JP2008202585A - Rotary device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a turbo-rotary device in which a rotating shaft properly seals a seal part in a through hole extending through a partition wall to prevent an oil mist from flowing into a compression chamber. <P>SOLUTION: A spiral groove 4MD on the lower side at the seal part S biases the gas at the seal part S to a bearing chamber M side. The rise of the oil mist from the bearing chamber M is suppressed, therefore, since a pressure difference in the seal part S is secured while the evacuation amount of the bearing chamber M is reduced. The stagnation of the oil by the surface tension is also obstructed. Since a communication passage 8P communicating with the bearing chamber M side is formed on the fixed side, the communication passage 8P functions as a bypass passage, and a gas flow equal to a difference between the recirculation amount from the communication passage 8P and the biased amount by the spiral groove 4MD is produced and the flow of the gas toward the bearing chamber M is fixed in quantity. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a turbo rotating device that can be applied to, for example, a blower or a centrifugal separator as an electric compressor for gas circulation in a gas laser oscillator device.

  For example, in the case of a flow type carbon dioxide gas laser oscillator device, it is compressed while flowing a mixed gas of carbon dioxide gas and other gas and supplied to the laser oscillator to resonate, and a gas circulation circuit is configured in the device. Yes. As a blower as one element in the configuration of the circulation circuit, a turbo-type rotating device that rotates a turbo blade at high speed to compress gas and supplies the gas to a laser oscillator is used. The background art will be described below by taking this turbo rotating device as an example.

  In this type of turbo rotating device, a turbo blade is rotatably disposed in the upper part of the housing, and a mechanism for compressing and discharging the gas is provided, and the turbo blade (rotor) is rotated at a high speed below. A rotational drive source (for example, an electric motor, hereinafter abbreviated as a motor) is provided. The rotating body including the rotor of the motor, the turbo blade, the rotating shaft, and the like is pivotally supported by a mechanical bearing and is provided with lubricating means using oil. (See Patent Document 1).

  The configuration of this turbo rotating device is as shown in FIG. FIG. 5 is a longitudinal sectional view schematically showing a rotational drive source motor 2 in which a turbo blade 7 is rotatably arranged inside the housing 1 and is rotated at a high speed below the turbo blade 7. Are arranged, and both are connected by a rotating shaft 4. The motor 2 is composed of an electrode coil 2K fixed on the housing 1 side and a rotor 2M fixed to the rotary shaft 4 corresponding to the electrode coil 2K. Electric energy is supplied to the electrode coil 2K from the inverter 3. Is supplied.

The rotating shaft 4 is rotatably held with respect to the housing 1 via an upper bearing 5 and a lower bearing 6. A turbo blade 7 is fixed to an attachment shaft 4 </ b> S formed above the rotating shaft 4. Yes. A rotating body including the motor 2, the rotor 2M, and the rotating shaft 4 is held by an upper bearing 5 and a lower bearing 6 that constitute a bearing mechanism. The upper bearing 5 and the lower bearing 6 are disposed in the bearing chamber M. When the turbo blade 7 is driven to rotate at high speed by the motor 2, the gas is sucked from the inlet 1K, compressed, and exhausted 1H. More discharged. The intake port 1K to the exhaust port 1H form a compression chamber C that performs gas compression. The gas from the exhaust port 1H is supplied to a laser oscillator (not shown) through a gas circulation circuit (not shown) as described above.

  As shown in FIG. 5, the rotary shaft 4 has a hollow hole 4H formed on the shaft center. The lower part of the hollow hole 4H has a tapered shape with the inner hole expanding upward, and the lower part is It is immersed in the oil L for lubrication. Accordingly, the lubricating oil L entering the lower region of the hollow hole 4H moves upward in the hollow hole 4H under the action of the centrifugal force caused by the rotation of the rotary shaft 4, and this action causes the hollow hole 4H to move upward. 4H causes the pump function. Thus, the lubricating oil L is sequentially sent upward and discharged outward from the injection hole 4T to cool the motor 2 and lubricate the upper bearing 5 and the lower bearing 6. The lubricating oil L that has been lubricated and cooled is again stored in the lower oil tank 1Y, sucked up again, and circulated.

  In this way, the lubricating oil L circulates to lubricate the upper bearing 5 and the lower bearing 6. By this lubrication, particularly in the bearing chamber M, the sprayed oil L (oil mist) exists and floats. It will be. The presence of the spray-like oil L in the bearing chamber M improves the lubrication in the upper bearing 5 and the lower bearing 6. However, when this oil mist flows into the compression chamber C, it flows into the laser oscillator and the like, and the laser oscillation function. Reduce.

  For this reason, the compression chamber C and the bearing chamber M are blocked by the partition wall 8 made of a member integral with the housing 1 or the housing 1. That is, the housing 1 is provided with a through hole 8A through which the rotary shaft 4 can pass without contact at a position above the upper bearing 5, and a seal portion S is formed in cooperation with the rotary shaft 4. For example, a labyrinth seal or the like is applied to the seal portion S although not shown. In the seal portion S, the gap between the rotating shaft 4 and the penetrating portion is usually set to several tens of microns. In addition to the labyrinth seal, a gas seal set to a small parallel gap of several tens of microns is also employed. In addition, 9 is a bearing holding member and 9H is a through-hole.

  As described above, in the turbo type rotating device used for the laser oscillator, the existence and countermeasure of the mist (gas) of the oil L are important, but the existence of the oil L that is the generation source of the mist cannot be ignored. In particular, it is necessary to prevent the oil L discharged from the injection hole 4T of the rotating shaft 4 from reaching the upper seal portion S as much as possible. For this purpose, as will be described later, a device has been proposed in which means for energizing the gas flow is provided in the seal portion S. This device is shown in FIG.

  That is, FIG. 4 is a turbo type rotating device in FIG. 5 in which a spiral groove 4M is provided at a portion where the rotating shaft 4 penetrates the through hole. Details of this spiral groove are shown in FIG. The spiral groove 4M forms a fluid energizing region AE for energizing the flow of fluid from the compression chamber C to the bearing chamber M. Specifically, when the rotary shaft 4 is rotationally driven in the direction of the arrow, the fluid at the groove interval of the spiral groove 4M moves downward. That is, the spiral groove 4M is a spiral groove that urges a fluid containing gas toward the bearing chamber M side.

In this way, the gas containing oil mist is prevented from flowing into the compression chamber C side. 3 and 4, the components denoted by the same reference numerals as those in FIG. 5 are the same as those in FIG. 5 and have the same functions, and detailed description of the operation of these components is omitted.
The seal portion S and the bearing holding member 9 are fixed to the housing 1 via bolts 11 shown in FIG.
Japanese Unexamined Patent Publication No. 2000-209815 (page 1-3, FIGS. 1-8)

  The sealing mechanism of the partition wall 8 that partitions the compression chamber C and the bearing chamber M has the following problems. First, in the labyrinth seal method, concentricity of the through hole 8A with respect to the rotating shaft 4 side is strongly demanded in order to prevent contact between the through hole 8A side of the partition wall 8 and the rotating shaft 4 due to vibration of the rotating body during operation. Although it is severe, it is not easy to confirm and adjust the concentricity when assembling turbo rotating equipment. In addition, when determining by fitting accuracy between parts, the required values of concentricity and machining accuracy of a plurality of parts concerned become severe, and on the other hand, a limit is set for reducing the gap.

  Therefore, when the gap is widened, the amount of vacuuming of the seal portion S in operation increases, and when used as a blower of a laser oscillator, the amount of laser gas consumed increases and the running cost increases. Further, when this seal mechanism is constituted by a labyrinth seal, the machining is complicated, and machining a part of the rotating shaft 4 is a problem in terms of cost and operation, and must be a separate part. It is a fact. On the other hand, the spiral groove method has a problem that gas consumption increases (running cost increases) due to the excellent ability of the spiral groove.

  In order to solve the above problems, a turbo-type rotating device provided by the present invention is a part that penetrates the partition walls of the compression chamber and the bearing chamber, and the outer peripheral surface of the rotating shaft and the through hole at a position below the intermediate part of the through hole. A spiral groove is formed between the inner peripheral surface and a communication passage that connects the inner peripheral surface of the through hole and the bearing chamber side is provided in the partition wall.

  The turbo type rotating device provided secondly by the present invention is formed such that the direction of the spiral groove urges the gas urging downward through the through hole. Therefore, the differential pressure fluctuation can be reduced.

  Furthermore, the turbo rotating device provided by the present invention thirdly has a spiral groove formed on the inner peripheral surface of the through hole, and the configuration is simplified. Furthermore, the fourth aspect of the present invention provides a turbo type rotating device in which a filter for trapping a lubricating fluid is provided on the bearing chamber side of the communication path, and the flow of the fluid energized region oil mist can be prevented and gas can be prevented. Since the gas flows through the communication path, the gas energizing function is guaranteed.

  It is possible to prevent oil from staying in the seal and further preventing oil that has entered the seal from filling the seal. Further, since the oil is urged downward, the oil does not flow backward in the direction of the compression chamber C. That is, the amount of vacuum exhaust can be reduced.

A first feature of the present invention is a configuration in which a spiral groove is formed only between a through hole in a portion of a through hole through which the rotating shaft passes through the partition wall and an outer periphery of the rotating shaft and below the intermediate portion of the through hole. This is the point. Moreover, the spiral groove urges the fluid downward by the rotation of the rotating shaft. Furthermore, the second feature of the present invention is that a communication passage for communicating the seal portion formed by the spiral groove and the bearing chamber is provided together, and a filter is attached to the bearing chamber side opening of the communication passage. Is the third feature.
Therefore, the best mode of the present invention is a turbo-type rotating device having both of these characteristics.

This embodiment is shown in FIG. FIG. 1 is an enlarged cross-sectional view showing a portion where the rotary shaft 4 penetrates the partition wall 8. In FIG. 1, parts denoted by the same reference numerals as those in FIG. 3 have the same functions as the reference numerals in FIG. Detailed description of these reference numerals will be omitted.
In FIG. 1, reference numeral 8 </ b> P is a communication passage formed in the partition wall 8, and a filter F is installed at the opening to the bearing chamber M. The other opening corresponds to the upper end portion of the spiral groove 4MD.

  At the site of the spiral groove 4MD, the sealing mechanism works effectively by the spiral, and the amount of gas flowing from the compression chamber C by cooperation with the seal portion S in which the spiral groove is not formed only by the rotating shaft 4 at the site of the through hole 8A. Corresponds to the difference between the vacuum exhaust amount from the bearing chamber M and the gas flow rate recirculated from the communication passage 8P. This is a bypass flow path by providing the communication path 8P communicating from the bearing chamber M side on the stationary side, and even when the downward gas flow becomes excessive due to the spiral groove effect, the gas bypass flow from the communication path 8P Thus, the gas flow rate downward from the compression chamber C is quantified, and the backflow of oil to the upper surface of the seal portion S can be prevented.

  With the above function, when the turbo rotating device operates as a gas compressor, the downward gas flow is urged in the fluid energizing region AE by the rotation of the spiral groove 4MD in the seal portion S. In this case, the rotating shaft peripheral surface portion 4F above the through hole portion where the spiral groove 4MD is not formed functions to guide the downward flow of the fluid as described later. As a result, the oil mist is prevented from flowing into the compression chamber. The oil that has entered before the turbo type rotating device is started is scraped out in the bearing chamber M. Then, gas is actively generated downward by the spiral groove 4MD, so that it is provided on the stationary side via the communication passage 8P that passes through the spiral groove and communicates from the bearing chamber, that is, the bearing chamber M side via the communication passage 8P. The oil that has entered the communication path 8P from the bearing chamber M into the seal portion S where the spiral groove 4MD is present is actively caused to flow downward by the presence of the spiral groove 4MD. With this function, the oil that has flowed into the seal portion S through the communication path 8P can be prevented from flowing into the compression chamber C, and the overall gas consumption can be suppressed by supplying gas from the communication path 8P.

  From this, when the exhaust pipe R is provided in the lower part of the bearing chamber M as shown in FIGS. 4 and 5, the gas vacuum exhaust flow rate during operation can be controlled. This leads to a reduction in running cost. In the gap of the seal portion S, it is extremely difficult to allow only gas to pass and trap oil mist, but it is easy to provide an oil trap in the communication path in the stationary side that communicates from the bearing chamber M or in the lower part. Only gas can be passed and oil trapped.

  Therefore, oil can be prevented from entering the seal portion S through the communication path 8P. In the spiral groove 4MD, the rotation of the oil causes the oil in the spiral groove 4MD to sequentially move in the circumferential direction, thereby preventing the oil from staying due to the surface tension. FIG. 2 shows an example in which a spiral groove 8MD is provided in the region below the middle on the inner peripheral surface side of the through hole 8A, and the function is the same as FIG.

  The features of the turbo rotating device provided by the present invention are as described in detail above, but are not limited to the above and illustrated examples. In particular, the shape of the communication path 8P does not necessarily have to be L-shaped as in the illustrated example. For example, both openings in the illustrated example can be connected by a straight line. Furthermore, one L-shaped communication path 8P can be provided on each of both sides. The present invention includes all of these modifications.

It is a longitudinal cross-sectional view which shows the structure of the principal part of the turbo type rotating apparatus which this invention provides. It is a longitudinal cross-sectional view which shows the structure of the principal part of the turbo type rotating apparatus which this invention provides. It is a longitudinal cross-sectional view which expands and shows the principal part of the turbo type rotating apparatus which this invention provides. It is a figure which shows the structure which added the improvement to the rotating shaft which is the attachment part of the turbo blade of the conventional turbo type rotary apparatus. It is a figure which shows schematically the structure of the conventional turbo type | mold rotary apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing 1K Inlet 1H Exhaust 1Y Oil tank 2 Motor 2K Electrode coil 2M Rotor 3 Inverter 4 Rotating shaft 4F Rotating shaft peripheral surface 4H Hollow hole 4M Spiral groove 4MD Spiral groove 4S Mounting shaft 4T Injection hole 5 Upper bearing 6 Lower bearing 7 Turbo blade 8 Bulkhead 8A Through hole 8MD Spiral groove 8P Communication passage 9 Bearing holding member 9H Through hole 11 Bolt AE Fluid energizing region C Compression chamber F Filter L Oil M Bearing chamber S Seal portion R Exhaust pipe

Claims (3)

  A compression chamber in which a rotating body for compressing gas by rotation is installed, a rotary drive source for rotating the rotary body, a rotary shaft for connecting the rotary body and the rotary drive source, and a drive system such as a bearing are installed. A bearing chamber is provided, the compression chamber and the bearing chamber are partitioned by a partition, and a housing having a through-hole through which the rotation shaft is inserted is provided in the partition, and the rotating body is rotated to rotate the rotating body. In the rotating device that performs the compression function, the fluid in the through hole is urged toward the lower side of the through hole between the outer peripheral surface of the rotation shaft and the inner peripheral surface of the through hole in the lower part of the intermediate part of the through hole. A rotating device characterized in that a spiral groove is provided, and a communication path that connects the inner peripheral surface of the through hole and the bearing chamber side is provided in the partition wall.   The rotating device according to claim 1, wherein the spiral groove is formed on an inner peripheral surface of a through hole formed in the partition wall. The rotating device according to claim 1 or 2, wherein a filter for trapping the lubricating fluid is provided in the bearing chamber side opening of the communication path.

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