EP0877403A1 - Schalter - Google Patents

Schalter Download PDF

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Publication number
EP0877403A1
EP0877403A1 EP96933639A EP96933639A EP0877403A1 EP 0877403 A1 EP0877403 A1 EP 0877403A1 EP 96933639 A EP96933639 A EP 96933639A EP 96933639 A EP96933639 A EP 96933639A EP 0877403 A1 EP0877403 A1 EP 0877403A1
Authority
EP
European Patent Office
Prior art keywords
contact
switch
terminal
sample
tin
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.)
Withdrawn
Application number
EP96933639A
Other languages
English (en)
French (fr)
Other versions
EP0877403A4 (de
Inventor
Wataru Maruzen Industry Co. Ltd. YAMAMOTO
Masatoshi Maruzen Industry Co. Ltd. KITAGAWA
Masahiko Sumitomo Metal Mining Co. Ltd. OTA
Tetsuya Omron Corporation MORI
Masato Omron Corporation DAIKOKU
Nobuaki Omron Corporation UENO
Shinichi Omron Corporation HASHIZUME
Takashi Omron Corporation NIWA
Shigenobu Omron Corporation KISHI
Koji Omron Corporation TAKAMI
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.)
Omron Corp
Original Assignee
Omron Corp
Omron Tateisi Electronics Co
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 Omron Corp, Omron Tateisi Electronics Co filed Critical Omron Corp
Publication of EP0877403A1 publication Critical patent/EP0877403A1/de
Publication of EP0877403A4 publication Critical patent/EP0877403A4/de
Withdrawn legal-status Critical Current

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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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/02—Contacts characterised by the material thereof

Definitions

  • the present invention relates to a switch such as a micro switch or a limit switch.
  • AgCdO based alloy has been widely used as a material for an electrical contact for power application used in this type of switch, in view of superior welding resistance and ablation resistance and inexpensiveness of the alloy.
  • AgCdO based alloy contains cadmium (Cd) which is a hazardous component. Accordingly, Ag-SnO based alloy not containing the hazardous component, such as Ag-Sn-In disclosed in United States Patent No. 4,243,413, for example, has been attracting attention as the material of the electrical contact.
  • AgCdO based alloy containing cadmium (Cd) which is hazardous to human tends to be restricted, while Ag-SnO based alloy is preferred as it does not contain any component hazardous to human body.
  • Ag-Sn-O based alloy is disadvantageous, however, since thin oxide (SnO 2 ) which is electrically insulative goes free and is deposited on a surface of the contact when an arc is generated as the contact is opened/closed, resulting in increased contact resistance value and hence abnormal heat built up. As a result, the contact is welded or ablated, and therefore it is inferior to AgCdO based alloy in welding resistance, ablation resistance and in cost.
  • the present invention was made in view of the above described problem and its object is to provide a switch having superior welding resistance and ablation resistance as well as high contact reliability.
  • the switch in accordance with the present invention for making contact and separation between a movable contact and a fixed contact in a snap action.
  • Each contact is formed of a material prepared by inner oxidation of an alloy having the composition of 2.0 to 5.0 wt% of tin, 5.0 to 8.0 wt% of indium, at most 0.5 wt% of iron family metal and remaining part of silver.
  • 2.0 to 5.0 wt% of tin, which improves welding resistance and 5.0 to 8.0 wt% of indium, which improves ablation resistance are mixed, whereby welding resistance and ablation resistance of the contact material itself can further be improved.
  • the aforementioned thin oxide (SnO 2 ) which is an insulating oxide goes free and is deposited on the surface of the contact as an arc is generated upon opening/closing of the contact, increasing contact resistance value.
  • the oxide which is deposited on the contact surfaces of the movable and fixed contacts is removed from the contact surfaces by rolling or wiping operation of the movable contact associated with the snap action.
  • the movable contact is brought into contact with the fixed contact at a high speed almost independent from the speed of operation of the switch by the snap action, and therefore the above described deposited oxide can be scattered and removed from the surfaces of the contact by the shock wave at the time of contact.
  • the contact surfaces of the movable and fixed contacts are always kept clean, so that the contact resistance value of the contacts is kept stable at a low value, whereby abnormal heat build up is prevented, and welding resistance and ablation resistance can be improved.
  • the movable contact is opened and separated at high speed from the fixed contact. Therefore, it is possible to further improve ablation resistance by quickly cutting arc generated at the time of separation, whereby a switch having high contact reliability is provided.
  • the switch is a micro switch.
  • the switch is a limit switch.
  • a micro switch or a limit switch having superior welding resistance and ablation resistance as well as high contact resistance can be provided.
  • the weight ratio of tin and indium is 1 tin to about 2 indium.
  • the weight ratio of tin and indium is about 3.2 tin to about 6.3 indium.
  • Fig. 1 is a cross section showing an example of the switch in accordance with the present invention applied to a micro switch.
  • Fig. 2 shows temperature increase characteristics of the switch shown in Fig. 1.
  • a common fixed terminal piece 2 a normally-open fixed terminal piece 3 and a normally-closed fixed terminal piece 4 are fixed, and a normally-open fixed contact 5 and a normally-closed fixed contact 6 are fixed opposing to each other at inner end portions of fixed terminal pieces 3 and 4.
  • a movable contact 7 which is brought into contact and separated from the normally-open and normally-closed fixed contacts 5 and 6 is fixed on a tip end portion 8a of movable contact piece 8, and a pressing body 9 is arranged at a base end portion 8b of movable contact piece 8.
  • Movable contact piece 8 includes a contact mechanism 10 for providing the snap action.
  • the contact mechanism 10 includes, for example, a compression spring 11 arranged between a bent portion at an inner end 2a of common fixed terminal piece 2 and the tip end portion 8a of movable contact piece 8, and a receiving member 12 having its tip end portion 12a rotatably engaged with an inner end portion 2b of common fixed terminal piece 2.
  • a base end portion 12b of the receiving member 12 held by engaging portion 13 is provided opposing to base end portion 8b of movable contact piece 8.
  • composition content ratio represents percentage by weight.
  • Sample A has, as alloy composition before internal oxidation, Sn: 5.1 wt%, In: 3.1 wt%, Ni: 0.2 wt% and remaining part of Ag.
  • Sample B contains Sn: 3.2 wt%, In: 6.3 wt%, Ni: 0.2 wt% and remaining part of Ag.
  • sample C contains Sn: 0.5 wt%, In: 9.5 wt% and remaining part of Ag.
  • opening/closing operation is repeated 50 times with power conduction to ramp load of AC125V-7.5A. Thereafter, opening/closing operation is repeated 25,000 times with power conduction to ramp load of AC125V-5.0A.
  • Samples A, B and C of Fig. 2 are switches in which normally-open fixed contact 5, normally-closed fixed contact 6 and movable contact 7 have the compositions and composition content ratios of samples A, B and C.
  • Table 2 shows measured temperatures (°C) of common fixed terminal piece (COM terminal) 2, normally-open fixed terminal piece (NO terminal) 3 and normally-closed fixed terminal piece (NC terminal) 4, respective contact resistance values (m ⁇ ) of normally-open fixed contact 5, normally-closed fixed contact 6 and movable contact 7, as well as test results of withstanding voltage, of three switches (Nos. 1 to 3) of respective samples A, B and C.
  • sample B has higher content of In as compared with sample A, and is superior in ablation resistance. Therefore, contact resistance values of respective contacts 5, 6 and 7 after test were low, and temperature increase of terminal pieces 2, 3 and 4 was small.
  • Sample C has still higher content of In as compared with sample B, and therefore the contacts are much ablated, contact resistance values of respective contacts 5, 6 and 7 after test were high and temperature increase of respective terminal pieces 2, 3 and 4 was large.
  • Table 3 shows results of similar temperature increase test performed on samples in which contact mechanism (Fig. 1) requiring the snap action is not provided at movable contact piece 8. The test was performed on known micro switches in which movable contact 7 is switched between fixed contacts 5 and 6 in a slow action.
  • Sample A Sample No. COM Terminal (°C) NO Terminal (°C) NC Terminal (°C) Contact Resistance Value (m ⁇ ) Withstanding Voltage No. 1 32 - 45 33 OK No. 2 30 47 - 250 OK No. 3 18 20 - 26 OK
  • Sample B Sample No. COM Terminal (°C) NO Terminal (°C) NC Terminal (°C) Contact Resistance Value (m ⁇ ) Withstanding Voltage No. 1 20 - 22 22 OK No. 2 24 24 - 20 OK No.
  • Fig. 2 shows temperature increase characteristic (dotted line) in slow action and temperature increase characteristic (solid line) in snap action of samples A, B and C, respectively. It is apparent from this figure also that in sample B, terminal pieces 2, 3 and 4 after test experience lower temperature increase as compared with samples A and C, and hence sample B has superior ablation resistance.
  • sample B containing much Sn has superior welding resistance, and hence ensures withstanding voltage (OK), while sample C containing less Sn has inferior welding resistance, and it cannot stand the applied voltage (NG).
  • tin oxide SnO 2
  • movable contact 7 removes the oxide deposited on the surfaces of the contact by rolling or wiping operation associated with the stop action. Further, the deposited oxide can be scattered and removed from the surfaces of the contacts by the shock wave caused at the time of contact by the snap action of movable contact 7 brought into contact with and separated from fixed contacts 5 and 6 at high speed almost independent from the speed of operation of the micro switch.
  • movable contact 7 is opened and separated at high speed from fixed contacts 5 and 6, and hence the arc generated at the time of contact and separation can be cut rapidly, further improving ablation resistance.
  • the switch in accordance with the present invention ensures improved welding resistance and ablation resistance as well as high reliability. Therefore, it exhibits superior effects when applied to a micro switch or a limit switch.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Composite Materials (AREA)
  • Materials Engineering (AREA)
  • Contacts (AREA)
EP96933639A 1995-10-12 1996-10-11 Schalter Withdrawn EP0877403A4 (de)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP291914/95 1995-10-12
JP7291914A JPH09106724A (ja) 1995-10-12 1995-10-12 開閉器
PCT/JP1996/002972 WO1997014164A1 (fr) 1995-10-12 1996-10-11 Commutateur

Publications (2)

Publication Number Publication Date
EP0877403A1 true EP0877403A1 (de) 1998-11-11
EP0877403A4 EP0877403A4 (de) 1999-08-04

Family

ID=17775098

Family Applications (1)

Application Number Title Priority Date Filing Date
EP96933639A Withdrawn EP0877403A4 (de) 1995-10-12 1996-10-11 Schalter

Country Status (5)

Country Link
EP (1) EP0877403A4 (de)
JP (1) JPH09106724A (de)
KR (1) KR19990064162A (de)
CN (1) CN1199497A (de)
WO (1) WO1997014164A1 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1584696A1 (de) * 2002-08-15 2005-10-12 Tokuriki Honten Company Limited HERSTELLUNGSVERFAHREN FÜR ELEKTRISCHES KONTAKTMATERIAL AUF Ag-OXIDBASIS UND DESSEN PRODUKT
US7189656B2 (en) 2001-06-01 2007-03-13 Tokuriki Honten Co. Ltd. Method for manufacturing ag-oxide-based electric contact material and product of the same

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3874941A (en) * 1973-03-22 1975-04-01 Chugai Electric Ind Co Ltd Silver-metal oxide contact materials
US4243413A (en) * 1979-02-26 1981-01-06 Chugai Denki Kogyo Kabushiki-Kaisha Integrated Ag-SnO alloy electrical contact materials

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5632376B2 (de) * 1974-10-08 1981-07-27
JPH07305128A (ja) * 1994-05-11 1995-11-21 Tanaka Kikinzoku Kogyo Kk Ａｇ−酸化物系電気接点材料

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3874941A (en) * 1973-03-22 1975-04-01 Chugai Electric Ind Co Ltd Silver-metal oxide contact materials
US4243413A (en) * 1979-02-26 1981-01-06 Chugai Denki Kogyo Kabushiki-Kaisha Integrated Ag-SnO alloy electrical contact materials

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO9714164A1 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7189656B2 (en) 2001-06-01 2007-03-13 Tokuriki Honten Co. Ltd. Method for manufacturing ag-oxide-based electric contact material and product of the same
EP1584696A1 (de) * 2002-08-15 2005-10-12 Tokuriki Honten Company Limited HERSTELLUNGSVERFAHREN FÜR ELEKTRISCHES KONTAKTMATERIAL AUF Ag-OXIDBASIS UND DESSEN PRODUKT
EP1584696A4 (de) * 2002-08-15 2005-10-12 Tokuriki Honten Company Ltd HERSTELLUNGSVERFAHREN FÜR ELEKTRISCHES KONTAKTMATERIAL AUF Ag-OXIDBASIS UND DESSEN PRODUKT

Also Published As

Publication number Publication date
KR19990064162A (ko) 1999-07-26
EP0877403A4 (de) 1999-08-04
WO1997014164A1 (fr) 1997-04-17
CN1199497A (zh) 1998-11-18
JPH09106724A (ja) 1997-04-22

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