JPH0317211Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a pointer shaft bearing for a speedometer used in automobiles and the like.

Conventionally, such a device was shown in FIG. 1.

In the figure, 1 is a drive shaft, and frame 2
It is rotatably fixed in the center of the stem. 3
is a magnet, and 4 is a guide plate made of a magnetic material. When the rotation of a flexible shaft (not shown) is transmitted to the drive shaft 1 and the magnet 3 via the lower end connecting part 14, an eddy current is generated in the guide plate 4. occurs, and rotational torque is induced in the guide plate 4.

Reference numeral 5 designates the axis of the pointer 6, which rotates the guiding plate 4 under the control of the hairspring 7, and the scale on the dial 8 is rotated by the deflection of the pointer 6 fixed to the axis 5. Display speed.

Here, the pointer shaft 5 has a rotatable structure, with the tip end on the drive shaft 1 side being supported by a tenon receiver 9 and a bearing plate 10, and the pointer side being supported by a tenon screw 11. Adjust the tenon screw 11 in the vertical direction so that it can be used under certain conditions.
The axial displacement (so-called backlash) of the pointer shaft 5 is set within a certain range, and is fixed with a nut 12.

This adjustment requires high precision, so conventionally,
This was done using Bridge 13 screws.

However, the conventional configuration as described above has had the following drawbacks.

Adjusting the axial displacement of the pointer shaft 5 requires precision, which results in time-consuming work and low work efficiency.

In order to increase the adjustment accuracy, the tenon screw 11, bridge 13 and nut 12 are all threaded parts, thus increasing the manufacturing cost.

The amount of axial displacement of the pointer shaft 5 is related to the bearing 10, drive shaft 1, frame 2, bridge 13, tenon screw 11, and many other parts, and therefore it is necessary to improve the precision of each of these related parts. It was hot.

The purpose of the present invention is to overcome the drawbacks of the above-mentioned conventional technology, improve assembly ease by simplifying the structure,
An object of the present invention is to provide an improved pointer shaft bearing for a speedometer, which enables reduction in manufacturing costs and downsizing of the speedometer.

Hereinafter, the present invention will be specifically explained with reference to the drawings.

2 and 3 are sectional views of essential parts of a pointer shaft bearing of a speedometer according to an embodiment of the present invention.

In the same figure, 21 is the drive shaft, and the tenon receiver 2
2. The bearing 23 is fixedly held in the upper recess.

Reference numeral 24 denotes a pointer shaft, which fixedly holds the guide plate, hairspring, and pointer as in the conventional case (see FIG. 1), and is rotatable relative to the drive shaft 21.

What is important here is that a groove 25 is provided near the tip of the pointer shaft 24, and that the central hole 26 of the tenon receiver 22 is provided so as to form a radial bearing.

That is, although the diameter of the central hole 26 is slightly larger than the diameter of the groove 25, the tip portion 27 of the pointer shaft 24
has a slightly larger diameter than the central hole 26, and has a structure that prevents the pointer shaft 24 from coming out after it is pushed into the tenon receiver 22 from above and the tip 27 passes through the central hole 26.

For this reason, it is necessary that the tenon receiver 22 be made of an elastic member.

Another important point is that the axial length of the tip 27 of the pointer shaft 24 after insertion is slightly shorter than the inner height of the tenon receiver 22.

That is, as shown by a in FIG. 2, a minute clearance is provided.

As described above, the pointer shaft 24 is not only radially bearing on its lower end side, but also its movement in the strus direction is restricted, so that the axial displacement on the upper end side, unlike the conventional one shown in Fig. 1, is prevented. There is no need for adjustment, and the bearing member 28 that performs radial bearing on the upper end side of the pointer shaft 24 only needs to be caulked to the bridge 29 as shown in FIG.

The speedometer pointer shaft bearing of the present invention having such a configuration can provide the following effects.

To assemble, simply insert the pointer shaft firmly into the tenon receiver, and there is no need to adjust the amount of displacement in the axial direction, so assembly efficiency is improved with extremely simple work.

On the bridge side, there is no need for an adjustment mechanism for the amount of axial displacement, which simplifies the configuration.

Conventionally, the amount of axial displacement of the pointer shaft took into account the amount of thermal expansion of the frame and other parts, so it had a large displacement range, but with this invention, it is regulated only by the tenon receiver, so the amount of displacement can be reduced. (1/3 to 1/4 of the conventional amount), and vibration resistance is improved accordingly.

By simplifying the overall structure, the entire speedometer can be made smaller and manufacturing costs can be reduced.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional speedometer, and FIGS. 2 and 3 are enlarged sectional views of essential parts of a pointer shaft bearing of a speedometer according to an embodiment of the present invention. 21... Drive shaft, 22... Tenon bearing, 23... Bearing, 24... Pointer shaft, 25... Groove, 26... Central hole, 27... Tip, a... Clearance.

Claims (1)

[Scope of utility model registration request] Rotation of a magnet fixed to the drive shaft generates rotational torque on a guiding plate, a hairspring and a pointer are fixed to a pointer shaft that forms the rotation center of the guiding plate, and the hairspring controls the rotational torque to generate a pointer. In an eddy current speedometer that displays speed by vibration, a groove is provided near the tip of the pointer shaft on the driving shaft side, and a tenon bearing made of an elastic member is fitted into the groove to form a radial bearing. Also, a pointer shaft bearing for a speedometer, characterized in that a minute clearance in the axial direction is provided between the bearing at the tip of the pointer shaft and the tenon bearing.