JPH0616879U - Current detector - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention aims at facilitating the incorporation and removal of a current detection device at a detection location. [Structure] In addition to a first slit 45a for arranging a magnetic sensing element, a rectangular annular ferrite core 44 is formed with a second slit 45b for entering and exiting the core 44 of the object to be detected. . [Effect] Therefore, unlike the conventional case, the work of tightening and removing the screw becomes unnecessary, and the object to be detected can be inserted into and removed from the inside of the ferrite core 44 by passing through the second slit 45b. It is possible to extremely easily install and remove the relay box in and from the detection location.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a current detection device for detecting a current of a battery, a generator, etc. mounted on an automobile.

[0002]

[Prior art]

 A conventional current detecting device of this type is disclosed in, for example, Japanese Utility Model Laid-Open No. 62-46375, and basically, as shown in FIG. 6, a circular annular ferrite having a hole 1a at the center thereof. The core 1 is provided with a slit 1b extending in the radial direction thereof, and the magnetic sensitive element 2 such as a Hall element is provided as a detection sensor in the slit 1b to form a current detecting device.

Then, a detected body 3 through which a current flows is arranged in the hole 1a of the ferrite core 1, and a load current is actually passed through the detected body 3 in a direction of penetrating the paper surface of FIG. 6 from the front surface side to the back surface side. When a magnetic field is applied to the ferrite core 1, a magnetic field indicated by an arrow A is generated by the so-called right-handed screw law, and this magnetic field is detected by the magnetic sensitive element 2 in the slit 1b. A voltage is generated and output, and by reading the value of the load current corresponding to the value of the output voltage of the Hall element from the relationship between the previously determined hole voltage and the load current flowing through the detected object 3, The actual load current flowing through the detector 3 is detected.

As a modification of the configuration shown in FIG. 6, the ferrite core 4 is formed in a rectangular ring shape as shown in FIG. 7, and the ferrite core 4 is provided with a hole 4a and a slit 4b as in FIG. A magnetic sensing element may be disposed in the case. In practice, such a ferrite core 4 is housed in the case 5, and both sides of the case 5 facing the hole 4a are provided with insertion holes for inserting the test object. 6 are respectively provided so that the detected body 7 is inserted into the hole 4a through one insertion hole 6 and the detected body 7 is led out through the other insertion hole 6 and the detected body 7 is disposed. Even the circular annular ferrite core 1 shown in FIG. 6 is housed in a case similar to that shown in FIG.

By the way, the case of using the above-mentioned current detecting device for detecting the current of a bus bar in a relay box of an automobile will be described. FIG. 8 is an exploded perspective view of the relay box. In FIG. 8, 11 is a relay box. Main body, 12 and 13 are lids for closing the upper and lower surfaces of the main body 11, 14 is an insulating plate on which a plurality of relays 15, fuses 16 and fusible links 17 are mounted, and 18 are various connection terminals such as each relay 15 Insulating plates 21, 19 and 23 are mounted, bus bars through which a large current from the battery flows, and 24 are current detecting devices.

The current detecting device 24 is constructed as shown in FIG. 9, that is, a rectangular annular ferrite core 26 is arranged in a case 25, and a hall element 28 as a magnetic sensing element is provided in a slit 27 of the ferrite core 26. A detection circuit 29 having an IC configuration including an amplifier circuit for amplifying the output signal of the hall element 28 is provided, the hall element 28 and the detection circuit 29 are mounted on the printed circuit board 30, and the wiring pattern of the printed circuit board 30 is provided. The detection circuit 29 and a connector 31 for taking out its output to the outside are connected via a connector, and the opening of the case 25 is molded with the ferrite core 26, the printed circuit board 30 and the connector 31 housed in the case 25. ing.

In addition, a cylindrical guide body 32 for inserting an object to be detected is previously arranged in a hole at the center of the ferrite core 26, and is molded so that an end portion of the guide body 32 is exposed. By inserting the object to be detected into the guide body 32, the object to be detected is arranged in the hole of the ferrite core 26.

At this time, the bus bar 21 shown in FIG. 8 is inserted into the guide body 32 from one side of the case 25, and the end portion of the bus bar 21 is led out to the other side of the case 25, as shown in FIG. The ends of the busbars 21 and the other busbars 22 are connected by screws 32, whereby the current flowing through the busbars 21 and 22 is detected by the current detection device, and a detection signal is input to the ECU or the like via the connector 31. .

[0009]

[Problems to be solved by the device]

 However, in the conventional current detecting device 24, it is necessary to pierce the current detecting device 24 with the above-mentioned bus bar 21 when it is installed in a relay box or the like, and screw both the bus bars 21, 22 with the screw 32. When the current detecting device 24 has a problem and needs to be replaced anew, the screw 32 shown in FIG. 10 must be loosened and removed, the bus bars 21 and 22 must be separated, and the bus bar 21 must be removed. There is a problem that the 24 cannot be removed and replaced, which is very cumbersome and troublesome.

Therefore, the present invention has been made in order to solve the above-mentioned problems, and an object thereof is to make it possible to easily install and remove the current detection device at a detection position.

[0011]

[Means for Solving the Problems]

 A current detecting device according to the present invention comprises an annular core made of a magnetic material, a first slit formed in the core along a radial direction of the core, and a magnetic sensing element arranged in the first slit. An element; and a second slit formed in the core along the radial direction of the core and through which a current-flowing object to be detected is inserted into and removed from the inside of the core. .

[0012]

[Action]

 In this invention, the first slit for arranging the magnetic sensing element and the second slit for entering / exiting the inside of the core of the object to be detected are formed in the annular core, so that compared to the conventional case. It is extremely easy to install and remove the current detection device in the detection area such as the relay box.

[0013]

【Example】

 1 is an exploded perspective view of an embodiment of the current detecting device of the present invention, FIG. 2 is an exploded perspective view of a relay box, FIG. 3 is a partial perspective view of FIG. 2, and FIGS. Is.

First, the structure of the current detecting device will be described. As shown in FIG. 1, a case 41 having an inverted concave outer shape with one side opened is provided, and a rectangular shape is formed at a position corresponding to a recess 41 ′ of the case 41. A printed circuit board 42 having a cutout portion is provided, and frame bodies 43a and 43b are attached to both sides of the cutout portion of the printed circuit board 42, and a rectangular annular body is divided into left and right halves in both the frame bodies 43a and 43b. The left and right halves 44a and 44b of the ferrite core 44 having the above-mentioned shape are housed, respectively.

The ferrite core 44 is formed with a first slit 45a in which a magnetic sensing element such as a Hall element is arranged, and a second slit 45b for entering and exiting an object to be detected, which will be described later. When the printed circuit board 42 is housed in the case 41, the recess 41 ′ of the case 41 extends from the second slit 45 b to the center of the ferrite core 44.

Further, on the printed circuit board 42, a detection circuit 46 having an IC configuration including an amplifier circuit for amplifying the output of the Hall element and other circuit elements 47 are mounted, and the output of the detection circuit 46 is output to the outside. Is attached, the detection circuit 46 and the connector 48 are connected via a wiring pattern, and the opening of the case 41 is molded or closed by a lid while the printed circuit board 42 is accommodated in the case 41. The current detection device 49 is formed by being closed.

Reference numeral 50 denotes locking pieces provided on both side surfaces of the case 41, which are used when fixing the case 41 to the relay box.

Next, the schematic structure of the relay box incorporating the current detection device 49 shown in FIG. 1 will be described. Basically, it is almost the same as that of FIG. 8, and in FIG. , 53 are lids that close the upper and lower surfaces of the main body 51, 54 is an insulating plate on which a plurality of relays 55, fuses 56, and fusible links 57 are mounted, 58 is various connection terminals 59 of each relay 55, etc. Insulation plates 60, 61, etc. are mounted, and 62 is a bus bar as a detected body through which a large current from the battery flows, and a plate-shaped part 62d connecting the connecting parts 62b, 62c having a through hole 62a is formed. As shown in FIG. 3, the current detecting device 49 is housed in the relay box in a state where the current detecting device 49 is inserted into the recess 41 ′ of the case 41 of the current detecting device 49.

By the way, in order to examine the output characteristics of the current detecting device composed of the ferrite core 44 having the two slits 45a and 45b as described above, as shown in FIG. 4, both widths of both slits 45a and 45b are 2 mm. Then, a test wire W is provided as a detected object at the center of the ferrite core 44, and a load current I is made to flow from the front side to the back side on the paper surface of FIG. 4 to the first slit 45a. the output of the arranged hall element H via the amplifying unit a and the output circuit O _C constitute a measurement system to measure, when the load current I to the variable, the change in the Hall voltage of the Hall element H is in 5 It came to show in the solid line.

When compared with the output characteristics of the conventional current detection device shown by the alternate long and short dash line in FIG. 5, when the load current is the same, the value of the Hall voltage is the leakage due to one more slit than the conventional one. Although the magnetic flux has been reduced to about 1/3 of that of the conventional one, the linearity of the output characteristics has not been impaired, and the output voltage value can be reduced by increasing the amplification factor of the amplifier A. It can be dealt with without any practical problems.

Therefore, the current detecting device 49 can be attached or detached to or from the object to be detected such as the plate-shaped portion 62d of the bus bar 62 via the second slit 45b of the ferrite core 44, which is different from the conventional case. Since the work of tightening and removing the screws is unnecessary, the current detection device 49 can be extremely easily incorporated into and removed from the detection portion such as the relay box.

Further, the object to be detected is not limited to a fuse, a fusible link, a bus bar, etc., and may be any object having a shape that can pass through the second slit 45b of the ferrite core 44. Is large and efficient design is possible.

In the above embodiment, the case where the ferrite core 49 has a rectangular ring shape has been described, but it goes without saying that the ferrite core 49 may have a circular ring shape.

Further, the ferrite core 49 may be attached not only to the printed circuit board 42 side as shown in FIG. 1, but also to the case 41 side or the lid side that closes the opening of the case 41.

Further, the magnetic sensing element is not limited to the Hall element.

[0026]

[Effect of device]

 As described above, according to the current detecting device of the present invention, in addition to the first slit for disposing the magnetic sensing element, the second slit for inserting / removing the object to be detected into / from the core is provided in the annular core. Since it has been formed, it is possible to install and remove the current detection device to and from the detection area of the relay box, etc., much more easily than before, and it is possible to greatly improve the efficiency of installation and removal work. Moreover, it is possible to improve the degree of freedom of the detection location.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an embodiment of a current detecting device of the present invention.

FIG. 2 is an exploded perspective view of a relay box in which the device of FIG. 1 is incorporated.

3 is a perspective view of a part of FIG. 2. FIG.

FIG. 4 is a connection diagram of a test circuit for the output characteristic of FIG.

FIG. 5 is an output characteristic diagram of FIG.

FIG. 6 is a diagram illustrating the principle of a conventional current detection device.

FIG. 7 is a perspective view of another conventional current detection device.

FIG. 8 is an exploded perspective view of a general relay box.

9 is an exploded perspective view of a conventional current detection device attached to the relay box of FIG.

FIG. 10 is a perspective view of a conventional current detection device attached to the relay box of FIG.

[Explanation of symbols]

 44 Ferrite Core 45a First Slit 45b Second Slit 49 Current Detector H Hall Element

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Hirokazu Ito 1-14 Nishisuehiro-cho, Yokkaichi-shi, Mie Sumitomo Wiring Systems, Ltd.

Claims (1)

[Scope of utility model registration request] 1. An annular core made of a magnetic material, a first slit formed in the core along a radial direction of the core, a magnetic sensing element arranged in the first slit, and A current detection device, comprising: a second slit formed in the core along a radial direction of the core and through which a current-flowing object to be detected is inserted into and retracted from the inside of the core.