JPH064519Y2 - Fuse - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to an improvement of a fuse used in household electronic and electric products.

<Prior Art and Problems> Conventionally, when an electric device is used for a predetermined long time (for example, 1000 hours), the electric device is automatically disconnected from a power source, which is a so-called time indicator. A sublimation material is provided and a contact is opened when the sublimation material disappears, and a ventilation hole that is opened and closed by a solenoid valve is provided in the closed container, and the solenoid valve is opened by energizing the electric device. It is known that the sublimation material disappears to open the contact when the time reaches the predetermined long time.

By the way, in electronic / electrical equipment products, energization and heat generation are unavoidable during its use, and fatigue progresses with the lapse of time due to the accumulated heat generated over time. If the electric product is managed and repaired or replaced before destroying the product, explosion or fire accident at the time of destruction can be prevented, which is advantageous for safety and security.

Therefore, even if the energization time is the same, if the magnitude of the load, and thus the energization current value, is different, the fatigue level based on the cumulative accumulation of the above-mentioned heat generated by the equipment is different. It is difficult to control the safety of products from the degree of fatigue.

<Purpose of the Invention> An object of the present invention is to provide a fuse capable of easily managing the safety of electronic and electric equipment products used at home from the fatigue level based on the accumulated heat of the equipment over time. .

<Means for Solving the Problems> A fuse of the present invention receives heat generated by a heat generating element, a switch element, and the heat generating element which generates heat by passing a current,
It is characterized by comprising an element for activating the switch element when the product of the generated heat and the usage time reaches a predetermined value.

<Description of Embodiments> The present invention will be described below with reference to the drawings.

In the figure, reference numeral 1 is a metal case having a predetermined resistance value, and a lead conductor wire 2 is connected to one end thereof. 3 is a sublimable insulating pellet, 41 is a first spring, and 5 is a movable contact member, which is slidably contacted with the inner surface of the case. 6
Is a fixed contact rod and 7 is a bushing through which the fixed contact rod is provided. The bushing is fixed to the other end of the case by caulking the other end, and in particular, is not subjected to a sealing treatment and has air permeability. 42 is a second spring.

This fuse is used by connecting it in series to electronic / electrical equipment, and its installation location is arbitrary.

The fuse of the present invention is a cumulative value of the product of the squared value of the current I supplied to the electronic / electrical device and its supply time T, that is, ∫ ₀ ^T I ²
It activates when dt reaches a predetermined value and shuts off the power supply to the equipment.

In the figure, the current flows in the route of fixed contact rod 6 → movable contact member 5 → case 1 → lead conductor 2. The current value is the same as I above, and if the resistance of the case is R, heat W of ∫RI ² dt is generated. It is assumed that a sublimable substance is used for the insulating pellet, the volume is reduced by receiving heat, and the length is reduced by ΔL by the unit heat amount.

Now, when the power to the electronic / electrical devices should be cut off∫
_{When 0} ^T I ² dt is K, the heat transfer rate of heat generated from the case to the pellet is a (o <a <1), and when the first spring extends by the length L, the spring stress of the first spring is If it is smaller than the spring stress of the two springs (at this time, the movable contact material is detached from the fixed contact rod), the requirement for cutting off the electric current is ΔLa∫ ₀ ^T RI ² dt = L−. .

Therefore, And By setting L, ΔL, a or R so as to satisfy the above condition, when the product of the squared value I ² of the energizing current to the electronic / electrical device and the operating time T reaches a predetermined value K, In the above to the device, the pellet, which does not substantially rise at room temperature, sublimates by heating when the device is used, the sublimation point is a sublimable substance at room temperature or higher, for example, gallium chloride, organic In addition to P-quinone, substances that sublime at room temperature, for example, granules such as shoots, are surrounded by a sustained release material (usually a resin such as nylon) and are substantially heated at a desired temperature. Microcapsules designed to be sublimated can be used.

∫ ₀ ^T I ² dt in the equipment is the cumulative value of the amount of heat received by the equipment and indicates the degree of fatigue of the equipment. Therefore ∫ I ² dt
Is empirically set to a predetermined value according to the heat resistance of the electronic / electrical equipment, and when the predetermined value is reached, the fuse of the present invention is activated to shut off the power to the equipment and inspect the equipment. By replacing the fuse and reusing the device, damage to the device can be prevented. The value of K must be set smaller as the replacement of the fuse progresses. Therefore, L, ΔL, a or R of the fuse is adjusted so as to enable such setting.

In the above fuse, the metal case 1 having a predetermined resistance value functions as a heat generating element that generates heat due to an applied current, and the sublimable insulating pellet 3 receives the heat generated by the heat generating element, and the generated heat and the operating time Of the movable contact material and the fixed contact rod function as a switch element, and the first spring and the second spring transmit the response of the response element to the switch element. It functions as a transmission element.

<Effects of the Invention> According to the fuse of the present invention, as described above,
When the electric equipment reaches a certain degree of fatigue, the electric power to the equipment can be cut off, so that the equipment can be inspected and continued to be used, and the equipment can be prevented from bursting, fire, or the like.

[Brief description of drawings]

The drawing is an illustration showing a fuse according to the present invention. In the figure, 3 is an element, and 5 and 6 are switching elements.

Claims (1)

[Scope of utility model registration request] 1. A heat generating element that generates heat by an energizing current, a switch element, and heat generated by the heat generating element, and the switch element is activated when the product of the heat generated and the operating time reaches a predetermined value. A fuse comprising an element.