JPH0449913B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a current detector that detects a current in a main current path in a motor, inverter, etc. by insulating it and converting it into a voltage.

(Prior Art and its Problems) Conventionally, there is a current detector of this type that uses a Hall element. That is, as shown in FIG. 4, a magnetic flux generating coil 21 is directly wound around a toroidal core 20 for forming a magnetic circuit, and a Hall element 22 for detecting magnetic flux is placed in a magnetic gap g formed in a part of the toroidal core 20. Insert this Hall element 2
2 and the lead wire of the coil 21 to the external connection terminal plate 2.
There is one configured by connecting to 3.

However, in this Hall element type current detector, the toroidal core 20 must be supported by a suitable support member, and the Hall element 22 must also be provided at a predetermined position within the magnetic gap g. In some cases, the lead wires of the coil 21 must be connected to the external connection terminal board 23 by soldering through the lead wires 24 one by one, making it structurally difficult to miniaturize and also very difficult to assemble. The drawback was that it was complicated.

In addition, since the toroidal core 20 is generally formed by winding a thin sheet-like magnetic steel plate and has a ring shape with a portion cut out, the magnetic air gap g
There was a risk that this would spread, leading to variations in characteristics.

Further, since the coil 21 is directly wound around the toroidal core 20, if the insulation of either the coil 21 or the toroidal core 20 is broken, there is a risk that the toroidal core 20 and the coil 21 will be short-circuited.

(Means for Solving the Problems) The present invention has been proposed in view of the above points, and its objectives are to be able to be miniaturized, easy to assemble, and to prevent short circuits between the coil and the iron core. It is an object of the present invention to provide a current detector with a high efficiency.

That is, in order to achieve the above object, the present invention attaches the Hall element 8 to the printed circuit board 10,
This printed circuit board 10 is attached to the upper surface of the flange 3 of the coil bobbin 1, on which the pin terminal 5 connected to the terminal 8a of the Hall element 8 is implanted, and the coil 11 is wound around the outer periphery. A window 3 formed in the center of the flange 3
d, and the E-type iron core 9 is installed from the lower side of the coil bobbin 1, and the I-type iron core 7 is arranged on the upper part of the flange 3, and the central leg 9a of the E-type iron core 9 and the I-type iron core are installed. The gist is that the Hall element 8 is positioned within the magnetic gap g formed between the opposing surfaces of the magnets 7 and 7.

(Function) In the present invention, a coil bobbin is used to connect a magnetic flux generating coil, a magnetic circuit, a Hall element, etc., an iron core in which a magnetic gap is formed is incorporated in the coil bobbin, and a Hall element is attached to the coil bobbin. By incorporating a printed circuit board, each component can be integrated, making the current detector smaller, easier to assemble, stabilizing the characteristics, and improving the coil
This achieved high insulation between the iron cores.

(Embodiment) Fig. 1 is an exploded perspective view of a current detector according to an embodiment of the present invention. In the figure, 1 is a pin terminal type coil bobbin made of insulating synthetic resin, and this coil bobbin 1 is hollow. Flanges 3 and 4 are formed at both ends of the shaped body 2, and thick portions 3a and 3b are formed at both ends of one flange 3,
An appropriate number of pin terminals 5, 6 are implanted at intervals in these thick portions 3a, 3b, respectively. Also,
A recess 3c is formed in the center of the flange 3 for positioning and arranging an I-type iron core 7 made of laminated silicon steel plates, and a Hall element 8 is provided in the center of this recess 3c. A window 3d is formed for this purpose. In this case, the shape and size of the recess 3c and the window 3d correspond to the I-type iron core 7 and the Hall element 8. Note that a positioning and fixing part 4a for the E-shaped core 9 is also formed in the center of the other flange 4, corresponding to the recess 3c. The positioning fixing portion 4a has a rib structure extending parallel to each other, but may also be a recess.

Reference numeral 10 denotes a printed circuit board having a predetermined conductive part, including a hole 10a for attaching the terminal 8a of the Hall element 8 and a hole 10b for inserting the pin terminal 5.
is formed. Then, by bending the tip of the terminal 8a of the Hall element 8 into a substantially L shape and inserting the bent part into the hole 10a of the printed circuit board 10 from the bottom side, the Hall element 8 is attached to the printed circuit board 10. Installed. The printed circuit board 10 is disposed on the upper surface of one thick portion 3a of the flange 3 with the pin terminal 5 inserted into the hole 10b.
At this time, the terminal 8a of the Hall element 8 is located in a recess 3e formed approximately in the center of the thick portion 3a and on the side of the window 3d.
located in

A magnetic flux generating coil 11 is wound around the outer periphery of the body 2 of the coil bobbin 1, and the lead wires 11a at the beginning and end of winding of this coil 11 are connected to the other thick part 3b.
It is tied to the base of the pin terminal 6 through a groove 3f formed on the end face of the pin terminal 6.

Further, the central leg 9a of the E-type core 9, which forms a magnetic circuit together with the I-type core 7, is formed slightly shorter than both leg portions 9b, and the I-type core 7 is formed on the end surface of both leg portions 9b.
When the lower surfaces of the central leg 9a are brought into contact with each other, a magnetic gap g is formed between the end surface of the central leg 9a and the opposing lower surface of the I-shaped core 7, as shown in FIG. In this case, the magnetic gap g is E/I type iron cores 9, 7
Since the coil bobbin 1 is positioned and mounted at a predetermined position on the coil bobbin 1, the gap does not change unlike the magnetic gap of a toroidal core.

FIG. 2A is a perspective view of the present invention in an assembled state, and FIG. 2B is a longitudinal sectional view. When assembling, the Hall element 8 is attached to a printed circuit board 10, and this printed circuit board 10 is attached to a predetermined position on the flange 3 of the coil bobbin 1 around which the coil 11 is wound.
The portions where the respective lead wires 11a of No. 1 are tied to the pin terminals 6, the terminal portions of the Hall elements 8 attached to the printed circuit board 10, etc. are immersed in a solder bath or otherwise soldered. In this case, the Hall element 8 is arranged such that its upper surface is substantially flush with the upper surface of the recess 3c of the flange 3 into which the I-type iron core 7 is assembled.
located within. Next, if the E-type iron core 9 is installed from the lower side of the coil bobbin 1, and the I-type iron core 9 is installed from the upper side, the Hall element 8 will be inserted into the center leg 9a of the E-type iron core 9.
and the I-type iron core 7 facing the magnetic gap g formed by the I-type iron core 7, thereby forming a current detector. Note that the procedure for assembling the iron core may be reversed.

Thus, in this current detector, when a current flows through the coil 11, magnetic flux is generated, and this magnetic flux flows to the E/I iron cores 9, 7 forming a magnetic circuit.
In this case, the Hall element 8 is provided in the magnetic gap g of the magnetic circuit, and a magnetic field perpendicular to the surface of the Hall element 8 acts, so an electromotive force is generated due to the Hall effect. Flowing current can be detected.

(Effects of the Invention) As described above, according to the present invention, since the coil is wound around the coil bobbin, the printed circuit board having the Hall element, and the iron core forming the magnetic circuit are integrally incorporated, the size can be reduced. , and has the effect of facilitating assembly.

Also, instead of a toroidal iron core, E・I
type iron core, and these E and I type iron cores are assembled at predetermined positions of the coil bobbin to form a magnetic gap, which has the effect of keeping the magnetic gap constant.

Furthermore, since the coil is not wound directly around the iron core as in the past, the coil is wound around a coil bobbin, and the iron core is incorporated into this coil bobbin, so high insulation can be achieved.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view of one embodiment of the present invention;
Figure A is a perspective view showing the assembled state of the same as above, Figure B is a sectional view, Figure 3A is a front view of the E/I type iron core of the present invention,
Figure 4 is a side view, and Figure 4 is a conventional example. 1... Coil bobbin, 2... Body, 3, 4...
Flange, 3a, 3b...thick part, 3c...recess, 3d...window, 3e...recess, 3f...kerf,
5, 6... Pin terminal, 7... I-type core, 8... Hall element, 8a... Terminal, 9... E-type core, 9a
... Central leg, 10 ... Printed circuit board, 11 ... Coil.

Claims (1)

[Claims] 1 Attach the Hall element 8 to the printed circuit board 10,
This printed circuit board 10 is attached to the upper surface of the flange 3 of the coil bobbin 1, on which the pin terminal 5 connected to the terminal 8a of the Hall element 8 is implanted, and the coil 11 is wound around the outer periphery. A window 3 formed in the center of the flange 3
d, and the E-type iron core 9 is installed from the lower side of the coil bobbin 1, and the I-type iron core 7 is arranged on the upper part of the flange 3, and the central leg 9a of the E-type iron core 9 and the I-type A current detector characterized in that the Hall element 8 is positioned within a magnetic gap g formed between opposing surfaces of an iron core 7.