JPH0630524U - Bearing device - Google Patents

Abstract

(57) [Abstract] [Purpose] Strengthening the magnetic force of the magnet surface to the magnetic fluid of the thrust bearing makes it easier to hold the magnetic fluid on the thrust surface and improves the lubrication performance. [Structure] The rotating shaft 11 supports a cylindrical bearing 12, and the thrust bearing 13 made of a magnet has a magnet surface supporting the shaft, that is, a magnet surface facing the magnetic fluid 16 is multi-pole magnetized. The thrust bearing 13 is supported by the support plate 15. In addition, a thin spacer 14 made of a ferromagnetic material is interposed in the middle in order to enhance wear resistance as required. [Effect] When the magnet surface of the thrust bearing is formed with multi-pole magnetization, the magnetic flux density increases at the boundary between the N pole and the S pole,
It becomes easier to hold the magnetic fluid. Therefore, since the magnetic fluid can be uniformly held on the thrust surface, the lubricating performance is improved.

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, as a bearing device for this type of motor, the bearing device shown in FIG. 7 is known. In the figure, 1 is a base, 2 is a shaft standing on the base, 3 is a cylindrical radial bearing, 4 is a hub supporting a radial bearing, 5 is a drive magnet, 6 is a drive coil, Reference numeral 7 is a yoke, 8 is a thrust bearing composed of a magnet attached to the hub side, 9 is a thrust bearing support plate, and 10 is a magnetic fluid serving as a lubricant.

According to the configuration of the bearing device described above, since a closed magnetic circuit is formed between the thrust bearing made of a magnet and the shaft, the magnetic fluid is reliably retained and the lubricant is always supplied to the thrust surface. Be kept in good condition.

[0004]

[Problems to be solved by the device]

 However, in the bearing device having the above-mentioned configuration, there is a problem in the strength of the magnetic force of the thrust bearing composed of a magnet. If the strength of this magnetic force is small, the suction force for holding the magnetic fluid is weak and the thrust surface Lubrication performance cannot be fully exerted. Further, if the suction force to the magnetic fluid is weak, the magnetic fluid easily leaks to the outside of the device.

[0005]

[The purpose of the device]

 The present invention has been made in order to solve the above problems, and its main object is to provide a bearing device capable of significantly improving the magnetic strength of a thrust bearing composed of a magnet.

[0006]

[Means for Solving the Problems]

 According to the present invention, in a bearing device including a shaft, a cylindrical bearing supporting the shaft, and a thrust bearing including a magnet, the magnet surface of the thrust bearing facing the magnetic fluid is formed in a multi-pole magnetized form. That is the gist.

[0007]

[Action]

 As described above, when the magnet surface of the thrust bearing facing the magnetic fluid is formed with multi-pole magnetization, the magnetic flux density at the boundary between the N pole and the S pole becomes high, and the magnetic force of the entire thrust bearing is strengthened. . Therefore, the suction force for holding the magnetic fluid is increased and the lubrication performance is improved.

[0008]

【Example】

 1 and 2 show an embodiment of the present invention. In the figure, 11 is a rotating shaft, 12 is a cylindrical bearing that supports the rotating shaft, and 13 is a thrust bearing composed of a magnet. As shown in FIG. 2, this thrust bearing 13 is a magnet surface facing the shaft. Is composed of two magnetic poles, an N pole and an S pole. The thrust bearing 13 does not have to directly contact the rotating shaft, and as shown in FIG. 2, a spacer 14 made of a ferromagnetic material such as hardened steel may be interposed between the thrust bearing 13 and the thrust bearing 13 to enhance wear resistance. . As the spacer, a relatively thin non-magnetic layer, for example, a ceramic thin plate or a wear resistant coating layer may be used. Reference numeral 15 is a thrust bearing support plate, and 16 is a magnetic fluid.

As described above, when the shaft bearing magnet surface of the thrust bearing 13, that is, the magnet surface facing the magnetic fluid is composed of two magnetic poles, an N pole and an S pole, the magnetic flux at the boundary between the N pole and the S pole is formed. Higher density makes it easier to hold the magnetic fluid. Therefore, as the number of the boundaries increases, the attraction force for the magnetic fluid between the rotary shaft and the thrust bearing increases, and the magnetic fluid leakage prevention function improves. Moreover, since the magnetic fluid can be uniformly held on the thrust bearing surface, the lubricating performance is improved.

3 to 5 show examples in which the number of multi-pole magnetizations of the thrust bearing is further increased and the number of magnetic pole boundaries is increased. Further, by forming a spiral groove 17 as shown in FIG. 6 on the bearing surface of the thrust bearing 13 or the spacer 14 which supports the rotary shaft 11, it becomes a hydrodynamic bearing due to the dynamic pressure effect, and reliability against wear is improved. Get higher

[0011]

[Effect of device]

 As described above, according to the present invention, the magnet surface of the thrust bearing, which faces the magnetic fluid, is formed into a multi-pole magnetized structure, which facilitates lubrication of the thrust bearing and improves reliability against wear. The durability can be greatly improved.

[Brief description of drawings]

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

FIG. 2 is a plan view of a thrust bearing.

FIG. 3 is a plan view of a thrust bearing according to another embodiment.

FIG. 4 is a plan view of a thrust bearing according to another embodiment.

FIG. 5 is a plan view of a thrust bearing according to another embodiment.

FIG. 6 is a plan view of a thrust bearing in which a spiral groove is provided on a shaft bearing surface.

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

[Explanation of symbols]

 1 Base 2 Shaft 3 Radial Bearing 4 Hub 5 Drive Magnet 6 Drive Coil 7 Yoke 8 Thrust Bearing Consisting of Magnet 9 Thrust Bearing Support Plate 10 Magnetic Fluid 11 Rotating Shaft 12 Cylindrical Bearing 13 Multipolar Magnetized Thrust Bearing 14 Spacer 15 Support plate 16 Magnetic fluid

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 made of a magnet, wherein the magnet surface of the thrust bearing facing the magnetic fluid is formed into a multi-pole magnetized structure.