GB1591560A - Electric machine - Google Patents

Electric machine Download PDF

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Publication number
GB1591560A
GB1591560A GB23930/78A GB2393078A GB1591560A GB 1591560 A GB1591560 A GB 1591560A GB 23930/78 A GB23930/78 A GB 23930/78A GB 2393078 A GB2393078 A GB 2393078A GB 1591560 A GB1591560 A GB 1591560A
Authority
GB
United Kingdom
Prior art keywords
layer
bearing
alumina
bore
machine
Prior art date
Legal status (The legal status 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 status listed.)
Expired
Application number
GB23930/78A
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.)
Heemaf BV
Heemaf NV
Original Assignee
Heemaf BV
Heemaf NV
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 Heemaf BV, Heemaf NV filed Critical Heemaf BV
Publication of GB1591560A publication Critical patent/GB1591560A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K5/00—Casings; Enclosures; Supports
    • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
    • H02K5/16—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields
    • H02K5/173—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields using bearings with rolling contact, e.g. ball bearings
    • H02K5/1732—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields using bearings with rolling contact, e.g. ball bearings radially supporting the rotary shaft at both ends of the rotor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C35/00—Rigid support of bearing units; Housings, e.g. caps, covers
    • F16C35/04—Rigid support of bearing units; Housings, e.g. caps, covers in the case of ball or roller bearings
    • F16C35/042—Housings for rolling element bearings for rotary movement
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C35/00—Rigid support of bearing units; Housings, e.g. caps, covers
    • F16C35/04—Rigid support of bearing units; Housings, e.g. caps, covers in the case of ball or roller bearings
    • F16C35/06—Mounting or dismounting of ball or roller bearings; Fixing them onto shaft or in housing
    • F16C35/07—Fixing them on the shaft or housing with interposition of an element
    • F16C35/077—Fixing them on the shaft or housing with interposition of an element between housing and outer race ring
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C19/00—Bearings with rolling contact, for exclusively rotary movement
    • F16C19/02—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows
    • F16C19/04—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for radial load mainly
    • F16C19/06—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for radial load mainly with a single row or balls
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2204/00—Metallic materials; Alloys
    • F16C2204/20—Alloys based on aluminium
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2206/00—Materials with ceramics, cermets, hard carbon or similar non-metallic hard materials as main constituents
    • F16C2206/40—Ceramics, e.g. carbides, nitrides, oxides, borides of a metal
    • F16C2206/42—Ceramics, e.g. carbides, nitrides, oxides, borides of a metal based on ceramic oxides
    • F16C2206/44—Ceramics, e.g. carbides, nitrides, oxides, borides of a metal based on ceramic oxides based on aluminium oxide (Al2O3)
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2208/00—Plastics; Synthetic resins, e.g. rubbers
    • F16C2208/02—Plastics; Synthetic resins, e.g. rubbers comprising fillers, fibres
    • F16C2208/04—Glass fibres
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2208/00—Plastics; Synthetic resins, e.g. rubbers
    • F16C2208/80—Thermosetting resins
    • F16C2208/86—Epoxy resins
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2240/00—Specified values or numerical ranges of parameters; Relations between them
    • F16C2240/40—Linear dimensions, e.g. length, radius, thickness, gap
    • F16C2240/60—Thickness, e.g. thickness of coatings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2380/00—Electrical apparatus
    • F16C2380/26—Dynamo-electric machines or combinations therewith, e.g. electro-motors and generators

Description

(54) ELECTRIC MACHINE (71) We, HEEMAF B.V. of No. 5, Bornsestraat, Hengelo, The Netherlands a private limited liability company organized under the Laws of the Netherlands, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to an electric machine comprising a stator and a rotor, the rotor shaft being supported by bearings disposed in bearing bores in a housing of the machine and at least one of the bearings being electrically insulated from its bore.
Without the insulation, the induced electric voltage may cause a current flow through the closed circuit formed by the shaft, the bearings and the housing, the value of which may be so high that, for example, the bearings may be damaged or a risk of explosion is involved.
In accordance with the invention the bore is coated with an intermediate aluminiumnickel layer and an alumina insulating layer overlies the intermediate layer.
The invention will be described more fully with reference to an embodiment shown in the drawings.
In the drawings Figure 1 is a longitudinal sectional view of an electric machine embodying the invention, Figure 2 is a longitudinal sectional view of a detail of Figure 1, Figures 3, 4 and 5 illustrate details showing the various steps of the method of the invention.
The electric machine 1 comprises a stator 2 and a rotor 3. The stator includes a field winding 4. The electric machine may be of any type, for example, a three-phase machine, in which case three connections 5, 6 and 7 are provided. The rotor shaft 8 is journalled on each side in bearings 9 and 10 respectively. The bearing shield 11 (see Figure 2) has a bore 12 to receive the ball bearing 13. The ball bearing 13 comprises two bearing rings 14 and 15, between which balls for example 16, are arranged. In the bearing bore is provided a layer of insulating material i.e. alumina Ate3. The bearing ring 14 is enclosed in an axial direction between two insulating rings 18 and 19 respectively of epoxy glass fibre. The bearing is accomodated in a conventional manner in the housing of the machine.
The bearing is preferably insulated on the non-driving side as well as on the driving side in order to exclude even the possibility of a completed circuit across the driven tool.
After the bearing bore (see Figure 3) has been machined to the correct size, an aluminium-nickel layer (see Figure 4) is applied by spraying to the steel of the bearing bore to serve as an adhesive layer. Onto the aluminium-nickel layer is sprayed in the form of plasma a layer 20 of alumina A1203. The alumina is processed to the form of a plasma by ionisation of A1203 powder in a welding arc. Subsequently the porous alumina is finished by grinding so that the bearing bore 21 (see Figure 5) is obtained. In a last step the whole bearing bore is impregnated with epoxy resin lacquer free of solvents in order to avoid porosity of the resin layer. The adhesive aluminium-nickel layer may have a thickness of 0.1 mm, whereas the nominal thickness of the alumina is 0.3 mm. The nominal thickness of the epoxy glass fibre rings amount to 2 mms.
WHAT WE CLAIM IS: 1. An electric machine comprising a stator and a rotor, the rotor shaft being supported by bearings disposed in bearing bores in a housing of the machine and at least one of the bearings being electrically insulated from its bore wherein the bore is coated with an intermediate aluminium-nickel layer and
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. (54) ELECTRIC MACHINE (71) We, HEEMAF B.V. of No. 5, Bornsestraat, Hengelo, The Netherlands a private limited liability company organized under the Laws of the Netherlands, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to an electric machine comprising a stator and a rotor, the rotor shaft being supported by bearings disposed in bearing bores in a housing of the machine and at least one of the bearings being electrically insulated from its bore. Without the insulation, the induced electric voltage may cause a current flow through the closed circuit formed by the shaft, the bearings and the housing, the value of which may be so high that, for example, the bearings may be damaged or a risk of explosion is involved. In accordance with the invention the bore is coated with an intermediate aluminiumnickel layer and an alumina insulating layer overlies the intermediate layer. The invention will be described more fully with reference to an embodiment shown in the drawings. In the drawings Figure 1 is a longitudinal sectional view of an electric machine embodying the invention, Figure 2 is a longitudinal sectional view of a detail of Figure 1, Figures 3, 4 and 5 illustrate details showing the various steps of the method of the invention. The electric machine 1 comprises a stator 2 and a rotor 3. The stator includes a field winding 4. The electric machine may be of any type, for example, a three-phase machine, in which case three connections 5, 6 and 7 are provided. The rotor shaft 8 is journalled on each side in bearings 9 and 10 respectively. The bearing shield 11 (see Figure 2) has a bore 12 to receive the ball bearing 13. The ball bearing 13 comprises two bearing rings 14 and 15, between which balls for example 16, are arranged. In the bearing bore is provided a layer of insulating material i.e. alumina Ate3. The bearing ring 14 is enclosed in an axial direction between two insulating rings 18 and 19 respectively of epoxy glass fibre. The bearing is accomodated in a conventional manner in the housing of the machine. The bearing is preferably insulated on the non-driving side as well as on the driving side in order to exclude even the possibility of a completed circuit across the driven tool. After the bearing bore (see Figure 3) has been machined to the correct size, an aluminium-nickel layer (see Figure 4) is applied by spraying to the steel of the bearing bore to serve as an adhesive layer. Onto the aluminium-nickel layer is sprayed in the form of plasma a layer 20 of alumina A1203. The alumina is processed to the form of a plasma by ionisation of A1203 powder in a welding arc. Subsequently the porous alumina is finished by grinding so that the bearing bore 21 (see Figure 5) is obtained. In a last step the whole bearing bore is impregnated with epoxy resin lacquer free of solvents in order to avoid porosity of the resin layer. The adhesive aluminium-nickel layer may have a thickness of 0.1 mm, whereas the nominal thickness of the alumina is 0.3 mm. The nominal thickness of the epoxy glass fibre rings amount to 2 mms. WHAT WE CLAIM IS:
1. An electric machine comprising a stator and a rotor, the rotor shaft being supported by bearings disposed in bearing bores in a housing of the machine and at least one of the bearings being electrically insulated from its bore wherein the bore is coated with an intermediate aluminium-nickel layer and an alumina insulating layer overlies the intermediate layer.
2. A machine as claimed in claim I in which the alumina layer is impregnated with epoxy resin.
3. A machine as claimed in claim I or 2 in which both bearings are insulated from their bores by alumina layers overlying aluminium-nickel intermediate layers.
4. A machine as claimed in any of claims I to 3 in which the or each bearing is held in position axially by way of rings of glass-fibrereinforced epoxy resin.
5. A method of forming the electricallyinsulating layer in the machine of claim I in which a coating of aluminium-nickel is sprayed onto the bearing bore and the alumina layer is applied to the coating by plasma spraying.
6. A method as claimed in claim 5 in which the alumina layer is finished by grinding.
7. A method as claimed in claim 6 in which after grinding the alumina layer is impregnated with solvent-free epoxy resin lacquer.
8. An electric machine having insulating bearings substantially as described with reference to the accompanying drawing.
9. A method of applying a layer of alumina to a bearing bore in a housing of an electric machine substantially as described with reference to the accompanying drawing.
GB23930/78A 1977-11-22 1978-05-30 Electric machine Expired GB1591560A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL7712871A NL7712871A (en) 1977-11-22 1977-11-22 ELECTRIC MACHINE.

Publications (1)

Publication Number Publication Date
GB1591560A true GB1591560A (en) 1981-06-24

Family

ID=19829582

Family Applications (1)

Application Number Title Priority Date Filing Date
GB23930/78A Expired GB1591560A (en) 1977-11-22 1978-05-30 Electric machine

Country Status (2)

Country Link
GB (1) GB1591560A (en)
NL (1) NL7712871A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0068062A1 (en) * 1981-06-30 1983-01-05 Siemens-Allis, Inc. Insulated bearing for an electrical machine
GB2231447A (en) * 1989-05-10 1990-11-14 Mitsubishi Electric Corp Insulated bearing assembly in a traction motor for electric rolling stock
GB2275372A (en) * 1993-02-22 1994-08-24 Yang Tai Her Stator structure for electric motor
DE102016202399A1 (en) 2015-02-17 2016-08-18 Aktiebolaget Skf Electrically insulated bearing
US10823229B2 (en) 2017-03-24 2020-11-03 Aktiebolaget Skf Rolling-element bearing including an electrically insulating layer

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0068062A1 (en) * 1981-06-30 1983-01-05 Siemens-Allis, Inc. Insulated bearing for an electrical machine
GB2231447A (en) * 1989-05-10 1990-11-14 Mitsubishi Electric Corp Insulated bearing assembly in a traction motor for electric rolling stock
GB2231447B (en) * 1989-05-10 1993-08-25 Mitsubishi Electric Corp Improvements in or relating to running gear for an electric rolling stock
GB2275372A (en) * 1993-02-22 1994-08-24 Yang Tai Her Stator structure for electric motor
DE102016202399A1 (en) 2015-02-17 2016-08-18 Aktiebolaget Skf Electrically insulated bearing
US9850951B2 (en) 2015-02-17 2017-12-26 Aktiebolaget Skf Electrical insulated bearing
US10823229B2 (en) 2017-03-24 2020-11-03 Aktiebolaget Skf Rolling-element bearing including an electrically insulating layer

Also Published As

Publication number Publication date
NL7712871A (en) 1979-05-25

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Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee