JPH0637338Y2 - Movable iron piece instrument - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION {Industrial application field} The present invention relates to an improvement of a movable iron piece instrument.

The movable iron piece type instrument generates a driving torque by the interaction between the fixed iron piece magnetized by the magnetic field generated by supplying the current to be measured to the fixed coil and the movable iron piece to rotate the movable part of the instrument, and the rotational position thereof. Is read with a pointer to measure the value of the measured current.

{Prior Art} A conventional iron piece configuration of such a movable iron piece instrument is shown in FIGS. 8 (A) and 8 (B). (A) shows the case of the repulsion type consisting of the fixed iron piece 1 and the movable iron piece 2, and (B) shows the case of the repulsion and suction type consisting of the pair of movable iron pieces 2 like the pair of fixed iron pieces 1. However, in both cases (A) and (B), the dimensions 1m and 1f of the facing iron pieces 1 and 2 are designed to be the same (1m = 1f).

When constructing a movable iron piece instrument, several parts are combined. In particular, stone screws are used in pivot type movable iron piece instruments. Depending on how the stone screw is adjusted, the positional relationship between the movable and fixed iron pieces varies. Furthermore,
Due to the dimensional variation when fixing (bonding) the iron pieces, the relative positions of the movable and fixed iron pieces are displaced in the assembled internal unit. As a result, in addition to variations in sensitivity due to variations in spring torque, variations in sensitivity occur due to variations in the positional relationship of the iron pieces. To correct it,
The position of the fixed iron piece is moved more than necessary to adjust the sensitivity, and the appearance characteristics are also affected, resulting in poor productivity.

{Problems to be solved by the invention} The present invention was made in order to solve such problems.
The purpose is to provide a movable iron piece instrument of this type, which is movable due to dimensional and assembly errors of parts, and which has small variations in sensitivity due to variations in the related dimensions of fixed iron pieces and which has good productivity. .

{Means for Solving the Problems} In order to achieve the above object, the present invention changes the size of the movable iron piece and the fixed iron piece in the rotation axis direction, and adjusts the relative position of the movable iron piece in the rotation direction with respect to the fixed iron piece. The cylinder member is rotatably mounted on the frame member as much as possible. Hereinafter, examples will be described in detail with reference to the drawings.

{Embodiment} FIG. 1 is a block diagram of an embodiment of an instrument according to the present invention.
(A) is a top view, (B) is a partial cross-sectional view seen from the X direction in (A), (C) is a partial cross-sectional view seen from the Y direction in (A), and FIG. ) And (B) are exploded perspective views of the main part of FIG. 1, and FIG. 3 is an assembled perspective view of FIG. 1 to 3, 10 is a movable shaft 11, a pointer support 12 fixed to the movable shaft 12, a pointer 13 attached to the support, a zero adjusting arm 14, and a coil spring attached to the zero adjusting arm. 14a, and a movable part of the instrument including a movable iron piece 15 attached to the movable shaft 11.

Reference numeral 20 is a cylindrical cylinder member (a perspective view of which is shown in FIG. 2 (A)) to which a fixed iron piece is attached. The opening has a disk-shaped flange 21, and the upper surface of this flange 21 is L-shaped. V-shaped protrusion 22a,
22b and arcuate holes 22c and 22d are formed. A through hole 24 is formed in the center of the bottom surface 23. A fixed iron piece 25 is attached to the outside of the cylindrical portion of the cylinder member 20 by adhesion or the like. Such a cylinder member 20 is made by turning or precision molding a plastic material.

Reference numeral 30 is a frame (a perspective view is shown in FIG. 2B) for holding a movable shaft to which a movable iron piece is attached, which is the cylinder
A disk 31 having the same shape as the flange 21 of 20, a disk 32 having a small diameter with the same central axis as the disk, and a body portion 33 connecting the disks 31 and 32.
Consists of. The disk 32 and the body 33 are the cylinder members described above.
It is inserted and arranged in the cylinder of 20, in which case the disc 32 is positioned in the through hole 24 formed in the center of the bottom surface 23 of the cylinder 20. The bridge 31 is on the upper side of the disc 31.
a and mounting arms 31 formed on both legs of this bridge
b, 31c are formed, and the notch 31 reaching the center of the disk 31
d, and a pair of arc-shaped holes 31e, 31 along the circumference of this disk
f is formed. Square holes 31g and 31h (31h is not shown in the figure) are formed at one end of each of the pair of holes into which the protrusions 22a and 22b formed on the cylinder member 20 are inserted. The frame member 30 having such a structure has a body portion 33.
The portion is used by being fitted into the cylinder of the cylinder member 20, and in that case, the projections 22a, 2 formed on the cylinder member 20 in the holes 31e, 31f formed on the disk 31 of the frame member 30.
2b is inserted from the square holes 31g and 31h, and has arc-shaped holes 31e and 31f.
Guided by the cylinder member 20, the cylinder member 20 can rotate within the range of the length of the pair of holes. Bridge 31
Screw holes 31i, 32a into which stone screws 41, 42 are screwed are formed respectively in the central portions of a and the disc 32, respectively. Like the cylinder member 20, the frame member 30 is integrally made of plastic by precision molding.

50 is an annular fixed coil, and the frame member is inside the annular ring.
The cylinder member 20 to which 30 is attached is inserted. A shield 60 is arranged so as to surround the fixed coil 50.

Here, as for the relational dimension between the movable iron piece 15 and the fixed iron piece 25, as shown in FIGS. 4 and 5, the length 1f of the fixed iron piece 25 is selected to be 1m <1f with respect to the length 1m of the movable iron piece 15. is there. That is,
In the embodiment of the present invention, as shown in FIG.
11mm and 1f = 13mm are selected. FIG. 6 (B) is a conventional one, and both 1f and 1m are selected to be 11 mm. In such a conventional structure, when the upper and lower relative positions of the movable iron piece 15 and the fixed iron piece 25 are deviated, the rate of change in sensitivity is as shown by the curve (B) in FIG. On the other hand, in the instrument of the present invention, the rate of change in sensitivity is extremely small, as shown by the curve (A) in FIG. In FIG. 7, the horizontal axis represents the deviation amount xmm between the edge portions of both iron pieces, and x = 0 when it is in the center.

Although the movable iron piece 15 is shorter than the fixed iron piece 25 in the above-described embodiment, the fixed iron piece may be shorter than the fixed iron piece 25.

{Effect of the present invention} As described above, in the present invention, the sizes of the movable iron piece and the fixed iron piece are configured so as to sufficiently absorb the relative positional deviation amount between the two iron pieces due to the usual assembly error. It is possible to obtain an instrument with stable sensitivity and less variation in the appearance characteristics. Moreover, the movement of the iron piece during adjustment can be minimized,
Adjustment man-hours are greatly reduced. In particular, in the case of the extended scale, the influence of the displacement between both iron pieces is great, but this can be eliminated in the present invention.

As described above, a structure in which the cylinder to which the fixed iron piece and the movable iron piece are attached is separated into a cylinder member to which the fixed iron piece is attached and a frame member that holds the movable iron piece was developed by the applicant of the present application and has already been filed. Is. With this configuration, if the upper and lower stone screws are attached to the frame member and the movable part is held by this, once the gap between the pivot and the stone screw is adjusted with the movable part incorporated, the instrument sensitivity When the adjustment or the adjustment to the extended scale is performed, it is not necessary to readjust the gap even if the cylinder member is rotated. In the movable iron piece type instrument having the structure in which the cylinder is divided into the cylinder member and the frame member in this manner, the amount of deviation of the relative position between both iron pieces due to the assembly error becomes large. The effect is extremely large by applying the present invention to various measuring instruments.

[Brief description of drawings]

1 (A) to 1 (C) are configuration diagrams of an embodiment of an instrument according to the present invention, in which (A) is a top view and (B) is a partial cross-sectional view seen from the X direction in (A). , (C) is a partial cross-sectional view seen from the Y direction in FIG. (A), FIGS. 2 (A) and (B) are exploded perspective views of the main part of the instrument according to the present invention, and FIG. 3 is the same. FIG. 4 is a perspective view of a measuring instrument according to the present invention, FIG. 4 and FIG. 5 are views showing configurations of a movable iron piece and a fixed iron piece used in the measuring instrument according to the present invention, and FIG. 6 is the present invention (A) and a conventional measuring instrument. Iron piece (B)
FIG. 7 is a diagram for explaining the size of FIG.
FIG. 8 (A) is a diagram for explaining the characteristics of FIG.
(B) is a figure for demonstrating the structure of the movable iron piece and fixed iron piece used for the conventional meter. 11 ... Movable part shaft, 20 ... Cylinder member, 30 ... Frame member,
15 ... Movable iron piece, 25 ... Fixed iron piece.

Claims (1)

[Scope of utility model registration request] 1. An instrument having a movable shaft having a movable iron piece mounted in a cylinder having a fixed iron piece, wherein the cylinder is provided with a cylinder member to which the fixed iron piece is attached, and a movable iron piece. The movable shaft is separated into a frame member for holding the movable shaft, the size of the movable iron piece and the fixed iron piece with respect to the rotation axis direction is changed, and the relative position in the rotation direction of the movable iron piece with respect to the fixed iron piece is adjustable. A movable iron piece type instrument in which a cylinder member is rotatably mounted on a frame member.