JPS5819488Y2 - Bearing structure of movable ring type small electric indicator - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a bearing structure for a movable ring type small electric indicator.

A conventional movable ring type small electric indicator is constructed as schematically shown in FIGS. 1 and 2.

That is, in these figures, what is denoted by reference numeral 1 is a frame formed in a substantially U-shape, to which is fixed a yoke 2 formed in a semi-cylindrical shape, and this yoke 2 has a second shape as shown in FIG. It is arranged to face one semi-cylindrical yoke 2 and forms one cylindrical yoke as a whole.

A cylindrical permanent magnet 4 is fixed to the inner center of the yoke 2 via a protrusion 3 that is formed integrally with the yoke 2 and projects.

A coil bobbin 5 formed in a substantially rectangular shape is arranged outside the cylindrical permanent magnet 4 so as to be able to rotate with sufficient margin.A coil 6 is wound around the circumferential surface of the coil bobbin 5, and the coil bobbin 5 is movable as a whole. A wire ring 7 is formed.

Holding members 9 are fixed above and below this coil 6 with an insulator 8 in between and an adhesive or the like.

As shown in FIG. 2, the holding member 9 includes an elongated substrate 9a and three concentric annular portions 9b to 9d protruding from the center thereof.

Of the holding members 9 having such a structure, a circular hole 10b formed in the base 10a of the pointer 10 is fitted into the annular portion 9C of the holding member 9 in the upper part in the drawing, and further above the ring-shaped part 9C, a fixing metal fitting 1 is fitted.
1 is provided, and its circular hole 11a is fitted into the annular stepped portion 9d to fix the pointer 10.

A hairspring 12 is disposed above this fixture 11, and the inner end of this hairspring 12 is fixed to the bent portion 11b of the fixture 11 by soldering or the like, and the outer end is not shown in the frame. It is soldered and fixed to one end of the zero-point adjustment arm provided above 1.

Note that the lower end of the rotating shaft 13 is press-fitted into a circular hole formed at the center of the small-diameter annular stepped portion 9d of the support member 9.

On the other hand, on the lower side of the coil 6, except for the pointer 10, an insulator 8, a holding member 9, a fixing metal fitting 11, etc. are arranged almost symmetrically with the upper side.

Furthermore, bearings 15 made of nylon resin as shown in FIGS. 3A and 3B are press-fitted into the upper and lower portions of the frame 1 through bushings 14 that serve as fitting portions, and the rotating shaft 13
is rotatably supported by these bearings 15.

Nylon was used for the bearing 15 due to its wear resistance, but as is well known, nylon has a particularly large dimensional change rate due to water absorption, so it was press-fitted after undergoing a humidity conditioning process.

However, since the outer diameter of the bearing after undergoing the humidity conditioning treatment process varies considerably, it becomes impossible to control the press-fit dimensions using a constant press force.

In other words, if the outer diameter becomes too large due to water absorption, the additional press-fit portion will cover the entire circumference, and it will not be possible to press it to the specified position with the normal press-in force, resulting in variations in press-fit dimensions. This caused the product to become defective.

The present invention was made to eliminate the above-mentioned drawbacks, and provides a product with stable quality in a bearing structure in which the bearing of the movable ring is made of synthetic resin such as nylon.
An embodiment of the present invention will be described below with reference to FIGS. 4A and 4B.

FIG. 4 shows the main part of the bearing structure according to the present invention, in which grooves having an involute spline cross section are formed on the outer peripheral surface of the bearing 18 along the direction in which the bearing 18 is inserted into the bushing 14. It is.

The overall length of the bearing 18 is longer than that of the bushing 14, so that when the bearing 18 is press-fitted into the bushing 14 to support the rotating shaft 13 of the movable wire ring 7, both ends of the bearing 18 It is configured to protrude from the bush 14.

With the above structure, even if the outer diameter becomes too large due to water absorption, the only part that will be press-fitted will be the protrusion at the outer end, as shown in Fig. 4B, and as shown in Fig. 3B. Since it is significantly reduced in comparison, the pressing force hardly changes even if the outer diameter varies.

Therefore, even if the outer diameter varies, it can be press-fitted to a predetermined position with a regular pressing force.

In addition, in the bearing 18 after the press-fit adjustment, the splines exposed from both ends of the bushing 14 recover elastically and swell slightly beyond the outside diameter of the press-fit part, and the elastically recovered splines function as flanges and are attached to the bush 14. It is securely fixed.

As is clear from the above explanation, by making the bearing outer shape into an inbonito spline shaft shape, the press-fitting dimensional accuracy is greatly improved, and at the same time, the press-fitting dimensional accuracy is maintained, which is an excellent practical effect.

Although this invention has been described with respect to the case where the bearing outer shape is an involute spline shaft shape, it is also possible to replace the bearing outer shape with a shape such as serrations that is relatively similar to the spline shape.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view of a conventional movable ring type small electric indicator, Fig. 2 is an exploded perspective view of the indicator shown in Fig. 1, and Fig. 3 A and B are bearings of the indicator shown in Fig. 1. FIGS. 4A and 4B are an enlarged partially cut-away front view and a cross-sectional view of the structure, showing an embodiment of the bearing structure of the movable ring type small electrical indicating instrument according to the present invention; FIGS. It is a diagram. 1...Frame, 4...Permanent magnet, 7
......Movable wire ring, 13...Rotating shaft, 15
．． 18...Bearing.

Claims (1)

[Scope of utility model registration request] A permanent magnet fixed to the frame, a movable wire ring placed on the outer periphery of the permanent magnet, a pair of rotating shafts installed above and below the movable wire ring, and a press-fitted fixed member into a fitting part provided on the frame. In a movable ring type small electrical indicator comprising a bearing entirely made of synthetic resin that rotatably supports the rotating shaft, the outer peripheral surface of at least one of the bearings is attached to the fitting portion of the bearing. A bearing structure for a small movable wire type electric indicator, characterized in that a groove having a spline-shaped cross section is formed along the direction of insertion, and both ends of the bearing protrude from the fitting part. .