motor 14 can be changed in multiple stages by switching the sub switch 16, or the variable resistor 17 can be changed without providing the sub switch 16.
It is also possible to perform stepless adjustment.

Furthermore, it goes without saying that various oscillation circuits can be used for the configuration of the pulse signal generating section 20 as long as they can generate a predetermined pulse signal. Alternatively, the value of the pulse width τ of the output pulse signal may be kept constant and the pulse rate may be changed.

[Effects of the invention] As described above, the present invention includes the switching section 21 interposed in the energizing circuit of the motor 14, so that the on/off ratio in the switching section 21 can be changed steplessly, so that the average applied to the motor 14 can be adjusted. Voltage V _n
can be changed continuously, so the user can obtain the optimum inner blade drive speed.

Furthermore, since there is no resistive element in series with the motor 14, the rotational speed changes little with respect to load fluctuations, allowing stable shaving operation and minimizing power loss.

Furthermore, while the sub-switch 16 can stop the generation of pulse signals, it remains on when no signal is input to the switching section 21, thereby reducing power consumption as much as possible during high-speed rotation that requires a large amount of power. It has excellent advantages such as being able to suppress

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an outline of the present invention. FIG. 2 is a front view showing an example of implementing the present invention, FIG. 3 is an electric circuit diagram of a control circuit, and FIG. 4 is a waveform diagram illustrating the operating status of the circuit. 14...Motor, 15...Main switch, 16...
...Sub switch, 19...Power supply section, 20...Pulse signal generation section, 21...Switching section.

Claims (1)

[Claims for Utility Model Registration] A motor 14 that drives the inner blade, and a power supply unit 19 that supplies power to the motor 14.
A main switch 15 that regulates the starting timing of the motor 14; A pulse signal generator 20 that can continuously change the ratio τ/T of the pulse width τ per period T; , and a switching section 21 that connects with the input of the signal outputted from the pulse signal generating section 20 to turn on and off the energizing circuit. The above-mentioned pulse signal generating section 20 can stop the signal output by switching the switch 16, while the switching section 21 continues to be in the ON state when the signal input from the pulse signal generating section 20 disappears. The electric shaver according to item 1. The variable range of the output signal in the pulse signal generator 20 is limited to a range within which the motor 14 can stably rotate.
The electric shaver according to item 1 or 2.