JPH11144604A - Resistor for air conditioner in automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resistor for an air conditioner in an automobile with high reliability, whose fuses can surely operate even when they are provided in an automobile where the environmental temperature may rise remarkably. SOLUTION: Between a first substrate 15 and a second substrate 25 which have a notch 16, a solder wick 9 soaked with flux 19 is enclosed from the notch 16 to be exposed. A resistance body 10 is installed on the first substrate 15, and a fuse part 13 is installed on the resistance body 10 to come in contact with the solder wick 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistor for an air conditioner for a vehicle, and more particularly to a resistor for an air conditioner for a vehicle having a fuse for interrupting a circuit when a temperature rises.

[0002]

2. Description of the Related Art Automotive air conditioners (car air conditioners)
Is a device that takes in air, heats and cools the taken-in air, and blows out the air into the cabin to perform air conditioning in the cabin. One of the main setting conditions for air conditioning performed by a car air conditioner is the amount of air blown into a vehicle cabin. The amount of air blown is determined by the rotation speed of a blower (blower fan) built in the car air conditioner, and the rotation speed of the blower fan is controlled by a fan motor control device that controls a fan motor that rotates the blower fan. .

[0003] The fan motor control device includes a resistor formed by connecting a plurality of resistors having a predetermined resistance value in series, and supplies the fan motor by changing the total resistance value of the resistor. The power that is being changed.
Since the number of revolutions of the fan motor changes in accordance with the supplied power, the fan motor control device sets the level of the supplied power in the resistor stepwise, and switches the fan motor to switch the fan motor. Can be switched to, for example, high-speed rotation, medium-speed rotation, and low-speed rotation.

[0004] In a circuit for supplying power to a fan motor of such a resistor, when a current flowing through the circuit exceeds a predetermined value, a thermal fuse (hereinafter, referred to as a fuse) for shutting off the circuit and protecting the fan motor and the circuit. Simply referred to as a fuse). Fuses include spring-type fuses provided for coil resistance and plate resistance, and solder-type fuses provided for flat resistance. Among them, the solder type fuse is advantageous in making the resistor thinner than the spring type fuse.

FIG. 2 is a diagram showing an example of a solder type fuse.

The fuse 3 shown in FIG. 2 is composed of a conduction interrupting portion 7 formed on a part of the resistor pattern 1 forming a part of a circuit.
A conductive wire made of solder is generally used. When an abnormality occurs in the fan motor and the motor is locked, the resistor pattern 1 and the solder generate heat by generating Joule heat. At this time, the solder having a relatively low melting point is first melted, the circuit on the resistor 5 is cut off, the supply of power to the fan motor is forcibly cut off, and the fan motor and the circuit can be protected.

As described above, a solder wire is used in such a fuse 3, and a solder solvent called flux is contained inside the solder wire. The flux is a component that reduces and removes the oxide film to increase the “wetting property” of the solder, and is melted together with the solder at the time of soldering so that the soldering can be performed well.

When the solder wire is used as the fuse 3, the flux is melted together with the fuse 3 to remove an oxide film to be formed on the surface exposed by the melting.

[0009]

The flux contained in the solder wire is originally heated by a soldering iron or the like only at the time of soldering, and exhibits the effect of reducing the oxide film. For this reason, it is not required that the characteristics do not change over a long period of time, especially with respect to heat.

However, the fuse 3 may be repeatedly heated due to a rise in the temperature inside the automobile or generation of Joule heat even before the disconnection. In such a case, the flux in the fuse 3 may be thermally denatured and the function of removing the oxide film may be deteriorated.

It is known that the surface of the fuse 3 reacts with oxygen in the air to form an oxide film. The oxide film formed on the surface of the fuse 3 has a higher melting temperature than that of the solder, and may prevent the melted solder from flowing quickly, thereby making it difficult to disconnect the resistor pattern 1.

The above-mentioned thermal denaturation of the flux and oxidation of the surface of the fuse 3 are all activated by the temperature rise of the fuse 3. Therefore, it is considered that this point should be particularly considered in a resistor for a car air conditioner provided in an automobile in which the environmental temperature can be significantly increased.

The present invention has been made in view of the above points, and has as its object to provide a more reliable resistor for a vehicle air conditioner in which a fuse operates more reliably. I do.

[0014]

According to the present invention, there is provided a first substrate having a notch, a wire mesh member exposed from the notch on the first substrate, and A second substrate for holding a wire mesh member together with the first substrate;
A flux enclosed between the second substrate and the second substrate and immersed in the wire netting member, and a circuit provided on the first substrate;
A fuse portion made of molten metal that is provided on the circuit and cuts off the circuit by melting, the fuse portion is provided directly on the wire mesh member exposed from the cutout portion, and the wire mesh is melted at the time of melting. It is a resistor of an air conditioner for a vehicle that is absorbed by a member.

With the above construction, (1) since the fuse portion provided on the circuit is provided directly on the wire mesh member, when it is melted, it is absorbed by the wire mesh member and quickly removed from the circuit. To shut off the circuit.

(2) Since the wire mesh member is immersed in the flux, the absorbed solder can quickly spread throughout the wire mesh member, and high solder absorption efficiency can be obtained.

(3) Since the flux is not directly contained in the fuse portion but is sealed between the first substrate and the second substrate, the flux is hardly affected by heat and is less deteriorated.

(4) The wire netting member itself is also sandwiched between the first substrate and the second substrate, and since only a part thereof is exposed, the wire netting member itself is not easily oxidized, so that it fits well with the molten solder. Even higher solder absorption efficiency can be obtained.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below.

FIG. 1 is a view for explaining the structure of a resistor 50 for a car air conditioner according to the present embodiment. FIG. 1A is a top view showing a main part of the resistor 50, and FIG. 2) is a sectional view taken along line BB 'in FIG. Note that the resistor 50 of the present embodiment is used for, for example, flat resistance.

The resistor 50 holds the first substrate 15 having the notch 16, the solder wick 9 exposed from the notch 16 on the first substrate 15, and the solder wick 9 together with the first substrate 15. A second substrate 25, a flux 19 for immersing the solder wick 9, a resistor 10 forming a part of a circuit provided on the first substrate 15, and a resistor 10
And a fuse portion 13 made of molten metal which is provided on the upper side and interrupts the circuit 10 by melting.

The first substrate 15 is caulked to a second substrate 25 as shown in the figure, and is integrated. The solder wick 9 between the integrated first substrate 15 and second substrate 25 is exposed only to the outside from the notch 16 and is largely sealed between the substrates.

The solder wick 9 is a wire mesh knitted with a metal wire, for example, a copper wire is used as the metal. The cross-sectional diameter of the copper wire is suitably in the range of about 0.01 mm to 1 mm. Further, the solder wick 9 is immersed in a flux 19, and the flux 19 is made of, for example, pine or nicotine.

For the fuse portion 13, a solder having a melting point of about 220 ° C. is used. Since the fuse portion 13 is provided directly on the solder wick 9 exposed from the cutout portion 16 by, for example, a spot method, the fuse portion 13 is absorbed by the solder wick 9 at the time of melting. Further, the melted solder mixes with the flux 19 immersed in the solder wick 9, mixes with the solder wick 9, spreads over the entire area of the solder wick 9, and is quickly removed from between the resistors 10.

When the molten solder is removed from between the resistors 10, the circuit including the resistor 10 is disconnected, and the power supply to the fan motor is cut off.

According to the above-described embodiment, since the fuse portion 13 is provided directly on the solder wick 9, the molten solder flows into the solder wick 9, is absorbed and is quickly absorbed between the resistor 10. Removed from

Further, flux 1 was added to solder wick 9.
Since the solder 9 has been immersed, the absorbed solder spreads quickly to the wire mesh member by being compatible with the solder wick 9.

Further, since the flux 19 is not directly contained in the fuse portion 13 but is sealed between the first substrate 15 and the second substrate 25, the flux 19 is hardly affected by heat, and deterioration due to heat is suppressed. Few. Also Solderwick 9
Since itself is sealed between the first substrate 15 and the second substrate 25, it is hardly oxidized even in an automobile where the environmental temperature may become relatively high, and it is well compatible with molten solder. Therefore, higher solder absorption efficiency can be obtained.

Further, the resistor of the car air conditioner according to the present embodiment has a relatively simple structure and is easy to assemble. In addition, since the fuse portion is of a solder type, it is advantageous in making the resistor thinner.

[0030]

According to the resistor of the automotive air conditioner of the present invention, the molten fuse portion can be quickly absorbed by the wire mesh member. Therefore, the fuse operates more reliably,
The reliability of the resistor of the air conditioner for a vehicle can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a main part of a configuration of a resistor of a car air conditioner according to an embodiment of the present invention, wherein (A) is a top view,
(B) is a sectional view along line BB ′ in (A).

FIG. 2 is a diagram illustrating a main part of a resistor of a conventional car air conditioner.

[Explanation of symbols]

 9: solder wick (wire mesh member), 10: resistor (circuit), 13: fuse part, 15: first substrate, 16: notch, 19: flux, 25: second substrate.

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[Procedure amendment]

[Submission date] November 11, 1997

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

Claims (1)

[Claims] A first substrate (1) having a notch (16).
5), a wire mesh member (9) exposed from the notch (16) on the first substrate (15), and a second wire holding the wire mesh member (9) together with the first substrate (15). And a flux (1) sealed between the first substrate (15) and the second substrate (25) and immersed in the wire mesh member (9).
9) and a circuit (10) provided on the first substrate (15)
A fuse portion (13) made of a molten metal provided on the circuit (10) and interrupting the circuit (10) by melting;
The fuse portion (13) is provided directly on the wire mesh member (9) exposed from the notch portion (16), and is absorbed by the wire mesh member (9) during melting. Characteristic resistors for automotive air conditioners.