JP4069219B2 - Fuse with sensor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuse with a sensor of a plug type mainly used for automobiles, and a sensor for detecting a current flowing in a fuse blown portion and a fuse by punching a long fuse material made of a single conductive plate. Are integrally formed.
[0002]
[Prior art]
Conventionally, as a general fuse mounted on a fuse box for an automobile, there is a blade type fuse disclosed in US Pat. No. 4,032,264.
[0003]
As shown in FIG. 4, as shown in FIG. 4, a long fuse material 8 in which a thin portion 7 having a constant width is formed in the central portion in the longitudinal direction is sequentially punched into a predetermined shape by pressing. The upper half portion including the thin fused portion 1 of the fuse element 4 formed by forming the thin fused portion 1 having a predetermined width corresponding to the current carrying capacity simultaneously with the pair of left and right conductive terminals 2 and cut to a predetermined length is heat resistant. -It is held by an insulating housing 5.
[0004]
Many of the conventional blade-type fuses are used in the electric system of automobiles, but in many cases slow blow characteristics (the fuse does not blow out due to instantaneous overcurrent, and if the overcurrent continues for a certain period of time, In other words, it has a function to prevent a danger by fusing when there is a danger such as a fire if an overcurrent continues.
[0005]
For this reason, the fuse blows at the time of a dead short, but the fuse does not blow in a continuous short that is so small that the fuse does not blow or a continuous short of a short time (hereinafter referred to as “rare short”). If this condition persists, a vehicle fire may occur.
[0006]
As means for solving this situation, there has been proposed a fire prevention device for an electric system of an automobile disclosed in Japanese Patent Application Laid-Open No. 60-203551.
[0007]
In the fire prevention device disclosed in Japanese Patent Laid-Open No. 60-203551, a current sensor and a circuit breaker are provided between a battery and a fuse provided in an electric wire connecting each electrical component, and the current sensor An excess current signal as a result of comparing the electric wire current signal from the load current signal from each electrical component operation detection circuit with a comparison circuit is sent to the circuit breaker as an abnormal pulse through the monostable multivibrator, It cuts off and protects the electrical components from being energized.
[0008]
[Problems to be solved by the invention]
However, since the conventional fire prevention device is a system in which a current sensor is installed in the middle of the circuit, it is necessary to secure an installation space for the sensor. However, securing the installation space in recent vehicles has become difficult year by year, and there are cases where the installation location is limited or cannot be installed.
[0009]
Further, as a current sensor provided in the middle of the circuit, Japanese Patent Laid-Open No. 60-203551 discloses a system using a Hall element as an example. However, this Hall element is expensive and is called for cost reduction. However, it is difficult to use.
[0010]
Furthermore, devices that detect current without contact, such as Hall elements, are generally susceptible to noise (such as magnetic noise) present in the vehicle, so it is difficult to obtain true value, and it is necessary to take measures against noise. In addition, in the case of a sensor that is directly connected (connected in series with the circuit), at least two new connection points are required, and a voltage drop due to an increase in contact points or poor contact, or heat generation due to this voltage drop. At present, there are various problems such as occurrence.
[0011]
[Means for Solving the Problems]
In the present invention, the fuse element can be used also as a shunt (sensor) for detecting electric current, and the fuse and the sensor are integrally formed by punching from one conductive plate, and the upper half of the element is formed. A thin male with a voltage drop in the thin fused part of the element (hereinafter referred to as “fused part”) integrated inside the lower half of the conductive terminal of the element. It can be detected by a terminal (hereinafter referred to as “detection terminal”).
[0012]
That is, the present invention relates to the top of the fuse element 4 in which the upper half of the pair of left and right conductive terminals 2 and 2 arranged on the same plane is connected to the conductive state by the fusing part 1 corresponding to the current carrying capacity of the fuse. In the plug-in type fuse whose half is held in the heat-resistant / insulating housing 5, the fusing part is formed in a thin shape with the same thickness as the fusing part 1 inside the lower half part of the pair of left and right conductive terminals 2, 2. Detection terminals 3 and 3 for detecting a current of 1 are formed in parallel and integrally with the conductive terminals 2 and 2 ;
The detection terminals 3, 3 are flush with the conductive terminals 2, 2 on the one surface side, and are separated from each other at portions inserted into the female terminals 14, 15. It is a fuse with a sensor.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an exploded perspective view of a fuse 9 with a sensor according to the present invention. The fuse 9 with a sensor is a long fuse material made of a single conductive plate made of zinc (Zn) alloy as shown in FIG. A thin-walled portion 7 having a constant width is formed by cutting along the longitudinal direction at the center of 8 and a pair of left and right conductive terminals 2 and 2 as shown in FIG. The fusing part 1 corresponding to the current carrying capacity of the fuse is connected to the upper half between the detection terminals 3 and 3 and the conductive terminals 2 and 2 are integrally connected to the inner side of the lower half of the conductive terminals 2 and 2. A fuse element with sensor (hereinafter referred to as “element”) 4a is formed by punching, and a flat housing 5 made of transparent resin having heat resistance and insulation is inserted and fixed in the upper half of the element 4a. Is.
[0014]
A fuse 9 with a sensor according to the present invention includes a female female terminal 14 and 14 for insertion of a pair of left and right conductive terminals 2 and 2 provided on a terminal block 13 indicated by a two-dot chain line in the lower part of FIG. The pair of left and right detection terminals 3, 3 are inserted into signal detection female terminals 15, 15.
[0015]
FIG. 6 shows an electric circuit of an automobile using a sensor-equipped fuse 9 according to the present invention, in which a relay 11 is installed immediately after a battery 10, and a fuse with a sensor corresponding to each load A, B, C on the downstream side. 9a, 9b, 9c are arranged in parallel, and the female terminals for fuse 14, 14 are respectively connected to the relay 11 side arranged on the battery 10 side and the loads A, B, C side, and the signal detecting female The terminals 15 and 15 are connected to a determination unit 12 connected to the relay 11.
[0016]
In the case of this circuit, if a dead short occurs between the sensor-equipped fuses 9a, 9b, 9c and any one of the loads A, B, C, the fusing part 1 of the element 4a becomes the same as in the conventional fuse. Only the circuit is cut off by fusing.
[0017]
In the sensor-equipped fuse 9, a signal is always output from the detection terminals 3 and 3 with respect to the current flowing through the fusing part 1 of the element 4 a, and the signal is always input to the determination part 12.
[0018]
Therefore, when an abnormality such as a short circuit is determined between the fuses 9a, 9b, 9c with sensors and the loads A, B, C, an abnormality signal (relay ON signal) is output to the determination unit 12, and the battery The relay 11 installed immediately after 10 is turned off (OFF), and the entire circuit is cut off.
[0019]
FIG. 7 shows a circuit in which fuses 9a, 9b and 9c with sensors and relays 11a, 11b and 11c are arranged in parallel corresponding to the loads A, B and C, respectively. In this case, if a dead short occurs between each of the fuses 9a, 9b, 9c and each of the loads A, B, C, the fuse 9 with the sensor is installed as in the conventional fuse. When a short circuit occurs, only the circuit in which an abnormality has occurred can be blocked when a short circuit occurs.
[0020]
[Action]
In the present invention, as in the case of a conventional fuse, in the case of a dead short, the fusing part 1 of the element is blown, and in the case of a rare short, the fusing part 1 of the element functions as a current detection shunt (sensor). Can be output at the detection terminals 3 and 3 provided integrally with the conductive terminals 2 and 2 of the element.
[0021]
As specified in JASO D612, the fuse is specified to be blown at a constant current and within a fixed time. Normally, the standard width is also determined and managed, and the distribution of the resistance value is a normal distribution as shown in FIG. 5, and the resistance variation in a general shunt depends on the class. ± 0.1 to 1.0%, and the resistance variation in the fuse is ± 3%, which is large compared to the shunt, but the judgment level of abnormal current should be at most ± 1A. This element can be sufficiently used as a shunt.
[0022]
【The invention's effect】
According to the present invention, a compact fuse with a sensor can be provided by combining a fuse function and a sensor function in one element.
[0023]
Furthermore, since the element (melting part) that originally functions as a fuse can be used as a shunt (sensor) for current detection, no special current sensor is required.
[0024]
In addition, according to the present invention, since the detection terminal is provided in the space where the conventional fuse is vacant (inside the lower half of the conductive terminal), the element can be formed within the external dimensions of the conventional fuse. There is no waste in material removal, and it can be handled within the conventional fuse mounting space, and no special space is required.
[0025]
Furthermore, since the conventional fuse function is also provided, the circuit can be protected by a conventional method even in the case of a relay failure (short circuit failure).
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of a sensor-equipped fuse according to the present invention.
FIG. 2 is a partial perspective view of a long fuse material according to the present invention.
FIG. 3 is a front view showing material removal of a conventional blade type fuse.
FIG. 4 is an exploded perspective view of a conventional blade-type fuse.
FIG. 5 is a distribution diagram of resistance values of fuses.
FIG. 6 is an example of an electric circuit of an automobile using a sensor-equipped fuse according to the present invention.
FIG. 7 shows another example of an electric circuit of an automobile using the fuse with sensor according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Thin fused part 2 Conductive terminal 3 Thin male terminal 4 Fuse element 4a Fuse element with sensor 5 Housing 7 Thin part 8 Long fuse material 9 Fuse with sensor 10 Battery 11 Relay 12 Judgment part 13 Terminal block 14 Female for fuse Terminal 15 Female terminal for signal detection

Claims (1)

The upper half of the fuse element 4 connected in a conductive state between the upper half of the pair of left and right conductive terminals 2, 2 arranged on the same plane by the thin fused portion 1 corresponding to the current carrying capacity of the fuse is heat resistant. -In the plug-in fuse held in the insulating housing 5,
The detection terminals 3 and 3 for detecting the current of the fusing part 1 are formed on the inner side of the lower half of the pair of left and right conductive terminals 2 and 2, and detect the current of the fusing part 1. It is formed in parallel and integrally ,
The detection terminals 3, 3 are flush with the conductive terminals 2, 2 on the one surface side, and are separated from each other at portions inserted into the female terminals 14, 15. A fuse with a sensor to perform.

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