JPH0247500Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Application of the Invention) The present invention relates to a crossed-coil type instrument that can be expected to improve residual indication characteristics (needle placement) and reduce indication hysteresis.

(Background of the invention) As a conventional crossed coil type meter, for example,
There is something like the one shown in the figure. That is, this crossed coil type instrument includes a two-pole magnetized movable magnet 1,
A pointer shaft 2 passes through the center of the movable magnet 1 and is attached integrally with the movable magnet 1.
, a pointer 3 attached to the tip of the pointer shaft 2, upper and lower housings 4 and 5 made of non-magnetic material such as plastic, which rotatably hold the movable magnet 1 and the pointer shaft 2; a pair of crossed coils 6 and 7 wound around the upper and lower housings 4 and 5 so as to cross each other;
A cup-shaped magnetic shield case 8 made of a soft magnetic material is positioned to protect the outside of the coils 6 and 7 and is fixed to the column of the lower housing 5 by screws 9, and the upper housing 4
It consists of a dial plate 12 fixed by screws 11 to a support arm 10 that extends integrally from the pillar part of the dial, and by the action of this magnetic shield case 8,
The structure is such that external magnetism does not act on the movable magnet 1.

However, in the case of a crossed coil type instrument having such a structure, the magnetic shielding case 8 is made of electromagnetic soft iron.
It is made of a soft magnetic material with a relatively high coercive force such as SUY or pure iron containing 1% silicon, and therefore the residual magnetism generated in the case 8 is relatively large, so when the instrument is in the middle of operation, When the coil current is cut off, the movable magnet 1, which should remain stationary, rotates slightly, resulting in poor needle positioning.Furthermore, due to the relatively large residual magnetism, the movable magnet 1, which should remain stationary, rotates slightly. This also affected the rotation angle of the movable magnet 1, which caused the pointing angle of the pointer 3 to change, resulting in a problem that so-called pointing hysteresis occurred. By using a low coercive force material such as permalloy PB alloy as the material for the magnetic shield case 8, it is expected that the needle placement performance will be considerably improved and the indication hysteresis will be reduced. In the case of molding a cup-shaped magnetic shield case, it is difficult to obtain materials, and a large amount of alloy is required, and various molding molds are required, resulting in economical problems and high costs. There was a problem.

(Purpose of the invention) The present invention was made to eliminate such problems, and is equipped with a magnetically shielded case that can make the product cost relatively low, improve needle positioning performance, and reduce indication hysteresis. The purpose is to provide a crossed coil type instrument.

(Embodiment of the invention) The present invention will be explained in detail below based on the first embodiment shown in FIGS. teeth,
The reference numerals cited in the conventional example are attached to the structure in this embodiment, and a description of the structure will be omitted. That is, this embodiment has a feature in the structure of the magnetic shield case 13, and this magnetic shield case 13
is a non-magnetic material made of synthetic resin, etc., or
A cup-shaped outer frame 14 made of a relatively high-coercivity magnetic material made of low-cost iron plates such as SPCC, SPCD, and SPCE, and an amorphous alloy coated on the inner peripheral surface of the outer frame 14. It consists of a low coercive force thin plate 15. This thin plate 15 is
A thin tape-shaped amorphous amorphous alloy (with a thickness of about 25 microns for a normal amorphous aluminium alloy) is made by melting metals such as iron, cobalt, and nickel and metalloid elements such as silicon and boron and rapidly cooling them on a cooling roll. They are rolled into multiple layers and held together on the inner circumferential surface of the outer frame 14. Reference numeral 16 denotes a screw that fixes the outer frame 14 to the support section of the lower housing 5.

In this way, the magnetic shielding case 13 in this embodiment has a low coercive force thin plate 15 made of amorphous alloy rolled in multiple layers fitted into a cylindrical shape on the inner peripheral surface of the cup-shaped outer frame 14 made of a low-cost material. Therefore, the low coercive force thin plate 15 made of the amorphous alloy provides extremely effective magnetic shielding, improves needle positioning performance, and reduces indication hysteresis. Furthermore, since the low coercive force thin plate 15 described above can be cut into strips, material removal is easy and economical efficiency is improved.

In this first embodiment, the amorphous amorphous alloy 15 is rolled out of the tape-shaped amorphous alloy 15 inserted into the outer frame 14 by utilizing the force that naturally tends to spread due to the bending stress. Frame 14
However, if this tightness is insufficient, a retaining ring 17 made of synthetic resin or the like may be provided as in the second embodiment shown in FIG. Alternatively, as in the third embodiment shown in FIG. 4, a protrusion 18 may be provided at the upper end of the inner peripheral surface of the outer frame 14 to prevent the outer frame 14 from coming off upward. Furthermore, the ends of the amorphous alloy 15 may be fixed with an adhesive so that they do not roll up.

(Summary of the invention) As described above, the invention consists of a movable magnet 1 fixed to a pointer shaft 2, a plurality of intersecting coils 6 and 7 arranged in a cross-sectional manner so as to surround the movable magnet 1, and the intersecting coils. placed outside of 6 and 7,
and a magnetic shielding case 13 in which a tape-shaped low coercive force thin plate 15 made of an amorphous alloy is rolled and superposed in multiple layers on the inner surface of an outer frame 14 made of a non-magnetic material or a relatively high coercive force magnetic material. This is a cross-coil type instrument that is characterized by:

(Effect of the invention) Therefore, according to the invention, since the low coercive force material of the magnetic shielding case 13 used in the crossed coil type instrument is the low coercive force thin plate 15 made of a tape-shaped amorphous alloy. , while ordinary soft magnetic materials lose their springiness because they are heat-treated, that is, annealed, to obtain low coercive force characteristics, amorphous alloys have sufficient low coercive force characteristics even without heat treatment such as magnetic annealing. Therefore, it can be stably fitted into the outer frame 14 without impairing its springiness, and therefore a reliable fixing action can be obtained even in an environment where vibrations are applied. This can be understood from the fact that the Vickers hardness of permalloy, which is a normal soft magnetic material, is H _V 130, whereas the hardness of amorphous alloy is H _V 900. In addition, the low coercive force material of the present invention is a low coercive force thin plate 15 made of a tape-shaped amorphous alloy.
was rolled and polymerized multiple times on the inner surface of the outer frame 14 to form the magnetic shielding case 13. Since the amorphous alloy has a thin thickness of about 20 to 30 microns, the stress does not increase even when rolled, and the stress on the outside does not increase. Since the low coercive force characteristics do not change even when installed in the frame 14, the instrument can be operated when the instrument is not in operation, when the cross coils 6 and 7 are de-energized, without exerting any residual magnetism on the movable magnet inside. Not only can you obtain excellent needle positioning performance that maintains the normal indication at a low cost,
Unlike the case of a single thick magnetic plate, there is no magnetic flux leaking from the joint, and it is possible to prevent gaps from forming at the joint due to dimensional variations or thermal expansion of the outer frame 14.

Furthermore, in the present invention, even if the outer frame 14 is made of either a non-magnetic material or a magnetic material with a relatively high coercive force, the inner surface of the outer frame 14 has a low coercive force that is rolled and polymerized multiple times. The thin plate 15 provides reliable magnetic shielding and provides excellent effects such as a greater degree of freedom in designing the outer frame.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the first embodiment of the crossed coil type instrument according to the present invention, Fig. 2 is an exploded perspective view of only the magnetic shield case of the same, and Fig. 3 is the magnetic shield of the second embodiment of the present invention. FIG. 4 is a sectional view showing only the magnetic shielding case of the third embodiment of the present invention, and FIG. 5 is a sectional view showing a conventional crossed coil type meter. 1...Movable magnet, 2...Pointer shaft, 3...
Pointer, 4, 5... Upper and lower housing, 6, 7... Cross coil, 9, 11, 16... Mounting screw, 10...
... Support arm, 12 ... Dial plate, 13 ... Magnetic shield case, 14 ... Outer frame, 15 ... Amorphous amorphous thin plate with low coercive force, 17 ... Holding ring, 18 ...
…protrusion.

Claims (1)

[Scope of utility model registration request] A movable magnet 1 fixed to a pointer shaft 2, a plurality of intersecting coils 6, 7 arranged to cross each other so as to surround the movable magnet 1, and the intersecting coils 6,
7, a low coercive force thin plate 15 made of a tape-shaped amorphous alloy is rolled and superposed in multiple layers on the inner surface of an outer frame 14 made of a non-magnetic material or a magnetic material with a relatively high coercive force. A cross-coil type instrument characterized by comprising a shield case 13.