JPH0393202A - Positive temperature coefficient thermistor device - Google Patents

Abstract

PURPOSE:To eliminate deviation of thermal expansion and watt loss of an element, to improve reliability and to realize simple assembly by forming a recessed part whereto a spring contact fits on both edge sides of a positive temperature coefficient thermister. CONSTITUTION:Two connecting terminals 11, 12 are set to specified positions of one container 3b so that both spring contacts 16, 17 are opposed. A positive temperature coefficient thermister element 4 is thrusted between the springs 16, 17 from above. An insertion position of the element 4 is determined by fitting of ends of the springs 16, 17 into a recessed part 14 of the element 4, and at this position, the springs 16, 17 come into contact with an approximately middle of both edge sides of the element 4. Thereby, it is possible to set the element 3 securely to a specified position only by inserting the element 4 into the springs 16, 17 as far as a position wherein ends of the springs 16, 17 are fit to the recessed part 14 when the element 4 is incorporated in a case 3a. As a result, it is possible to reduce a temperature difference produced in middle and peripheral parts of the element 4 and to reduce deviation of heat expansion of the element 4, thereby preventing breakdown of the element.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a positive temperature coefficient thermistor device used in a starting relay for an electric motor and the like.

(Example) Conventional technology Conventionally, this type of positive temperature coefficient thermistor device was
As disclosed in Japanese Patent No. 9669, etc., a case made of an insulating material, a disc-shaped positive temperature coefficient thermistor element housed in the case, electrodes attached to both end faces of the element, A positioning insulating plate having a hole in the center for accommodating the element and inserted into a groove in the inner wall of the case, and a spring that is in EE contact with each electrode on both end surfaces of the element and supporting the element within the case. This positive temperature coefficient thermistor device is connected to the starting circuit of the motor. here,
Positive temperature coefficient thermistor elements are generally formed by adding a small amount of a semiconductor agent to titanium sambarium (BaTi04) to make it a semiconductor, and take advantage of the property that the resistance value increases rapidly at temperatures above the Curie point. has been done. In addition, the electrodes on both end faces of the device are attached by baking silver paste onto the electroless nickel film. (c) Problems to be Solved by the Invention However, according to the above structure, since an insulating plate is used for positioning the positive temperature coefficient thermistor element when setting it, the element is There is a problem in that heat easily escapes through the insulating plate, and the temperature difference between the center and periphery of the element becomes large, causing uneven thermal expansion of the element, causing destruction of the element, and resulting in a lack of reliability. Ta. In addition, there was a problem in that the high heat (100-odd degrees Celsius) of the element was easily transmitted to the case through the insulating plate, increasing the leakage current of the element and increasing the watt loss. The present invention was developed in view of these points, and it eliminates uneven thermal expansion and watt loss of the element, improves reliability and reduces power consumption, and provides good assembly workability and stable characteristics. The purpose is to provide a positive temperature coefficient thermistor device. (2) Means for Solving the Problems The PTC thermistor device of the present invention includes a case made of an insulating material, a disk-shaped PTC thermistor element housed in the case, and a PTC thermistor element covered with both end faces of the element. The attached electrode,
and a spring contact that presses against each electrode on both end surfaces of the element and supports the element within the case, wherein recesses into which the spring contacts fit are formed on both end surfaces of the positive temperature coefficient thermistor. This is what I did. (Umbrella) Effect The positive temperature coefficient thermistor device of the present invention has the above-described configuration, so that when the positive temperature coefficient thermistor element is assembled into the case, the spring contact is extended until the tip of the spring contact fits into the recess of the element. By simply inserting the element in between, the element can be reliably set in the specified position. This makes it possible to eliminate the insulating plate in the conventional configuration, prevent the temperature difference between the center and peripheral parts of the element from increasing, eliminate uneven thermal expansion of the element, and prevent element destruction. By almost eliminating heat conduction from the element to the case, leakage current of the element is reduced, watt loss is kept small, and power consumption can be reduced.

(f) Examples Examples of the present invention will be described below based on the drawings. Reference numeral 1 denotes an airtight container housing the electric compressor main body (not shown), and a hermetic terminal 2 is provided in this container.
3 is a positive temperature coefficient thermistor device that is inserted into the two pins of the hermetic terminal 2 and has a built-in positive temperature coefficient thermistor element 4. 5 is a protection device which is also inserted into the remaining one of the hermetic terminals 2 and has a built-in overload relay 6. 7 is a single-phase induction motor for driving the electric compressor main body,
This motor is constructed by connecting a main winding 9 and an auxiliary winding 10 in parallel to a single-phase power supply 8. The positive temperature coefficient thermistor element 4 is connected in series to the auxiliary winding 10, and the overload relay 6 is connected to a common line between the main winding 119 and the auxiliary winding 10. The positive temperature coefficient thermistor device 3 includes a case 3c formed by connecting two bodies 3a and 3b made of an insulating material (polybutylene terephthalate) at their respective openings, and a disk-shaped positive coefficient thermistor housed in the case. It consists of a thermistor element 4 and two coupling terminals 11 and 12 arranged on both sides of the thermistor element to support the positive temperature coefficient thermistor element. The coupling terminal 11
．． 12 is in pressure contact with both side end surfaces of the element 4 to attach the element to the case 3.
Spring contact 16.17 clamped in C and receptacle terminal 18.1 inserted into the pin of hermetic terminal 2
It is formed by spot welding 9 and 9. Moreover, electrodes 13 formed by baking silver paste on an electroless nickel film are adhered to both end surfaces of the thermistor element 4. Furthermore, four recesses 14 are formed on both end faces of the element 4, as shown in FIGS. 5 and 6. This positive temperature coefficient thermistor device is assembled in the following order. First, two coupling terminals 1 are placed so that both spring contacts 16 and 17 face each other at a predetermined position on one container body 3b.
1. Set 12. Next, both spring contacts 16.17
In between, screw in the positive temperature coefficient thermistor element 4 from above. Here, the insertion position of the element 4 is determined by fitting the tips of the spring contacts 16.17 into the recesses 14 of the element. It will be pressed against the center. Finally, the other vessel body 3a is placed over the opening of the vessel body 3b and joined to complete the process. In the PTC thermistor device constructed in this way, when the PTC thermistor element 4 is assembled into the case 3c, the spring contacts 16 and 17 are pushed up to a position where the tips of the spring contacts 16 and 17 fit into the recesses 14 of the element. By simply inserting the element 4 between the contacts 16 and 17, the element can be reliably set in a predetermined position. As a result, stable characteristics can be obtained even if the insulating plate for positioning used in the conventional configuration is eliminated.
As a result, it is possible to reduce the temperature difference occurring between the center and the periphery of the element 4, reduce uneven thermal expansion of the element 4, and prevent destruction of the element. Furthermore, heat conduction from the element 4 to the case 3c can be almost eliminated, and the leakage current of the element 4 is reduced, so that watt loss can be kept small and power consumption can be reduced. Furthermore, in this embodiment, electrodes 13 are provided on all end surfaces of the element 4.
The case where the element 4 and the spring contactor 16 are attached is explained above.
, 17 only at the recess 14, the electrode 13 only needs to be attached to the recess 14, and in this case, the expensive material of the electrode 13 can be saved. Furthermore, recess 14
The number and shape of are not limited to this, for example,
It is also possible to form a large circular recess in which all the contacts are caught. (G) Effects of the Invention As described above, according to the present invention, it is possible to eliminate unbalanced thermal expansion of elements and watt loss, improve reliability and reduce power consumption, and improve assembly workability. We can provide a positive temperature coefficient thermistor device that provides stable characteristics.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a PTC thermistor device and a protection device showing an embodiment of the present invention, Fig. 2 is an electric circuit diagram of a single-phase induction motor of a split-phase start type, and Fig. 3 is an illustration of a PTC thermistor device. 4 is a cross-sectional view of the PTC thermistor device, FIG. 5 is an enlarged view of the main part of FIG. 4, and FIG. 6 is a plan view of the PTC thermistor element. 3@, 3b... vessel body, 3C... case, 4...
・Positive characteristic thermistor element, l3... electrode, 1
4... recess, 16.17... spring contactor.

Claims (1)

[Claims] (1) A case made of an insulating material, a disc-shaped positive temperature coefficient thermistor element housed in the case, electrodes attached to both end faces of the element, and each electrode on both end faces of the element. and a spring contactor that presses into contact with the element and supports the element within the case, wherein both end faces of the positive temperature coefficient thermistor are provided with:
A positive temperature coefficient thermistor device characterized by forming a recess into which a spring contactor is fitted.