JPS6238055Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention relates to the structure of a magnetic fluid seal device used in a rotating machine.

[Prior art and its problems]

A magnetic fluid seal device is a magnetic cylinder attached to the rotating shaft of a rotating machine, such as a superconducting rotating machine, and two annular pole blocks, which are a fixed part facing the magnetic cylinder, and a magnetic fluid seal device arranged between the two annular pole blocks. By means of a magnetic circuit formed by several magnets, magnetic flux is concentrated on the minute projections provided on either the magnetic cylinder or the annular pole block, and the magnetic fluid is distributed between the rotating part and the fixed part. This is a device that has the function of sealing a vacuum or gas by holding it between the

A magnetic fluid sealing device of this type is shown in FIGS. 1 and 2. A magnetic circuit is formed by the magnet 6 between the annular microprotrusion 8 of the magnetic cylinder 3 provided on the outer periphery of the rotating shaft 2 and the annular pole block 5 of the fixed part facing the annular microprotrusion 8, and the magnetic flux of this magnetic circuit is is concentrated at the tip of the annular microprotrusion 8, and the magnetic fluid 9 is held between the pole block 5 and the annular microprotrusion 8.

An O-ring 7 is assembled between the casing 1 and the annular pole block 5, and an O-ring 4 is assembled between the magnetic cylinder 3 and the rotating shaft 2.

In addition, the magnetic fluid 9 evaporates and scatters due to the heat generated by the viscous mass due to the rotation of the annular microprotrusions 8 provided on the magnetic cylinder 3. In order to prevent this, an annular cooling channel 11 is provided in the annular pole block 5 as a means for removing the generated heat.
The cooling water channel 11 has an outlet pipe 1 provided in the casing 1.
Water is circulated from the outside via 2 for cooling.

Furthermore, in consideration of deterioration of the magnetic fluid 9, a magnetic fluid replenishment mechanism is provided. This magnetic fluid replenishment mechanism is
A magnetic fluid replenishment hole 10 is provided near the cooling water groove 11 of the annular pole block 5, and the magnetic fluid 9 is supplied to the seal portion from a magnetic fluid replenishment port 16 provided in the casing 1.

However, in the conventional magnetic fluid sealing device, since the magnetic fluid replenishment hole 10 and the cooling water channel 11 are arranged in parallel in the direction of the rotation axis, the magnetic resistance in the magnetic circuit increases, so that the required sealing performance cannot be obtained. Therefore, there is a disadvantage that the size of the magnet becomes large and the size of the entire structure becomes large.

[Purpose of invention]

An object of the present invention is to eliminate the drawbacks of the above-mentioned conventional devices and provide a miniaturized magnetic fluid sealing device.

[Example of idea]

An embodiment of the magnetic fluid seal device according to this invention will be explained with reference to FIGS. 3 and 4.

Parts corresponding to those in FIG. 1 are given the same reference numerals.
In the cross section of the magnetic fluid seal device shown in FIG. 3, the annular pole block 14 is different from the conventional annular pole block 5 in that a cooling water channel 11 is provided along the inner peripheral surface of the casing 1, and a cooling water channel is provided in a part of the circumferential direction. A part without a grooved part is formed, a magnetic fluid replenishment hole 10 is provided in this part, and the magnetic fluid 9 is supplied to the seal part from the hole 17 provided in the casing 1 through a magnetic fluid replenishment cylinder 15. .

Cooling water is supplied to the cooling water channel 11 from a cooling water inlet 12a provided in the casing 1, and is discharged from a cooling water outlet 12b. Although the cooling water channels are not provided on the entire circumference unlike in the past, the cooling effect is not a problem in practice because there is only a small portion where no cooling water channels are provided.

The magnetic fluid supply cylinder 15 is connected to the annular pole block 14 via an O-ring 13 with a screw.

In this way, the cooling water channel 11 and the magnetic fluid supply hole 10
Since they are arranged on the same circumference, it is possible to shorten the length in the direction of the rotation axis, and the magnetic resistance in the magnetic circuit of this device can be reduced, so the magnet can be made smaller and the overall size can be reduced.

[Effect of idea]

According to this invention, the cooling channel of the magnetic fluid seal device and the magnetic fluid replenishment hole are provided on the same circumference, so it is possible to shorten the rotation axis direction, and the magnetic resistance can be reduced, so the magnet can be made smaller. The effect of downsizing the overall structure of the magnetic fluid seal device can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional magnetic fluid seal device, FIG. 2 is a sectional view taken along the Y-Y line in FIG. 1, and FIG. 3 is a sectional view of an embodiment of the magnetic fluid seal device according to the present invention. , FIG. 4 shows a sectional view taken along the Z-Z line in FIG. 3. 1... Casing, 2... Rotating shaft, 3... Magnetic cylinder, 4... O ring, 6... Magnet, 7... O
Ring, 8... Annular microprotrusion, 9... Magnetic fluid,
10...Magnetic fluid supply hole, 11...Cooling water channel, 1
2...Outlet tube. 12a...Cooling water inlet, 12b...
... Cooling water outlet, 13 ... O ring, 14 ... Annular pole block, 15 ... Magnetic fluid supply cylinder, 1
6...Magnetic fluid supply port.

Claims (1)

[Scope of utility model registration request] An annular micro-protrusion for concentrating the magnetic flux generated by the magnet is provided on either one of the magnetic cylinder disposed on the outer periphery of the rotating shaft and the inner circumferential surface of the stationary pole block surrounding the magnetic cylinder, and this annular micro-protrusion In a device that seals a vacuum or gas with a magnetic fluid injected into the annular pole block, a cooling channel is provided along the inner peripheral surface of the casing, and a part of the circumferential direction is not grooved,
A magnetic fluid supply hole is provided in this part on the same circumference,
A magnetic fluid sealing device characterized in that a magnetic fluid replenishment cylinder is passed through a hole provided on the outer periphery of a casing and connected to a magnetic fluid replenishment hole to replenish magnetic fluid.