EP0644097B1 - A current return assembly for railway traction and brushes therefor - Google Patents

A current return assembly for railway traction and brushes therefor Download PDF

Info

Publication number
EP0644097B1
EP0644097B1 EP94202585A EP94202585A EP0644097B1 EP 0644097 B1 EP0644097 B1 EP 0644097B1 EP 94202585 A EP94202585 A EP 94202585A EP 94202585 A EP94202585 A EP 94202585A EP 0644097 B1 EP0644097 B1 EP 0644097B1
Authority
EP
European Patent Office
Prior art keywords
brush
wedge
conductive body
contact surface
engagement
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 - Lifetime
Application number
EP94202585A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0644097A1 (en
Inventor
Romualdo Vigorelli
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.)
RISOMESA SpA
Original Assignee
RISOMESA SpA
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 RISOMESA SpA filed Critical RISOMESA SpA
Publication of EP0644097A1 publication Critical patent/EP0644097A1/en
Application granted granted Critical
Publication of EP0644097B1 publication Critical patent/EP0644097B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B61—RAILWAYS
    • B61F—RAIL VEHICLE SUSPENSIONS, e.g. UNDERFRAMES, BOGIES OR ARRANGEMENTS OF WHEEL AXLES; RAIL VEHICLES FOR USE ON TRACKS OF DIFFERENT WIDTH; PREVENTING DERAILING OF RAIL VEHICLES; WHEEL GUARDS, OBSTRUCTION REMOVERS OR THE LIKE FOR RAIL VEHICLES
    • B61F15/00—Axle-boxes
    • B61F15/20—Details
    • B61F15/28—Axle-boxes modified to ensure electrical conductivity

Definitions

  • the present invention relates to a current return assembly for railway traction, and to brushes therefor.
  • This return path should be able to carry, with but minimal voltage drops, currents of high intensity, on the order of 2000 to 3000A, which must not be flowed through the bearings of wheel-carrying axles to which the wheels are keyed.
  • current return assemblies are mounted on the bogies of electric locomotives which can transfer, by means of electric contact brushes housed slidably in sockets of a brush holder body, electric current to the end of the axle through a collector which comprises a contact cap of bronze secured on the axle end.
  • each return path should be capable of transferring large currents in the 500 to 600A range, usually split among several brushes.
  • the return assemblies should be mechanically robust and easy to take down for inspection and servicing.
  • the life allowance of the brushes should be quite long and ensure a coverage of no less than one million kilometers, in order to cut the inspection and maintenance operations down to a minimum.
  • the brushes should have high electric conductivity, minimal contact loss, and a minimal frictional coefficient.
  • the whole of the return assemblies should be capable of withstanding the multivarious adverse actions of their environment: varying temperature and moisture, weather and saline agents, dirt, sand, external shocks, etc.
  • the brush pressure should be held within an optimum range.
  • brush wear is due essentially to two components: an electrical component which causes wear at an inversely varying rate with the contact pressure, and a mechanical component which is substantially proportional to the contact pressure.
  • the optimum range is 100 to 200 g/cm 2 for the contact pressures.
  • a reduction in the mass/weight of the brushes enables, for the same anticipated acceleration stresses, the required contact pressure to be reduced to approach the optimum conditions, thereby reducing wear, the range of variability of the contact pressure due to vibrations, and ultimately improving the service life of the brushes.
  • a reduction in the mass/weight of the brushes also affects the housings, which become less stressed by the brushes striking the walls and can, therefore, be sized accordingly to save material, and in the extreme, with the adoption for the housings of construction materials which are less strong mechanically but much lighter in weight.
  • the brush holder assemblies being thus lightened, will stress the anchoring members and supporting structures to a lesser extent, such that these can be, in turn, made lighter or operated under conditions of improved safety.
  • the present invention has for its subject-matter a current return assembly for railway traction and brushes therefor, which solves the problems and achieves the benefits indicated, while conforming to regulations and standards imposed by railway agencies, that is without requiring structural and dimensional changes of the assembly support and other members of the electric locomotive bogie.
  • the brushes thus lightened, can be used in a return assembly which, being benefited by the lower stresses brought into play, is constructed from light alloy and allows anchoring on conventional supports by anchor members (studs and nuts) which are much less stressed, to the advantage of safety, reduction of the fastening torques, and consequently of ease of assembly and disassembly for maintenance and servicing operations.
  • a brush constructed in accordance with the present invention comprises a conductive body 1, having the shape of a right parallelepipedon, with a base of width L, tangential thickness ST and height H1.
  • the tangential thickness ST corresponds to the relative sliding direction provided for the brush.
  • the conductive body consists of metalgraphite, a sintered compound of copper/graphite, preferably to a ratio of 87%, 13% by weight.
  • This material has a high electric conductivity, low contact voltage drop on the order of 0.7 volts, low friction coefficient owing to its graphite content, and high resistance to wear which makes it preferable compared to graphite and electrographite.
  • this material has, compared to graphite, a high specific density of 5.2 g per cm 2 , approximately three times as high as that of graphite-based materials.
  • the height of a brush be greater than the tangential thickness, even when the brush is worn.
  • the height of the conductive body H1 is less, e.g. 35 mm, the necessary brush height being achieved with a small plate 2 of a light material which fits on top of the conductive body 1.
  • the plate 2 in the shape of a right parallelepipedon with the same dimensions L and ST as those of the body 1, has a height H2 such that the two elements coupled together form a brush of adequate height but much lighter weight.
  • the height H2 may be 10 mm, for example.
  • the material comprising the plate 2 may be selected from a broad spectrum and is preferably bakelized cloth, easy to work, but may be plastics materials, comparatively resilient, such as ABS, DELRIN, NYLON or silicon rubbers, which can be worked mechanically or formed in a mold.
  • the upper face of the conductive body 1, opposite from the contact and rubbing surface 3 of the brush, has a wedge-shaped recess with a corner edge 4 parallel with the larger dimension of the contact surface 3 and a spread angle on the order of 130-150°.
  • the plate 2 has, in turn, an engagement wedge 5 mating with the wedge-shaped recess.
  • the opposite face of the plate 2 from the engagement wedge 5 has an undercut 6 in the shape of a cylinder segment for housing a constant pressure spring therein which applies a thrust force F.
  • the undercut 6 ensures thrust centering on the brush.
  • the orientation of the wedge-shaped recess and the corresponding engagement wedge which is shown here parallel with the larger dimension of the contact surface, is preferably but not necessarily perpendicular to the relative sliding direction between the brush and the collector, and hence to the tangential thickness ST, so as to avoid even small relative movements between the conductive body 1 and the plate 2 in the sliding direction, with displacements of the point of application of the thrust F.
  • the relative sliding direction may not be coincident with the thickness or the width of the brush and may largely depart therefrom.
  • the plate 2 is also provided with two cylindrical through-holes 7, 8 aligned to corresponding cylindrical sockets 9, 10 open on the upper face of the conductive body for the insertion of two copper braids 11, 12 which ensure the electric connection of the brush to a brush holder body.
  • the ends of the copper braids 11, 12 are secured in the sockets 9 and 10 by soldering with a tin alloy, preferably introduced into the sockets 9 and 10 through two gates 9A and 10A, respectively, open on a side wall of the conductive body and communicated to the sockets 9 and 10.
  • the depth of the sockets 9 and 10 can be limited to a few millimeters, on the order of ten mm, thereby increasing the useful height of the conductive body which may be raised to 25 mm.
  • the braid ends can be first forced into copper bushes which are inserted into the sockets 9 and 10.
  • a conductive brush is obtained which ensures maximum operation reliability and uniform wear, with a reduced weight equal illustratively to 80% of a brush of the same size and material.
  • a further reduction in weight can be obtained by providing, in the body 1, a wedge-shaped undercut 13 disposed between the two openings 9, 10 with the apical corner edge perpendicular to the larger base dimension L.
  • a brush having the dimensions indicated and constructed in accordance with the present invention has a weight/mass of about 150 g and when subjected to an acceleration of 20 g generates a thrust force of 3 kg.
  • the operative thrust/reaction conditions between the brush and the commutator will vary from a minimum of 0.2 kg to a maximum of 6.2 kg, which correspond to a contact pressure of 25 to 780 g per cm 2 at an average pressure of 400 g per cm 2 when the brush is not subjected to accelerations.
  • a conventional brush with the same dimensions and of the same material would be unable to operate properly due to the inertial forces (3.8 kg) prevailing over the contact force F.
  • the contact pressure range would be quite wide, between 0 and 875 g/cm 2 , and consequently the brush would be subjected to a fast rate of wear due to the electrical component in a condition of zero contact pressure and to the mechanical component in a condition of maximum contact pressure.
  • the brush comprises a conductive body 40 of metalgraphite having the shape of a right parallelepipedon with a height H4, width L and tangential thickness ST.
  • the body 40 is provided in opposition with the contact surface 41 with a turret 42, having a height H5, terminated at the top with a wedge-shaped recess, similar to the one shown in Figure 1.
  • the turret 42 has a width L2 which is suitably less than L, e.g. equal to 1/2L, and is through-penetrated by a cylindrical socket 43, with its axis parallel with the width L and a diameter appropriate to receive an electric connection braid 45, possibly equipped with a copper bush 44, also housed in the socket 43.
  • the braid 45 and the bush 44 are soldered on the conductive body by pouring a low melt alloy into the socket 43 through a conical gate 46 open on a face of the turret and communicated to the socket 43.
  • the bush 44 where provided, is drilled at the gate to admit the molten alloy flow to the braid 45.
  • the turret 42 is overlaid by a small plate 46 of a lightweight material (bakelized cloth) having the same width and tangential thickness as the body 40.
  • the plate 46 has a height H6 such that the coupling of the plate 46 to the conductive body 40 will form a brush of greater height, even when the body is worn, than the tangential thickness of the brush.
  • the plate 46 For proper coupling of the plate 46 and the body 40, or more appropriately, the turret 42, the plate 46 has an engagement wedge 47 mating with the wedge-shaped recess of the turret and being flanked in the apex direction of the wedge by two teeth 48, 49 which embrace the turret 42.
  • the plate is through-penetrated by two cylindrical holes 50, 51 perpendicular to the contact surface of the brush, for the insertion of the two legs of the braid 45 which come out of the socket 42, and has an undercut 52 in the shape of a cylinder segment on the opposite face from the engagement wedge 47.
  • the weight of a brush thus constructed is also on the order of 150 g.
  • the weight of a current return assembly so constructed is practically halved with respect to a corresponding assembly with the body made of steel.
  • Figures 5 and 6 show, respectively in plan view and in section, a preferred embodiment of a current return assembly.
  • the assembly comprises a flanged brush holder body 15 forming a tern of prismatic housings 16, 17, 18 distributed circumferentially around a central axis 161 for housing a tern of brushes like those already described and a tern of elastic U-shaped anchors (one of which 19 is shown) provided with hooking teeth, removable by bringing the free ends near, which support and secure in place a tern of constant pressure coil springs, one of which 20 is shown.
  • the flange of the body 15, having two opposite flat annular surfaces for coupling to a support and a closure cap, respectively, is provided with expansions with bosses 21, 22, 23 forming seats for corresponding anchor studs, and with an arm 24 provided with openings for securing terminals of electric connection braids.
  • threaded sockets 25, 26, 27 are provided for the clamping by means of screws, such as 30, of terminals of the electric connection braids of the brushes, so that the current return is ensured from the electrical apparatus to the brush holder body by means of a first aggregate of conductive braids, from the brush holder body to the brushes by means of a second set of braids, then from the latter to the axle end and thence to the rail.
  • this is suitably insulated electrically from its support and the fastening members, nut 31, stud 32, by an insulating gasket 28 and insulating bushes such as 33 to prevent current flows, even partial ones, to the support and the axle bearings contained therein.
  • the gasket 28 also ensures the sealing off of the brush housing to the axle end, avoiding the infiltration of dust and elements which could impair the functionality of the brushes.
  • the cap 29 is also a light alloy casting, peferably a self-hardening aluminum alloy, identified by Code GD-AlSi12 of UNI 5076 Standard.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Motor Or Generator Current Collectors (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)
  • Current-Collector Devices For Electrically Propelled Vehicles (AREA)
  • Control Of Direct Current Motors (AREA)
EP94202585A 1993-09-16 1994-09-08 A current return assembly for railway traction and brushes therefor Expired - Lifetime EP0644097B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITMI931998A IT1272642B (it) 1993-09-16 1993-09-16 Gruppo di ritorno corrente per tradizione ferroviaria e relative spazzole
ITMI931998 1993-09-16

Publications (2)

Publication Number Publication Date
EP0644097A1 EP0644097A1 (en) 1995-03-22
EP0644097B1 true EP0644097B1 (en) 1997-02-26

Family

ID=11366908

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94202585A Expired - Lifetime EP0644097B1 (en) 1993-09-16 1994-09-08 A current return assembly for railway traction and brushes therefor

Country Status (5)

Country Link
EP (1) EP0644097B1 (it)
AT (1) ATE149124T1 (it)
DE (1) DE69401796T2 (it)
ES (1) ES2098862T3 (it)
IT (1) IT1272642B (it)

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB556465A (en) * 1942-03-02 1943-10-06 Morgan Crucible Co Improvements in or relating to electric current collecting brushes or the like
FR2616731B1 (fr) * 1987-06-22 1989-11-17 Ferraz Dispositif de retour de courant pour vehicules sur rails
JPH05190240A (ja) * 1992-01-13 1993-07-30 Mitsui Mining & Smelting Co Ltd 電刷子の製造方法及び電刷子製造用銅粉原料

Also Published As

Publication number Publication date
ITMI931998A0 (it) 1993-09-16
IT1272642B (it) 1997-06-26
DE69401796D1 (de) 1997-04-03
ATE149124T1 (de) 1997-03-15
EP0644097A1 (en) 1995-03-22
ES2098862T3 (es) 1997-05-01
DE69401796T2 (de) 1997-07-03
ITMI931998A1 (it) 1995-03-16

Similar Documents

Publication Publication Date Title
US7365470B1 (en) Brush holder assemblies including brush holders with handles
PL166980B1 (pl) Maszyna elektryczna pradu stalego PL PL PL
EP0305991A1 (en) Starting electric motor
EP0644097B1 (en) A current return assembly for railway traction and brushes therefor
US5915306A (en) Generator mounting assembly
US5825110A (en) Bracket support with floating bearing for fractional horsepower motor
US4573275A (en) Arrangement for the mounting of measuring devices of axle measurement equipments
KR100328558B1 (ko) 경량전철용 집전기
US2894239A (en) Brush mechanism
US917188A (en) Dynamo-electric machine.
KR100328559B1 (ko) 경량전철용 집전기
US2313916A (en) Generator and mounting means therefor
US2343693A (en) Current collecting apparatus
CN112701844B (zh) 轴端发电装置及铁路车辆
US3609628A (en) Current-transmitting devices for the axles of electric railway vehicles
US534977A (en) Electric brake
SU1105966A1 (ru) Щеткодержатель дл электрической машины
KR910002394Y1 (ko) 철도차량의 아답터취부형 축상자
US3556312A (en) Car coupler
CN113904188B (zh) 一种铁路货车轴承接地装置
US2558709A (en) Wear shoe for railroad equalizer truck frames
US930864A (en) Brush-holding stud.
KR200369577Y1 (ko) 전동차용 집전장치의 마찰판 고정장치
KR200160586Y1 (ko) 전동차의 고정접촉자부용 판스프링
US1773192A (en) Section insulator

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT CH DE ES FR GB LI

17P Request for examination filed

Effective date: 19950207

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

17Q First examination report despatched

Effective date: 19960621

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT CH DE ES FR GB LI

REF Corresponds to:

Ref document number: 149124

Country of ref document: AT

Date of ref document: 19970315

Kind code of ref document: T

REG Reference to a national code

Ref country code: CH

Ref legal event code: NV

Representative=s name: JACOBACCI & PERANI S.A.

Ref country code: CH

Ref legal event code: EP

ET Fr: translation filed
REF Corresponds to:

Ref document number: 69401796

Country of ref document: DE

Date of ref document: 19970403

REG Reference to a national code

Ref country code: ES

Ref legal event code: FG2A

Ref document number: 2098862

Country of ref document: ES

Kind code of ref document: T3

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: ES

Payment date: 20020802

Year of fee payment: 9

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 20020808

Year of fee payment: 9

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20020815

Year of fee payment: 9

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 20020819

Year of fee payment: 9

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20020822

Year of fee payment: 9

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20020930

Year of fee payment: 9

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20030908

Ref country code: AT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20030908

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20030910

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20030930

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20030930

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20040401

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20030908

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20040528

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

REG Reference to a national code

Ref country code: ES

Ref legal event code: FD2A

Effective date: 20030910