JPH0536125U - Magnetic fluid thrust bearing device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a magnetic fluid bearing device for a rotary machine, which prevents lubricant from leaking from the bearing portion, has excellent long-term reliability, and is maintenance-free. According to a magnetic fluid thrust bearing device of the present invention, a rotary plate 1 having a suction type spiral groove 5 is mounted on a rotary shaft 3, and the rotary plate 1 is sandwiched between the rotary plate 1 and a predetermined gap 11. The bearing 4 having the permanent magnet 16 on the outer peripheral side and the tooth portion 17 and the inner peripheral groove 14 on the inner peripheral side is mounted on the bearing bracket 7 and is formed by the bearing 4, the rotary plate 1, and the rotary shaft 3. The magnetic fluid circulation device is characterized in that the space is filled with the magnetic fluid 13, and the magnetic fluid 13 is discharged from the inner peripheral side of the bearing 4 and returned to the outer peripheral side thereof, which is composed of a pump 8 and a pipe 15.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a magnetic fluid bearing device for preventing leakage of a lubricant of a bearing in a rotary machine.

[0002]

[Prior Art]

 In recent years, as environmental pollution prevention regulations have become stricter in each technical field, measures to prevent leakage of bearing lubricants of various rotary machines have been emphasized. In addition, there are strong demands for long-term reliability and maintenance-free for various rotary machines installed in nuclear power plants (such as induction motors).

Leakage of the lubricant from the bearing portion not only leads to environmental pollution, but also deteriorates the bearing performance due to lack of the lubricant and deteriorates the insulator (coil coating etc.) due to leakage into the rotating machine. In addition, it may cause insulation breakdown, which is a major cause of accidents. Next, the related art will be described with reference to typical examples of the related art.

FIG. 2 is a cross-sectional view of a conventional thrust bearing used in a high speed rotating machine or the like. The rotating plate 1 is fixed to the rotating shaft 3 by a fixing ring 2 and is arranged so as to be sandwiched by bearings 4. The rotary plate 1 is provided with a spiral groove 5 as shown in FIG. 3, and a bearing effect is produced by rotating in the direction of the arrow in the drawing. The spiral groove 5 shown in the figure is called a suction type, and the lubricant 6a flows from the outer circumference to the inner circumference. The lubricant 6a in the bearing bracket 7 is supplied to the sliding surface (bearing gap) by the pump 8 installed outside, and is cooled by the cooler 9 as necessary. On the other hand, a labyrinth seal 10 is provided so that the lubricant 6b discharged from the bearing 4 does not leak inside or outside the machine.

[0005]

A lubricating film is formed in the bearing gap 11 by the dynamic (pump) action of the rotary plate 1, and a film pressure 12 as shown in FIG. 4 is generated. Due to the radial film pressure distribution, the lubricant 6b is ejected from the inner peripheral portion of the bearing along the surfaces of the rotary plate 1 and the rotary shaft 3 and easily reaches the labyrinth seal 10. Therefore, there is a considerable risk that the lubricant 6b will be discharged into and out of the machine during operation. As a result, the insulation of the stator coil deteriorates inside the machine, and in the case of leakage outside the machine, it causes environmental pollution.

The present invention has been made in view of the above-mentioned problems of the prior art. It completely prevents the lubricant from leaking from the bearing portion, has long-term reliability, and is maintenance-free for rotary machines. An object is to provide a magnetic fluid bearing device.

[0007]

[Means for Solving the Problems]

 In order to solve the above problems, in the present invention, a non-magnetic rotating plate mounted on a rotating shaft and having a suction-type spiral groove, and a rotating plate sandwiching the rotating plate with a predetermined gap therebetween are provided. The bearing has a permanent magnet on the outer peripheral side and a plurality of teeth on the inner peripheral side, the magnetic fluid filled in the gap, and the magnetic fluid is discharged from the inner peripheral side of the bearing and returned to the outer peripheral side. And a magnetic fluid circulation device that operates.

[0008]

[Action]

 The present invention is configured as described above, and the load in the axial direction is supported by the suction type grooved bearing that sucks the magnetic fluid as the lubricant from the outer peripheral portion of the bearing, and the magnetic fluid seal composed of the magnetic fluid and the permanent magnet. The equipment provides a perfect lubricant seal.

[0009]

【Example】

 FIG. 1 is a cross-sectional view showing an embodiment of the present invention, and the parts described in the prior art of FIG.

The present embodiment is a bearing device in which a suction type spiral groove 5 is provided on the rotary plate 1 side as shown in FIGS. 1 and 3. The rotation direction of the rotary plate 1 is as shown by the arrow in FIG. 3, and by rotating in this direction, it acts as a suction type thrust bearing with a spiral groove. The magnetic fluid 13 is constantly filled inside and outside the bearing. Further, a bearing inner peripheral groove 14 is provided in the inner peripheral portion of the bearing 4, the magnetic fluid 13 is discharged therein, and the groove 14 is connected to the outside by a pipe 15. The rotating plate 1 is made of a non-magnetic material for the reason described later. A permanent magnet 16 is arranged on the outer peripheral side of the bearing 4, and a plurality of teeth 17 are provided on the inner peripheral side.

A pump 8 and, if necessary, a cooler 9 are provided in the pipe 15 connected to the bearing inner peripheral groove 14, and the magnetic fluid 13 is returned to the outer peripheral portion of the bearing 4. Further, a magnetic fluid film 18 is formed at the tip of the tooth 17. Next, the operation will be described.

When the rotary plate 1 rotates, the magnetic fluid 13 near the outer peripheral portion of the bearing 4 is sucked by the pump effect, and the lubricating film pressure 12 as shown in FIG. 4 is generated in the bearing gap 11. After passing through the bearing gap 11, the magnetic fluid 13 is discharged into the bearing inner circumferential groove 14 and guided to the pipe 15 by the pump 8. The magnetic fluid 13 cooled by the cooler 9 is returned to the outer peripheral portion of the bearing 4 again. In this way, the magnetic fluid 13 circulates and functions as a lubricant.

On the other hand, in order to prevent the magnetic fluid 13 from leaking from the bearing 4, a tooth 17 and a permanent magnet 16 are provided on the inner circumference of the bearing 4 and on the outer circumference of the bearing 4 to provide a magnetic fluid seal mechanism. ing. A magnetic circuit as shown by the broken line in FIG. 1 is generated by the permanent magnet 16. At this time, as described above, the material of the rotary plate 1 must be non-magnetic, and if it is a magnetic material, the bearing gap 11 is smaller than the labyrinth gap, so the magnetic circuit is not as shown. No With the magnetic circuit as shown in the figure, the magnetic fluid film 18 is reliably formed in the gap between the tooth 17 and the rotating shaft 3, and the perfect sealing function can be maintained.

With the above operation, not only a stable lubrication performance is obtained, but also by providing a magnetic fluid seal mechanism using magnetic fluid as a lubricant, it is possible to prevent the lubricant from leaking into and out of the machine.

[0015]

[Effect of the device]

 According to the present invention, it is possible to completely seal the leakage of the lubricant from the bearing portion and to obtain a sufficient lubrication performance in a wide range from the stopped state to the high speed operation region. As a result, the bearing performance is reduced and environmental pollution is improved, and it becomes a maintenance-free bearing device with excellent long-term reliability, and it is possible to provide a rotating machine with high performance and excellent long-term reliability.

[Brief description of drawings]

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

FIG. 2 is a sectional view for explaining a conventional technique.

FIG. 3 is an explanatory view showing a spiral groove provided in the rotary plate 1.

FIG. 4 is an explanatory view showing a pressure distribution generated in a radial direction of a rotating plate.

[Explanation of symbols]

 1 ... Rotating plate 10 ... Labyrinth 2 ... Fixing ring 11 ... Bearing gap 3 ... Rotating shaft 12 ... Pressure distribution 4 ... Bearing 13 ... Magnetic fluid 5 ... Spiral groove 14 ... Bearing inner circumferential groove 6a, 6b ... Lubricant 15 ... Piping 7 ... Bearing bracket 16 ... Permanent magnet 8 ... Pump 17 ... Teeth 9 ... Cooler 18 ... Magnetic fluid film

Claims (1)

[Scope of utility model registration request] 1. A non-magnetic rotary plate mounted on a rotary shaft and having a suction-type spiral groove, and a permanent magnet provided on the outer peripheral side so as to sandwich the rotary plate with a predetermined gap from the rotary plate. A bearing having a plurality of teeth on the inner peripheral side; a magnetic fluid filled in the gap; and a magnetic fluid circulating device for discharging the magnetic fluid from the inner peripheral side of the bearing and returning it to the outer peripheral side. Characteristic magnetic fluid thrust bearing device.