JPS6331354Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a voltage non-linear resistance element, and more particularly to an electrode arrangement structure of a voltage non-linear resistance element.

Voltage nonlinear resistance elements are also called varistors.
It has a unique property that the resistance value changes non-linearly depending on the applied voltage, and the resistance value sharply decreases in the range where the applied voltage exceeds the varistor voltage (limiting voltage) of the element. Focusing on these unique properties, voltage nonlinear resistance elements are used to prevent noise in small DC motors related to audio equipment, protect relay contacts, protect semiconductor devices from static electricity, and absorb discharge in color television cathode ray tube circuits. It is widely used as a means of

The present invention relates to a voltage nonlinear resistance element suitable for use in the above-mentioned fields of application, particularly for noise prevention in small DC motors.

In general, small DC motors have small widths of commutator pieces and brushes, the rate of change in armature coil current over time is large, and the reactance voltage becomes large. , sparks occur between the commutator surface and the brush. This spark causes a spark-like noise voltage and also causes wear of the commutator and brushes, which tends to shorten the life of the motor. The above-mentioned noise voltage is a bipolar voltage whose peak value is several tens of times higher than the power supply voltage, and has an adverse effect on audio equipment, so it must be removed.

A voltage non-linear resistance element is used as such a noise prevention means, and absorbs the noise voltage into a short circuit in the range in which it exceeds the varistor voltage.

Next, a small DC motor using a voltage non-linear resistance element and a conventional voltage non-linear resistance element will be explained with reference to FIGS. 1 and 2. FIG. 1 shows a cross-sectional view of a small DC motor equipped with a voltage nonlinear resistance element 1, in which 2 is an armature coil, 3 is a rotating shaft, 4 is a commutator, 5a, 5b are brushes, 6a, 6
b is a magnetic field. The voltage nonlinear resistance element 1 is fitted on the shaft between the armature coil 2 and the commutator 4, and is provided with electrodes connected to the commutator, as will be described later.

FIGS. 2A and 2B show a top view and a bottom view, respectively, of a conventional voltage nonlinear resistance element. This conventional example shows a voltage nonlinear resistance element with an electrode structure corresponding to a commutator 4 having three pieces, and is a disk-shaped sintered body 8 having a mounting hole 7 in the center. Three electrodes 9a, 9b, 9c are equally distributed on _one side of the
Electrodes 9d, 9e, and 9f are formed at positions facing electrodes a, 9b, and 9c, respectively, and electrodes 9a and 9e,
Connect 9b and 9f, 9c and 9d to lead wire 1, respectively.
0a, 10b, 10c, each electrode 9a, 9
Lead wires 10 for connection to the outside are connected to b and 9c, respectively.
d, 10e, and 10f are attached by soldering or the like.

As shown in FIG. 3, this voltage nonlinear resistance element is constructed by connecting the lead wires 10d, 10e, 10f to the commutator pieces 4a, 4b, 4c of the commutator 4, respectively. -9e, 9c-
The varistor layers A, B, and C between 9F are triangularly connected. Note that 2a, 2b, and 2c are armature coils, and in this example, they are shown as having triangular connections, but they may also be connected in a star shape.

As mentioned above, the advantage of having electrodes formed on both sides of the sintered body is that the area of the sintered body that acts as a varistor can be larger than when electrodes are formed only on one side of the sintered body. . However, the conventional device shown in FIG. 2 has a structure in which the electrodes on the front and back surfaces are connected by lead wires 10a, 10b, and 10c, resulting in poor workability and poor production efficiency. Also, external connection lead wires 10d, 10e, 1
In addition to 0f, lead wires 10a, 10 for connecting between electrodes
Because of the presence of wires b and 10c, the number of lead wires increases, the structure becomes complicated, it is not easy to attach to equipment, and the reliability is correspondingly poor.

The present invention eliminates the above-mentioned drawbacks, eliminates the need for lead wires for connection between electrodes, is highly productive, is easy to attach to equipment, and also increases the electrode area and increases the energy withstand capacity. An object of the present invention is to provide a voltage nonlinear resistance element.

In order to achieve the above object, the present invention provides a voltage nonlinear resistance element in which a plurality of electrodes are formed on the front and back surfaces of a sintered body, each separated by a gap, in which the sintered body is oxidized. The sintered body is made of a titanium-based sintered body, has a notch in the periphery of the gap, and a conductive layer formed in the notch connects one of the surface-side electrodes to the surface-side electrode. and a back side electrode facing another adjacent front side electrode are electrically connected to each other via the gap.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The content of the present invention will be specifically described below with reference to the accompanying drawings, which are examples. FIG. 4 is a plan view of the voltage nonlinear resistance element according to the present invention, and FIG. 5 is a perspective view thereof. The voltage nonlinear resistance element shown in this embodiment is also configured to prevent noise in a small three-pole DC motor having three commutator pieces, as described above.

8 is a sintered body formed in an annular shape with a mounting hole 7 in the center. Conventionally, this sintered body 8 is made of silicon carbide (Sic), which obtains varistor properties at the contact surface between particles, or the sintered body itself is a linear resistor, but the electrodes attached to it are Tin oxide (SnO ₂ )-based or iron oxide (Fe ₂ O ₃ )-based materials have been used, but in this invention, the sintered body itself has varistor characteristics. Titanium oxide (TiO ₂ )
It is composed of things related to the system. This is because titanium oxide-based sintered bodies exhibit excellent varistor characteristics in a low voltage range and are most suitable for use in small DC motors.

11a, 11b, 11c are on the surface of the sintered body 8,
The fan-shaped electrodes 11d, 11e, and 11f are arranged at three equal intervals through gaps, respectively, and the electrodes 11a, 1
These are fan-shaped electrodes of the same shape formed on the back surfaces corresponding to 1b and 11c. These electrodes 11
A, 11b, 11c, 11d, 11e, and 11f are formed by a silver alloy paste printing method or the like.
At the outer periphery of the gap located between each electrode,
Notches 12a, 12b, 12c reaching the front and back surfaces
are recessed, and conductive layers 13a, 13b, 1
3c is formed. These conductive layers 13a,
13b and 13c are front and back side electrodes 11c and 11d, 11a and 11e, and 11
b and 11f, each surface electrode 11a, 11b, 11
A portion a formed so as to be in contact with the edges of the notches 13a, 13b, 13c near the outer periphery of c, and a portion a formed on the opposite side of the notches 13a, 13b, 13c near the outer periphery of the back side electrodes 11d, 11e, 11f. They are connected to each other via a portion b formed so as to be in contact with the edge.

On the other hand, between the conductive layers 13a, 13b, 13c and the electrodes 11a, 11b, 11c,
Gaps g ₁ , g ₂ , and g ₃ are formed as non-electrode formation surfaces. Also, the electrodes 11d, 11e, 11 on the back side
A similar gap is also formed between the edge opposite to the edge provided with the protrusion b and the conductive layers 13a, 13b, and 13c.

That is, in this embodiment, the front side electrodes and the back side electrodes 11a and 11e, 11b and 11f, and 11c and 11d each constitute one electrode, and between the electrodes 11a and 11e and the electrodes 11b and 11f, 11b, 11f and electrodes 11c, 11d
and between the electrodes 11c, 11d and the electrode 11a,
11e, there are electrodes 11b and 11c, 11c and 11, which are opposite to each other on the front and back sides.
A varistor layer having a thickness of the sintered body between f and 11a and 11d is obtained.
Therefore, the lead wires 10d, 10 are connected to the electrodes 11a, 11b, 11c or 11d, 11e, 11f.
e and 10f, respectively, and the lead wire 10
When the other ends of d, 10e, and 10f are connected to the commutator pieces 4a, 4b, and 4c of a small DC motor, respectively, as shown in FIG.
The circuit configuration is triangularly connected.

When forming the conductive layers 13a, 13b, 13c in the above-mentioned notches 12a, 12b, 12c, the sixth
As shown in the figure, a front and back electrode is printed and coated on a titanium oxide (TiO ₂ )-based sintered body 8 having a notch, and at the same time, a conductive agent 1 is applied to the tip.
4 attached to the jig 15, each of the notches 12a, 1
2b and 12c, the jig 15
The sintered body 8 can be held down to form a conductive layer, and the electrode forming operation can be performed extremely easily.

In titanium oxide-based voltage nonlinear resistance elements where the sintered body itself exhibits varistor characteristics, the energy withstand capacity depends on the electrode area, and as the electrode area becomes smaller, the energy withstand capacity also decreases and the withstand voltage characteristics etc. decrease. However, in the present invention, as described above, the electrodes on both sides of the sintered body 8 are connected to the notches 12.
Since conduction is made through a, 12b, and 12c to increase the electrode area, the energy withstand capacity is increased and the withstand voltage characteristics are improved.

Moreover, the notches 12a, 12b, 12c are the electrodes 11a, 11b, 11c or 11d, 11
Since the notches 12a, 12b, 12c are formed in the gap separating the electrodes 11a, 11b, 11c or 11f,
The areas of d, 11e, and 11f are not reduced. Therefore, despite the presence of the notches 12a, 12b, and 12c, a voltage nonlinear resistance element with high energy tolerance and excellent withstand voltage characteristics can be obtained.

7 and 8 show a plan view and a perspective view of another embodiment of the voltage nonlinear resistance element according to the present invention. The feature of this embodiment is that cutouts 12'a to 12'a to 12' are formed on the inner circumference of the sintered body 8 formed in an annular shape.
2'c, the conductive layers 13'a to 13'c connecting the front and back electrodes can be connected to the notch 12'a.
It is formed on the surface of ~12'c. It goes without saying that this embodiment also provides excellent effects similar to those shown in FIGS. 4 and 5.

As explained in detail above, the present invention provides a voltage nonlinear resistance element in which a plurality of electrodes are formed on the front and back surfaces of a sintered body, each separated by a gap, in which the sintered body is oxidized. It is composed of a titanium-based annular sintered body, and has a notch in the periphery of the gap in the sintered body, and a conductive layer formed in the notch connects one of the electrodes on the surface side to the surface. Since the side electrode is electrically connected to the back side electrode facing the other adjacent front side electrode through the gap, there is no need for a lead wire for connection between the electrodes, and the conventional front side electrode is not required. This is a highly reliable voltage non-conductor that is easier to install in equipment than the one that connects the back side electrode with a lead wire, and also increases the electrode area as much as possible and increases the energy withstand capacity. A linear resistance element can be provided.
In the present invention, the number of electrodes may be two or more as long as they are formed on each of the front side and the back side. Furthermore, it goes without saying that it can be used not only for small DC motors but also for other devices.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing the schematic structure of a small DC motor equipped with a voltage non-linear resistance element, Figs. 2 A and B are a plan view and a sectional view of a conventional voltage non-linear resistance element, and Fig. 3 The figure shows a circuit diagram of a small DC motor using the voltage nonlinear resistance element shown in Figure 2, and Figure 4.
5 and 5 are a plan view and a perspective view of a voltage nonlinear resistance element according to the present invention, FIG. 6 is a diagram illustrating the manufacturing method thereof, and FIGS. 3A and 3B respectively show a plan view and a perspective view of another example of a linear resistance element. 8... Sintered body, 11a to 11f... Electrode, 12
a to 12c, 12'a to 12'c...notch, 13
a to 13c, 13'a to 13'c... conductive layers.

Claims (1)

[Scope of utility model registration request] In a voltage nonlinear resistance element comprising a plurality of electrodes separated by gaps on the front and back surfaces of a sintered body, the sintered body is made of a titanium oxide based sintered body, and the sintered body is made of a titanium oxide based sintered body, and The body has a cutout in the periphery of the gap, and a conductive layer formed in the cutout allows one of the surface-side electrodes to be connected to the other surface adjacent to the surface-side electrode via the gap. A voltage nonlinear resistance element characterized by electrically connecting an electrode and an electrode on the back side opposite to each other.