Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D25/00—Pumping installations or systems
  • F04D25/02—Units comprising pumps and their driving means
  • F04D25/06—Units comprising pumps and their driving means the pump being electrically driven
  • F04D25/0606—Units comprising pumps and their driving means the pump being electrically driven the electric motor being specially adapted for integration in the pump
  • F04D25/0613—Units comprising pumps and their driving means the pump being electrically driven the electric motor being specially adapted for integration in the pump the electric motor being of the inside-out type, i.e. the rotor is arranged radially outside a central stator
  • F04D25/062—Details of the bearings
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D29/00—Details, component parts, or accessories
  • F04D29/05—Shafts or bearings, or assemblies thereof, specially adapted for elastic fluid pumps
  • F04D29/051—Axial thrust balancing
  • F04D29/0513—Axial thrust balancing hydrostatic; hydrodynamic thrust bearings
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D29/00—Details, component parts, or accessories
  • F04D29/66—Combating cavitation, whirls, noise, vibration or the like; Balancing
  • F04D29/661—Combating cavitation, whirls, noise, vibration or the like; Balancing especially adapted for elastic fluid pumps
  • F04D29/668—Combating cavitation, whirls, noise, vibration or the like; Balancing especially adapted for elastic fluid pumps damping or preventing mechanical vibrations

Definitions

• the invention relates to an axial fan with an external rotor drive motor, the external rotor of which has a permanent magnet.
• this object is achieved by an axial fan with an external rotor drive motor, the external rotor provided with a rotor shaft which drives a fan wheel and rotates around an internal stator during operation, wherein a bearing support tube is arranged in the internal stator, in which a radial plain bearing is arranged which supports the shaft of the outer rotor, and with an axial sliding bearing which is provided between a free end of the rotor shaft and a stationary counterpart, the latter having a thrust element which is carried by an elastomer molding.
• the transmission of rattling noises to the fan housing is damped and reduced by the elastomer fitting and the specified design.
• Fig. 1 shows a greatly enlarged longitudinal section through an inventive Axial fan
• FIG. 2 is a plan view of the axial fan of FIG. 1, seen in the direction of arrow II of FIG. 1,
• FIG. 3 shows a greatly enlarged detail from FIG. 1 with an elastomer molding shown in FIG. 4, seen along the line III-III of FIG. 4,
• FIGS. 1 to 3 shows a top view of the elastomer molding used in FIGS. 1 to 3, in a very large enlargement
• FIGS. 1 to 4 shows a first variant of the fan of FIGS. 1 to 4,
• FIGS. 1 to 4 shows a second variant of the fan of FIGS. 1 to 4,
• FIGS. 1 to 4 shows a third variant of the fan of FIGS. 1 to 4,
• FIG. 8 shows a section through a fourth variant of the invention, seen along the line VIII-VIII of FIG. 9,
• Fig. 9 is a plan view, seen in the direction of arrow IX of Fig. 8, and
• FIGS. 8 and 9 are spatial representation of the elastomer molding of FIGS. 8 and 9 with the thrust element 156 fastened therein.
• the invention is preferably applied to very small fans, such as those e.g. used in computers to cool the processor, or in vehicles to cool vehicle parts.
• the length 1 cm is therefore given by way of example in FIG. 2 and the length 1 mm in FIGS. 3 and 4. Details could not be displayed on a 1: 1 scale, which is why enlarged representations must be used.
• Fig. 1 shows a longitudinal section through an axial fan 10.
• This has an outer ring 12 which is used for mounting on a device (not shown) or the like.
• a plastic fan housing 16 is in the outer ring 12 by means of a tensioned rubber cord 14, which serves to absorb shock, in the manner shown suspended elastically to reduce the transmission of shocks and vibrations.
• the rubber cord 14 has evenly distributed suspension points 15 on the outer ring 12 and, offset from them, evenly distributed fastening points 17 on the fan housing 16.
• an intermediate space 19 is provided in order to ensure free movement of the fan housing 16 in the outer ring 12 .
• the fan housing 16 has on its periphery an air guide ring 18, to which a shell-shaped motor support part 22 is connected by means of three spokes 20, which is also referred to as a motor flange and on which an electronically commutated motor 23 is arranged.
• the support member 22 has in the middle a hollow cylindrical receptacle 24 for a bearing support tube 26, in which a sintered bearing 28 is fastened by pressing.
• the latter serves as a radial slide bearing for the shaft 30 of an outer rotor 32, the rotor bell 34 (made of plastic) is fastened to the upper end of the shaft 30 in the manner shown.
• the rotor bell 34 has fan blades 36 which convey the air in the direction of the arrows 38, that is to say downwards in FIG. 1. This causes a reaction force on the outer rotor 32 which acts upwards, that is to say opposite to the force K shown in FIGS. 1 and 3.
• a magnetic iron return ring 40 is fastened in the rotor bell 34 by injection molding, and a rotor magnet 42 which is radially magnetized is fastened therein, cf. EP-A, 0766370.
• the lower end of the rotor shaft 30 in FIG. 1 has an annular groove 46 (FIG. 3) in which a locking washer 48 is fastened. This is a short distance, e.g. 0.2 mm, from the lower end 50 of the sintered bearing 28 and thereby prevents major axial displacements of the rotor shaft 30 when strong accelerations act on the fan 10.
• the rotor shaft 30 has at its free end a rounding 54 (FIG. 3), which is also referred to as a track tip, and which - as an axial sliding bearing - bears against a thrust element 56 or 156 (FIGS. 8 to 10), e.g. in the form of a thrust washer made of polyamide, to which molybdenum disulfide is added as a lubricant.
• a rounding 54 FIG. 3
• a thrust element 56 or 156 e.g. in the form of a thrust washer made of polyamide, to which molybdenum disulfide is added as a lubricant.
• a claw pole stator 60 is fastened in the manner shown, which has two claw pole plates 62, 64, between which there is there is a coil 66 which wraps around the rotor shaft 30.
• a circuit board 68 which carries electronic components for the motor (ECM) 23, for example a (not shown) Hall IC.
• the rotor magnet 42 is here offset axially upwards relative to the pole plates 62, 64, and this causes an axial magnetic force K on the rotor 32 in the downward direction because the latter is pulled downwards by the pole plates becomes.
• the force K presses the tip 54 (FIG. 3) against the thrust washer 56.
• the thrust washer 56 is held in a mold cavity 72 (FIG. 3) in the middle of an elastomer molding 70.
• This mold cavity 72 has an elevation 74 in the center, which could also be called a base or pedestal and on which the underside of the Thrust washer 56 rests, cf. Fig. 3. If a shock acts downward on the rotor 32, the base 74 is elastically compressed, as it were the first line of defense, and thereby dampens the shock.
• the thrust washer 56 is held at the top by an annular bead 73.
• part 70 - in plan view - looks like a ship's propeller.
• the peripheral parts of the tab 76 are arranged in the manner shown between the fan housing 16 and the underside of the bearing support raw res 26.
• the fan housing 16 has a recess 80, the size of which is adapted to the shaped piece 70.
• the recess 80 has a central hole 82 at the bottom, and around it three evenly distributed holes 84, cf. Fig. 2. It has been shown that such holes can further improve sound absorption.
• MQ silicone rubber
• MFQ fluorosilicone rubber
• NR natural rubber
• NBR butandene acrylonitrile rubber
• PUR polyurethane
• PUR elastomers The hardness of the polyurethane or other material used is determined by the adapted to the respective application. The optimal hardness can only be determined by tests
• the base 74 is first deformed. An internal damping then takes place in the material of the shaped piece 70, which acts like a buffer, so that the impact is largely absorbed. Due to the internal damping in the fitting 70, the vibrations are reduced or converted into heat. Therefore, they are only passed on to the fan housing 16 in a greatly weakened form. Since this consists essentially of plastic, it also has a damping effect. Overall, rattling of the fan 10 is largely avoided in this way, even in the event of strong shocks and impacts.
• the cavities 80 What is achieved by the cavities 80 is that the material of the shaped piece 70 can laterally deflect under axial load, and therefore the shaped piece 70, despite its small size, acts like a buffer.
• such cavities can take many forms, and FIGS. 4 and 9 are therefore only to be understood as preferred examples.
• a shaped piece 70 ' is injected into the recess 80 and anchored at the bottom of the central recess 82 by an undercut.
• the thrust washer 56 is fastened in a manner similar to that in FIGS. 1 to 4, but there is also a recess 90 beneath it, which can further improve the sound insulation.
• the shaped piece 70 "has a projection or nipple 92, which is pulled downward in the direction of arrow 96 through the central recess 82 during assembly and snaps in there by means of its annular groove 94. This enables very simple, automated assembly .
• FIGS. 8 to 10 show a fourth variant of the invention.
• This uses an elastomer fitting 170, which is largely identical to the fitting 70 of FIG. 4 and can be used in its place in the engine according to FIGS. 1 to 3.
• the difference from FIG. 4 lies in the mold cavity 172, whose outer circumference 171 tapers somewhat from bottom to top in the manner shown, so that it is very easy to mechanically mount a thrust washer 156 (FIG. 10) in this mold cavity 172.
• the mold cavity 172 has an elevation 174 in the middle, on which - as in FIG. 3 - the underside of the thrust washer 156 (FIG. 10) rests.
• the top of the thrust washer 156 is held by the upper edge 173 of the mold cavity 172.
• the shaped piece 170 has a central part 175 which receives the thrust washer 156, and three parts 176 protrude from this part at intervals of 120 °, between which there are cavities 178.
• the advantage of the fourth variant is the simpler attachment of the thrust washer 156.
• the mode of operation is identical to that of the previous exemplary embodiments.
• the outside diameter of the part 170 shown in FIG. 9 can be, for example, 5.5 mm.
• the invention results in a strong reduction in noise, especially in mobile applications.
• the sandwich construction shown is preferably used, but multiple modifications and modifications are possible within the scope of the invention.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)
• Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)
• Motor Or Generator Frames (AREA)
• Motor Or Generator Cooling System (AREA)
• Permanent Magnet Type Synchronous Machine (AREA)
• Manufacture Of Motors, Generators (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=8062073

Family Applications (1)

Country Status (6)

Cited By (1)

Families Citing this family (36)

Family Cites Families (15)

• 1999
  • 1999-08-21 DE DE29914693U patent/DE29914693U1/de not_active Expired - Lifetime
  • 1999-08-25 AT AT99944510T patent/ATE218250T1/de not_active IP Right Cessation
  • 1999-08-25 DE DE59901568T patent/DE59901568D1/de not_active Expired - Lifetime
  • 1999-08-25 US US09/763,719 patent/US6507135B1/en not_active Expired - Lifetime
  • 1999-08-25 EP EP99944510A patent/EP1108280B1/fr not_active Expired - Lifetime
  • 1999-08-25 WO PCT/EP1999/006230 patent/WO2000013294A1/fr active IP Right Grant
  • 1999-08-25 JP JP2000568166A patent/JP4261773B2/ja not_active Expired - Fee Related

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events