JP2572627Y2 - Dynamic pressure bearing device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic bearing device used for a scanner motor or the like and having a dynamic bearing portion and a pivot bearing portion.

[0002]

2. Description of the Related Art Conventionally, as a dynamic bearing device of this kind,
FIG. 3A shows an example. In this dynamic pressure bearing device, a part of a shaft 41 is housed in a housing 42, and dynamic pressure grooves 43, 43 are provided on an outer peripheral surface of the shaft 41. When the shaft 41 rotates, the dynamic pressure groove 43
A dynamic pressure is generated in the air between the shaft 2 and the shaft 41 to support the shaft 41 in the radial direction. The dynamic pressure groove 43 and the inner peripheral surface of the housing 42 constitute a dynamic pressure bearing.

On the other hand, the inner bottom surface 42a of the housing 42
A ball 45 is fixed to the shaft 41, and a pivot bearing formed by the ball 45 and the shaft end surface 41 a of the shaft 41 is connected to the shaft 41.
Are supported in the axial direction.

FIG. 3B shows another dynamic pressure bearing device. In this dynamic pressure bearing device, a part of a shaft 52 fixed to a bottom plate 51 is housed in a housing 53,
2 are provided on the outer peripheral surface thereof, and when the housing 53 rotates, the dynamic pressure groove 55 is
A dynamic pressure is generated in the air between the shaft 3 and the shaft 52 to support the housing 53 in the radial direction. The dynamic pressure groove 55
And the inner peripheral surface of the housing 53 constitute a dynamic pressure bearing portion.

On the other hand, the shaft end 52a of the shaft 52 is formed into a spherical shape, and the shaft end 52a and the housing 53
A pivot bearing portion formed by the inner end face 53a of the first member supports the housing 53 in the axial direction.

[0006]

However, in the conventional dynamic pressure bearing device shown in FIGS. 3A and 3B, a pivot bearing portion exists in the dynamic pressure generating space of the dynamic pressure bearing portion. Therefore, there is a problem that abrasion powder generated in the pivot bearing portion may enter the bearing gap of the dynamic pressure bearing portion and hinder the operation of the dynamic pressure bearing portion.

Accordingly, an object of the present invention is to provide a dynamic pressure bearing device capable of preventing wear powder generated in a pivot bearing portion from entering a dynamic pressure bearing portion.

[0008]

In order to achieve the above object, the present invention provides a rotating body having an opening at an upper side and a bottom at a lower side, and a rotating body inserted through an opening of the rotating body. A shaft member that forms a dynamic pressure bearing portion with the peripheral surface, and a support member that forms a pivot bearing portion with the outer end surface of the bottom of the rotating body, and the rotating body is radially moved by the dynamic pressure bearing portion. In addition to the support, the rotating body is axially supported by the pivot bearing portion.

[0009]

Since the pivot bearing portion is provided outside the dynamic pressure bearing portion, it is possible to prevent wear powder generated in the pivot bearing portion from being mixed into the dynamic pressure bearing portion. Operation is maintained.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments.

The dynamic pressure bearing device of this embodiment constitutes a part of a scanner motor of an image input device, and as shown in FIG.
A part of the shaft 2 is housed in a bottomed sleeve 1 as a rotating body, and dynamic pressure grooves 3 are formed on an outer peripheral surface of the shaft 2 facing an inner peripheral surface of the bottomed sleeve 1. The dynamic pressure grooves 3, 3 of the shaft 2 and the inner peripheral surface of the bottomed sleeve 1 constitute a dynamic pressure bearing. The upper end in the axial direction in FIG. 1 of the outer peripheral surface of the shaft 2 is fixed to a cabinet 5 that covers the bottomed sleeve 1. A ball 7 is fixed to a conical groove 6 formed in the bottom of the cabinet 5 with an adhesive, and the ball 7 is in contact with the outer end surface 1 a of the bottomed sleeve 1. Outer end surface 1a of the bottomed sleeve 1
And the ball 7 constitute a pivot bearing portion.

A stator 8 is mounted on the inner peripheral surface of the cabinet 5, and a rotor 10 facing the stator 8 is mounted on an outer peripheral surface of the bottomed sleeve 1. A window 11 is formed on a side surface of the cabinet 5, and a mirror 12 facing the window 11 is mounted on an outer peripheral surface of the bottomed sleeve 1.

In the hydrodynamic bearing device having the above configuration, when the stator 8 generates a rotating magnetic field, the bottomed sleeve 1 on which the rotor 10 is mounted rotates. Then, the shaft 2
A dynamic pressure groove 3 formed in the groove 2 generates a dynamic pressure in the air between the bottomed sleeve 1 and the shaft 2, and this dynamic pressure radially supports the bottomed sleeve 1 as a rotating body. The ball 7 supports the bottomed sleeve 1 in the axial direction.

The laser beam incident from the window 11 of the cabinet 5 is reflected by a mirror 12 rotating integrally with the bottomed sleeve 1, and the laser beam is scanned in a plane.

The dynamic pressure bearing device comprises a pivot bearing portion formed by the ball 7 and the outer end surface 1a of the bottomed sleeve 1, and a dynamic pressure bearing formed by the dynamic pressure groove 3 and an inner peripheral surface of the bottomed sleeve 1. Parts are separated by the bottomed sleeve 1 itself. That is, the pivot bearing portion is provided outside the dynamic pressure bearing portion, and the bottomed sleeve 1 itself prevents wear powder generated in the pivot bearing portion from entering the dynamic pressure bearing portion. Good operation of the pressure bearing can be maintained.

Next, a reference example is shown in FIG. 2 as another embodiment. In this reference example, a part of a scanner motor is configured similarly to the above-described embodiment, and a part of a shaft 22 as a rotating body is housed in a bottomed sleeve 21.
The dynamic pressure groove 2 is formed on the outer peripheral surface of the shaft 22 facing the inner peripheral surface of the shaft 1.
3, 23 are formed. The dynamic pressure groove 23 and the inner peripheral surface of the bottomed sleeve 21 constitute a dynamic pressure bearing portion.

The upper end of the bottomed sleeve 21 in FIG. 2 is fixed to a cabinet 25 covering the shaft 22, and the lower end of the shaft 22 in FIG. Then, a support member 27 having a hemispherical projection is fixed to the inner bottom surface of the cabinet 25, and the support member 27 supports the shaft 22 in the axial direction via the support 26. The receiving base 26 and the support member 27 constitute a pivot bearing.

A stator 28 is mounted on an inner peripheral surface of the cabinet 25, and a rotor 30 facing the stator 28 is mounted on an outer peripheral surface of the receiving base 26. A window 31 is formed on a side surface of the cabinet 25, and a mirror 32 facing the window 31 is mounted on an outer peripheral surface of the shaft 22 in the axial lower side in FIG.

In the hydrodynamic bearing device having the above-described structure, when the stator 28 generates a rotating magnetic field, the cradle 26 on which the rotor 30 is mounted and the shaft 22 rotate. Then, the dynamic pressure groove 23 formed in the shaft 22 generates a dynamic pressure in the air between the bottomed sleeve 21 and the shaft 22, and the dynamic pressure radially supports the shaft 22 as a rotating body. In addition, the support member 27 supports the shaft 22 in the axial direction via the support 26.

The laser beam incident from the window 31 of the cabinet 25 is reflected by a mirror 32 rotating together with the shaft 22, and the laser beam is scanned in a plane.

In the hydrodynamic bearing device according to the reference example, the pivot bearing portion formed by the receiving base 26 and the support member 27 is formed by the hydrodynamic bearing portion formed by the hydrodynamic groove 23 and the inner peripheral surface of the bottomed sleeve 21. The pedestal 26, which is provided outside the supporting member 27 and covers the support member 27, prevents wear powder generated in the pivot bearing from entering the dynamic pressure bearing, so that the dynamic pressure bearing maintains good operation. it can.

In the above embodiments and reference examples, the dynamic pressure bearing device constituting the scanner motor has been described. However, the dynamic pressure bearing device of the present invention is not limited to the scanner motor, but may be a dynamic pressure bearing portion and a pivot bearing portion. Any type may be used as long as it has a dynamic pressure bearing device. Further, in the above embodiment and the reference example, the dynamic pressure groove is provided on the outer peripheral surface of the shaft, but the dynamic pressure groove may be provided on the inner peripheral surface of the bottomed sleeve.

[0023]

As is apparent from the above description, the dynamic bearing portion is formed on the inner peripheral surface of the rotating body, and the pivot bearing portion is formed on the outer end surface of the bottom portion of the rotating body. It is possible to prevent wear powder generated in the portion from being mixed into the dynamic pressure bearing portion, and it is possible to maintain good operation of the dynamic pressure bearing portion.

[Brief description of the drawings]

FIG. 1 is a sectional view of a first embodiment of the present invention.

FIG. 2 is a sectional view of a second embodiment of the present invention.

FIG. 3 is a sectional view of a conventional hydrodynamic bearing device.

[Explanation of symbols]

1,21 Bottom sleeve 2,22 Shaft 3,23 Dynamic pressure groove 5,25 Cabinet 6 Conical groove 7 Ball 8,28 Stator 10,30 Rotor 11,31 Window 12,32 Mirror 26 Cradle 27 Support member

Claims (1)

(57) [Scope of request for utility model registration] A rotating member having an opening on an upper side and a bottom portion on a lower side; a shaft member inserted through an opening of the rotating body and constituting a dynamic pressure bearing portion with an inner peripheral surface of the rotating body; A supporting member that constitutes a pivot bearing with the outer end surface of the bottom of the rotating body, wherein the rotating body is radially supported by the dynamic pressure bearing, and the rotating body is axially moved by the pivot bearing. A hydrodynamic bearing device characterized in that it is supported on a bearing.