US3777191A - Dynamo electric machine construction - Google Patents

Dynamo electric machine construction Download PDF

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Publication number
US3777191A
US3777191A US00211538A US3777191DA US3777191A US 3777191 A US3777191 A US 3777191A US 00211538 A US00211538 A US 00211538A US 3777191D A US3777191D A US 3777191DA US 3777191 A US3777191 A US 3777191A
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United States
Prior art keywords
rotor
disk
sheet metal
shaft
machine according
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Expired - Lifetime
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US00211538A
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English (en)
Inventor
G Papst
G Wrobel
G Schneider
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ebm Papst St Georgen GmbH and Co KG
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Papst Motoren GmbH and Co KG
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/28—Means for mounting or fastening rotating magnetic parts on to, or to, the rotor structures

Definitions

  • the present invention relates to a dynamo electric machine and more particularly to a fractional horse power small appliance-type dynamo electric machine; and specifically to the rotor construction for a motor.
  • Dynamo electric machines of the fractional horse power type when used as motors, are widely incorporated in axial ventilators, tape recorders, phonographs and turntables, office machinery and the like.
  • the rotor In one construction which is widely used, the rotor is located outside of the stator and it has previously been proposed to make the short circuit cage of the rotor simultaneously in the form of a rotating cover 'or shell, the cover or shell-rotor combination being assembled with a shaft.
  • the shaft itself is customarily of different material, typically steel, and must be interconnected with the rotor housing which is frequently of different material, that is, material which is easy to machine and has a low electrical resistivity. The interconnection be tween the shaft of steel and the housing or casting of a different metal is frequently made by casting a shaft bushing into the rotor itself.
  • Circumferential rotor-type rotors are usually cupshaped, the shaft of the rotor being secured to the bottom of the cup-shaped rotor element.
  • the walls of the rotor element form the electromagnetically active portion of the'motor.
  • the bottom of the cup-shaped element usually is cast from the same material as the squirrel cage and integral with it, and is therefore, for constructional and electrical reasons, usually made of aluminum.
  • the aluminum used is frequently highly puritied aluminum.
  • Such highly purified aluminum has poor strength characteristics and therefore the bottom of the rotor cup must be made relatively thick, and in many constructions it is necessary to include stiffening ribs or the like, particularly when the bottom is pierced with ventilation openings or ducts.
  • motors are directed to decrease their axial length. This is true not only for motors in which the rotor surrounds the stator, but also for motors in which the stator is located outside of the rotor.
  • a central support tube is provided on which bearings are mounted.
  • the rotor is hollow on its inside and secured to a shaft which is inserted about, or within the bearings of the central support tube, to turn therein, or thereover. The rotor thus rotates about the fixed shaft tube and co-acts at its outer surface with the electromagnetic active air gap derived from the stator.
  • the rotating parts of the motor of this type of construction are mechanically similar to the parts of the motor in which the stator is located inside of the motor, so that the same difficulties regarding mechanical attachment of the end shell of the rotor will arise.
  • the axial length of such an interior-type rotor of a dynamo electric machine is less, but it is more expensive than the known construction of internal rotors in which a stack of laminations are secured to the shaft of the machine itself, and in which the shaft is held in bearings fixed to the end bells of the rotor.
  • the dynamo electric machine has a stator and a rotor which is rotatable with a shaft with respect to the stator about the axis of the shaft.
  • the rotor is secured to the shaft at least at one end portion thereof, the attachment arrangement including a disk-shaped metal element, typically steel, of essentially circular outline which has its outer marginal portions cast into cast portions of the rotor.
  • the disk-shaped element is preferably dished, or bowed, and the outer marginal portions may be formed with cut-outs to further improve the intimate connection between the cast rotor structure (for example of highly purified aluminum) with the mechanically strong dished end metal element.
  • the end disk-shaped metal element may bear against the magnetic parts of the rotor structure, or be spaced therefrom by a distance which is selected to leave enough rotor cage material so that the resistivity of the end connections of the rotor is hardly increased over that it would have in the absence of the end portions of the disk-shaped elements, so that the torque is only slightly decreased.
  • the end marginal portions are in contact with the magnetic circuit of the rotor, the end cage connections being cast therearound.
  • the shaft can readily be secured to the end disk, preferably before casting of the end plate into the remainder of the rotor structure, by locating a shaft in a centered cut-out which is partly non-circular, and upsetting a shaft against the originally non-circular opening so that material will flow therebetween, thus forming a reliable tight and secure connection which will not permit relative rotation of the shaft and the rotor structure when finally assembled.
  • FIG. 1 is a vertical cross-sectional view through a motor structure having an outer rotating rotor, integrally connected with the blades of an axial ventilator; the lower half of FIG. 1 is in a section which is rotated by an angle of with respect to the section of the upper half;
  • FIG. 2 is a plan view of an end blank of the rotor end unit
  • FIG. 3 is a transverse cross-sectional view of the end blank of FIG. 2, after the marginal portions are bent;
  • FIG. 4 is a detail view, to an enlarged scale, illustrating one step in the operation of securing a bushing to the end disk;
  • FIG. 5 is a tranverse cross-sectional fragmentary view of the shaft bushing after the next step of the attachment operation, part of which is illustrated in FIG. 4;
  • FIG. 6 is a plan view of another embodiment of an end disk
  • FIG. 7 is a transverse sectional view of the disk of FIG. 6 after bending
  • FIG. 8 is a longitudinal sectional fragmentary view of an external rotor utilizing the end disk of FIG. 7 and cast into the rotor;
  • FIG. 9a is a top view
  • FIG. 9b a bottom view of the rotor of FIG. 8, seen along lines IXa--IXa and IXb-IXb, respectively, of FIG. 8;
  • FIG. I is a longitudinal cross-sectional view of a rotor to rotate within a stator
  • FIG. 11 is a schematic cross-sectional view of an inside-rotating dynamo electric machine, illustrating interconnection of shaft and rotor;
  • FIG. 12 is a cross section along line A-A of FIG. 13a;
  • FIG. 13a is a plan view of half of an end disk illustrating additional air supply to the rotor
  • FIG. 13b is a plan view similar to FIG. 13a illustrating a different embodiment.
  • FIG. 14 is a transverse fragmentary cross-sectional view along lines B-B of FIG. 13b.
  • the external rotor motor 11 of the fan or ventilator of FIG. 1 has an outer housing 12 which is essentially a single cast or extruded unit.
  • a flange 14 to which a mounting plate 15 is secured is secured to one face plate of housing 12.
  • Stator 13 of motor 11 is secured to the bearing tube I7.
  • the interior of the bearing tube includes a pair ofjournal bearings 18, 19, of sintered or similar porous material, having a felt element 20 therebetween to supply lubricant to the bearings.
  • a pair of disks 24 are secured in a recess 23 of plate 15, to form a first thrust bearing for a shaft 25.
  • Shaft 25 has a groove formed at its left end into which a C-ring 26 is snapped, holding four disks 27, forming with the right face of bearing 18 a'second thrust bearing for shaft 25 to secure the shaft 25 in axial position.
  • shaft 25 is held by the two thrust bearings 24 and 18, 27, in a predetermined position, axially, the two bearings 18,19 serving as radial guides for shaft 25.
  • a stator stack of laminations 30 is secured to the carrier tube 17, windings 31 and 31' being inserted into the stator in known manner.
  • Electrical connections 32, 32', carried through an insulating tube 34 are connected to a terminal plate 35 secured to the housing unit 12, and on which a pair of connecting contacts 33, 33' are provided to interconnect with the conductors 32, 32'.
  • Windings 31, 31' have'end loops 36, 37.
  • Shaft 25 has a bushing 41 thereon, preferably formed as a machine part and made of steel.
  • Bushing 41 is nonrotatably secured to shaft 25.
  • a disk-shaped plate 42 is non-rotatably secured to bushing 41.
  • Disk 42 is formed with eight openings 43 (FIG. 2) to permit air to pass therethrough.
  • the outer marginal portions are formed as extending ribs 44 which are cast into the left short circuit ring 45 of the outer rotor housing 46, forming the outer portion of the motor.
  • the outer portion 46 additionally has a rotor lamination stack 47 and a right short circuit ring 48.
  • the short circuit rings 45, 48 are interconnected by rods 49, cast into grooves formed in the lamination stack 47, rods 49 and short circuit rings 45, 48 forming a complete squirrel cage rotor.
  • the material of the electrical conductor portion thereof, that is, the cast material can be aluminum, preferably purified aluminum and, in one form, highly purified aluminum of minimum electrical resistivity.
  • the disk 42 is of strong metal, preferably steel.
  • Fan blades are welded to the external rotor 46, of which two are shown at 52, 53.
  • the end disk 42 is best seen in FIGS. 2 and 3.
  • a flat, circular disk is punched to have the shape shown in FIG. 2.
  • a central opening 54 is formed therein which has noncircular contours, that is, the central opening is formed with three outwardly extending notches 55, offset from each other by and which will be discussed below in greater detail.
  • the marginal portions have cut-outs 57 punched therein so shaped that the remaining ribs 44 at their free ends have T-shaped enlargments 58.
  • the diameter of the marginal portions 44 is so selected that they come close to the outer circumference of the shortcircuit ring 45. During casting, they are so located that the distance between the ends of the lamination stack 47 and that of the ends of portions 44 shown as h" in FIG. 1, is as large as possible consistent with design dimensions. These two criteria, large diameter and largest possible distance of h contribute to reduction of the resistance of the short circuit ring 45 which otherwise would be increased by the presence of the marginal portions 44.
  • the increase in resistance due to marginal portions 44, of much higher resistivity material, typically steel, than the aluminum of short circuit ring 45, should result in only minor decrease of the torque delivered by the motor with respect to a motor which would not have the marginal portions 44 cast therein.
  • Shaft 25 and bushing 41 should be securely interconnected, and have long operating life.
  • Various interconnections can be used.
  • bushing 41 can be welded to the disk 42, particularly by pulse welding, or by brazing, for example by induction brazing.
  • Disk 42 with a bushing 41 of raw blank form as seen in FIG. 4 is inserted into ajig 60.
  • a hold-down tool 61 is placed against the disk 42, to securely hold disk 42 and bushing 41 together.
  • Compressive force is applied in the direction of the arrows in FIG. 4 against a cylindrical punch 62.
  • Punch 62 has a work face 62 which is slightly conical, and punch 62 thus will deform the outer circumference of bushing 41 to result in the final shape shown in FIG. 5, forming'a holding ring 63 and simultaneously flowing the material of bushing 41 into the notches 55 (FIG. 2) in order to provide a stable,
  • FIG. 8 illustrates a rotor 76 for a circumferentialrotor type dynamo electric machine, which could be used instead of rotor 46 in the motor of FIG. I.
  • Rotor 70 includes a lamination stack 71, with a cast short circuit squirrel cage, for example of pure aluminum.
  • An upper short circuit ring 72 and a lower short circuit ring 73 are shown, interconnected by connecting bars which are placed in grooves (not shown) of lamination stack 71.
  • FIG. 5 illustrates a casting apparatus to cast the end plate into the stator assembly. Circumferential edges 79, 79' of a casting apparatus 69, 69 are illustrated in the position ready for casting.
  • the edges 79, 79 are pressed against the end plate 74 with sufficient force that they will form a shallow groove in the end disk 7 for example to the extent of 1/ l0 mm.
  • This slight groove coupled with the pressure of application provides a secure and tight connection against rotor short circuit material, even if introduced by pressure casting.
  • the surfaces of the disk 74 will then have a pair of ring-like depressed zones, of shallow depth, which additionally contribute to stiffening of the end disk.
  • the end disk 74 is secured to the upper short circuit cage 72, by casting its marginal portion into the ring 72 forming the short circuit cage. Again, the distance between the ends of the marginal portion of disk 74 and lamination stack 71 is h, this space being completely filled by cast material of the end ring of the cage, in order to decrease the internal resistance of the end ring as much as possible.
  • FIG. 6 illustrates the punched disk before profile formation, and flat, as it would come from a punch. The disk of FIG. 6 is then shaped to have the form of FIG. 7, with the marginal portions 75-bent over. Holes 76 are punched into the marginal portion to provide for good and intimate interconnection of the end disk with the short circuit ring 72.
  • a bushing 78 is inserted into a central opening 77 for interconnection with a shaft, not shown in FIG. 8. This bushing 77 may again be inserted, by means of circumferential notches (not shown), similar to that described in connection with FIGS. 4 and 5, or welded or brazed, as desired.
  • Pin 82 of the tool centers the disk 74 during casting. The slight deformation of the disk, particularly in combination with previous bowing thereof, effectively stabilizes the shape and orientation of the disk with respect to the rotor after final casting.
  • FIG. 9a is a view of the rotor 76 of FIG. 8 from above.
  • FIG. 9b is a view of the same rotor from below. Holes (FIG. 9a) and holes 87 (FIG. 9b) are provided to permit balancing of the rotor.
  • FIG. It illustrates a rotor 85 which is intended to operate within a stator.
  • Rotor 85 again is a squirrel cage rotor, with an upper short circuit ring 86, a lower short circuit ring 67 and connecting bars (not shown) cast into a rotor lamination stack 86.
  • the upper ring 86 has a disk-shaped member 69 cast therein which, again, is a punched disk.
  • the inner opening 92 of disk 89 has shaft 911 press-fitted therein.
  • the punched disk 89 should be punched with an accurate highly reliable tool, which has a very small cutting gap, so that the cut surface will be true to size over the entire thickness of the punched part, and does not show burrs or broken away zones of excessive tolerance. If disk 89 is accurately punched, shaft M can be press-fitted by means of an interference fit directly, or can be interconnected by means of upsetting, without an additional bushing.
  • FIG. II illustrates, schematically, a rotor construction particularly suitable for a rotor running within a stator, and enabling use of a particularly long bearing tube.
  • Rotor III thus rotates within stator 11111.
  • a stationary bearing tube M2 is located in the interior of rotor III), constructed similarly to bearing tube I7 in accordance with FIG. I.
  • Bearing tube I I2 has a pair of self-lubricating bearings 113 associated therewith, and shaft 1M rotates within the bearings.
  • the upper end of shaft 1114 has a bushing I15 secured thereto.
  • a hatshaped, upset sheet metal disk 1116 is secured to bushing 115.
  • the attachment is at a center, convex portion.
  • the disk-shaped element 74' of FIGS. 12-14 is similar to that of element 74 of FIGS. 8, 9a, 9b.
  • projections and depressions I30 are formed in the disk-shaped element 74, in order to increase the amount of cooling air supplied to the interior of the motor, when the disk rotates during operation of the motor.
  • the projections and depressions I31, 132 as seen in FIGS. I2 and 13a, are bent towards both sides of the element 74, and are arranged in two circumferential rings I311, 132 and 131i, I32, oriented reversely with respect to each other so that air will be supplied regardless of direction of rotation of the rotor.
  • FIG. 13b where disk 74 has flags 1133, I34 punched out, the flags I33, 1134 being of greater radial width and so arranged that they will supply air to the interior of the rotor regardless of direction of rotation of the motor.
  • Rotors, and particularly short circuit rotors of fractional horse power motors can readily be interconnected with associated shafts by practicing the invention as disclosed.
  • the shafts of these rotors will be securely and reliably connected and will be in alignment with the rotors, even after long periods of operation.
  • the axial length of the motor can be reduced.
  • the casting operation itself is simple and presents less difficulties and does not require any special tools or fixtures.
  • said means comprising a disk-shaped sheet metal element of structurally strong material and of essentially circular outline extending diametrically of the motor, said element being centrally secured to the shaft and having outer marginal portions formed with projecting portions the projecting portions extending in axial direction and being cast into and integrally secured within one of the electrically conductive short circuit rings of the rotor.
  • Machine according to claim ll wherein the axially extending marginal portions form projecting ribs which are speced from the magnetic circuit of the rotor by a distance (h) determined by the current flow in the short circuit rings, said distance (h) being selected to introduce additional resistance into the short circuit rings which is small with respect to the resistance of the rings without the marginal portions to minimize power loss of the machine.
  • Machine according to claim l wherein the sheet metal element is formed with a central opening; a bushing inserted into the central opening, the bushing being brazed to the central opening.
  • the sheet metal element is a precision punched part having a central opening punched therein, the central opening being held to accurate tolerance throughout the thickness of the sheet metal element;
  • the shaft being press-fitted into said central opening.
  • Machine according to claim ll wherein the sheet metal element is formed, along its face, with projecting fins punched from the plane of the sheet metal element to provide openings through the sheet metal element and air scoops for ventilation of the interior of the rotor.
  • punched fins are located on concentric circles of the sheet metal element, selected fins projecting in opposite directions to provide air scoops for the interior of the motor regardless of direction of rotation of the rotor.
  • Machine according to claim ll wherein the sheet metal element is deformed by circumferential shallow rings extending concentrically with the shaft into the planeof the sheet metal element.
  • Fractional horse power motor having a shaft, a stator surrounding the shaft windings surrounding the stator, and an external squirrel cage rotor surrounding the stator and having an electromagnetic portion comprising axial conductor bars and integrally connected short circuit end rings comprising a material of good electrical conductivity but of low mechanical strength, and stacks of magnetic laminations being cast between the short circuit end rings;
  • the sheet metal disk having axially extending projecting marginal portions which are cast into and integrally secured into the adjacent short circuit end ring to secure the electromagnetic portion of the rotor directly to the shaft and form a unitary, integral rotor-shaft assembly which can rotate about the stator.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Manufacture Of Motors, Generators (AREA)
  • Induction Machinery (AREA)
  • Motor Or Generator Frames (AREA)
US00211538A 1971-01-08 1971-12-23 Dynamo electric machine construction Expired - Lifetime US3777191A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19712100663 DE2100663A1 (de) 1971-01-08 1971-01-08 Elektrische Maschine, insbesondere Kleinstmotor

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DE (1) DE2100663A1 (Direct)
FR (1) FR2120805A6 (Direct)
GB (1) GB1376221A (Direct)

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2727375A1 (de) * 1976-06-16 1977-12-22 Giorgio Gutris Rotor fuer elektrische in-aus-motoren
US4074158A (en) * 1976-05-14 1978-02-14 Cole James D Electric motor assembly
US4128364A (en) * 1972-11-23 1978-12-05 Papst-Motoren Kg Radial flow fan with motor cooling and resilient support of rotor shaft
US4129796A (en) * 1974-12-13 1978-12-12 Papst-Motoren Kg Stator winding mounting for an electric motor
US4130770A (en) * 1974-02-26 1978-12-19 Papst-Motoren Kg Axial flow fan having improved axial length structure
US4430590A (en) 1982-02-05 1984-02-07 Msl Industries, Inc. Electric motor with unitary rotor housing
US4554472A (en) * 1982-06-14 1985-11-19 Mitsubishi Denki Kabushiki Kaisha Low inertia induction motor
US4564781A (en) * 1981-08-07 1986-01-14 Arnegger Richard E Electrical bell type motor
US4634908A (en) * 1984-06-19 1987-01-06 Ebm Elektrobau Mulfingen Gmbh & Co. External rotor motor with screwed on motor flange
US5153470A (en) * 1990-05-31 1992-10-06 Nippon Densan Corporation Spindle motor
US5610462A (en) * 1993-06-22 1997-03-11 Nidec Corporation Brushless motor
US6044737A (en) * 1997-04-02 2000-04-04 Industrial Technology Research Institute Stator of and arc shaping method for brushless motor
US20030122437A1 (en) * 2001-12-28 2003-07-03 Sunonwealth Electric Machine Industry Co., Ltd. Rotation shaft support structure of motor
US20040032176A1 (en) * 2002-08-16 2004-02-19 Samsung Electro-Mechanics Co., Ltd. Sealing structure for motor using kinetic pressure bearing
US20040212262A1 (en) * 2003-04-23 2004-10-28 Yung-Yu Chiu Fan motor structure
CN1293690C (zh) * 2000-04-19 2007-01-03 美蓓亚株式会社 其电机轭部由填隙或点焊安装的风扇
US20090223163A1 (en) * 2008-03-10 2009-09-10 Shu Ching Quek Wind Turbine Tower Including An Induction Brazed Joint And A Method Of Fabricating The Wind Turbine Tower

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2555671C2 (de) * 1974-12-13 1986-06-26 Papst-Motoren GmbH & Co KG, 7742 St Georgen Elektromotor
DE3318921A1 (de) * 1983-05-25 1984-11-29 Robert Bosch Gmbh, 7000 Stuttgart Motorverdichter

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2441801A (en) * 1946-05-23 1948-05-18 Otto E Dever Self-driven wheel
US2742223A (en) * 1952-12-13 1956-04-17 Font Eduardo Soler Electric propeller fans and the like
US2926838A (en) * 1958-10-07 1960-03-01 Jacobus Constant Van Rijn Ventilating motor and fan
US2990112A (en) * 1959-05-28 1961-06-27 Gen Motors Corp Ventilating means
US3229897A (en) * 1963-01-14 1966-01-18 Papst Hermann Ventilator
NL7006439A (Direct) * 1969-05-14 1970-11-17
US3596121A (en) * 1969-09-10 1971-07-27 Robbins & Myers Electric induction motor

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2441801A (en) * 1946-05-23 1948-05-18 Otto E Dever Self-driven wheel
US2742223A (en) * 1952-12-13 1956-04-17 Font Eduardo Soler Electric propeller fans and the like
US2926838A (en) * 1958-10-07 1960-03-01 Jacobus Constant Van Rijn Ventilating motor and fan
US2990112A (en) * 1959-05-28 1961-06-27 Gen Motors Corp Ventilating means
US3229897A (en) * 1963-01-14 1966-01-18 Papst Hermann Ventilator
NL7006439A (Direct) * 1969-05-14 1970-11-17
US3596121A (en) * 1969-09-10 1971-07-27 Robbins & Myers Electric induction motor

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4128364A (en) * 1972-11-23 1978-12-05 Papst-Motoren Kg Radial flow fan with motor cooling and resilient support of rotor shaft
US4130770A (en) * 1974-02-26 1978-12-19 Papst-Motoren Kg Axial flow fan having improved axial length structure
US4129796A (en) * 1974-12-13 1978-12-12 Papst-Motoren Kg Stator winding mounting for an electric motor
US4074158A (en) * 1976-05-14 1978-02-14 Cole James D Electric motor assembly
DE2727375A1 (de) * 1976-06-16 1977-12-22 Giorgio Gutris Rotor fuer elektrische in-aus-motoren
US4186479A (en) * 1976-06-16 1980-02-05 Giorgio Gutris Process for manufacturing rotors for in-out electric motors
US4564781A (en) * 1981-08-07 1986-01-14 Arnegger Richard E Electrical bell type motor
US4430590A (en) 1982-02-05 1984-02-07 Msl Industries, Inc. Electric motor with unitary rotor housing
US4554472A (en) * 1982-06-14 1985-11-19 Mitsubishi Denki Kabushiki Kaisha Low inertia induction motor
US4634908A (en) * 1984-06-19 1987-01-06 Ebm Elektrobau Mulfingen Gmbh & Co. External rotor motor with screwed on motor flange
US5153470A (en) * 1990-05-31 1992-10-06 Nippon Densan Corporation Spindle motor
US5610462A (en) * 1993-06-22 1997-03-11 Nidec Corporation Brushless motor
US6044737A (en) * 1997-04-02 2000-04-04 Industrial Technology Research Institute Stator of and arc shaping method for brushless motor
CN1293690C (zh) * 2000-04-19 2007-01-03 美蓓亚株式会社 其电机轭部由填隙或点焊安装的风扇
US20030122437A1 (en) * 2001-12-28 2003-07-03 Sunonwealth Electric Machine Industry Co., Ltd. Rotation shaft support structure of motor
US6617730B2 (en) * 2001-12-28 2003-09-09 Sunonwealth Eletric Machine Industry Co., Ltd. Rotation shaft support structure of motor
US20040032176A1 (en) * 2002-08-16 2004-02-19 Samsung Electro-Mechanics Co., Ltd. Sealing structure for motor using kinetic pressure bearing
US6774516B2 (en) * 2002-08-16 2004-08-10 Samsung Electro-Mechanics Co., Ltd. Sealing structure for motor using kinetic pressure bearing
US20040212262A1 (en) * 2003-04-23 2004-10-28 Yung-Yu Chiu Fan motor structure
US20090223163A1 (en) * 2008-03-10 2009-09-10 Shu Ching Quek Wind Turbine Tower Including An Induction Brazed Joint And A Method Of Fabricating The Wind Turbine Tower

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Publication number Publication date
GB1376221A (en) 1974-12-04
FR2120805A6 (Direct) 1972-08-18
DE2100663A1 (de) 1972-07-20

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