JPH0822905A - Positive thermistor heater element - Google Patents

Abstract

PURPOSE:To fix a positive thermistor to a metallic heat radiator without using a bonding agent in high power and with the least uneven temperature of the air after passing through the positive characteristic thermistor heating element. CONSTITUTION:An electrode 12 is formed on both upper and lower surfaces of a planar positive characteristic thermistor 11, and it is held by a metallic heat radiator 15 fixing an aluminum radiating fins 14 to the inside of an aluminum made outer frame 13, while the outer periphery of the metallic heating radiator 15 is covered with a ring type heat resistant insulating material band 16 to be pressure-fixed to the inner side by a screw 17 to produce a positive characteristic thermistor heating element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PTC thermistor heating element used as a heating element such as a warm air heater.

[0002]

2. Description of the Related Art A PTC thermistor is a semiconductor ceramic whose resistance value rapidly increases at a certain temperature.
Therefore, when a voltage is applied to this, it generates heat at a constant temperature and is therefore widely used as a constant temperature heating element. A conventional PTC thermistor heating element will be described below with reference to the drawings.

FIG. 6 shows the structure of a conventional PTC thermistor heating element. In FIG. 6, reference numeral 1 is a positive temperature coefficient thermistor, and electrodes 2 formed by spraying aluminum are provided on the lower and upper surfaces thereof. Reference numeral 4 denotes a heat radiating fin formed by bending an aluminum thin plate in a wave shape. The metal radiating body 5 is obtained by sandwiching the heat radiating fin 4 between two aluminum thin plates 3a and 3b and joining them by brazing. Then, the PTC thermistor 1 and the metal radiator 5 are tightly fixed to each other via a conductive adhesive, and electrical conduction is achieved to obtain a PTC thermistor heating element.

[0004]

With the above-mentioned structure, in a warm air generator having a cylindrical blower port such as a dryer or a futon dryer in which a positive temperature coefficient thermistor heating element is used, the inside of the cylinder has a structure as shown in FIG. Since the rectangular parallelepiped positive temperature coefficient thermistor heating element is mounted, the area occupied by the positive temperature coefficient thermistor heating element with respect to the area of the circle is small and the amount of air passing through the positive temperature coefficient thermistor heating element is limited. Therefore, the electric power of the PTC thermistor heating element becomes small, and the temperature of the warmed air that has passed through the PTC thermistor heating element is different from the temperature of the unheated air around the outer periphery of the blower opening. However, there is a problem that the temperature unevenness occurs. Further, in order to bond the metal radiator 5 and the PTC thermistor 1 with an adhesive, a large-scale equipment and a large number of jigs are required, and there is a problem that the number of working steps increases.

The present invention makes it possible to increase the electric power by maximizing the space and increase the heat dissipation in the cylindrical space and to make the temperature of the air blown after passing through the PTC thermistor uniform. An object of the present invention is to provide a positive temperature coefficient thermistor heating element capable of significantly reducing the number of working steps by fixing a positive temperature coefficient thermistor and a metal heat radiator without using an adhesive.

[0006]

In order to achieve this object, the present invention provides a metal radiator by fixing metal radiator fins to the inside of a semicircular metal outer frame to obtain a positive characteristic. After sandwiching the upper and lower surfaces of the thermistor with two metal radiators,
A PTC thermistor heating element is obtained by covering the outer periphery with a band made of a ring-shaped insulating material having heat resistance, tightening it inside, and fixing it under pressure.

[0007]

With this configuration, it is possible to maximize the use of the cylindrical space, increase the heat dissipation of the PTC thermistor heating element, and increase the electric power. Further, since the positive temperature coefficient thermistor heating element can occupy the entire space, it is possible to minimize the unevenness of the blowing temperature after passing through the positive temperature coefficient thermistor heating element. Furthermore, since the positive temperature coefficient thermistor and the metal radiator can be fixed to each other without using an adhesive, the number of working steps can be significantly reduced by using simple equipment and jigs.

[0008]

【Example】

(First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing the structure of a PTC thermistor heating element according to the first embodiment of the present invention. FIG. 2 is a perspective view of a PTC thermistor used therein, in which electrodes 12 are formed on the upper and lower surfaces of the plate-shaped PTC thermistor 11 by aluminum spraying or the like. In FIG. 1, reference numeral 11 is a positive temperature coefficient thermistor, and upper and lower surfaces thereof are brazed with heat radiating fins 14 formed by corrugating an aluminum thin plate in a wavy shape on the inside of an outer frame 13 in which the aluminum thin plate is formed in a semicircular shape. It is sandwiched between metal heat radiators 15 obtained by being fixed by processing, the outer periphery of which is covered by a band 16 of an insulating material having heat resistance in the form of a ring, which is tightened inward by screws 17 and fixed by pressure.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is a perspective view showing the structure of a PTC thermistor heating element according to the second embodiment of the present invention. FIG.
In the figure, 11 is a positive temperature coefficient thermistor, and an outer frame 1 in which aluminum thin plates are formed in a semicircular shape on both upper and lower surfaces thereof.
3, a metal heat radiator 15 obtained by extrusion molding a structure of a heat radiation fin 14 in which a thin aluminum plate is formed in a grid shape is sandwiched, and the outer periphery thereof is covered with a band 16 of an insulating material having a ring-shaped heat resistance. The tip end of 16 is welded and fixed by welding while the metal radiator 15 is sufficiently tightened.

(Embodiment 3) A third embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 is a perspective view showing the structure of a PTC thermistor heating element according to the third embodiment of the present invention. Figure 5
Is an enlarged view of the joint between the band and the clasp before tightening the metal radiator. In FIG. 4, 11 is a positive temperature coefficient thermistor, 15 is a metal radiator, and the metal radiator 15 is a radiator fin 14 in which an aluminum thin plate is formed in a lattice shape inside an outer frame 13 in which the aluminum thin plate is formed in a semicircular shape.
The structure provided with is obtained by extrusion molding. The metal radiator 15 is sandwiched between the upper and lower surfaces of the positive temperature coefficient thermistor, the outer periphery of the metal radiator 15 is covered with a band 16 of a ring-shaped insulating material having heat resistance, and the tip of a clasp 18 attached to the tip of the band 16. The other end of the band 16 is hooked on the hook 19 of the part, and the stopper 18 is tilted around the fulcrum in the direction of tightening the metal radiator 15, and the hook 20 provided on the stopper 18 is provided at an appropriate position of the band 16. The fixed shaft 21 is press-fitted and fixed by pressing.

A positive temperature coefficient thermistor heating element according to Examples 1 to 3 and a conventional positive temperature coefficient thermistor heating element have a diameter of 60 mm.
The size was designed to be the maximum area that can be installed in the cylindrical wind tunnel of, and the power at 2.1 m / sec of air volume (Table 1) was used, and it was placed 5 cm away from the PTC thermistor heating element in the direction of the wind. The difference between the temperature at the outer periphery of the position and the temperature at the center of the cylinder is shown in (Table 2).

[0015]

[Table 1]

[0016]

[Table 2]

The positive temperature coefficient thermistor is 15 mm × 20.
The size of the conventional positive temperature coefficient thermistor according to the first, second, and third embodiments is 40 mm in length, 40 mm in height, and 15 mm in width. The diameter was 55 mm and the width was 15 mm. Also, 5 of each was used.

As is clear from Table 1, Examples 1 to 1
The PTC thermistor heating element according to No. 3 has a power of about 15% in the first embodiment as compared with the conventional PTC thermistor heating element.
In the third embodiment, the electric power is increased by about 17%, so that when the positive temperature coefficient thermistor heating element according to the first to third embodiments is used in the hot air generator having the cylindrical wind tunnel, the surface area of the metal radiator is increased. It can be seen that the power can be increased by increasing the size. Further, as is clear from (Table 2), the PTC thermistor heating elements according to Examples 1 to 3 were:
The difference between the temperature at the outer periphery of the positive temperature coefficient thermistor heating element and the temperature at the center of the cylinder at a position distant from the positive temperature coefficient thermistor heating element is smaller than that of the conventional positive temperature coefficient thermistor heating element.
It can be seen that the PTC thermistor heating elements according to 3 to 3 can reduce the unevenness of the blowing temperature after passing through the PTC thermistor heating element.

In Examples 2 and 3, the metal radiator 15 was obtained by extrusion molding the structure of the radiation fin in which the aluminum thin plate was formed in a lattice shape inside the outer frame in which the aluminum thin plate was formed in a semicircular shape. The metal radiator according to Example 1 may be used. Further, in Examples 1 to 3, the band 16
Is a heat-resistant insulating material, but a ring-shaped metal band having a heat-resistant insulating sheet inside may be used. Here, as the insulating material having heat resistance, an elastic polycarbonate resin, a phenol resin, or the like is preferable. The metal used for the PTC thermistor heating element is
Those having excellent thermal conductivity such as aluminum are preferable.

Further, the reason why the outer periphery is covered with the band 16 of the insulating material is that a short circuit does not occur when a voltage is applied to the upper surface of the PTC thermistor heating element.

The metal band covering the outer circumference is suitable for a band that is small in expansion and contraction due to heat. Further, in the ring-shaped metal band having a heat-resistant insulating sheet inside, it is preferable that the width of the inner insulating sheet is larger than the width of the metal band.

[0022]

As described above, according to the present invention, by arranging a metal radiator fin inside a metal outer frame forming a semicircular shape to form a metal radiator, the cylindrical space is maximized. It is possible to increase the power by increasing the heat dissipation of the PTC thermistor heating element. Further, since the positive temperature coefficient thermistor heating element can occupy the entire space, it is possible to minimize the unevenness of the blowing temperature after passing through the positive temperature coefficient thermistor heating element. Furthermore, since the positive temperature coefficient thermistor and the metal heat radiator can be fixed without using an adhesive, a positive temperature coefficient thermistor heating element can be realized in which the number of assembling steps can be significantly reduced.

[Brief description of drawings]

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

FIG. 2 is a perspective view of the same positive temperature coefficient thermistor.

FIG. 3 is a perspective view of a PTC thermistor heating element according to a second embodiment of the present invention.

FIG. 4 is a perspective view of a PTC thermistor heating element according to a third embodiment of the present invention.

FIG. 5 is an enlarged perspective view of the main part.

FIG. 6 is a perspective view of a conventional positive temperature coefficient thermistor heating element.

[Explanation of symbols]

 11 Positive Characteristic Thermistor 12 Electrode 13 Outer Frame 14 Radiating Fin 15 Metal Radiator 16 Band 17 Screw 18 Clasp 19 Hook 20 Hook 21 Fixed Shaft

Claims (2)

[Claims] 1. A metal radiating fin formed by electrically connecting a metal radiating fin inside a metal semicircular outer frame and the outer rim, and a plane portion of the two metal radiating bodies. , A positive temperature coefficient thermistor having electrodes on both upper and lower sides and a ring-shaped heat resistance provided on the outer circumference of the two metal radiators sandwiching the upper and lower sides of the positive temperature coefficient thermistor. A thermistor heating element having a band made of an insulating material having a. 2. The positive temperature coefficient thermistor heating element according to claim 1, wherein a metal band is provided on the outer periphery of the band made of an insulating material.