JPS6220334Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a temperature detection device for detecting the temperature of an evaporator or blown air in an automobile air conditioner.

It is well known to provide an electric thermoswitch in an automobile air conditioner, and a temperature detection device is used in this type of thermoswitch. This temperature detection device connects a heat sensitive element and a voltage dividing resistor in series, and outputs a voltage value at the connection point as an output signal.

However, in conventional temperature detection devices, the partial voltage resistor is incorporated into a control unit located in the interior of the vehicle, such as below the dashboard of the vehicle. Therefore, fluctuations in the temperature inside the vehicle directly result in fluctuations in the ambient temperature of the voltage dividing resistor, and the fluctuation range is large, so the resistance value of the voltage dividing resistor also fluctuates greatly, which has the disadvantage that accurate temperature detection cannot be performed. It was hot.

Therefore, this idea eliminates the conventional drawbacks caused by the large fluctuations in the ambient temperature of the voltage dividing resistor.
The objective is to improve the accuracy of temperature detection, and the gist of this is to improve the accuracy of temperature detection in a temperature detection device for an automobile air conditioner that uses the voltage value at the connection between a sensing element and a voltage dividing resistor as an output signal. A temperature sensor is constructed by integrally providing a heat-sensitive element and a voltage-dividing resistor on a substrate, and this temperature sensor is placed near the evaporator or its air outlet. Therefore, the fluctuation range of the ambient temperature of the voltage dividing resistor is limited to the fluctuation range of the temperature of the evaporator or the blown air, and since the fluctuation range is small, the fluctuation of the resistance value of the voltage dividing resistor is also small, which solves the above problem. can be achieved.

Examples of this invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of a temperature sensor 1 used in the temperature detection device of this invention, and this temperature sensor 1 has a substrate 2 made of a base material such as an aluminum alloy and coated with an insulating material on both sides. On this substrate 2, a heat sensitive element 3 such as a thermistor and a voltage dividing resistor 4 are integrally printed and provided.

Further, on this substrate 2, electrodes 5a to 5c and conductors 6a to 6c are printed in the same manner, and the conductor 6a
One end of the voltage dividing resistor 4 and the electrode 5a are connected to each other through a conductor 6b, one end of the heat sensitive element 3, the other end of the voltage dividing resistor 4, and the electrode 5b are connected to each other through a conductor 6c. The other end and the electrode 5c are respectively connected. Further, the electrodes 5a to 5c have lead wires 7a to 5c.
7c is connected by soldering or the like.

A convex portion 8 is formed by bending the square of the substrate 2, and the temperature sensor 1 configured in this way is inserted between the fins 10, 10 of the evaporator 9, as shown in FIG. The bottom surface of the substrate 2 is attached to one fin 10, and the bottom surface of the substrate 2 is attached to one fin 10.
0, the protrusions 8 of the substrate 2 are attached to each other in contact with each other.

Incidentally, in the above embodiment, the convex portion 8 of the substrate 2 was formed in a square shape on the substrate 2, but as another embodiment, a second convex portion 8 may be formed.
As shown in the figure, the convex portion 8 may be formed by punching out a portion of the substrate 2 using a punch or the like. Furthermore, such a convex portion 8 is not necessarily necessary; for example, as shown in FIG. Alternatively, the temperature of the blown air that has passed through the evaporator 9 may be detected.

Therefore, in FIG. 5, the temperature sensor 1
The lead wire 7a is connected to a power source, the lead wire 7b is connected to a control unit (not shown), the lead wire 7c is grounded, and the voltage at the connection between the sensing element 3 and the voltage dividing resistor 4 is shown. is output to the control unit as an output voltage _V1 . This output voltage V ₁ is determined by the resistance value R ₁ of the heat-sensitive element 3, which changes depending on the ambient temperature of the temperature sensor 1.
Although it is preferable that the resistance value R ₂ of the voltage dividing resistor 4 is determined only by the general formula R ₂ =R ₀ (1+αΔt), it varies. However, R ₀ is the low resistance value of the voltage dividing resistor 4 at a predetermined temperature, α is the temperature coefficient of the voltage dividing resistor 4, and Δt is the deviation from the predetermined temperature.

However, as mentioned above, since the partial voltage resistor 4 and the heat-sensitive element 3 are arranged near the evaporator or its air outlet, the deviation Δt is limited to the fluctuation range of the evaporator or outlet air temperature, and the deviation Δt is limited to the fluctuation range of the evaporator or outlet air temperature. Δt in the above equation can be almost ignored, and the output voltage V ₁ is accurate.

As described above, according to this invention, since the partial voltage resistor is placed together with the heat-sensitive element near the evaporator or its outlet, fluctuations in the partial voltage resistor due to temperature are reduced, and temperature can be detected accurately. can do.

In addition, the temperature resistance characteristics of heat-sensitive elements vary widely from product to product, so if a voltage dividing resistor is placed on the control circuit side as in the past, it is necessary to modify the control circuit according to the variation in characteristics to ensure accurate temperature control. In contrast, with this invention, the standard values can be made to have the same characteristics by simply trimming the voltage dividing resistor, which makes it possible to deal with the above-mentioned variations and makes adjustment extremely easy. be. Furthermore, since the heat-sensitive element and the voltage-dividing resistor are provided on a thin substrate, it is possible to prevent the wind from becoming a hindrance.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing one embodiment of the temperature sensor used in this invention, Fig. 2 is a perspective view showing another embodiment of the same temperature sensor, and Fig. 3 is an example of the mounting state of the temperature sensor. FIG. 4 is a sectional view showing another embodiment of the present invention, and FIG. 5 is a circuit diagram of a temperature sensor. DESCRIPTION OF SYMBOLS 1... Temperature sensor, 2... Substrate, 3... Heat sensitive element, 4... Voltage division resistor, 9... Evaporator.

Claims (1)

[Scope of utility model registration request] In a temperature detection device for an automobile air conditioner in which the output signal is a voltage value at a connection between a heat-sensitive element and a voltage-dividing resistor, the temperature sensor is formed by integrally providing the heat-sensitive element and the voltage-dividing resistor on a thin substrate. 1. A temperature detection device for an automobile air conditioner, characterized in that the temperature sensor is arranged near an evaporator or an air outlet thereof.