JPS5852536Y2 - Movable iron piece type instrument - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a movable iron piece type instrument that allows easy adjustment of the twist angle of the pointer.

Movable iron-shaped instruments have a simple structure and good vibration resistance, so they are widely used in automobile ammeters and other applications.

FIG. 1 is an exploded perspective view of a conventional movable iron piece type instrument.

In the figure, 1 is a pointer, 2 is a dial, 3 is a mounting plate, 4 is a magnet with magnetic poles N and S, 5 is a base, and 5a is a base 5
6 is a terminal bar for connecting a lead wire fixed to the base 5; 7 is a movable iron piece; 7a;
7b is a magnetic pole part formed at both ends of the movable iron piece 70, 8 is a pointer shaft fixed to the center of the movable iron piece 7, 9 is a holding plate, and 9a is a bearing part formed at the center of the holding plate 9. ,
10 is a yoke formed in a U-shape; 10at10b is a yoke magnetic pole portion formed in two pieces (total of 4 pieces) at each end of the image of the yoke 10, penetrating the holding plate 9 and being bent on the front side thereof; Reference numeral 11 denotes a coil wound around the yoke 10, and both ends of the coil are connected to the terminal bar 6.

The yoke 10 and the coil 11 constitute a driving electromagnet.

The pointer shaft 8 is pivotally supported by the bearing hole 5a and the bearing portion 9a, and the movable iron piece 7 is rotatably disposed between the magnet 4 and the yoke magnetic pole portions 10a and 10b.

FIG. 2 is an explanatory diagram for explaining the operating principle of this meter.

During steady state, the movable iron piece 7 is attracted to the magnet 4 and the magnetic pole part 7
a t 7 b are opposed to the magnetic poles N and S, respectively, and are stopped at the zero stop position as shown in the figure.

At this time, the pointer 1 shown in FIG. 1 is pointing to the zero scale of the dial 2.

Here, current flows through the coil 11 and the yoke magnetic pole portion 10a
When is excited to the N pole and the yoke magnetic pole part 10b to the S pole, the magnetic pole parts 7a and 7b become the yoke magnetic pole part IQa,
10b, the movable iron piece 7 rotates in the direction of the arrow.

The movable iron piece 7 connects the magnet 4 to the magnetic pole portions 7 a y 7 b.
The attractive force of the magnetic poles N and S and the yoke magnetic pole part 10a.

It rotates to a position where the suction force of 10b is balanced and stops.

At this time, the scale corresponding to the value of the current flowing through the coil is indicated by the pointer.

In such a movable iron piece type meter, adjustment work is performed to change the magnetic force of the magnet in order to adjust the torsional angle accuracy of the pointer.

For this reason, in the past, this adjustment was made by magnetizing the magnets somewhat strongly and then demagnetizing them after assembly.

Cobalt-based cast magnets are generally used as magnets, but this type of magnet has a relatively small coercive force and is therefore easy to demagnetize.

However, in recent years, this type of magnet has become expensive due to a worldwide shortage of cobalt, so cheaper ferrite magnets have come to be used.

However, since ferrite magnets have extremely high coercive force, it is difficult to demagnetize them, making it difficult to adjust them sufficiently.
There was a drawback that the torsional angle accuracy of the pointer decreased.

The present invention was devised to eliminate these conventional drawbacks, and its purpose is to create a movable iron piece type instrument that can easily adjust the torsion angle accuracy of the pointer and provide highly accurate indicating characteristics. Our goal is to provide the following.

In order to achieve such an objective, the present invention consists of a magnet made of a plastic magnet, an adjustment screw made of magnetic material is screwed in so as to be movable along the center of the magnetic flux of the magnet, and the movement of the adjustment screw causes the movable iron piece of the magnet to move. It is designed to adjust the suction force against.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 3 is a longitudinal sectional view of one embodiment of the movable iron piece type meter according to the present invention, and FIG. 4 is a sectional view taken along line IV-IV thereof.

In the figure, the same or corresponding parts as in FIG. 1 are given the same reference numerals.

14a and 14b are plastic magnets in which ferrite powder is bound with plastic, and screw holes 15a pass through them in the direction of magnetization.

15b are formed respectively.

This plastic magnet 14 a t 14 b faces the magnetic pole portions 7 a , 7 b of the movable iron piece 7 with a predetermined interval in the radial direction, and its magnetic flux center line is aligned with the yoke magnetic pole portion 10 .
a.

It is arranged so as to be orthogonal to the magnetic flux center line of 10b when viewed from the plane.

Plastic magnet 14a. A base 5 made of non-magnetic material is fixed to the upper surface of 14b, and a holding plate 9 also made of non-magnetic material is fixed to the lower surface.

As can be seen from FIG. 4, the screw holes 15a and 15b are formed along the magnetic flux center line when viewed from above.

The plastic magnet 14a has an N pole on its inner surface and an S pole on its outer surface, and the plastic magnet 14b has an S pole on its inner surface.

The outer surface is magnetized to the north pole.

Also, a screw hole 15a. Adjustment screws 16a and 16b as adjusting bodies made of a magnetic material are respectively screwed into 15b from the outside.

In such a configuration, when the adjusting screw 15at16b is turned, the adjusting screw 1 (ia > 16b) moves in and out of the plastic magnet 14a t 14b.

As a result, the plastic magnet 14a. The permeance of the movable iron piece 7 changes, and the magnetic force that attracts the magnetic pole parts 7a and 7b of the movable iron piece 7 changes.

In this way, when the attractive force of the plastic magnets 14a, 14b to the movable iron piece 7 changes, the same yoke magnetic pole part 1
The rotation angle of the movable iron piece 70 changes with respect to the magnetic forces 0a and 10b.

In other words, the position of the equilibrium point of binocular attraction shifts.

FIG. 5 is a graph showing the relationship between the current flowing through the coil 11 of the drive electromagnet and the torsion angle of the pointer 1.

In the figure, A shows the characteristics when the adjusting screws 16a and 16b are screwed in deeply, the opening shows the characteristics when screwed in to a medium depth, and C shows the characteristics when screwed in shallowly.

If the adjustment screws l5a, 16b are screwed in a large amount, the attraction force of the plastic magnets 14a, 14b to the movable iron piece 7 will decrease, so the torsion angle will become relatively large, and if the adjustment screws l5a, 16b are screwed in a small amount, the attraction force will be relatively increased. The torsion angle becomes smaller.

Therefore, by turning the adjustment screw to move it in and out of the magnet, it is possible to change the torsion angle characteristics with respect to the coil current and easily adjust the torsion angle accuracy of the pointer.

As described above, the movable iron piece type instrument according to the present invention does not require the use of expensive cobalt-based magnets, and since there is no demagnetization process and only a slight operation of the adjustment body is required, the number of man-hours for adjusting the torsion angle is significantly reduced. By shortening the time to , the cost can be reduced.

In addition, since a plastic magnet is used, the adjustment screw that serves as the adjustment body can be screwed in smoothly and without loosening, and since the adjustment screw is moved along the magnetic flux center line when viewed from the plane, the magnetic force can be effectively changed. I can do it.

Furthermore, since the torsion angle of the pointer can be adjusted easily and accurately, the indication accuracy of the instrument can be improved, and there are many other excellent effects.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view of a conventional movable iron piece type meter, Fig. 2 is an explanatory diagram of its operating principle, Fig. 3 is a longitudinal sectional view of an embodiment of the movable iron piece type meter according to the present invention, and Fig. 4 is a IV-I in Figure 3
The V cross-sectional view and FIG. 5 are graphs showing the relationship between coil current and torsion angle. 1... Pointer, 2... Dial board, 5...
...Base, 7...Movable iron piece, 7a, 7b
...Magnetic pole part, 8...Pointer shaft, 9...
...Holding plate, 10...Yoke, 10a. 10b... Yoke magnetic pole part, 11... Coil, 14a. 14b...Plastic magnet, 15a, 1
5b... Screw hole, 15 a t 15 b...
...adjustment screw.

Claims (1)

[Scope of utility model registration request] A pointer shaft is rotatably supported, a movable iron piece with the pointer shaft fixed in the center, a magnet that attracts the movable iron piece to keep it in a zero still position, and a magnet that resists the attraction force of this magnet when it is energized. A movable iron piece-shaped instrument is equipped with a driving electromagnet that attracts and rotates the movable iron piece. A movable iron piece type instrument screwed in so as to be movable along a magnetic flux center line, and the attraction force of a magnet to the movable iron piece being adjusted by movement of the adjustment screw.