PTC thermistor device

Details PTC thermistor device PTC thermistor device

1999-03-22

2000-02-15

Gellner, Michael L.

Electrical resistors

Resistance value responsive to a condition

Current and/or voltage

338225D, 338 20, 338 21, H01C 710

Patent

active

060257717

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to a positive temperature coefficient (hereinafter referred to as PTC) thermistor device which includes a PTC element and more particularly, it relates to support structures for a PTC thermistor element.
2. Discussion of the Background
PTC thermistor devices are used with motor drive circuits or the like in electric refrigerators, for example. A PTC thermistor element which is employed in a PTC thermistor device is one of semiconductor temperature sensor devices, which noticeably increases its resistivity in a non-linear or exponential manner as the temperature increases and which has a positive temperature coefficient as a whole. Typically, such PTC thermistor element is held or housed in its associative vessel such as an enclosure or casing, and is attached to a motor drive circuit, for instance.
PTC thermistor elements are those devices having a function of suppressing flow of current by heat generation. However, where the PTC thermistor element is abnormal in operation, thermorunaway can arise due to flow of overcurrent, causing the element to rapidly increase in temperature, which would lead to element destruction.
Conventionally, even upon occurrence of the element destruction mentioned above, it is not possible to reliably interrupt or cut off the flow of overcurrent, which would result in an increase of the risk of combustion of the casing or the like due to continuous flow of such overcurrent. In view of this, it has been long desired that once the aforesaid element destruction occurs, any possible flow of overcurrent be successfully interrupted or shut down eliminating accidental firing or equivalents thereto, thus increasing reliability.
A conventional PTC thermistor device is shown in FIG. 15. In this figure, reference numeral 1 indicates a PTC thermistor element, 2 indicates electrodes of the PTC thermistor element 1, 3 indicates a support member of the PTC thermistor element 1, 5 indicates a casing, 6 and 7 indicate terminal sections, 8 and 9 indicate spring members as integral with the terminal sections 8 and 9 respectively, 10 indicates a spring contact piece (contact section to be contacted with electrode 2), and 11 indicates a spring contact piece support section.
The prior art illustrated in FIG. 15 is arranged such that the plate-shaped PTC thermistor element 1 having electrodes 2 formed on its both principal surfaces is housed within the insulating casing 5 and is elastically held by spring members 8 and 9 each consisting of an elastic or resilient metal plate, while causing the spring members 8 and 9 to be secured to the terminal sections 6 and 7. Each spring member 8 and 9 includes a spring contact piece support section 11 of a substantially constant width extending in parallel to the electrodes 2 on the principal surface of the PTC thermistor element 1, and spring contact pieces 10 (contact sections) which extend from respective ends of this spring contact piece support section 11 and being bent toward the principal surface electrodes 2 of PTC thermistor element 1 to become into contact with the electrodes 2 and thereafter being bent toward the spring contact piece support section 11 (see Unexamined Japanese Utility-Model Publication No. 3-99402).
Another PTC thermistor device belonging to the prior art is shown in FIG. 16. In this figure, numeral 15 indicates a PTC thermistor element, 16 indicates electrodes of the PTC thermistor element 15, and 17 and 18 indicate terminals. The prior art illustrated in FIG. 16 is arranged such that the PTC thermistor element 15 having electrodes 16 formed on two outer opposite surfaces thereof is elastically supported by a pair of terminals 17 and 18 with elasticity. In this case, the PTC thermistor element 15 is held between both terminals 17 and 18 (PTC thermistor element 15 is supported at three points) while the contact sections 19, 20 and 21 of the terminals 17 and 18 are asymmetrical on both surfaces of PTC thermistor element 15 (see Unexamined Japanese Util

REFERENCES:
patent: 4894637 (1990-01-01), Yamada et al.
patent: 5218336 (1993-06-01), Murakami
patent: 5606302 (1997-02-01), Ichida
patent: 5714924 (1998-02-01), Takeuchi et al.
patent: 5760336 (1998-06-01), Wang

Affiliated with

Also associated with

Rating

PTC thermistor device does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with PTC thermistor device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and PTC thermistor device will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1908951