JPS5936563A - Rotating body device - Google Patents

Abstract

PURPOSE:To prevent occurrence of vibration which is apt to occur in low speed rotation by connecting plural positions in circumferential direction of an annular atmospheric layer to each other outside of the annular atmosphere. CONSTITUTION:Holes 12a-12c that connect an annular opening 10 formed between a cylindrical body 9 placed concentrically to a rotating body 3 and an annular opening 11 formed between outer face of the cylindrical body 9 and side wall 7 of the container are provided. Consequently, even when pressure in the opening 10 becomes locally high by deviation of axis center of the rotating body 3, the pressure is released to the part of low pressure atmosphere, and occurrence of unstable vibration can be suppressed effectively.

Description

[Detailed Description of the Invention] [Technology of the Invention Minute Hand] The present invention relates to a rotating body device, and particularly to a rotating body device that operates a rotating body in a pressure atmosphere that changes depending on the rotational speed of the rotating body. Regarding improvements.

[Technical background of the invention]

In situations where a rotating body is rotated at high speed, a method is generally adopted in which the atmosphere around the rotating body is reduced in pressure to reduce windage loss due to rotation. As means for lowering the pressure of the atmosphere around the rotating body in this way, two methods are being considered: one method is to provide a special exhaust system to lower the pressure, and the other is a method where the pressure is lowered using the rotation of the rotary body itself.

By the way, a molecular pump is usually used as a means for lowering the pressure of the surrounding atmosphere by utilizing the rotation of the rotating body itself. That is, in general, a rotating body device using a molecular pump as described above is provided with a rotating body concentrically with the container in a cylindrical container with a bottom, and a rotary body is provided on the inner surface of the side wall located near the opening of the container. A friend molecule I ring is provided with a threaded groove in close opposition to the outer circumferential surface of the rotating body main body.

In a rotating body device having such a configuration, when the rotating body starts rotating, the gas existing between the rotating body and the molecular pump changes in the direction of rotation of the rotating body due to a viscous effect. The rotational force in the same direction is discharged out of the container along the thread groove of the molecular pump. The above discharge effect increases as the rotation speed increases. Therefore, as the rotation speed increases, the pressure of the gas existing between the outer circumferential surface of the rotating body and the container decreases, and this causes the air around the rotating body to decrease. is reduced to low pressure.

In a rotating body device configured as described above, the balance of the rotating body and the performance of the molecular bonder are usually set so as to obtain the most stable rotation under the rated rotational speed.

[Problems with background technology]

In the rL-order rotating body device configured as described above, if the rotational speed of the rotating body body decreases due to overload, or if it is intentionally operated at a rotation speed lower than the normal rotation speed, the above-mentioned Since the effect of discharging gas by the molecular pump becomes smaller, the pressure between the outer circumferential surface of the rotating body body and the container inevitably becomes higher than that under the rated rotation speed.

As described above, when the pressure of the atmospheric layer is high, the conventional rotating body apparatus has a problem in that the rotating body is likely to cause unstable vibration in the horizontal direction, similar to oil whip in a journal bearing apparatus. In particular, in the case of a rotating body that is supported softly at both ends, the above-mentioned vibrations are likely to occur, which can lead to a decline in the performance of the rotating body device, accelerate wear on the bearings, and shorten the life of the entire device. There were concerns that it would be shortened.

[Purpose of the invention]

The present invention was conceived in view of the above circumstances, and its purpose is to improve the performance of a rotating body operated in an atmosphere where the pressure changes depending on the rotational speed, by simply adding simple elements. It is an object of the present invention to provide a rotating body device that can suppress the occurrence of vibrations that tend to occur at low rotational speeds, thereby improving performance and extending the lifespan.

[Summary of the invention]

The rotating body device of the present invention surrounds the outer peripheral surface of the rotating body body with a substantially constant thickness, and the pressure changes in accordance with the rotation speed of the rotating body body at a plurality of locations in the circumferential direction of the annular atmosphere layer. The feature is that a communication path is provided to communicate with each other.

〔Effect of the invention〕

As described above, a plurality of locations in the circumferential direction of the annular atmosphere layer surrounding the rotating body main body are communicated with each other outside the atmosphere layer. Therefore, when the rotating body is rotating,
A region of high pressure is locally formed in the annular atmosphere layer.
Even if the gas in the above region flows through the communication path to the region with lower pressure, the vector sum of the dynamic pressure applied to the outer peripheral surface of the rotating body becomes almost zero in any case. . Therefore, even if the average pressure of the annular atmosphere layer surrounding the outer periphery of the rotor body fluctuates as the rotational speed changes, unstable vibrations of the rotor body can be suppressed. I can do it.

In this way, it is possible to suppress the occurrence of unstable vibrations in the rotating body body, thereby preventing the deterioration of the performance of the rotating body device and shortening the life due to wear of the bearing part, thereby improving the rotational performance and increasing the lifespan. I can do it.

[Embodiments of the invention]

FIG. 1 is a schematic diagram showing an embodiment in which the present invention is applied to a vertical rotating body device.

This rotary body device J can be roughly divided into a bottomed cylindrical container 2 provided with an opening facing upward and an axis parallel to the direction of gravity, and a container 2 inside the container 2. a vertical cylindrical rotating body 3 arranged concentrically with the
A lid 4 that covers the opening of the container 2, a magnetic bearing 5 provided between the lid 4 and the rotating body 3, and a magnetic bearing 5 that faces the upper part of the outer peripheral surface 6 of the rotating body S. a molecular pump 8 fixed to the inner circumferential surface of the side wall 7 of the container 2; a cylindrical body 9 whose upper end is fixed to the molecular pump 8 and arranged concentrically with the rotating body 3; An annular gap 10 formed between the inner surface and the outer circumferential surface 6 of the rotating body main body 3
, an annular gap 1 formed between the outer surface of the cylindrical body 9 and the side wall 7 of the container 2, and an annular gap 1 formed at equal intervals in the circumferential direction of the cylindrical body 9, and the gaps 10 and 11. For example, three holes 12m, 111b, 12 that communicate with
It is composed of c.

Note that the lid body 4 is provided with an exhaust port 13. Furthermore, the power source that applies rotational force to the rotating body main body is omitted in the figure.

FIG. 2 shows the above-mentioned hole 12a of the rotating body device J of FIG.
12b and 12c are provided at the -A position, and the side wall 7 of the container 2, the cylindrical body 92 and the rotating body 3
and hole 12a.

The relative positions of 12b and 12c are shown.

With the above configuration, when the rotary body 3 starts rotating, the annular gap 10 and the gap 11 formed between the outer circumferential surface 6 of the rotary body 3 and the inner surface of the cylindrical body 9 are A gas is supplied to the lid body 4 by a molecular pump 8.
The pressure inside the gaps 10 and I1 decreases. In other words, the rotating body 3 rotates while being surrounded by an annular atmosphere layer having a pressure corresponding to the rotational speed of the rotating body 3.

Here, the annular atmosphere layer with a constant thickness existing in the gap 10 between the inner surface of the cylindrical body 9 and the outer circumferential surface 6 of the rotary body 3 is
Three holes 1 are provided in the cylindrical body 9 at three locations in the circumferential direction.
2a, 12b, 12c and the gap 11, they communicate with each other. Therefore, even if the pressure within the gap 10 locally becomes high in a portion where the axial center line of the rotary body 3 is shifted in the horizontal direction, the high pressure component and gap 1
1 to other low pressure atmosphere parts.

In addition, it is possible to effectively suppress the occurrence of unstable vibrations that tend to occur in the rotating body main body 3 due to the occurrence of localized high-pressure parts when the rotational speed is low.

In this way, it is possible to suppress the occurrence of unstable vibrations in the rotor main body 3, thereby preventing a decrease in the performance of the rotor device 1 and a shortened life due to wear of the lower bearing portion of the rotor main body 3, thereby stabilizing the rotation. This can improve performance and extend life.

Note that the present invention is not limited to the embodiments described above. In the embodiment, as means for forming a communication path, a cylindrical body 9 is provided so as to surround the outer peripheral surface 6 of the rotating body main body 1, and holes 12a, 12b, and 12cv are provided in this cylindrical body 9. 9, by installing a plurality of plate members having a curvature with a gap between them so as to surround the outer circumferential surface 6 of the rotating body main body 3, the gap and the plate members and the side wall 7 of the container 2 can be A communication path may be formed in the gap between them.

Furthermore, instead of providing the cylindrical body 9t, the side 1 of the container 2
17 may be provided with a plurality of holes in the circumferential direction, and piping that communicates between the plurality of holes may be arranged on the outside of the side wall r.

Further, the number of holes provided in the cylindrical body 9t or the side wall 7 is not limited to three, and may be provided in multiple stages in the axial direction.

Furthermore, the present invention can also be applied to a section of a horizontal rotating body.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a schematic configuration of a rotating body device according to an embodiment of the present invention, and FIG. 2 is a cutaway view taken at the loop 4 position in FIG. 1. J... Rotating body device, 2... Container, 3... Rotating body body, 4... Lid, 5... Magnetic bearing, 8... Molecular pump, 9... Cylindrical body, 10, 11...Gap, J
:la, 11b. 12c...hole, 13...exhaust port. Applicant's agent Patent attorney Takehiko Suzue 1st x 2nd x ID

Claims (4)

[Claims] (1) In a rotating body device that operates with the outer circumferential surface of the rotating body body surrounded by an annular atmosphere layer having a substantially constant thickness and whose pressure changes depending on the rotational speed of the rotating body body, the localization of the annular atmosphere layer A rotating body device characterized in that a communication path is provided to connect a plurality of locations in the direction with each other outside the annular atmosphere layer. Rotation (2) The annular atmosphere layer is formed by a cylindrical body installed in a melter housing the circuit body so as to surround the outer peripheral surface of the rotary body, and the communication path is formed in the cylindrical body. The rotating body device according to claim 1, characterized in that a plurality of holes are provided and nine gaps are formed between the body and the container. (3) The annular atmosphere layer is formed of a plurality of curvature plate members, which are installed in a container housing the rotary body so as to surround the outer peripheral surface of the rotary body with a gap between them. The rotating body device according to claim 1, wherein the communicating path is formed by the gap and a gap formed between the curvature plate material and the container. (4) The annular atmosphere layer is formed by a container that accommodates the rotating body, and the communication path includes a plurality of round holes that are cut in the side wall of the container in the circumferential direction and communicates between these holes. The rotating body device according to claim (1), characterized in that it is formed of a tube.