JPH0328380Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a so-called internal magnet type moving coil instrument.

(Prior Art) The structure of a conventional internal magnet type moving coil electric meter of this type is as shown in FIGS. 5A, 5B, and 5C.
Basically, a semicircular arc-shaped outer yoke 51 that also serves as a frame, a magnet 52 arranged inside, and an outer yoke 5
1, a semicircular separation yoke 53 that faces and fits into this, a pointer 54 supported by upper and lower bearings, a moving coil 55, a magnetic pole piece 56, a control spring 57, etc. In order to adjust the magnetic flux, a structure in which an appropriate iron piece is attached to bring the outer yoke 51 and the separation yoke 53 into close contact is generally used.

(Problem to be solved by the invention) However, even with the above conventional technology, the distribution of magnetic flux is still structurally non-uniform, so the relationship between the operating current value and the rotation angle of the pointer 54 does not have a linear characteristic. Nakatsuta. Specifically, regarding the instrument according to the prior art mentioned above, its characteristics are shown in a graph with the rotation angle θ on the X axis and the operating current value i on the Y axis, as shown in Figure 4A. Like,
In general, when the rotation angle of the pointer 54 is in the range of 5° to 45°, it is convex upward, and when it is in the range of 50° to 85°, it is curved convexly downward, resulting in a characteristic shown by an inverted S-shaped curve. It is.

These causes are due to a combination of various factors, such as a small gap in the fitting position (between both ends) between the separation yoke 53 and the outer circumferential yoke 51, and misalignment of the pole display groove of the magnet 52, and the magnetic flux density still remains low. This is because the non-uniformity is not completely eliminated.

In order to solve this problem, some models were equipped with appropriate correction iron pieces, but fine adjustment was difficult, skill and experience were essential for assembly, and it took a long time to complete assembly.

(Means for solving the problem) This idea was made in view of the above points, and does not require any special skills or experience during assembly, and can be easily machined without making delicate adjustments. Thus, it is possible to provide an internal magnet type meter that can obtain a linear relationship between the rotation angle of the pointer and the current value just by using the above-mentioned configuration.

The above-mentioned conventional internal magnet type moving coil instrument has both ends of the outer yoke and separation yoke brought into close contact with each other.
The idea was to create an even magnetic field by placing an iron piece on top of it, basically minimizing the leakage flux as much as possible. However, as mentioned above, such a method has limitations.

Therefore, in this invention, the idea is changed to artificially generate leakage magnetic flux, and furthermore, this leakage magnetic flux is actively used to correct the rotation angle-operating current value characteristic of the pointer.

Therefore, in this invention, first, the outer yoke that also serves as the frame is made into a semicircular arc shape (arc angle 180°), and its both ends are close to each magnetic pole of the magnet, that is, one end is N pole and the other end is S. The separation yoke has a quarter arc shape (arc angle
90°), a gap is created between the ends of both yokes, and these gaps are of the same length. Also, on the side of the outer yoke that is closer to one of the magnetic poles, there is a horizontally long horizontal line along the circumference. A substantially elliptical through hole was provided, and a recessed groove was bored in one end of the separation yoke located near the one magnetic pole side.

Further, the through hole is bored over a range of an arc angle of about 20° to 60° from the end of the outer yoke, while the groove is bored over a range of an arc angle of about 45° from the end of the separation yoke. The structure is characterized by the following.

(Function) The outer yoke is shaped like a semi-circular arc, and its ends are arranged so as to be close to each magnetic pole of the magnet, and the separation yoke is shaped like a quarter-circular arc to actively create the same gap between both yokes. Therefore, the magnetic flux of the magnet is more concentrated at the ends of both yokes. Since an elliptical through hole is bored in this outer yoke and a groove is also bored in the separation yoke, leakage magnetic flux is generated artificially, resulting in a distribution of magnetic flux almost as shown in Figure 3. It will be as shown. Note that in the figure, a represents an elliptical through hole, and b represents a concave groove.

When an operating current is passed through the moving coil under such a magnetic flux distribution state, the resulting magnetic flux and the magnetic flux from the magnet interact with each other, resulting in the so-called phenomenon shown in Figure 4A. The rotation angle-operating current characteristic of the S-shape is corrected to be linear. Therefore, by determining a predetermined position in advance through experiments and mechanically drilling a through hole and a groove at that position, the rotation angle-operating current characteristic can be adjusted without the need for fine adjustment as in the conventional method. It is possible to mass produce internal magnet-type instruments that have a linear relationship.

(Example) Hereinafter, an example of this invention will be described based on FIGS. 1 and 2. The outer yoke 1 which also serves as a frame used in this example has a semicircular arc shape and an inner diameter φ=12.4. The magnet 2 had a diameter φ of 9.4 mm and had both ends cut into a straight line by 0.7 mm each. Further, 3 is a quarter-arc-shaped separation yoke, 4 is a pointer, and 5 is a moving coil.

The outer yoke 1 is provided with a substantially elliptical through hole at an arc angle of about 20° to 60° from its end, and the separation yoke 3 is also bored at an arc angle of about 20° to 60° from its end.
A 45° groove is drilled. That is, as shown in FIG. 2A, a through hole a is bored in the range of -20° to -60° from the X-axis, centered on the axis of the pointer 4, and a hole a is also formed in the separation yoke 3. As shown in Fig. 2A, the concave groove b is located in the range of +45° to +90° from the X axis with the axis of the pointer 4 as the center.
is worn.

The size of the through hole a is 1/3 of the width of the outer circumferential yoke 1 in the vertical direction, that is, 7.0 mm x 1/3 ≒ 2.3 mm, and the horizontal size is 7.0 mm, which is the same as the width of the yoke 1. In the case of , the groove width is 1/3 of the width of the separation yoke 3, i.e. 7.0 mm x 1/3 ≒ 2.3
mm, and the notch length is 7.0 mm.

When the rotation angle-operating current characteristics of this embodiment according to the above configuration were confirmed through experiments, the results were as shown in Fig. 4B.
As shown in Figure 2, the rotation angle-operating current characteristics were almost linearly proportional.

(Effects of the invention) According to the internal magnet type instrument according to this invention, there is no need for an adjustment iron piece, etc. that was conventionally provided to correct non-uniformity of magnetic flux density, and no work is required to adjust it appropriately. becomes. Therefore, assembly can be performed easily and quickly. Also, it does not require any special skills or expertise.

In addition, in this invention, as is clear from the examples,
Since the above effects can be obtained without using external compensation pieces or magnetic pole pieces attached to the magnet, the number of parts and processing steps can be reduced, and the elements that disturb the magnetic field are reduced accordingly, achieving the design goal. Effects can be obtained.

Note that the most preferable results can be obtained at the positions where the through holes and grooves are bored as set in the above embodiments. However, due to its nature, the material of each member,
Although slight changes may occur due to changes in the form, etc., it is sufficient to determine the intended drilling position in advance through preliminary experiments, and thereafter mass-produce the same product in accordance with that position. Therefore, there is still no need for fine adjustment during assembly, and the assembly work can be done easily and quickly.

According to this invention, the movable inner magnet type has an outer circumferential yoke that also serves as a frame and has a substantially S-shaped characteristic as shown in FIG. In a coil meter, the current value characteristic is corrected for the rotation angle of the pointer, and a rotation angle-current value characteristic having a linear comparison relationship is obtained. Therefore, for example, the current to be measured and the voltage to be measured for the meter can be shown on a uniform scale.

[Brief explanation of drawings]

Figure 1 relates to an embodiment of this invention, in which Figure 1A is a plan view showing the arrangement of main components, Figure 1B is a front view of the same, Figure 1C is a right side view of the same, and Figure 1C is a right side view of the same.
Figure D is a front view of the separation yoke, and Figure 2 is an explanatory diagram showing the mutual positional relationship of the main components.
Figure 2 A is an explanatory diagram when the rotation angle of the pointer is 0°,
Figure 2B is an explanatory diagram when the rotation angle of the pointer is 90°.
Fig. 3 is an explanatory diagram showing the outline of the magnetic flux distribution state according to this invention, Fig. 4A is a graph showing the rotation angle-operating current value characteristic of the pointer according to the prior art, and Fig. 4B
5A, 5B, and 5C are graphs showing the rotation angle-operating current value characteristics of the pointer according to the embodiment, and FIGS. 5A, 5B, and 5C all relate to internal magnet type moving coil instruments according to the prior art, 5A is a perspective view, FIG. 5B is a plan view, and FIG. 5C is a side view. In the figure, 1 is an outer yoke, 2 is a magnet, 3 is a separation yoke, 4 is a pointer, 5 is a moving coil, a is a through hole, and b is a groove.

Claims (1)

[Scope of utility model registration request] In an internal magnet-type moving coil instrument that has an outer circumferential yoke that also serves as a frame and a separation yoke at a position opposite to this, the outer circumferential yoke is shaped like a semicircular arc and its ends are arranged so as to be close to each magnetic pole of the magnet. On the other hand, the separation yoke has a quarter-arc shape, and the gap between each end of the outer yoke and the separation yoke is the same, and on the side of the outer yoke that is closer to one of the magnetic poles, there is a gap along the circumferential direction. A horizontally elongated, approximately elliptical through hole is provided, and a recessed groove is bored in the circumferential direction at one end of the separation yoke located near the one magnetic pole side, and the through hole extends from the end of the outer peripheral yoke. The groove extends over an arc angle of about 20° to 60°, while the groove extends over an arc angle of about 45° from the end of the separation yoke.
Internal magnetic instrument.