JPH06109765A - Indicating electrical instrument - Google Patents

Abstract

PURPOSE:To provide a high-precision meter through the improvement of dispersion of spring constants by improving the mounting status of a spiral spring used as a brake means. CONSTITUTION:Regarding an instrument where a spiral spring 10 is used as a means for braking the rotation of a pointer fitted to a rotational shaft 5, the spring 10 is constituted of an elastic body, and has a spiral shape formed on the same plane. Also, the structure of the spring 10 is such that engagement sections (a) and (b) integrally formed without any bending process are provided at both coiling start and finish ends. One engagement section (b) is fitted to one end of the painter, and the other engagement section (a) is fitted to a fixed member 9 inside the instrument.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called meter such as an ammeter and a voltmeter, and more particularly to a structure of a spiral spring used for braking a pointer.

[0002]

2. Description of the Related Art FIG. 4 is a diagram showing a configuration example of a main part of a conventional indicating electric meter (so-called meter), and shows an example of a movable iron piece type meter. In the figure, 1 is a fixed coil,
It is wound around a cylindrical bobbin 2. The outer circumference of the fixed coil 1 is magnetically shielded by a magnetic shield member 3. A cylindrical fixed iron piece 4 is provided on the inner circumference of the bobbin 2.
Reference numeral 5 denotes a rotary shaft, which is arranged so as to be located at the center of a cylindrical portion formed by the fixed iron piece 4, and both ends are rotatably supported by bearings (not shown). A movable iron piece 6 is attached to a portion of the rotary shaft 5 facing the fixed iron piece 4 with a predetermined gap therebetween, and a pointer 7 is fixed to a portion protruding from the fixed iron piece 4. The rear end of the pointer 7 is bent into an L-shape, and one end of a spiral spring 8 that functions as a control spring for braking the rotation of the pointer is soldered.
The other end of the spiral spring 8 is soldered to a mounting member 9 bent into an L shape. And the mounting member 9
Is fixed to a case (not shown).

In such a structure, the rotation angle of the pointer 7 is determined by the balance between the driving tokule generated by the magnetic energy of the current flowing through the fixed coil 1 and the braking tokule by the spiral spring 8. Therefore, when there are a plurality of meters with the same specifications, if there is variation in the braking torque due to the spiral spring 8 of each meter, the rotation angle of the pointer 7 of each meter ( The deflection angle) is different and will cause an indication error.

[0004]

The braking tokule of the spiral spring 8 is determined by the spring constant of the spiral spring 8, and the spring constant k is expressed by k = Ebt ³ / 12L. Here, E is the Young's modulus of the material, and L is the length of the spring.

However, the fixed portion (soldering position) of the conventional spiral spring 8 by soldering does not have a clear mark, and is positioned by using a jig. However, even if a mark is attached or an expensive jig is used, it is difficult to accurately determine the soldering position in manufacturing,
The effective length L of the spring varies. As a result, the spring constant varies.

Such a variation in the spring constant of the spiral spring 8 is an obstacle to improving the accuracy of the meter. The present invention has been made in view of such conventional problems, and an object thereof is to improve the mounting form of a spiral spring used as a braking means, thereby improving the variation in spring constant and achieving high accuracy. To provide an indicating electric meter.

[0007]

SUMMARY OF THE INVENTION The present invention is an instrument using a spiral spring as a means for braking the rotation of a pointer attached to a rotary shaft, wherein the spiral spring is made of an elastic body, and is arranged on the same plane. It is a manufactured spiral shape that has integrally formed locking parts at both ends of the spiral start and end without being bent, and one locking part at one end of the pointer. It is characterized in that the other locking portion is attached to a fixing member inside the instrument.

[0008]

The spiral spring of the present invention is formed on the same plane and has the engaging portions at the start and end of the spiral. Since this locking portion is integrally formed with the spiral spring body without bending, it is possible to perform dimensionally accurate processing.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a diagram showing a specific configuration example of an indicating electric meter according to the present invention, FIG. 2 is a diagram showing a configuration example of a spiral spring used in FIG. 1, and FIG. 3 is another configuration example of a spiral spring used in FIG. FIG.

In FIG. 1, the same parts as those in FIG. 4 are designated by the same reference numerals and their re-explanation is omitted. The drawing is different from FIG. 4 in the configuration of the spiral spring 10. The spiral spring 10 of the present application is formed on the same plane and has locking portions (a) and (b) at the start and end of winding of the spiral. The locking portions (a) and (b) are integrally formed with the spiral body without bending. Then, one locking portion (b) is attached to one end of the pointer, and the other locking portion (a) is attached to the mounting member 9 which is a fixing member inside the instrument.

FIG. 2 is a drawing (plan view) in which only the spiral spring 10 of FIG. 1 is extracted and drawn. As described above, the spiral spring of the present application has a structure including two locking portions (pin holes in FIG. 2) formed on the same plane. The spring length L of the spiral spring 10 can be remarkably accurately produced as compared with the conventional example. The reason is as follows.

By drawing directly on the upper surface of an elastic flat plate made of metal or the like with an electron beam apparatus as shown in FIG. 2, a spiral spring 10 having a shape as shown in FIG. 2 can be cut out. The dimensions of the spiral spring 10 of FIG. 2 drawn by the electron beam device can be machined very precisely.

It should be noted that the present invention does not limit the means for producing the shape shown in FIG. 2 to the electron beam apparatus. For example,
It may be created by etching using a photomask.

FIG. 3 shows another example of the structure of the spiral spring, and the spiral spring 11 can select the length L of the spring (the spring constant k can be selected). That is,
One locking portion (c) of the spiral is formed in a plurality of U-shapes. Therefore, the length L of the spring can be selected by mounting the plurality of desired U-shaped recessed positions on the mounting member 9.

That is, according to the spiral spring 11 of FIG.
One spiral spring can handle multiple sensitive meters. The Young's modulus may differ depending on the manufacturing lot of the elastic material forming the spiral spring. The reason is that the Young's modulus depends on the material mixing conditions, rolling conditions, and heat treatment conditions. Therefore, even if the dimensions of the spiral spring are accurately created, the spring constant k may differ depending on the manufacturing lot of the elastic material. However, according to the configuration of FIG. 3, since the spring constant k can be selected, this can be dealt with.

It should be noted that the effect obtained in the present application cannot be expected by a means of simply bending both ends thereof as shown in FIG. 5 instead of FIG. 2 and FIG. This is because the accuracy of bending (bending position) is inferior to that of processing by an electron beam device or the like.

[0017]

As described above, according to the present invention, a spiral spring having a constant spring length L can be manufactured, so that a spiral spring having a uniform braking force can be obtained. Therefore, a highly accurate indicating electric meter can be realized.

Further, since the spring constant can be selected, it is possible to cope with variations in the manufacturing lot of Young's modulus of the elastic body used as the material.

[Brief description of drawings]

FIG. 1 is a diagram showing a specific configuration example of an electric meter according to the present invention.

FIG. 2 is a diagram showing a configuration example of a spiral spring used in FIG.

FIG. 3 is a diagram showing another configuration example of the spiral spring used in FIG.

FIG. 4 is a diagram showing a specific configuration example of a conventional electric meter.

FIG. 5 is a diagram illustrating an unfavorable structure of a spiral spring.

[Explanation of symbols]

 1 fixed coil 2 bobbin 3 shielding member 4 fixed iron piece 5 rotating shaft 7 pointer 9 mounting member 10, 11 spiral spring

Claims (3)

[Claims] 1. An instrument using a spiral spring as a means for braking the rotation of a pointer attached to a rotary shaft, wherein the spiral spring is made of an elastic body and has a spiral shape formed on the same plane. It has a structure in which locking parts that are integrally molded without bending work are provided at both ends of the spiral winding start and winding.One locking part is attached to one end of the pointer and the other locking part is attached. An indicator electric meter characterized by being attached to a fixing member inside the meter. 2. The indicating electric meter according to claim 1, wherein the shape of the locking portion is a ring shape. 3. The indicating electric meter according to claim 1, wherein the shape of the locking portion is one or a plurality of U-shapes.