JPH09154251A - Vibration motor - Google Patents

Abstract

(57) Abstract: A motor for generating alarm vibration in a small-volume electronic device that consumes less current is provided. A motor having an unbalanced weight and generating an alarm due to unbalanced vibration has a characteristic of 3 or less.
However, it is not possible because the volume is too large. The motor that can be stored in the allowable space has the characteristic of 1, and the speed is too fast and the current becomes large. However, if a constant voltage circuit that limits speed fluctuations due to the characteristics of the battery and the characteristics of the motor itself is added to the motor of characteristic 1, characteristic 4b is obtained, and a vibrating motor that produces constant unbalanced vibration and consumes less current is obtained. To be

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration motor housed in a device such as a pager for issuing an alarm.

[0002]

2. Description of the Related Art Conventionally, there has been a system for receiving a ringing signal from a specific caller with a pager and issuing an alarm sound to inform the user. However, in the above system, the alarm sound is also emitted to the surroundings, which may cause discomfort to people nearby.

Therefore, a device has been proposed in which the device itself is vibrated without emitting an alarm sound, and only the wearer is directly notified of the alarm by the vibration. As shown in FIG. 6, the structure accommodates a motor 15 having an eccentric weight 17 attached to a shaft 16 and vibrates the entire apparatus by vibration generated by unbalanced rotation of the motor. The configuration at that time is as shown in FIG.

[0004]

However, the motor used for such an application has a small power generation constant due to size restrictions. Further, since a small battery which is limited for portable use is used, a motor with high current efficiency is required, and a coreless type motor is generally selected as a low voltage / high efficiency motor. In such a coreless motor, the no-load rotation speed becomes 10,000 to tens of thousands rpm, the PV value of the bearing increases due to imbalance, the bearing loss increases, and the sliding resistance between the brush and the commutator increases. Sliding loss also increases. Therefore, as a result, the motor current increases.

To solve these problems, the voltage applied to the motor may be lowered for use, but the starting torque is lowered and the unbalanced load cannot be driven.

An object of the present invention is to solve the above-mentioned conventional problems in a drive mechanism and to provide an inexpensive and easily housed vibration motor.

[0007]

In order to achieve this object, the vibration motor of the present invention has an unbalanced weight for generating vibrations and a constant speed limit for limiting the speed fluctuation due to the characteristics of the battery and the characteristics of the motor itself. It has a voltage circuit.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram showing the rotational speed-torque characteristic of the system of the present invention. 1 is the rotation speed-torque characteristic of the motor when driven by a battery voltage, for example 3V, 2 is when the applied voltage is lowered to lower the current value due to sliding loss between the brush and the commutator (for example 0.8V) Number-torque characteristics of the motor of 3
3 is a rotation speed-torque characteristic of the motor when the rotation speed at the operating point A is maintained.

FIG. 2 is a characteristic diagram showing the applied voltage-rotational speed characteristic and the applied voltage-current characteristic of the system of the present invention. Reference numeral 4 is a rotation speed characteristic when the constant voltage circuit of the system of the present invention is not attached, and 4b is a rotation speed characteristic when the constant voltage circuit is attached. 5 is a current characteristic when the constant voltage circuit of the system of the present invention is not attached, and 5b is a current characteristic when the constant voltage circuit is attached.

FIG. 3 is a block diagram of the system configuration of the present invention. 6 is a battery, and 7 is a constant voltage circuit for keeping the voltage applied to the motor 8 constant.

In order to generate vibrations in a small-volume electronic device such as a pager, a motor having a rotation speed-torque characteristic shown in FIG. 1 is desirable, but a motor having such a characteristic becomes large in size. With the allowable dimensions, only a motor having the rotational speed-torque characteristic of 1 in FIG. 1 can be produced. However, with the characteristic of 1, the rotation speed of the motor becomes too high and the load loss (particularly the sliding loss between the brush and the commutator) becomes large,
As a result, the current value increases. On the other hand, if the applied voltage of the motor is lowered so as to pass the operating point A by the current value and the characteristics shown in FIG. Can't do it.

However, if the constant voltage circuit 7 is added to the characteristic of FIG. 1 to form the system of FIG. 3 and the characteristic of 4b of FIG. 2 is achieved, the above-mentioned problems can be solved.

FIG. 4 shows a specific example thereof. Reference numeral 6 is a battery, 8 is a motor, and the constant voltage circuit 7 is composed of a transistor 9, a Zener diode 10, and a resistor 11. That is, the base of the transistor 9 whose collector is connected to the positive electrode of the battery 6 is connected to the positive electrode of the battery 6 via the resistor 11 and the Zener diode 10, and the emitter is connected to the positive electrode of the battery 6 via the motor 8. It is connected to the negative electrode.

According to this structure, when the motor is rotating steadily, unbalanced driving is performed in the low rotation region, so that sliding loss between the brush and the commutator is reduced. On the other hand, when the battery voltage is high, the motor current increases, and the rotation speed tends to increase, the transistor 9 acts to absorb the voltage of the battery 6. As a result, the motor 8 can be unbalancedly driven in a predetermined rotation range.

As described above, according to this embodiment, by providing the constant voltage circuit 7, the motor can be driven without impairing its performance. The present embodiment can also be applied to a brushless motor.

[0017]

As described above, the vibration motor of the present invention is provided with an unbalance weight for generating a vibration which is a silent alarm, and a constant voltage circuit for limiting the speed fluctuation due to the characteristics of the battery and the characteristics of the motor itself. A vibration motor that consumes less current can be realized by providing and controlling so as to generate a constant unbalanced vibration.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a motor according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram of a motor according to an embodiment of the present invention.

FIG. 3 is a block diagram of a motor according to an embodiment of the present invention.

FIG. 4 is a specific circuit diagram according to an embodiment of the present invention.

FIG. 5 is a block diagram of a conventional vibration motor drive.

FIG. 6 is a block diagram of a vibration motor alone.

[Explanation of symbols]

 6,13 Battery 7 Constant voltage circuit 8,14 Motor 9 Transistor 10 Schener diode 11 Resistance

Claims (1)

[Claims] 1. An unbalanced weight for generating a vibration, which is a silent alarm, in a small-volume electronic device, and a constant voltage circuit for limiting fluctuations due to the characteristics of the battery and the characteristics of the motor itself. Vibration motor controlled to generate unbalanced vibrations by a number.