Heating and/or air conditioning apparatus for automotive vehicles

Disclosed is a heating and/or air-conditioning installation for automotive vehicles comprising at least one blower and a flap for affecting the flow of air, and an electronic control device for rotational speed control or speed shifting. The control device which comprises one or more electronic components capable of generating significant amounts of heat, is mounted on the flap, in order to cool the electronic components while only minimally interfering with the flow of air in the heating and/or air-conditioning installation.

BACKGROUND OF THE INVENTION 
The present invention relates to a heating and/or air-conditioning 
apparatus for automotive vehicles. 
Heating and air-conditioning installations for automotive vehicles 
comprising a blower, heat exchanger and flaps to influence the flow of 
air, are already known. It is further known from German Patent No. 27 24 
69 to arrange electronic components, which are capable of generating 
considerable amounts of heat, in planar contact with appropriate cooling 
bodies. 
Cooling surfaces or suitable cooling bodies should be positioned to assure 
sufficient heat removal. Thus, for example, it has already been proposed 
in U.S. Pat. No. 2,786,173 to arrange a power resistor which generates 
significant amounts of heat, outside the passenger compartment, on the 
outside of the dashboard. Such a solution is, however, impractical because 
additional electrical conduits and connections are required, and the 
apparatus cannot be mounted as a complete unit but must be subsequently 
assembled in the vehicle. 
It has further been attempted to arrange electronic components generating 
significant amounts of heat in the blower housing, so that a constant flow 
of air would be available to remove the heat from the cooling elements. It 
has been discovered, however, that such a measure results in an 
appreciable interference with the flow of air and the generation of noise. 
SUMMARY OF THE INVENTION 
It is therefore an object of the present invention to provide a heating 
and/or air-conditioning apparatus for automotive vehicles in which 
electronic components which generate substantial amounts of heat are 
sufficiently and reliably cooled. 
Yet another object of the present invention is the provision of a heating 
and/or air-conditioning apparatus having the above characteristics and in 
which repair and replacement of the electronic structural part is as 
simple as possible. 
Another object of the present invention is to provide a heating and/or 
air-conditioning apparatus for automotive vehicles having the above 
characteristics and which impedes the flow of air to the least possible 
extent. 
In accordance with one aspect of the present invention, there has been 
provided a heating and/or air-conditioning installation for automotive 
vehicles, comprising at least one blower, at least one flap which affects 
the air flow through the installation, and an electronic control structure 
which includes at least one heat-generating structural part mounted on 
said flap. 
Further objects, features and advantages of the present invention will 
become apparent from the detailed description of preferred embodiments 
which follows, when considered with the attached figures of drawing.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
The apparatus according to the present invention not only assures 
satisfactory cooling of the electronic components, but does not require 
additional space in the installation of alterations in the configuration 
of the housing. Depending on the type and the embodiment of the 
installation, the electronic components may be located on different flaps, 
for example, the temperature mixing flap or a fresh air-air recirculation 
baffle. 
In an especially advantageous embodiment of the invention, the flap is made 
of a material having good thermal conductivity, in particular a metal, and 
the electronic component part is connected with the flap to form a joint 
having thermal conductivity. In this manner, the existing flap provides a 
body having a large cooling surface. Since at least one side of the flap 
is always exposed to the flow of air, the relatively large thermal 
conducting surface assures adequate cooling. 
To improve the distribution of heat in the flap, the flap can be equipped 
in the area of the electronic components with areas of increased 
thickness. These thicker flap areas can be molded onto the flap in a 
particularly simple manner if the flap is extruded. 
Power transistors, thermistors and power resistances are examples of 
electronic components capable of generating significant amounts of heat. 
These electronic components, which are arranged on the flap, are connected 
by means of a cable with the electrical system of the vehicle or a control 
device. 
The electronic components may be mounted, depending on the type and 
configuration, on a temperature mixing flap downstream of the blower or on 
a fresh air-air recirculation baffle located on the upstream side of the 
blower. To optimize the flow of air and/or to increase the heat transfer 
surface, additional surface-modifying means can be provided on the flap. 
These surface-modifying means include suitably shaped beads formed in the 
material of the flap, ribs molded onto or metal strips attached by welding 
to the flap. 
In a further embodiment of the present invention, a printed circuit is 
attached to the rear side of the flap on which the electronic control 
device is arranged. This arrangement provides for further integration 
whereby the entire electronic unit for the control of the blower can be 
arranged on a printed circuit. In order to provide the necessary 
installation space for the structural elements of the electronic control 
device, not joined in a thermally conducting manner to the flap, an 
orifice can be provided in the flap between the power transistors. The 
orifice is equipped with a hood like cover. In this manner, the structural 
elements of the electric control device may extend into the orifice of the 
flap, thus requiring only a small distance between the printed circuit and 
the flap. In place of the flap orifice with its hood-like cover, a 
vaulting of the flap may be provided to assure the necessary installation 
space for the structural elements of the electronic control device. The 
structural elements of the electronic control device are in part heat 
sensitive in contrast to the power carrying elements. It is therefore 
proposed to embed the electronic control device in a synthetic resin or to 
provide it with an appropriate cover. This measure further prevents air 
turbulance in the structural elements. 
As mentioned above, the heat-generating component can comprise a PTC 
resistance. In this case, it is convenient to position the PTC resistance 
so that it rests on one side against the flap over a large surface area 
and on the other side facing away from the flap against a metal plate, 
with both the flap and the plate serving as electrical connections for the 
PTC resistance. 
If the heat-developing electronic components are power resistors, it is 
possible to mount the resistors on the flap with the insertion of 
insulating pieces. In this case the power resistors are in the air flow 
and are therefore cooled, but the flap is not involved in the transfer of 
heat. It is, however, also possible to divide the flaps into several 
metallic zones, electrically insulated against each other and to use the 
zones as electrical connections for the power resistors. In this manner, 
the power resistors are supported directly by the metallic zones which 
thus act as cooling bodies. 
In order to facilitate the replacement of the electronic components in the 
course of repairs, it is convenient to assemble the flap from a frame and 
a removable plate and to fasten the electronic components to the plate. In 
this manner, it is not necessary to remove the flap itself from its 
pivoting bearing, but merely to take the plate off the frame. 
It is further advantageous to mount a temperature sensor on the flap, 
which, in case of an excessive generation of heat by the electronic 
components, deactivates the control device for the blower, thereby 
preventing damage due to overheating of the electronic parts. 
With reference to the drawings, FIG. 1 schematically illustrates a housing 
1 of a heating installation for automotive vehicles, comprising a helical 
housing 2 of a radial blower 3 and a plurality of air outlet fittings 4, 5 
and 6. Located between the radial blower 3 and the outlet fittings 4, 5 
and 6 are a heating body 7 and a bypass 9 leading around the heating body. 
The proportion of the air flowing through the heater body 7 and the bypass 
9, respectively, are regulated by means of a pivotally mounted temperature 
mixing baffle 8 located on the air inlet side of the heater body 7. The 
temperature mixing baffle comprises a thermally conductive material and is 
equipped on its circumference with a foam rubber strip 10 to provide good 
sealing. 
An electronic control device 11 for the radial blower 3 is arranged on the 
outside of the helical blower housing 2. Two power transistors 12 and 13 
are mounted on the temperature mixing baffle 8 and are connected by means 
of a cable 14 with the control device 11. The power transistors 12 and 13 
are known to involve an appreciable loss of power combined with the 
generation of a corresponding amount of heat. Accordingly, the 
above-described arrangement transfers the heat from the power transistors 
12 and 13 to the entire surface of the temperature mixing baffle 8 and 
continuously removes the heat by the passage of air along the baffle. 
Additionally, a temperature sensor 24 is fastened to the temperature 
mixing baffle 8 to produce a deactivation of the control device 11 and the 
power transistors 12, 13 if a maximum permissible temperature is exceeded. 
FIG. 2 is a sectional view of the air-conditioning installation of the 
present invention, wherein 15 designates the housing and 16 the helical 
housing of a radial blower 17. The radial blower is followed in sequence 
in the housing 15 by an an evaporator 18. In the housing wall 19, an 
orifice 20 is provided for circulation of air, and an orifice 22 is 
provided in the housing wall 21 for fresh air. The housing walls 19 and 21 
are arranged at an angle to one another. The orifices 20 and 22 can be 
selectively closed by a pivotong flap 23 having a rubber strip on its 
sealing surfaces. The flap 23 serves to affect the respective proportions 
of fresh air and circulating air. The flap 23 has a rubber strip on its 
sealing surfaces. As in the case of the temperature mixing flap in FIG. 1, 
two power transistors 12 and 13 are fastened to the flap 23 and connected 
by means of a cable 14 with an electronic control device (not shown). The 
flap 23 comprises a metal plate having good thermal conductivity, to 
remove the heat generated by the power transistors which is a function of 
their power loss. 
FIG. 3a is a top view of a closing flap 25 comprising two journals 26 for 
pivoting support and a sealing strip 27. The flap 25 further comprises a 
plurality of beads 28 to guide the flow of air. Two power transistors 12 
and 13 are fastened to the flap 25 by means of screws 29. In place of 
beads, the guide elements 28 may be in other forms, for example, as metal 
strips welded to the flap. 
FIG. 3b is a cross-sectional view taken along the line III--III of FIG. 3a. 
Shown from this view, the flap 25 comprises two orifices 30, through which 
the connector pins 31 and 32 of the power transistors 12 and 13 pass to 
the reverse side of the flap 25. The individual wires 33 of the connecting 
cable 14 are soldered to the connector pins 31 and 32 of the two power 
transistors 12 and 13. 
FIG. 3c is a sectional view taken along the line II--II of FIG. 3a. As 
shown in this view, the beads 28 which serve to guide the flow of air, are 
pressed from the material of the flap 25. 
FIG. 4a is a top view of a flap 35, upon which not only the power 
transistors 12 and 13, but also the entire electronic control device is 
mounted. An orifice 36 is located in the flap 35 between the two power 
transistors 12 and 13. The flap is closed in an air tight manner by a hood 
like cover 37. Mounted on the reverse side of the flap 35 by means of 
screws 89 is a printed circuit 38 carrying an electronic control device 
43. 
FIG. 4b is a sectional view taken along the line IV-IV of FIG. 4a. 
According to this view, a printed circuit 38 is mounted by means of 
spacers 42 at a predetermined distance from the flap 35. The connector 
pins 31 and 32 of the power transistors 12 and 13 protrude through the 
printed circuit plate and are soldered to appropriate conductor strips on 
the side of the printed circuit 38 facing away from the flap 35. In the 
area of the orifice 36 of the flap 35 on the printed circuit 38, the 
structural elements of the electronic control device 43 are arranged, with 
the elements 40 of the electronic control device 43 extending into the 
cavity formed by the hood-like cover 37. The connections of the elements 
40 are also soldered to conductor strips on the opposite side of the 
printed circuit 38. 
FIG. 4c illustrates a layout similar to that of FIG. 4b. The difference 
between the embodiments is that the flap 35 does not have an orifice 36 or 
cover 37. Instead, the space needed for the structural elements 40 of the 
control device 43 is provided in the form of a vaulting 41 molded from the 
material of the flap 35. 
FIG. 5 is a sectional view taken through a flap 45, equipped with a journal 
46 for pivoting support, and a sealing strip 47. A PTC resistor 48 rests 
in planar contact against the flap 45 comprising a metallic material 
having good electrical and thermal conductivities. The resistor 48 serves 
both to continuously control the power and to limit the current supplied 
to a blower motor, which is a function of temperature. A metal plate 49 is 
located in planar contact with the PTC resistor 48 on the side facing away 
from the flap 45. Because both the flap 45 and the plate 49 are electrical 
conductors, they serve as electrical connections for the PTC resistance 
48. A continuous bore 50 passes through the flap 45, the PTC resistor 48 
and the plate 49. The bore 50 has an insulating sleeve 51 arranged therein 
with a collar 52 resting against the plate 49. A threaded bolt 53 
protrudes through the insulating sleeve 51, the head of which abutts 
against the collar 52. A nut 54 is screwed on the threaded portions of the 
threaded bolt 53, thereby clamping together the unit comprising the flap 
45, the PTC resistor 48 and the plate 49. In place of the bolt 53 and the 
nut 49, rivets or any other appropriate fastening means can be used. 
FIG. 6 is a cross-sectional view through a flap 55 comprising a material 
having good thermal conductivity. Arranged on the flap 55 are two power 
resistors 56 and 57 which, by virtue of their mounting on suitable angular 
brackets 58, are spaced apart from the flap 55. The angular brackets 58 
simultaneously serve as electrical connectors and are attached by means of 
insulating pieces 59 to the flap 55. The wires of a connecting cable 60 
are also attached to the angular brackets 58. 
FIG. 7 illustrates a flap 61 produced in the form of an extrusion 
comprising areas of larger cross-section, referred to hereinafter as 
"thickenings" 63. The power transistors 12, 13 are attached in the area of 
the thickenings 63, with their connector pins 31, 32 passing through the 
orifices 64. A plurality of ribs are molded onto the flap 61 adjacent to 
the thickenings 63. The ribs serve both to increase the heat transfer area 
and to guide the flow of air. 
As seen from the preceding examples, the arrangement of electrical power 
elements capable of generating large amounts of heat on flaps which are 
exposed to the flow of air is advantageous. It is also possible, 
similarly, to apply to the flap an insulating layer which advantageously 
can be provided with suitable tracks which exhibit the appropriate 
resistivity characteristics. The power resistances formed in this manner 
not only eliminate mounting additional structural elements on the plate, 
but do not result in an increase in resistance to the flow of air in 
comparison to conventional flat flaps. 
In a further embodiment, the flap is formed from a frame and a metal plate 
is releasably fastened to the frame. The electronic components, and 
optionally the control device, are supported by the metal plate. In case 
of failure of the electric circuit, the electronic components and the 
control device may be readily replaced merely by removing and replacing 
the completely equipped plate.