JP3263771B2 - Bearing device for rotary decoration drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing for a rotary decoration driving device.

[0002]

2. Description of the Related Art Conventionally, bearing devices designed to reduce frictional resistance due to a thrust load by floating a vertical shaft by a magnetic repulsive force generated by facing a same magnetic pole surface of a permanent magnet to a variety of devices. Used.
The present applicant has made various proposals on a bearing device for rotationally driving a rotary decoration such as a table clock (for example, Japanese Utility Model Publication No. 59-27536). FIG. 3 is an outline of a rotary decoration driving device using a repulsive force of a permanent magnet in the prior art. The right half of the case 41 is formed to be high, and a storage portion 41a of the rotating shaft 42 is formed at the center of the upper surface. The rotating shaft 42 is erected on the case 1 via the storage portion 41 a, and the lower end is supported by a receiving plate 41 b in the case 41. Near the lower end of the rotating shaft 42, a ring-shaped first permanent magnet 43 is fixed so as to be integrally rotatable with the rotating shaft. A second permanent magnet 44 is fixed on the receiving plate 41b, and the rotary shaft 42 is loosely fitted in the center hole of the second permanent magnet 44. The first permanent magnet 43 and the second permanent magnet 44 have the same shape, and their opposing surfaces are magnetized to the same magnetic pole. The magnetic repulsive force of the two permanent magnets 43 and 44 reduces the frictional resistance when the rotating shaft 42 floats and rotates. Thus, even if various kinds of rotary decorations 45 are mounted on the upper end of the rotary shaft 42, energy consumption due to frictional resistance is reduced, battery life is prolonged, and smooth rotary motion is performed.

[0003]

Since the magnetic repulsion in the bearing device described above varies depending on the number of magnetic fluxes of the permanent magnet, the area of the facing surface, and the like, it is necessary to attach a permanent magnet corresponding to the weight of the rotating decoration. For this reason, even if the diameter of the rotating shaft is the same, it is necessary to prepare a permanent magnet having a different magnetic repulsion force every time the weight of the rotating ornament to be mounted is different, which causes an increase in cost accordingly. I have. SUMMARY OF THE INVENTION It is an object of the present invention to reduce the cost of a bearing device of a rotary decoration drive device by enabling a pair of permanent magnets to cope with different types of rotary decorations.

[0004]

In order to achieve the above object, according to the present invention, a rotating ornament is mounted on the upper end of a rotating shaft erected on a case, and is provided near the lower end of the rotating shaft. In the bearing device of the rotary decoration driving device, in which the load acting in the axial direction of the rotating shaft is reduced by the magnetic repulsive force of the pair of ring-shaped permanent magnets, each of the pair of permanent magnets has a flat surface. A flat part formed in a shape,
Each other surface is constituted by a step portion formed to have a different inner and outer thickness with a predetermined radius as a boundary,
The flat portions are magnetized to the same magnetic pole, and the step portions are respectively magnetized to magnetic poles opposite to the magnetic poles of the flat portion.

[0005]

The magnetic repulsion differs between when a pair of permanent magnets are mounted so that the flat portions face each other and when they are mounted so that the step portions face each other. Two types of magnetic repulsion can be obtained with the magnet.

[0006]

FIG. 1 shows a main part of an embodiment of the present invention. A rotating side permanent magnet 2 is attached to a rotating shaft 1 formed in a stepped rod shape.
Is fixed so as to be integrally rotatable therewith. The permanent magnet 2
One surface (the lower surface in FIG. 1) is a flat surface portion 2a formed in a flat shape, and the other surface (the upper surface in FIG. 1) has an outer periphery with a radius of about two-thirds of the radius from the radial direction. It is a step 2b formed to reduce the thickness of the side. The rotating shaft 1 has a right-angled step at the upper end of the fitting portion 1a with the rotating-side permanent magnet 2, and the upper portion thereof is a large-diameter portion 1b. Below the fitting portion 1a, a small-diameter portion 1c provided with a step so that it can be loosely fitted to a fixed permanent magnet 3 described later.
It has become. Flat portion (lower surface) 2 of rotating permanent magnet 2
A permanent magnet 3 on the fixed side having the same shape as the permanent magnet 2 on the rotating side is provided at a position opposed to a. The lower surface of the permanent magnet 3 on the fixed side is a rotary decoration driving device (not shown).
Is fixed to the upper surface of the base plate 4. In the pair of permanent magnets 2, 3, the plane portions 2a, 3a are respectively magnetized to the same magnetic pole (for example, both are S poles). Similarly, the step portions 2b and 3b are similarly magnetized to the same magnetic pole (for example, both have N poles). For this reason, as shown in FIG. 1, if the flat portions 2a and 3a are mounted so as to face each other, the same magnetic poles (S-poles) face each other. Force acts. For this reason, if the magnetic repulsion is greater than the weight of the rotating shaft 1 and the weight of a rotating decoration (not shown) attached to the upper end of the rotating shaft 1, the plane portions of the two magnets 2 and 3 are determined from the relationship between the two. An interval h is generated between 2a and 3a, and the lower end of the rotating shaft 1 floats from a bearing (not shown) so that the frictional resistance of the rotating shaft 1 hardly occurs. it can. FIG. 2 shows the permanent magnets 2 and 3 whose surfaces facing each other are reversed.
b and 3b face each other. Since the step portions 2b and 3b are magnetized to the same magnetic pole (N pole), the rotary shaft 1 is similarly lifted by the magnetic repulsive force in order to lift the rotary shaft 1.
Can reduce the frictional resistance. However, when the step portions 2b and 3b are set so as to face each other, the magnitude of the magnetic repulsion force is different from that of the flat portions 2a and
3a is different from that in the case where 3a are opposed to each other. The magnetic repulsion differs depending on factors such as the magnetic flux density, the area, and the distance between the opposing surfaces, and these elements change depending on the combination of the opposing surfaces as in the present invention. The magnetic repulsion is smaller between the flat surfaces than in the flat surfaces. As described above, even if the same pair of permanent magnets is used in a rotating decoration having a different weight, two types of magnetic repulsion can be obtained by using opposite combinations of the opposing surfaces. . Therefore, it is possible to reduce the number of types of permanent magnets to be mounted in half in response to the change in the weight of the rotary decoration, which is advantageous in terms of parts management and manufacturing costs. In addition,
In the present embodiment, the step portion is formed so as to reduce the thickness on the outer peripheral side. However, the reverse may be adopted, and the position of the boundary of the step may be arbitrarily provided in relation to the strength of the repulsive force. Good.
Further, the number of steps and the shape of the steps are not limited to those illustrated. The present invention is applicable to various vertical shaft bearing devices in addition to the rotary decoration drive device.

[0007]

As described above, according to the present invention, two types of magnetic repulsion can be obtained by a pair of permanent magnets. Since the number of types of magnets can be reduced by half, it contributes to a reduction in manufacturing costs and easy parts management.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state in which flat portions of a pair of permanent magnets are provided so as to face each other.

FIG. 2 is a cross-sectional view showing a state in which step portions of a pair of permanent magnets are provided so as to face each other.

FIG. 3 is a front view showing a rotary decoration driving device according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotation shaft 2, 3 Permanent magnet 2a, 3a Planar part 2b, 3b Step part

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-56-14973 (JP, A) JP-A-1-131190 (JP, U) JP-A-7-26795 (JP, U) JP-A 4- 99096 (JP, U) Jiko 59-27536 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) G04B 45/00

Claims (1)

(57) [Claims] 1. A rotating ornament is mounted on an upper end of a rotating shaft erected on a case, and the rotating ornament is provided by a pair of ring-shaped permanent magnets provided near a lower end of the rotating shaft. In the bearing device of the rotary decoration driving device configured to reduce a load applied in the axial direction of the shaft, the pair of permanent magnets may be configured such that one surface of each of the pair of permanent magnets is flat, and the other surface is a predetermined surface. And the step portions formed so that the inner and outer thicknesses are different from each other with the radius of the boundary as the boundary. Each of the flat portions is magnetized to the same magnetic pole, and each of the step portions has the flat portion. A bearing device for a rotary decoration drive device, wherein the bearing is magnetized to a magnetic pole opposite to the magnetic pole of the rotary ornament.