JPH02186118A - Rotating device - Google Patents

Abstract

PURPOSE:To aim at the stabilization of a bearing characteristic with out being too strict on axial dimension in spherical bearing parts provided at both ends of a rotating part by disposing a spherical body provided with a dynamic pressure generating groove at its peripheral surface on the upper side and a receiving member provided with a semi-spherical recessed part to be fitted at a spherical body on the lower side. CONSTITUTION:A lower spherical bearing part 12 located at the lower end part of a main spindle 18 is formed of a lower spherical body 22 provided with a dynamic pressure generating groove 26 at its peripheral surface coaxially with an axis of rotation, a lower receiving member 24 provided with a semi-spherical recessed part 23 to be fitted at the lower spherical body 22, and a lower cover 25 for preventing the outflow of lubricating oil. An upper spherical bearing part 13 to be fixed at the upper end part of the main spindle 18 is formed of an upper receiving member 28 provided with a semi-spherical recessed part 27 at its upper face, an upper spherical body 29, located at the upper part of the upper receiving member 28, to be fitted at a semi-spherical recessed part 27 and provided with a dynamic pressure generating groove 31 formed at its peripheral surface, and an upper cover 30. The upper spherical bearing part 13 is further supported by an axis 32, a linear bearing 33, and the like. Accordingly, axial dimensional accuracy can be moderated so as to like process assembling easy as well as the leakage of lubricant can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotation device suitable for a deflection device that scans laser light by rotating a polygon mirror, for example.

[Conventional technology]

In a laser printer, in order to print at high speed, it is necessary to rotate a polygon mirror that scans laser light at high speed.

A conventional rotating device for rotating a polygon mirror at high speed generally includes a rotating section 2 that supports a polygon mirror 1, as shown in FIG.
A structure is used in which the magnetic thrust bearing 3 floats the body without contact, and it is pivotally supported by a pair of dynamic pressure gas journal bearings 4.5.

Others (7) rf11a to L7c, e.g.
No. 200221, its structure is as follows:
As shown in FIG. 4, the rotating part 2 supporting the polygon mirror 1 is stored in the housing part 6, and the rotating part 2 is magnetically levitated between the rotating part 2 and the lower part of the housing part 6 to rotate. A drive section 7 is provided, and the upper and lower ends of the rotating section 2 are supported in a non-contact manner by a pair of hydrodynamic spherical bearings 8.9.

[Problem to be solved by the invention]

By the way, polygon mirrors such as those mentioned above require high-speed rotation of several thousand rotations per minute, so half-flecture occurs due to mismatch between the direction of axial displacement and the direction of the restoring force against that displacement. Rotation tends to become unstable due to sea whirl.

Therefore, in the structure shown in Fig. 3 in which the hydrodynamic gas journal bearings are fixedly arranged, it is necessary to strictly control the dimensional accuracy and coaxiality of both bearings, but it is necessary to strictly control the dimensional accuracy and coaxiality of both bearings. However, due to the complicated shape and large number of parts, it is very difficult to obtain desired processing and assembly accuracy, and the manufacturing cost also increases.

In addition, the upper and lower hydrodynamic spherical bearings shown in Fig. 4 are formed of a receiving member with a spherical body and a semi-concave spherical part, and are arranged in reverse under L, so that the spherical surface is In the bearing 8 whose body is located on the lower side, there is a problem in that lubricant leaks in the bearing gap especially when the bearing is stationary.

The 1iin of this invention was made to solve the above-mentioned problems, and it is not necessary to make the coaxiality or the axial dimension of each component strict, and it is possible to always obtain stable bearing characteristics. It is an object of the present invention to provide a rotating device that can prevent lubricant from leaking in gaps in a spherical bearing.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention includes a rotating part that rotates around a vertical rotation axis, and a non-contact spherical shaft support for the rotating part at both ends of the rotating part along the rotation axis. and a spherical bearing part at both ends, the spherical bearing part at both ends has a spherical body provided with a hydrodynamic groove on the outer circumferential surface on the upper side, and a semi-concave spherical part into which the spherical body fits. It has a structure in which it is arranged on the lower side.

[Effect]

Since both ends of the rotating part are supported by hydrodynamic spherical bearings, the rotating part can be supported in a non-contact manner, and both the upper and lower inner spherical bearings allow the support member to be placed downwards relative to the spherical body. This position prevents lubricant from leaking from the bearing gap.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2 of the accompanying drawings.

In the first example shown in FIG. 1, the rotating device is used in a light polarizing device for a laser printer.

In the same mouth, the rotating device includes a cylindrical rotating section 11, a lower spherical bearing section 12 that supports the rotating section 11 spherically in a non-contact manner at both ends along the rotational axis of the rotating section 11, and an upper spherical bearing section 12. A spherical bearing part 13, an upper spherical bearing support part 14 that supports the -F steel spherical bearing part 13 so as to be movable up and down, a drive part 15 that rotationally drives the rotating part 11, and a cylinder that houses these parts inside. It is composed of a shaped storage section 16.

The rotating part 11 includes a main shaft 18 made of steel, for example, with a flange 17 provided on the lower outer periphery, a polygon mirror 19 fixed to the lower part of the flange 17 of the main shaft 18, and a steel made main shaft 19 fixed to the upper and lower ends of the main shaft 18, respectively. The polygon mirror 19 consists of a flange 17 and a lower balance ring 20.
and is fixed to the main shaft 18.

The polygon mirror 19 is made of aluminum, and its outer peripheral surface is formed into a regular polygon by cutting.In order to reduce the axial displacement due to thermal expansion of the main shaft 18,
is fixed near the bottom edge of the

The lower spherical bearing part 12 includes a lower spherical body 22 provided coaxially with the rotational axis at the lower end of the main shaft 18, and
a lower receiving member 24 provided coaxially at the lower part thereof and having a semi-concave spherical part 23 on the upper surface into which the lower spherical body 22 fits;
It is formed by a lower cover 25 that surrounds the upper part of the lower receiving member 22 and prevents lubricant from flowing out, and a dynamic pressure generating groove 26 is provided on the outer peripheral surface of the lower spherical body 22.

The upper spherical bearing part 13 is fixed to the upper end of the main shaft 18 coaxially with the lower spherical bearing part 12, and has a semi-concave spherical part 27 on the upper surface.
an upper spherical body 29 which is arranged coaxially on the upper part of the upper receiving member 28 and fits into the semi-concave spherical part 27; It is formed with an upper cover 30 that prevents lubricant from flowing out,
Dynamic pressure generating grooves 31 are provided on the outer peripheral surface of the upper spherical body 29 .

The lower spherical body 22 of the lower spherical bearing part 12 and the upper spherical body 29 of the upper spherical bearing part 13 are both provided above the lower receiving member 24 and the upper receiving member 28, and the lower spherical bearing part 12 and the upper spherical bearing part 13 can hold the lubricant in the bearing gap.

The upper spherical bearing part 13 includes a shaft 32 provided at the upper part of the upper spherical body 2S, a linear bearing 33 that supports this shaft 32 in the radial direction, and a housing fixed to the storage part 16 so as to support this linear bearing 33. 34 and the shaft 32
A spring 35 is housed in the housing 34 so as to press the spring 35 downward, and a housing 3
It consists of a screw 36 threaded onto the top of the 4.

Since the upper spherical body 29 is movable in the axial direction by the sliding function of the upper spherical bearing support part 14, the axial movement of the upper bearing member 28 due to thermal expansion of the main shaft 18 closes the axial clearance of the spherical bearing. This prevents the bearing from changing and ensures stable bearing performance at all times.

The drive section 15 includes a cylindrical rotor 37 fixed to the main shaft 18, and a stator 39 fitted coaxially with the rotor 37 and fixed to the storage section 16 via a support ring 38.
It is formed into a cylindrical motor consisting of.

The storage section 16 also includes a disk-shaped bottom plate 40 that supports the lower receiving member 24, a cylindrical case 41 fixed on the bottom plate 40, and a housing 34 fixed on the case 41.
and a disc-shaped upper plate 4 to which the stator support ring 38 is attached.
A window 43 is provided around the case 41 at a position corresponding to the polygon mirror 19 and serves as an entrance and exit for laser light.

The first example of the present invention has the above configuration, and when power is supplied to the drive unit 15 and the rotating unit 11 is rotated at, for example, 30,000 rpm, the lower spherical body 22 and the upper spherical body 29 are rotated. Dynamic pressure is generated by dynamic pressure generating grooves provided on the outer circumferential surface. As a result, the axial clearances between the lower spherical body 22 and the lower receiving member 24 and between the upper spherical body 28 and the upper receiving member 28, which are O when at rest, are formed by the spring 36 contracting by a minute amount. The larger the axial clearance, the smaller the value of the generated dynamic pressure, so the axial clearance is automatically adjusted so that the force due to the dynamic pressure and the force due to the spring are equal. Therefore, the radial and axial loads of the rotating part 11 are supported in a non-contact manner by the lower spherical bearing part 12 and the upper spherical bearing part 13, and even during high-speed rotation, there is no rotational wobbling (stable rotation). Accuracy can be obtained,
Laser light can be scanned accurately. In addition, by readjusting the screw 36 of the upper spherical bearing support part 14 after the start of operation, the spring 35 can be
By changing the force with which the upper spherical body 29 is pushed, the present invention can be applied to rotating devices that frequently start and stop, or to rotating devices that require extremely high bearing rigidity.

Next, in the second example shown in FIG. 2, a flat motor is used as the drive unit in place of the cylindrical motor in the first example, and the upper spherical body 29 of the upper spherical bearing part 13 is provided with a screw structure. It is movable in the axial direction.

It should be noted that the same parts as those in the first example shown in FIG.

In FIG. 2, the flat motor serving as the drive unit 15 is
A disc-shaped stator 51 is fixed to the inner surface of the upper plate 42, and a disc-shaped rotor 53 is fixed on a support base 52 fixed to the main shaft 18 so as to face the stator 51.

The upper spherical bearing part 13 has a screw shaft 5 on the upper part of the upper spherical body 29.
4 in series, and by integrating the screw shaft 54 into the screw hole 55 formed in the upper plate 41 and rotating the screw shaft 54,
The bearing gap between the upper spherical body 29 and the upper receiving member 28 that constitute the upper spherical bearing support portion 14 can be freely adjusted.

In this second example, since a flat motor is adopted as the drive unit 15, the length of the main shaft 18 in the axial direction can be shortened, the amount of thermal expansion of the main shaft 18 is reduced, and the upper side of the upper spherical bearing part 13 is The structure in which the spherical body 29 can be vertically adjusted using the screw shaft 54 and the screw hole 55 can be adopted, and by reducing the number of parts, the device can be made smaller and lighter.

In both examples, the rotating device is not limited to an optical deflection device that scans laser beams, but can also be used for various devices that require high precision and high speed rotation, such as rotary tables for magnetic recording and audio disks. Applicable.

C Effects of the Invention As described above, according to the present invention, since the upper and lower parts of the rotating part are supported by the spherical bearing part in a non-contact manner, there is no need to make the bearings wt dense, and moreover, the upper spherical body is Since it is movable in the axial direction, it is not necessary to make the axial dimensions of each component part strict, and therefore processing and assembly are facilitated.

Furthermore, since the upper spherical body moves in the axial direction, it is not affected by thermal expansion of the rotating part due to heat generated in the spherical bearing part and the drive part, and stable bearing performance can always be obtained.

Further, in both the upper and lower spherical bearing parts, since the spherical body is provided at the upper part of the receiving member, it is possible to completely prevent leakage of lubricant in the gap between the spherical bearings, especially when the bearing is stationary.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing a first example of a rotating device according to the present invention, FIG. 2 is a vertical cross-sectional view showing a second example of the same, and FIGS. 3 and 4 are differences between conventional rotating devices. FIG. 11...Rotating part, 12...Lower spherical bearing part, 13...-E side spherical bearing part, 14...Upper spherical bearing support part, 15...
・Drive part, 16...Storage part, 18...
...Main axis, 19...Polygon mirror, 2
2...Lower spherical body, 23...Semi-concave spherical part, 24...Lower receiving member, 26...
Dynamic pressure generating groove, 27... Semi-concave spherical part, 28...
..."Second side receiving member, 29...Upper spherical body,
31...Dynamic pressure generation groove, 34...Housing, 35...Spring, 36...Screw, 54...Screw shaft, 55・・・・・・
・Screw hole. Patent applicant Nissqn Toyo Bearing Co., Ltd. Agent Aya Kamata Figure 1 Figure 2 Figure 3 Figure 1

Claims (2)

[Claims] (1) Consisting of a rotating part that rotates around a vertical rotation axis, and spherical bearing parts that spherically support the rotating part in a non-contact manner at both ends of the rotating part along the rotation axis, and The spherical bearing part of the part is formed by arranging a spherical body with a dynamic pressure generating groove on the outer circumferential surface on the upper side and a receiving member with a semi-concave spherical part in which this spherical body fits on the lower side. Rotating device. (2) The rotating device according to claim 1, wherein the spherical body of the upper spherical bearing is supported movably in the axial direction.