Title of Invention

AUTOMOTIVE BLOWER MOTOR RESISTOR

Abstract A resistor for blower motor comprising a resistor circuit board (1), a first insulator (20) placed on one side of the circuit board (10), a second insulator (20") placed on the other side of the circuit board (10), a heat-sink frame (30) for housing the said circuit board (10) and the said insulators (20, 20"), a cover (40) covering the first insulator (20) and connected to the heat sink frame (30), a main terminal junction (50) connected to the lower platform of the circuit board (10), a temperature fuse (11) connected between the divided ends in the upper platform of the circuit board (10), a base plate (6) for holding the main terminal junction (50) and supporting the connection between the heat sink frame (30) and the cover (40), wherein the said heat sink frame (30) has an opening (32) in its upper end and the cover (40) has a bent portion (41) so that the temperature fuse (11) is exposed to exterior.
Full Text A BLOWER MOTOR RESISTOR
The present invention relates to a resistor for blower motor. Particularly, the present invention relates to resistor with high efficient heat radiation for blower motor used in automotive air conditioning and heating system.
The conventional blower motor resistor is shown in figure 1. The conventional resistor comprises a resistor circuit board (1) which is placed in between two insulators (2,2'). A main terminal junction (5) in point welded to the circuit board (1). A temperature fuse (6) is installed between the circuit board (1) and epicycle terminal junction (7). The circuit board covered with insulators is located in the heat sink (3) and the whole arrangement is covered by a cover (4).
The temperature fuse of the conventional resistor is not exposed to exterior which increases the susceptibility of temperature fuse to short circuit caused by heat radiation from the internal heat and heat-sink. In the conventional blower motor resistor arrangement, the temperature fuse is located in an enclosed space and the heat from the heat-sink is not dissipated which causes over-current and affects the product reliability due to short-circuit even during normal operation.
Further, the cover of the conventional resistor is made of low thermal conductive material such as stainless steel or electric plated steel and covers the insulator thickness around the heat-sink where the heat produced by resistor circuit board is usually released. This results in reduction of heat radiation efficiency. Therefore frequency of short circuit caused by over heating of temperature fuse is increased. Especially if the temperature fuse is defective and does not short circuit during over-current mode, there is a potential risk for fire to develop due to resistor's low efficiency of heat radiation.

As the main terminal junction of the conventional blower motor resistor is point welded to the front surface of resistor circuit board, there is a possibility of reducing welding efficiency as well.
The object of the present invention is to provide a resistor for blower motor which could overcome the abovementioned drawbacks.
Another object of the present invention is to provide a blower motor resistor with modified heat sink and cover so that the temperature fuse is exposed to exterior improving the efficiency of the heat radiation.
Yet another object of the present invention is to provide a blower motor resistor in which the thickness of the front and rear insulator which surrounds the resistor circuit board is varied and the cover material is selected in such a way to improve the high efficiency of the heat radiation.
Another object of the present invention is to provide a blower motor resistor with high welding efficiency by applying embossing to main terminal junction platform where resistor circuit board is welded.
Accordingly, the present invention provides a resistor for blower motor comprising a resistor circuit board, a first insulator placed on one side of the circuit board, a second insulator placed on the other side of the circuit board, a heat-sink frame for housing the said circuit board and the said insulators, a cover covering the first insulator and connected to the heat sink frame, a main terminal junction connected to the lower platform of the circuit board, a temperature fuse connected between the divided ends in the upper platform of the circuit board, a base plate for holding the main terminal junction and supporting the connection between the heat sink frame and the cover, wherein the said heat sink frame has an opening in its

upper end and the cover has a bent portion so that the temperature fuse is exposed to exterior.
Brief description of the drawings :
Figure 1 shows an expanded view of the conventional blower motor resistor;
Figure 2 shows an expanded view of the blower motor resistor of the present invention;
Figure 3 shows main parts of the blower motor resistor of the present invention;
Figure 4 shows an outline view of the blower motor resistor of the present invention with temperature fuse in installed condition;
Figure 5 shows a front view of the blower motor resistor of the present invention;
Figure 6 shows a cross sectional view of the blower motor resistor of the present invention;
Detailed description of the accompanying drawings
The blower motor resistor according to the present invention is shown in figures 2 to 6. The resistor comprises a circuit board (10) which is covered on its both sides by first and second insulators (20, 20f). A temperature fuse (11) is connected to upper platform of said circuit board (10) and a main terminal junction (50) is point welded to the lower platform of the circuit board (10). The divided ends in the upper platform of the circuit board (10) is point welded to both leads of the temperature fuse (11). The circuit board (10) and the insulators (20, 20') are placed inside a heat-sink frame (30) and covered with a help of a cover (40).

The resistor comprises a base plate (60) which consists of an upper plate (61) and a lower plate (62) for holding the main terminal junction (50) and supporting the connection between the heat sink frame (30) and the cover (40). A heat-sink (31) with crease curvatures is added to the front side of the heat sink frame (30) to increase efficiency of heat radiation. An opening (32) is provided in the upper part of the heat sink to release the heat generated by the temperature fuse (11).
The cover (40) has a bent portion (41) in its upper portion which when connected to the heat sink frame allows the temperature fuse (11) to be exposed to the exterior. The bent portion (41) of the cover also protects the circuit board (10) from being exposed to the exterior. Similarly, the cover (40) structure has exposed area on the front and back of the temperature fuse (11) to quickly lower the temperature even in overheating conditions.
In addition, besides the crease curvature on the front of heat-sink frame (30) the amount of radiant heat transferred to the temperature fuse (11) can be reduced by the opening (32) provided for heat dissipation . This type of structure for heat-sink (31) and the cover (40) increase the efficiency of heat radiation and prevent overheating short circuits when temperature fuse (11) is operated below established temperature at the normal operation. Only caution is temperature fuse (11) should not be in contact with bent portion (41) of cover (40). Due to cover's metallic material property, there is possibility of short circuit when the cover (40) and temperature fuse (11) are in contact.
In the resistor of the present invention, the main terminal junction (50) platform where it is point welded to lower platform of resistor circuit board (10) is embossed (51). In the existing blower motor resistor main terminal junction and resistor circuit board platform wider contact surface (main terminal junction and resistor circuit board platform surface) must be melted during welding, applying high current to the area causing welding efficiency to decrease. To overcome this problem, the resistor of the present invention increased the welding efficiency by decreasing only the

contact surface (welding area) because just the embossed main terminal junction (50) platform and resistor circuit board (10) platform contact area can be melted for welding.
Referring to figure 6, the first insulator (20) which is between the circuit board (10) and the cover (40) is much thicker than the second insulator (20f) which is between the circuit board (10) and the heat-sink (31). The second insulator (20') is thinner than the first insulator (20) to ease the heat deliverance to heat-sink (31) because most of the heat generated by the resistor circuit board (10) is dissipated through heat-sink (31). Preferably, the first insulator (20) thickness should be about 1.5 to 6 times the thickness of the second insulator (201). Also to ease the heat-sink heat transference, the second insulator (20f) thickness should be about 0.1 to 0.15mm instead of existing insulator thickness which is about 0.3mm.
The heat-sink (31) is made of material such as aluminum which has high thermal conductivity.
Further, heat can be transferred through insulator (20) to the cover (40) when resistor is overheated therefore it would be desirable to use material that has high thermal conductivity for the cover (40). Therefore it is preferable to use aluminum composite material for the cover to increase the efficiency of heat radiation.
As explained above, this blower motor resistor of the present invention has high efficiency heat radiation by modifying the heat-sink and cover design to allow the temperature fuse to be exposed to exterior and thus preventing temperature fuse's short circuit and increasing the product reliability.
In addition, the insulator that covers front and back of resistor circuit board is modified in their thickness and the cover material is changed to increase the efficiency of heat radiation and to reduce the potential fire. Further, welding efficiency is increased by embossing the main terminal junction platform.


WE CLAIM :
1. A resistor for blower motor comprising a resistor circuit board (1), a first insulator (20) placed on one side of the circuit board (10), a second insulator (20') placed on the other side of the circuit board (10), a heat-sink frame (30) for housing the said circuit board (10) and the said insulators (20, 20'), a cover (40) covering the first insulator (20) and connected to the heat sink frame (30), a main terminal junction (50) connected to the lower platform of the circuit board (10), a temperature fuse (11) connected between the divided ends in the upper platform of the circuit board (10), a base plate (6) for holding the main terminal junction (50) and supporting the connection between the heat sink frame (30) and the cover (40), wherein the said heat sink frame (30) has an opening (32) in its upper end and the cover (40) has a bent portion (41) so that the temperature fuse (11) is exposed to exterior.
2. The resistor as claimed in claim 1, wherein the heat sink frame (30) comprises heat sink (31) with crease curvatures to increase efficiency of heat radiation.
3. The resistor as claimed in claim 1, wherein the main terminal junction (5) is connected to the circuit board (10) by point welding.
4. The resistor as claimed in claim 1, wherein the first insulator (20) is thicker than the second insulator (20') to ease the heat deliverance to the heat-sink (31).
5. The resistor as claimed in claim 4, wherein the thickness of the first insulator (20) is 1.5 to 6 times of the thickness of the second insulator (20').
6. The resistor as claimed in claim 1, wherein the second insulator (20?) is of 0.1 to 0.15mm thickness.

7. The resistor as claimed in claim 1, wherein the cover (40) is made of
aluminum composite material.
8. The resistor as claimed in claim 15 wherein the main terminal junction (50)
has embossings (51) which is point welded to the lower platform of the circuit
board (10).
9. The resistor as claimed in claim 1, wherein the base plate (60) comprises an
upper plate (61) and a lower plate (62).


Documents:

1861-CHE-2005 AMANDED CLAIMS 03-02-2010.pdf

1861-CHE-2005 EXAMINATION REPORT REPLY RECIEVED 03-02-2010.pdf

1861-che-2005-abstract.pdf

1861-che-2005-claims.pdf

1861-che-2005-correspondnece-others.pdf

1861-che-2005-description(complete).pdf

1861-che-2005-description(provisional).pdf

1861-che-2005-drawings.pdf

1861-che-2005-form 1.pdf

1861-che-2005-form 26.pdf

1861-che-2005-form 3.pdf

1861-che-2005-form18.pdf


Patent Number 241452
Indian Patent Application Number 1861/CHE/2005
PG Journal Number 28/2010
Publication Date 09-Jul-2010
Grant Date 05-Jul-2010
Date of Filing 20-Dec-2005
Name of Patentee WOORY AUTOMOTIVES INDIA PVT. LTD.
Applicant Address A1B MDA INDUSTRIAL COMPLEX, MARAIMALAI NAGAR 603 209, KANCHEEPURAM DIST., INDIA
Inventors:
# Inventor's Name Inventor's Address
1 M J KIM C/O A1B MDA INDUSTRIAL COMPLEX, MARAIMALAI NAGAR 603 209, KANCHEEPURAM DIST., INDIA
PCT International Classification Number H01C007/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA