JPS6014598A - Speaker - Google Patents

Abstract

PURPOSE:To enable free setting of allowable input power value by providing a voice coil temperature detector that outputs an electric signal according to the heat, sensing heat due to temperature rise of a voice coil. CONSTITUTION:When input is applied to a speaker 14, a voice coil generates heat to raise temperature. With the rise of temperature, output voltage of a pyroelectric type infrared sensor 16, a noncontact sensor, is increased, and output amplified by an amplifier 17 is inputted to a comparator 18. This signal is compared with the level of reference signal set arbitrarily by an upper limit temperature setting circuit 19. When the signal from the amplifier 17 becomes larger than the signal from the upper limit temperature setting curcuit 19, a cut off circuit 20 operates to cut off input from an audio amplifier 13 to the speaker 14. Thus, by noncontact detection which is characteristics of the pyroelectric type infrared sensor 16, temperature of the voice coil 9 can be measured directly, and allowable input electric power value can be selected freely by setting to the upper limit temperature setting curcuit 19.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a speaker used in general audio equipment.

The structure of the conventional example and its problems As shown in Figs. A magnetic circuit (5) constructed by incorporating a shaped upper plate (4) is connected to a frame (6), and a gasket (7) and a diaphragm (8) are attached to the periphery of the frame (6). are connected by adhesive etc., and a voice coil (
9), the middle part of this voice coil (9) is held by a damper 00, the lower part of the voice coil (9) is fitted into the magnetic gap aυ of the magnetic circuit (5) without eccentricity, and the diaphragm ( 8) is constructed by pasting one dust cap and four dust caps on the upper surface of the central part. In such a speaker, if excessive input is applied, the temperature of the voice coil will rise abnormally, and the adhesive that adheres the coil to the coil bobbin will soften, causing the coil to come loose, producing abnormal noise. Failures such as short circuits or disconnections may occur due to carbonization of the coil's insulation coating.

Conventionally, bimetals have been used to protect speakers by detecting increases in the temperature of the voice coil. This takes advantage of the fact that the temperature rise is proportional to the square of the current, and as shown in Figure 3, the detection detects the sudden flow of current from the audio amplifier 03 to the voice coil (9) of the speaker α-Yuu. A bimetal was used as a device to indirectly detect the temperature rise of the voice coil (9) of the speaker 0, thereby protecting the speaker.

However, in the conventional speaker 04 using such a bimetal a5, due to the characteristics of the bimetal element,
There was a problem in that it was not possible to arbitrarily set the allowable power value for the same two elements.

OBJECT OF THE INVENTION The present invention solves the above-mentioned drawbacks of the conventional art.
The purpose of the present invention is to provide a speaker whose power value can be arbitrarily set.

Structure of the Invention In order to achieve the above object, the speaker of the present invention is equipped with a voice coil temperature detection device that senses the temperature of the voice coil and the heat caused by the rise, and outputs an electric signal in response to the temperature.
It is composed of

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

FIG. 4 is a configuration diagram of a speaker and its excessive input prevention circuit in Embodiment 1 of the present invention, and FIG.
Components that are the same as those shown here are given the same reference numerals and their explanations will be omitted. In FIG. 4, QQ is an amorphous infrared sensor, 07 is an amplifier, ■ is a comparator, a field is an upper limit temperature setting circuit, (1) is a cutoff circuit, and the pyroelectric infrared sensor aG is , Speaker α◆'s Uremu (6)
A voice coil (9) is installed between the damper OQ and the damper OQ so as to face the voice coil (9). This pyroelectric infrared sensor αQ is for detecting heat due to a rise in temperature of the voice coil (9) to prevent speaker failure.

The next operation will be explained. When input is applied to the speaker 04, the voice coil (9) generates heat and its temperature rises.

Along with that, the pyroelectric infrared sensor α is a non-contact sensor.
The output voltage of G increases, and the output amplified by amplifier Oη is input to the comparator). This signal is compared with the level of a reference signal arbitrarily set in the L limit temperature setting circuit Qll, and if the signal from the amplifier trunk is larger than the signal from the upper limit temperature setting circuit Qll, the disconnection circuit is in good condition. The input from the audio amplifier a to the speaker a is cut off.

In this way, the non-contact detection that is a feature of the pyroelectric infrared sensor Qf9 allows the temperature of the voice coil (9) to be directly measured, and the allowable input power value can be arbitrarily set by setting the upper limit temperature setting circuit 4. In addition, the response speed of the pyroelectric infrared sensor σQ is 40 m5 ec, whereas the response speed of the conventionally used bimetal is 5 to 6 sec.
c, and the audio amplifier 03 and speaker α4 can be separated much faster than when bimetal is used. This prevents the insulation coating of the voice coil (9) from softening, carbonizing, peeling off, short circuits, and coil bobbin. It is possible to reliably prevent the coil from coming off due to softening of the adhesive bonding the coil and carbonization.

In addition, instead of the pyroelectric infrared sensor ae, the temperature change I
Therefore, a passive element or an active element whose resistance value or capacitance value changes may be used.

DETAILED DESCRIPTION OF THE INVENTION Thus, the present invention 1 is provided with a voice coil temperature detection device that senses the temperature of the voice coil and the heat caused by the rise and outputs an electric signal in accordance with the temperature, so that the allowable input power is reduced. The value can be arbitrarily set, and its industrial value is extremely limited.

[Brief explanation of drawings]

Figure 1 is a front view of a conventional speaker, Figure 2 is a cross-sectional view of the same,
Figure 8 is a configuration diagram of a conventional speaker excessive input prevention device.
FIG. 4 is a configuration diagram of a speaker and its excessive input prevention circuit in one embodiment of the present invention. (9)...Voice coil, OQ...Pyroelectric infrared sensor (voice coil temperature detection device). Agent Yoshihiro Morimoto Figure 1 Figure 2 Figure 2

Claims (1)

[Claims] 1. A speaker equipped with a voice coil temperature detection device that senses heat caused by a temperature rise in the voice coil and outputs an electric signal in accordance with the detected heat. 2. The speaker according to claim 1, wherein the voice coil temperature detection device uses a passive element whose resistance value changes with temperature changes. 8. The speaker according to claim 1, wherein the voice coil temperature detection device uses an active element whose resistance value changes with temperature change. -4. The speaker according to claim 1, wherein the voice coil temperature detection device uses a passive element whose capacitance value changes due to temperature change. 6. The speaker according to claim 1, wherein the voice coil temperature detection device is configured to use an active element whose capacitance value changes with temperature changes. 6. The speaker according to claim 1, wherein a pyroelectric infrared sensor is used as the voice coil temperature detection device.