WO2019233596A1 - Electric motor - Google Patents

Electric motor Download PDF

Info

Publication number
WO2019233596A1
WO2019233596A1 PCT/EP2018/065162 EP2018065162W WO2019233596A1 WO 2019233596 A1 WO2019233596 A1 WO 2019233596A1 EP 2018065162 W EP2018065162 W EP 2018065162W WO 2019233596 A1 WO2019233596 A1 WO 2019233596A1
Authority
WO
WIPO (PCT)
Prior art keywords
motor
rotor
stator
electric motor
monolithic
Prior art date
Application number
PCT/EP2018/065162
Other languages
French (fr)
Inventor
Martin Helmis
Original Assignee
Pierburg Pump Technology Gmbh
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 Pierburg Pump Technology Gmbh filed Critical Pierburg Pump Technology Gmbh
Priority to PCT/EP2018/065162 priority Critical patent/WO2019233596A1/en
Publication of WO2019233596A1 publication Critical patent/WO2019233596A1/en

Links

Classifications

    • 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
    • H02K1/27—Rotor cores with permanent magnets
    • H02K1/2706—Inner rotors
    • H02K1/272—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis
    • H02K1/2726—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of a single magnet or two or more axially juxtaposed single magnets
    • H02K1/2733—Annular magnets

Definitions

  • the invention is directed to an electric motor for a motor vehicle, preferably to an electric motor for a motor vehicle auxiliary unit.
  • Electric motors are provided with a rotatable motor rotor and with a static motor stator.
  • the motor rotor is provided permanently magnetized and the motor stator is provided electromagnet!cally magnetized so that no wear-prone sliding contacts are required for energizing the electromagnetic motor stator.
  • the motor stator of this brushless electric motor comprises a stator body with at least one stator coll being electrically energized to provide a stator magnetic field for driving the motor rotor.
  • the permanently magnetized motor rotor can be provided with a monolithic rotor body made of a permanently magnetized resin bonded material, i.e. a permanent magnetic powder being embedded In a resin.
  • the monolithic rotor body is typically directly fixed to a rotor shaft, which allows a compact realization of the motor rotor and, as a result, of the electric motor.
  • the resin bonded material allows only a relatively low magnetic power density so that the electric motor can provide only a low mechanical performance.
  • the permanently magnetized motor rotor can be provided with permanent magnets, for example made of a sintered material, which are embedded into a preferably laminated rotor body.
  • Permanent magnets such as, for example, rare-earth containing alloys allow a significantly higher magnetic power density compared to resin bonded materials.
  • the motor rotor with sintered magnets being embedded into the laminated rotor body allows a high-performance electric motor.
  • the multi-piece motor rotor is relatively large.
  • the electric motor according to the Invention is provided with a permanently magnetized motor rotor defined by a permanently magnetized monolithic rotor body.
  • the monolithic rotor body is directly fixed to a rotor shaft, i.e. the motor rotor Is not provided with any supplemental magnet support body.
  • the motor rotor does not comprise a laminated rotor core. This allows a very compact realization of the motor rotor and, as a result, of the electric motor.
  • the monolithic rotor body is directly cast or sintered onto the rotor shaft. This allows a very strong and reliable fixation of the rotor body at the rotor shaft.
  • the electric motor according to the invention is also provided with a motor stator with a stator body and at least one stator coll.
  • the stator coil Is electrically energized to provide a stator magnetic field for driving the motor rotor.
  • the ferromagnetic stator body can be provided as laminated stator body to minimize eddy currents within the motor stator and, as a result, to allow a high motor efficiency and a high motor power.
  • the monolithic rotor body of the motor rotor is only made of a sintered material.
  • the sintered material can be, for example, a rare-earth containing alloy such as NdFeB.
  • the sintered material can be directly cast onto the rotor body and can be easily permanently magnetized.
  • the sintered material allows a high magnetic power density and, as a result, a high mechanical motor performance of the electric motor.
  • the motor rotor with the monolithic rotor body made of a sintered material allows a compact and high-power electric motor.
  • the monolithic rotor body is a permanently and diametrically magnetized ring magnet with two magnetic poles.
  • the sintered material can be easily manufactured anisotropic to define exactly two diametrical magnetic poles. Since the motor rotor has an annular shape and Is diametrically magnetized, the rotating motor rotor generates a substantially sinusoidal local magnetic field profile, which is detectable at a suitable static sensor position. This allows a very exact detection of the rotor position so that the electric motor can be controlled very accurately and reliably.
  • the monolithic rotor body is coated with a corrosion protection film to avoid a corrosion of the motor rotor even if the motor rotor is in contact with a corrosive fluid.
  • the monolithic rotor body can be, for example, coated with a nickel alloy such as Ni-Cu-Ni.
  • the electric motor according to the invention can be provided to drive an automotive liquid pump, wherein the motor rotor is In fluidic contact with a pump liquid, i.e. the motor rotor is not f!uidically sealed against the pump liquid.
  • the sintered monolithic rotor body according to the invention allows a very compact automotive fluid pump which can provide a high pump output pressure.
  • figure 1 shows a simplified illustration of an automotive liquid pump with an electric motor according to the invention
  • figure 2 shows a schematic sectional view of a motor rotor of the electric motor of figure 1.
  • FIG 1 shows an automotive liquid pump 8 with a brushless electric motor 10, wherein a motor rotor 12 of the electric motor 10 is co- rotatably connected with a pump wheel PW for driving the liquid pump 8,
  • the motor rotor 12 Is in fluidic contact with a pump liquid being pumped by the liquid pump 8.
  • the motor rotor 12 Is fluidically separated from a motor stator 14 by a separating can 15.
  • the motor stator 14 comprises a ferromagnetic stator body 16 and a single stator coil 18 which is arranged satellite-like.
  • the stator coll 18 is electrically connected with a motor electronics 20 for energizing the stator coil 18 for driving the motor rotor 12.
  • the motor rotor 12 comprises a monolithic rotor body 22 being fixed at a rotor shaft 24.
  • the monolithic rotor body 22 is made of a sintered material and is permanently magnetized.
  • the monolithic rotor body 22 is a ring magnet made of IMdFeB which is permanently and diametrically magnetized to define exactly two permanent magnetic poles N,S.
  • the monolithic rotor body 22 is directly cast onto the rotor shaft 24 so that the monolithic rotor body 22 is directly fixed to the rotor shaft 24.
  • the monolithic rotor body 22 is coated with a corrosion protection film 26 made of a nickel alloy.

Abstract

Electric motor (10) for a motor vehicle, comprising a permanently magnetized motor rotor (12) with a monolithic rotor body (22) being directly fixed to a rotor shaft (24), and a motor stator (14) with a stator body (16) and at least one stator coil (18) being electrically energized to provide a stator magnetic field for driving the motor rotor (12), wherein the monolithic rotor body (22) is only made of a sintered material.

Description

Pierburg Pump Technology GmbH, 41460 Neuss
Electric motor
The invention is directed to an electric motor for a motor vehicle, preferably to an electric motor for a motor vehicle auxiliary unit.
Electric motors are provided with a rotatable motor rotor and with a static motor stator. Preferably, the motor rotor is provided permanently magnetized and the motor stator is provided electromagnet!cally magnetized so that no wear-prone sliding contacts are required for energizing the electromagnetic motor stator. The motor stator of this brushless electric motor comprises a stator body with at least one stator coll being electrically energized to provide a stator magnetic field for driving the motor rotor.
The permanently magnetized motor rotor can be provided with a monolithic rotor body made of a permanently magnetized resin bonded material, i.e. a permanent magnetic powder being embedded In a resin. The monolithic rotor body is typically directly fixed to a rotor shaft, which allows a compact realization of the motor rotor and, as a result, of the electric motor. However, the resin bonded material allows only a relatively low magnetic power density so that the electric motor can provide only a low mechanical performance.
Alternatively, the permanently magnetized motor rotor can be provided with permanent magnets, for example made of a sintered material, which are embedded into a preferably laminated rotor body. Sintered materials such as, for example, rare-earth containing alloys allow a significantly higher magnetic power density compared to resin bonded materials. As result, the motor rotor with sintered magnets being embedded into the laminated rotor body allows a high-performance electric motor. However, the multi-piece motor rotor is relatively large.
It is an object of the invention to provide a compact and high-performance electric motor for a motor vehicle.
This object is achieved with an electric motor with the features of claim 1.
The electric motor according to the Invention is provided with a permanently magnetized motor rotor defined by a permanently magnetized monolithic rotor body. The monolithic rotor body is directly fixed to a rotor shaft, i.e. the motor rotor Is not provided with any supplemental magnet support body. In particular, the motor rotor does not comprise a laminated rotor core. This allows a very compact realization of the motor rotor and, as a result, of the electric motor. Preferably, the monolithic rotor body is directly cast or sintered onto the rotor shaft. This allows a very strong and reliable fixation of the rotor body at the rotor shaft. The electric motor according to the invention is also provided with a motor stator with a stator body and at least one stator coll. The stator coil Is electrically energized to provide a stator magnetic field for driving the motor rotor. The ferromagnetic stator body can be provided as laminated stator body to minimize eddy currents within the motor stator and, as a result, to allow a high motor efficiency and a high motor power.
According to the invention, the monolithic rotor body of the motor rotor is only made of a sintered material. The sintered material can be, for example, a rare-earth containing alloy such as NdFeB. The sintered material can be directly cast onto the rotor body and can be easily permanently magnetized. The sintered material allows a high magnetic power density and, as a result, a high mechanical motor performance of the electric motor. As a result, the motor rotor with the monolithic rotor body made of a sintered material allows a compact and high-power electric motor. Preferably, the monolithic rotor body is a permanently and diametrically magnetized ring magnet with two magnetic poles. The sintered material can be easily manufactured anisotropic to define exactly two diametrical magnetic poles. Since the motor rotor has an annular shape and Is diametrically magnetized, the rotating motor rotor generates a substantially sinusoidal local magnetic field profile, which is detectable at a suitable static sensor position. This allows a very exact detection of the rotor position so that the electric motor can be controlled very accurately and reliably. In a preferred embodiment of the invention, the monolithic rotor body is coated with a corrosion protection film to avoid a corrosion of the motor rotor even if the motor rotor is in contact with a corrosive fluid. The monolithic rotor body can be, for example, coated with a nickel alloy such as Ni-Cu-Ni.
The electric motor according to the invention can be provided to drive an automotive liquid pump, wherein the motor rotor is In fluidic contact with a pump liquid, i.e. the motor rotor is not f!uidically sealed against the pump liquid. The sintered monolithic rotor body according to the invention allows a very compact automotive fluid pump which can provide a high pump output pressure.
An embodiment of the invention is described with reference to the enclosed drawings, wherein
figure 1 shows a simplified illustration of an automotive liquid pump with an electric motor according to the invention, and figure 2 shows a schematic sectional view of a motor rotor of the electric motor of figure 1.
Figure 1 shows an automotive liquid pump 8 with a brushless electric motor 10, wherein a motor rotor 12 of the electric motor 10 is co- rotatably connected with a pump wheel PW for driving the liquid pump 8, The motor rotor 12 Is in fluidic contact with a pump liquid being pumped by the liquid pump 8. The motor rotor 12 Is fluidically separated from a motor stator 14 by a separating can 15.
The motor stator 14 comprises a ferromagnetic stator body 16 and a single stator coil 18 which is arranged satellite-like. The stator coll 18 is electrically connected with a motor electronics 20 for energizing the stator coil 18 for driving the motor rotor 12.
The motor rotor 12 comprises a monolithic rotor body 22 being fixed at a rotor shaft 24. The monolithic rotor body 22 is made of a sintered material and is permanently magnetized. In the present embodiment of the Invention the monolithic rotor body 22 is a ring magnet made of IMdFeB which is permanently and diametrically magnetized to define exactly two permanent magnetic poles N,S. The monolithic rotor body 22 is directly cast onto the rotor shaft 24 so that the monolithic rotor body 22 is directly fixed to the rotor shaft 24. In the present embodiment of the invention, the monolithic rotor body 22 is coated with a corrosion protection film 26 made of a nickel alloy. Reference list
8 automotive liquid pump
10 electric motor
12 motor rotor
14 motor stator
15 separating can
16 stator body
18 stator coil
20 motor electronics
22 monolithic rotor body
24 rotor shaft
26 corrosion protection film
PW pump wheel

Claims

1. Electric motor (10) for a motor vehicle, comprising
a permanently magnetized motor rotor (12) with a monolithic rotor body (22) being directly fixed to a rotor shaft (24), and
a motor stator (14) with a stator body (16) and at least one stator coil (18) being electrically energized to provide a stator magnetic field for driving the motor rotor (12),
wherein the monolithic rotor body (22) is only made of a sintered material, , Electric motor according (10) to claim 1, wherein the monolithic rotor body (22) is a permanently and diametrically magnetized ring magnet with two magnetic poles (N,S). , Electric motor according (10) to any preceding claim, wherein the monolithic rotor body (22) is coated with a corrosion protection film
(26) , Automotive liquid pump (8) with an electric motor (10) according to any preceding claim, wherein the motor rotor (12) is In fluidic contact with a pump liquid.
PCT/EP2018/065162 2018-06-08 2018-06-08 Electric motor WO2019233596A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/EP2018/065162 WO2019233596A1 (en) 2018-06-08 2018-06-08 Electric motor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2018/065162 WO2019233596A1 (en) 2018-06-08 2018-06-08 Electric motor

Publications (1)

Publication Number Publication Date
WO2019233596A1 true WO2019233596A1 (en) 2019-12-12

Family

ID=62599583

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2018/065162 WO2019233596A1 (en) 2018-06-08 2018-06-08 Electric motor

Country Status (1)

Country Link
WO (1) WO2019233596A1 (en)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3858308A (en) * 1973-06-22 1975-01-07 Bendix Corp Process for making a rotor assembly
US4948999A (en) * 1981-05-21 1990-08-14 U.S. Philips Corporation Self-starting two-pole single-phase synchronous motor
DE4111411A1 (en) * 1991-04-09 1992-10-15 Papst Motoren Gmbh & Co Kg High speed electric motor rotor with protective cover and contg. breakable components - has cover formed as screw spring of draw type with windings in untensioned state locating against each other or spaced apart
US5611679A (en) * 1996-04-22 1997-03-18 Eastman Kodak Company Corrosion-resistant pump
US20090001826A1 (en) * 2007-06-26 2009-01-01 Yuzuru Suzuki Rotor structure
WO2015131948A1 (en) * 2014-03-06 2015-09-11 Pierburg Pump Technology Gmbh Automotive electric liquid pump
US20170305676A1 (en) * 2016-04-25 2017-10-26 Kamran Ramezani Motor shaped as a roller

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3858308A (en) * 1973-06-22 1975-01-07 Bendix Corp Process for making a rotor assembly
US4948999A (en) * 1981-05-21 1990-08-14 U.S. Philips Corporation Self-starting two-pole single-phase synchronous motor
DE4111411A1 (en) * 1991-04-09 1992-10-15 Papst Motoren Gmbh & Co Kg High speed electric motor rotor with protective cover and contg. breakable components - has cover formed as screw spring of draw type with windings in untensioned state locating against each other or spaced apart
US5611679A (en) * 1996-04-22 1997-03-18 Eastman Kodak Company Corrosion-resistant pump
US20090001826A1 (en) * 2007-06-26 2009-01-01 Yuzuru Suzuki Rotor structure
WO2015131948A1 (en) * 2014-03-06 2015-09-11 Pierburg Pump Technology Gmbh Automotive electric liquid pump
US20170305676A1 (en) * 2016-04-25 2017-10-26 Kamran Ramezani Motor shaped as a roller

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