JPH0241259B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a chip-type noise absorbing element that can simultaneously remove noise due to abnormal voltage and high frequency voltage.

(Structure of conventional example and its problems) SiC varistors are conventionally known as elements that absorb abnormal voltage. In general, the voltage-current characteristics of this element are approximated by I=(V/C)〓 up to the element whose resistance value changes depending on the applied voltage. Here, I is the current flowing through the varistor, V is the voltage between the varistor element electrodes, α is the voltage nonlinearity index, and C is a constant specific to the element.

Elements with such characteristics include, in addition to SiC, varistors mainly made of ZnO, varistors using silicon single crystal, and varistors using tin oxide.

These varistors exhibit extremely good effects in absorbing noise caused by abnormal voltages.
However, no absorption effect can be obtained for noise caused by abnormal frequency voltages.

Recently, micromotors have been used in audio equipment.
Spark voltage generated in the commutator of a micromotor is one of the causes of noise. As a countermeasure to this problem, SiC varistors have traditionally been used. However, as mentioned above, although it is effective in absorbing abnormal voltage, it cannot sufficiently remove frequency noise in the AM band or FM band, so methods such as connecting a capacitor in parallel between the brushes or inserting a coil etc. have been taken. This method has drawbacks such as an increase in the number of parts and the number of assembly steps required.

(Object of the Invention) The present invention has been made in order to eliminate the drawbacks of the above-mentioned conventional examples, and provides a chip-type noise absorbing element that simultaneously absorbs abnormal voltage and abnormal frequency voltage with a single element. It is.

(Structure of the Invention) In order to achieve the above object, a ceramic dielectric layer and a conductor layer are laminated, a glassy voltage linear resistance layer is provided as the outermost layer, and the ceramic dielectric layer and the conductor layer are formed. Terminal electrodes are provided so that the capacitor element section and the voltage linear resistance element section are connected in parallel.

(Description of Examples) Hereinafter, examples will be described in detail based on the drawings.
FIG. 1 and FIG. 2 each show an embodiment of the present invention. 1 is a ceramic derivative layer,
It is a dielectric material mainly based on barium titanate,
Some have dielectric constants of about 2000 to 100000. In this example, a material with a dielectric constant of 10,000 was used. Note that 1 may be a semiconductor ceramic dielectric layer. 2 is a conductor layer, and in this example, a palladium metal layer was used. Reference numeral 3 is a vitreous voltage-dependent resistance layer made by making a paste of a mixed powder of ZnO and B-Si-Bi-O glass powder with an organic binder, applying the paste, and baking it at a temperature of 800°C. 4 and 5
is a terminal electrode, and in this example, a silver electrode was used. In this example, the voltage between the electrodes 4 and 5 was set to 13 V at a current of 10 mA, and the capacitance at 1 KHz was made to be 0.01 μF.

The device of the present invention having the above configuration is used as a third device.
Wiring was done between the commutators of a 12V motor as shown in the schematic diagram of the motor section in the figure, and the noise electric field strength during operation was measured. In FIG. 3, 6, 7, and 8 are commutators, 9 and 10 are brushes, 11, 12, and 13 are rotor coils, 14, 15, and 16 are elements of the present invention, and 17 and 18 are lead wires.

FIG. 4 is a diagram showing an example of measurement results. A is a case where the element of the present invention is used, B is a case where a conventional SiC varistor is used, and C is a case where no countermeasure is taken. As is clear from FIG. 4, the effect of the device of the present invention is recognized over a wide frequency range.

(Effects of the Invention) As explained above, since the element according to the present invention has both a varistor function and a capacitor function, it can absorb abnormal voltage and abnormal frequency voltage at the same time. In particular, such chip-type noise absorbing elements can be used in a wide range of fields, including application to micromotors in audio equipment and prevention of external noise in microcomputer application equipment in the future. The industrial value is extremely large.

[Brief explanation of drawings]

1 and 2 are cross-sectional views of a chip-type noise absorbing element according to an embodiment of the present invention, and FIG.
FIG. 4, a circuit diagram of a motor to which the same element is applied, is a diagram showing a performance comparison between the conventional element and the element of the present invention. 1... Ceramic dielectric layer, 2... Conductor layer,
3... Voltage-dependent resistance layer, 4, 5... Terminal electrode.

Claims (1)

[Claims] 1 A plurality of ceramic dielectric layers and conductor layers are alternately laminated and sintered, at least one of the outermost layers of the laminate is made of a conductor layer, and zinc oxide is mainly formed on the outermost conductor layer. A vitreous voltage-dependent resistance layer is provided by coating and baking a glass powder paste containing a powder dispersed therein, and a capacitor element portion constituted by the ceramic dielectric layer and the conductive layer and a voltage-dependent resistance layer are provided. A chip-shaped noise absorbing element formed by forming a pair of terminal electrodes that are bonded together by baking so that they are connected in parallel with the resistor element.