JPH0626053U - Bearing device - Google Patents

Abstract

(57) [Abstract] [Purpose] To enable axial fixing in a bearing device in which a shaft is supported by a cylindrical bearing and a thrust bearing. [Structure] The rotating shaft 1 is supported by a cylindrical bearing 2, and the thrust bearing 10 is composed of a magnet magnetized in the axial direction. The thrust bearing 10 is supported on the cylindrical bearing side via a base plate 11. [Effect] According to the above configuration, since the rotary shaft 1 and the thrust bearing 10 are in direct contact with each other, a small magnet can obtain a high attracting force in the thrust direction, and the shaft can be fixed in the axial direction.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to improvement of a bearing device for a motor that drives a floppy disk, a hard disk, or the like.

[0002]

[Prior art]

 Conventionally, ball bearings are often used as the bearings of the rotary shaft of this type of motor. However, as shown in FIG. 7, a dynamic pressure bearing is used to support a rotating shaft having a herringbone-shaped groove on its outer peripheral surface with a cylindrical bearing in order to improve the shaft runout or reduce the size of the flattening.

In FIG. 7, 1 is a rotary shaft, 1 a is a herringbone-shaped groove formed on its peripheral surface, 2 is a cylindrical bearing, 3 is a thrust bearing, 4 is a hub, 5 is a base plate, and 6 is a drive magnet. A net, 7 is a stator core, 8 is a drive coil, 9 is a magnet attached to the outer peripheral surface of the hub, and 10 is lubricating oil.

[0004]

[Problems to be solved by the device]

 The bearing device having the above configuration cannot be fixed in the axial direction. Therefore, as an axial fixing means, the attractive force between the drive magnet 6 and the stator core 7 is utilized, and further, the magnet 9 provided on the outer peripheral surface of the hub 4 and the magnetic force between the base plate 5 made of an iron plate. A means of utilizing the suction force is taken.

However, in any of the above means, since the suction force acts on the circumference having a certain radius from the rotation axis, the difference in the suction forces at the positions on the circumference due to a slight inclination of the axis. However, it acts as a couple on the bearing and causes shaft deflection during rotation. In addition, using a large-diameter magnet 9 and using a magnetic plate as the material of the base plate 5 is disadvantageous in terms of cost or design.

[0006]

[The purpose of the device]

 The present invention has been made in order to solve the above-mentioned problems, and a bearing device that does not cause shaft deflection, can be reliably fixed in the axial direction, and is extremely advantageous in terms of cost and design. Is intended to provide.

[0007]

[Means for Solving the Problems]

 According to the present invention, in a bearing device including a shaft, a cylindrical bearing that supports the shaft, and a thrust bearing, the thrust bearing is composed of a magnet magnetized in an axial direction, and the thrust bearing is a base. The gist is that it is supported by a base plate that closes the cylindrical bearing through the material.

[0008]

[Action]

 According to the above configuration, since the shaft and the thrust bearing including the magnet are in direct contact with each other, a small magnet can obtain a high attraction force in the thrust direction and can fix the shaft in the axial direction. Moreover, since the thrust bearing is magnetized in the axial direction, no couple force is generated.

[0009]

【Example】

 FIG. 1 shows an embodiment of the present invention. The same or similar members as in FIG. 7 are designated by the same reference numerals. In FIG. 1, 1 is a rotating shaft, 2 is a cylindrical bearing, 10 is a thrust bearing made of a magnet magnetized in the axial direction, 11 is a base plate. It supports the bearing 2 and closes the end face of the cylindrical bearing. Reference numeral 12 is a sump of lubricating oil.

FIG. 2 shows another embodiment. In this example, the thrust bearing 10 of the magnet does not directly receive the shaft, and a thin plate-shaped spacer 13 made of a magnetic material is sandwiched in between.

In the configuration of FIGS. 1 and 2, the oil sump 12 is filled with the lubricating oil, so that the wear is less, but in order to further improve the wear resistance, the surface of the magnet 10 or the spacer 13 is spirally shaped. The groove 14 may be provided to provide a dynamic pressure bearing function.

The shaft 1 may be a normal cylindrical shaft having no groove for generating dynamic pressure. It is preferable to use a ferromagnetic material such as steel or quench hardening type stainless steel as the material of the shaft.

According to the configuration of the bearing device described above, since the shaft and the thrust bearing of the magnet are in direct contact with each other, a small magnet can obtain a high attraction force in the axial direction, and a supporting force in the axial direction of the shaft can be obtained. can get. Even when the spacer 13 is interposed, the same effect can be obtained by making it extremely thin or by using a ferromagnetic material such as hardened steel.

Further, since it is not necessary to make the base plate 11 a ferromagnetic material, the degree of freedom in designing the thrust bearing and the support plate can be increased. Furthermore, in the configuration shown in FIG. 7, when the gap between the magnet 9 and the base plate 5 changes depending on the location, the attraction force varies depending on the location, which acts as a large couple force on the bearing and causes shaft deflection. However, according to the configuration of the above embodiment, it hardly acts as a couple.

4 and 5 show another embodiment of the present invention, respectively. In FIG. 4, 20 is a base plate, 21 is a stationary shaft made of a ferromagnetic material that is erected on the base plate, 22 is a cylindrical rotary bearing made of a ferromagnetic material, 23 is a hub made of the same material, and 24 is an axial direction. A thrust bearing composed of a magnet magnetized in the above, 25 is a yoke made of a ferromagnetic material, 26 is a driving magnet provided on the outer surface of the hub, 27 is a driving coil, 28 is a stator yoke, and 29 is a sealing magnet. is there.

In the embodiment of FIG. 5, the fixed shaft 21 is provided on the hub 23, and the yoke 25 for supporting the thrust bearing 24 is attached to the base 20. The other structure is almost the same as that of FIG. FIG. 6 shows a magnetic circuit formed by the thrust bearing 24, the bearing 22, and the shaft 21.

In the structure of the bearing device, as shown in FIG. 3, a magnetic circuit indicated by an arrow is formed by the shaft 21, the cylindrical bearing 22, the yoke 25, and the thrust bearing 24, and the shaft 21 and the magnet are connected to each other. The thrust bearing 24 is adsorbed and held.

Even in the case of the above configuration, a large attraction force can be obtained with a small magnet (thrust bearing) as in the embodiment of FIGS. Also, the attractive force of the magnet does not act as a couple.

[0019]

[Effect of device]

 As described above, according to the present invention, since the rotary shaft and the thrust bearing composed of the magnet are in direct contact with each other, a small magnet can provide a high attraction force in the thrust direction, and the shaft shaft It is possible to fix the direction.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a bearing device according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a bearing device showing another embodiment.

FIG. 3 is a plan view of a thrust bearing.

FIG. 4 is a sectional view of a bearing device according to another embodiment of the present invention.

FIG. 5 is a sectional view of a bearing device according to another embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a magnetic circuit of the bearing device.

FIG. 7 is a sectional view of a conventional bearing device.

[Explanation of symbols]

 1 rotating shaft 2 cylindrical bearing 3 thrust bearing 4 hub 5 base plate 6 driving magnet 7 stator core 8 driving coil 9 magnet mounted on the outside of hub 10 thrust bearing made of magnet 11 base plate 13 spacer 14 dynamic pressure generating groove 20 Base 21 Fixed Shaft 22 Cylindrical Rotating Bearing 23 Hub 24 Thrust Bearing Consisting of Magnet 25 Yoke 26 Drive Magnet 27 Drive Coil 28 Stator Yoke 29 Sealing Magnet

Claims (1)

[Scope of utility model registration request] 1. A shaft and a cylindrical bearing for supporting the shaft,
A bearing device comprising a thrust bearing, characterized in that the thrust bearing is composed of an axially magnetized magnet, and the thrust bearing is supported by a base plate that closes a cylindrical bearing. .