JPH06176857A - Car sheet heater - Google Patents

Abstract

PURPOSE:To enhance the instant heating performance and the safety by forming a car seat heater from a heater unit holding PTC heat emitting element and a controller which senses the current flowing in the PTC element at current feeding and conducts the current feed control. CONSTITUTION:A PTC resistor is chiefly composed of conductive particles, which are prepared by subjecting admixture of crystalline polymer and conductive fine powder to a cross-linking process and a crushing process, and a conductive composition which is prepared by mixing dispersedly carbon particles with a crystal line high-polymer composition, and thus the resistor has a positive resistance temperature coefficient. A heater unit 1 is formed from a controller 2 consisting of a circuit to control the current feed to a PTC heat emitting element 9 held with two cloths 8 as prepared by covering electrode wires with a PTC resistor and further thereover with an electric insulative material. The resultant PTC heat emitting element is equipped with a self-temp. controlling property to provide a high instant heating performance, and if the sensed electric current has deviated from the set value, the current feed to the heat emitting element is controlled. This enhances the safety and the instant heating performance of the car seat heater.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a car seat heater for use in a vehicle seat or the like having a support for disposing and holding a heating wire.

[0002]

2. Description of the Related Art In recent years, vehicle seats have been heated by electric heaters.

In conventional heating with an electric heater, a tubing heater 20 as shown in FIG. 7 is used as a heating element. The tubing heater 20 in FIG. 7 is configured as follows. Reference numeral 21 is a flexible core yarn, 22 is an internal electrode, 23 is a separation layer made of an electrically insulating material, 24 is an external electrode, 25 is an inner polymer layer, and 26 is an outer polymer layer.
In this tubing heater 20, a temperature detection line for measuring the temperature was separately required. Even if the tubing heater 20 can detect the temperature, the temperature control method is difficult and the control circuit becomes complicated. Further, since such a tubing heater 20 has a low immediate heating property, a certain period of time has to elapse from the start of energization until the required temperature is reached. Therefore, the self-temperature control heating element (hereinafter referred to as PTC heating element) is composed of a pair of electrodes sandwiching a resistance element (hereinafter abbreviated as PTC resistor) made of a material having a large positive temperature coefficient in the heating element because of its immediate heating property. A heater unit using (abbreviated) has been considered. This is because when a voltage is applied between the pair of electrodes, the PTC resistor instantly tries to maintain a constant balance between heat dissipation and heat generation due to the current flowing between the electrodes due to the resistance temperature characteristic of the PTC resistor. It is heat-resistant and has a uniform temperature throughout.

[0004]

However, if the resistance temperature characteristic of the PTC resistor material changes with time in this PTC heating element for some reason, the amount of heat generated by the current flowing through the PTC resistor is generated. The self-control temperature determined by the balance of the amount of heat radiation will change. This is because the heat generation temperature increases when the resistance-temperature characteristic of the PTC resistor changes in the direction in which the resistance value decreases. On the contrary, if the change in the resistance-temperature characteristic is such that the resistance value increases, the self-control temperature decreases and P
The TC heating element ceases to generate heat. Conventionally, since there is no means for detecting that the resistance temperature characteristic of the PTC heating element has changed, the resistance temperature characteristic of the PTC heating element changes in a direction in which the self-control temperature increases or decreases (stops heat generation). There was a problem that it could not detect what was done.

An object of the present invention is to solve the above-mentioned problems by detecting an abnormality in the resistance-temperature characteristic of a PTC heating element, and controlling the energization of the PTC heating element when an abnormality occurs so that the vehicle can be used safely. To provide a seat heater.

[0006]

In order to solve the above-mentioned problems, the present invention provides a pair of long metal electrode wires arranged in parallel and facing each other at regular intervals, and a crystalline polymer on the electrode wires. Conductive particles obtained by cross-linking and pulverizing a mixture of conductive fine powder, and a positive resistance temperature coefficient mainly composed of a conductive composition formed by mixing and dispersing carbon particles in a crystalline polymer composition. A PTC heating element formed by integrally covering a resistor having the same and covering the resistor with an electric insulator, a heater unit for holding the PTC heating element, and a current flowing through the PTC heating element when energized is detected. It is provided with a configuration called a controller for controlling energization.

[0007]

According to the present invention, with the above-described structure, a heater unit having a high heat-up property can be obtained from the self-temperature controllability of the PTC heating element, and the detected current value can be detected by detecting the magnitude of the current flowing through the PTC heating element. When the current value deviates from the preset current value range, the energization of the PTC heating element is controlled.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing the basic configuration of a car seat heater according to an embodiment of the present invention.

In FIG. 1, a heater unit 1 is provided in each of a seat portion 4 and a backrest portion 5 of a vehicle seat 3. The heater unit 1 is mounted between the seat portion 4, the skin portion 6 of the backrest portion 5, and the main pad portion 7 to heat the seat surface. In the heater unit 1 used for heating the vehicle seat 3 as described above, two cloth bodies 8 are bonded together as shown in FIG. 2, and a PTC heating element 9 is held between them. 10 is a connector for supplying battery power from the automobile. 2 is PTC
This is a controller that incorporates a circuit that controls the energization of the heating element 9. The heater unit has a cross-sectional shape shown in FIG.

FIG. 4 is a sectional structural view showing the PTC heating element 9. In FIG. 4, reference numeral 11 denotes metal electrode wires arranged in parallel at regular intervals, and conductive particles obtained by subjecting the electrode wires 11 to crosslinking and pulverizing a mixture of a crystalline polymer and conductive fine powder. , The carbon particles are mixed and dispersed in the crystalline polymer composition, and the PTC resistor 12 is covered with a resistor 12 having a positive temperature coefficient of resistance, which is mainly composed of a conductive composition, and the PTC resistor 12 is electrically insulated. Covered with PTC
The heating element 9 is used. The metal electrode wire 11 used was made of 16 copper wires having an outer diameter of 0.1 mm. Further, although polyester is used as the electric insulator 13, it may be polyvinyl chloride, polyphenylene sulfide, or the like. The PTC resistor 12 is made of the following composition. Polyethylene was used as the crystalline polymer composition, and 100 parts by weight of a high-density polyethylene kneaded material containing 60% by weight of furnace black as conductive fine powder was mixed with 4.5 parts by weight of dicumyl peroxide as a crosslinking agent. Was heat-treated at 180 ° C. for 1 hour to freeze-pulverize the crosslinked product to prepare conductive particles having an average particle size of about 50 μm. Then, a mixture of the crosslinked crushed conductive particles and carbon having a particle diameter of about 0.1 μm in a ratio of 10: 1 was kneaded in high-density polyethylene so that the total carbon content was 50% by weight, and the PTC resistance was obtained. Used as the body 12. The PTC resistor 12 showed a volume resistivity value of 6 × 10 ² Ω-cm. Although polyethylene was used as the crystalline polymer in the above-mentioned examples, polyamide, polypropylene or the like may be used.

The surface temperature of the heater unit 1 produced as described above was 55 ° C., which is suitable for contact heating, when DC 12 V was applied from the automobile battery.

FIG. 5 shows resistance-temperature characteristics of the PTC heating element 9 produced as described above. Here, the initial characteristic before the PTC heating element is subjected to the thermal history is T ₀ . T ₁ indicates the resistance-temperature characteristic of the PTC heating element 9 when the resistance value changes in the direction of decreasing resistance value at the same temperature due to the thermal history. This is a change over time due to the heat history
The conductive powder such as carbon particles in the TC resistor 12 agglomerates or the resistance value becomes low due to the mixing of metal powder, etc., and the heat generation temperature becomes higher when compared with the initial characteristics before receiving the heat history. This is the case. The current value in this case is significantly larger than the initial value. Further, T ₂ is a resistance temperature characteristic of the PTC heating element 9 when the resistance value changes in the direction of increasing resistance value at the same temperature due to the thermal history. This is because the PTC resistor 16 in the PTC resistor 16 has a high resistance value due to heat deterioration due to the change over time due to the heat history, and the heat generation temperature is low as compared with the initial characteristics before the heat history. In this case, PT
The current value of the C heating element is significantly smaller than that in the initial period.
In general, the long-term change of the resistance-temperature characteristic of the PTC heating element 9 shows the resistance-temperature characteristic of T ₂ from T ₁ to the initial characteristic of T ₀ .

FIG. 6 shows a control circuit of this embodiment. Both ends of the PTC heating element 9 are electrically connected to the vehicle power supply 14 via the power switch SW and the switch element 18a. Further, a current detecting standard resistor 15 is connected to the circuit, and a current detecting circuit 16 is connected to both ends of the standard resistor 15, and the applied voltage of the automobile power supply 14 and the standard resistor 15 to the PTC heating element 9 are connected. It can detect the current flowing through. The current detection circuit 16 is electrically connected to a determination circuit 17 that determines whether the current value detected here is within a preset current value range. The determination circuit 17 is electrically connected to a relay operating circuit 18, and the relay operating circuit 18 includes a relay power source that performs voltage conversion for operating the relay operating circuit 18 from the vehicle power source 14 via the switch SW. The circuit 19 is electrically connected.

The judgment circuit 17 judges whether or not the magnitude of the detected current value is within a preset range, and sends a control signal to the relay operation circuit 18 according to the judgment result. In the determination circuit 17, when the current value flowing in the PTC heating element 9 is larger than the preset current value, conversely, in the determination circuit 17, the current value flowing in the PTC heating element 9 is the preset current value. Less than, P
Considering that the resistance temperature characteristic of the TC resistor 12 has significantly changed due to the heat history due to heat generation by energization, for the sake of safety, the determination circuit 17 causes the relay operation circuit 18 to switch the switch element 18
Then, the power supply from the automobile power source 14 to the PTC heating element 9 is cut off.

When the determination circuit 17 determines that the detected current value is within a certain range, the relay actuation circuit 18 outputs a signal that is turned on and off in a certain time period according to the magnitude of the detected current value. Give to. With the above control, even if the resistance-temperature characteristic of the PTC heating element 9 changes from T ₁ to T ₂ as shown in FIG. 5, the energization time to the PTC heating element 9 is controlled and the heating temperature is kept constant. Unit 1 can maintain a comfortable temperature.

When measuring the value of the current flowing through the PTC heating element 9, since the temperature coefficient of resistance of the PTC resistor 12 is positive and large, when the PTC heating element 9 is at a low temperature, the rush current flowing at the start of energization is Since the current is very large, the current detected by the current detection circuit 16 is determined after the lapse of a certain time after the start of energization.

According to the above-described embodiment of the present invention, if the PTC heating element has an immediate heating property, the comfortable heating temperature of the heater unit is maintained, and the PTC heating element in the heater unit does not generate abnormal heat or does not generate heat. , The power supply to the PTC heating element is automatically stopped.

[0018]

As described above, according to the car seat heater of the present invention, the following effects can be obtained. (1) Since the heater unit uses a heating element having a positive resistance temperature coefficient, the heating property is improved immediately after the start of energization, unlike the heating property of the conventional electric heater. (2) Due to the self-temperature controllability of the heating element, a temperature sensor for measuring the surface temperature and a complicated temperature adjusting device are not required. Moreover, since the surface temperature of the heater unit itself is stable at about 50 to 55 ° C., the resin products and the like around both seats are not damaged by heat. (3) The current value flowing through the heating element having a positive resistance temperature coefficient is measured and the heating element is energized based on the magnitude of the current value, so that it can be used for a long time at a comfortable temperature. When the PTC heating element abnormally heats up or stops generating heat, the power supply to the heating element is stopped, so that the safety is improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a car seat heater showing an embodiment of the present invention.

FIG. 2 is a perspective view of a heater unit showing an embodiment of the present invention.

FIG. 3 is a sectional view of a heater unit showing an embodiment of the present invention.

FIG. 4 is a sectional view of a PTC heating element showing an embodiment of the present invention.

FIG. 5: Resistance-temperature characteristic diagram of PTC heating element

FIG. 6 is a conduction control circuit diagram of a PTC heating element showing an embodiment of the present invention.

FIG. 7 is a front view of a conventional tubing heater for a heater unit.

[Explanation of symbols]

 1 Heater Unit 2 Controller 9 PTC Heating Element 11 Metal Electrode Wire 12 PTC Resistor 13 Electrical Insulator

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H05B 3/56 7913-3K

Claims (2)

[Claims] 1. A pair of long metal electrode wires arranged parallel to each other at regular intervals and a conductive material obtained by subjecting the electrode wires to a crosslinking treatment and a pulverization treatment with a mixture of a crystalline polymer and a conductive fine powder. Conductive particles and carbon particles are mixed and dispersed in a crystalline polymer composition to cover a resistor having a positive resistance temperature coefficient containing a conductive composition as a main component and integrally molded to form a resistor. A PTC heating element obtained by coating the above with an electrical insulator, and a heater unit for holding the PTC heating element,
A car seat heater including a controller that detects a current flowing through the PTC heating element when energized and controls energization. 2. A controller for detecting a current flowing through a PTC heating element and controlling energization includes a circuit for detecting the magnitude of a current flowing through the PTC heating element, and a detection circuit if the detected current value is within a certain range. 2. The car seat heater according to claim 1, further comprising a circuit configuration for controlling the energization of the heating element and stopping the energization when the temperature is out of a certain range.