JPH0719006Y2 - Magnet fixing part structure - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnet fixing part structure, and more particularly to a magnet fixing part structure for fixing a magnet in a predetermined position.

2. Description of the Related Art A cross-coil type instrument has a structure in which a magnetic field corresponding to a supplied signal current is generated by coils intersecting each other, and a rotating magnet having a pointer attached thereto is rotated by the generated magnetic field to perform an index. In addition, the cross-coil type meter has a structure in which the rotary magnet stops in place when the signal supply to the cross-coil is cut off when the power supply is turned off, and the pointer does not return to the reference position. It incorporates a zero-reset magnet for sucking and returning the pointer to the reference position.

The zero-reset magnet is fixed at a predetermined position close to the rotating magnet of the coil bobbin around which the coil is wound. Conventionally, as shown in FIGS. 5 and 6, a zero-reset magnet has a recess 19 having the same shape as the zero-removal magnet 18 and a slightly larger size as shown in FIGS. Insert the recess
The circumference of 19 was fixed by crimping or was fixed by an adhesive.

The problem to be solved by the invention is that, in the conventional zero coil magnet fixed part structure of the crossed coil type instrument, the zero coil magnet is inserted into a slightly larger concave part having substantially the same shape as the zero coil magnet provided in the resin coil bobbin. Then, it is fixed by adhesion or caulking, and fixing by adhesion is poor in workability and takes a lot of assembly man-hours.When caulking, caulking in the vicinity of the recessed portion, ferrite powder is sintered and molded. There was a problem that the caulking jig was easy to hit the zero-reduction magnet manufactured by the above, and the zero-reduction magnet might be broken.

The present invention has been made in view of the above points, and an object thereof is to provide a magnet fixing portion structure that can fix a magnet with good workability without damaging it.

Means for Solving the Problems The present invention relates to a magnet fixing portion structure for fixing a magnet at a predetermined position to be fixed, and an insertion portion formed in a shape to be fitted with the magnet and into which the magnet is inserted. And a groove formed continuously with the groove, and by plastically deforming the peripheral edge of the groove in the insertion direction, the insertion part connected to the groove is deformed to fix the magnet.

Effect According to the present invention, the groove portion is deformed by plastically deforming the peripheral edge of the groove portion away from the insertion portion toward the insertion portion, and the deformation of the groove portion deforms the peripheral edge of the insertion portion formed continuously with the groove portion, Since the magnet can be fixed while absorbing the excessive deformation of the insertion part by the groove part, when the insertion part is deformed by plastic deformation, the excessive deformation of the insertion part is absorbed by the groove part, and it is easy to control the plastic deformation force. In addition, since a large plastic deformation force can be applied by this, a margin can be provided for the plastic deformation position accuracy, and the magnet can be reliably fixed without damage while improving workability.

Embodiment FIG. 1 and FIG. 2 are perspective views of the essential parts of an embodiment of the present invention.

As shown in FIG. 3, the cross-coil type instrument has a rotating magnet 6 having a pointer shaft 5 fixed in a housing portion 4 of a coil bobbin 3 formed by a plastically deformable resin upper case 1 and a lower case 2. It is arranged in the state.

The coils 7 and 8 are wound around the coil bobbin 3 so as to intersect each other, and the coils 7 and 8 are connected to the substrate 11 via the connecting wire 10 fixed to the leg portion 9 of the lower case 2. substrate
At 11 is formed a circuit for generating a drive control signal for rotating the rotary magnet 6 according to a signal from the outside to give an instruction.

The coil 7 and 8 of the coil bobbin 3 are wound, and the portion in which the rotary magnet 6 is housed is surrounded by the magnetic shield case 12 so that it is not affected by the external magnetic field.

A recess 14 is provided at the bottom of a coil winding portion 13 for winding the coils 7, 8 of the lower case 2, and a zero-resetting magnet 15 is fixed in the recess 14. The zero-resetting magnet 15 has a cylindrical shape. Further, as shown in FIGS. 1 and 2, the concave portion 14 is composed of a cylindrical portion 14a into which the zero-reset magnet 15 is inserted and a groove portion 14b provided in a continuous manner with the cylindrical portion 14a. The cylindrical portion 14a is a magnet for zeroing
It has a cylindrical shape that is almost the same as the shape of 15, and its diameter is zero magnet 15
Is formed slightly larger than the diameter of. The groove portion 14b is provided continuously with the cylindrical portion 14a, the width thereof is set to be sufficiently smaller than the diameter of the cylindrical portion 14a, and the groove portion 14b is provided to a position sufficiently distant from the periphery of the cylindrical portion 14a.

When fixing the zero-reset magnet 15 to the cylindrical portion 14a, first, the zero-reset magnet 15 is inserted into the cylindrical portion 14a. Next, the cylindrical part on the groove 14b
Along the edge of the groove 14b, by forming a V-shaped groove 21 that plastically deforms the V-shaped groove 21 by, for example, driving a chisel-shaped caulking jig on the groove 14b at a position sufficiently separated from 14a ( Deformation occurs (arrows A ₁ , A ₂ , B ₁ , B ₂ directions), and as a result, a corner portion 14c serving as a boundary portion between the cylindrical portion 14a and the groove portion 14b.
Is deformed in the direction of the zero-reset magnet 15 and the zero-reset magnet 15 is
a Press inward to fix the zero-reset magnet 15 in the cylindrical portion 14.

At this time, when the driving force of the caulking jig is excessive and the deformation of the corner portion 14c is excessive, the corner portion 14c is deformed toward the inside of the groove portion 14b, and is configured so as not to apply excessive caulking to the zero-reset magnet 15. There is. By providing the groove portion 14b in this way, it is possible to absorb an excessive caulking force, and since it is not necessary to apply an excessive caulking force to the zero-reset magnet 15, it is possible to prevent damage to the zero-reset magnet 15 and also to control the caulking force. In addition to being easy, it is possible to give a margin to the crimping position accuracy.

Since the zero-reset magnet 15 can be fixed to the recess 14 by caulking a position sufficiently separated from the zero-reset magnet 15 in this way, the zero-removal magnet 15 is less likely to be hit by the caulking jig, and the zero-reset magnet 15 is It will not crack due to caulking and can be easily fixed by caulking, which has good workability.
Further, since the cylindrical portion 14a is deformed along the edge of the groove portion 14b by crimping a sufficiently distant position, the cylindrical portion 14a is deformed in the radial direction, pressing the zero-reset magnet 15 from the radial direction, and the cylindrical portion 14a. Also, cracking of the zero-reset magnet 15 at the time of deformation will not occur.

Further, as shown in FIG. 4, a plurality of cylindrical portions 16 may be provided over the entire surface of the lower case 2 facing the rotary magnet 6.

The plurality of cylindrical portions 16 are formed over the circumference of the rotary magnet 6, and the cylindrical portions 16a to 16f are formed so that the plurality of cylindrical portions 16 are continuous.
Grooves 17a to 17f having a width smaller than the diameter of the groove are formed. The zero-resetting magnet 15 is selected by inserting the cylindrical portion 16a from a plurality of cylindrical portions 16a to 16f according to the type of instrument. The zero-return magnet 15 is formed by caulking from the groove portions 17a and 17f formed on both sides of the cylindrical portion 16a in which the zero-return magnet 15 is inserted.
6a is deformed and fixed.

The groove portions 14b need not be provided on both sides of the cylindrical portion 14a,
It may be provided in one or more directions,
The point is that the cylindrical portion 14a may be deformed by crimping.

Further, the shape of the zero-reset magnet 15 and the cylindrical portion 14a which is the insertion portion thereof is not limited to the circular shape, and both may have a shape that can be fixed by caulking the zero-reset magnet 15. The shape of the groove 14b may be any structure and shape that can fix the zero-reset magnet 15 by crimping the position sufficiently far from the insertion portion of the zero-reset magnet 15.

Advantageous Effects of Invention As described above, according to the present invention, by providing a groove communicating with an insertion part for inserting a permanent magnet, the insertion part can be easily deformed by caulking the groove when fixing the magnet to the insertion part. Since it can be fixed to the permanent magnet, it is possible to caulk a place relatively distant from the permanent magnet, and therefore, it is possible to securely caulk the periphery of the magnet without accidentally caulking on the magnet. It has features such as not breaking.

[Brief description of drawings]

1 and 2 are perspective views of an embodiment of the present invention, FIG. 3 is a cross-sectional view of a cross-coil type instrument having the structure of an embodiment of the present invention, and FIG. 4 is another embodiment of the present invention. An example perspective view, FIG. 5 and FIG. 6 are perspective views of a conventional example. DESCRIPTION OF SYMBOLS 1 ... Upper case, 2 ... Lower case, 3 ... Coil bobbin, 14 ... Recessed part, 14a ... Cylindrical part, 14b ... Groove part, 15 ... Magnet for zeroing, 16a-16f ... Cylindrical part, 17a-17f ... Groove part.

Claims (1)

[Scope of utility model registration request] 1. A magnet fixing structure for fixing a magnet at a predetermined position to be fixed, comprising: an insertion part formed in a shape to be fitted with the magnet at the predetermined position and into which the magnet is inserted; A groove portion formed continuously, and by deforming the peripheral edge of the insertion portion continuous to the groove portion by plastically deforming the peripheral edge of the groove portion away from the insertion portion in the insertion portion direction, the groove portion A magnet fixing structure configured to fix the magnet to the insertion portion while absorbing excessive deformation of the insertion portion.