JP2000182756A - Positive characteristic thermistor heating element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent influence of a thermal expansion difference and to provide great heat generation by aligning a plurality of elements having electrodes formed on the upper and lower main planes, arranging a plurality of heater units having metallic radiating elements adhering to both electrode surfaces via an adhesive and serving as an input terminal and a heat radiating plate at the same time, and electrically connecting the input terminals of the heater units together. SOLUTION: Four elements 1 principally consisting of barium titanate are arranged in the longitudinal direction. After a silicone adhesive is applied to the main plane of the element 1, a metallic heat radiating element 2 is overlaid while an input terminal 3 is arranged on the opposite side to the element 1, and then, the adhesive is heated and cured, and consequently, a heater unit is formed. These heater units are arranged in the longitudinal direction, and the adjacent input terminals 3 are caulked together by a connection terminal 4, and an electrically and mechanically jointed composite heating element is provided. In this way, the adhesive sufficiently absorbs thermal stress due to a thermal expansion difference between the metallic heat radiating element 2 and the element 1, so that a highly reliable composite heating element having an optical heat generation quantity can be provided easily.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive temperature coefficient thermistor heating element used for a constant temperature heating element or a hot air heater.

[0002]

2. Description of the Related Art Hereinafter, a conventional PTC thermistor heating element (hereinafter referred to as a heating element) will be described.

FIG. 2 is a diagram showing a configuration of a PTC thermistor heating element. In FIG. 2, 1 is a positive temperature coefficient thermistor element (hereinafter, referred to as an element), 2 is a metal radiator, and 3 is an input terminal.

First, an element 1 having electrodes formed on both upper and lower main planes
Are arranged in a straight line, and a silicon-based resin adhesive (not shown) is applied to the electrode surface of the element 1 so that the input terminal side of the metal radiator 2 made of aluminum is on the opposite side of the element 1. Then, the resin adhesive was heated and cured to form a heating element shown in FIG.

When a voltage is applied to the input terminal 3 of the heating element having the above-described structure, the metal radiator 2 serves as a conductive path, and a voltage is applied to the element 1. As a result, the element 1 generates heat and the heat is transferred to the metal radiator. Transfer to 2. If air is sent from one side of the heating element in this state, warm air can be obtained from the opposite side.

[0006]

In order to increase the amount of heat generated by the conventional heating element, the number of elements 1 constituting the heating element is linearly increased, or the heating elements are vertically stacked in a plurality of stages. Was. However, if the number of the elements 1 is increased in accordance with the required heat generation amount, the metal radiator 2 having a length corresponding to the number is required, and the types of the metal radiator 2 are increased, and the length of the metal radiator 2 is increased. As the length of the heat sink becomes longer, a large mechanical stress is applied to the adhesive due to the repetition of thermal expansion and contraction of the metal radiator 2 and the element 1, causing a problem that the bonding surface is peeled off.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide an electrically and mechanically highly reliable heating element which can obtain a large amount of heat without being affected by a difference in thermal expansion. And

[0008]

In order to solve this problem, the present invention provides a heater unit in which a metal radiator is bonded to both electrode surfaces of an element with an adhesive. By constructing a unit unit having a size that can absorb the expansion difference, and electrically connecting the unit heater unit in its longitudinal direction via a terminal plate provided for the input terminal as necessary, The purpose of the term can be achieved.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, a plurality of elements having electrodes formed on upper and lower main planes are linearly arranged, and both electrode surfaces serve as an input terminal and a heat sink. At least two or more heater units having a unit calorific value in which a metal radiator is bonded with an adhesive are arranged in the longitudinal direction, and input terminals of the heater units are electrically connected to each other by connection terminals. With this configuration, even if a plurality of heating elements are arranged in the longitudinal direction and electrically connected to each other, the adhesive can absorb mechanical stress due to a difference in thermal expansion between the radiator and the element, and an electrical element that generates a large amount of heat is generated. Thus, a heating element having high mechanical reliability can be obtained. However, the length of one heating element needs to be set to be shorter than the length in which the adhesive used can absorb the mechanical stress caused by the difference in thermal expansion between the radiator and the element.

Hereinafter, the heating element of the present invention will be described with reference to the drawings. (Embodiment 1) FIG. 1 shows a heating element according to an embodiment of the present invention. In FIG. 1, reference numeral 4 denotes a connection terminal. Since 1 to 3 have the same functions as those of the conventional product, the same numbers are given and the description is simplified.

First, an operation mainly comprising barium titanate is performed.
Element 1 with a starting temperature of 200 ° C and a length of 24 mm and a width of 15 mm
Four pieces are arranged in the length direction, and a silicone adhesive is applied to the main plane.
After application, set the input terminal 3 on the opposite side of the
Heat body 2 is piled up, about 16kg / cm ^Two1 while pressurizing with pressure
Heat and cure the adhesive at a temperature of 20 ° C, 400W units
A heater unit was manufactured. Note that the number of firings per element
The calorific value used was 100 W.

Next, as shown in FIG. 1, three unit heater units are arranged in the longitudinal direction, and the adjacent input terminals 3 are caulked with the connection terminals 4 to be electrically and mechanically joined.
A composite heating element of 00W was completed. In this configuration, when a voltage is applied to the input terminal 3 of the composite heating element, the radiator of each unit heater unit generates heat. When air is sent from one side to this, warm air is obtained from the opposite side.

Conventionally, a heater unit in which 100 W elements 1 having a length of 24 mm and a width of 15 mm are arranged in a straight line has a limit of 600 W in order to suppress peeling due to mechanical stress of the adhesive, and a heat generation exceeding this limit. In order to obtain the amount, it was necessary to stack the unit units in the vertical direction. However, in the present invention, the adhesive can sufficiently absorb the mechanical stress due to the difference in thermal expansion between the metal radiator 2 and the element 1. By connecting the unit heater unit of 400 W in the longitudinal direction, it is possible to easily produce an electrically and thermally reliable composite heating element having a desired heating value.
Also, since there is one input terminal 3, the wiring is simple.

[0014]

As described above, according to the present invention, there is provided a unit heater unit in which the adhesive for bonding the radiator and the element is set to a length capable of sufficiently absorbing the mechanical stress caused by the difference in thermal expansion between the radiator and the element. By connecting a plurality of heating elements in the longitudinal direction, it is possible to easily form a highly reliable composite heating element having an arbitrary amount of heat generation with a small number of input terminals.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a PTC thermistor heating element according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a conventional PTC thermistor heating element.

[Explanation of symbols]

 1 element 2 metal radiator

Claims (1)

[Claims] 1. A unit heat generating device in which a plurality of PTC thermistor elements having electrodes formed on upper and lower main planes are linearly arranged, and a metal heat radiator serving also as an input terminal and a heat radiating plate is bonded to both electrode surfaces with an adhesive. A positive temperature coefficient thermistor heating element characterized in that at least two or more heater units each having an amount are arranged in a longitudinal direction, and input terminals of said heater units are electrically connected to each other by connection terminals.