Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
  • F04C29/0042—Driving elements, brakes, couplings, transmissions specially adapted for pumps
  • F04C29/0085—Prime movers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01C—ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES
  • F01C21/00—Component parts, details or accessories not provided for in groups F01C1/00 - F01C20/00
  • F01C21/10—Outer members for co-operation with rotary pistons; Casings
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C23/00—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C23/00—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids
  • F04C23/008—Hermetic pumps
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
  • F04C29/0042—Driving elements, brakes, couplings, transmissions specially adapted for pumps
  • F04C29/005—Means for transmitting movement from the prime mover to driven parts of the pump, e.g. clutches, couplings, transmissions
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
  • F04C29/04—Heating; Cooling; Heat insulation
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C2220/00—Application
  • F04C2220/10—Vacuum
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C2240/00—Components
  • F04C2240/50—Bearings
  • F04C2240/51—Bearings for cantilever assemblies

Definitions

• the present invention relates to pumping units with dry vacuum pumps intended for producing a high vacuum, for use in particular in the semiconductor industry for lowering the pressure in the process chambers from
• the invention relates more particularly to pumping units with vacuum pumps with double rotor, comprising a pump stator with at least one axial internal cavity in which are housed two parallel pump rotors rotatably mounted on corresponding bearings and coupled according to their first end by gears enclosed in an oil pan.
• the first end of one of the rotors is extended by a coaxial motor shaft engaged in the rotor of a motor driving the vacuum pump.
• the motor includes a stator having a stator winding and is enclosed in a crankcase following the oil pan of the gears.
• Known structures of vacuum pumping units are described in EP 0 733 804, US 5,904,473, US 2,940,661, JP 60,259,791.
• FIG 1 In a known vacuum pump, illustrated in Figure 1, the seal is ensured by an intermediate jacket, sealed engaged between the rotor and the stator of the motor.
• FIG 1 there is a longitudinal sectional view showing the first end of the stator 1 of the vacuum pump 100, with a drive shaft 2 extending the pump rotor not shown.
• the motor shaft 2 is engaged in an engine block 200 while being secured to the motor rotor 3.
• the motor rotor 3 is rotatably mounted on bearings inside the motor stator 4 comprising a stator winding 11 supplied by electrical conductors not shown.
• the motor stator 4 - motor rotor 3 assembly is inserted into a motor casing 5.
• Seals can provide sealing around the motor shaft 2 at the inlet of the motor housing 5, to isolate as much as possible the interior atmosphere of the motor housing 5 relative to the upstream compartment 7 containing a set of gears 8 for coupling between two parallel rotors of the vacuum pump 100.
• the set of gears 8 transmits the rotational movement between the two rotors, only one of the rotors being coupled in line with the motor shaft 2.
• the upstream compartment 7 of the gears 8 contains lubricating oil for the gear.
• an additional bearing 15a is placed between the gears 8 and the motor rotor 3.
• the known structure illustrated in FIG. 1 comprises a sealed jacket 9, in the form of a coaxial bell, the base 10 of which is embedded in sealingly along its entire periphery between two parts of the motor housing 5, namely a main part 51 and a fixing base 52.
• the waterproof jacket 9 has a cylindrical intermediate portion 90 which is engaged in the air gap between the motor stator 4 and the motor rotor 3, and which is connected on the one hand to the base 10 of the jacket and to a top 91.
• a first drawback of such a known structure is its complexity, by the fact that it is necessary to assemble and provide several parts, comprising the waterproof jacket 9, and the two-part motor housing 51 and 52. This increases the cost of producing the vacuum pump.
• a second drawback is that the presence of the cylindrical intermediate portion 90 of a sealed jacket 9 engaged in the air gap between the motor stator 4 and the motor rotor 3 requires keeping an air gap of relatively large thickness, which increases consumption electrical energy required to drive the vacuum pump 100.
• Another disadvantage is that the presence of the waterproof jacket 9 leads to increasing the length of the motor, by moving the motor stator 4 and the motor rotor 3 away from the vacuum pump 100, increasing the carrier. engine shaft scythe; this increases the vibrations of the engine, and the noise generated by the vacuum pump 100 - engine block 200 assembly, and requires the presence of the additional bearing 15a between the gears 8 and the engine rotor 3.
• Another disadvantage is also that the waterproof jacket, made of metal, is subjected to an alternating magnetic field in the air gap of the engine. This results in induction currents in the material forming the waterproof jacket, energy losses and additional heating of the motor. These losses increase with the frequency of the magnetic field, and become prohibitive in a four-pole motor powered at double frequency.
• JP 07 317673 a screw pump for various fluids.
• the drive motor is arranged in an intermediate zone of one of the rotor shafts, between the coupling gears of the shafts and the pump rotors.
• the motor housing is separate from the housing of the coupling gears. The structure is neither intended nor adapted to solve the specific sealing problems of vacuum pumps.
• the object of the present invention is in particular to avoid the drawbacks of known structures of vacuum pumps, by proposing a new structure of pumping group with vacuum pump with double rotor associated with a motor whose sealing is both simpler. , less expensive, and more effective.
• the invention aims to eliminate the waterproof jacket 9, replacing it with other means to effectively ensure the seal opposing the migration of the oil and gases through the engine to the atmosphere.
• a double-rotor vacuum pump pumping unit comprises a pump stator with at least one axial internal cavity in which are housed two parallel pump rotors rotatably mounted on corresponding bearings and coupled at their first end by a set of gears enclosed in an oil sump, the first end of one of the pump rotors being extended by a coaxial motor shaft engaged in the rotor of an engine block d driving the vacuum pump, the engine block having a stator winding and being enclosed in a motor housing following the oil sump;
• stator winding of the engine block is embedded in a waterproof resin ensuring a seal preventing the exit of oil and gas to the outside along the supply conductors.
• the one-piece common casing has an intermediate wall between a first compartment containing the motor and a second compartment containing the set of gears, with a passage for the motor shaft and with a dynamic seal to ensure the sealing around the motor shaft between the first compartment and the second compartment.
• the one-piece common casing may advantageously include an axial end opening closed in leaktight manner by a shutter hatch.
• a further reduction in vibrations is obtained by providing that the one-piece common casing is connected to the first end of the pump stator by means of a bearing support comprising a first bearing for guiding the motor shaft disposed closest to the engine. This reduces the overhang of one motor shaft.
• the reduction in length and overhang is further favored by the fact that the impregnation of the motor stator in the waterproof resin allows it to be brought closer to its casing, because the isolation distances can be reduced thanks to the dielectric quality of the waterproof resin.
• FIG. 1 is a longitudinal sectional view of an engine block according to a known structure
• - Figure 2 is a longitudinal sectional view of an engine block structure according to an embodiment of the present invention
• - Figure 3 is a schematic view in longitudinal section showing a vacuum pumping group according to another embodiment of the present invention.
• FIGS. 2 to 4 is a perspective view of the motor housing and the gear housing according to an embodiment of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS
• a vacuum pumping group according to the invention as illustrated in FIGS. 2 to 4 comprises a vacuum pump 100 with double rotor driven by a motor unit 200 supplied with electrical energy by a line supply 12.
• the vacuum pump 100 comprises a pump stator 1 having at least one axial internal cavity 13 in which are housed two parallel pump rotors rotatably mounted on corresponding bearings.
• a pump stator 1 having at least one axial internal cavity 13 in which are housed two parallel pump rotors rotatably mounted on corresponding bearings.
• only one of the pump rotors 14 is shown, held in the pump stator 1 at its first end by a first bearing 15 and held at its second end by a second bearing 16.
• the two pump rotors such as the pump rotor 14 are coupled at their first end by a set of gears 17 enclosed in an oil sump 18.
• the first end of the pump rotor 14 is extended by the coaxial motor shaft 2 penetrating into the motor casing 5.
• the motor shaft 2 is engaged in the motor rotor 3, itself mounted in rotation in the motor stator 4 contained in the motor housing 5.
• the motor stator 4 comprises a stator winding 11 (FIG. 2).
• the motor casing 5 and the oil pan 18 form a one-piece common casing, advantageously made of metal and secured to the first end of the pump stator 1.
• a waterproof resin 19 (FIG. 2), which seals against oils and gases, preventing the outflow of oil and gas out along the conductors of line d '12 motor supply.
• the one-piece common casing 5, 18 has an axial end opening 20, closed in leaktight manner by a shutter hatch 21 with the interposition of an annular seal 22.
• the one-piece common casing comprises, between the engine casing part 5 and the oil pan part 18, an intermediate wall 23, separating the first compartment 24 containing the engine 3, 4 and the second compartment 25 containing the set of gears 17, with an axial passage for the motor shaft and with a dynamic seal 6 to ensure as much as possible a seal around the motor shaft 2 between the first compartment 24 and the second compartment 25.
• the one-piece common casing 5, 18 is connected to the first end of the pump stator 1 by means of a bearing support 26 comprising the first bearing 15 for guiding the motor shaft 2.
• the first bearing 15 is placed as close as possible to the motor unit 200, in order to reduce the overhang of the motor shaft 2.
• the motor housing 5 comprises a pipe
• the structure according to the invention simultaneously ensures better cooling of the pump stator part 1 close to the engine block 200, thanks to the continuous metallic structure formed by the one-piece common housing 5, 18, distinct from the waterproof resin which is confined to the interior of said one-piece common housing 5, 18. Also, by shortening the overhang of the motor shaft 2, vibrations are avoided and the noise generated by the vacuum pumping group is reduced. It thus becomes possible to avoid the need for an additional bearing (15a, FIG. 1) between the gears 17 and the motor rotor 3. In other words, as shown in FIG. 3, the motor shaft 2 is then cantilevered from the first guide bearing 15, that is to say along the motor shaft section 2 carrying the motor rotor 3 and the gears 17.
• the length of the motor stator, and the carrier -the resulting false can be further reduced, for an identical motor torque, by using a 3, 4 pole motor powered at double frequency 2F (in practice 200 Hz for example), instead of a motor with two poles supplied at a single frequency F (in practice 100 Hz for example). Thanks to the absence of a waterproof jacket in the air gap, the use of a four-pole motor powered at double frequency 2F is possible without creating excessive losses of performance. This was not possible with known structures with a tight jacket, since the 2F double frequency operation created excessively large losses in efficiency.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)
• Applications Or Details Of Rotary Compressors (AREA)
• Motor Or Generator Frames (AREA)
• Rotary Pumps (AREA)
• Saccharide Compounds (AREA)
• Jet Pumps And Other Pumps (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (2)

Family

ID=8852631

Family Applications (1)

Country Status (7)

Cited By (5)

Families Citing this family (15)

Citations (6)

Family Cites Families (16)

• 2000
  • 2000-07-18 FR FR0009401A patent/FR2812040B1/fr not_active Expired - Fee Related
• 2001
  • 2001-07-17 JP JP2002512545A patent/JP2004504537A/ja active Pending
  • 2001-07-17 US US10/088,168 patent/US6644942B2/en not_active Expired - Fee Related
  • 2001-07-17 EP EP01958136A patent/EP1301712B1/fr not_active Expired - Lifetime
  • 2001-07-17 DE DE60137772T patent/DE60137772D1/de not_active Expired - Lifetime
  • 2001-07-17 WO PCT/FR2001/002314 patent/WO2002006675A2/fr not_active Ceased
  • 2001-07-17 AT AT01958136T patent/ATE423906T1/de not_active IP Right Cessation

Patent Citations (6)

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