Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H1/00—Contacts
  • H01H1/50—Means for increasing contact pressure, preventing vibration of contacts, holding contacts together after engagement, or biasing contacts to the open position
• • 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
• • 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
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H1/00—Contacts
  • H01H1/12—Contacts characterised by the manner in which co-operating contacts engage
  • H01H1/14—Contacts characterised by the manner in which co-operating contacts engage by abutting
  • H01H1/20—Bridging contacts
• • 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
  • H01H11/045—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 with the help of an intermediate 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
  • H01H2011/046—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 plating
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H3/00—Mechanisms for operating contacts
  • H01H3/60—Mechanical arrangements for preventing or damping vibration or shock

Definitions

• the invention relates to a low-voltage electromechanical switch according to the preamble of claim 1 with a movable switching member having an electrically conductive support and at least one attached to this support electrical contact piece.
• the movable contact piece meets when closing the switch on a fixed contact. This can lead to a bouncing of the two contacts. Bouncing is a mechanically induced disruptive effect. For a short time, in the millisecond range, there is a multiple closing and opening of the switch. Rarely can the bouncing also occur when opening the switch. The reason for the bouncing are suspensions on components of the switch mechanism. If the switch briefly opens again due to the bounce, then an arc burns above the arc voltage between the fixed contact and the movable contact piece of the switch.
• the contact surface At the base of the arc there is a local melting of the contact surface and possibly a spattering of the contact material, whereby the contact loses ground. This loss of contact material is also referred to as burnup. Burning shortens the life of the switch. In addition, the sprayed contact material may deposit on other surfaces of the switch and cause interference.
• the present invention has for its object to reduce the burn caused by switching operations of the contacts of the electromechanical switch.
• the low-voltage electromechanical switch according to the invention has a movable switching element which has an electrically conductive carrier and at least one electrical contact piece attached to this carrier.
• the support is at least partially made of a metal or of an alloy having a density of less than 5 g / cm 3 .
• a carrier according to the invention having the same dimensions as in the prior art has a lower mass than a carrier made of copper. This reduces the tendency to bounce or is completely prevented. As a result, the frequency of occurrence of electric arcs considerably decreases. The occurrence of fewer arcs leads to a longer life of the low-voltage switch.
• the carrier is made of a light metal or a light metal alloy.
• light metals in particular aluminum, magnesium and lithium and their alloys in question.
• the light metals may be alloyed with other metals having a density of 5 g / cm 3 or more.
• Particularly preferred are alloys of aluminum, magnesium and lithium with each other. They are characterized by a particularly low density and good electrical conductivity.
• the carrier is provided, at least in a subregion of the carrier adjacent to the at least one contact piece, with a layer of a material with good electrical conductivity, which does not ignite in the air under arc action. This avoids the risk that the light metal will ignite under the action of the arc, if its foot should move down from the contact piece mounted on the carrier.
• the layer which does not ignite under arc effect, are particularly well conductive metals such as copper, silver, iron and alloys of these metals.
• this layer is at least 0, 1 mm thick. Thinner layers increase the risk that the arc penetrates the layer and ignites the light metal underneath. Conveniently, the layer is not thicker than 1 mm; a larger thickness does not lead to a significant improvement in the resistance to arcing. Preferably, the thickness of the layer is 0.4 mm to 0.6 mm.
• the support consists essentially of velvet of a light metal or a light metal alloy. This allows a particularly low mass of the carrier and thus a particularly low or vanishing inclination of the low-voltage switch for bouncing or makes it easier to prevent the bouncing. Compared to a conventional copper support, its mass can thus sink to less than half, e.g. B. to 1/3 or 1/4 of the mass of a conventional copper carrier with the same dimensions.
• the layer of the material which does not ignite under arc effect, to exert their effect, it must in any case be provided on that side of the carrier on which the contact piece or - if two contact pieces are provided - both contacts are attached. On the other side of the carrier such a layer must not be provided. Preferably, however, such a layer is also provided on that side of the carrier which faces away from the one contact piece or the plurality of contact pieces of the carrier. This has the advantage that when the temperature of the carrier changes, different thermal expansion coefficients of the carrier material and the material of the layer provided on the carrier do not lead to a curvature of the carrier.
• the layer of the material which does not ignite under arc action is provided on the entire surface of the side of the support on which the at least one contact piece is mounted, and preferably also on the entire surface of the side of the support which is the at least one Contact piece facing away. Then, in all circumstances, it is ensured that the base of an arc, should it descend from one of the contacts, can in any case only move on the layer which consists of the material which does not ignite under arc action.
• the electrically conductive support of the at least one contact piece often consists of a metal sheet and may be a stamped part or a stamped and bent part. If only the side of the carrier on which the at least one contact piece is located, hereinafter referred to as the front side of the carrier, is a layer of the material which does not ignite under the action of arcing, and even if there is such a layer on the rear side of the carrier, which faces away from the at least one contact piece, but the carrier does not have a layer on all its surfaces which does not ignite upon arc action, then corrosion, especially contact corrosion. To counter this, one could think of coating the carrier on all sides with the material which does not ignite under arc effect.
• the coating of the support on all sides can be effected by means of a wet-chemical coating process, namely in an electrolytic bath or in a bath which operates without external electrolysis with a chemical reduction. In this way it would be possible to coat the support on all sides with a material which does not ignite under the action of an arc, with a galvanic coating being preferred. However, it would be too costly, the few tenths of a millimeter thick layer, which is to protect the support for the at least one electrical contact piece from arcing, altogether from a galvanic bath or from a chemically-reductive bath.
• a material which does not ignite under the action of an arc is deposited by wet-chemical means, in particular galvanically.
• such a protective layer is applied on all sides on the carrier, possibly also on the already plated by roll-plating layer of the material, which does not ignite under arcing. Only then is the at least one contact piece fixed by a conventional method on the carrier, for. B. by welding, brazing or riveting.
• the invention is suitable for all types and forms of carriers that are common in low-voltage switches.
• the carrier may form a contact bridge, be a contact spring or attached to the tip of a spring.
• the present invention is not only a low-voltage switch according to claim 1, but also a switching element for a low-voltage switch, which makes the low-voltage switch to a low-voltage switch according to the invention when used as intended.
• Figure 1 shows a longitudinal section through the rear derailleur of an inventive
• Low-voltage switch which is designed as a bridge switch
• FIG 2 shows the view II on one end of the contact bridge of the switch shown in Figure 1.
• the low-voltage switch has two fixed contacts 1 and 2, which z. B. are fixed by brazing on two busbars 3 and 4, which in turn are mounted on an insulating support plate 7. Between the two fixed contacts 1 and 2 and the busbars 3 and 4 is in each case a brazing layer 5 and 6 respectively.
• the two fixed contacts 1 and 2 are two movable contact pieces 8 and 9 opposite, which are attached to a switching element formed as a contact link 10, which can be moved by an actuator, symbolically represented by two arrows 1 1, back and forth to either the contact pieces 8 and 9 with the opposite fixed contacts 1 and 2 to bring into contact, whereby between the two busbars 3 and 4, a conductive connection is created, or to lift the contacts 8 and 9 of the fixed contacts 1 and 2 and thereby the conductive connection between the two busbars 3 and 4 to separate.
• the actuator it may, for. B. is an electromagnet with a displaceable rod-shaped iron core, which is coupled to the contact bridge 10, wherein between the iron core and the contact bridge 10, a spring may be provided.
• the contact bridge 10 has an electrically conductive carrier 12 made of a light metal or a light metal alloy, for. B. of an aluminum-magnesium alloy.
• the carrier 12 is on its front side 12a and on its back 12b by a method of roll cladding over the entire surface with a layer 1 3 plated from a highly electrically conductive material, which is not ignited under arcing, in particular copper.
• the thickness of the two layers 13 is a few tenths of a millimeter.
• the clad carrier 12 is additionally provided on all sides galvanically with a protective layer 14 which consists of the same material as the layers 1 3 and preferably has a thickness of about 5 ⁇ .
• the galvanically applied protective layer 14 is preferably made of copper.
• the two movable contact pieces 8 and 9 are fixed, for. B. by brazing.
• the brazing layers 15 and 16 are shown schematically.
• the protective layer 14 has been applied after the roll-cladding of the two layers 13 and also extends over the layers 13.

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

Applications Claiming Priority (2)

Publications (1)

Family

ID=48746469

Family Applications (1)

Country Status (6)

Families Citing this family (2)

Family Cites Families (11)

• 2012
  • 2012-07-05 DE DE201210106053 patent/DE102012106053A1/de not_active Withdrawn
• 2013
  • 2013-06-26 BR BR112014033106A patent/BR112014033106A2/pt not_active IP Right Cessation
  • 2013-06-26 CN CN201380042962.7A patent/CN104541351A/zh active Pending
  • 2013-06-26 WO PCT/EP2013/063427 patent/WO2014005908A1/de active Application Filing
  • 2013-06-26 EP EP13734010.5A patent/EP2870617A1/de not_active Withdrawn
• 2015
  • 2015-01-02 US US14/588,551 patent/US20150114809A1/en not_active Abandoned

Non-Patent Citations (1)

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