JP4742886B2 - Rotating equipment - Google Patents

Description

  The present invention includes a shaft that is rotatably supported by an oil-lubricated bearing in a casing having a partition wall provided with a shaft insertion hole, and that is attached to the impeller attachment portion. The present invention relates to a rotating device that houses an impeller.

A typical turbo blower as a rotating device of this type includes an impeller chamber, a motor chamber, a casing having a partition wall that partitions these and having a shaft insertion hole, and a motor provided in the motor chamber and driven by a motor. It is known to have a shaft that is rotatably supported by a provided fluid lubricated bearing and has an impeller mounting portion extending on the impeller chamber side, and an impeller attached to the impeller mounting portion. It has been. In such a rotating device, the lubricant supplied to the bearing leaks to the impeller chamber side, and the motor chamber side is prevented in order to prevent the occurrence of a problem in which fluid such as gas passing through the impeller chamber is contaminated. Conventionally, it has been considered to connect exhaust means such as a vacuum pump, flow a part of fluid such as gas passing through the impeller chamber from the impeller chamber to the motor chamber, and push the lubricating liquid back to the motor chamber. (For example, refer to Patent Document 1.) In Patent Document 1, the impeller chamber is described as a circulating gas compression chamber, the motor chamber is described as a bearing holding chamber, and the impeller is described as a turbo blade.
Japanese Patent Laid-Open No. 11-311197

  By the way, if it comprises as the said patent document 1, since the gas which passes this impeller chamber will be wasted by flowing to a motor holding chamber, the quantity of fluids, such as gas which passes this impeller chamber, is maintained. Therefore, it is necessary to replenish fluid to the impeller chamber side from the outside. Therefore, in order to suppress the replenishment amount of the fluid, a minute gap is formed between the shaft and the casing, and the fluid is sealed by a throttling effect by the minute gap. Thus, when a minute gap is formed between the shaft and the casing in this way, conventionally, in order to minimize the outflow to the motor chamber side by reducing the width of the minute gap, a seal portion is provided by precise processing. Yes. However, since processing accuracy is required when forming the seal portion, there is a problem that the manufacturing cost of the seal portion is increased.

  In order to solve such a problem, the present embodiment realizes a configuration in which the lubricant does not remain in the gap between the shaft and the casing.

That is, the rotating device according to the present invention includes a casing having an internal space partitioned into an impeller chamber and a motor chamber by a partition wall and provided with a shaft insertion hole through which the shaft can be inserted, and a motor chamber of the casing. A base that is rotatably supported by a fluid lubrication-type bearing provided, a shaft that has an impeller mounting portion disposed in the impeller chamber, and that is inserted through the shaft insertion hole; and an impeller mounting portion of the shaft An impeller attached to the impeller, a motor provided in the motor chamber for rotationally driving the impeller, and a shaft for rotating the shaft, and exhaust means for keeping the motor chamber at a lower pressure than the impeller chamber. A fluid leakage suppression region for suppressing a flow of fluid from the impeller chamber to the motor chamber using a spiral groove in a gap between the shaft and the shaft insertion hole. Only Rutotomoni, in the region of the motor chamber nearer the fluid leakage suppression area in the gap between the shaft and the shaft insertion hole, with the fluid for urging the fluid into the motor chamber side using a helical groove An urging area is provided, and the urging ability of the fluid urging area is made larger than that of the fluid leakage suppressing area .

  If comprised in this way, the effect which suppresses the wasteful cost of fluids, such as gas, is realized by simple processing which provides a spiral groove in at least one of the shaft or the shaft penetration hole without providing a seal part by precise processing. it can.

  In the rotating device according to the present invention, since the fluid leakage suppression region for suppressing the flow of fluid from the impeller chamber to the motor chamber is provided using the spiral groove, at least one of the shaft or the shaft insertion hole is provided. The effect of suppressing the waste of the gas fluid can be realized at a low cost by a simple process of providing a spiral groove on the surface.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  A turbo blower 100, which is a rotating device according to the present embodiment, is for supplying a fluid such as gas (hereinafter simply referred to as gas) to a laser oscillation unit (not shown) such as a CO2 gas laser, and laser oscillation is performed on a gas circulation path. In series.

  Specifically, as shown in FIG. 1, the turbo blower 100 includes a casing 5 having an internal space partitioned by a partition wall 53 into a turbo blade chamber 51 and a motor chamber 52 by a partition wall 53, and the casing 5. A shaft 2 housed in an internal space, a turbo blade 1 as an impeller attached to the shaft 2, and a motor 4 provided in the motor chamber 52 for rotationally driving the turbo blade 1 to rotationally drive the shaft 2. And a centrifugal type. In the present embodiment, the shaft 2 is used upright.

  The turbo vane chamber 51 of the casing 5 accommodates the turbo vane 1 and the motor chamber 52 accommodates the electric motor 4. The partition wall 53 is provided with a shaft insertion hole 5x through which the shaft 2 can be inserted, and the turbo blade chamber 51 and the motor chamber 52 are communicated with each other through the shaft insertion hole 5x. More specifically, the turbo blade chamber 51 includes a gas introduction port 54 that opens in the top direction of each turbo blade 1 and a gas outlet port 55 that opens to the side of the turbo blade 1. On the other hand, the motor chamber 52 is provided in the vicinity of the center of the motor chamber 52 for disposing the electric motor 4 to be described later, and the motor bearing portion 55 is provided on the upper and lower sides of the motor housing portion 55. The upper and lower bearing arrangement portions 57a and 57b are provided, and the oil sump portion 58 is provided at the lower end portion and retains lubricating oil OIL which is a lubricating liquid for bearing lubrication. In this embodiment, the gas in the motor holding chamber 52 is exhausted by the exhaust means so that the gas flows through the gap between the shaft insertion hole 5x and the shaft 2 in the direction toward the motor chamber 52. The motor chamber 52 is evacuated by a certain vacuum pump 9 so as to be kept at a lower pressure than the turbo blade chamber 51.

  The upper and lower rolling bearings 3 and 3 are respectively supported by upper and lower bearing arrangement portions 57a and 57b in the motor chamber 52, and are respectively disposed above and below the electric motor 4 described later. In this embodiment, angular type bearings are used as the rolling bearings 3 and 3 so that both loads acting in the journal direction and the thrust direction can be supported. These rolling bearings 3 and 3 are fluid lubrication type bearings that receive supply of a lubricant, specifically, lubricating oil OIL, through an oil supply path 21a provided in the shaft 2 to be described later.

  The shaft 2 is rotatably supported by the rolling bearing 3 disposed in the motor chamber 52, and has a base portion 21 having an oil supply passage 21a therein, and is extended from the base portion 21 and the shaft. An intermediate portion 22 that passes through the insertion hole 5x, and a turbo blade attachment portion 23 that extends from the intermediate portion 22 and is disposed in the turbo blade chamber 51 as a impeller attachment portion. The oil supply passage 21 a formed inside the base portion 21 opens at the lower end surface of the shaft 2, and the opening is immersed in the lubricating oil OIL in the oil sump portion 58. Moreover, it is comprised so that it may each open also to the outer peripheral surface of the shaft 2 in the upper side of each rolling bearing 3. FIG. The lower end portion 21b of the oil supply path 21a is configured to function as a centrifugal pump portion. Specifically, it has a tapered shape whose cross-sectional area decreases downward. That is, the lubricating oil OIL is raised from the oil sump 58 along the taper surface by the centrifugal force generated by the rotation of the shaft 2, and the sucked oil is sprayed from the openings provided on the outer peripheral surface of the shaft 2 and supplied to each rolling bearing 3. It is configured to be able to. The lubricating oil OIL also exists in a sprayed state in the motor chamber 52 due to the rotation of the shaft 2.

  The turbo blade 1 is generally known in which a plurality of blade bodies 12 are installed in a spiral shape on a slope portion of a truncated conical base 11, and is attached to a turbo blade attachment portion 23 of the shaft 2.

  The electric motor 4 is, for example, a DC brushless type in which a rotor 41 is externally fitted and fixed to the shaft 2, and a stator 42 is disposed around the rotor 41 and supported by a casing 5. The shaft 2 is directly driven to rotate. In this embodiment, an inverter (not shown) is used as a drive source for the shaft 2 and the electric motor 4.

  Accordingly, in this embodiment, as shown in FIG. 1 and FIG. 2 which is an enlarged view of the vicinity of the shaft insertion hole 5x in FIG. 1, the present embodiment is arranged between the shaft 2 and the shaft insertion hole 5x. In the gap S, a fluid leakage suppression region A2 for suppressing the flow of fluid from the turbo blade chamber 51 to the motor chamber 52 using the second spiral groove 2y is provided. Specifically, the apparent position of the intermediate portion 22 of the shaft 2 near the turbo blade chamber 51 is moved toward the turbo blade chamber 51 according to the rotation of the shaft 2 in the direction of the arrow x in FIG. Such a second spiral groove 2y is provided. Here, FIG. 3 shows a state in which the phase is shifted by 90 degrees from the state shown in FIG. Hereinafter, the spiral groove in which the apparent position of the thread located between the spiral grooves moves to the motor chamber 52 side in accordance with the rotation of the shaft 2 in the arrow x direction is referred to as a forward screw groove. Further, the spiral groove in which the apparent position of the thread located between the spiral grooves moves to the turbo blade chamber 51 side in accordance with the rotation of the shaft 2 in the arrow x direction is referred to as a reverse screw groove.

  When the shaft 2 is rotated in the direction of the arrow x in FIG. 2, the fluid in the second spiral groove 2 y, specifically, the gas that has entered the second spiral groove 2 y mainly from the turbo blade chamber 51. Is biased to move in the direction opposite to the arrow x direction in the second spiral groove 2y. That is, since the second spiral groove 2y is a reverse screw groove as described above, the fluid is urged toward the turbo blade chamber 51, that is, opposite to the gas flow direction. In addition, the minute gap SSS located between the thread 2y1 forming the second spiral groove 2y and the shaft insertion hole 5x also moves as the shaft 2 rotates. The lubricating oil OIL entering the minute gap SSS is also urged by the thread 2x1 and moves in the direction of the arrow x at a speed lower than the rotational speed of the shaft 2, and enters the second spiral groove 2y. Reach.

  Moreover, in this embodiment, as shown in the said FIG.1 and FIG.2, in the area | region near the said motor chamber 52 rather than the said fluid leakage suppression area | region A2 in the clearance gap S between the said shaft 2 and the said shaft insertion hole 5x. The fluid energizing region A1 for energizing the fluid toward the motor chamber 52 using the first spiral groove 2x is provided. Specifically, a first spiral groove 2x that is a forward screw groove is provided in a portion of the intermediate portion 22 of the shaft 2 near the motor chamber 52.

  When the shaft 2 is rotated in the direction of the arrow x in FIG. 2, the fluid in the first spiral groove 2x, specifically, the mixture of gas and fine particles of the lubricating oil OIL, etc., is the first spiral groove. It is urged to move in the direction opposite to the arrow x direction within 2x. That is, since the first spiral groove 2x is a forward screw groove as described above, the fluid is biased toward the motor chamber 52, and fine particles of the lubricating oil OIL are discharged to the motor chamber 52. Further, the minute gap SS located between the screw thread 2x1 forming the first spiral groove 2x and the shaft insertion hole 5x moves as the shaft 2 rotates. The lubricating oil OIL entering the minute gap SS is also urged by the thread 2x1 and moves in the direction of the arrow x at a speed lower than the rotational speed of the shaft 2, and enters the first spiral groove 2x. After reaching, the first spiral groove 2x is urged to move toward the motor chamber 52 side as described above.

  In the present embodiment, in order to ensure the flow of fluid from the turbo blade chamber 51 to the motor chamber 52, the portion corresponding to the portion between the fluid energizing region A1 and the fluid leakage suppressing region A2 of the shaft 2 A small-diameter portion 221 having a diameter smaller than a portion corresponding to at least the thread 2x1, 2y1 of the fluid energizing region A1 and the fluid leakage suppression region A2 is provided, and between the small-diameter portion 221 of the shaft 2 and the shaft insertion hole 5x. The width of the gap S in the part is made larger than the width of the gap S in the fluid urging region A1 and the fluid leakage suppression region A2.

  Further, even when the pressure difference between the motor chamber 52 and the turbo blade chamber 51 is reversed due to pressure pulsation on the motor chamber 52 side, the above-described fluid flow from the turbo blade chamber 51 to the motor chamber 52 is ensured. In order to be able to do so, the urging capability by the fluid urging region A1 is made larger than the suppressing capability of the fluid leakage suppression region A2.

  As described above, according to the configuration of the turbo blower 100 that is the turbo rotating device according to the present embodiment, the second spiral groove that is a reverse screw groove closer to the turbo blade chamber 51 than the fluid biasing region A1. Since the fluid leakage suppression region A2 for urging the fluid to the turbo blade chamber 51 side using 2y is provided, gas flows in the second spiral groove 2y in the turbo blade chamber 51 in this fluid leakage suppression region A2. It is energized in the direction of moving to the side, and the outflow of gas from the turbo blade chamber 51 to the motor chamber 52 can be suppressed. Further, since the minute gap SSS located between the screw thread 2y1 forming the second spiral groove 2y and the shaft insertion hole 5x moves as the shaft 2 rotates, the above-described action causes the lubricating oil OIL to have surface tension. Therefore, it is possible to prevent staying in the minute gap SSS.

  Further, in the present embodiment, the fluid is urged toward the motor chamber 52 using the first spiral groove 2x that is a forward screw groove in the gap S between the shaft 2 and the shaft insertion hole 5x. Since the fluid energizing region A1 is provided, the fine particles of impurities such as the lubricating oil OIL that have reached the fluid energizing region A1 together with other fluids such as the surrounding gas as the shaft 2 rotates are rotated in the first spiral groove. It is urged to move in the 2x toward the motor chamber 52 and is discharged into the motor chamber 52. Therefore, even when the pressure difference between the motor chamber 52 and the turbo blade chamber 51 immediately after startup of the vacuum pump 9 is small, impurities such as the lubricating oil OIL can be discharged into the motor chamber 52, and the impurities are turbocharged. It is possible to prevent the gas that enters the blade chamber 51 side and passes through the turbo blade chamber 51 from being contaminated. Further, since the minute gap SS located between the screw thread 2x1 forming the first spiral groove 2x and the shaft insertion hole 5x moves with the rotation of the shaft 2, the lubricating oil OIL is subjected to surface tension by the above-described action. Therefore, it is possible to prevent the oil from staying in the minute gap SS. Therefore, it is possible to prevent deterioration of the lubricating oil OIL due to frictional heat generated between the shaft 2 and the shaft insertion hole 5x or mixing with minute particles. .

  The present invention is not limited to the embodiment described above.

  For example, instead of the fluid leakage suppression region A2 using the second spiral groove 2y as described above, a forward screw groove 5z formed on the shaft insertion hole 5x side is used as shown in FIG. The fluid leakage suppression area AA2 may be formed. When such a fluid leakage suppression area AA2 is provided, when the shaft 2 is rotated in the direction of the arrow x in FIG. 4, the fluid in the forward screw groove 5z is also urged to advance in the direction of the arrow x accordingly. That is, the fluid in the forward screw groove 5z is biased toward the turbo blade chamber 51 side.

  Further, instead of the fluid energizing region A1 using the first spiral groove 2x as described above, as shown in FIG. 4 corresponding to FIG. 2 in the above-described embodiment, the shaft insertion hole 5x side is shown. Alternatively, the fluid energizing area AA1 may be provided by using the reverse screw groove 5y engraved in FIG. When such a fluid urging area AA1 is provided, when the shaft 2 is rotated in the direction of the arrow x in FIG. 4, the fluid in the reverse screw groove 5y is also urged to advance in the direction of the arrow x along with this, The fluid in the reverse screw groove 5y moves in the reverse screw groove 5y toward the motor chamber 52 side.

  Of course, at least one of the first and second spiral grooves 2x and 2y, the reverse thread groove engraved on the shaft insertion hole 5x side, and the forward thread groove engraved on the shaft insertion hole 5x side is provided. The fluid urging area A1 according to the embodiment described above and the fluid leakage suppressing area AA2 may be provided at the same time, or the fluid urging area AA1 and the fluid leakage suppressing area A2 according to the embodiment described above. A combination of the above may be adopted.

  Further, the fluid urging regions A1 and AA1 may be omitted, and the fluid leakage suppression regions A2 and AA2 may be provided over substantially the entire extending direction of the shaft of the gap. In this case, as shown in FIG. 5, a large-diameter portion 5x1 having a larger diameter than other portions is formed at the end of the shaft insertion hole 5x on the motor chamber 52 side, and the large-diameter portion 5x1 and the shaft 2 It is preferable that the width of the gap S is increased in the radial direction of the shaft 2 so that the fluid containing the fine particles of the lubricating oil reaching this portion can easily flow toward the vacuum pump 9. Further, if a step portion is provided between the large diameter portion 5x1 and the shaft insertion hole 5x, the motor chamber 52 is transiently in a time zone in which the pressure in the motor chamber 52 becomes higher than that of the turbo blade chamber 51 immediately after activation of the rotating device. However, since the lubricating oil adhering to the wall surface of the large-diameter portion 5x1 can be retained at the stepped portion, the lubricating oil can be prevented from moving toward the turbo blade chamber 51 along the shaft insertion hole 5x. Furthermore, it is more preferable to provide a small diameter portion 221 having a smaller diameter than a portion corresponding to the thread 2y1 at a portion facing the large diameter portion 5x1 of the shaft 2.

  In addition, various modifications can be made without departing from the spirit of the present invention.

1 is a schematic cross-sectional view showing a turbo blower according to an embodiment of the present invention. The enlarged view of the shaft insertion hole vicinity in FIG. The figure which shows operation | movement of the turbo blower which concerns on the same embodiment. The figure corresponding to FIG. 2 in the turbo blower which concerns on the other embodiment of this invention. The figure corresponding to FIG. 2 in the turbo blower which concerns on the other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Turbo blade 2 ... Shaft 2y ... (2nd) spiral groove 3 ... Bearing 4 ... Motor 5 ... Casing 51 ... Turbo blade chamber 52 ... Motor chamber 53 ... Partition 5x ... Shaft insertion hole 9 ... Vacuum pump (exhaust means)
A2 ... Fluid leakage suppression area

Claims (1)

A casing having an internal space partitioned by a partition wall into an impeller chamber and a motor chamber and having a shaft insertion hole through which the shaft can be inserted, and a fluid lubrication type bearing provided in the motor chamber of the casing are rotated. A shaft that has a base portion that is supported and an impeller mounting portion disposed in the impeller chamber and that is inserted through the shaft insertion hole, an impeller that is attached to the impeller attachment portion of the shaft, and the blade A motor provided in the motor chamber for rotationally driving the vehicle, and a motor for rotating the shaft; and an exhaust means for maintaining the motor chamber at a lower pressure than the impeller chamber, shaft in the gap between the insertion hole, provided a fluid leakage suppression area for suppressing the flow to the motor chamber from said impeller chamber of the fluid by using the spiral groove Rutotomoni, the shaft and the sheet A fluid energizing region for energizing the fluid toward the motor chamber using a spiral groove in a region closer to the motor chamber than the fluid leakage suppressing region in the gap between the shaft insertion hole, and A rotating device characterized in that an urging ability by a fluid urging area is larger than an inhibiting ability of the fluid leakage suppressing area .

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