JPH04181011A - Dynamic pressure fluid bearing rotary device - Google Patents

Abstract

PURPOSE:To facilitate management after assembly by performing a thrust bearing function by a point contact executed through a pivot, making at least either of the pivot and a pivot support transformable for easy fitting when it is fitted in, and forming the above component into a shape which has a catching part in its slipping direction and is difficult to slip out after assembly. CONSTITUTION:A pivot 15 forming a thrust bearing is formed into an umbrella- shape, and made transformable for easy fitting when it is fitted in, and the umbrella part of the pivot 15 is caught by a flange 14a on the side of a pivot support, and thereby becomes difficult to slip out in the slipping direction of a rotary shaft 14. In the case of its assembly, the pivot 15 is first fixed to a sleeve 2 through an outer cylinder. A fixed quantity of lubricating fluid is poured into the bottom of the sleeve 2, and the rotary shaft 14 is fitted in the sleeve 2. In the case of fitting, the umbrella part of the pivot transforms not to obstruct the fitting of the rotary shaft, but after fitting, is caught by the flange 14a of the pivot support to prevent the rotary shaft from slipping out of the sleeve.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hydrodynamic bearing rotating device, and relates to a rotating device used, for example, in a deflection scanning device such as a laser beam printer.

[Conventional technology]

In recent years, the demand for high-speed or high-precision rotating devices has increased, and in particular, hydrodynamic bearings that perform high-precision, non-contact rotation are being used in laser beam printers and the like.

FIG. 7 shows a deflection scanning rotation device for a laser beam printer using a conventional hydrodynamic bearing. Rotating shaft 1 and sleeve 2
are rotatably fitted into each other.

A thrust plate 3 is arranged at the lower end of the sleeve 2 together with a fixed plate 4 and fixed to an outer cylinder 5.

A flange 6 is fixed to the rotating shaft 1, a rotating polygon mirror 7 is attached to the upper part of the flange 6, and a yoke 9 to which a magnet 8 for the driver 1 is fixed is fixed to the lower part. A stator 10 fixed to the outer cylinder 5 is arranged at a position facing the driving magnet 8. Here, a shallow groove 11 is carved in the thrust plate 3 on the surface facing the end of the rotating shaft 1, thereby forming a dynamic pressure thrust bearing. Furthermore, a herringbone-shaped shallow groove 12 is carved on the outer circumferential surface of the rotating shaft 1 at a position facing the inner circumferential surface of the sleeve 2, thereby forming a hydrodynamic radial bearing. Furthermore, near the sleeve opening, there is a shallow spiral groove 13 that allows lubricating fluid to flow into the dynamic pressure thrust bearing.
is engraved.

Here, a laser beam emitted from a light source (not shown) is applied to a rotating polygon mirror 7 to deflect and scan the laser beam.

[Issue 8 to be solved by the invention] However, in the above conventional example, after the assembly as a hydrodynamic bearing is completed, when an impact or the like is applied to the rotating body, or when the rotating body is carelessly lifted, the rotating body may be damaged. There were cases where it came out of the fixing member and damaged the hydrodynamic bearing. Therefore, it is difficult to handle the hydrodynamic bearing after assembly is completed. Furthermore, since a hydrodynamic bearing is used as the thrust bearing, processing and assembly costs are high.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and it is an object of the present invention to provide a hydrodynamic bearing rotating device that prevents a rotating body from accidentally falling off.

[Means and operations for solving the problem] In order to achieve the above-mentioned object, according to the present invention, the thrust bearing is provided in point contact with the pivot, and at least one of the sides of the pivot and the pivot receiver is connected to a member that fixes the rotating body. When inserted into the fixed member, it is deformed and easily inserted, and after assembly, the rotating body has a hook in the direction in which it comes out from the fixed member, making it difficult to come out. This prevents the rotating body from being lifted up or pulled out of the fixed member more than necessary.

(Example) FIG. 1 represents one embodiment of the invention.

The rotating shaft 14 and the sleeve 2 are rotatably fitted to each other. A pivot 15 is arranged at the lower end of the sleeve 2,
It is fixed to the outer cylinder 5. A flange 6 is fixed to the rotating shaft 14. The top of flange 6 has many rotating surfaces! t7 is attached, and a yoke 9 to which a driving magnet 8 is fixed is fixed to the lower part. A stator 10 fixed to the outer wIJ 5 is arranged at a position facing the drive magnet 8. Here, a herringbone-shaped shallow groove 12 is carved on the outer circumferential surface of the rotating shaft 14 at a position facing the inner circumferential surface of the sleeve 2, thereby forming a hydrodynamic radial bearing. A shallow spiral groove 13 is cut in the vicinity of the sleeve opening to allow lubricating fluid to flow into the dynamic pressure radial bearing. The shape of the pivot 15 that forms the thrust bearing is umbrella-shaped, and the umbrella part deforms when it is inserted, making it easy to fit in. In the direction in which the rotating shaft 14 comes out, the umbrella gets caught on the side flange part 14a and comes out. Make it difficult.

The detailed structure near the pivot will be explained. FIG. 2 is an enlarged view of the vicinity of the pivot, which is the main part of this embodiment.
FIG. 3 is a XX sectional view taken in the direction of the arrow in FIG. 2.

The pivot receiver of the rotating shaft 14 has a hole 14d with a diameter d on the side end surface.
will be established. Two square holes wider than the circumferential side are passed horizontally across this hole 14d. However, if the diameter of the pivot umbrella is a and the diameter of the pivot base is b, then
The relationship is b<d<a<h.

In the case of assembly, the pivot 15 is first fixed to the sleeve 2 via the outer cylinder. A certain amount of lubricating fluid is injected into the bottom of the sleeve 2, and the rotating shaft 14 is inserted into the sleeve. When fitting in, the umbrella part of the pivot deforms and does not prevent the rotation shaft from fitting in, but after fitting, the umbrella part deforms into the flange part 14 of the pivot receiver.
It gets caught in a and prevents the rotating shaft from coming out of the sleeve.

In this way, it can be easily assembled by pushing it into the sleeve, and after assembly, if a force is applied to the rotating shaft to try to pull it out of the sleeve, the umbrella part of the pivot will get caught on the collar of the pivot holder and be lifted up more than necessary. , to prevent it from coming out. Therefore, handling after assembly is completed is also easy.

FIG. 4 is an enlarged view of the vicinity of the pivot of the second embodiment of the present invention.

The shape of the pivot 16 is the rotation axis 1 inside the pivot (umbrella part).
Remove the thickness from the end face opposite to 4 to make it hollow. With such a configuration, the direction of deformation is defined, and the rotation axis 14 is easily deformed in the radial direction and less deformed in the axial direction.
When the pivot umbrella part is inserted into the sleeve 2, the hollow interior of the pivot umbrella part is deformed, and the umbrella part can be easily fitted into the sleeve 2 without being caught. Furthermore, if the hollow space is filled after fitting, deformation of the pivot can be suppressed, making it more difficult for the rotating shaft to come off.

FIG. 5 is an enlarged view of the vicinity of the pivot of a third embodiment of the present invention, and FIG. 6 is a diagram showing the collar portion 18 of this embodiment.

The pivot bearing consists of two parts: a rotating shaft part 17 with a shallow groove forming a radial bearing, and a collar part 18 to prevent removal.
(locking part). In the collar portion 18, if the diameter of the umbrella portion of the pivot is a, and the diameter of the pivot base is b, then the inner diameter of the collar portion d satisfies b<d<a, and a hole 18a is provided in the collar portion. Further processing is done by molding using resin.

By making the pivot support part into two parts, the internal shape of the pot support part side can be easily machined, and costs can be reduced. In addition, the material for the brim is made of resin, and the hole 1
By providing 8a, it is possible to easily deform the hole of diameter d in the collar portion in the radial direction when inserting the pivot.

In the embodiments, shaft rotation has been described, but sleeve rotation may also be used, and the groove may be provided on either the shaft or the sleeve. Also, the pivot may be located on the shaft, and similar effects can be obtained.

〔Effect of the invention〕

As explained above, the thrust bearing is made by point contact with the pivot, and the pivot and pivot bearing are shaped so that at least one of the sides is deformed and easily inserted, but after assembly, it is difficult to get caught in the direction of removal. shall be. This prevents the rotating body from being lifted up or pulled out of the fixed member more than necessary, making it easier to handle after assembly.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of the first embodiment of the present invention, and FIG. 2 is a configuration diagram of the first embodiment of the present invention.
3 is a sectional view of the main parts of the first embodiment, FIG. 4 is an enlarged view of the main parts of the second embodiment of the present invention, and FIG. 5 is the main part of the present invention. An enlarged view of the main parts of the third embodiment of the invention, FIG. 6 is a detailed view of the collar of the third embodiment, and FIG. 7 is a configuration diagram of a conventional hydrodynamic bearing rotating device. 1.14.17: Rotating axis, 2 sleeves, 7: Rotating polygon mirror, 15.16 + pivot. Figure 7

Claims (2)

[Claims] (1) It has a shaft and a sleeve that rotatably fit into each other, and a hydrodynamic radial bearing is configured between the outer peripheral surface of the shaft and the inner peripheral surface of the sleeve, and the end of the sleeve and the shaft A pivot that supports the shaft in point contact in the thrust direction is provided on one of the ends, and a pivot receiver that holds the pivot is provided on the other end, and the pivot and the pivot receiver are configured to be able to be elastically fitted into and locked into each other. A dynamic pressure fluid bearing rotating device characterized by: (2) the pivot has an open umbrella shape, and the pivot receiver has a hole for inserting the pivot that is smaller than the diameter of the umbrella;
2. The hydrodynamic bearing rotating device according to claim 1, wherein at least one of the pivot and the pivot receiver is made of an elastic material.