WO1999017321A1 - Dispositif de protection de circuits electriques comportant des parties electriques jointes par ultrasons au moyen d'un alliage de brasage - Google Patents

Dispositif de protection de circuits electriques comportant des parties electriques jointes par ultrasons au moyen d'un alliage de brasage Download PDF

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Publication number
WO1999017321A1
WO1999017321A1 PCT/US1998/019613 US9819613W WO9917321A1 WO 1999017321 A1 WO1999017321 A1 WO 1999017321A1 US 9819613 W US9819613 W US 9819613W WO 9917321 A1 WO9917321 A1 WO 9917321A1
Authority
WO
WIPO (PCT)
Prior art keywords
set forth
copper
silver
elemental
weight
Prior art date
Application number
PCT/US1998/019613
Other languages
English (en)
Inventor
Charles A. Newland
Original Assignee
Siemens Energy & Automation, Inc.
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
Priority claimed from US08/941,337 external-priority patent/US6049046A/en
Priority claimed from US08/941,334 external-priority patent/US6010059A/en
Application filed by Siemens Energy & Automation, Inc. filed Critical Siemens Energy & Automation, Inc.
Priority to EP98947169A priority Critical patent/EP1019930B1/fr
Priority to DE69814432T priority patent/DE69814432T2/de
Publication of WO1999017321A1 publication Critical patent/WO1999017321A1/fr

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/02—Contacts characterised by the material thereof
    • H01H1/021—Composite material
    • H01H1/023—Composite material having a noble metal as the basic material
    • H01H1/0231—Composite material having a noble metal as the basic material provided with a solder layer
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H11/00—Apparatus or processes specially adapted for the manufacture of electric switches
    • H01H11/04—Apparatus or processes specially adapted for the manufacture of electric switches of switch contacts
    • H01H11/041—Apparatus or processes specially adapted for the manufacture of electric switches of switch contacts by bonding of a contact marking face to a contact body portion
    • H01H11/042—Apparatus or processes specially adapted for the manufacture of electric switches of switch contacts by bonding of a contact marking face to a contact body portion by mechanical deformation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/58—Electric connections to or between contacts; Terminals
    • H01H1/5822—Flexible connections between movable contact and terminal

Definitions

  • This invention relates generally to the ultrasonic joining of electrically conductive materials. More specifically, it relates to the realization that by selecting certain brazing materials, ultrasonic welding can be used to join two diverse electrically conductive materials, which it is believed, have been previously considered incompatible for joining by ultrasonic welding to create a joint that can withstand electric current faults, such as occur in circuit breakers.
  • Electric circuit protection devices such as circuit breakers, for example, may be used to interrupt current flow relatively quickly to a circuit that is being protected by the protection device upon the occurrence of an overload, such as a fault. This has been referred to in the industry as tripping the breaker. Once the condition that gave rise to the trip has been corrected, the circuit breaker may be reset, such as by appropriately manipulating an operating handle in the case of a manually resettable circuit breaker.
  • circuit breaker When a circuit breaker trips because of a dead short fault, it is believed that relatively large magnitudes of electric current may flow through the interruptable current path of a circuit breaker, so as to initiate the trip. However, the circuit breaker integrity must be maintained until it finally completes the trip. Moreover, because it is resettable, a circuit breaker must be capable of maintaining its integrity over its specified life, during which the circuit breaker may be subjected to multiple instances of tripping and resetting.
  • the internal construction of a circuit breaker comprises various individual electric parts. Some of these parts are joined together by welding or brazing. A known method for joining certain parts comprises high temperature welding.
  • thermo welding wherein pressure is applied to the parts at a location where they are to be joined, and welding current is passed through the location to create temperatures sufficiently high to cause a certain degree of localized material melting and flow migration between the parts so that upon termination of the welding current, the molten mass solidifies to create the joint. It is believed that the thermal effects of resistance welding may act on the parts in a manner that undesirably affects one or more physical properties of at least one of the parts being joined.
  • One example of such a side effect comprises some annealing of all or a portion of a part.
  • Another known method for joining certain parts comprises ultrasonic welding wherein pressure is applied to the parts at a location where they are to be joined, such as by clamping them in a suitable fixture in an ultrasonic welder. Ultrasonic energy is then applied to that location to create a certain upsetting and flow of material between the parts which ceases upon termination of the application of the ultrasonic energy, thereby creating the joint. It is believed that one advantage of ultrasonic welding is the elimination or at least attenuation of annealing of the parts being joined. In any particular application, it is believed that the choice of using either resistance welding or ultrasonic welding depends on the composition of the parts being joined.
  • an electric contact is to be joined to another electric part, such as a terminal or a movable contact arm or blade
  • the contact comprises the combination of a refractory element, such as tungsten or molybdenum, and an electric conductor, such as silver or copper
  • the other part comprises, either predominantly or exclusively, a non-ferrous electric conductor, such as copper
  • the disposition of an attachment agent on a face of the contact that is to be placed in intimate surface-to-surface contact with the non-ferrous conductor is generally believed to be suitable for high-temperature welding.
  • the attachment agent should be compatible with the contact's conductor material; for example, being fine silver when the contact conductor comprises silver. It is believed, however, that such materials are inappropriate or at least not optimally suited for ultrasonic welding. It is also believed that refractory-based materials are at least generally not optimal candidates for the alloying that is necessary to create an acceptable joint by ultrasonic welding.
  • the present inventions relating to a novel method and a brazing material selection that provide for materials that previously have been believed to be inappropriate for satisfactorily joining parts by ultrasonic welding.
  • One aspect of the invention relates to a method of mechanically joining electrically conductive parts comprising, providing first and second electrically conductive parts that are to be joined to establish electric conductivity between them wherein a constituent of the first part comprises a non-alloying material and the second part comprises a predominance by weight of non-ferrous material, disposing brazing material between the parts at a location where they are to be joined, and joining the parts at that location by the application of ultrasonic energy, wherein the brazing material is selected to comprise at least two materials, one of the two materials being elemental copper, and the elemental copper being the largest single constituent of the brazing material by weight.
  • an electric circuit protection ⁇ device comprising an interruptable current path for interrupting current flow to a load including trip means for tripping the interruptable current path upon occurrence of a load fault, the interruptable current path comprising first and second electrically conductive parts that have been joined by ultrasonic welding to establish electric conductivity between them, the first part comprising non- alloying material, the second part comprising non-ferrous material, and a brazing material that has been acted upon by the ultrasonic welding to join the parts, the brazing material being selected to comprise at least two materials, one of the two materials being elemental copper, and the elemental copper being the largest single constituent of the brazing material.
  • Still another aspect of the invention relates to an electric conductor assembly comprising an electrically conductive contact and an electrically conductive contact carrier joined together by ultrasonic welding to establish electric conductivity between them, one of the contact and the carrier comprising non-alloying material, the other of the contact and the carrier comprising non- ferrous material, and a brazing material that has been acted upon by the ultrasonic welding to join the contact and the carrier, the brazing material being selected to comprise at least two materials, one of the two materials being elemental copper, and the elemental copper being the largest single constituent of the brazing material.
  • the elemental copper of the brazing material being at least 50% by weight of the brazing material, more particularly being an alloy consisting of substantially 80 parts elemental copper by weight, substantially 15 parts elemental silver by weight, and substantially 5 parts elemental phosphorus by weight;
  • the non-alloying material comprising a refractory material, more particularly the refractory material comprising at least 35% by weight of the contact, and more particularly being from the group consisting of silver tungsten, silver tungsten carbide, copper tungsten, copper tungsten carbide, and silver molybdenum;
  • the non-ferrous material being copper;
  • the brazing material comprising silver as another elemental material, the contact being infiltrated with silver.
  • Figure 1 is an elevation view, schematic in nature, illustrating a stage in the inventive method.
  • Figure 2 is an elevation view, schematic in nature, illustrating a further stage in the inventive method.
  • Figure 3 is an elevation view, schematic in nature, of parts that have been joined by the inventive method.
  • Figure 4 is an elevation view of a portion of a circuit breaker mechanism containing a contact arm assembly that includes a refractory-based contact joined to a two-piece contact arm in accordance with the present invention.
  • Figure- 5 is a view in the direction of arrows 5-5 in Figure 4.
  • Figure 6 is a view in the direction of arrows 6-6 in Figure 5 of one of the two contact arm pieces by itself.
  • Figure 7 is a view substantially in the direction of arrows 7-7 in Figure 4.
  • Figure 8 is a top view of Figure 4.
  • Figure 9 is an enlarged photomicrograph of a cutaway cross section through an actual joint between a contact and a contact arm created in accordance with the present invention.
  • Figure 10 is an enlarged photomicrograph of a cut- away cross section through another actual joint between another contact and another contact arm created in accordance with the present invention.
  • Figure 11 is an enlarged view, generally within the area 11 of Figure 10, that has been enhanced in brightness and contrast to show a particular feature.
  • FIGS. 1 to 3 show a contact, designated by the reference numeral 10, and a contact arm, designated by the reference numeral 12.
  • An exemplary contact 10 is a part having, for example, a silver-infiltrated refractory composition, silver-infiltrated tungsten or silver- infiltrated molybdenum.
  • An exemplary contact arm 12 is a part of substantially elemental copper.
  • a brazing alloy designated by the reference numeral 14 for use in joining the two parts 10, 12 comprises at least two materials, one of the two materials being elemental copper, with the elemental copper being the largest constituent of the brazing material.
  • a suitable brazing material is an alloy consisting of 80 parts elemental copper, 15 parts elemental silver, and 5 parts element phosphorus, all by weight.
  • brazing alloy it may be advantageous for the brazing alloy to be applied to a face of the silver-infiltrated refractory contact in an inert atmospheric oven (the oven not being shown in the drawing) .
  • parts 10 and 14 they are allowed to cool.
  • the face of contact 10 that contains the brazing alloy is then disposed in surface-to-surface contact with the copper contact arm 12 in an ultrasonic welder 16.
  • the parts are held clamped in the welder and suitable pressure and ultrasonic energy are applied to the clamped region to create a certain upsetting and cross-flow of materials between the intimately contacting surfaces.
  • the application of ultrasonic energy is then ended or terminated to stop the cross-flow.
  • the joined parts are finally removed from the welder to yield the finished assembly shown in Figure 3.
  • the joint that has been created is believed to be capable of withstanding relatively high electric current densities that occur in a circuit breaker upon occurrence of a circuit fault that causes the breaker to trip. Moreover, it is believed that the joint has been created with little or essentially no degradation in the physical properties, such as hardness, of the joined materials. Moreover, the beneficial use of a refractory based contact has been advantageously retained.
  • Ultrasonic welding machines for performing the joining that is the subject of the present invention are commercially available. They can be selected and set to meet specified performance criteria to accomplish part joining in accordance with relevant specifications, such as current carrying capacity, trip time, etc. Examples of suitable ultrasonic welders are: Sonobond Model No. MH-1545, available from Sonobond Ultrasonics Company, 200 East Rosedale Ave., Westchester, Pennsylvania 19380; and ATE Ultraweld 20 System available from American Technology Equipment, Inc., 25 Controls Drive, Shelton, Connecticut 06484.
  • FIGs 4 to 8 illustrate a portion of a circuit breaker mechanism including an actual contact 10 joined to a contact arm 12.
  • Contact arm 12 forms a carrier for the contact by an illustrative two-piece construction, comprising a first contact arm piece 12A and a second contact arm piece 12B.
  • Contact 10 is joined to the distal end of contact arm 12, creating a contact arm assembly 13.
  • the two pieces 12A, 12B are essentially mirror images of each other.
  • confronting portions of each piece 12A, 12B proximate the distal end of contact arm 12 comprises respective zones 16 where they are joined directly together. Such joining may be accomplished by ultrasonic welding or brazing.
  • each piece 12A, 12B has an abutment 18 whose free end is adapted to abut, but at the minimum at least closely confront, the free end of the opposite abutment 18.
  • each piece 12A, 12B has a lobe 20 that, in the completed circuit breaker, defines an axis 22 about which contact arm assembly 13 executes swinging motion.
  • Load terminal 24 is adapted to be mounted on a casing (not shown) of a circuit breaker, for example by a fastener, such as a headed screw, whose shank is passed a hole in the casing and threaded into an extruded hole 30 in the load terminal.
  • the end of terminal 24 designated 24A leads to a load circuit (not shown) .
  • the end designated 24B provides a cantilever mounting for bi-metal 28.
  • Bi-metal 28 comprises a nominally flat strip having a relatively higher expansion side 28A and a relatively lower expansion side 28B.
  • the distal end of bi-metal 28 and one end of braid 26 are joined together, such as by brazing.
  • the opposite end of braid 26 is joined, by brazing for example, to contact arm 12 distally proximal to a lobe 20 of one of the two pieces 12A, 12B, the one piece being 12A in the example depicted.
  • contact 10 When a finished circuit breaker containing the mechanism just described is in its "on" position, contact 10 has direct contact with another contact that is connected to a line terminal (not shown) . Hence a complete circuit exists from that line terminal and its associated contact, through contact 10, contact arm 12, braid 26, and bi-metal 28, to load terminal 24.
  • One type of fault condition that should cause the circuit breaker to trip is due to thermal energy input to bi-metal 28 sufficient to warp the bi-metal to an extent that causes operation of a trip mechanism (not shown) .
  • contact arm assembly 13 swings in the sense of arrow 29 in Figure 4 to separate contact 10 from the line terminal contact that it had been engaging. This breaks the continuity through the circuit breaker between the line terminal and load terminal 24, causing the circuit breaker to operate to "tripped" condition.
  • Figures 4 and 6 show adjoining flat rectangular surface areas 32 of contact arm pieces 12A and 12B.
  • Contact 10 has a rectangular surface area 34 of slightly larger overall area than the combined surface areas 32. Joining of surface area 34 to the surface areas 32 is advantageously accomplished by the present approach. The occurrence of a fault that should trip the circuit breaker may create relatively large current densities through the joint between contact 10 and contact arm 12. The present approach is believed to aid in better maintaining the integrity of the joint under such high stress conditions. This is important where small areas are involved.
  • interface areas less than about 1/4" X 5/16" are especially well- suited for successful joining, at least in the case of joining a contact to a contact arm in an electric circuit protection device like a circuit breaker.
  • "Interface area” is understood to include the area where the actual joining takes place. Specific examples of interface areas that have been used in practice of the inventive principles are 9/16" X 5/32" and 1/8" X 9/32".
  • the thickness of the contact may be any of a number of different thicknesses typically used for contacts. Examples of typical thicknesses may range up to about 3/16".
  • Figures 9 and 10 show two examples of actual joints created by use of the joining procedure.
  • the contact arm comprises predominantly copper, with small amounts of iron and silicon.
  • An example is Cu at least about 97- 99%, Si 1% or less, and Fe 2% or less.
  • the brazing alloy consists of substantially 80 parts elemental copper by weight, substantially 15 parts elemental silver by weight, and substantially 5 parts elemental phosphorus by weight.
  • the contact is 50% Ag and 50% WC by, weight.
  • the accompanying patent drawings of Figures 9 and 10 contain 50X photomicrographs. In each of Figures 9 and 10, it can be seen that brazing alloy 14 was joined to contact 10 before the ultrasonic welding of the contact to contact arm 12. Excess silver fills troughs of serrations in the contact.
  • brazing alloy appears as a layer overlapping the serrations, and the region of ultrasonic bonding is so labeled. It is believed that there is essentially complete bonding across the joint.
  • Figure 10 shows evidence of "swirling" at the interface, which is believed to indicate relatively good quality.
  • Figure 11 is believed to show the swirling in more detail.
  • the inventions are suitable for joining an electric conductor that is primarily copper to the following refractory-based materials: Silver-Tungsten; Silver Tungsten Carbide; Copper Tungsten; Copper Tungsten Carbide; and Silver Molybdenum.
  • silver-Tungsten Silver Tungsten Carbide
  • Copper Tungsten Copper Tungsten Carbide
  • Silver Molybdenum the relative percentages of the contact constituents may vary. Specific examples are given by the following table wherein hardness, density, and electrical conductivity data are representative. In the table, IACS refers to International Annealed Copper Standard.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Composite Materials (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Contacts (AREA)

Abstract

L'invention concerne un dispositif de protection de circuits électriques comportant un trajet du courant pouvant être interrompu destiné à interrompre le passage du courant à une charge, comprenant des éléments de déclenchement destinés à déclencher le trajet du courant pouvant être interrompu lors d'un défaut de charge. Le trajet du courant pouvant être interrompu comporte des première et seconde parties électriquement conductrices qui ont été jointes par soudage par ultrasons en vue d'établir entre elles une conductivité électrique, la première partie comprenant un matériau non allié, la seconde partie comprenant un matériau non ferreux et un matériau de brasage qui a été travaillé par soudage par ultrasons en vue de joindre les deux parties. Le matériau de brasage est sélectionné pour qu'il comporte au moins deux matériaux, l'un des deux matériaux étant du cuivre élémentaire, lequel cuivre élémentaire est le plus grand constituant du matériau de brasage.
PCT/US1998/019613 1997-09-30 1998-09-21 Dispositif de protection de circuits electriques comportant des parties electriques jointes par ultrasons au moyen d'un alliage de brasage WO1999017321A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP98947169A EP1019930B1 (fr) 1997-09-30 1998-09-21 Procede pour joindre par ultrasons des composants electroconductrices
DE69814432T DE69814432T2 (de) 1997-09-30 1998-09-21 Methode zum verbinden zweier elektrisch leitender teile mittels ultraschall

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US08/941,334 1997-09-30
US08/941,337 US6049046A (en) 1997-09-30 1997-09-30 Electric circuit protection device having electrical parts ultrasonically joined using a brazing alloy
US08/941,334 US6010059A (en) 1997-09-30 1997-09-30 Method for ultrasonic joining of electrical parts using a brazing alloy
US08/941,337 1997-09-30

Publications (1)

Publication Number Publication Date
WO1999017321A1 true WO1999017321A1 (fr) 1999-04-08

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PCT/US1998/019613 WO1999017321A1 (fr) 1997-09-30 1998-09-21 Dispositif de protection de circuits electriques comportant des parties electriques jointes par ultrasons au moyen d'un alliage de brasage

Country Status (4)

Country Link
EP (2) EP1261000B1 (fr)
DE (2) DE69819791T2 (fr)
ES (2) ES2211852T3 (fr)
WO (1) WO1999017321A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102012106053A1 (de) * 2012-07-05 2014-01-09 Doduco Gmbh Elektromechanischer Niederspannungsschalter

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4019876A (en) * 1975-04-19 1977-04-26 G. Rau Electrical contact element and method of producing the same
US4740770A (en) * 1985-10-31 1988-04-26 Merlin Gerin Operating mechanism for a low voltage electrical circuit breaker
WO1993011550A1 (fr) * 1991-12-04 1993-06-10 Siemens Aktiengesellschaft Contact avec un revetement de contact en argent et procede pour sa fabrication

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2694126A (en) * 1952-02-28 1954-11-09 Westinghouse Electric Corp Electrical contact member

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4019876A (en) * 1975-04-19 1977-04-26 G. Rau Electrical contact element and method of producing the same
US4740770A (en) * 1985-10-31 1988-04-26 Merlin Gerin Operating mechanism for a low voltage electrical circuit breaker
WO1993011550A1 (fr) * 1991-12-04 1993-06-10 Siemens Aktiengesellschaft Contact avec un revetement de contact en argent et procede pour sa fabrication

Also Published As

Publication number Publication date
DE69814432T2 (de) 2004-03-18
DE69814432D1 (de) 2003-06-12
EP1019930A1 (fr) 2000-07-19
EP1019930B1 (fr) 2003-05-07
DE69819791T2 (de) 2004-09-23
ES2199463T3 (es) 2004-02-16
EP1261000A1 (fr) 2002-11-27
EP1261000B1 (fr) 2003-11-12
ES2211852T3 (es) 2004-07-16
DE69819791D1 (de) 2003-12-18

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