GB2205451A

GB2205451A - Connecting brush holders and suppression element to stator windings of an electric motor

Info

Publication number: GB2205451A
Application number: GB08811922A
Authority: GB
Inventors: Melle Boer
Original assignee: Philips Gloeilampenfabrieken NV
Current assignee: Koninklijke Philips NV
Priority date: 1987-05-27
Filing date: 1988-05-20
Publication date: 1988-12-07
Anticipated expiration: 2008-05-20
Also published as: BR8802527A; IT8821291V0; GB8811922D0; GB2205451B; FR2616017A3; IT213850Z2; JPS63191860U; JPH0717251Y2; DE3813999A1; NL8701260A; FR2616017B3

Description

22054,51 1 PHN1 2136 ELECTRIC MACHINE The invention reLates to an eLectric

machine, in particuLar an eLectric motor, comprising a stator with stator coiLs, a rotor which is rotatabLe reLative to the stator and which comprises a -oLLector, and a mounting eLement to which carbon brush hoLders with carbon brushes arranged near the coLLector and interference suppression means are secured, which interference-suppression means are connected to first contact members by eLectricaL connection means, which first contact members are eLectricaLLy coupLed to the stator coiLs and are connected to second contact members by eLectricaL connection means which second contact members are eLectricaLLy coupLed to the carbon brushes.

ELectric machines of the type defined in the opening paraqranh are known and are used as eLectric motors in, for exampLe, domestic appLiances such as vacuum cLeaners and kitchen appLiances. The term "coLLector" as used herein is to be understood to mean any device which cooperates with a carbon brush or brushes for the purpose of making an eLectricaL connection to the rotor, for exampLe a commutator or sLip-ring. Such an eLectric motor is shown cliagrammaticaLLy in European Patent ApoLication EP-A-0-096-158. In the known eLectricaL machines the interference suppression means comprise interference-suppression capacitors and/or coiLs. The interference-suppression means are eLectricaLLy connected to the stator windings and the carbon brushes of the motor in conformity with a suitabLe eLectricaL wiring diagram by means of weLds or soLdered joints or by means of crimp contacts or terminaLs. In the eLectric motor discLosed in said Patent AppLication the carbon brush hoLders are provided with terminaLs for the eLectricaL connection of the interference-suppression coiLs to the carbon brushes. Moreoever, the interference-suppression coiLs are eLectricaLLy connected to a distributor pLate by means of cLamping eLements. DeformabLe cLamping means and soLdered joints for connecting interference-suppression means are discLosed in German Patent AppLications 3,236,091 and 3,314,412.

The methods by which the interference-suppression means are 2 PHN12136 mounted in the known eLectricaL machines have the drawback that they cannot readiLy be automated.

It is an object of the invention to improve a machine such as that defined in the opening paragraph in such a way that the necessary interference-suppression eLements can be mounted mechanicaLLy and eLectricaLLy and the carbon brushes can be connected eLectricaLLy with a minimaL number of simpLe operations.

The invention provides an eLectric machine as set forth in the opening paragraph, characterized in that said connection means comprise wire-end portions and the first and the second contact members are pLate-shaped eLectricaL conductors and are each formed with at Least one sLit-Like opening having a scraping portion and a contact portion, the connection means being eLectricaLLy and mechanicaLLy connected to the contact members by inserting the wire-end portions into the sLit-Like openings.

An advantaoe in the production of such an eLectric machine resides in the very simpLe manner in which the machine can be assembLed. Since no auxiLiary equiDment or tooLs, such as for exampLe weLding eLectrocies or oLiers are needec4 to secure the connection means to the contact members, assembLy can be automated to a considerabLe extent without any probLems. Moreover, the production process need not be adapted in order to modify the construction and/or dimensions of the eLectricaL machine to be manufactured.

The carbon brush hoLders may be constructed as cyLindricaL bodies and the second contact members may be integrated with the cyLindricaL bodies. This construction resuLts in a further reduction of the number of parts of the eLectric machine and hence in the production being further simpLified.

The interference-suppression means near each of the carbon brush hoLders may comprise at Least two interference-suppression eLements, incLuding an earthed capacitor and an interference suppression coiL which is eLectricaLLy arranged between the first contact member and the second contact member, in which case the first contact members may each be formed with two sLit-Like 3 PHN12136 openings having a scraping portion and a contact portion, one of said wire-end portions being inserted into each of the two openings, to provide a separate eLectricaL connection to the first contact member for each of the two interference-suppression eLements.

The invention aLso provides a carbon brush hoLder pLate intended for use as a mounting eLement in an eLectric machine as defined in the fourth preceding paragraph, which pLate carries carbon brush hoLders with carbon brushes and interference suppression means eLectricaLLy connected thereto, characterized in that the carbon brush hoLder pLate carries firstcontact members to be eLectricaLLy connected to the stator coiLs of the coLLector machine and second contact members eLectricaLLy connected to the carbon brushes, and in that the contact members are pLate-shaped eLectricaL conductors and are each formed with at Least one sLit-Like opening having a scraping portion and a contact portion, the interference-suppression means and the carbon brushes being eLectricaLLy interconnected by connection means comprising wire-end portions which are eLectricaLLy and mechanicaLLy connected to the contact members by insertion into the sLit-Like openings.

Embodiments of the invention wiLL now be described, by way of exampLe, with reference to the accompanying drawings in which:- Figure 1 shows an eLectric motor in accordance with the invention in a LongitudinaL sectionaL view I-I in (see aLso Fig. 3), Figure 2 shows the eLectric motor of Figure 1 in a LongitudinaL, partLy sectionaL view II-II (see aLso Fiqure 3), Figure 3 shows the eLectric motor of Figure 1 in a cross-sectionaL view III-III (see aLso Figure 1), and Figure 4 shows diagrammticaLLy a part of the eLectric motor of Figure 1.

The eLectric motor shown in the Figures comprises a motor frame comprising two supporting pLates 2 and 4 which are interconnected by four rods 6. SLeeve bearings 8 and 10 are secured in the bearing respectiveLy for rotatabLy journaLLing a 4 PHN12136 motor shaft. The motor shaft 12 carries a rotor comprising a Laminated rotor core 14 on which rotor coiLt 16 are wound. A stator secured to the rods 6 surrounds the rotor and comprises a Laminated stator core 18 and a pLuraLity of stator coiLs 20 arranged on a coiL former. The motor shaft 12, which is axiaLLy supr)orted by means of a thrust bearing 22 mounted in the bearing pLate 4, carries an impeLLer 24 for cooLing the motor in operation.

The motor comprises two carbon brushes 26 and 28 which cooperate with a coLLector 29, for exampLe a commutator or sLip-rings, which is secured to the motor shaft 12 and which is eLectricaLLy connected to the rotor coiLs 16. The carbon brushes 26 and 28 are each sLiclabLy mounted in tubuLar carbon brush hoLders 30 and 32 respectiveLy and are urged against the coLLector 29 by heLicaL springs 34 and 36 respectiveLy. The two brush hoLders 30 and 32 are arranged on a mounting eLement 38 which is secured to the rods 6. Between the mounting eLement 38 and the sLeeve bearing 8 an insuLating spacer 40 is mounted on the motor shaft 12. In addition to said brush hoLders 30 and 32 the mounting eLement IS carries a number of interference-suppression eLements, nameLy an interference-suppression capacitor 42 and an interference-suppression coiL 44 near each of the carbon brush hoLders 30 and 32, said mounting eLement being aLso referred to as carbon brush hoLder pLate.

The interference-suppression capacitors 42 are eLectricaLLy connected to the rods 6 by means of a contact member 46, which is cLamped against the rods 6, and they are connected to contact members 50 by means of eLectricaLLy conducting wires 48 with wire-end portions 48A. The pLate-shaped contact members 50, which are eLectricaLLy connected to the stator coiLs 20, are each formed with two sLit-Like openings 52A and 52B which extend up to one of their edges. The openings 52A and 528 each have an entry portion situated near said edge, an adjoining scraping portion and a contact portion at the cLosed end of the opening. An exampLe of such an opening formed in a contact member is described in the copencling European Patent AppLication EP-A-0 244 017 (PHN 11741; PHN12136 herewith incorporated by reference). The wires 48 and the wire-end portions 48A have a conductive core surrounded by an insulating layer. The wire-end portions 48A are attached to the contact members 50 by insertion into the openings 52A. During insertion the insulatinq sleeve of each wire-end portion is severed in the scraping portion, so that the core makes contact with the contact portion. Obviously, it is also possible to use wires without an insulating sleeve.

The contact members 50 are electrically connected to contact members 56 by means of electrically conducting wires 54 each having two wire-end portions 54A and 549. The contact members 56 are plate-shaped like the contact members 50 but are formed with only one slit-like opening 58. The openings 58 may be given the same shape as the openings 52A and 52B already described. Each of the contact members 56 is mounted on and is inteoral with one of the carbon brush holders 30 and 32. The wire-end portions 54A and 54B of the wires 54 are connected to the respective contact members 50 and 55 by inserting them into the openings 52B and 58 respectively.

The interference-suppression coils 44 used in the motor described herein comprise helical turns 54C of the wires 54 wound on a ferrite element 50.

It is obvious that the scope of the invention is not limited to the embodiment described in the foregoing. For example, for specific uses no interference-suppression coils are needed.

From readinq the present disclosure, other modifications will be apparent to persons skilled in the art. Such modifications may involve other features which are already known in the design and use of electric machines, electrical connectors, and component parts thereof and which may be used instead of or in addition to features already described herein. Although claims have been formulated in this application to particular combinations of features, it should be understood that the scope of the disclosure of the present application also includes any novel feature or any novel combination of features disclosed herein either explicitly or implicitly or any generalisation of one or more of those features 6 PHN12136 which wouLd be obvious to persons skiLLed in the art, whether or not it reLates to the same invention as presentLy cLaimed in any cLaim and whether or not it mitigates any or aLL of the same technicaL probLems as does the present invention. The appLicants hereby give notice that new cLaims may be formuLated to such features and/or combinations of such features during the prosecution of the present appLication or of any further appLication derived therefrom.

7 PHN12136 C Lai m (s) 1. An eLectric machine, in particuLar an eLectric motor, comprising a stator with stator coiLs, a rotor which is rotatabLe reLative to the stator and which comprises a coLLector, and a mounting eLement to which carbon brush hoLders with carbon brushes arranged near the coLLector and interference-suppression means are secured, which interference-suppression means are connected to first contact members by eLectricaL connection means which first contact members are eLectricaLLy coupLed to the stator coiLs and are connected to second contact members by eLectricaL connection means which second contact members are eLectricaLLy coupLed to the carbon brushes, characterized in that said connection means comprise wire-end portions and the first and the second contact members are pLate-shaped eLe'CtricaL conductors and are each formed with at Least one sLit-Like opening having a scraping portion and a contact portion, the connection means being eLectricaLLy and mechanicaLLy connected to the contact members by inserting the wire-end portions into the sLit-Like openings.

2. An eLectric machine as cLaimed in CLaim 1, in which the carbon brush hoLders are constructed as cyLindricaL bodies, characterized in that the second contact members are integrated with the cyLindricaL bodies.

3. An eLectric machine as cLaimed in CLaim 1 or 2, in which the interference-suppression means near each of the carbon brush hoLders comprise at Least two interference-suppression eLements, incLuding an earthed capacitor and an interference-suppression coiL which is eLectricaLLy arranged between the first contact member and the second contact member, characterized in that the first contact members are each formed with two sLit-Like openings having a scraping portion and a contact portion, one of said wire-end portions being inserted in each of the two openings, to provide a separate eLectricaL connection to the first contact member for each of the two interference-suppression eLements.

4. A carbon brush hoLder pLate to be used as a mounting eLement 8 PHN12136 in a machine as cLaimed in CLaim 1, which pLate carries carbon brush hoLders with carbon brushes and interference-suppression means eLectricaLLy connected thereto, characterized in that the carbon brush hoLder pLate carries first contact members to be eLectricaLLy connected to the stator coiLs of the machine and second contact members eLectricaLLy connected to the carbon brushes, and in that the contact members are pLate-shaped eLectricaL conductors and are each formed with at Least one sLit-Like opening having a scraping portion and a contact portion, the interference-suppression means and the carbon brushes being eLectricaLLy interconnected by connection means comprising wire-end portions which are eLectricaLLy and mechanicaLLy connected to the contact members by insertion into the sLit-Like openings.

5. An eLectric machine substantiaLLy as described herein with reference to the accompanying drawings.

6. A carbon brush hoLder pLate substantiaLLy as described herein with reference to the accompanying drawings 7. Any noveL feature or any noveL combination of features discLosed herein.

Published 1988 at The Patent office, state House, 66.71 High Holborn, London WCIR 4TP. Further copies may be obtalned from The Patent Office, Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent. Con. 1/87.