JPH0621191U - heater - Google Patents

Abstract

(57) [Summary] [Structure] Cylindrical PTC consisting of positive temperature coefficient thermistor
The heating element 1, the electrodes 2.2 provided on the upper and lower surfaces of the PTC heating element 1, a pair of flat metal terminals 3.3 electrically connected to the upper and lower electrodes 2.2, and the upper side It has a fixing hole penetrating from the metal terminal 3 to the lower metal terminal 3 through the PTC heating element 1 and an electric insulating film 4 covering the whole of the metal terminal 3 except for the feeding portions 3a. heater. [Effect] Since the heater can be screwed to the object to be heated by passing the screw through the fixing hole, heat can be efficiently transferred to the object to be heated. Further, since the coating is performed with the electric insulating film 4, the heater can be electrically insulated from the object to be heated. Thereby, even if the object to be heated is a metal, it can be efficiently heated.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a heater using a PTC material (positive temperature characteristic thermistor) as a heating element.

[0002]

[Prior art]

 A heater using a PTC material as a heating element has extremely high safety because the temperature of the heater is self-controlled by the PTC characteristics, and an accident such as abnormal heat generation is unlikely to occur. Moreover, since it has a simple structure in which lead wires are soldered to the upper and lower surfaces of the disk-shaped PTC heating element, it is excellent in mass productivity.

[0003]

[Problems to be solved by the device]

 However, in the above-described conventional configuration, it is difficult to bring the heater into close contact with the object to be heated because a protrusion is formed at the connecting portion between the PTC heating element and the lead wire. Therefore, there is a problem that the object to be heated cannot be efficiently heated.

When the object to be heated has conductivity, it is necessary to electrically isolate the PTC heating element from the object to be heated. For this reason, measures such as housing the PTC heating element in an insulating case made of alumina, for example, have been taken. However, since a new insulating case is required, there is a problem that component cost and manufacturing cost increase. Have

[0005]

[Means for Solving the Problems]

 In order to solve the above problems, the heater of the present invention has a flat plate-shaped heating element made of a positive temperature coefficient thermistor, electrodes provided on the upper and lower surfaces of the heating element, and an upper electrode and a lower electrode, respectively. It has a pair of connected flat metal terminals, a fixing hole that penetrates from the upper metal terminal to the lower metal terminal via the heating element, and an electrical insulating film that covers the entire metal terminal except the power supply part. It is characterized by doing.

[0006]

[Action]

 With the above configuration, a flat plate-shaped heating element made of a positive temperature coefficient thermistor, electrodes provided on the upper and lower surfaces of the heating element, and a pair of flat plate-shaped metal terminals electrically connected to the upper and lower electrodes, respectively. , It has a fixing hole that penetrates from the upper metal terminal to the lower metal terminal through the heating element, and an electrical insulating film that covers the entire metal terminal except the power supply part of the metal terminal. , The heater can be screwed to the object to be heated. As a result, the upper surface (or the lower surface) of the heater can be brought into close contact with the object to be heated, so that the heat generated by the heating element can be efficiently transferred to the object to be heated. Moreover, since the flat metal terminal is used, the contact area between the heater and the object to be heated can be increased. This further improves the heat transfer efficiency. Further, since the heater is coated with the electrically insulating film, the heating element can be electrically insulated from the object to be heated. Thereby, even if the object to be heated is a conductor, it can be efficiently heated.

[0007]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

As shown in the vertical sectional view of FIG. 1 and the perspective view of FIG. 2, the heater of this embodiment has a cylindrical PTC heating element 1 and electrodes 2 formed on the upper and lower surfaces of the PTC heating element 1. 2 and the metal terminals 3 and 3 provided on the electrodes 2 and 2 and having holes substantially equal to the inner diameter of the PTC heating element 1 and the power supply portions 3a and 3a of the metal terminals 3 and 3. It is composed of an electric insulating film 4 formed as described above.

The structure of the above heater will be described in more detail based on the manufacturing process of FIG.

First, as shown in FIG. 1A, the cylindrical PTC heating element 1 is fired. As a material for the PTC heating element 1, for example, a ceramic semiconductor containing BaTiO ₃ as a main component is used. By substituting a part of Ba with Sr or Pb, the self-control temperature (Curie temperature) can be set to any temperature between normal temperature and 300 ° C.

Next, as shown in FIG. 1B, for example, silver paint is applied to the upper and lower surfaces of the PTC heating element 1 and baked. As a result, the electrodes 2.2 are formed.

Then, as shown in FIG. 1C, a flat plate-shaped metal terminal 3 having a hole substantially equal to the inner diameter of the PTC heating element 1 is used, for example, an epoxy / silver mixed adhesive made by Degussa. Stick it on the electrodes 2 and 2. Then, this is heated to connect the metal terminal 3 to the electrode 2.

The semi-finished product (FIG. 2 (d)) obtained in this manner is used as a liquid flame-retardant silicone resin (for example, KE1212 manufactured by Shin-Etsu Chemical Co., Ltd.) except for the power supply part 3a at the tip of the metal terminal 3. Dip. As a result, the electric insulating film 4 is formed except for the power feeding portion 3a of the metal terminal 3, and the heater of FIG. 2 is obtained.

In the above configuration, the PTC heating element 1 generates heat by supplying power to the power feeding portions 3a, 3a of the metal terminals 3, 3. When the temperature of the heater rises near the Curie temperature of the PTC heating element 1, the electric resistance of the PTC heating element 1 rapidly increases. Therefore, the amount of heat generated is reduced, and the temperature of the heater is lowered. When the temperature decreases, the electric resistance of the PTC heating element 1 decreases again and the amount of heat generation increases. In this way, since the heat generation temperature is self-controlled, the heater temperature can be kept constant.

In this embodiment, since a hole (fixing hole) is provided in the center of the heater, a screw can be threaded through the hole to fix the heater to the object to be heated. As a result, the upper surface (or the lower surface) of the heater can be brought into close contact with the object to be heated, so that the heat generated by the PTC heating element 1 can be efficiently transferred to the object to be heated. Moreover, since the flat metal terminal 3 is used, the contact area between the heater and the object to be heated can be increased. This further improves the heat transfer efficiency.

Since the heater is coated with the electric insulating film 4, the PTC heating element 1 can be electrically insulated from the object to be heated. As a result, even if the object to be heated is a metal, it can be efficiently heated.

Further, if a silicon resin is used as the electric insulating film 4, waterproof property can be imparted, and therefore the heater of this embodiment can be used for heating / keeping heat of liquid such as water or milk. Further, if silicon resin is used as the electric insulating film 4, flame retardancy can be imparted.

As the electric insulating film 4, any material other than silicon resin can be used as long as it has a high electric insulating property and a small heat shrinkage. For example, urethane resin or the like for electrical insulation may be used.

In the above examples, the cylindrical PTC heating element 1 was used. However, in order to increase the thermal contact with the object to be heated, it is flat and has holes for screwing. , PTC heating element 1 may have any shape.

Further, a screw thread may be provided in the hole for screwing.

[0021]

[Effect of device]

 As described above, the heater of the present invention is provided with a flat plate-shaped heating element made of a positive temperature coefficient thermistor and a pair of heating elements provided on the upper and lower surfaces of the heating element and electrically connected to the upper and lower surfaces of the heating element. A flat metal terminal is provided, and a fixing hole that penetrates from the upper metal terminal to the lower metal terminal through the heating element is formed, so that the entire metal terminal is covered except for the power supply part. Since the electrically insulating film is formed, the heater can be screwed to the object to be heated by inserting the screw into the fixing hole. As a result, the upper surface (or lower surface) of the heater can be brought into close contact with the object to be heated, so that the heat generated by the heating element can be efficiently transferred to the object to be heated.

Moreover, since the flat metal terminal is used, the contact surface area between the heater and the object to be heated can be increased. This further improves the heat transfer efficiency.

Further, since the heater is coated with the electrically insulating film, the heating element can be electrically insulated from the object to be heated. Thereby, there is an effect that heating can be performed efficiently regardless of the electrical conductivity of the object to be heated.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a schematic configuration of a heater of the present invention.

FIG. 2 is a perspective view of the heater of FIG.

FIG. 3 is an explanatory view showing a manufacturing method of the heater of FIG.

[Explanation of symbols]

 1 PTC heating element (positive temperature characteristic thermistor) 2 Electrode 3 Metal terminal 3a Power supply section 4 Electrical insulating film

Claims (1)

[Scope of utility model registration request] 1. A flat-plate heating element made of a positive temperature coefficient thermistor, electrodes provided on the upper and lower surfaces of the heating element, and a pair of flat-plate metal terminals electrically connected to the upper and lower electrodes, respectively. A heater having a fixing hole penetrating from an upper metal terminal to a lower metal terminal through a heating element, and an electric insulating film covering the whole of the metal terminal except a power feeding portion.