JP2510346Y2 - Eddy current instrument - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial field of application) This invention relates to an overcurrent measuring instrument such as a vehicle speedometer,
Particularly, it relates to a structure for attaching a dial to a dial seat.

(Prior Art) In a vehicle speedometer or the like, a magnet is rotated by rotation of a rotating shaft, an induction plate is rotated by an eddy current generated by this rotation, and a speed is indicated by a pointer linked to the induction plate. Eddy current instruments are widely used.

FIG. 3 shows a conventional speedometer of this type. A rotary shaft 2 is rotatably supported on the frame 1 via a bearing (not shown), and the rotational force from the transmission is transmitted to the rotary shaft 2 via a flexible shaft (not shown). At the upper end of the rotary shaft 2 in the figure, a charcoal plate 3, a bush 4, a magnet 5 and a magnetic compensating plate 6 for temperature correction of the magnet 5.
Are fixed concentrically in sequence. A concave hole 2a is formed in the upper end portion of the rotary shaft 2, and a lower end 8a of a pointer shaft 8 is rotatably and concentrically supported in the concave hole 2a via a mortise receiver 7. In addition, a bowl-shaped guide plate 9 is provided in the middle of the pointer shaft 8.
Are fixed concentrically, and the outer wall of the charcoal plate 3 surrounds the outer periphery of the guide plate 9 to adjust the magnetic flux of the magnet 5. Further, the vicinity of the upper end of the pointer shaft 8 is rotatably supported by a bridge 11 which is a plate member provided on the upper portion of the main body case 10, and a portion of the spiral spring 12 where the pointer shaft 8 projects from the bridge 11 is rotatably supported. One end is fixed.
The other end of the spiral spring 12 is fixed to a part of the main body case 10 to give a predetermined braking force to the rotation of the pointer shaft 8, and the tip of the pointer shaft 8 has a pointer (not shown). Is attached.

The dial seat 18 supporting the dial 19 on which the scale pointed by the pointer is formed was attached to the bridge 11 as shown in FIG. That is, the dial 18 is the bridge 11
It is made of synthetic resin in the shape of a rectangular plate having a width substantially equal to that of the above, and cylindrical mounting seats 18a are integrally provided at both ends. A dial plate 19 is placed on the upper ends of these mounting seats 18a in the figure, and a set screw 20 is inserted into each through hole 19a formed at a position aligned with the mounting seat 18a.
Penetrates the mounting seat 18a and reaches the bridge 11. Then, the set screw 20 is rotated to self-tap on the bridge 11 to fix the dial plate 19 to the mounting seat 18a. Further, at the center position of the pair of mounting seats 18a, the dial plate seat 18 and the bridge 1
Through holes 18b and 11a having the same diameter are concentrically formed in the shaft 1, and a cylindrical true bearing 21 made of synthetic resin and fitted in a cylindrical shape is fitted into these through holes 18b and 11a. The pointer shaft 8 is rotatably inserted into the center of the induction bearing 21 and is held concentrically with the rotary shaft 2. In addition, the true bearing 21
A pair of arms 21a are symmetrically provided on the outer circumference of the bridge, and the tip of the arm 21a is bent upward in the figure to form a bridge 1a.
It penetrates through 1 and projects to the mounting seat 18a side. And arm 21
A hook 21b is formed at the tip of a, and the mounting seat 18a
Is locked in a groove 18c formed in the generatrix direction on the outer circumference. Reference numeral 22 in the figure is a thrust bearing provided on the pointer shaft 8.

On the other hand, a worm gear 13 is concentrically fixed to the rotary shaft 2 below the charcoal plate 3, and the rotation of the rotary shaft 2 is transmitted to a numeral wheel 17 of an integrator through gear trains 14, 15 and 16. It is like this.

With the above configuration, the rotation speed proportional to the traveling speed of the vehicle is transmitted from the transmission to the rotary shaft 2, and the magnet 5 is driven to rotate, so that a torque proportional to the rotation speed of the magnet 5 is generated by the eddy current action on the guide plate 9. Occurs,
The pointer shaft 8 is rotated to a position that is in balance with the braking force of the spiral spring 12 to indicate the speed on a dial (not shown).

(Problems to be solved by the invention) However, according to the above conventional dial plate mounting structure,
When attaching the dial to the bridge via the dial seat,
Since the metal setscrew is self-tapped to the bridge made of iron plate, etc., metal powder is generated and falls onto the bearing part of the pointer shaft, which may cause the pointer to run out, the indication error, and abnormal noise. Was there.

This invention was made in view of the above points, and prevents the generation of metal powder when the dial is attached to the bridge,
It is an object of the present invention to provide an eddy current instrument which can prevent the pointer from moving, an indication error, and an abnormal noise.

[Constitution of device]

(Means for Solving the Problems) In order to achieve the above object, the present invention is directed to a rotary shaft rotatably supported by a main body case, a magnet concentrically fixed to the rotary shaft, and a rotation of the magnet. A guide plate for generating a torque to drive the pointer shaft, an induction bearing mounted on a metallic plate member fixed to the front surface of the main body case to rotatably support the pointer shaft, and fixed to the plate member. In an eddy current instrument having a dial seat to which a dial is attached, the induction bearing is formed of a synthetic resin having a cylindrical fitting portion that penetrates the plate member and fits in the dial seat. In addition, the dial plate is self-tapped to the fitting portion of the induction bearing by a screw penetrating the dial plate seat.

(Operation) According to the above configuration, when the dial plate is screwed to the dial seat, a screw is attached to the fitting portion of the synthetic resin induction bearing fitted through the metal plate member and fitted in the dial seat. To join by self-tapping. Therefore, no metal powder is generated, and it is possible to prevent the pointer from fluctuating, an indication error, and noise.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

1 and 2 show an embodiment of this invention. In the figure, the same or equivalent parts as those of the conventional example shown in FIGS. 3 and 4 are designated by the same reference numerals and the description thereof will be omitted. The feature of this embodiment is that the bridge 11 which is a metal plate member of the dial plate 19 is used.
The structure of other parts is the same as the conventional example. Cylindrical fitting portions 21c are integrally provided in parallel with the pointer shaft 8 at the tips of the pair of arms 21a of the induction bearing 21. The fitting portion 21c penetrates the bridge 11 and is attached to the mounting seat 18 of the dial plate seat 18 provided in the upper portion of the bridge 11 in the figure.
It is fitted into the inside diameter of a from below. A hook portion 21d is provided so as to project on a part of the outer circumference of the fitting portion 21c, and the hook portion 21d is elastically locked to a groove portion 18c formed on the inner circumference of the mounting seat 18a. Then, the set screw 20 is inserted from a through hole 19a formed in the dial plate 19 and is self-tapped and fastened to a fitting portion 21c of the induction bearing 21.

According to this embodiment, since the set screw 20 is self-tapped to the fitting portion 21c formed of synthetic resin, the fitting portion 21c is elastically deformed and metal powder or the like is not generated. Therefore, it is possible to prevent the metal powder or the like from falling on the bearing portion of the pointer shaft 8 or the like, and causing the pointer to run out, the indication failure, or noise.

[Effect of device]

As described above, according to the present invention, the induction bearing of the eddy current instrument is formed of a synthetic resin having a cylindrical fitting portion that penetrates the metal plate member and fits in the dial seat. Since the dial is self-tap-fastened to the fitting portion of the guide bearing by the screw penetrating the dial seat, when the dial is attached to the metal plate member (bridge),
The fitting portion is only elastically deformed, and no metal powder or the like is generated. Therefore, it is possible to effectively prevent the problem that the metal powder or the like falls on the bearing portion of the pointer shaft and the like, which causes the pointer to run out, the indication failure, and the abnormal noise.

[Brief description of drawings]

FIG. 1 is a cross sectional view showing an embodiment of the present invention, FIG. 2 is a front view of the same, FIG. 3 is a partial cross sectional plan view of a conventional overcurrent type instrument, and FIG. FIG. 2 ... Rotating shaft 5 ... Magnet 8 ... Pointer shaft 9 ... Guide plate 10 ... Main body case 11 ... Plate member (bridge) 18 ... Dial plate seat 19 ... Dial plate 20 ... Set screw 21 ... Induction bearing 21c ... Fitting part

Claims (1)

(57) [Scope of utility model registration request] 1. A rotary shaft rotatably supported by a main body case, a magnet concentrically fixed to the rotary shaft, a guide plate for driving a pointer shaft by generating torque by the rotation of the magnet, and the main body. Eddy current instrument equipped with an induction bearing mounted on a metal plate member fixed to the front surface of the case to rotatably support the pointer shaft, and a dial seat fixed to the plate member and attached with a dial. In the above, the induction bearing is formed of synthetic resin having a cylindrical fitting portion that penetrates the plate member and fits in the dial seat, and the dial penetrates the dial seat. An eddy current type instrument characterized by being self-tapped to a fitting portion of the induction bearing by a screw.