JP2015008591A - Canned motor and vacuum pump device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-conductive and thin-walled can with excellent mechanical strength.SOLUTION: A canned motor 200 comprises: a motor rotor 220 provided in a pump main shaft 310 for rotationally driving a pump rotor; a motor stator 230 arranged outside the motor rotor 220; and a can 240 arranged between the motor rotor 220 and the motor stator 230 and isolating the motor rotor 220 and the motor stator 230. The can 240 is arranged between the motor rotor 220 and the motor stator 230, and includes a cylindrical trunk 242 formed of a resin and a carbon fiber 248 wound around an outer periphery of the trunk 242.

Description

  The present invention relates to a canned motor and a vacuum pump device.

  Conventionally, a vacuum pump device having a motor as described in the following patent document is known. The vacuum pump device is widely used for exhausting process gas in a vacuum chamber in a semiconductor manufacturing process.

  The motor for the vacuum pump device has been made into a canned motor. In the canned motor, a can (partition) is provided between the motor stator and the motor rotor to isolate the motor stator communicating with the atmosphere side and the motor rotor communicating with the pump exhaust part. By using a canned motor, the seal mechanism of the pump shaft can be eliminated, so that the airtight performance can be improved, maintenance-free, and the structure can be simplified.

  The can in the canned motor is desirably as thin as possible in order to reduce the separation distance between the motor stator and the motor rotor. On the other hand, since the can bears a part of the pressure vessel in the vacuum pump device, it is necessary to ensure sufficient strength at least against the external pressure due to the atmosphere. In addition, the can is required to have characteristics such that the gas exhausted by the vacuum pump device is not damaged by corrosion or the like, does not contaminate the vacuum environment, and has heat resistance against heat generation of the motor.

  For this reason, conventional cans are generally formed of a nonmagnetic metal material having corrosion resistance, such as stainless steel or Hastelloy.

Japanese Patent Laid-Open No. 11-89158 JP 2011-101594 A JP 2005-184958 A

  However, when a non-magnetic metal can is used, an eddy current is generated on the surface of the can due to the action of magnetic flux from the motor stator, and the motor efficiency may decrease due to loss at this time.

  Therefore, a technique using a resin can is known in order to prevent a reduction in motor efficiency. Resin cans are usually manufactured by injection molding, but they tend to be thicker than nonmagnetic metal cans to ensure sufficient mechanical strength to withstand pressure fluctuations in the vacuum pump device. become. When the thickness of the can increases, the separation distance between the motor stator and the motor rotor increases, and the motor characteristics may deteriorate.

Accordingly, an object of the present invention is to provide a can that is non-conductive, thin, and excellent in mechanical strength.

One aspect of the canned motor of the present invention is a canned motor used as a rotational drive source of a pump, which is provided on a rotating shaft for rotationally driving the rotor of the pump. A motor rotor, a motor stator disposed outside the motor rotor, a can disposed between the motor rotor and the motor stator, and separating the motor rotor and the motor stator, wherein the can includes a resin, It is formed including carbon fiber.

  In addition, the can may include a cylindrical body portion that is disposed between the motor rotor and the motor stator and is formed of resin, and a carbon fiber that is wound around an outer periphery of the body portion. .

  The can can be formed of a resin containing carbon fibers therein.

  Moreover, one form of the vacuum pump apparatus of this invention was provided with one of said canned motors.

  According to the present invention, a can that is non-conductive, thin, and excellent in mechanical strength can be provided.

FIG. 1 is a cross-sectional view showing a schematic configuration of the vacuum pump device of the present embodiment. FIG. 2 is another cross-sectional view showing a schematic configuration of the vacuum pump device of the present embodiment. FIG. 3 is a cross-sectional view showing a schematic configuration of the canned motor of the present embodiment. FIG. 4 is a diagram showing a schematic configuration of a can used for the canned motor of the present embodiment. FIG. 5 is a cross-sectional view showing a schematic configuration of a canned motor of a comparative example.

  Hereinafter, a canned motor and a vacuum pump device according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a schematic configuration of the vacuum pump device of the present embodiment. FIG. 2 is another cross-sectional view showing a schematic configuration of the vacuum pump device of the present embodiment.

  FIG. 1 shows a cross section including the rotation center axis AR1 of one pump rotor 300 of the pair of pump rotors 300, 400 included in the vacuum pump device 100, and FIG. A cross section including the rotation center axes AR1 and AR2 of both pump rotors 300 and 400 is shown.

  As shown in FIGS. 1 and 2, the vacuum pump apparatus 100 includes a canned motor 200 and a pair of pump rotors 300 and 400 that are rotationally driven by the canned motor 200 (in FIG. 1, one pump rotor 300 is shown). Only shown).

  The pump rotor 300 includes a pump main shaft (rotating shaft) 310, and a first stage pump rotor 312, a second stage pump rotor 314, and a third stage pump rotor 316, which are attached to the pump main shaft 310 at intervals. I have. The pump rotor 400 includes a pump main shaft 410, and a first-stage pump rotor 412, a second-stage pump rotor 414, and a third-stage pump rotor 416 that are attached to the pump main shaft 410 at intervals. Yes.

  The first stage pump rotors 312 and 412, the second stage pump rotors 314 and 414, and the third stage pump rotors 316 and 416 are accommodated in a space formed by the upper casing 320 and the lower casing 330. An upper closing plate 322 is attached to the upper portion of the upper casing 320, and a lower closing plate 332 is attached to the lower portion of the lower casing 330.

  The upper closing plate 322 is formed with an intake port 324 for sucking processing gas into the pump rotors 300 and 400. The lower closing plate 332 is formed with an exhaust port 334 for exhausting the processing gas from the pump rotors 300 and 400.

  An intake side intermediate member 345 that houses pump main shafts 310 and 410 protruding toward the anti-candle motor 200 side is provided on the anti-candle motor 200 side of the upper casing 320 and the lower casing 330. End portions of the pump main shafts 310 and 410 protruding from the intake side intermediate member 345 to the anti-canned motor 200 side are supported by bearings 340 and 440. Further, side caps 350 and 450 are provided on the intake side intermediate member 345 on the side opposite to the canned motor 200. End portions of the pump main shafts 310 and 410 and bearings 340 and 440 are accommodated in side caps 350 and 450.

  An exhaust-side intermediate member 360 is provided on the canned motor 200 side of the upper casing 320 and the lower casing 330, and an exhaust-side cover 370 is provided on the canned motor 200 side of the exhaust-side intermediate member 360. The exhaust side intermediate member 360 and the exhaust side cover 370 accommodate the pump main shafts 310 and 410 protruding from the upper casing 320 and the lower casing 330 to the canned motor 200 side. The pump main shafts 310 and 410 are pivotally supported by bearings 342 and 442 in portions protruding from the space formed by the upper casing 320 and the lower casing 330 to the canned motor 200 side. The bearings 342 and 442 are accommodated in the exhaust side intermediate member 360 and the exhaust side cover 370.

  The exhaust side intermediate member 360 is formed with a groove along the circumferential direction on a surface facing the pump main shafts 310 and 410, and includes the groove between the exhaust side intermediate member 360 and the pump main shafts 310 and 410. Intermediate chambers 362 and 462 are provided. The intermediate chambers 362 and 462 and the exhaust port 334 are communicated with each other through a communication path 364.

  A pair of timing gears 380 and 480 are accommodated in the exhaust side cover 370. The timing gears 380 and 480 are connected to the pump main shafts 310 and 410 and mesh with each other.

  When the canned motor 200 is driven, the timing gear 380 and the pump rotor 300 are rotationally driven. As the timing gears 380 and 480 mesh with each other, the pump rotor 400 is also rotationally driven. The pair of pump rotors 300 and 400 are provided between the inner surfaces of the upper casing 320 and the lower casing 330, and the first stage pump rotors 312 and 412, the second stage pump rotors 314 and 414, and the third stage pump rotors 316 and 416. A slight gap is kept between them, and they rotate synchronously in the opposite direction without contact. As the pair of pump rotors 300 and 400 rotate, the processing gas introduced from the intake port 324 is caused by the first stage pump rotors 312 and 412, the second stage pump rotors 314 and 414, and the third stage pump rotors 316 and 416. It is compressed and transferred and discharged from the exhaust port 334.

  Next, the configuration of the canned motor 200 will be described. FIG. 3 is a cross-sectional view showing a schematic configuration of the canned motor of the present embodiment. FIG. 4 is a diagram showing a schematic configuration of a can used for the canned motor of the present embodiment.

  The canned motor 200 is used as a rotational drive source of the vacuum pump device 100 (pump rotor 300). The canned motor 200 includes a motor rotor 220 provided on a pump main shaft 310 for rotationally driving the pump rotor 300, and a motor stator 230 disposed outside the motor rotor 220. The canned motor 200 includes a can 240 disposed between the motor rotor 220 and the motor stator 230, and a stator frame 250.

  The stator frame 250 includes a frame body 252 and side plates 254. The frame body 252 has a cylindrical shape in which an internal space is formed along the rotation center axis AR1. The side plate 254 has a disc shape and closes the opening of the frame body 252 on the side opposite to the pump rotor 300. The motor rotor 220, the motor stator 230, and the can 240 are accommodated in the internal space of the stator frame 250.

  The motor stator 230 has a configuration in which a coil 234 is mounted on a stator core 232. The motor stator 230 is fixed to the stator frame 250 concentrically with the rotation center axis AR1 by fitting the stator core 232 into the frame body 252.

  The motor rotor 220 is disposed inside the motor stator 230 so as to be concentric with the rotation center axis AR1, and is directly connected to the pump main shaft 310.

  The can 240 is disposed between the motor rotor 220 and the motor stator 230, and is a member for isolating the motor rotor 220 and the motor stator 230 in a state of being in contact with the motor stator 230 (stator core 232). The can 240 includes a body portion 242, a closing portion 244, and a flange portion 246.

  The body portion 242 has a cylindrical shape and is disposed concentrically with the rotation center axis AR1. The body 242 is formed to extend over the entire installation range of the motor stator 230 in the direction of the rotation center axis AR1. The closing part 244 is formed in a disc shape and closes the opening of the end part of the body part 242 on the side opposite to the pump rotor 300. The flange portion 246 is formed to protrude outward from the end portion of the body portion 242 on the pump rotor 300 side. The can 240 is fixed by sandwiching a flange portion 246 between the stator frame 250 and the exhaust side cover 370. The trunk | drum 242, the obstruction | occlusion part 244, and the flange part 246 are formed with resin.

  Here, the can 240 of the present embodiment is formed to include a resin and carbon fiber. Specifically, the can 240 includes carbon fibers 248 that are bonded and wound around the outer periphery of the body 242. More specifically, the carbon fiber 248 is formed in a cylindrical mesh shape (cylindrical net shape). The can 240 is formed by covering a cylindrical mesh-like carbon fiber 248 from the closed portion 244 side, attaching the carbon fiber 248 to the outer peripheral surface of the barrel portion 242, and bonding the carbon fiber 248 to the outer peripheral surface of the barrel portion 242. Note that the end surface 245 of the blocking portion 244 is R-processed so that the cylindrical mesh-like carbon fiber 248 is easily covered. Further, as shown in FIG. 4, the end surface 245 of the closing portion 244 can be tapered. In the present embodiment, an example in which the carbon fiber 248 is wound around and bonded to the outer peripheral portion of the body portion 242 is shown, but the present invention is not limited thereto. For example, the can 240 can be formed by a member containing carbon fiber in the resin.

(Comparative example)
Next, a canned motor of a comparative example will be described. FIG. 5 is a cross-sectional view showing a schematic configuration of a canned motor of a comparative example. The canned motor 500 of the comparative example is different from the can 240 of the present embodiment only in the configuration of the can 540, and the other configurations are the same. So, Can 5
Only 40 will be described, and description of other components will be omitted.

  The can 540 of the comparative example includes a body portion 542, a closing portion 544, and a flange portion 546. The body portion 542 has a cylindrical shape and is disposed concentrically with the rotation center axis AR1. The body portion 542 is formed to extend over the entire installation range of the motor stator 530 in the direction of the rotation center axis AR1. The closing part 544 is formed in a disk shape and closes the opening of the end part of the body part 542 on the side opposite to the pump rotor 300. The flange portion 546 is formed to project outward from the end portion of the body portion 542 on the pump rotor 300 side. The trunk | drum 542, the obstruction | occlusion part 544, and the flange part 546 are formed with resin.

  The can 540 of the comparative example is formed by a body portion 542, a closing portion 544, and a flange portion 546 made of a resin material. Here, since the can 540 serves as a part of the pressure vessel in the vacuum pump device 100, a sufficient strength is required. For this reason, the can 540 (especially the trunk | drum 542) is formed thickly compared with this embodiment.

  On the other hand, according to the present embodiment, it is possible to provide a can that is non-conductive, thin, and excellent in mechanical strength. That is, the can 240 according to the present embodiment is not simply formed of a resin, but is formed of a resin containing carbon fibers, so that the strength can be increased even if the thickness is reduced. For this reason, the can 240 of the present embodiment can be thinner than the can 540 of the comparative example.

  In addition, since the can 240 of the present embodiment has the carbon fiber 248 wrapped around and bonded to the outer peripheral portion of the body portion 242 made of resin, the portion in contact with the processing gas is the resin on the inner peripheral surface of the body portion 242. It turns out that. For this reason, it is possible to suppress the can 240 from being damaged by the processing gas or contaminating the vacuum environment. Further, since the strength of the can 240 can be maintained even in a high temperature environment, the can motor 200 can be heated to a higher temperature than in the past. As a result, the motor for vacuum pump device 100 can be further improved in design freedom and reduced in size and output.

  Moreover, according to this embodiment, the thin can 240 can be comprised with nonelectroconductive materials, such as resin. For this reason, in any canned motor, for example, an AC induction motor or a DC brushless motor, the gap between the motor stator 230 and the motor rotor 220 can be reduced without causing eddy current loss. As a result, it is possible to achieve both high efficiency and cost reduction of the canned motor 200.

DESCRIPTION OF SYMBOLS 100 Vacuum pump apparatus 200 Canned motor 220 Motor rotor 230 Motor stator 240 Can 242 Body part 244 Closure part 245 End surface 246 Flange part 248 Carbon fiber 300,400 Pump rotor 310 Pump spindle 310,410 Pump spindle 410 Pump spindle

Claims (4)

A canned motor used as a rotational drive source of a pump,
A motor rotor provided on a rotary shaft for rotationally driving the rotor of the pump;
A motor stator disposed outside the motor rotor;
A can that is disposed between the motor rotor and the motor stator and separates the motor rotor and the motor stator;
With
The can is formed including resin and carbon fiber.
A canned motor. The canned motor of claim 1,
The can is disposed between the motor rotor and the motor stator, and a cylindrical body formed of resin,
Carbon fibers wound around the outer periphery of the trunk,
A canned motor comprising: The canned motor of claim 1,
The can is formed of a resin in which carbon fibers are contained.
A canned motor.   A vacuum pump device comprising the canned motor according to claim 1.

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