JP3079760B2 - Cased capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cased capacitor having an explosion-proof valve.

[0002]

2. Description of the Related Art Capacitors in a case, such as an aluminum electrolytic capacitor, employ various technologies in order to prevent an explosion when an overvoltage is applied or an abnormal voltage is generated by applying a reverse voltage. doing. For example, a current fuse or a thermal fuse is arranged inside or outside the case, and the fuse is connected in series with the capacitor element. The fuse is cut off when an overvoltage is applied, and the capacitor is disconnected from the circuit. Further, an explosion-proof valve is provided on the case or the lid in order to prevent the capacitor from exploding due to the gas filled in the case.

[0003]

However, the capacitor provided with the explosion-proof valve has a disadvantage that the fuse operates after the explosion-proof valve is activated when the voltage is applied slowly. If the explosion-proof valve is operated first, the gas inside the case is exhausted, and the electrolytic solution impregnated in the capacitor element is scattered, which may damage other electronic parts of the device incorporating the capacitor.

An object of the present invention is to improve the above-mentioned drawbacks and to provide a cased capacitor capable of preventing the explosion-proof valve from operating and damaging other electronic components.

[0005]

According to the present invention, in order to achieve the above object, an explosion-proof valve is provided in a case-containing capacitor in which a capacitor element is housed in a case provided with an explosion-proof valve, terminals are drawn out and hermetically sealed . Position in contact with the case surface
With a step to decide, and away from the explosion-proof valve
It is an object of the present invention to provide a cased capacitor characterized by providing an insulating cap covering a case and having a contact switch provided in the vicinity, and connecting the capacitor element and the contact switch in parallel.

In order to connect the capacitor element and the contact switch in parallel, these terminals are directly connected to each other, or are connected by an external circuit or the like.

[0007]

When an overvoltage or the like is applied to a capacitor such as an aluminum electrolytic capacitor, the electrolytic solution is gasified by the heat generated by the capacitor element. The pressure of this gas causes the explosion-proof valve provided in the case to expand. When the explosion-proof valve expands, the pressure activates a contact switch located near the explosion-proof valve. When the contact switch is operated, the current flowing through the capacitor element flows toward the contact switch because the contact switch is connected in parallel with the capacitor element. Therefore, an increase in gas pressure is suppressed, and the operation of the explosion-proof valve can be prevented.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.
1A and 1B, reference numeral 1 denotes a case made of aluminum or the like, and a thin-walled explosion-proof valve 3 is provided on a bottom surface 2. 4
Is a capacitor element housed in the case 1, which is obtained by laminating an aluminum anode foil and a cathode foil with a separator interposed therebetween, and impregnated with an electrolytic solution. Reference numeral 5 denotes a lid attached to the opening 6 of the case 1 and has terminals 7 and 8. The capacitor element 4 is connected to the terminals 7 and 8. Reference numeral 9 denotes an insulating cap made of an insulating resin that covers the case 1 from the bottom surface 2 side. And this insulation
The step 9 ′ formed on the inner surface of the cap 9
Place the end of the bottom surface 2 provided with the explosion-proof valve 3 and position the case 1
Decide. Reference numeral 10 denotes a contact switch provided on the insulating cap 9, and its contacts 11 and 12 are connected to the explosion-proof valve 3 by a step.
The terminals 13 and 14 are pulled out from the edge 15 in the vicinity of a distance determined by the portion 9 ′ . When the cased capacitor 16 is connected to an external circuit, the terminals 7 and 8 provided on the lid 5 and the terminals 13 and 14 of the contact switch 10 are connected as shown in FIG. And the contact switch 10 is connected in parallel. Note that, apart from the external circuit, the terminals 7 and 8 may be connected to the terminals 13 and 14 by lead wires or the like in advance.

In the above embodiment, when an overvoltage is applied to the capacitor 16 and gas is generated, the internal pressure of the case 1 increases. In addition, as shown in FIG. 3A, the explosion-proof valve 3 expands and hits one contact 11 of the contact switch 10 and moves it toward the other contact 12. Before the explosion-proof valve 3 is broken, as shown in FIG.
Contact This prevents the capacitor element 4 from being short-circuited by the contact switch 10 and preventing the explosion-proof valve 3 from operating due to an increase in gas pressure. Also, the case 1 is located on the step 9 '.
Therefore, since it is positioned, the capacitor 16 vibrates.
Is added, the explosion-proof valve 3 and the contact switch 1
The distance to 0 does not change. Therefore, explosion-proof valve 3
Before swelling to a predetermined value due to an increase in pressure in case 1,
Contact 11 is not pushed by the explosion-proof valve 3
The switch 10 can be prevented from malfunctioning.

Next, an overvoltage application test was performed on the above embodiment and the conventional example, and the operation status of the explosion-proof valve was examined. As samples, 10 aluminum electrolytic capacitors rated 200 V-680 μF are used. The conventional example has the same structure except that the insulating cap is removed in the above embodiment. The test conditions were applied voltage DC300V, current 7AMAX, and ambient temperature at room temperature. As a result of the test, explosion-proof valves did not operate in all of the examples. Then, the fuse incorporated in the test circuit was blown. On the other hand, in all the conventional examples, the explosion-proof valves were operated.

FIG. 4 shows another embodiment of the present invention.
In this embodiment, in particular, the explosion-proof valve 17 is provided on the side surface of the case 18. The contact switch 19 is connected to the contact 20
And 21 are disposed in the insulating cap 22 in the vicinity of the explosion-proof valve 17, and the terminals 23 and 24 are pulled out from the rim 25 so as to approach each other. Also in the case of the cased capacitor 26 of this embodiment, when connecting to an external circuit, the terminals 28 and 29 provided on the lid 27 and the terminals 23 and 24 of the contact switch 19 are connected respectively, and The contact switch 19 is connected. Therefore,
When the explosion-proof valve 17 expands due to an increase in the gas pressure in the case 18 and the contact 20 contacts the contact 21, the capacitor element 30 is short-circuited by the contact switch 19.
Due to the short circuit, the operation of the explosion-proof valve 17 is prevented.

FIG. 5 shows another embodiment of the present invention. In this embodiment, as the capacitor element 31,
A structure in which the cathode foil 32 protrudes from the bottom surface is used.
Then, the capacitor element 31 is attached to the case 33 by the cathode foil 3.
The two parts are stored in contact with the bottom surface 34 of the case 33. The contact 36 of the contact switch 35 is one, and this
3 is disposed near the explosion-proof valve 37 provided on the bottom surface 34. Only one terminal 38 of the contact switch 35 is pulled out from the edge 40 of the insulating cap 39. In this embodiment, the explosion-proof valve 3
7 substantially serves as another contact of the contact switch 35. Therefore, when connecting the case-containing capacitor 41 to an external circuit, only the terminal 43 of the anode provided on the lid 42 needs to be connected to the terminal 38 of the contact switch 35. In this case, when the explosion-proof valve 37 contacts the swelling contact 36, the capacitor element 31 is short-circuited by the contact switch 35 because the cathode foil 32 is in contact with the bottom surface 34 of the case 33.

[0013]

As described above, according to the present invention, the insulating cap having the contact switch is put on the case, the contact switch is arranged near the explosion-proof valve provided on the case, and connected in parallel with the capacitor element. The use of a contact switch can prevent the operation of the explosion-proof valve.
A capacitor in a case that can prevent other electronic components from being damaged can be obtained. Further, according to the present invention, an insulating capacitor is provided.
A step is formed on the inner surface of the case, and the case is
Position the case by touching the surface on which the valve is
Since the switch is located near the explosion-proof valve,
Contact switch malfunctions even if vibration is applied to the capacitor
A highly reliable cased capacitor
Can be If a current fuse is connected to the external circuit in series with the capacitor, the current fuse can be blown by the short-circuit current flowing through the contact switch when the contact switch is activated, and the other current can be blown by the overcurrent. A capacitor in a case that can prevent the parts from being damaged can be obtained.

[Brief description of the drawings]

FIG. 1 shows a front sectional view and a plan view of an embodiment of the present invention.

FIG. 2 shows a circuit diagram incorporating an embodiment of the present invention into a circuit.

FIG. 3 is a front sectional view showing an operation state of the explosion-proof valve according to the embodiment of the present invention.

FIG. 4 shows a front sectional view of another embodiment of the present invention.

FIG. 5 shows a front sectional view of another embodiment of the present invention.

[Explanation of symbols]

1, 18, 33 ... case, 3, 17, 37 ... explosion-proof valve,
4, 30, 31 ... capacitor element, 7, 8, 28, 2
9, 43 ... terminal, 9, 22, 39 ... insulating cap,
10, 19, 35 ... contact switch, 16, 26, 41 ...
Cased capacitor.

Claims (1)

(57) [Claims] 1. A capacitor in a case in which a capacitor element is housed in a case provided with an explosion-proof valve, terminals are drawn out and hermetically sealed, and the capacitor is positioned in contact with a surface of the case provided with the explosion-proof valve.
And a step away from the explosion-proof valve.
A capacitor in a case, comprising: an insulating cap covering a case, having a contact switch provided beside the capacitor, and connecting the capacitor element and the contact switch in parallel.