WO1998010505A1 - Dc motor with permanent magnet stator - Google Patents

Dc motor with permanent magnet stator Download PDF

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Publication number
WO1998010505A1
WO1998010505A1 PCT/HU1997/000048 HU9700048W WO9810505A1 WO 1998010505 A1 WO1998010505 A1 WO 1998010505A1 HU 9700048 W HU9700048 W HU 9700048W WO 9810505 A1 WO9810505 A1 WO 9810505A1
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WO
WIPO (PCT)
Prior art keywords
poles
segments
layer
axle
rotor
Prior art date
Application number
PCT/HU1997/000048
Other languages
French (fr)
Inventor
Erno^' SZÁRAZ
Original Assignee
Szaraz Erno
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Szaraz Erno filed Critical Szaraz Erno
Priority to AU43923/97A priority Critical patent/AU4392397A/en
Publication of WO1998010505A1 publication Critical patent/WO1998010505A1/en

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K23/00—DC commutator motors or generators having mechanical commutator; Universal AC/DC commutator motors
    • H02K23/02—DC commutator motors or generators having mechanical commutator; Universal AC/DC commutator motors characterised by arrangement for exciting
    • H02K23/04—DC commutator motors or generators having mechanical commutator; Universal AC/DC commutator motors characterised by arrangement for exciting having permanent magnet excitation

Definitions

  • This invention relates to a DC motor with brushes, having a rotor comprising an axle and packets of soft-iron lamellas perpendicular to the axle and constituting poles, coils of conducting wire are provided on the poles, and the wire terminals are attached to a collector, the rotor is within a cylindrical housing with permanent magnets fastened on its inner surface.
  • Hungarian patent HU 193 867 disclosed an electric motor with external rotor assembly excited by permanent magnet, in which the rotor forming the outer housing as well has an inner surface on which permanent magnets are fastened, and these magnets are used at the same time to control the motor. Manufacturing the electric motor according to this patent is sophisticated and requires considerable costs.
  • German patent DE 3 807 377 disclosed an enhanced electric motor which comprises magnets in both its rotor and its stator, used together with electromagnets. The combination of magnets and electromagnets is intended to produce enhanced torque.
  • German patent DE 3 636 376 had as its object to provide a loss- free electric motor. Attaining this aim seemed to be unrealistic. In this embodiment the inventors tried to overcome the troubles with a rotary magnet assembly in which the turning of the permanent magnets to the left and to the right takes place by electromagnets excited through a left run- braking ring and a right run-braking ring.
  • the object of the presented invention is to provide an electric motor of enhanced efficiency which can be manufactured easily by conventional means and constructed of conventional components.
  • the invention is based on an observation that by attaching distinct layers of magnets to each other, for example by adhesive, one can obtain greater torque, which can further be enhanced when the magnets are combined to ferrite-magnets and steel-magnets, and even further enhance when the steel-magnets are shared into further segments.
  • the DC motor according to the invention applied with brushes has a rotor comprising an axle and packets of soft-iron lamellas perpendicular to the axle and constituting poles, coils of conducting wire are provided on the poles, and the wire terminals are attached to a collector.
  • the rotor is within a cylindrical housing with permanent magnets fastened on its inner surface.
  • the permanent magnets are arranged in at least two layers, where a first layer of a single piece and a second layer of several segments extending parallel to the longitudinal direction of the axle are arranged.
  • the length of the segments are equal to that of the first layer taken in the longitudinal direction of the axle, and the width of the segments are of uniform 1/n share of the ring constituted by the segments, where n is identical to the number of poles if that number is even, or is greater by one than the number of poles if that number is odd.
  • the number of the segments is two less than the number of poles in the case of ten or less poles, or four less than the number of poles in the case of more than ten poles.
  • the segments are arranged in two groups in axial symmetry where the width of the first layer is defined by the central angle of the segments attached to each other and to the first layer.
  • the first layer is attached to the inner surface of the housing by adhesive.
  • the first layer is made of ferrite-magnet
  • the seg- ments of the second layer are made of steel-magnet.
  • a third layer of a single piece is provided between the rotor and the segments of the second layer, which has a length equal to those of the two groups, has a width defined by the central angle of the segments, made of ferrite-magnet, and attached to the second layer by adhesive.
  • the poles of the layers in each group are of the same sequence in direction perpendicular to the axle.
  • Figure 1 shows a cross-section of a motor with a rotor of 12 poles and having groups of magnets in two layers
  • Figure 2 shows a cross-section of a motor with a rotor of 8 poles having groups of magnets in two layers
  • Figure 3 shows a cross-section of a motor with a rotor of 12 poles having groups of magnets in three layers
  • Figure 4 shows a cross-section of a motor with a rotor of 11 poles and having groups of magnets in two layers
  • FIG. 5 shows a cross-section of a motor with a rotor of 7 poles and having groups of magnets in two layers.
  • the structure of the motors illustrated in the Figures are very similar.
  • Conventional elements, such as rotor 4 and housing 2 of motors well-known from the art are kept in unchanged form, i.e. rotor 4 is constructed of packets of soft-iron lamellas stowed by their plane surface and these packets are mounted perpendicularly to an axle 1.
  • the soft- iron lamellas of the rotor 4 constitute poles 3, onto which coils of conducting wire are provided.
  • the wire terminals are attached to a collector. Voltage is applied to the collector through carbon brushes.
  • Housing 2 is made of steel with the axle 1 built on bearings in its centre. The difference between the shown motors and the prior art motors lies in the construction and arrangement of the magnets.
  • the permanent magnets have been attached by an adhesive or glue to the inner surface of the housing 2, in the height of the soft-iron lamellas of the rotor 4, at least in two layers.
  • the first layer 5 is made of a single piece while the second layer 6 is constructed of several segments 7.
  • the length of the segments 7 are equal to that of the first layer 5 taken in the longitudinal direction of the axle 1 , and the width of the segments 7 are of uniform 1/n share of the ring constituted by the segments 7, where n is identical to the number of poles 3.
  • the number of the segments 7 is two less than the number of poles 3 in the case of ten or less poles 3 (as shown in Figure 2 for 8 poles 3), or four less than the number of poles 3 in the case of more than ten poles 3, as shown in Figure 1 for 12 poles 3. If the number of poles 3 is odd, the ring constituted by the segments 7 should be split into n shares in such a way that n should be greater by one than the number of poles 3, and then a plurality of segments 7 of length of arch likewise obtained are to be arranged where the plurality of the segments 7 is two less than the number of
  • poles 3 in the case of ten or less poles 3, or four less than the number of
  • poles 3 in the case of more than ten poles 3, as it has been illustrated in Figures 4 and 5.
  • the first layer 5 is also fixed to
  • the first layer 5 is made of ferrite-magnet, while the segments 7 of the second layer 6 are made of steel-magnet.
  • the polarity of the magnets are identified conventionally by S and N in the Figures.
  • Figure 3 shows an embodiment in which a third layer 8 of a single piece is provided between the rotor 4 and the segments 7 of the second layer 6, which has a length equal to those of the groups, and has a width
  • poles of the first layers 5, second layers 6 and third layers 8 in each constituted group are of the same sequence in direction perpendicular to the axle 1 .
  • any synthetic adhesive material can be applied, deposited in about 0.1 mm thickness between the surfaces to be attached.
  • This motor operates similar to the known motors, but yields higher efficiency. This is due partly to the steel-magnet material of the segments 7, and partly to the considerable magnetic field enhancement between the adjacent glued segments 7.
  • the function of barium-ferrite- magnets constituting the first layers 5 and optionally the third layer 8, beyond strengthening the magnetic field, is to prevent demagnetisation of segments 7 in the second layer 6 by draining off eddy currents, which would otherwise demagnetise the steel-magnets.
  • a real motor according to the embodiment in Figure 1 has a working voltage range of 6-80 V, while the load current is 0.01-1 A, and at the peak values the speed is 60,000 rpm.
  • the main advantages of the DC motor according to the invention lies in the higher efficiency than can be produced by the known type motors and in the ability to work within a very wide voltage range.
  • the rotation speed is actually limited only by the quality of the mechanical components.

Abstract

DC motor with brushes, having a rotor (4) comprising an axle (1) and packets of soft-iron lamellas perpendicular to the axle (1) and constituting poles. Wire terminals of coils on the poles are attached to a collector. The rotor is within a cylindrical housing (2) with permanent magnets on its inner surface. These permanent magnets are arranged in at least two layers, where a first layer (5) of a single piece and a second layer (6) of several segments (7) extending parallel to the longitudinal direction of the axle (1) are arranged, and the length of the segments (7) are equal to that of the first layer (5) taken in the longitudinal direction of the axle (1), and the width of the segments (7) are of uniform 1/n share of the ring constituted by the segments (7), where n is identical to the number of poles if that number is even, or is greater by one than the number of poles if that number is odd, and the number of the segments (7) is two less than the number of poles in the case of ten or less poles, or four less than the number of poles in the case of more than ten poles, and the segments (7) are arranged in two groups in axial symmetry where the width of the first layer (5) is defined by the central angle α of the segments (7) attached to each other and to the first layer (5), and the first layer (5) is attached to the inner surface of the housing (2) by adhesive.

Description

DC motor with permanent magnet stator
This invention relates to a DC motor with brushes, having a rotor comprising an axle and packets of soft-iron lamellas perpendicular to the axle and constituting poles, coils of conducting wire are provided on the poles, and the wire terminals are attached to a collector, the rotor is within a cylindrical housing with permanent magnets fastened on its inner surface.
Hungarian patent HU 193 867 disclosed an electric motor with external rotor assembly excited by permanent magnet, in which the rotor forming the outer housing as well has an inner surface on which permanent magnets are fastened, and these magnets are used at the same time to control the motor. Manufacturing the electric motor according to this patent is sophisticated and requires considerable costs. German patent DE 3 807 377 disclosed an enhanced electric motor which comprises magnets in both its rotor and its stator, used together with electromagnets. The combination of magnets and electromagnets is intended to produce enhanced torque.
German patent DE 3 636 376 had as its object to provide a loss- free electric motor. Attaining this aim seemed to be unrealistic. In this embodiment the inventors tried to overcome the troubles with a rotary magnet assembly in which the turning of the permanent magnets to the left and to the right takes place by electromagnets excited through a left run- braking ring and a right run-braking ring. The object of the presented invention is to provide an electric motor of enhanced efficiency which can be manufactured easily by conventional means and constructed of conventional components.
The invention is based on an observation that by attaching distinct layers of magnets to each other, for example by adhesive, one can obtain greater torque, which can further be enhanced when the magnets are combined to ferrite-magnets and steel-magnets, and even further enhance when the steel-magnets are shared into further segments.
The DC motor according to the invention applied with brushes, has a rotor comprising an axle and packets of soft-iron lamellas perpendicular to the axle and constituting poles, coils of conducting wire are provided on the poles, and the wire terminals are attached to a collector. The rotor is within a cylindrical housing with permanent magnets fastened on its inner surface. The permanent magnets are arranged in at least two layers, where a first layer of a single piece and a second layer of several segments extending parallel to the longitudinal direction of the axle are arranged. The length of the segments are equal to that of the first layer taken in the longitudinal direction of the axle, and the width of the segments are of uniform 1/n share of the ring constituted by the segments, where n is identical to the number of poles if that number is even, or is greater by one than the number of poles if that number is odd. The number of the segments is two less than the number of poles in the case of ten or less poles, or four less than the number of poles in the case of more than ten poles. The segments are arranged in two groups in axial symmetry where the width of the first layer is defined by the central angle of the segments attached to each other and to the first layer. The first layer is attached to the inner surface of the housing by adhesive.
Preferably the first layer is made of ferrite-magnet, and the seg- ments of the second layer are made of steel-magnet.
In a preferred embodiment a third layer of a single piece is provided between the rotor and the segments of the second layer, which has a length equal to those of the two groups, has a width defined by the central angle of the segments, made of ferrite-magnet, and attached to the second layer by adhesive.
Advantageously, the poles of the layers in each group are of the same sequence in direction perpendicular to the axle.
Working aspects of the motor according to the invention will be apparent from the description based on the following drawings. Figure 1 shows a cross-section of a motor with a rotor of 12 poles and having groups of magnets in two layers,
Figure 2 shows a cross-section of a motor with a rotor of 8 poles having groups of magnets in two layers,
Figure 3 shows a cross-section of a motor with a rotor of 12 poles having groups of magnets in three layers,
Figure 4 shows a cross-section of a motor with a rotor of 11 poles and having groups of magnets in two layers,
Figure 5 shows a cross-section of a motor with a rotor of 7 poles and having groups of magnets in two layers. The structure of the motors illustrated in the Figures are very similar. Conventional elements, such as rotor 4 and housing 2 of motors well-known from the art are kept in unchanged form, i.e. rotor 4 is constructed of packets of soft-iron lamellas stowed by their plane surface and these packets are mounted perpendicularly to an axle 1. The soft- iron lamellas of the rotor 4 constitute poles 3, onto which coils of conducting wire are provided. In a conventional manner, the wire terminals are attached to a collector. Voltage is applied to the collector through carbon brushes. Housing 2 is made of steel with the axle 1 built on bearings in its centre. The difference between the shown motors and the prior art motors lies in the construction and arrangement of the magnets.
The permanent magnets have been attached by an adhesive or glue to the inner surface of the housing 2, in the height of the soft-iron lamellas of the rotor 4, at least in two layers. The first layer 5 is made of a single piece while the second layer 6 is constructed of several segments 7. The length of the segments 7 are equal to that of the first layer 5 taken in the longitudinal direction of the axle 1 , and the width of the segments 7 are of uniform 1/n share of the ring constituted by the segments 7, where n is identical to the number of poles 3. The number of the segments 7 is two less than the number of poles 3 in the case of ten or less poles 3 (as shown in Figure 2 for 8 poles 3), or four less than the number of poles 3 in the case of more than ten poles 3, as shown in Figure 1 for 12 poles 3. If the number of poles 3 is odd, the ring constituted by the segments 7 should be split into n shares in such a way that n should be greater by one than the number of poles 3, and then a plurality of segments 7 of length of arch likewise obtained are to be arranged where the plurality of the segments 7 is two less than the number of
poles 3 in the case of ten or less poles 3, or four less than the number of
poles 3 in the case of more than ten poles 3, as it has been illustrated in Figures 4 and 5.
It is also apparent from the drawings that magnet segments 7
have been placed fully adjacent to each other in two groups in axial
symmetry, where the width of the first layer 5 is defined by the central
angle ∞ of jointed segments 7 of a group, attached preferably by adhe-
sive to each other and to the first layer 5. The first layer 5 is also fixed to
the inner surface of the housing 2 by adhesive or glue. The first layer 5 is made of ferrite-magnet, while the segments 7 of the second layer 6 are made of steel-magnet. The polarity of the magnets are identified conventionally by S and N in the Figures.
Figure 3 shows an embodiment in which a third layer 8 of a single piece is provided between the rotor 4 and the segments 7 of the second layer 6, which has a length equal to those of the groups, and has a width
defined by the central angle o of the segments 7, made of barium-ferr ite-
magnet, and attached to the second layer 6 by adhesive.
In all embodiments the poles of the first layers 5, second layers 6 and third layers 8 in each constituted group are of the same sequence in direction perpendicular to the axle 1 .
To serve the purpose of adhesive or glue, any synthetic adhesive material can be applied, deposited in about 0.1 mm thickness between the surfaces to be attached. This motor operates similar to the known motors, but yields higher efficiency. This is due partly to the steel-magnet material of the segments 7, and partly to the considerable magnetic field enhancement between the adjacent glued segments 7. The function of barium-ferrite- magnets constituting the first layers 5 and optionally the third layer 8, beyond strengthening the magnetic field, is to prevent demagnetisation of segments 7 in the second layer 6 by draining off eddy currents, which would otherwise demagnetise the steel-magnets. In conclusion the enhanced efficiency is due to the steel-magnet and to its arrangement, and the appropriate effect of the steel-magnet in ensured by the barium- ferrite-magnets. A real motor according to the embodiment in Figure 1 has a working voltage range of 6-80 V, while the load current is 0.01-1 A, and at the peak values the speed is 60,000 rpm.
The main advantages of the DC motor according to the invention lies in the higher efficiency than can be produced by the known type motors and in the ability to work within a very wide voltage range. The rotation speed is actually limited only by the quality of the mechanical components.

Claims

1. DC motor with brushes, having a rotor comprising an axle and packets of soft-iron lamellas perpendicular to the axle and constitut- ing poles, coils of conducting wire are provided on the poles, and the wire terminals are attached to a collector, the rotor is within a cylindrical housing with permanent magnets fastened on its inner surface, characterised in that the permanent magnets are arranged in at least two layers, where a first layer (5) of a single piece and a second layer (6) of several segments (7) extending parallel to the longitudinal direction of the axle (1) are arranged, and the length of the segments (7) are equal to that of the first layer (5) taken in the longitudinal direction of the axle (1), and the width of the segments (7) are of uniform 1/n share of the ring constituted by the segments (7), where n is identical to the number of poles if that number is even, or is greater by one than the number of poles if that number is odd, and the number of the segments (7) is two less than the number of poles in the case of ten or less poles, or four less than the number of poles in the case of more than ten poles, and the segments (7) are arranged in two groups in axial symmetry where
the width of the first layer (5) is defined by the central angle (oc) of the
segments (7) attached to each other and to the first layer (5), and the first layer (5) is attached to the inner surface of the housing (2) by adhesive.
2. The DC motor according to claim 1 , characterised in that the first layer (5) is made of ferrite-magnet, and the segments (7) of the second layer (6) are made of steel-magnet.
3. The DC motor according to claim 1 or 2, characterised in that a third layer (8) of a single piece is provided between the rotor (4) and the segments (7) of the second layer (6), which has a length equal to those of the groups, has a width defined by the central angle (oc) of
the segments (7), made of ferrite-magnet, and attached to the second layer (6) by adhesive.
4. The DC motor according to claim 1 , 2 or 3, characterised in that the poles of the layers (5,6,8) in each group are of the same sequence in direction perpendicular to the axle (1).
PCT/HU1997/000048 1996-09-05 1997-09-05 Dc motor with permanent magnet stator WO1998010505A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU43923/97A AU4392397A (en) 1996-09-05 1997-09-05 Dc motor with permanent magnet stator

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
HUP9602437 1996-09-05
HU9602437A HU218958B (en) 1996-09-06 1996-09-06 Dc electric motor with permanent magnet stator

Publications (1)

Publication Number Publication Date
WO1998010505A1 true WO1998010505A1 (en) 1998-03-12

Family

ID=89994248

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/HU1997/000048 WO1998010505A1 (en) 1996-09-05 1997-09-05 Dc motor with permanent magnet stator

Country Status (3)

Country Link
AU (1) AU4392397A (en)
HU (1) HU218958B (en)
WO (1) WO1998010505A1 (en)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3277324A (en) * 1965-07-21 1966-10-04 Allen Bradley Co Permanent magnet pole piece
US3590293A (en) * 1969-09-29 1971-06-29 Gen Electric Dynamoelectric machine having a stationary assembly of the permanent magnet type
US4023057A (en) * 1974-03-22 1977-05-10 Pacific Textile & Chemical Corporation Electric motor field magnets
DE3245532A1 (en) * 1981-12-21 1983-06-30 Výzkumný a vývojový ústav elektrických stroju točivých, Brno Magnetic circuit of an electrical, rotating, permanent-magnet machine
US4460839A (en) * 1980-06-09 1984-07-17 The Singer Company Magnetic laminae sections for single air gap motor
WO1991007805A1 (en) * 1989-11-14 1991-05-30 The United States Of America, Secretary Of The Army, The Pentagon Permanent magnet structure for use in electric machinery
JPH04355642A (en) * 1991-05-31 1992-12-09 Namiki Precision Jewel Co Ltd Flat vibration motor

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3277324A (en) * 1965-07-21 1966-10-04 Allen Bradley Co Permanent magnet pole piece
US3590293A (en) * 1969-09-29 1971-06-29 Gen Electric Dynamoelectric machine having a stationary assembly of the permanent magnet type
US4023057A (en) * 1974-03-22 1977-05-10 Pacific Textile & Chemical Corporation Electric motor field magnets
US4460839A (en) * 1980-06-09 1984-07-17 The Singer Company Magnetic laminae sections for single air gap motor
DE3245532A1 (en) * 1981-12-21 1983-06-30 Výzkumný a vývojový ústav elektrických stroju točivých, Brno Magnetic circuit of an electrical, rotating, permanent-magnet machine
WO1991007805A1 (en) * 1989-11-14 1991-05-30 The United States Of America, Secretary Of The Army, The Pentagon Permanent magnet structure for use in electric machinery
JPH04355642A (en) * 1991-05-31 1992-12-09 Namiki Precision Jewel Co Ltd Flat vibration motor

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 017, no. 223 (E - 1359) 7 May 1993 (1993-05-07) *

Also Published As

Publication number Publication date
HU218958B (en) 2001-01-29
AU4392397A (en) 1998-03-26
HUP9602437A2 (en) 1997-07-28
HUP9602437A3 (en) 1997-10-28
HU9602437D0 (en) 1996-11-28

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