JPS5855864A - Moving-magnet instrument - Google Patents

Abstract

PURPOSE:To obtain an instrument which enables accurate returning of a pointer with a simple assembly by storing a bobbin containing a mobile magnet into a cylindrical case made of a magnetic material after it is wound with a coil while a return magnet is arranged in an excessive space. CONSTITUTION:The direction of the combined magnetic field is determined by the direction and the intensity of respective magnetic fields generated by current flowing through a coil 5 on one hand and of a returning magnet 9 on the other. Following the direction, a moving magnet 3 operates to incidate a gradation on a scale plate with a pointer 4. When current to the coil 5 is cut off, only the magnetic force of the returning magnet 9 works on the moving magnet 3 so that the moving magnet 3 is forcibly turned back being attracted by the returning magnet 9 securely arrayed. This enables the point 4 to return to the prescribed position on the scale plate.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a movable magnet type meter, and more particularly to a device for returning a pointer when the meter is not energized.

Generally, in the pointer return device of this type of movable magnet type instrument, a part of the movable part of the instrument, such as a movable magnet, is cut out or a weight is added to make the main point of the movable part unbalanced. Due to the distribution of double stars due to this imbalance, a method has been devised to restore the pointer by operating the movable part when the instrument is not energized. In this case, since one needle on the movable part of the meter is unbalanced, there is a problem in that the angle at which the meter is attached affects the indicated torque. In order to avoid this, methods have been taken in which a return ridge is formed in the movable part of the meter, or a return magnet is arranged in the meter body so as to face the movable magnet. However, in this case, there is a drawback that it takes time and effort to assemble the beard movement and return magnet to the instrument mechanism, which impedes productivity, and there is still a drawback that the main body of the III device itself becomes large.

This invention solves the above-mentioned problems by winding a coil around a synthetic resin bobbin containing a movable magnet, and by causing one end of the pointer shaft provided on the movable magnet to protrude from the bobbin pump S. A pointer is attached to the tip of the bobbin, and the bobbin is housed in a substantially cylindrical case made of magnetic material to block external disturbances such as earth's magnetism. A return magnet that can have a magnetic effect with the above-mentioned movable magnet is installed in the unused surplus space, allowing the use of existing movable magnet type instruments, and the simple assembly is easy and reliable. The pointer can be returned to its original position, and by forming the return magnet to be movable and adjustable within the space, the index characteristic can be arbitrarily set according to the distance between the magnetic poles with respect to the movable magnet. This makes it possible to adjust the finger strength extremely easily.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3, using a voltmeter as an example.

In the same figure, a movable magnet 3 is built in via a pointer shaft 2 in a bobbin 1 made of synthetic resin which is divided into upper and lower parts, and the upper end of the pointer shaft 2 protrudes from the upper end of the bobbin 1, and a pointer 4 is attached to the tip of the movable magnet 3. is fixed, and a coil 5 is wound around Bobi/1.

In addition, the bobby/1 has a built-in movable magnet 3, is a bearing part for the pointer shaft 2, and is also a frame body for the coil 5, and also has various terminals 6, which are formed by being routed from the coil 5 to the outside.
7, these are housed in a substantially cylindrical case 8 made of magnetic material so that they are not affected by external magnetic fields, such as earth's magnetism, and are formed to block disturbance factors. .

Therefore, in an unused surplus space between the main body of the bobbin 1 and the cylindrical case 8, a return magnet 9 that can exert a magnetic effect on the movable magnet 3 is disposed via a holder 10. .

When the above-mentioned movable magnet type meter is used as a voltmeter in a vehicle, etc., the magnetic field generated by the amount of current flowing through the coil 5 according to the voltage value of the vehicle, and the direction of the magnetic field generated by the amount of current flowing through the coil 5 are determined, and the movable magnet 3 The a'h street 4 is instructed in accordance with the scale and numerical value on a scale plate (not shown).

Furthermore, when the power to the indicating instrument is cut off, only the magnetic force of the return magnet 9 acts on the movable magnet 3, and the movably disposed movable magnet 3 eventually becomes a fixedly disposed return magnet. 9 and is forcibly rotated back, and along with this movement, the pointer 4 can be returned to a specified position on a scale plate (not shown).

In addition, by disposing a return magnet 9 that has a mutual magnetic effect with the movable magnet 3 in the surplus space between the main body of the bobbin 1 and the cylindrical case 8, it can be designed into an existing movable magnet type instrument. The return device can be constructed by simple assembly without modification.

Furthermore, by installing the returning magnet 9 so that its position can be adjusted vertically, the distance between the magnetic poles between the moving magnet 3 and the movable magnet 3 can be easily changed. By adjusting the force that interacts magnetically with 9, the composite Peltor direction can be variably adjusted as desired, and by adjusting this index characteristic, it is possible to easily and reliably indicate the corresponding scale on the scale plate. .

FIG. 4 shows another embodiment of the present invention, in which a movable magnet 3 is placed opposite to the outer periphery of the movable magnet 3 located in the surplus space between the bobbin l and the cylindrical case 8. By arranging the return magnet 9 so as to be movable and adjustable from the surface portion toward the inside of the case 8 via the screw adjustment means 11, the return mechanism of the finger holder 4 and the finger strength adjustment mechanism are realized. It is possible to construct a movable magnet type instrument having each of these, and it is possible to obtain the same effects as the above-mentioned embodiment.

In the above-mentioned embodiment, the return magnet 9 is disposed in the surplus space between the bobbin l and the cylindrical case 8 via the holder 10 and the screw adjustment means 11, but the return magnet 9 is The same effect can be obtained by molding it with a magnet or the like, placing it directly in the surplus space, and adjusting and moving it. This type of movable magnet type M device can also be applied to ammeters, thermometers, liquid level meters, etc.

[Brief explanation of the drawing]

Figures 1 to 3 show an embodiment of the present invention, with Figure 1 being a front view of this device and Figure 2 being A-A in Figure 1.
3 is an exploded #'1 diagram showing the main part of FIG. 1, and FIG. 4 is a sectional view of the main part showing another embodiment of the present invention. Bobbin 1 Pointer shaft 2 Movable magnet 3 Pointer 4 Coil 5 Terminals 6 and 7 Cylindrical case 8 Return magnet 9 Holder 10 Thread adjustment means 11 Applicant
Nippon Seiki Co., Ltd. @゛C',) No. J, (<ko Fig.

Claims (1)

[Scope of Claims] 1) A coil is wound around a synthetic resin pobbin containing a movable magnet, and the upper end of a pointer shaft provided on the movable magnet protrudes from the pobbin, and a finger hook is attached to the tip. death,
The bobbin is housed in a substantially cylindrical case made of magnetic material to block external magnetism, and a surplus space between the main body of the bobbin and the cylindrical case is provided with the movable magnet. A movable magnet type instrument characterized by being equipped with a return magnet that has a magnetic effect. 2) The movable magnet type instrument according to claim 1, wherein the return magnet is disposed within the surplus space so that its use can be adjusted as desired.